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Antibacterial potential of ??-linolenic acid from Fischerella sp. colonizing Neem tree bark
Abstract
Pharmaceutically important γ-linolenic acid (GLA) was produced (4.1mgg−1 dry wt) by laboratory grown cyanobacterium Fischerella sp. colonizing Neem (Azadirachta indica) tree bark. GLA isolated from the test cyanobacterium was active against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25992, Salmonella typhi (local strain), Pseudomonas aeruginosa ATCC 27853 and Enterobacter aerogenes MTCC 2822. The overproduction of GLA was also monitored by altering phosphate and nitrate levels in the nutrient medium.
A doubling in phosphate concentration (58μM) increased GLA level up to 12% over that of control cells while half of this phosphate level reduced GLA synthesis by 8%.
In contrast, elevated nitrate concentrations (5 and 10mM) stimulated biomass yield but not GLA, as the levels approximated
to the nitrate-lacking control. The antibacterial potential of GLA from Fischerella sp. grown at varying P or N levels was at variance as evidenced by the diameter of inhibition zones against S. aureus. This variation in inhibition zones reflected differing levels of GLA as ascertained quantitatively by HPLC.
... The extract of this planktonic cyanobacterium was also effective against the pathogenic Escherichia coli bacterium (Chauhan et al., 2014a,b). Further investigation on the secondary metabolites associated with cyanobacteria, active compounds such as Calothrixin A, obtained from Calothrix (Rickards et al., 1999); kawaguchipeptins A and B, extracted from Microcystis aeruginosa (Parajuli et al., 2016); Linolenic acid from Fischerella (Asthana et al., 2006); oscillapeptin from Oscillatoria margaritifera (Demay et al., 2019) were found to have good antimicrobial activity. Reports were also found on the broad-spectrum antimicrobial activity of different genera of Spirulina (Ozdemir et al., 2004;. ...
... A wide range of antifungal compounds were reported from cyanobacteria, which usually falls within peptides, polyketides, and alkaloid groups and is generally synthesized by ribosomal or nonribosomal pathways (Shishido et al., 2015). Many compounds were earlier reported as antifungals that include hassallidins, phytoalexin, Scytophycins, Tolytoxin, toyocamycin, tubercidin, nostodione, nostofungicidine, nostocyclamide, amphidinolide, carazostatin, welwitindolinones, laxaphicins, hapalindoles, fischerindole, ambiguine isonitriles, fisherellin, and tjipanazole (Moore et al., 1984;Tan, 2007;Neuhof et al., 2005Neuhof et al., , 2006Mo et al., 2009a,b;Burja et al., 2001;Asthana et al., 2006;Abed et al., 2009;Vestola et al., 2014;Tomsickova et al., 2014). The active compounds were reported from diverse genera of cyanobacteria that comprise Hassallia, Anabaena, Fischerella, Nostoc, Scytonema, Cylindrospermopsis, Aphanizomenon, Tolypothrix, Planktothrix, etc. (Neuhof et al., 2006;Asthana et al., 2006;Tomsickova et al., 2014;Vestola et al., 2014;Shishido et al., 2015). ...
... Many compounds were earlier reported as antifungals that include hassallidins, phytoalexin, Scytophycins, Tolytoxin, toyocamycin, tubercidin, nostodione, nostofungicidine, nostocyclamide, amphidinolide, carazostatin, welwitindolinones, laxaphicins, hapalindoles, fischerindole, ambiguine isonitriles, fisherellin, and tjipanazole (Moore et al., 1984;Tan, 2007;Neuhof et al., 2005Neuhof et al., , 2006Mo et al., 2009a,b;Burja et al., 2001;Asthana et al., 2006;Abed et al., 2009;Vestola et al., 2014;Tomsickova et al., 2014). The active compounds were reported from diverse genera of cyanobacteria that comprise Hassallia, Anabaena, Fischerella, Nostoc, Scytonema, Cylindrospermopsis, Aphanizomenon, Tolypothrix, Planktothrix, etc. (Neuhof et al., 2006;Asthana et al., 2006;Tomsickova et al., 2014;Vestola et al., 2014;Shishido et al., 2015). Among the said compounds, hassallidin represents an interesting antifungal compound synthesized by nonribosomal peptide synthase. ...
