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Chlorophyll-a degradation during cellular senescence and death
Abstract
The present study consisted of two parts. First, baseline pigment distributions and potential analytical alterations in 29 microalgal species using ion-paired RP-HPLC/PDA methodology were established. The conversion of chlorophyll-a to chlorophyllide-a easily divided the organisms studied into high and low chlorophyllase activity groups. The idea of species specificity, as to chlorophyllase activity, was reinforced as different species in the same genus behaved differently. A novel compound, tentatively identified as 131-oxydeoxo-chlorophyll-a, was isolated from Euglena gracilis, Thalassiosira sp., Gymnodinium sp. and Dictyota dichotoma. The second and major portion of the study consisted of the dark aging of 9 microalgal clones under anoxic or oxic, warm or cold conditions for periods of up to 31 months. Species with very high chlorophyllase activity produced pheophorbide-a and/or pyropheophorbide-a, usually with chlorophyllide-a being observed as an intermediate. Other species produced only the isomers of pheophytin-a. Four organisms (Anabaena flos-aquae, Closterium sp., Vaucheria sessilis and Nitzschia) were found to produce an early (2–4 months) predominance of pheophorbide-a which, as aging lengthened (4, 6 and 10+ months), gave way to pheophytin-a dominance. As pheophorbide-a is obviously not being converted to pheophytin-a, we propose that pheophorbide-a is being destroyed, possibly enzymatically, to leave pheophytin-a as a more stable survivor in these species. Chlorophyll-b degradation tracked the “a-series”. That is, pheophytin-b or pheophorbide-b dominated according to species patterns for chlorophyll-a. In the green alga Closterium sp., having been aged for 7–31 months, a pigment (3–9% of total a-series) which we have tentatively identified as purpurin-18-phytyl ester was produced and was accompanied by relatively large amounts of pheophytin-a-allomer. We suggest that this compound, formed via the oxidative cleavage of the isocyclic ring, serves as a potential precursor to several open-β position geo-etioporphyrins. The overall degradation of chlorophyll-a and the overlap of catabolic biochemistry with true organic diagenesis is discussed.
... There are two reactions for chlorophylls associated with photoinhibition. The first one involves a structural adjustment of the molecule without destroying its macrocyclic conjugation (Louda et al. 1998), taking place in S. stenophyllum with samples at 15 °C at 7 day. The second one includes cleavage of the macrocyclic ring with pigment destruction (Louda et al. 1998), which might have happened in the samples at 35 °C with the lowest values of the photosynthetic pigments after fifth day and thalli deterioration. ...
... The first one involves a structural adjustment of the molecule without destroying its macrocyclic conjugation (Louda et al. 1998), taking place in S. stenophyllum with samples at 15 °C at 7 day. The second one includes cleavage of the macrocyclic ring with pigment destruction (Louda et al. 1998), which might have happened in the samples at 35 °C with the lowest values of the photosynthetic pigments after fifth day and thalli deterioration. This reduction revealed a positive correlation between pigment content and photosynthetic rate (Louda et al. 1998). ...
... The second one includes cleavage of the macrocyclic ring with pigment destruction (Louda et al. 1998), which might have happened in the samples at 35 °C with the lowest values of the photosynthetic pigments after fifth day and thalli deterioration. This reduction revealed a positive correlation between pigment content and photosynthetic rate (Louda et al. 1998). Therefore, as photosynthetic pigments and effective quantum yield of S. stenophyllum showed non-variation or slight fluctuations at 15, 20, 25 and 30 °C, the treatment + 5 °C seems to trigger a generalized dysfunction probably related to photosynthetic light-harvesting complex and cell integrity, since the phylloids showed unhealthy aspect. ...
Sargassum species form extensive benthic beds in tropical and subtropical low intertidal and subtidal zones, acting as important drivers for marine community structure. Temperature, as one of the most important abiotic factor, affects seaweed performance and triggers changes in metabolic responses; therefore, laboratory experiments involving temperature ranges are tools for understanding seaweed engineering. The aim of this study was to assess the physiological vulnerability and sensitivity of Sargassum stenophyllum C. Martius exposed to five different temperatures by analyzing photosynthetic performance and chemical composition related to carbon and nitrogen metabolism. There were no significant differences in energy quenching between treatments, except at 35 °C, which showed decreased photochemical quenching and increased non-regulated non-photochemical quenching. Chlorophyll a and chlorophyll c at 15 °C and 35 °C exhibited lower amounts at the end of experiment. Protein content showed progressive diminution in the treatments. Total soluble carbohydrates content showed higher concentration as temperature increased. After 7 days, total amino acid content showed increase from 15 °C to 30 °C. No generalization between the amino acid patterns, although glutamine and glutamate content at 15 °C and 35 °C were reduced; and the highest values of isoleucine and leucine were detected at 35 °C. We postulated that accumulation of certain chemical compounds in S. stenophyllum results from a reallocation of carbon and nitrogen, osmoregulation responses and protection against oxidative stress. Results suggest this species’ tolerance ranges between 15 °C and 30 °C and sensitivity at 35 °C.
... The purpurin-18 methyl ester (5) was also obtained from the oxidation of methyl pheophorbide a (1) [52,53], which allowed the addition of different aliphatic amines (butylamine, hexylamine, and octylamine) into the anhydride ring, resulting in products 6-8. Compound 5 exhibited a characteristic absorption at 700 nm, which became approximately 660 nm when the anhydride ring was opened by the insertion of the amines (products 6-8) [54][55][56]. ...
... Compound 5 exhibited a characteristic absorption at 700 nm, which became approximately 660 nm when the anhydride ring was opened by the insertion of the amines (products 6-8) [54][55][56]. The purpurin-18 methyl ester (5) was also obtained from the oxidation of methyl pheophorbide a (1) [52,53], which allowed the addition of different aliphatic amines (butylamine, hexylamine, and octylamine) into the anhydride ring, resulting in products 6-8. Compound 5 exhibited a characteristic absorption at 700 nm, which became approximately 660 nm when the anhydride ring was opened by the insertion of the amines (products 6-8) [54][55][56]. ...
In this study, we describe the semisynthesis of cost-effective photosensitizers (PSs) derived from chlorophyll a containing different substituents and using previously described methods from the literature. We compared their structures when used in photodynamic inactivation (PDI) against Staphylococcus aureus, Escherichia coli, and Candida albicans under different conditions. The PSs containing carboxylic acids and butyl groups were highly effective against S. aureus and C. albicans following our PDI protocol. Overall, our results indicate that these nature-inspired PSs are a promising alternative to selectively inactivate microorganisms using PDI.
... The blotted quartered filter was then wrapped in aluminum foil, labelled, and immediately frozen at minus 30 0 C. The samples taken at Eleuthera in the Bahamas were stored frozen until the senior author picked them up every 3 months and transported to the laboratory at Florida Atlantic University (FAU) in Boca Raton, Florida. At FAU, each filter was extracted using methanol; acetone; dimethyl-formamide; water (30:30:30:10, v/v/v/v) and analyzed for epiphyte pigments (chlorophylls and carotenoids) in accord with our standard high performance liquid chromatography (HPLC) procedures [32,47,54,[66][67][68]. The FAU (JWL) laboratory uses two Waters 990 and three Waters 996 photodiode array spectrometers gathering HPLC data using Waters 990 or Empower-2 software with Waters Nova Pak 3.9x300 mm C18 columns and Thermo Separation Products P4000 quaternary HPLC pumps. ...
... Studies of microalgal senescence and death induced alteration of pigments and pigment ratios [54,[66][67][68][81][82][83][84] have shown that various biomarker carotenoids are rapidly altered (e.g., fucoxanthin) or remain unchanged for years (i.e., alloxanthin, lutein, zeaxanthin) during senescence and death. Consideration of the effects of senescence/death [85], sediment resuspension [53] and light levels [47] all enter the proper application of pigmentbased chemotaxonomy [86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105]. ...
This paper presents pigment-based chemotaxonomy as a rapid method for the analysis of seagrass
epiphyte communities and how that data may be applied to the assessment of the full seagrass ecosystem.
Pigments-based chemotaxonomy uses diagnostic pigments to determine the biomass, using chlorophyll-a
as a proxy, of microalgal taxa within phytoplankton or epiphyte communities. Seagrass samples were
taken from Florida Bay, USA and around the southern tip of Eleuthera Island in the Bahamas.
Data is presented which reveals.
A. The need for care during sampling in order to avoid losing epiphytes due to sloughing,
B. Consideration of the exact site of sampling with a given area,
C. Variations in epiphyte production and community makeup with respect to time of year,
D. Epiphyte loading variations along the length of a seagrass blade,
E. Potential effects of light (top-down) and grazing (bottom-up) on epiphyte communities,
F. The importance of diatoms on the seagrasses and macro-algae of Florida Bay,
G. The use of epiphytometers to monitor epiphyte production versus time, and
H. The strong variation in epiphyte communities around the southern tip of Eleuthera Island.
All of these results and discussion are presented in order to reveal the application of pigment-based
chemotaxonomy and epiphytometers (aka fake seagrass) in the assessment of seagrass epiphyte
communities
Keywords: Epiphytometers; Biodiversity; Atmospheric; Seagrass; Epiphyte; Cyanobacteria
... Prior to injection, 0.125 mL of an aqueous ion pairing (aka ion suppression) solution consisting of 15.0 g of tetrabutylammonium acetate (TBAA) and77.0 g ammonium acetate per liter final volume (Louda et al., 1998;Mantoura and Llewellyn, 1983) was added to 1.0 mL of the filtered extract. ...
... High performance liquid chromatography (HPLC) -photodiode array detection (PAD) involved the injection of 100 or 500µL of the prepared injectate onto a 3.9 × 300mm Waters NovaPak C18 column using a ternary gradient (Louda et al., 1998;Louda et al., 2002) provided by Thermo-Separations-Products (TSP) P4000 quaternary pump. Pigments were detected and PDA generated UV-Vis spectra recorded by a Waters 990 or 996 photodiode array detector with Waters software. ...
The Florida red tide dinoflagellate, Karenia brevis, is the major harmful algal bloom dinoflagellate of the Gulf of Mexico and plays a destructive role in the region. Blooms of K. brevis can produce brevetoxins: ladder-shaped polyether (LSP) compounds, which can lead to adverse human health effects, such as reduced respiratory function through inhalation exposure, or neurotoxic shellfish poisoning through consumption of contaminated shellfish. The endogenous role of the brevetoxins remains uncertain. Recent work has shown that some forms of NADPH dependent thioredoxin reductase (NTR) are inhibited by brevetoxin-2 (PbTx-2). The study presented herein reveals that high toxin and low toxin K. brevis, which have a ten-fold difference in toxin content, also show a significant difference in their ability, not only to produce brevetoxin, but also in their cellular redox status and distribution of xanthophyll cycle pigments. These differences are likely due to the inhibition of NTR by brevetoxin. The work could shed light on the physiological role that brevetoxin fills for K. brevis.
... Pigment degradation within the water column is known to be very rapid and extensive, typically resulting in the breakdown of > 95% of all components already before deposition (Leavitt and Hodgson 2002). The degree of this degradation depends on a large number of factors, including chemical and microbially mediated oxidation (Fimmen et al. 2007), grazing by aquatic invertebrates (Cuddington and Leavitt 1999;Descy et al. 1999;Poister et al. 1999), enzymatic breakdown during algal senescence (Louda et al. 1998), bacterial breakdown (Leavitt and Carpenter 1990) and cell lysis (Louda et al. 1998). In addition, several studies identified three major abiotic factors influencing pigment degradation, namely (1) water temperature (with better pigment preservation in cold than in warm water), (2) transparency (less light favoring pigment preservation), and (3) oxygen content (low oxygen concentrations in the lower water column leading to enhanced preservation, with permanently anoxic conditions being optimal) (Leavitt and Hodgson 2002). ...
... Pigment degradation within the water column is known to be very rapid and extensive, typically resulting in the breakdown of > 95% of all components already before deposition (Leavitt and Hodgson 2002). The degree of this degradation depends on a large number of factors, including chemical and microbially mediated oxidation (Fimmen et al. 2007), grazing by aquatic invertebrates (Cuddington and Leavitt 1999;Descy et al. 1999;Poister et al. 1999), enzymatic breakdown during algal senescence (Louda et al. 1998), bacterial breakdown (Leavitt and Carpenter 1990) and cell lysis (Louda et al. 1998). In addition, several studies identified three major abiotic factors influencing pigment degradation, namely (1) water temperature (with better pigment preservation in cold than in warm water), (2) transparency (less light favoring pigment preservation), and (3) oxygen content (low oxygen concentrations in the lower water column leading to enhanced preservation, with permanently anoxic conditions being optimal) (Leavitt and Hodgson 2002). ...
This study presents the merit of visible-spectrum scanning reflectance spectroscopy (VIS-RS) as a rapid technique for determining the concentration of chlorophyll a (Chl a) and its derivatives in lake sediments. In a 25,000-yr sediment record from Lake Challa, in East Africa, we found that VIS-RS values correlate with Chl a concentrations measured by High Performance/Pressure Liquid Chromatography. Observed variation in sedimentary values of RABD660;670 appears linked to proxies of climatic moisture balance as well as to a seismically-derived lake-level reconstruction over this period, indicating that VIS-RS can be used as a proxy for long-term paleo-hydrological change. Changes in the reflectance of Lake Challa sediments are likely related to differences in the preservation/degradation of algal pigments in response to changes in water-column depth and the stability of stratification. The connecting mechanism may be that during lake lowstands, more frequent injection of oxygen to (near-) bottom waters enhance the breakdown of labile organic compounds before permanent burial. We suggest that fast and inexpensive VIS-RS scanning, although less specific than HPLC in quantifying individual pigments, provides accurate data on down-core variations in the concentration of Chl a and its derivatives in lake sediments, hence allows to reconstruct long-term changes in the hydrology of climate-sensitive lakes. The main prerequisite for its successful application is that temporal variation in lake hydrology over the period of interest has not appreciably affected sedimentation dynamics at the core site, since major changes in sediment texture and organic content are likely to create confounding effects in the VIS-RS signature.
... Pigment degrade already in the water column and after deposition in the sediments as a result of senescence, oxidation, herbivore grazing or bacterial degradation (e.g. Bianchi et al., 1988;Louda et al., 1998Louda et al., , 2002Spooner et al., 1994a,b;Szymczak-Żyła et al., 2006;Welschmeyer and Lorenzen, 1985). The influence of particular factors on pigment content may be different at different sites, so it is not an easy task to compare the extent of eutrophication in different areas based on pigment proxies in sediments, or to make judgements about eutrophication trends (Leavitt, 1993;Reuss et al., 2005). ...
