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Resonance Raman spectra in the 1130–1560 cm⁻¹ region at 77 K of a violaxanthin and vaucheriaxanthin in n-hexane, excited at 476.5 nm, and b VCP excited at 488.0, 496.5, 501.7, 514.5, and 528.7 nm
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Resonance Raman spectroscopy was used to evaluate pigment-binding site properties in the violaxanthin--chlorophyll-a-binding protein (VCP) from Nannochloropsis oceanica. The pigments bound to this antenna protein are chlorophyll-a, violaxanthin, and vaucheriaxanthin. The molecular structures of bound Chl-a molecules are discussed with respect to th...
Citations
... However, the proportion of qE or qZ contributions is going to vary depending on the species 40 . In order to implement a similar model of NPQ for use in vascular plants, more components need to be incorporated such as quenching due to lutein and state transitions [5][6][7] , which are not present in N. oceanica. However, we believe the model presented here provides a basis for building a quantitative model of NPQ responses for plants and other photosynthetic organisms, which are mediated by the same xanthophyll cycle. ...
Efficiently balancing photochemistry and photoprotection is crucial for survival and productivity of photosynthetic organisms in the rapidly fluctuating light levels found in natural environments. The ability to respond quickly to sudden changes in light level is clearly advantageous. In the alga Nannochloropsis oceanica we observed an ability to respond rapidly to sudden increases in light level which occur soon after a previous high-light exposure. This ability implies a kind of memory. In this work, we explore the xanthophyll cycle in N. oceanica as a short-term photoprotective memory system. By combining snapshot fluorescence lifetime measurements with a biochemistry-based quantitative model, we show that short-term memory arises from the xanthophyll cycle. In addition, the model enables us to characterize the relative quenching abilities of the three xanthophyll cycle components. Given the ubiquity of the xanthophyll cycle in photosynthetic organisms the model described here will be of utility in improving our understanding of vascular plant and algal photoprotection with important implications for crop productivity.
... The xanthophyll cycle in N. oceanica is a shared feature with higher plants, but this organism lacks more complex features like state transitions or pigments like lutein and chlorophyll-b. [5][6][7] The simplistic nature make N. oceanica an ideal model organism for studying the essential components of NPQ. ...
... Evidence for zeaxanthin-dependent but LHCX1-independent "qZ" quenching has also been found, although its contribution to NPQ appears to be much smaller than that of LHCX1-dependent "qE" quenching. In order to implement a similar model of NPQ for use in vascular plants, more components need to be incorporated such as quenching due to lutein and state transitions, [5][6][7] which are not present in N. oceanica. However, we believe the model presented here provides a basis for building a quantitative model of plant NPQ responses, which are mediated by the same xanthophyll cycle. ...
Efficiently balancing photochemistry and photoprotection is crucial for survival and productivity of photosynthetic organisms in the rapidly fluctuating light levels found in natural environments. The ability to respond quickly to sudden changes in light level is clearly advantageous. In the alga Nannochloropsis oceanica we observed an ability to respond rapidly to sudden increases in light level which occur soon after a previous high-light exposure. This ability implies a kind of memory. In this work, we explore the xanthophyll cycle in N. oceanica as a photoprotective memory system. By combining snapshot fluorescence lifetime measurements with a biochemistry-based quantitative model we show that both short-term and medium-term "memory" arises from the xanthophyll cycle. In addition, the model enables us to characterize the relative quenching abilities of the three xanthophyll cycle components. Given the ubiquity of the xanthophyll cycle in photosynthetic organisms the model described here will be of utility in improving our understanding of vascular plant photoprotection with important implications for crop productivity.
... [140] However, a large proportion of released canthaxanthin was selectively distributed in the continuous phase rather than transferred into the micelle phase, further reducing their bioaccessibility. [141] Moreover, the xanthophylls violaxanthin was significantly more bioaccessible than all-trans-β-carotene. [136] Violaxanthin is a hydrophobic molecule commonly associated with membranes and/or involved in non-covalent binding to a specific light-harvesting protein, violaxanthin-chlorophyll (VCP), [142] which impacts their bioaccessibility negatively. Nevertheless, few articles focus on its bioaccessibility due to the protein-binding property of peridinin, [143] which can be considered a future research direction. ...