The taxonomic identification of cyanobacteria is essential for researchers or/and competent authorities to know their diversity and detect, manage, and control potentially toxic cyanobacteria. Microbiologists and botanists agree that polyphasic approaches are a powerful tool to identify cyanobacteria. This chapter describes the polyphasic approach, the steps to follow, and some recommendations for its correct application. The changes in taxonomy using this methodology are also explained. Finally, the applications of a polyphasic approach on genomic and metabarcoding biodiversity studies are described. The polyphasic approach is a well defined and standard tool for classifying cyanobacteria, which researchers accept, but it is continuously being revised.
... The extract of this planktonic cyanobacterium was also effective against the pathogenic Escherichia coli bacterium (Chauhan et al., 2014a,b). Further investigation on the secondary metabolites associated with cyanobacteria, active compounds such as Calothrixin A, obtained from Calothrix (Rickards et al., 1999); kawaguchipeptins A and B, extracted from Microcystis aeruginosa (Parajuli et al., 2016); Linolenic acid from Fischerella (Asthana et al., 2006); oscillapeptin from Oscillatoria margaritifera (Demay et al., 2019) were found to have good antimicrobial activity. Reports were also found on the broad-spectrum antimicrobial activity of different genera of Spirulina (Ozdemir et al., 2004;. ...
... A wide range of antifungal compounds were reported from cyanobacteria, which usually falls within peptides, polyketides, and alkaloid groups and is generally synthesized by ribosomal or nonribosomal pathways (Shishido et al., 2015). Many compounds were earlier reported as antifungals that include hassallidins, phytoalexin, Scytophycins, Tolytoxin, toyocamycin, tubercidin, nostodione, nostofungicidine, nostocyclamide, amphidinolide, carazostatin, welwitindolinones, laxaphicins, hapalindoles, fischerindole, ambiguine isonitriles, fisherellin, and tjipanazole (Moore et al., 1984;Tan, 2007;Neuhof et al., 2005Neuhof et al., , 2006Mo et al., 2009a,b;Burja et al., 2001;Asthana et al., 2006;Abed et al., 2009;Vestola et al., 2014;Tomsickova et al., 2014). The active compounds were reported from diverse genera of cyanobacteria that comprise Hassallia, Anabaena, Fischerella, Nostoc, Scytonema, Cylindrospermopsis, Aphanizomenon, Tolypothrix, Planktothrix, etc. (Neuhof et al., 2006;Asthana et al., 2006;Tomsickova et al., 2014;Vestola et al., 2014;Shishido et al., 2015). ...
... Many compounds were earlier reported as antifungals that include hassallidins, phytoalexin, Scytophycins, Tolytoxin, toyocamycin, tubercidin, nostodione, nostofungicidine, nostocyclamide, amphidinolide, carazostatin, welwitindolinones, laxaphicins, hapalindoles, fischerindole, ambiguine isonitriles, fisherellin, and tjipanazole (Moore et al., 1984;Tan, 2007;Neuhof et al., 2005Neuhof et al., , 2006Mo et al., 2009a,b;Burja et al., 2001;Asthana et al., 2006;Abed et al., 2009;Vestola et al., 2014;Tomsickova et al., 2014). The active compounds were reported from diverse genera of cyanobacteria that comprise Hassallia, Anabaena, Fischerella, Nostoc, Scytonema, Cylindrospermopsis, Aphanizomenon, Tolypothrix, Planktothrix, etc. (Neuhof et al., 2006;Asthana et al., 2006;Tomsickova et al., 2014;Vestola et al., 2014;Shishido et al., 2015). Among the said compounds, hassallidin represents an interesting antifungal compound synthesized by nonribosomal peptide synthase. ...