... Chlorophyll-a allomers are characteristic of sediments originating from an oxygenated coastal zone. Chlorophyll-a and pheophorbides-a indicate the presence of comparatively fresh material (Louda et al., 1998(Louda et al., , 2002. Pyropheophorbides-a are mainly a marker for grazing by zooplankton and/or zoobenthos (Bianchi et al., 1998(Bianchi et al., , 2002aHead and Harris, 1996;Szymczak-Żyła et al., 2006). ...
Eutrophication in two different coastal areas – the Gulf of Gdańsk (southern Baltic) and the Oslofjord/Drammensfjord (Norway) – both subject to human pressure and with restricted water exchange with adjacent seas, was investigated and compared. Sediment cores (up to 20cm long) were collected at 12 stations using a core sampler, 6 in each of the two areas, and divided into sub-samples. The physicochemical parameters characterizing the adjacent water column and near-bottom water, i.e. salinity, oxygen concentration and temperature, were measured during sample collection. Chlorophylls-a, -b and -c, their derivatives and selected carotenoids were determined for all the samples, as were additional parameters characterizing the sediments, i.e. Corg, Ntot, δ¹³C and δ¹⁵N, grain size. ²¹⁰Pb activity was also determined and on that basis sediment mixing and accumulation rates were estimated. The distribution of pigments in sediments was related to environmental conditions, the sampling site location and sediment characteristics. The results are in agreement with other observations that eutrophication in the Gulf of Gdańsk has increased, especially since the 1970s, whereas in the Oslofjord it decreased during the same period. The pigments are better preserved in inner Oslofjord sediments than in those from the Gulf of Gdańsk. The results demonstrate that the sum of chloropigments-a in sediments calculated per dry weight of sediments is a valuable measure of eutrophication, providing that the monitoring site is selected properly, i.e. sediments are hypoxic/anoxic and non-mixed. Besides, the results confirm previous observations that the percentages of particular chlorophyll-a derivatives in the sum of chloropigments-a are universal markers of environmental conditions in a basin. The ratios of chloropigments-b and chlorophylls-c to the sum of chloropigments-a (ΣChlns-b/ΣChlns-a; Chls-c/ΣChlns-a) may by applied as complementary markers of freshwater and marine organic matter input, respectively.
... In addition, during the senescence and death of the cells, the chl-a synthesized by algae undergoes degradation to a variety of chl-a derivatives, e.g. pheophytin a, and thus the presence of pheophytin a can be used as an indicator of cell senescence and grazing (Louda et al. 1998;Prins et al. 1991;Strom 1993). ...
... Glutaraldehyde and Lugol's solution are known to cause up to 70% shrinkage of ciliates (Choi and Stoecker 1989;Jerome et al. 1993). Consequently, Homalogastra, Balanion and Rimostrombidium species were the clearest candidates for ice algal grazers in the drift ice, although they are >25 m in size (Kahl 1926;Kim et al. 2007;Liu et al. 2012), while the most abundant ciliates in the drift-ice samples were <10 m (Fig. 6a, (Louda et al. 1998). Likewise, the high concentration of pheophytin a at the bottom of the pack ice (2.8 g l −1 ; Fig. 6b (Fig. 5b, see Supplementary File S1 in the online version at DOI: 10.1016/j.ejop.2016.10.005), and a single copepodid stage IV Eurytemora affinis was found in the surface section of the pack ice, implying that this common Baltic Sea copepod was present as living individuals in the pack ice and perhaps responsible for the herbivory in the bottom-ice section of the pack ice. ...
... These compounds are formed within living or senescent cells, in the water column and during sedimentation (e.g. Barwise and Roberts, 1984;Bianchi et al., 1993;Louda et al., 1998Louda et al., , 2011. The underlying processes are autolytic degradation, photochemical, enzymatic and hydrolytic reactions, microbial or viral lysis and grazing (e.g. ...
... The underlying processes are autolytic degradation, photochemical, enzymatic and hydrolytic reactions, microbial or viral lysis and grazing (e.g. Owens and Falkowski, 1982;Gossauer and Engel, 1996;Louda et al., 1998;Chen et al., 2003). ...
We examined the distributions of tetrapyrrole pigments (i.e. intact chlorophylls and bacteriochlorophylls, pheopigments) as well as their compound-specific carbon and nitrogen isotopic compositions in the sediments of three Swiss lakes (Lakes Rotsee, Cadagno and Zurich) and the Black Sea to investigate the biogeochemical cycling of carbon and nitrogen mediated by phototrophic eukaryotes (algae) and bacteria. The factors controlling chlorin isotope variations are discussed and the feasibility to use chlorins as indicators for reconstructions of surface water environments is evaluated. Chlorophyll a and its derivatives including pheophytin a, a pheophytin a epimer, pyropheophytin a, 132,173-cyclopheophorbide-a-enol, chlorophyllone a as well as steryl and carotenol chlorin esters were detected in all sediments. The presence of bacteriochlorophylls e and their derivatives confirmed the presence of brown strains of green phototrophic sulfur bacteria (Chlorobiaceae; GSB) in all three lakes. In the shallower Lakes Rotsee and Cadagno, purple sulfur bacteria (Chromatiaceae; PSB) were also present as confirmed by bacteriochlorophyll a derivatives. Despite the different degrees of water column hypoxia at the studied sites, the chlorins in all sediments were attributed to rapid transformation of intact tetrapyrroles and the formation of related pheopigments. The scatter of compound-specific carbon isotopic compositions of Chl a and its derivatives resulted from different timing of pheopigment formation, likely due to the interaction of blooms of various phytoplankton communities at different times of the year and the variable degrees of carbon limitation and/or different contributions of recycled organic matter (OM). The nitrogen isotopic composition of the chloropigments mainly derived from nitrate assimilation in Lake Zurich and the Black Sea, whereas ammonium and nitrate assimilation were predominant in Lake Rotsee. In the epilimnion of the meromictic Lake Cadagno, dissolved organic nitrogen (DON) supplied to the surface water from ammonium assimilation in the chemocline may be the main nitrogen source. Phototrophic sulfur bacteria in Lakes Rotsee and Cadagno thrived mainly under dissolved organic carbon depleted conditions within the chemocline and in the hypolimnion. GSB may use predominantly ammonium and at least in Lake Cadagno also perform N2 fixation. In contrast, the nitrogen source of PSB could not be reconstructed with δ15N values of bacteriochlorins, because nitrogen isotopic fractionation during BChl a synthesis seems to be almost independent of the assimilated substrate.
... As mentioned earlier, we could not identify the presence of pyropheophorbide a due to lack of standard and LC-MS. However, we presume its presence in these OMZ sediments as it is a degradation product of Chl a and predominantly formed by grazing processes in the water column and sediments (Bianchi et al., 1998;Louda et al., 1998;Szymczak-_ Zyla et al., 2008). The low concentration of total pheophorbide in 800 m and 1100 m sites may be due to chlorophyll destruction occurs at an early stage of feeding without pheophorbide as intermediate (Head and Harris, 1996). ...
... The low concentration of total pheophorbide in 800 m and 1100 m sites may be due to chlorophyll destruction occurs at an early stage of feeding without pheophorbide as intermediate (Head and Harris, 1996). The downcore decrease of pheophorbide may be due to its further destruction through enzymatic activity as proposed by Louda et al. (1998). Earlier studies showed that pheophorbide a is produced primarily by metazoan grazing activities and their high concentration in sediments suggest that diatoms were actively grazed by heterotrophs in the water column (Bianchi and Findlay, 1991;Bianchi et al., 2002). ...
... Significant correlations between Chl-a and lutein (r = 0.77) and zeaxanthin (r = 0.75) suggest the involvement of these groups in algal biomass. The drought that occurred in the reservoir between 1998 and 2003 may have favored the increase in pigments, as they become more stable when water levels decrease (Louda et al. 1998). Drought periods can impact various aspects of ecosystem dynamics, including primary productivity (Mosley 2015;Rocha Junior et al. 2018). ...
The historical impacts of eutrophication processes were investigated in six subtropical reservoirs (São Paulo, Brazil) using a paleolimnological approach. We questioned whether the levels of pigment indicators of algal biomass could provide information about trophic increase and whether carotenoid pigments could offer additional insights. The following proxies were employed: organic matter, total phosphorus, total nitrogen, photosynthetic pigments (by high-performance liquid chromatography), sedimentation rates, and geochronology (by 210 Pb technique). Principal component analysis indicated a gradient of eutrophication. In eutrophic reservoirs (e.g., Rio Grande and Salto Grande), levels of lutein and zeaxanthin increased over time, suggesting growth of Chlorophyta and Cyanobacteria. These pigments were significantly associated with algal biomass, reflecting their participation in phytoplankton composition. In mesotrophic reservoirs, Broa and Itupararanga, increases and significative linear correlations (r > 0.70) between pigments and nutrients are mainly linked to agricultural and urban activities. In the oligotrophic reservoir Igaratá, lower pigment and nutrient levels reflected lesser human impact and good water quality. This study underscores eutrophication's complexity across subtropical reservoirs. Photosynthetic pigments associated with specific algal groups were informative, especially when correlated with nutrient data. The trophic increase, notably in the 1990s, may have been influenced by neoliberal policies. Integrated pigment and geochemical analysis offers a more precise understanding of eutrophication changes and their ties to human factors. Such research can aid environmental monitoring and sustainable policy development.
... The modifications performed for this previous set of experiments was developed based on the previously published methods. Along these assays we tried to replicate a chromatographic method previously described since the authors used the same column and a similar HPLC equipment as ours to evaluate the concentration of, among others, the three target pigments of our interest: fucoxanthin, β-carotene, and chlorophyll-a [304]. However, as proved by the results displayed (M1-M9) such conditions did not provide enough peak separation and resolution, probably because despite using the same experimental conditions, different parameters change the results such as columns with different lifetimes. ...
In recent decades, numerous marine organisms have been shown to be a promising source of compounds of interest to the food industry, such as vitamins, minerals, polyunsaturated fatty acids, peptides, phenolic compounds, pigments, etc. Algae are among these organisms and have been used as food and traditional remedies, initially in Asian countries but are currently used all around the world. In addition to its good nutritional values, the presence of bioactive compounds has drawn the attention of different areas of research and several industries with the aim of promoting its application as a sustainable raw material for the obtention of new ingredients. Taking this into account, the general objective of this doctoral thesis was to explore the potential of macroalgae from the Galician coastline as a source of bioactives, which resulted as a final purpose to define the optimal conditions for different methodologies for the extraction of fucoxanthin from Undaria pinnatifida.
In an initial screening stage, eight species of macroalgae were considered as possible sources of active compounds: Ulva rigida and Codium tomentosum from the Cholophyta group (green algae), Palmaria palmata and Porphyra purpurea from the Rodophyta group (red algae) and Himanthalia elongata, Laminaria ochroleuca, S. latissima and U. pinnatifida from the Ochrophyta group (brown algae), which are widely present on the Galician coastline and are currently used in the food industry. The chemical composition, nutritional analysis and antioxidant and anti-inflammatory properties of these species were analyzed, revealing a great variability between species and groups. However, the four species of brown algae showed a higher extraction yield, which is a fundamental parameter for the design of subsequent industrial processes. Based on this, brown algae were selected as the study group for future analyses.
In a second stage, it was decided to assess the potential of algae group as a source of bioactive compounds. For this a few more species of brown algae were added to the ones previously used, whose use is not currently widespread, in order to increase the range of evaluation. The added species were Ascophyllum nodosum, Bifurcaria bifurcata, Fucus spiralis, Pelvetia canaliculata and Sargassum muticum, which are all species you can also find in the Galician coastline. In this study, the pigment composition and biological properties of these nine species of brown algae was carried out, using different solvents (ethanol, acetone, hexane, chloroform and ethyl acetate), in order to evaluate the suitability of each one and select the most appropriate. The pigment analysis showed the presence of a wide variety of pigments, highlighting fucoxanthin, which was found in large quantities in all studied species but specially in U. pinnatifida. This carotenoid has gained relevance for a few decades, due to its numerous biological properties, corroborated both in vitro and in vivo. In fact, it has been considered as a functional ingredient for the development of various nutraceutical products, so this molecule was selected as the target compound and the algae U. pinnatifida as the principal extraction matrix. Additionally, ethanol and acetone were able to obtain higher yields, and they are both suitable to be used in the food industry, so they were chosen as extraction solvents.
Once the target compound, matrix, and extraction solvents had been selected, the next step was to design a rapid method HPLC-DAD to quantify fucoxanthin from a large number of samples, in a simple way. This method was used for the optimization stage of the fucoxanthin extraction methods. Firstly, two kinetic studies were carried out to compare the efficiency of both solvents in fucoxanthin extraction. Based on the results, the most efficient solvent for its extraction was ethanol, which is considered a green solvent, suitable for the development of respectable industrial processes with the environment.
Next, the extraction of fucoxanthin from U. pinnatifida was also carried out using innovative extraction techniques as MAE and UAE. This, methodology was used to determine on a laboratory scale, the conditions that allowed the best fucoxanthin extraction performance based on the previously selected factors. In the optimization, variables like power, extraction time and solvent concentration were evaluated, using a response surface methodology. This procedure was used with two different technologies: MAE and UAE, to contrast its effectiveness, and they were compared with a conventional method using a standard SAE. The results showed that through UAE technology the obtained yield was much higher than the one obtained with conventional techniques and also the ones reported in literature.
Lastly, once the best conditions for extraction were determined and the kinetic of fucoxanthin’s extraction was known, the results were discussed with an algae factory and a pilot plant was designed, according to their preferences and specifications, to obtain extracts rich in fucoxanthin at a larger scale. In the pilot plant designed, the alga is washed, desiccated and pulverized preparing it to the extraction in an industrial reactor. After the extraction, the content is filtered, obtaining an extract rich in fucoxanthin, which is finally dehydrated and stored. The final extract was later incorporated into a food product with added nutritional value.
... The modifications performed for this previous set of experiments was developed based on the previously published methods. Along these assays we tried to replicate a chromatographic method previously described by ( Louda et al., 1998 ) since the authors used the same column and a similar HPLC equipment as ours to evaluate the concentration of, among others, the three target pigments of our interest: fucoxanthin, -carotene, and chlorophyll-a. However, as proved by the results displayed ( Fig. 1 M1-M9) such conditions did not provide enough peak separation and resolution, probably because despite using the same experimental conditions, different parameters change the results such as columns with different lifetimes. ...