In recent years, carotenoids, as photosynthetic pigments, have drawn increasing interest due to their health benefits. This is because carotenoids have possessed enormous potential in lowering the risk of cardiovascular, cataracts, macular degradation and malignant tumours. Although many carotenoids can be produced via chemical synthesis, the commonly used petroleum-derived extraction method can be problematic for the environment and potentially contaminate the isolated carotenoids. Therefore, in contrast to chemosynthesis, microalgae can be considered an excellent alternative natural source to synthetic ones. Varying in microalgal strains, a variety of different carotenoids can be produced, for instance, the β-carotene from Dunaliella salina, the fucoxanthin from Undaria pinnatifida and the astaxanthin from Haematococcus pluvialis. Besides, the pharmacological action of carotenoids is highly associated with their bioaccessibility and bioavailability, which is one of the research directions and affecting factors of the carotenoid application in the food, pharmaceutical, nutraceutical and cosmeceutical industries. Despite there being numerous publications about carotenoids, a comprehensive review on the microalgal carotenoids and their triggered bioactivities is still lacking. Considering the significance of bioavailability, this review presents extensive information on microalgal carotenoids, including their classifications, bioaccessibilities, absorption process mechanisms, bioactivities and relevant health benefits.
... Overexpressed PtCRTISO4 enhances the violaxanthin contents of Nannochloropsis oceanica Different with other photosynthetic eukaryotes, the predominant light harvesting complex of Nannochloropsis is violaxanthin-chlorophyll a binding protein (VCP), which binds abundant violaxanthin and minor vaucheriaxanthin as well as traces of zeaxanthin and antheraxanthin (Kean et al., 2016;Llansola-Portoles et al., 2017). The unique photosynthetic apparatus of Nannochloropsis underlies its peculiar pigment composition featured by extraordinarily high ratio of violaxanthin. ...
... Vaucheriaxanthin is another key member of VCP, of which the molecules accommodated into the antenna complex are less than the violaxanthin but more than the zeaxanthin and antheraxanthin. However, vaucheriaxanthin is mainly present in the form of vaucheriaxanthin acyl esters (one of the chemotaxonomic markers of Eustigmatophyta) rather than free pigment (Stefania et al., 2014;Llansola-Portoles et al., 2017). In this study, the contents of vaucheriaxanthin acyl esters were failed to be determined due to the absence of standards. ...
Nannochloropsis has been considered as a promising feedstock for the industrial production of violaxanthin. However, a rational breeding strategy for the enhancement of violaxanthin content in this microalga is still vacant, thereby limiting its industrial application. All- trans -lycopene locates in the first branch point of carotenogenesis. The carotenoid isomerase (CRTISO), catalyzing the lycopene formation, is thus regarded as a key enzyme for carotenogenesis. Phaeodactylum tricornutum can accumulate high-level carotenoids under optimal conditions. Therefore, it is feasible to improve violaxanthin level in Nannochloropsis by overexpression of PtCRTISO . Protein targeting analysis of seven PtCRTISO candidates (PtCRTISO1–6 and PtCRTISO-like) demonstrated that PtCRTISO4 was most likely the carotenoid isomerase of P . tricornutum . Moreover, the transcriptional pattern of PtCRTISO4 at different cultivation periods was quite similar to other known carotenogenesis genes. Thus, PtCRTISO4 was transformed into N . oceanica . Compared to the wild type (WT), all three transgenic lines (T1–T3) of N . oceanica exhibited higher levels of total carotenoid and violaxanthin. Notably, T3 exhibited the peak violaxanthin content of 4.48 mg g –1 dry cell weight (DCW), which was 1.68-folds higher than WT. Interestingly, qRT-polymerase chain reaction (PCR) results demonstrated that phytoene synthase ( NoPSY ) rather than ζ-carotene desaturase ( NoZDS ) and lycopene β-cyclase ( NoLCYB ) exhibited the highest upregulation, suggesting that PtCRTISO4 played an additional regulatory role in terms of carotenoid accumulation. Moreover, PtCRTISO4 overexpression increased C18:1n-9 but decreased C16:1n-7, implying that C18:1 may serve as a main feedstock for xanthophyll esterification in Nannochloropsis . Our results will provide valuable information for the violaxanthin production from Nannochloropsis .
... The major LHC from higher plants, the trimeric protein LHCII, binds 14 Chls (8 Chls-a and 6 Chls-b) and 4 carotenoid molecules (2 non-equivalent luteins, 1 9′-cis neoxanthin (Neo) and 1 violaxanthin or zeaxanthin) per monomer [3]. Land plants share the same photosynthetic pigment-protein system, while algae have developed a variety of light-harvesting systems, reflecting both the diversity of their origin and the variety of their light environments [4][5][6]. Major carotenoids for light-harvesting in marine algae are the allenic xanthophylls fucoxanthin (Fx) and peridinin (Per), the former mainly in brown algae and diatoms [7][8][9], and the latter in dinoflagellates [10]. Antenna proteins in both cases (fucoxanthin-chlorophyll-protein, FCP, and peridinin-chlorophyll-protein, PCP, respectively) bind carotenoids at higher relative stoichiometries [9] in order to increase the ability of these organisms to harvest photons in the blue-green range [11,12]. ...