Metals are essential elements for life, but they are particularly necessary for photosynthetic organisms. Here, we focus on how cyanobacterial photosynthesis responds to metal constrains, with especial emphasis on copper and iron. In particular, the photosynthetic machinery requires large amounts of iron, either as free ions or in heme and iron-sulfur cofactors. In response to the limitations and bioavailability of iron, photosynthetic organisms have developed alternatives to replace iron-containing proteins. Thus, in the photosynthetic chain of most cyanobacteria, flavodoxin (a flavoprotein) replaces ferredoxin (an iron-sulfur protein) on the donor side of photosystem I under iron-limiting conditions. In addition, when copper is available, plastocyanin (a copper protein) substitutes the heme-protein cytochrome c6 in the lumen of the thylakoid as the electron carrier from cytochrome b6f to photosystem I, and in connecting the photosynthetic and respiratory chains. In each of these pairs, both proteins have developed equivalent functional areas, resulting in a functional equivalence. However, the plastocyanin/cytochrome c6 couple exhibits intriguing parallel differences in different cyanobacteria.
The ferredoxin/flavodoxin and plastocyanin/cytochrome c6 expression is precisely regulated as a function of variations in iron or copper concentrations. Recently, the system regulating the copper-dependent cytochrome c6/plastocyanin switch has been described as composed by a transcriptional factor and a protease, the latter regulating the levels of the expression factor in response to the presence of copper.
... Cyanobacteria also express antiviral properties; Asthana et al. (2006) conducted studies on the cyanobacteria Fischerella sp., which show an active action against Mycobacterium tuberculosis, Enterobacter aerogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi and Escherichia coli (Asthana et al. 2006). ...
... Cyanobacteria also express antiviral properties; Asthana et al. (2006) conducted studies on the cyanobacteria Fischerella sp., which show an active action against Mycobacterium tuberculosis, Enterobacter aerogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi and Escherichia coli (Asthana et al. 2006). ...
... Fatty acids are attracting attention as potential therapeutic antimicrobial agents due to their potency, broad spectrum of activity and the lack of classical resistance mechanisms against the actions of these compounds [9,10]. In particular, various long-chain polyunsaturated fatty acids (LC-PUFAs), which are found naturally at high levels in many marine organisms [11], have been shown to exert highly potent activity against Gram-positive bacteria, including eicosapentaenoic acid (EPA; C20:5n-3) [12,13], docosahexaenoic acid (DHA; C22:6n-3) [14][15][16][17], γ-linolenic acid (GLA; C18:3n-6) [15,[18][19][20][21] and dihomo-γ-linolenic acid (DGLA; C20:3n-6) [15]. Furthermore, LC-PUFAs deserve special consideration for topical application because they are often associated with anti-inflammatory properties, which may provide supplementary benefit during therapy [10,22,23]. ...
... The LC-PUFAs killed S. aureus rapidly with kill times similar to earlier observations for other fatty acids against this bacterium, including caprylic acid (C8:0) [33], lauric acid [34], sapienic acid (C16:1n-10) [35,36], oleic acid (C18:1n-9) [37], GLA [19] and EPA [38]. Such rapid cell death caused by the LC-PUFAs strongly suggests a cell membrane lytic mechanism of action against S. aureus, which is in line with previous studies on Gram-positive species (see review by Desbois and Smith [9]). ...
New compounds are needed to treat acne and superficial infections caused by Propionibacterium acnes and Staphylococcus aureus due to the reduced effectiveness of agents used at present. Long-chain polyunsaturated fatty acids (LC-PUFAs) are attracting attention as potential new topical treatments for Gram-positive infections due to their antimicrobial potency and anti-inflammatory properties. This present study aimed to investigate the antimicrobial effects of six LC-PUFAs against P. acnes and S. aureus to evaluate their potential to treat infections caused by these pathogens. Minimum inhibitory concentrations were determined against P. acnes and S. aureus, and the LC-PUFAs were found to inhibit bacterial growth at 32-1024 mg/L. Generally, P. acnes was more susceptible to the growth inhibitory actions of LC-PUFAs, but these compounds were bactericidal only for S. aureus. This is the first report of antibacterial activity attributed to 15-hydroxyeicosapentaenoic acid (15-OHEPA) and 15-hydroxyeicosatrienoic acid (HETrE), while the anti-P. acnes effects of the six LC-PUFAs used herein are novel observations. During exposure to the LC-PUFAs, S. aureus cells were killed within 15-30 min. Checkerboard assays demonstrated that the LC-PUFAs did not antagonise the antimicrobial potency of clinical agents used presently against P. acnes and S. aureus. However, importantly, synergistic interactions against S. aureus were detected for combinations of benzoyl peroxide with 15-OHEPA, dihomo-γ-linolenic acid (DGLA) and HETrE; and neomycin with 15-OHEPA, DGLA, eicosapentaenoic acid, γ-linolenic acid and HETrE. In conclusion, LC-PUFAs warrant further evaluation as possible new agents to treat skin infections caused by P. acnes and S. aureus, especially in synergistic combinations with antimicrobial agents already used clinically.