Seaweeds are photosynthetic organisms that have high contents of pigments. The coloration of each alga is defined by the content and combination of pigments synthesized, which varies among species and environmental conditions. The most abundant pigments in algae are chlorophylls and carotenoids, lipophilic molecules that can be used as natural colorants and have high acceptance by consumers. In this work, a simple and short hands-on time HPLC-DAD method for identifying and estimating the pigment content of algae extracts, specifically fucoxanthin, β-carotene and chlorophyll a was carried out. Using this optimized method, a pigment screening was performed on the ethanolic extracts obtained by ultrasound-assisted extraction from nine brown algae from the Atlantic coastline: Ascophyllum nodosum, Bifurcaria bifurcata, Fucus spiralis, Himanthalia elongata, Laminaria saccharina, Laminaria ochroleuca, Pelvetia canaliculata, Sargassum muticum and Undaria pinnatifida. HPLC results permitted to highlight L. saccharina and U. pinnatifida as promising sources of these three target pigments containing a total amount of 10.5 – 11.5 mg per gram of dry weight. Among them, the most abundant one was fucoxanthin, an added-value compound with a high potential to be commercially exploited by different industries, such as the food, cosmetic, and pharmaceutical sectors.
... Pigment degradation in the water column is rapid compared to the sediment (Leavitt and Hodgson 2001, and references therein). In different habitats (i.e., fresh and marine water), pigment degradation mainly depends on the photooxidation, selective grazing, senescence, sinking rate (different species of living and dead cells) and microbial decay, cell lysis, and enzymatic metabolism during senescence (Louda et al. 1998;Reuss and Conley 2005;Fietz et al. 2005 and reference within). Subsequently, phytoplankton chlorophyll (cells and detritus matters) settled on the surface sediment, degrade more rapidly (Bianchi et al. 2000), and less rapidly (Hurley and Armstrong 1990;Yacobi et al. 1991) during oxic and anoxic conditions, respectively depending on the life strategies of phytoplankton, burrowing invertebrates, and the physical condition of water (Leavitt and Carpenter 1989;Yacobi and Ostrovsky 2012). ...
This study addresses the seasonal distribution of phytoplankton marker pigments (PMP) and the ratios (indicating freshness and fate) from water and surface sediments from the coastal port ecosystem (Paradip port, Odisha, east coast of India) and its utility in understanding phytoplankton pelagic-benthic linkages. Chlorophyll and PMP (for different groups and degradation) distribution revealed distinct seasonality, but the seasonal trend was different for water and sediments. High and low values were observed in the water column during inter-monsoons (fall/spring) and monsoons (southwest/northeast), respectively, whereas, in sediments, the reverse was recorded. However, the contribution of group-specific PMP was different: fucoxanthin > chlorophyll b > zeaxanthin > alloxanthin > peridinin dominated in water and chlorophyll b > zeaxanthin > fucoxanthin > alloxanthin > peridinin in sediment. Selective grazing and stability of sedimentary PMP (fucoxanthin, diatoms PMP, is least stable than other groups) could contribute to such differences. Relatively high chlorophyll:pheopigment ratios in the water and low pheophorbide: pheophytin in sediments indicated the dominance of actively growing microalgae and chlorophyll degradation via chlorophyllidae pathway in the water but not in sediments. These findings suggest that (i) much of the phytoplankton (primarily diatoms) is lost due to herbivory before reaching bottom sediments, and (ii) pigment contribution is determined by selective grazing in water and PMP decay constants in sediments. Documenting such information will give new insights into ecosystem assessment and algal bloom research.
... Photosynthetic microorganisms also show signs of conditional senescence. In dinoflagellates and diatoms, there is a loss in chlorophyll during chloroplast degradation, similar to plant senescence (Messer and Ben-Shaul 1972;Louda et al. 1998). During conditional senescence in green microalgae, thylakoid membranes become more compacted and Communicated by Erko Stackebrandt. ...
Chlamydomonas reinhardtii undergoes conditional senescence when grown in batch culture due to nutrient limitation. Here, we explored plastid and photo-physiological adaptations in Chlamydomonas reinhardtii during a long-term ageing experiment by methodically sampling them over 22 weeks. Following exponential growth, Chlamydomonas entered an extended declining growth phase where cells continued to divide, although at a lower rate. Ultimately, this ongoing division was fueled by the recycling of macromolecules that was obvious in the rapidly declining protein and chlorophyll content in the cell during this phase. This process was sufficient to maintain a high level of cell viability as the culture entered stationary phase. Beyond that the cell viability starts to plummet. During the turnover of macromolecules after exponential growth that saw RuBisCO levels drop, the LHCII antenna was relatively stable. This, along with the upregulation of the light stress-related proteins (LHCSR), contributes to an efficient energy dissipation mechanism to protect the ageing cells from photooxidative stress during the senescence process. Ultimately, viability dropped to about 7% at 22 weeks in a batch culture. We anticipate that this research will help further understand the various acclimation strategies carried out by Chlamydomonas to maximize survival under conditional senescence.
... Demetalation of chl-a to produce pheophytin-a occurs readily when chl-a is free from its stable protein complex. While pheophytin can be formed naturally, e.g., during cell senescence or grazing (Louda et al., 1998(Louda et al., , 2002Bale et al., 2011), it is likely that in this study it represents an artifact of sampling and extraction (transformation of chla) as the sample collection and extraction were not optimized for pigment analysis. The presence of pheophytin-a, whether a natural occurring compound or a proxy for chlorophyll is not surprising as the oxic photic zone of the western Black Sea experiences extensive phytoplankton blooms (Moncheva et al., 2001). ...
Lipids, as one of the main building blocks of cells, can provide valuable information on microorganisms in the environment. Traditionally, gas or liquid chromatography coupled to mass spectrometry (MS) has been used to analyze environmental lipids. The resulting spectra were then processed through individual peak identification and comparison with previously published mass spectra. Here, we present an untargeted analysis of MS 1 spectral data generated by ultra-high-pressure liquid chromatography coupled with high-resolution mass spectrometry of environmental microbial communities. Rather than attempting to relate each mass spectrum to a specific compound, we have treated each mass spectrum as a component, which can be clustered together with other components based on similarity in their abundance depth profiles through the water column. We present this untargeted data visualization method on lipids of suspended particles from the water column of the Black Sea, which included >14,000 components. These components form clusters that correspond with distinct microbial communities driven by the highly stratified water column. The clusters include both known and unknown compounds, predominantly lipids, demonstrating the value of this rapid approach to visualize component distributions and identify novel lipid biomarkers.
... Likewise, a maximum emission of 500 nm refers to lignin autofluorescence [51], main component of plant cell wall. Blue emission, 676 nm, may be associated with pigments belonging to the group of porphyrins as intermediate molecules resulting from chlorophyll degradation during curing process [52][53][54], since those are mostly located in the region corresponding to the external mesocarp constituted by parenchymal cells with significant photosynthetic activity or instead, to a possible presence of phenolic-type molecules associated with antioxidant capacity present in vanilla beans wastes or phenyloplasts [55,56], since they are specialized cells for organic compound storage [57]. ...
Vanilla is one flavoring of worldwide importance, its production demands time from sowing and also an economic investment, thus resulting the processed vanilla obtained as extracts with a yield of 3–5% and the remaining is deemed as waste. However, waste may be used to generate added-value products. Objective of this research was to chemically and microstructurally identify and evaluate the main components of vanilla wastes using green technologies. For such purpose, an enzymatic hydrolysis was carried out separating components which may be employed through biotechnological processes. The presence of monosaccharides was identified in hydrolyzed fraction (HF) and non-hydrolyzed fraction (NHF) by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Mass Spectrometry (MS). Microstructural characterization by Scanning Electron Microscopy (SEM) identified that fraction A constituted by pectin and free sugars is mainly located in internal tissues, lignin-rich D fraction was found in external structures. This work led to a chemical and structural analysis of vanilla beans waste as utilization component and to evaluate the use of enzymes. Further demonstrated is the advantage of enzyme use and their components due to their efficacy and selectivity, as well as the use of environmentally friendly reagents generating an alternative for using referred methodologies towards sustainable development. The identified compounds in vanilla waste hydrolyzed fractions, are within the polymers used as wall material for bioactive compound encapsulation in pharmaceutical, food and fragrances industries, as well as in energy sector for biofuel, production and biosorption of toxic metals in water treatment.
Graphic Abstract
... Chlorophyll a is the most abundant pigment in microalgae , corroborating the literature as the major compound in the S. obliquus profiles obtained by both extraction methods. Nevertheless, the chlorophyll a value in PM30E was much higher (78.32%), followed by its epimer, chlorophyll a′, which may be related to degradation reactions, although microalgae are also able to synthesize it (Louda et al. 1998), so it is not possible to determine its origin. The chlorophyll profile of S. obliquus obtained by MM showed lower chlorophyll a values and higher hydroxychlorophyll a values. ...
There are still limitations in the pigment extraction methods used in microalgae biomass, especially for laboratory scale. This work aimed to develop a simple method for simultaneous extraction of chlorophylls and carotenoids from the microalgae Spirulina sp. and Scenedesmus obliquus. The extraction was performed using a methanol/chloroform (2:1 v/v) mixture with different homogenization times (30, 60 and 120 min); after exhaustive extraction with chloroform, acetone, ethyl acetate, and ethanol were tested and compared with the reference maceration method (MM). Satisfactory recovery values, mostly between 101.1 and 124.2%, were obtained with 30 min of homogenization and extraction with ethanol after chloroform (PM30E). In general, the chlorophyll and carotenoid profiles obtained by the PM30E presented fewer isomers and possible degradation compounds. PM30E showed a reduction of about five times the volume of organic solvents and was four times faster than the MM. In addition, this method provided greater analytical frequency and security for the analyst, since PM30E is performed in a closed system of mechanical homogenization.
... The chlorophyll a concentrations reported here (0.011-0.099 µg g −1 dry sediment) are similar to the lower end of concentrations reported for dry soils (Simmons et al., 2009), and are much lower than concentrations reported for surface microbial mats, which can extend up to 50-100 µg g −1 dry sediment (Geyer et al., 2013;Power et al., 2020). The low values that we measured are likely due to the fact that chlorophyll pigments degrade during cellular senescence after POM enters the hyporheic zone (Louda et al., 1998). Contrary to our prediction, biogenic silica did not predict total chlorophyll pigment concentration (chlorophyll a plus the degradation product pheophytin, Table 2). ...
In low‐nutrient streams in cold and arid ecosystems, the spiraling of autochthonous particulate organic matter (POM) may provide important nutrient subsidies downstream. Because of its lability and the spatial heterogeneity of processing in hyporheic sediments, the downstream transport and fate of autochthonous POM can be difficult to trace. In Antarctic McMurdo Dry Valley (MDV) streams, any POM retained in the hyporheic zone is expected to be derived from surface microbial mats that contain diatoms with long‐lasting silica frustules. We tested whether diatom frustules can be used to trace the retention of autochthonous POM in the hyporheic zone and whether certain geomorphic locations promote this process. The accumulation of diatom frustules in hyporheic sediments, measured as biogenic silica, was correlated with loss‐on‐ignition organic matter and sorbed ammonium, suggesting that diatoms can be used to identify locations where POM has been retained and processed over long timescales, regardless of whether the POM remains intact. In addition, by modeling the upstream sources of hyporheic diatom assemblages, we found that POM was predominantly derived from N‐fixing microbial mats of the genus Nostoc. In terms of spatial variability, we conclude that the hyporheic sediments adjacent to the stream channel that are regularly inundated by daily flood pulses are where the most POM has been retained over long timescales. Autochthonous POM is retained in hyporheic zones of low‐nutrient streams beyond the MDVs, and we suggest that biogenic silica and diatom composition can be used to identify locations where this transfer is most prevalent.
... Alou-Font et al. (2013) also observed a significant accumulation of chlide a in ice algae during the bloom and post-bloom periods in Arctic sea ice, coinciding with a large contribution of empty cells. Chlide a has been considered an index of algal cell senescence due to the activity of chlorophyllase (Jeffrey and Hallegraeff 1987;Louda et al. 1998Louda et al. , 2002. The activity of chlorophyllase, however, may be naturally high in diatoms (Barrett and Jeffrey 1971;Owen and Falkowski 1982;Jeffrey and Hallegraeff 1987). ...
Sea ice algae, comprised mainly of diatoms, are the main primary producers in polar ecosystems, and they are generally
distributed with the highest biomass at the bottom of ice. The taxonomy of ice algae has been traditionally investigated using
light microscopy, but molecular techniques, including pigment analysis, have recently provided new insights into the diversity
and physiology of ice algae. However, no comparative taxonomic survey has been conducted for ice algae thus far. Here,
we investigated differences and similarities in (1) the diversity and (2) the photosynthetic strategies of diatom communities
in sea ice and the underlying seawater of Saroma-Ko Lagoon, Hokkaido, Japan, using algal pigment signatures determined
by ultra-high performance liquid chromatography, light and scanning electron microscopy and Ion Torrent next-generation
sequencing techniques targeting the 18S rRNA gene (i.e., DNA barcoding). Ice algae typically possessed greater biomass
(> 20-fold) and chlorophyll (Chl) a breakdown products than under-ice phytoplankton, suggesting that the ice algae formed
blooms, and cell senescence and disruption could be significant mitigating factors. At the genus level, the diversity of diatoms
in sea ice was higher than in under-ice seawater, although the evenness was comparable or lower in ice algae than in
under-ice phytoplankton. Ice algae had a larger xanthophyll pool size and a higher ratio of photoprotective to photosynthetic
pigments (11-fold and 4.5-fold higher, respectively) than under-ice phytoplankton. The results indicated that ice algae were
well adapted to changes in the light regime, which could partly support their survival capability and high taxonomic diversity.
... Nitrogenous compounds are believed to derive from multiple sources, including amino acids and proteins preferentially preserved in highly reducing environments and from tetrapyrrole plant pigments that can become incorporated into macromolecular OM under a range of redox conditions (i.e., Lewan and Maynard, 1982;Louda et al., 1998). Within oils, nitrogenous compounds occur as alkylated heterocycles with neutral and weakly pyrrolic (containing pyrrole, indole, and carbazole) structures predominating over more basic pyridinic (containing pyridine, quinoline, and benzoquinoline) forms (Richter et al., 1952;Simoneit et al., 1971). ...