The siphonaxanthin-siphonein-chlorophyll-a/b-binding protein (SCP), a trimeric light-harvesting complex isolated from photosystem II of the siphonous green alga Codium fragile, binds the carotenoid siphonaxanthin (Sx) and/or its ester siphonein in place of lutein, in addition to chlorophylls a/b and neoxanthin. SCP exhibits a higher content of chlorophyll b (Chl-b) than its counterpart in green plants, light-harvesting complex II (LHCII), increasing the relative absorption of blue-green light for photosynthesis. Using low temperature absorption and resonance Raman spectroscopies, we reveal the presence of two non-equivalent Sx molecules in SCP, and assign their absorption peaks at 501 and 535 nm. The red-absorbing Sx population exhibits a significant distortion that is reminiscent of lutein 2 in trimeric LHCII. Unexpected enhancement of the Raman modes of Chls-b in SCP allows an unequivocal description of seven to nine non-equivalent Chls-b, and six distinct Chl-a populations in this protein.
... At 1000 cm −1 , the ν 3 band arises from in-plane rocking vibrations of the methyl groups attached to the conjugated chain, coupled with in-plane bending modes of the adjacent C-H's (38). It was recently shown to be a fingerprint of the conjugated end-cycle configuration (45,46) and sensitive to the presence of a conjugated allene group (47,48). Finally, the ν 4 band, around 960 cm −1 , arises from C-H out-ofplane wagging motions coupled with C=C torsional modes (38). ...
When plants are exposed to high-light conditions, the potentially harmful excess energy is dissipated as heat, a process called non-photochemical quenching. Efficient energy dissipation can also be induced in the major light-harvesting complex of photosystem II (LHCII) in vitro, by altering the structure and interactions of several bound cofactors. In both cases, the extent of quenching has been correlated with conformational changes (twisting) affecting two bound carotenoids – neoxanthin, and one of the two luteins (in site L1). While this lutein is directly involved in the quenching process, neoxanthin senses the overall change in state without playing a direct role in energy dissipation. Here we describe the isolation of an intermediate state of LHCII, using the detergent n-dodecyl-α-D-maltoside, which exhibits the twisting of neoxanthin (along with changes in chlorophyll-protein interactions), in the absence of the L1 change or corresponding quenching. We demonstrate that neoxanthin is actually a reporter of the LHCII environment – probably reflecting a large-scale conformational change in the protein – while the appearance of excitation energy quenching is concomitant with the configuration change of the L1 carotenoid only, reflecting changes on a smaller scale. This unquenched LHCII intermediate, described here for the first time, provides for a deeper understanding of the molecular mechanism of quenching.
... In particular, Nannochloropsis oceanica, a green microalga with a spherical-oval form and a smooth and rigid cell wall, is well-known for its pigment composition, including chlorophyll a and carotenoids such as violaxanthin, vaucheriaxanthin, and -carotene, among others [4]. Some of these pigments have been reported in the N. oceanica light-harvesting complex (LHC) system, named violaxanthin-chlorophyll a protein (VCP), which plays an important role in photosynthesis [5][6][7]. Besides their importance as essential components of its photosynthetic apparatus, some of these pigments, particularly carotenoids, have been associated with many biological activities, such as UV-protective [8], anti-inflammatory [9] or antiproliferative effects [10]. ...
In this study, the recovery of different bioactive compounds from Nannochloropsis oceanica biomass is proposed using high and ultra-high pressure-based processes. The effect of different pretreatments to weaken cell wall was evaluated before pressurized liquid extraction (PLE). PLE was optimized using an experimental design with ethanol as extraction solvent. Optimum extraction conditions were found at 57 °C and 3 extraction cycles, providing a total carotenoids content of 115.1 ± 0.6 mg/g extract. Then, the residual biomass was extracted using limonene, and an enriched-lipid fraction was obtained. In parallel, ultra-high pressure extraction (UHPE) was applied directly to dry biomass to simultaneously disrupt the cell wall and extract the valuable compounds. Results showed that UHPE technique did not improve carotenoids extraction compared to PLE, although the recovery of polyunsaturated fatty acids was significantly better. Moreover, extracts were chemically characterized using high-performance liquid chromatography detection and gas chromatography coupled to mass spectrometry detection.
... Clustered regularly interspaced short palindromic repeats (CRISPR)-based gene editing techniques have also been successfully employed in targeted gene disruption (Wang et al., 2016;Verruto et al., 2018;Poliner et al., 2018c;Naduthodi et al., 2019), leading to improved lipid production in Nannochloropsis species (Ajjawi et al., 2017). Notably, the development of approaches based on single-cell Raman spectra that characterize the profiles of energy storage molecules in N.oceanica, the 'ramanome', has accelerated the time-consuming microalgal phenotyping processes (Ji et al., 2014;Wang et al., 2014b;He et al., 2017;Llansola-Portoles et al., 2017) by unveiling and sorting single-cell-level phenomes in a label-free, non-invasive manner (Wang et al., , 2020Jing et al., 2018;He et al., 2019). ...