... Lipopeptides laxaphycin B along with laxaphycin C are obtained from species Anabaena laxa. These constituents displayed antifungal action towards C. albicans, Saccharomyces cerevisiae, Aspergillus oryzae, Penicillium notatum, and Trichophyton mentagrophytes [105]. Dahms et al. observed antifungal properties of fisherellin from Fischerella muscicola [106]. ...
The identification of new therapeutically active constituents from algae is generating growing attention due to the unique makeup of these organisms and the potential for widespread industrial use of these constituents. Recent study has concentrated on algae, which have a novel biochemical proclivity and a diverse variety of possible commercial uses, as a provider of novel biologically active constituents. The growing number of researchers are becoming interested in identifying novel physiologically active chemicals from algae, owing to its unique composition and the potential for vast commercial uses. It is very essential to identify the organisms of those species that produce bioactive secondary metabolites that could be a potential source for new drug development. A variety of constituents, such as carbohydrates, minerals, oil, proteins along with polyunsaturated fatty acids, are found in algae preparations. Additionally, biologically active constituents such as antioxidants (tocopherols or vitamin E), vitamin C and pigments (like phy-cobilins, carotenoids and chlorophylls) are found in algae preparations. These biologically active compounds possess different therapeutic properties, such as antimicrobial (antibacterial, antiviral, antifungal), antineoplastic, antioxidative and anti-inflammatory properties. They also have the potential to be used as food by humans. Algae have been discovered to be a significant source of physiologically active chemicals that may be used in a variety of goods for animals, plants, cosmetics, and medicines, among other things.
... extract showed antibacterial activity against the pathogenic strains of E. coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Salmonella typhi, and Staphylococcus aureus (Chauhan et al. 2010). Methanolic extract of Fischerella sp. was active against E. coli, Enterobacter aerogenes, P. aeruginosa, Mycobacterium tuberculosis, S. aureus, and Salmonella typhi as well as multidrug-resistant (MDR) pathogenic species of E. coli strains in in vitro assays(Asthana et al. 2006).According to the World Health Organization (WHO), Plasmodium, Trypanosoma, Leishmania, Schistosoma, and other protozoal illnesses affect more than 100 million people worldwide. Malaria and leishmaniasis treatments have failed because these parasites have developed resistance to chemicals and pharmaceuticals(Fernández- Prada et al. 2019). ...
Cyanobacteria are photosynthetic prokaryotes that have a variety of biological activities and can be used as dietary supplements. Because of its high nutritional, protein, and digestibility content, it is utilized as a meal supplement. Spirulina sp., Anabaena sp., Microcystis sp., Nostoc sp., Lyngbya sp., Oscillatoria sp., and other cyanobacteria create a wide range of secondary bioactive
metabolites with diverse biological functions. Cyanobacteria produce various physiologically active and chemically diverse compounds such as saccharides, fatty acid amides, lipopeptides, cyclic and acyclic peptides, and alkaloids. More than half of marine cyanobacteria could be used to extract bioactive compounds that can destroy cancer cells by causing apoptosis. Their effectiveness as an antiviral, antitumor, antibacterial, anti-HIV, and dietary additive is extensively documented. However, such drugs are in various phases of clinical studies, and only a few have made it to the market. This chapter examines the bioactive chemicals in cyanobacteria with antiprotozoal, antibacterial, anti-inflammatory, anticancer, antioxidant, and antiviral properties.