To date little is known about the functionalized and heteroatomic compounds present in hydrothermal petroleum and how these compounds are affected by high temperature vent fluids. To address this, the maltene fractions of three hydrothermal petroleum samples spanning the shallow depth of a sediment core collected in the Escanaba Trough of the Gorda Ridge in the northeast Pacific were analyzed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in both negative electrospray ionization (ESI) and negative atmospheric pressure photoionization (APPI) ionization modes. These polar compounds were structurally similar to asphaltenes, but did not exceed a nominal mass range of ∼800 Da. They were derived primarily from terrestrially sourced organic matter (OM) with common heteroatom arrangements of CaHbOc, CaHbOcNd, CaHbNd, CaHbOcSe, CaHbOcNdSe, CaHbNdSe, and CaHbSe. The samples included compounds containing up to 19 oxygen heteroatoms and ranged in size from 10 to 53 carbon atoms with double bond equivalent (DBE) values of 1–38. Molecular formulae with N and S heteroatoms were minor. Within this sulfidic environment the formation and preservation of sulfur heterocyclic compounds was very low, which could be due to sulfurization being out-competed by the high concentrations of metals in the vent fluids or as a result of the thermal instability of C–S bonds. The dominance of oxygenated, and not thiolated, compounds was primarily source-dependent with secondary alteration by aromatization in this system proceeding by H abstraction and reduction of sulfate to H2S. We identified differences in the distributions of heteroatomic compounds caused by the expulsion, thermochemical oxidation, and differentiation of petroleum products during the migration of fluids to the sediment–water interface.
... For example, pigment concentrations or density of the symbiotic zooxanthellae in coral polyps may vary with changes in light, temperature, disease, or the genetic diversity of the symbionts themselves (Kinzie et al., 1984;Anderson et al., 2013;Torres-Pérez et al., 2015;Russell et al., 2016). Changes in algal pigments can occur in response to changes in ambient nutrient or light conditions but may also be an indicator of age or senescence processes (Louda et al., 1998;Bell et al., 2018;Bell & Siegel, in review). Variations in pigment concentrations can affect the magnitude of differences between different parts of the reflectance spectrum and thus the spectral slope (Bell et al., 2015). ...
... S-OChl on the other hand shows a much different visible light response, owing to the minute amount of chlorophyll present in fallen leaves, but nevertheless the UV-response of both samples between 200 nm -300 nm were similar. The blue peak of the S-OChl were noted but greatly attenuated, suggesting that the old chlorophyll extract may not be purely chlorophyll, but a mixture of chlorophyll and other components that were broken down during senescence [32]. ...
The use of textile dyes remain relevant in the issue of water pollution. With the potential harm it may possess on the local flora and fauna, various methods of dye removal have been researched and employed, including photocatalytic degradation. TiO 2 , being a suitable semiconductor for this purpose needs to be sensitized prior to use, either by doping or chemical adsorption in order to activate in visible light. In this study, various natural dyes were employed to sensitize TiO 2 . It was found that chlorophyll was superior in dye degradation, with about a 60% reduction in dye concentration over a target 2 h, greater than that of the synthetic sensitizer N-719. This places chlorophyll based photocatalytic reactors as a potential tool for organic pollutant degradation which are also easy to manufacture and abundant in nature.
... from other three groups. The decline in chlorophyll a/b ratio often means the cellular senescence and death caused by environmental stress (Louda et al., 1998), and the notable decline in CMP-group was due to a lack of available phosphorus. Usually, phosphorus-limited cells are chlorotic (hinder the development of chlorophyll a) relative to nutrient-replete algal cells, and the chlorophyll a content would decrease under phosphorus limitation (Geider et al., 1998). ...
To better understand the promotion effect of phytic acid and its uptake mechanism in freshwater microalga Euglena gracilis, cell growth, photosynthetic pigment content and cell morphology of E. gracilis were evaluated under four conditions: phosphorus deficient group (CMP-), single phosphate treatment group (CMP+), single phytic acid treatment group (CMPA-), and phosphate-phytic acid mixed treatment group (CMPA+). The results showed that phytic acid could serve as the sole phosphorus source for the growth of E. gracilis, and phytase which catalyzes the hydrolysis of phytic acid was discovered for the first time in E. gracilis. Fourier transform infrared spectroscopy combined with multivariate analysis showed the good recognition of metabolites from different culture conditions especially focusing on relative carbohydrate or lipid contents. Phytic acid derived from agro-wastes is a cheap growth promoter for E. gracilis, and this E. gracilis with high nutritional value is applicable to animal feed while minimizing environmental impact.
... Filtered samples were stored at − 80°C until ready for analyses. Photosynthetic (chlorophylls) and photoprotective (carotenoids) pigments were extracted following Hagerthey et al. (2006), separated and identified using Reversed Phase High-Performance Liquid Chromatography (RP-HPLC) with a ternary gradient including ion-pairing reagents (Louda et al. 1998), and quantified by the Beer-Lambert Law relationship using the integrated peak areas at appropriate wavelengths in the Environmental Biogeochemistry Lab at Florida Atlantic University (FAU). Taxon-specific algal biomass (chl a) was estimated using chl a/marker pigment ratios determined by multiple regression/ multiple simultaneous equation formulae (Grant and Louda 2010). ...
The short-term (< 6 months) effects of Hurricane Irma on water quality and phytoplankton community structure were assessed in Biscayne Bay and the adjacent coastal canals from September 2017 through January 2018. The bay experienced sharp fluctuations in daily average salinity and salinity gradients during the passage of the hurricane and significant decreases in salinity as a result of increased freshwater inflows that followed the hurricane (148.2% increase in total inflows in the first week after the hurricane compared to a week before). These decreases were most pronounced in southern and south-central parts of the bay, which experienced the largest post-hurricane increases in freshwater inflows (349.4% and 103.1% in southern and south-central parts of the bay, respectively). Storm-induced increases in inorganic nutrient concentrations stimulated phytoplankton growth in northern, north-central, and southern parts of the bay. Opportunistic phytoplankton taxonomic groups such as chlorophytes and cyanobacteria dominated the total algal biomass pool in the canals, and northern and southern parts of the bay in the weeks following the storm, but they were gradually outcompeted by diatoms in the following months. Changes in spatial-temporal phytoplankton community structure in the months following Hurricane Irma reflect recovery and return to usual seasonal patterns. The effect of Hurricane Irma on water quality and phytoplankton communities was short-lived (< 3 months), suggesting that Biscayne Bay is resilient to tropical cyclones.
... The acid hydrolysis of the phytol alcohol in the chlorophyll molecule is accompanied by the loss of Mg and products pheophorbides. The excision of phytol without separation from Mg is a specific reaction catalysed by the endodogenous enzyme chlorophyllase and which results in chlorophyllides [4,5]. In Iran, algological studies are still scarce and limited to phylogenetic of genes encoding proteins Abstract Cyanobacteria (Blue Green Algae) differ from other types of bacteria in that they have chlorophyll a, which other photosynthetic bacteria don't have. ...
Cyanobacteria (Blue Green Algae) differ from other types of
bacteria in that they have chlorophyll a, which other photosynthetic
bacteria don’t have. In this study, liquid chromatography-mass
spectrometer (LC-MS) has been used for identification of the four
different allomers of chlorophyll (Chlorophyll α, HO-chlorophyll α,
HO-lactone-chlorophyll α and MeO-lactone-chlorophyll a) from Nostoc
sp. The differences in mass spectrometric fragmentation of Extracted
ion chromatogram can be used as a diagnostic tool for the assignment
of the configuration of four different chlorophyll allomers. This case is
the first documented of identification of four different chlorophyll a
allomers from Nostoc sp. in Iran.
... Fucoxanthin was monitored at an absorbance of 450 nm. The following mobile phases and gradients were used: Solvent A (0.5 M ammonium acetate in 85:15 v/v methanol: water), Solvent B (90:10, v/v acetonitrile: water) and Solvent C (100% ethyl acetate) and programmed as follows: 0-5 min 60:40 Solvent A:Solvent B isocratic 5-10 min linear gradient to 100 B; 10-20 min linear gradient from 100 B to 23:77 B:C, hold for 1 min, then to 100C over 4 min [34]. Re-equilibration of the HPLC column consisted of running 100 B for 1 min then gradient to 60:40 A: B over 4 min, hold for 5 min. ...
In order to commercially exploit microalgae for the production of fucoxanthin, species must remain productive in the increasingly saline environment typical in outdoor cultivation ponds. To this end, this study investigated the salinity range, growth, fucoxanthin content and productivity of two halotolerant and four marine microalgae under salinity increase condition. The semi-continuous cultivation followed by gradual salinity increase and slow adaptation helped saline microalgae to extend the salinity range up to 55%. Tested species showed about 12% to 90% more fucoxanthin content at their optimal salinity compared to when grown at non-optimal salinities. Fucoxanthin productivity was found directly linked to biomass productivity. Marine microalgae performed best at salinities < 55‰ (ppt, parts per thousand) and halotolerant microalgae was best at salinities > 55‰. Among marine species, the highest fucoxanthin content and productivity was observed in Chaetoceros muelleri which was 2.92 mg g− 1 and 0.072 mg L− 1 d− 1 of ash free dry weight (AFDW), respectively, at 45‰ and fucoxanthin content was relatively consistent over the range of salinity between 35 and 55‰. Between two halotolerants, Amphora sp. showed the highest content and productivity of fucoxanthin which was 1.2 mg g− 1 and 0.053 mg L− 1 d− 1 of AFDW, respectively at 85‰ salinity. The results indicate that it is most likely possible to achieve continuous production of fucoxanthin by cultivating marine and halotolerant species one after another when salinity rises due to evaporation. Details of fucoxanthin content and productivity for Chrysotila carterae, Chaetoceros muelleri, Amphora sp. and Navicula sp. are reported for the first time.
... Fucoxanthin was monitored at an absorbance of 450 nm. The following mobile phases and gradients were used: Solvent A (0.5 M ammonium acetate in 85:15 v/v methanol:water), Solvent B (90:10, v/v acetonitrile:water), and Solvent C (100% ethyl acetate) and programmed as follows: 0-5 min 60:40 Solvent A:Solvent B isocratic 5-10 min linear gradient to 100 B; 10-20 min linear gradient from 100 B to 23:77 B:C, hold for 1 min, then to 100 C over 4 min (Louda et al. 1998). Re-equilibration of the HPLC column consisted of running 100 B for 1 min then gradient to 60:40 A: B over 4 min, hold for 5 min. ...
In a seawater-based open pond microalgae cultivation system salinity will increase gradually over time due to evaporative loss. Continuous salinity increase would lead to non-optimal salinities which negatively affect the biomass and fucoxanthin productivity. To increase and maintain high overall biomass and fucoxanthin productivity, even in the non-optimal salinity zone, two cultivation methods for marine and halotolerant microalgae were carried out, co-cultivation and stepwise cultivation (sequential cultivation). Two fucoxanthin-producing diatoms, Chaetoceros muelleri (marine) and Amphora sp. (halotolerant), were cultivated at non-optimal salinities between 59 and 65‰. Stepwise cultivation showed approximately 63% higher total biomass and 47% higher fucoxanthin productivity than that of co-culture. The ability to reutilize culture media in the stepwise cultivation increases the sustainability of that method. The use of a stepwise culture regime, coupled with a regimen of gradually increasing salinity, provides the possibility of year round fucoxanthin production from microalgae.
... Both B and Fe have previously been reported to increase Microcystis growth (Gerloff, 1968;Srivastava et al., 2016). While NP exhibited the highest Chl-a relative to the control by day 2, by day 4 it appears that NP has accelerated the onset of senescence (a term representing a range of processes, mostly in reference to declining/degrading Chl-a associated with late stationary/lysis phases resulting from environmental stresses such as nutrient limitation Louda et al., 1998). Station 3 had the highest nutrients and initial concentrations of Chl-a, and on an absolute basis there is a trend of Chl-a diminution over 4 days, with an inverse correlation (R 2 ¼ 0.80) between DChl-a 0-2d and DChl-a 2-4d . ...
Eutrophication or excessive nutrient richness is an impairment of many freshwater ecosystems and a prominent cause of harmful algal blooms. It is generally accepted that nitrogen and phosphorus nutrients are the primary causative factor, however, for systems subject to large anthropogenic perturbation, this may no longer be true, and the role of micronutrients is often overlooked. Here we report a study on Lake Tai (Taihu), a large, spatially diverse and hypereutrophic lake in China. We performed small-scale mesocosm nutrient limitation bioassays using boron, iron, cobalt, copper, molybdenum, nitrogen and phosphorus on phytoplankton communities sampled from different locations in Taihu to test the relative effects of micronutrients on in situ algal assemblages. In addition to commonly-used methods of chemical and biological analysis (including algal phytoplankton counting), we used flow cytometry coupled with data-driven analysis to monitor changes to algal assemblages. We found statistically significant effects of limitation or co-limitation for boron, cobalt, copper and iron. For copper at one location chlorophyll-a was over four times higher for amendment with copper, nitrogen and phosphorous than for the latter two alone. Since copper is often proposed as amendment for the environmental management of harmful algal blooms, this result is significant. We have three primary conclusions: first, the strong effects for Cu that we report here are mutually consistent across chlorophyll-a results, count data, and results determined from a data-driven approach to flow cytometry. Given that we cannot rule out a role for a Fe-Cu homeostatic link in causing these effects, future research into MNs and how they interact with N, P, and other MNs should be pursued to explore new interventions for effective management of HABs. Second, in view of the stimulatory effect that Cu exhibited, management of HABs with Cu as an algal biocide may not always be advisable. Third, our approach to flow cytometry offers data confirming our results from chemical and biological analysis, however also holds promise for future development as a high-throughput tool for use in understanding changes in algal assemblages. The results from this study concur with a small and emerging body of literature suggesting that the potential role of micronutrients in eutrophication requires further consideration in environmental management.
... Phytol is the product of side chain ester bond rupture on chlorophyll that can be combined with protein and polypeptide into macromolecular compound (Schoch and Brown, 1987;Ding and Sun, 2005b) in plant or algae cytoplasm. Therefore, the degradation process of this compound was very complicated including many processes and enzymes (Louda et al., 1998). The degradation of chlorophyll constantly produced new phytol as the released phytol degraded, so phytol decomposed slower as a whole. ...