The unicellular industrial oleaginous microalgae Nannochloropsis spp. are model organisms for microalgal systems and synthetic biology. To facilitate community‐based annotation and mining of the rapidly accumulated functional genomics resources, we have initiated an international consortium and present a comprehensive, multi‐omics resource database named Nannochloropsis Design and Synthesis (NanDeSyn; http://nandesyn.single-cell.cn). Via the Tripal toolkit, it featured user friendly interfaces hosting genomic resources with gene annotations, and transcriptomic and proteomic data for six Nannochloropsis species, including two updated genomes of N. oceanica IMET1 and N. salina CCMP 1776. Toolboxes for search, Blast, synteny view, enrichment analysis, metabolic pathway analysis, genome browser, etc. were also included. In addition, functional validation of genes was indicated based on phenotypes of mutants and relevant bibliography. Furthermore, epigenomic resources were also incorporated, especially for small RNA‐Seq including miRNAs and circRNAs. Such comprehensive and integrated landscapes of Nannochloropsis genomics and epigenomics will promote and accelerate community efforts in systems and synthetic biology of these industrially important microalgae.
... The largest VCP oligomers were present in zones Z5 and Z6 (B9 and B10) (Fig. 3b), co-purifying with the photosystems. Presence of PSII core just above band B7 helps to estimate its apparent mass about 300 kDa, using the estimate of the PSII monomer mass given by Zouni et al. (2005), which implies ~ 10 LHC subunits (assuming mass of VCP monomer apoprotein of approximately 20 kDa and the pigment complement according to Llansola-Portoles et al. (2017) adding another 10 kDa for a total VCP monomer mass 30 kDa). Here the PSII is assumed to be monomeric based on observation of N. oceanica (Bína et al. 2017a, b). ...
Survival of phototrophic organisms depends on their ability to collect and convert enough light energy to support their metabolism. Phototrophs can extend their absorption cross section by using diverse pigments and by tuning the properties of these pigments via pigment–pigment and pigment–protein interaction. It is well known that some cyanobacteria can grow in heavily shaded habitats by utilizing far-red light harvested with far-red-absorbing chlorophylls d and f. We describe a red-shifted light-harvesting system based on chlorophyll a from a freshwater eustigmatophyte alga Trachydiscus minutus (Eustigmatophyceae, Goniochloridales). A comprehensive characterization of the photosynthetic apparatus of T. minutus is presented. We show that thylakoid membranes of T. minutus contain light-harvesting complexes of several sizes differing in the relative amount of far-red chlorophyll a forms absorbing around 700 nm. The pigment arrangement of the major red-shifted light-harvesting complex is similar to that of the red-shifted antenna of a marine alveolate alga Chromera velia. Evolutionary aspects of the algal far-red light-harvesting complexes are discussed. The presence of these antennas in eustigmatophyte algae opens up new ways to modify organisms of this promising group for effective use of far-red light in mass cultures.
... As an in vivo proof-of-concept study, we performed snapshot Car S 1 ESA TA measurements on live cells of an alga, Nannochloropis oceanica. N. oceanica appears to be an ideal sample for snapshot TA given that is smaller (2-3 μm) than other model algae (Vieler et al. 2012) and it possesses a simple pigment composition (Llansola-Portoles et al. 2017). These factors result in suppressed pump scattering and less spectrally overlapping signals, respectively. ...
Although the importance of nonphotochemical quenching (NPQ) on photosynthetic biomass production and crop yields is well established, the in vivo operation of the individual mechanisms contributing to overall NPQ is still a matter of controversy. In order to investigate the timescale and activation dynamics of specific quenching mechanisms, we have developed a technique called snapshot transient absorption (TA) spectroscopy, which can monitor molecular species involved in the quenching response with a time resolution of 30 s. Using intact thylakoid membrane samples, we show how conventional TA kinetic and spectral analyses enable the determination of the appropriate wavelength and time delay for snapshot TA experiments. As an example, we show how the chlorophyll-carotenoid charge transfer and excitation energy transfer mechanisms can be monitored based on signals corresponding to the carotenoid (Car) radical cation and Car S1 excited state absorption, respectively. The use of snapshot TA spectroscopy together with the previously reported fluorescence lifetime snapshot technique (Sylak-Glassman et al. in Photosynth Res 127:69–76, 2016) provides valuable information such as the concurrent appearance of specific quenching species and overall quenching of excited Chl. Furthermore, we show that the snapshot TA technique can be successfully applied to completely intact photosynthetic organisms such as live cells of Nannochloropsis. This demonstrates that the snapshot TA technique is a valuable method for tracking the dynamics of intact samples that evolve over time, such as the photosynthetic system in response to high-light exposure.