... Various lipids have been isolated from cyanobacteria having antibacterial activities, such as Lyngbyoic acid, doscadenamide A, and pitinoic acid A as quorum sensing inhibitors in Pseudomonas aeruginosa (Carpine and Sieber, 2021) γ-linolenic acid (GLA), a potent antibacterial from Fischerella sp., was active against Staphylococcus aureus (Asthana et al., 2006). A lipid 2-Hydroxyethyl-11-hydroxyhexadec-9-enoate isolated from Lyngbya sp. is also effective against Methicillin-Resistant Staphylococcus aureus (MRSA). ...
Cyanobacterial species are ancient photodiazotrophs prevalent in freshwater bodies and a natural reservoir of many metabolites (low to high molecular weight) such as non-ribosomal peptides, polyketides, ribosomal peptides, alkaloids, cyanotoxins, and isoprenoids with a well-established bioactivity potential. These metabolites enable cyanobacterial survival in extreme environments such as high salinity, heavy metals, cold, UV-B, etc. Recently, these metabolites are gaining the attention of researchers across the globe because of their tremendous applications as antimicrobial agents. Many reports claim the antimicrobial nature of these metabolites; unfortunately, the mode of action of such metabolites is not well understood and/or known limited. Henceforth, this review focuses on the properties and potential application, also critically highlighting the possible mechanism of action of these metabolites to offer further translational research. The review also aims to provide a comprehensive insight into current gaps in research on cyanobacterial biology as antimicrobials and hopes to shed light on the importance of continuing research on cyanobacteria metabolites in the search for novel antimicrobials.
... including Salmonella typhimurium (Asthana et al. 2006;Desbois, Mearns-spragg, and Smith 2009). The anti-inflammatory ability of omega-3 PUFAs has also been confirmed. ...
Meat constitutes one the main protein sources worldwide. However, ethical and health concerns have limited its consumption over the last years. To overcome this negative impact, new ingredients from natural sources are being applied to meat products to obtain healthier proteinaceous meat products. Algae is a good source of unsaturated fatty acids, proteins, essential amino acids, and vitamins, which can nutritionally enrich several foods. On this basis, algae have been applied to meat products as a functional ingredient to obtain healthier meat-based products. This paper mainly reviews the bioactive compounds in algae and their application in meat products. The bioactive ingredients present in algae can give meat products functional properties such as antioxidant, neuroprotective, antigenotoxic, resulting in healthier foods. At the same time, algae
addition to foods can also contribute to delay microbial spoilage extending shelf-life. Additionally, other algae-based applications such as for packaging materials for meat products are being explored. However, consumers’ acceptance for new products (particularly in Western countries), namely those containing algae, not only depends on their knowledge, but also on their eating habits. Therefore, it is necessary to further explore the nutritional properties of algae-containing meat products to overcome the gap between new meat products and traditional products, so that healthier algae-containing meat can occupy a significant place in the market.
... Fischerella sp. methanolic extract was active against Enterobacter aerogenes, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi, and Staphylococcus aureus as well as multidrug-resistant Escherichia coli strains in in vitro assays (Asthana et al. 2006). Some antialgal compounds and its source are listed in Table 6.2. ...
This second volume of a two-volume work reviews beneficial bioactive compounds from various microorganisms such as bacteria, fungi, cyanobacteria in plant diseases management and the postharvest management of fruits using microbial antagonists. Furthermore, it reviews the impact of climate change on food security and addressed the legal aspects of microbial biocontrol applications.
The two-volume work “Microbial Biocontrol” introduces to mechanisms of plant-microbe interactions and explores latest strategies of how microbes can be applied in biocontrol and management of plant pathogens, replacing chemical fertilizers and pesticides. The book covers different groups of microorganisms such as bacteria, fungi, but also the interplay of entire microbiomes, and reviews their specific benefits in crop growth promotion, in enhancing the plants’ tolerance against biotic and abiotic stress as well as in post-harvest management of various plant diseases. Novel tools such as CRISPR/Cas9 and microbe derived nanoparticles are also addressed besides the legal aspects of biocontrol applications.