The hypoxic phenomena of seawater have been found in the Changjiang esturay and its adjacent area for several decades. To study organic matter degradation in seasonal hypoxic seawater, series of stimulated incubation experiments with Skeletonema costatum in seawater under different oxygen saturations were conducted. By tracking variations of lipids originated from the alga, time-dependent concentrations of neutral lipids (hexadecanol, otctadecanol, cholesterol, brassicasterol and phytol) and fatty acids (12:0, 14:0, 16:0, 16:1, 18:0, 18:1(9), 20:5 and 22:6) were obtained during three month of incubation. The results indicate that residence time, oxygen saturation, bacterial community and the structure of lipids were key factors controlling preservation and degradation of lipids in seawater. The degradation rate constants calculated from multi-G model showed that under same oxygen saturation, algal fatty acid degraded faster than neutral lipids, and unsaturated fatty acids degraded faster than saturated fatty acids. Our new discovery showed that degradation rate constant had linear positive correlation with oxygen saturation of seawater, indicating the critical role of oxygen on degradation of algal lipids in hypoxic seawater. The results of this study will be helpful to understand organic carbon cycling in seawater and marine environment more deeply. Future field experiments and investigation should be conducted tracking control factors, especially the role of oxygen saturation on organic matter degradation in natural environment.
... The pooled concentrations of pigments included levels of unidentified derivatives and their degradation products estimated on the basis of their similar spectral properties. Their presence in the samples is due mainly to the physiological condition of the phytoplankton, the state of their growth and the degree of development of the plant community, and only minimally to the measurement procedures (Jeffrey, 1997;Louda et al., 1998;Porra et al., 1997;Repeta and Bjørnland, 1997). The highest estimated levels of derivatives and unidentified pigments come from after-bloom periods when the current phytoplankton population consists mainly of ageing and dead cells. ...
Mathematical formulas are given to describe the changes with depth of concentrations of chlorophylls b, c, and photosynthetic and photoprotecting carotenoids in Baltic phytoplankton resulting from the adaptation of algal cells to ambient conditions. They take into account the spectral variability and differences in intensity, characteristic of the Baltic, in the irradiance penetrating the water, and also the spectral similarities among the spectra of different groups of phytoplankton pigments. The formulas were derived and validated on the basis of an extensive set of empirical data acquired from different parts of the Baltic Sea in 1999–2016. The standard error factor x of these formulas ranges from 1.32 to 1.73. These values are lower than those obtained for formulas derived for ocean waters, in which the influence of allogenic constituents on optical properties is negligibly small: 1.44 and 1.52 respectively in the case of chlorophyll c, and 1.32 and 1.47 respectively for photoprotecting carotenoids. With these formulas, overall levels of the main groups of pigments can be calculated from known irradiance conditions and chlorophyll a concentrations at any depth in a layer equal to one and a half thicknesses of the euphotic layer (i.e. to an optical depth of τ = 7) in the Baltic. The accuracy of these approximations is close to that of estimates of other bio-optical characteristics in this sea. This was confirmed by a validation based on an independent dataset (x from 1.27 to 1.84). © 2018 Institute of Oceanology of the Polish Academy of Sciences
... Chlorophyll c 3 was clearly resolved from other chlorophyll c pigments such as chlorophyll c 1 , and c 2. The importance of optimized extraction and automation on the reproducibility and sensitivity of the HPLC method, particularly when less microalgal biomass is present ( Leeuwe et al., 2006). Chlorophyllide a is the result of the loss of the phytol chain and is a common degraded form of chlorophyll a whose occurrence has been associated with cell senescence due to the enzymatic activity of chlorophyllases ( Louda et al., 1998, Louda et al., 2002). The retention time decreased in the following order (Phaeophytin a > Phaeophytin b > chlorophyll b > chlorophyll a > chlorophyllide a) and predominantly was dependent on the polarity of the mobile phase. ...
The pigment content in microalgae is one of the important features of each species. Four green algae such as G11, G12, G13 and G14 were isolated from different freshwater habitat in Madurai. The isolated microalgae G11, G12, G13 and G14 were closely related to Chloromonas pichinchae (G11), Grasiella vacuolata (G12), Watanabea reniformis (G13) and Scenedesmus deserticola (G14). Thin layer chromatography revealed the presence of xanthophylls, chlorophyll and β-carotene in the isolated green algal strains. In this study, using an optimized method of HPLC, trace pigments were also identified. Chlorophyll a, chlorophyll c 2 , chlorophyll c 3 and β-carotene were identified as the major pigments present in all the four green algae. The retention time decreased in the following order (Phaeophytin a > Phaeophytin b > chlorophyll b > chlorophyll a > chlorophyllide a) and predominantly was dependent on the polarity of the mobile phase. Algal products have widening scope for industries in the form of dyes and bio-plastics which can increase profitability and reduce the biomass waste.
... The sum of chloropigments-a, like β-carotene, is an indicator of primary production (Schüller et al. 2013;Szymczak-Żyła et al. 2017), while specific chlorophyll-a derivatives are markers of environmental conditions (Szymczak-Żyła et al. 2011). As pigments may be degraded to their derivatives by both abiotic and biotic factors, i.e. by light, heat, oxygen, herbivore grazing or microorganism activity, these compounds provide information about conditions in the water column and sediments (Welschmeyer and Lorenzen 1985;Bianchi et al. 1988;Louda et al. 1998Louda et al. , 2002Szymczak--Żyła et al. 2006). Carotenoids together with chlorophylls-c and chlorophyll-b are markers of the main phytoplankton groups (Jeffrey and Vesk 1997). ...
Pigments (chloropigments-a and carotenoids) in sediments and macroalgae samples, collected in Hornsund, in July 2015 and July 2016, were analysed (HPLC) in this work. In spite of the aerobic conditions and the periodic intensive solar irradiation in the Arctic environment, neither of which favour pigment preservation in water column and surface sediments, our results indicate that these compounds can provide information about phytoplankton composition, primary production and environmental conditions in this region. The sum of chloropigments-a, a marker of primary production, in the Hornsund sediments varied from 0.40 to 14.97 nmol/g d.w., while the sum of carotenoids ranged from 0.58 to 8.08 nmol/g d.w. Pheophorbides-a and pyropheophorbides-a made up the highest percentage in the sum of chloropigments-a in these sediments, supplying evidence for intensive zooplankton and/or zoobenthos grazing. Among the carotenoids, fucoxanthin and its derivatives (19’-hexanoyloxyfucoxanthin and 19’-hexanoyloxy-4-ketofucoxanthin) contributed the highest percentage, which points to the occurrence mainly of diatoms and/or haptophytes in the water. The pigment markers show that the input of macroalgae to the total biomass could be considerable only in the intertidal zone.
... Curve fitting yielded the linear relationship given by Eq. (6), with a correlation coefficient of 0.95. This confirms that algal removal was caused mainly by cellular death, which is explained by the chlorophyll-a degradation into pheophytin-a, as reported by Louda et al. (1998). Nevertheless, a small portion of the algal cells potentially escaped from the aeration site, as suggested by Toné et al. (2017) ...
This study consisted of two parts. First, pre-aeration tests were conducted to assess the space-time variability of water quality in a shallow lake. Chlorophyll-a concentration and cyanobacteria cell density varied from 40 to 80 μg L-1 and 0.5-2.0×106 cells/mL, respectively. In the second and major part of the study, aeration tests were carried out to investigate the influence of artificial circulation on the flow hydrodynamics and water quality. Comparison of the measurements taken inside and outside the bubble plumes showed that artificial circulation promotes a faster decay of chlorophyll-a concentration over time. First-order kinetics fitted well the time-variation of depth-averaged chlorophyll-a, cyanobacteria, and pheophytin-a. The net reduction rate of chlorophyll-a and cyanobacteria could be described as a function of a dimensionless parameter β that controls bubble plume hydrodynamics or, alternatively, as a function of the rate of dissipation of turbulent kinetic energy ∈. This net reduction rate of chlorophyll-a could also be linearly related to the net growth rate of pheophytin-a. This suggests that algal removal was caused mainly by cellular death. Finally, the relationships obtained in this study were used to predict the impact of artificial circulation on algal removal in water-supply reservoirs.
... Therefore, an obvious expectation from a photosynthetic cell grown on an organic carbon source in complete darkness would be to continue cell division without synthesis of additional photosynthetic pigments, eventually leading to the complete absence of these pigments in subsequent generations. Although the majority of previous studies on algal heterotrophy support this prediction (Siegesmund et al. 1962;Ohad 1975;Abeliovich & Weisman 1978;Louda et al. 1998;Hörtensteiner 1999;Yang et al. 2000;Horie et al. 2009), there are some reports of the retention of chlorophyll in heterotrophically grown algae (Granick 1951;Yentsch & Reichert 1963;Endo et al. 1974;Kulandaivelu & Senger 1976;Murphy & Cowles 1997;Cheirsilp & Torpee 2012;El-Sheekh et al. 2012;Han et al. 2012). Wilken et al. (2014) carried out a detailed study by cultivating Ochromonas danica E.G. Pringsheim growing phagotrophically on Pseudomonas fluorescens Flugge as a complex organic substrate and showed an increase in Photosystem I:Photosystem II (PSI:PSII) ratio and reduced ribulose 1,5-bisphosphate carboxylase/oxygenase content under mixotrophic conditions. ...
Heterotrophically grown cells of a newly isolated strain of Scenedesmus sp. retained their photosynthetic pigment content after prolonged darkness. When these cells had reached an apparent stationary phase and were subsequently exposed to light (mixotrophy), growth rapidly resumed and the biomass increased by 5.5-fold relative to photoautotrophically grown cultures and doubled compared with heterotrophic cultures. Although it is expected, and supported by the majority of reports in the literature, that dark acclimation of algal cultures should lead to eventual loss of photosynthetic pigments, some algae defy these expectations and synthesize and retain their photosynthetic pigments independent of light, despite the high associated maintenance costs. Here we examined the photosynthetic activity of heterotrophically grown cells in an attempt to explain this variance, using Scenedesmus sp. as a model organism. The photosynthetic capacity of heterotrophically grown cells was comparable with that of autotrophically grown cultures, associated with an interesting set of changes to the photosynthetic apparatus that includes lower nonphotochemical quenching, chlorophyll content, absorption cross-sectional area, higher connectivity between reaction centers, higher electron transport flux per reaction center, and probability at t = 0 that a trapped exciton moves an electron into the electron transport chain beyond the primary quinone electron acceptor, and performance index. As a result, when these heterotrophically grown cultures were transferred back to light, they were still able to perform photosynthesis and enhance overall growth, which was otherwise limited in complete darkness.
... Scraped epiphyte material was lyophilized to obtain a dry weight. Epiphyte pigments were extracted using methanol/acetone/ N,N-dimethylformamide/water (Hagerthey et al., 2006) and analyzed using HPLC analysis according to the methods described in Louda et al. (1998). Total epiphyte load was estimated as leaf-specific chlorophyll a (mg Chl a leaf area À1 ). ...
... Keely, 2006;Scheer, 2006). The primary chlorophylls are subject to a large array of structural transformation and decomposition processes in the water column and the underlying sediments (Bianchi et al., 1993;Furlong and Carpenter, 1988;Louda et al., 1998;Louda et al., 2011). However, despite these pre-and post-depositional structural alterations, chlorophylls and their derivatives in the sedimentary record can be used to reconstruct all groups of phototrophic communities in the past water columns (Keely, 2006). ...
To reconstruct the impact of eutrophication on phototrophic communities and the biogeochemical cycling of carbon and nitrogen in the surface water, we investigated the distributions and carbon and nitrogen isotopic compositions (δ¹³C and δ¹⁵N values) of chlorins in the sediments of Lake Zurich. The chlorin distributions were dominated by chlorophyll a (Chl a) and its derivatives, which reflect rapid degradation to the pheopigments in the water column and sediments of the lake. The δ¹³C values of these sedimentary chlorins followed the historical trends of eutrophication and reoligotrophication, except in the surface sediments, which were characterised by higher relative contributions of aged, redeposited organic matter (OM). The δ¹³C values of the sedimentary chlorins together with bulk sediment δ¹³C values and C/N ratios indicate that the phototrophic communities in the lake used a ¹³C-depleted carbon source, which is mainly of aquatic origin. The δ¹⁵N values of chlorins reflect the predominance of nitrate assimilating phototrophs, especially the non-N2-fixing cyanobacterium Planktothrix rubescens prevalent during sediment deposition. Shifts in δ¹⁵N values of Chl a followed mostly the trends in eutrophication and reoligotrophication, but were also affected by community assemblage shifts to diatoms and/or other cyanobacteria at the end of the 19th century and during the eutrophication maximum in the 1970s. The lower δ¹⁵NChl-a values in the surface sediments coincide with increasing nitrogen to phosphorus ratios and reduced water column mixing that characterise the recent reoligotrophication period and may explain the predominance of P. rubescens in Lake Zurich. In contrast, the higher contributions of laterally transported OM explains the large offset of δ¹⁵N values of the pheopigments relative to Chl a, which is supported by the high radiocarbon age of the surface sediments.
... Keely, 2006;Scheer, 2006). The primary chlorophylls are subject to a large array of structural transformation and decomposition processes in the water column and the underlying sediments (Bianchi et al., 1993;Furlong and Carpenter, 1988;Louda et al., 1998;Louda et al., 2011). However, despite these pre-and post-depositional structural alterations, chlorophylls and their derivatives in the sedimentary record can be used to reconstruct all groups of phototrophic communities in the past water columns (Keely, 2006). ...
... High concentrations of degraded Chl-a products, i.e. chlorophyllide-a and pheophorbide-a at high TChl-a stations indicate a declining bloom (Wright et al., 2010). Chlorophyllide-a and pheophorbide-a can be produced from senesced phytoplankton or by mastication during grazing (Louda et al., 1998;Wright et al., 2010). The high contribution of dinoflagellates-2 observed only at high TChl-a stations (Fig. 4A) suggests that grazing activity by heterophic dinoflagellates was taking place at these stations (Fig. 4B). ...
Phytoplankton community structure and their physiological response in the vicinity of the Antarctic Polar Front (APF; 44 °S to 53 °S, centred at 10 °E) were investigated as part of the ANT-XXVIII/3 Eddy-Pump cruise conducted in austral summer 2012. Our results show that under iron-limited conditions, high total chlorophyll-a (TChl-a) concentrations can be observed at stations with deep mixed layer across the APF. In contrast, light was excessive at stations with shallower mixed layer and phytoplankton were producing higher amounts of photoprotective pigments, diadinoxanthin (DD) and diatoxanthin (DT), at the expense of TChl-a, resulting in higher ratios of (DD+DT)/TChl-a. North of the APF, significantly lower silicic acid (Si(OH)4) concentrations lead to the domination of nanophytoplankton consisting mostly of haptophytes, which produced higher ratios of (DD+DT)/TChl-a under relatively low irradiance conditions. The Si(OH)4 replete region south of the APF, on the contrary, was dominated by microphytoplankton (diatoms and dinoflagellates) with lower ratios of (DD+DT)/TChl-a, despite having been exposed to higher levels of irradiance. The significant correlation between nanophytoplankton and (DD+DT)/TChl-a indicates that differences in taxon-specific response to light are also influencing TChl-a concentration in the APF during summer. Our results reveal that provided mixing is deep and Si(OH)4 is replete, TChl-a concentrations higher than are achievable in the iron-limited APF waters during summer.
Red macroalga Pyropia spiralis thrives in the upper intertidal zone and demonstrates remarkable resilience to environmental fluctuations, attributed to protective mechanisms against factors like solar radiation, temperature, and desiccation. The aim of this is study was assess the thermosensitivity and tolerance of P. spiralis, subjecting to five temperatures (15, 20, 25, 30, and 35 °C) evaluating growth rate, photosynthetic performance, and chemical composition. The hypothesis states that higher temperatures will reduce growth and photosynthesis, overstimulate metabolism, degrade pigment composition, and trigger the synthesis of protective metabolites for stabilizing cellular structures under elevated temperature conditions. The study revealed thermotolerance between 15 and 25 °C, characterized by stable energy dissipation and minimal pigment changes. Yet, at 30 and 35 °C, there was significant thermosensitivity, leading to a notable drop in photosynthesis and pigments. Carbon-to-nitrogen (C:N) ratio, notably below 20 (9.58 at 15 °C and 7.86 at 25 °C), indicated a balanced growth characterized by optimal proportions of minerals, carbohydrates, and proteins. P. spiralis ' nutritional traits make it a promising candidate for use in seaweed-based products. Analysis of specific amino acids highlighted an upward trend at 25 °C, while higher temperatures induced a thermal-response profile associated with osmoprotectants, primary stress signals, and glutathione biosynthesis. Additionally, lower temperatures were linked to increased soluble carbohydrates, whereas higher temperatures inversely impacted protein accumulation. It is crucial to note that, being just one variable, the study provides a partial perspective, highlighting the importance of future, multifactorial analyses.
Cyanobacterial blooms are increasing in frequency and intensity globally, impacting lake ecosystem health and posing a risk to human and animal health due to the toxins they can produce. Cyanobacterial pigments preserved in lake sediments provide a useful means of understanding the changes that have led to cyanobacterial blooms in lakes. However, there is some uncertainty as to whether specific carotenoids are unique to certain genera or types of cyanobacteria. To fill this knowledge gap, we analyzed pigments in 34 cyanobacteria cultures and applied the findings to sediments from three New Zealand lakes. The cyanobacterial carotenoids canthaxanthin, echinenone and zeaxanthin were detected in all cultures, whereas myxoxanthophyll was only detected in ten cultures (Microcoleus, Planktothrix and the picocyanobacteria cultures; Synechococcaceae). The sum of the individual carotenoid concentrations provided the strongest relationship with cyanobacterial biomass (R2 = 0.58) and could be used in paleolimnology studies to evaluate general cyanobacterial abundance. Ratios of canthaxanthin, zeaxanthin and myxoxanthophyll relative to echinenone indicated that carotenoid ratios could be used to differentiate picocyanobacteria and bloom-forming cyanobacteria, to some degree. High zeaxanthin/echinenone ratios were measured in picocyanobacteria and low zeaxanthin/echinenone ratios were measured in bloom-forming cyanobacteria. The zeaxanthin/echinenone ratio was applied to sediment core samples where the cyanobacterial community was also evaluated by 16S rRNA gene metabarcoding, with the zeaxanthin/echinenone ratios showing similar patterns to those observed in the cultures. The preliminary assessment described here suggests that zeaxanthin/echinenone ratios could provide a valuable paleoecological proxy for evaluating historical shifts in cyanobacterial communities and warrants further exploration.
Pigments act as tracers to elucidate the fate of phytoplankton in the world's oceans and are often associated with important biogeochemical cycles related to carbon dynamics in the oceans. They are increasingly used in in situ and remote-sensing applications, detecting algal biomass and major taxa through changes in water colour. This book is a follow-up to the 1997 volume Phytoplankton Pigments in Oceanography (UNESCO Press). Since then, there have been many advances concerning phytoplankton pigments. This book includes recent discoveries on several new algal classes particularly for the picoplankton, and on new pigments. It also includes many advances in methodologies, including liquid chromatography-mass spectrometry (LC-MS) and developments and updates on the mathematical methods used to exploit pigment information and extract the composition of phytoplankton communities. The book is invaluable primarily as a reference for students, researchers and professionals in aquatic science, biogeochemistry and remote sensing.
Pigments act as tracers to elucidate the fate of phytoplankton in the world's oceans and are often associated with important biogeochemical cycles related to carbon dynamics in the oceans. They are increasingly used in in situ and remote-sensing applications, detecting algal biomass and major taxa through changes in water colour. This book is a follow-up to the 1997 volume Phytoplankton Pigments in Oceanography (UNESCO Press). Since then, there have been many advances concerning phytoplankton pigments. This book includes recent discoveries on several new algal classes particularly for the picoplankton, and on new pigments. It also includes many advances in methodologies, including liquid chromatography-mass spectrometry (LC-MS) and developments and updates on the mathematical methods used to exploit pigment information and extract the composition of phytoplankton communities. The book is invaluable primarily as a reference for students, researchers and professionals in aquatic science, biogeochemistry and remote sensing.
Pigments act as tracers to elucidate the fate of phytoplankton in the world's oceans and are often associated with important biogeochemical cycles related to carbon dynamics in the oceans. They are increasingly used in in situ and remote-sensing applications, detecting algal biomass and major taxa through changes in water colour. This book is a follow-up to the 1997 volume Phytoplankton Pigments in Oceanography (UNESCO Press). Since then, there have been many advances concerning phytoplankton pigments. This book includes recent discoveries on several new algal classes particularly for the picoplankton, and on new pigments. It also includes many advances in methodologies, including liquid chromatography-mass spectrometry (LC-MS) and developments and updates on the mathematical methods used to exploit pigment information and extract the composition of phytoplankton communities. The book is invaluable primarily as a reference for students, researchers and professionals in aquatic science, biogeochemistry and remote sensing.
Hatchery production of the tropical sea cucumber Holothuria scabra or sandfish has been successfully demonstrated in various countries, especially during the past decade. However, the main bottleneck in up-scaling production of larger sandfish juveniles is in the nursery phase where land-based facilities are limited in the Philippines compared to other countries. This has led to some promising pioneering research in ocean-based sandfish nurseries in the Philippines. However, site-specific and seasonal inconsistencies in production levels were observed. In this study, a comprehensive experiment comparing 17 replicated nursery culture operations of sandfish juveniles using floating hapas, was conducted across four sites with distinct geo-climatic zones in the Philippines and at different months from 2013 to 2016. We evaluated the performance of the ocean-based floating hapa nursery system by determining the effects of periphyton characteristics and broad-scale differences in meteorological variables to growth and survival of juvenile sandfish within different geo-climatic zones. Our data confirmed high spatial (across site) and temporal (among trials within site) variability in sandfish culture performances. Wind stress was the most significant driver of this variation, which negatively influenced growth and survival of juveniles especially during Cycle 1 (first 30 d). Sandfish growth was positively related to Chl-a and mean temperature, but was negatively impacted by Wind stress, Autotropic Index (AI), total rainfall (∑Rain), and sea-surface atmospheric pressure; while survival was positively affected by phaeophytin and Ash-Free Dry Weight (AFDW) content of the hapa biofilm. In Cycle 2 (succeeding 31–60 d), growth and survival was greatly influenced negatively by the re-stocked density (number of individuals surviving from Cycle 1), while survival was further affected negatively by ∑Rain and AFDW. Our results provide significant information on suitable ocean nursery conditions, periphyton/biofilm characteristics, and spatial-temporal considerations for optimizing production of H. scabra juveniles in floating hapas. We also highlight the negative effects of increasing biomass density when on-growing larger juveniles in this system. These insights are valuable in optimizing management and operation of ocean nurseries for sandfish, not only in various potential sites in the Philippines, but also in many developing tropical countries in the Indo-Pacific.
Submergence-induced leaf senescence may alter chlorophyll metabolism. The objective of this study was to characterize chlorophyll biosynthesis and degradation in contrasting perennial ryegrass (Lolium perenne) in response to submergence stress and recovery. The light-green and fast-growing accession PI238938 and the darker-green and slow-growing cultivar BrightStar SLT were exposed to 0, 6 h, 1-, 3-, and 7-d of submergence stress and 1- and 5- d of de-submergence, respectively. Plant growth of PI238938 were more severely inhibited by submergence stress and recovery. Both accessions showed increased leaf malondialdehyde under stress and recovery, but reduced chlorophyll (Chl) concentrations were observed at 3- and 7-d of stress and at recovery. The reduction in Chl was more severe in BrightStar SLT at 7 d of stress. The concentration of 5-aminolevulenic acid was unaffected by stress but increased at 1d of recovery. Activities of 5-aminolevulinic acid dehydratase (ALAD) involved in Chl biosynthesis remained unchanged under stress and recovery, while the activities of Chl degrading enzymes chlorophyllase (CHL) and pheophytinase (PPH) increased at 3 d or 7 d of stress, and returned to the control level after recovery in both accessions. The downregulation of Chl-biosynthetic genes CHLI, POR, and CHLP and the upregulation of Chl-degrading genes CLH, PPH, and SGR were observed in both accessions under most of the stress periods. BrightStar SLT exhibited much lower expressions of the Chl-biosynthetic genes PBGD, CHS, and CHID under stress, while PI238938 had remarkably higher expressions of genes involved in Chl breakdown including CLH, PPH, PAO, RCCR, and SGR, and the expressions of these genes remained at a higher level at 1 d of recovery. The results indicated that submergence-induced leaf senescence and declines in Chl were associated with downregulation of more Chl-biosynthetic genes in slow-growing genotype and upregulation of more Chl-degrading genes in fast-growing genotype of perennial ryegrass.
The main methods of C-O, C-S, C-N, and C-C bond formation at the periphery of the macocrocycle during chemical modification of phytochlorins in the synthesis of biologically active substances and model compounds and in the independent synthesis of natural chlorins are reviewed.
This study consisted of two parts. First, pre-aeration tests were conducted to assess the space-time variability of water quality in a shallow lake. Chlorophyll-a concentration and cyanobacteria cell density varied from 40-80 micro g/L and 0.5-2.0 10^6 cells/mL, respectively. In the second and major part of the study, aeration tests were carried out to investigate the influence of artificial circulation on the flow hydrodynamics and water quality. Comparison of the measurements taken inside and outside the bubble plumes showed that artificial circulation promotes a faster decay of chlorophyll-a concentration over time. First-order kinetics fitted well the time-variation of depth-averaged chlorophyll-a, cyanobacteria, and pheophytin-a. The net reduction rate of chlorophyll-a and cyanobacteria could be described as a function of a dimensionless parameter B that controls bubble plume hydrodynamics, or alternatively, as a function of the rate of dissipation of turbulent kinetic energy E. This net reduction rate of chlorophyll-a could also be linearly related to the net growth rate of pheophytin-a. This suggests that algal removal was caused mainly by cellular death. Finally, the relationships obtained in this study were used to predict the impact of artificial circulation on algal removal in water-supply reservoirs.
The paper presents the results of experiments to determine the influence of selected physico-chemical factors – oxygen, visible light and temperature – on the decomposition of (1) chlorophylls a, b and c, chlorophyll a derivatives and β-carotene in acetone solution, and (2) chlorophyll a and β-carotene in axenic cultures of the blue-green algae Anabaena variabilis. The results indicate that both in acetone extracts and in blue-green algae cultures these pigments were most sensitive to light and oxygen; temperatures of up to 25 • C had no marked influence on these compounds. Under anoxia in acetone solution, the stability towards light decreased in the order chlorophyll a, chlorophyll b, chlorophylls c. Chlorophyll a, moreover, was less stable than its derivatives – phaeophorbides, phaeophytins, pyrophaeophytins and steryl chlorins – but more stable than β-carotene, in the last case also in the blue-green algae cultures. Decomposition of all the pigments proceeded mainly via the breakdown of the porphyrin macrocycle, since the decomposition products were not detected in the VIS range. On the basis of these experiments one can state that while light and oxygen may have a decisive direct influence on the distribution of chlorophylls and β-carotene in sediments, in the natural environment, temperatures of up to 25 • C may have very little immediate effect.
Phytoplankton pigment composition was studied by means of HPLC during an 8 mo period with emphasis on the diatom spring bloom. Twenty-five different pigments were detected and their concentration patterns are shown. The pigment composition revealed that, besides diatoms, nannoplanktonic cryptomonads and green algae play an important role in the phytoplankton commun-ity of the coastal waters of Roscoff. High concentrations of chlorophyll a degradahon products were never observed. Seven different phaeophorbide a-hke, 2 phaeophytin a-like and phaeophytin b were detected. Correspondence analysis of pigment data can be used to show the dynamics of the phyto-plankton community.
Anoxic and oxic degradation pathways of sedimentary chloropigments were examined by spiking marine sediment with ¹⁴ C‐labeled algal cells and purified chloropigments from the diatom Skeletonema costatum. These experiments suggest that Chl a degrades through multiple pathways. Under oxic conditions, most bulk sedimentary Chl a degraded to various colorless compounds and only a minor fraction degraded to pheophytin a ; added ¹⁴ C‐labeled Chl a also degraded quickly, but 30–40% of this Chl a was converted to pheophytin a. Under anoxic conditions, only a small fraction of bulk Chl a degraded, but added ¹⁴ C‐labeled Chl a continuously degraded and ~30–40% of it was converted to pheophytin a. Pheophytin a is relatively stable under anoxic conditions but degrades under oxic conditions, thus it is a potential end product of chloropigment degradation in anoxic environments.
Degradation pathways are likely dependent on the relative proportion of unassociated Chl a to chlorophyll complexes present in the sediment. Only unassociated Chl a appears to be available for anoxic decomposition. Under oxic conditions, some colorless products were further degraded and solubilized; none of the ¹⁴ C label added as purified pigments was lost under anoxic conditions during the 1‐month incubation. About 80% of the acetone‐extractable ¹⁴ C in labeled cells was lost in 1 month from sediments under oxic conditions and ~30% under anoxic conditions.
Chlorophyllase activity, which degrades chlorophyll a to chlorophyhde a, was investigated in 93 species (113 isolates) of unicellular algae from 10 classes. Chlorophyllide a formation was measured by a simple incubation test in 50 % acetone, followed by chromatography and phase separation techniques. High activity of the acetone-activated chlorophyllase was found in one third of the 68 diatom isolates tested. These included the pennate diatoms Asterionella glacialis, Cylindrotheca fusdormis, Delphinejs sp., Grammatophora oceanica, Navicda sp., Nitzschia (2 spp.),Phaeodactylum tncornutum and Thalassionerna nitzschioides, and the important bloom-forming centric d~atoms Chaetoceros (5 spp.), Detonula pumila, Ditylurn bnghtwellii, Eucampia zodiacus, Lithodesmium undulatum, Skeletonema costaturn, Stephanopyxis turris and Streptotheca tamesis. High activity was also found in 2 out of 3 chrysophyte isolates and 2 out of 7 chlorophyte isolates. In contrast, representatives of 7 other classes showed zero or low activ~ty:dinoflagellates (11 isolates), most prymnesiophytes (9 isolates), cryptophytes (5 isolates), prasinophytes (4 isolates), chloromonads (2 isolates), 1 rhodophyte and 2 cyanophytes. Significant strain-specific differences in chlorophyllase activity in 6 out of 13 diatom species, 1 chrysophyte, 1 prymnesiophyte and 1 chlorophyte were also observed. A serious problem for chlorophyll analysis is that chlorophyllase can be activated by harvesting techniques before extraction takes place. Filtration causes the most extensive conversion of chlorophyll a to chlorophyllide a, particularly in old cultures, but harvesting by centrifugation also causes chlorophyhde formation in some species. The effects are more pronounced in diatoms than other algal groups. The further degradabon of chlorophyllide a to pheophorbide a was seldom encountered. Whlle spectrophotometric and fluorimetric methods would not be seriously affected by chlorophyllase activity (provided pheophorbide a is a minor end product), TLC and HPLC techniques for chlorophylls may be rendered invalid due to artefact formation.
Some 100,000,000 tonnes of chlorophyll are degraded each year, much of it rapidly in autumn, an event visible from space. Here on earth, however, the metabolic fate of the chlorophylls remains, embarrassingly, a biochemical mystery. Part of the reason may be due to difficulties inherent in experimenting with tissue which is itself undergoing rapid senescence. An alternative experimental approach is offered which provides answers to the following questions: Are chlorophylls turned over in young and maturing tissue before senescence? If so, how do the rates compare with the known rates of turnover of other plant tetrapyrroles? Are the rates of turnover in young and maturing tissues slow enough to allow more stable non-senesclng material to be used to study the metabolic fate of chlorophyll?
One-third of the earth’s crust is occupied by land, and this supports a terrestrial vegetation receiving the full visible range of the sun’s radiation. The other two-thirds of the earth’s surface is occupied by the world’s oceans, and these heavily filter the incident radiation. Even at a few meters’ depth, the absorbing and scattering properties of water profoundly alter the light spectrum and reduce the intensity compared to that at the sea’s surface. As a consequence, aquatic plants have evolved a variety of lightharvesting pigment systems for trapping those portions of the visible spectrum available. In contrast, only one light-harvesting pigment system has become dominant in terrestrial plants.
The presence of chlorophyll-a and its derivatives in an environmental sample indicates the presence of oxygenic photoautotrophs. The accessory (-b, -c) and alternate (bacteriochlorophylls-a, -b, -c, -d, -e) chlorophylls and the carotenoids provide additional biomarker specificity. That is, the presence of these pigments gives information about taxonomic structure. In the present study we utilized high performance liquid chromatography (HPLC) / photodiode array (PDA) methodology to investigate the photoautotrophic communities in Lake Okeechobee, Florida. Pigment distributions were measured in unispecific cultures and compared to literature reports on natural populations in order to generate equations for the estimation of the relative abundances of photoautotrophic taxa in seston, epiphytes, and benthic samples from 14 locations in the lake. The taxa and their specific biomarkers considered herein include: anoxygenic Eubacteria (purple and green sulfur bacteria: bacteriochlorophylls-a / -c), Cyanobacteria (myxoxanthophyll), Chlorophyta (chlorophyll-b, lutein), Chrysophyta (fucoxanthin), and Pyrrhophyta (peridinin). The estimate of each taxon was based upon the relative abundance of the specific biomarker pigment for that group and its quantitative relationship to chlorophyll-a. As examples of these methods, the technique of pigment-based chemotaxonomy is applied spatially and temporally to the photoautotrophic communities in Lake Okeechobee.
Results and discussion cover pigment analyses of 36 sediment samples recovered by DSDP Leg 64, and six samples from the cruise. Traces of mixed nickel and copper ETIO-porphyrins were ubiquitous in all sediment samples, except for the very surface (i.e., less than 2m sub-bottom), and their presence is taken as an indication of minor influxes of previously oxidized allochthonous (terrestrial) organic matter.-Authors
Porphyrins and their congeners constitute near ubiquitous components of life forms at the cellular level and above. The isolation and identification of DPEP from a variety of petroleums, shales, bitumens and coals afforded the geochemistry innovators their first precursor-product pair. That is, the presence of the isocyclic ring within a porphyrin from geologic materials constituted good evidence for the fossilisation of the chlorophyll nucleus. This chapter reviews work from 1936 and includes information gained from study of long sediment cores obtained from the DSDP and IPOD.-from Authors
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Colour changes from green to red taking place during ripening of Capsicum annuum fruits are due to transition from chloroplast to chromoplast in the exocarp. It was investigated whether the pathway of chlorophyll breakdown in developing chromoplasts comprises the same enzymatic steps as in the chloroplasts of senescent leaves. Chromoplast membranes contained high activities of phaeophorbide a oxygenase, a key enzyme of chlorophyll breakdown, which in senescent leaves has previously been identified to be responsible for the oxygenolytic cleavage of the porphyrin macrocycle. Properties such as specificity for Pheide a as substrate, requirement for reduced ferredoxin as well as lack of activity in the absence of stroma protein were identical to those of the enzyme from senescent leaves. The first identifiable product of Pheide a cleavage, a colourless fluorescent catabolite, was slightly less polar than the corresponding FCC produced by the oxygenase from barley or rape leaves.
In starving, dark-grown cultures of the mutant C-1.1.10.41-8 of Chlorella fusca the degradation of chl a is associated with the appearance of chlde a, phde a, 10-hydroxyphde a, and pyrophde a. Pyrophde a, accumulated in the cells and in the culture medium, appears to represent the end product of chl a breakdown. Kinetic studies in vitro using an optical test revealed the enzymatic formation of pyrophde a from chlde a via phde a. Apparantly other pathways do not occur. The possible significance of 10-hydroxyphde a is discussed. Pyrophde was identified by chromatographic (HPLC and HPTLC) and photometric (IR) comparison of the product with a reference preparation of this pigment. It is concluded that chl a is degraded in the mutant by the following enzymatic reactions:
Chl a ? chide a ? phde a ?pyrophde a.
-Phytol -Mg - COOCH3
Chlorophylls a and b are easily altered chemically when leaves or leaf extracts are exposed to treatments which include heating and the action of organic solvents. Monitoring by thin-layer chromatography assists in the detection of the chlorophyll derivatives. In addition to loss of magnesium, formation of chlorophyllides and the a′ and b′ isomers, and loss of colour, chlorophylls a and b can each be converted into two other derivatives, with absorption spectra almost identical with those of the parent compounds. The conditions of formation, purification and some of the properties of these derivatives are described, and possible structures are discussed.
The enzymatic degradation of chlorophyll a and the formation of chlorophyllide a, phaeophytin a, and phaeophorbide a were detected in vitro in several species of marine phytoplankton. Loss of phytol and Mg2+ were found to be catalysed by chlorophyllase and a magnesium-releasing enzyme, respectively. The activities of the two enzymes could be distinguished from each other by inhibiting with Mg2+ and/or p-chloromercurobenzoate. Both enzymes are activated by cell disintegration. Degradation products were not detected spectrophotometrically in vivo. Additionally, in some species, chlorophyll a was degraded to products which do not absorb visible light.
The separation and purification of the main oxidized derivatives of pheophorbide a and b by reversed-phase TLC afforded their characterization by physical and spectroscopic properties. Their subsequent separation and identification by reversed-phase HPLC was achieved using a system of gradient elution. Under these conditions the separation of rhodin g7, chlorin e6, pheophorbide b, pheophorbide a, purpurin b, pyropheophorbide b, pyropheophorbide a and purpurin a was achieved in 15 min.
Upon examining combinations of environmental conditions most likely to elicit nuisance blooms, commonalities and analog situations become more apparent among coastal marine (dinoflagellate-dominated), estuarine (dinoflagellate- and cyanobacteria-dominated), and freshwater (cyanobacteria-dominated) ecosystems. A combination of the following hydrological, chemical and biotic factors will most likely lead to bloom-sensitive waters: a horizontally distinct water mass; a vertically stratified water column; warm weather conditions, as typified by dry monsoon tropical climates and summer seasons in temperate zones; high incident photosynthetically active radiation (PAR); enhanced allochthonous organic matter loading (both as DOC and POC); enhanced allochthonous inorganic nutrient loading (N and/or P); adequate availability of essential metals, supplied by terrigenous inputs or upwelling; underlying sediments physically and nutritionally suitable as "seed beds' for resting cysts and akinetes; algal-bacterial synergism, which exhibits positive impacts on phycosphere nutrient cycling; algal-micrograzer (protists and rotifers) synergism, which also enhances nutrient cycling without consumption of filamentous and colonial nuisance taxa; and selective (for non-nuisance taxa) activities of macrograzers (crustacean zooplankton, larval fish). Nuisance bloom taxa share numerous additional physiological and ecological characteristics, including limited heterotrophic capabilities, high degrees of motility, and toxicity. -from Authors
Several porphyrin acids [(1)–(6); C30–C33] have been isolated from the Messel oil shale and identified by nuclear Overhauser effect studied and synthesis; they imply the existence of several diagenetic pathways leading from the chlorophylls to the alkylpetroporphyrins.
Pheophytin a and pheophorbide a were measured with reverse-phase, high-performance liquid chromatography (HPLC) in samples from Dabob Bay, a temperate fiord in Puget Sound, Washington. Pheopigment diversity was higher than expected in all samples analyzed (water column, sediment trap material, and fecal pellets of Calanus paczjicus): two major forms of pheophytin a and three major forms of pheophorbide a were separated and quantified. These pigments were labeled by their relative polarity al and a2 in the case of pheophytin and al, a2, and a3 in the case of pheophorbide, with a 1 being the most polar. Pheophytin a 1 and pheophorbide a2 had the same Chromatographic characteristics as the in vitro forms obtained by acidification of Chl a in acetone and chlorophyllide a in methanol. Pheophorbide a 1 was present only in the euphotic zone. Pheophorbide a2 showed a maximum at the depth of the Chl a maximum and was least abundant in sediment traps. Pheophorbide a3 was most abundant below the euphotic zone, in sediment traps, and in C. pacijicus fecal pellets. Pheophytin forms showed no clear pattern, although pheo. phytin a2 was more abundant in laboratory experiments than in field samples. The total mass concentration of pheophorbide forms was four times higher, on average, than that of pheophytin forms (n = 64). Because of their field distributions, the more polar may be the more degraded forms of the chlorophyll molecule.
Chlorophyll production and pigment resuspension were both major sources of water column pigments. Photodegradation rates were rapid and indicated that detritus particles that remained in the epilimnion for periods > 3 days lost nearly all detectable pigments. Therefore, only rapidly sinking detrital particles or those produced in deep layers at low light intensity could make appreciable contributions to sedimentary chlorophyll degradation products. Pheophorbide a, a grazing indicator, was the dominant chlorophyll a degradation product found in sediment traps. Pigment sedimentation increased significantly with mean size of cladocerans and omnivorous copepods. In contrast, sedimentation rates of chlorophyll degradation products did not increase with primary production. In these lakes, deposition of chlorophyll degradation products in sediments depended primarily on size and biomass of grazers. -from Authors
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Chlorophyll destruction by Calanus spp. grazing on phytoplankton (diatoms and Phaeocystis) was assessed at stations in the Labrador Sea and off Labrador and Newfoundland (Canada). Copepods were fed at natural or diluted food concentrations over several (4 to 8) sequential 12 h feeding periods. Initial chlorophyll concentrations were between 0.2 and 19 mu g 1(-1), and degrees of chlorophyll destruction were between 20 and 100%. For replicate incubations, degrees of chlorophyll destruction were similar. Over all experiments degrees of destruction were generally high and variable at low ingestion rates (<50 ng chl mg(-1) h(-1)), decreasing to a limit of about 45% at higher ingestion rates. The relationship between ingestion rate and degree of chlorophyll destruction was not obviously affected by differences in in situ conditions (e.g. stage of the spring bloom). Filtration rates, by contrast, did vary, decreasing in the presence of an apparently noxious food (Phaeocystis) and sometimes increasing during experiments, perhaps in response to increasing hunger. Faecal pellets, collected from copepods fed at natural food concentrations, did not leak pigment over a 4 d period, and neither chlorophyll nor phaeopigment was lost as copepods with food in their guts were allowed to defecate for 3 h in filtered seawater. These results suggest that most chlorophyll destruction occurs at an early stage of feeding, and that phaeopigments are not intermediates. When we assumed in a simple model that the 'bleaching' reaction was enzymatically mediated, we found that enzyme activity varied linearly with initial ingestion rate, with a positive y-intercept. One interpretation of this is that there are 2 pools of enzyme activity: one associated with the copepods and the other with the phytoplankton. The algal enzymes are normally latent, but are activated by the physical break-up of cells during ingestion. At low ingestion rates the copepod enzyme can destroy all, or most, of the ingested chlorophyll, whereas at higher ingestion rates more of the destruction is due to the algal enzymes. The high variability in degrees of chlorophyll destruction reported here and elsewhere can be explained partly by differences between algal foods (e.g. differences in levels of the bleaching enzyme), partly by differences in copepod behaviour (e.g. effects on filtration rates), and partly by differences in experimental conditions, which affect the range of ingestion rates exhibited during an incubation (e.g. density of copepods, duration of incubation).
Solubilization of senescent thylakoids from rape cotyledons in the presence of Triton X-100 was employed to establish an in vitro system that allowed the assessment of enzymatic conversion of phaeophorbide a into an uncoloured fluorescent chlorophyll catabolite, Bn-FCC-2. The action of the putative dioxygenase responsible for the cleavage of the porphyrin macrocycle depends on reduced ferredoxin as reductant. Apart from this thylakoidal catalyst, stromal protein is also required for the production of FCC-2 in vitro. The cleavage reaction does not occur with phaeophorbide b as substrate. Saturation kinetics with phaeophorbide a as substrate yielded an apparent Km-value of c. 200 μ. The enzyme contains iron as suggested by inhibitory effects of appropriate chelators. Enzyme activity lost upon treatment with bipyridyl was partly restored in the presence of Fe-ions; other metal ions such as Cu, Zn and Co were ineffective. The enzyme is absent in the thylakoids of mature green cotyledons. It appears upon the induction of foliar senescence and reaches the highest levels towards the end of the yellowing process.
The extraction and isolation procedures of twenty nickel porphyrins (seven alkylporphyrins, thirteen carboxylic acids) from lacustrine Messel shale (Eocene, Germany), as well as the unequivocal structural assignments (obtained using 200 and 400 MHz nuclear magnetic resonance (NMR), nuclear Overhauser effect, mass spectrometry and total or partial synthesis of six reference compounds) are described. Ten porphyrins could be specifically correlated with biological precursors: algal chlorophyll c (4), bacteriochlorophylls d (3) and heme (3), while the remaining ones may arise from several chlorophylls. The structures of these fossil pigments mostly confirm the classical "Treibs scheme," including the origin of some porphyrins from nonchlorophyll sources. They also show that, even in a very immature sediment, deep modifications occur, including, in particular, extensive degradation of chlorophyll E ring. The composition of the porphyrin fractions of Messel oil shale was also studied as a function of depth. A porphyrin acids/alkylporphyrins ratio varying from 0.35 to 24.8 demonstrated that the apparent homogeneity of the shale is not reflected on the molecular scale. This was confirmed when the abundance of the twenty individual porphyrins of known structure was measured along the core. Significant correlations between individual porphyrins were found: fossils of bacteriochlorophylls d , homolog pairs of porphyrins (3-H/3-ethyl), etc.
A series of non-polar chlorophyll degradation products (NPCs) with greater than 10 components has been isolated from Black Sea sediment and identified as pyropheophorbide steryl esters by visible and mass spectrometry. These compounds have been previously observed in seawater and sediment trap samples, and may be formed during grazing of phytoplankton by zooplanktonic herbivores. In Black Sea sediments, NPCs constitute 14% of the total phorbins determined spectroscopically at 660 nm, and 39% of the total chlorophyll degradation products measured by high pressure liquid chromatography. NPCs therefore constitute a significant sedimentary sink for chlorophyll. The distribution of sterols released by hydrolysis of NPCs most closely resembles sterols in suspended particulate matter collected from the euphotic zone and is quite different from the distribution of solvent-extractable sterols in sediments. Sterols extracted from sediments have high concentrations of 4-methylsterols and high stanol/stenol ratios. NPC-derived sterols have very low concentrations of 4-methylsterols and low stanol/stenol ratios. We suggest that these differences reflect an enhanced preservation of NPCs in sediments relative to free sterols and phorbins. As a result, the original production of sterols in the euphotic zone may be more closely approximated by the distribution of NPC-derived sterols than by the distribution of free sterols in sediments.
In a study of the biochemical aspects of the decomposition of chlorophyll, measurement of the activity of the enzyme chlorophyllase in marine phytoplankton was attempted in vitro by observing the conversion of chlorophyll to chlorophyllide. Our experiments indicate that in darkness and at room temperatures any enzymatic activity, if present, is immeasurable by the techniques employed.As a consequence, we have considered the photo-bleaching of chlorophyll as a possible means of decomposition. This has been identified as a photo-oxidation and the decomposition of the pigment is extremely rapid. Our experiments show that a similar photo-oxidation exists in fractured cells and degraded pigments found in the feces of marine herbivores. Although the rate of photo-bleaching is slower in vivo than in vitro, we postulate that this is a principle mechanism for pigment decomposition.
Monoalgal cultured Eutreptielia gymnastica contained chlorophyll a and b. The acetylenic carotenoids diatoxanthin and diadinoxanthin were among the main xanthophylls while their non-acetylenic analogues zeaxanthin and antheraxanthin were absent. The structurally most complex carotenoid was identical with neoxanthin. Three of the xanthophylls isolated could not be positively correlated with carotenoids previously reported from the Euglenophyceae. The ketocarotenoids astaxanthin, canthaxanthin and echinenone were absent.
A convenient, large-scale method for separation of the aand b series metal-free chlorophyll derivatives is described, utilising the Girard ‘T’ reagent with subsequent chromatography. Efficient procedures for conversion of phaeophytin-a(3) into rhodoporphyrin-XV dimethyl ester (1) and the corresponding 2-vinyl compound (2), involving the classical oxidation to purpurin derivatives, followed by further degradation, are described: n.m.r. data for several important chlorophyll degradation products are reported. Novel oxidative reactions of the isocyclic ring in methyl mesopyrophaeophorbide-a(19) are also described.
A reverse-phase high-performance liquid chromatographic (h.p.l.c.) system is developed for a rapid (≈ 20 min) separation and quantification of fourteen chlorophylls and their breakdown products and seventeen carotenoids from acetone extracts of algal cultures and natural waters. An ion-pairing reagent is included to achieve good resolution with the acidic chloropigments (chlorophyllides and phaeophorbides). Fluorescence and absorbance detectors are used to quantify chloropigments and carotenoids respectively, with detection limits of 0.01–0.2 ng for these pigments and 200–600 ng for carotenoids. Chlorophyll a at concentrations of 0.1 ng l−1 may be detected in sea water. Methanol is shown to be unsuitable for extracting pigments because it causes allomerization and transesterification of chlorophylls and chlorophyllides. The spectrophotometric determination of chlorophyll pigments in samples containing breakdown products grossly overestimates the actual concentration of these pigments, as determined by h.p.l.c.
Jn laboratory grazing cxperimcnts, primarily with Cabanus sp. feeding on Coscinodiscus angstii, the decrease in chlorophyll concentration and the increase in phcophorbidc con- centration was determined. The average conversion of chlorophyll to pheophorbidc was GS% on a weight basis and 100% on a molar basis. Some chlorophyll was found in fecal pellets. The specific absorption coefficient of pheophorbide in 90% acetone at G67 nm was 53.5 (g-cm)-l, about the same as that of pheophytin under the same conditions. Pre- viously published equations For the determination of pheophytjn can be used for pheo- phorbide. Chlorophyll degradation products are usually measured in an attempt to obtain accurate chlorophyll estimates, since these relatively common compounds have ab- sorption and emission spectra similar to that of chlorophyll. The routine measure- ment of degradation products, either by fluoromctry (IIolm-Hansen et al. 1965) or spectrophotometry ( Moss 1967a,b; Loren- zen 1967a), has stimulated interest in their distribution and mode of formation and destruction in the ocean. These degrada- tion products originate through zooplank- ton grazing (Currie 1962). Nemoto ( 1968, 1972) and Nemoto and Saijo (1968) mea- sured pigment levels in the guts of various zooplankton species, but did not attempt to relate these values to the nature and amount of plant material originally in- ges ted. The degradation of chlorophyll occurs by the following pathways (Yentsch 1967):
The vertical distribution of chlorophyll and phaeo-pigments were studied off Baja California. Concentrations of both increased with depth until a maximum was reached below which lower levels were observed. The chlorophyll maximum was usually near the base of the euphotic zone, in the thermocline. The phaeo-pigment maximum either coincided with the chlorophyll maximum or was at a slightly greater depth.The phaeo-pigment maximum coincided with that portion of the water column where nutrients increased in concentration. This layer possibly represents an accumulation of detritus, and an area where remineralization and lower re-utilization of nutrients occur.Phaeo-pigments are readily produced by zooplankters grazing on phytoplankton. A relationship exists between the number of zooplankters in the water column and the quantity of phaeo-pigments in the euphotic zone. Phaeo-pigments in the euphotic zone may be indicative of the past history of grazing activity in the water column, and may also be a measure of nutrient turnover.
Concentrations and fluxes of chlorophyll and carotenoid pigments were measured in suspended and settling particulate matter and in surface sediments in Lake Mendota. Flux comparisons were used to calculate the extent of alteration or degradation within the water column and at the sediment surface. Losses within the water column for specific time intervals ranged from almost negligible for diatoxanthin to 96% for peridinin. The extent of loss was influenced by pigment type and transport process.
Surface sediment diagenesis in Lake Mendota resulted in differential degradation rates among chlorophyll and carotenoid constituents. Deposition of pheophorbide a —a grazing indicator—was most important during late spring, as zooplankton populations increased and chlorophyll levels in the water column dropped below 1 nmol liter ⁻¹ . The ability to trace the magnitude of this annual event through the sedimentary record was obscured by selective degradation of pheophorbide relative to chlorophyll and pheophytin. Similarly, carotenoid composition was dramatically altered both within the water column and at the sediment surface. Fucoxanthin and peridinin, major water‐column carotenoids, were degraded extensively before incorporation in the sediments.
Copepods and seawater were collected during spring bloom conditions off southwest Nova Scotia and the east coast of Newfoundland, Canada. The copepods were starved for 12 or 24 h and then fed with screened seawater. High pressure liquid chromatography (HPLC) was used to measure the concentrations of chlorophylls a and c (and derived phaeopigments), fucoxanthin and diadinoxanthin in the incubation medium both before and after grazing, and in purified samples of faecal pellets collected after grazing. Close to 100 % of ingested chlorophylls a and c did not survive digestion by copepods. Virtually no phaeophorbide a or phaeophytin a were produced but instead one or both of their pyrolised derivatives. A pyrolised phaeoporphyrin c derivative was apparently also produced. Fucoxanthin was completely broken down during digestion, but some or all may have been converted to a less polar unidentified derivative. Some ingested diadinoxanthin sometimes appeared intact in faecal pellets. The conversion efficiency of chlorophyll a to pyrophaeopigment a was not usually 100 %, but ingested chlorophyll a was less extensively destroyed than either chlorophyll c or diadinoxanthin. The degree of destruction for the 3 pigments varied in parallel and when it was relatively low the only fluorescent components found in faecal pellets, in appreciable amounts, were chlorophylls a and c and the 3 pyrophaeopigments. When the degree of pigment destruction was high, a number of unidentified fluorescent components were also present in faecal pellets, which were probably the products of more extensive chlorophyll degradation.
Pigment abundances of the oxygenic and anoxygenic photoautotrophic communities from sediments and the water column in Lake Okeechobee, Florida, were estimated using reverse-phase high-performance liquid chromatographic (RP-HPLC) and photodiode array (PDA) UV/VIS (350-800 nm) spectrophotometric analyses. Thirty lipophilic pigments were identified and measured in the samples, with the most abundant overall (sediment and open-water samples combined) being chlorophyll a (38.1%), fucoxanthin (12.6%), pheophytin a (7.6%), zeaxanthin (6.6%), and pyropheophytin a (3.6%). Relative abundance of chlorophyll a was greater in the water column than in the sediments (58.3 versus 24.3% of all pigments) whereas pheophytin a comprised 9.1% of the total pigments in the sediments but only 3.7% of the total pigments in the water column. Principal component analysis (PCA) separated the sediment samples from those collected in the water column; this discrimination appears to be a function of pigment integrity in that sediment assemblages had much greater relative abundances of degraded pigments. Different regions of the lake were weakly separated by PCA based on pigments. The relatively weak degree of separation may reflect the overwhelming abundance of chlorophyll a at all sites. Overall, the pigment assemblage in Lake Okeechobee suggests cyanobacteria-diatom dominance. Out of 65 sampling events, pigments from anoxygenic photoautotrophs (e.g., bacteriochlorophylls) were detected 17 times but accounted for >20% of total chlorophyll only five times. Bacteriochlorophylls were observed only in the sediments and were most abundant during June and September, when winds were calm and temperatures warm, and at relatively shallow sites.
132,173-Cyclopheophorbide enol (I) a chlorophyll A deriv. without a metal ion was isolated from Darwinella oxeata and its structure was detd. by phys. and X-ray measurements. [on SciFinder(R)]
The importance of algae, both as a contribution to the understanding of living things and in practical terms, hardly needs stressing today. Despite the previous emphasis on photosynthesis research in land plants there is now a large corpus of work on algae. This chapter intends to bring much of the dispersed literature together, so as to achieve an integrated framework from which conclusions can be drawn to further stimulate research. Organisms from the borderline of groups loosely called prokaryotes, plants, and animals have been discussed along with how the majority of algae are influenced by the light climate properties. The structure and function of the photosynthetic membrane have been described. Various kinds and levels of light harvesting available to algae are reviewed briefly. A more detailed analysis of some biochemical and biophysical aspects of light harvesting are also given. Light is essential to all photosynthetic autotrophs. But it is only to the extent that light is limiting to growth that light-harvesting strategies become important. It is therefore necessary to consider under what conditions light does become limiting for algal growth. Strategies of light harvesting are discussed in terms of general ecological, taxonomic, morphological, and cytological aspects. The chapter looks into photosynthetic pigments, reaction centre complexes, and pigment protein (light-harvesting) complexes with details of the principles of light harvesting in light of quantum chemistry and transfer of excitation energy, structure and function, distribution of excitation energy between the photosystems, and interaction of the light-harvesting apparatus with other photosynthetic processes.
Chlorophyll-oxidase in barley thylakoids was activated by linolenic acid. The reaction products from endogenous chlorophylls were investigated by thin layer and high performance liquid chromatography. Within 2-10 min a new pigment was formed which migrated identically with authentic 13(2)-hydroxychlorophyll a (1a). After reaction with methanolic acid, the reaction product was identified as 13(2)-hydroxymethylpheophorbide (1b) by high performance thin layer and liquid chromatography.