Today, rising global population and changing climatic conditions emerge as a major challenge for agronomist farmers and researchers in fulfilling the requirements of global food production. The conventional agricultural practices utilize undistributed use of chemical fertilizers and pesticides to enhance growth and yield of agricultural products and fresh foods, but their extensive and continuous use have led to a range of negative consequences on the food quality and safety, to environment as well as to human and animal health. Microbial biocontrol applications are presented as a solution, paving the way to a sustainable agriculture in compliance with the UN Sustainable Development Goals (SDG).
... Fischerella sp. methanolic extract was active against Enterobacter aerogenes, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi, and Staphylococcus aureus as well as multidrug-resistant Escherichia coli strains in in vitro assays (Asthana et al. 2006). Some antialgal compounds and its source are listed in Table 6.2. ...
Despite the ability of microbial antagonists to control postharvest spoilage, the looking for the consistently high level of disease control using microbial antagonist after a single treatment is continuing. Furthermore, individual application of either physical methods like UVC illumination and thermotherapy or the biological or nonchemical methods such as microbial antagonists, bio-stimulants, resistance inducers, and the food additive is generally considered as safe but is not sufficient to achieve higher control of postharvest methods. Moreover, food safety and quality are ensured by the implementation of a multiple hurdle approach to manage and control growth of food-borne pathogens. Therefore, a similar model may be used in developing effective strategies for the prevention and control of postharvest fruit disease. It may be inferred that integrated approaches will be the key to success in developing safe and sustainable alternatives for efficient postharvest disease management. The proposed chapter will summarize all the postharvest disease treatments which are compatible with biocontrol agents and also will overview their mechanism of action, application methods, efficacy enhancement, and future perspectives related to this topic.
... Some microalgae strains such as C. vulgaris 012, Chlamydomonas reinhardtii 008 and Chroococcus dispersus 039 produce compounds that have been reported to exhibit significant antifungal activity against Aspergillus niger, Aspergillus fumigates, C. albicans, and C. kefyr when extracted with hexane and methanol [83]. Lipopeptides (laxaphicins B and C) obtained from Anabaena laxa have been found to possess fungicidal properties against Saccharomyces cerevisiae, Penicillium notatum, Aspergillus oryzae, Trichophyton mentagrophytes, and C. albicans [84]. ...
Microalgae and cyanobacteria (blue‐green algae) are used as food by humans.
They have gained a lot of attention in recent years because of their potential
applications in biotechnology. Microalgae and cyanobacteria are good sources
of many valuable compounds, including important biologically active compounds
with antiviral, antibacterial, antifungal, and anticancer activities.
Under optimal growth condition and stress factors, algal biomass produce
varieties of potential bioactive compounds. In the current review, bioactive
compounds production and their remarkable applications such as pharmaceutical
and nutraceutical applications along with processes involved in
identification and characterization of the novel bioactive compounds are
discussed. Comprehensive knowledge about the exploration, extraction,
screening, and trading of bioactive products from microalgae and cyanobacteria
and their pharmaceutical and other applications will open up new
avenues for drug discovery and bioprospecting.
... In addition, the lipids isolated from Chlorella sp., Coelastrella sp. and Rhodellales violacea showed obvious inhibitory effects on Staphylococcus aureus. Asthana et al. (Asthana, Srivastava, Kayastha, Nath, & Singh, 2006) extracted γ-linolenic acid (GLA) from the Fischerella sp. and found that it is active against Staphylococcus aureus, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and Enterobacter aerogenes. Among them, the effect on Staphylococcus aureus was the most significant, followed by Salmonella typhi and showing a lower inhibitory effect on Enterobacter aerogenes, which also reflects the difference in the effect of fatty acids on different bacteria. ...
Microalgae, as a photosynthetic autotrophic organism, contain a variety of bioactive compounds, including lipids, proteins, polysaccharides, which have been applied in food, medicine, and fuel industries, among others. Microalgae are considered a good source of marine lipids due to their high content in unsaturated fatty acid (UFA) and can be used as a supplement/replacement for fish-based oil. The high concentration of docosahexaenoic (DHA) and eicosapentaenoic acids (EPA) in microalgae lipids, results in important physiological functions, such as antibacterial, anti-inflammatory, and immune regulation, being also a prerequisite for its development and application. In this paper, a variety of approaches for the extraction of lipids from microalgae were reviewed, including classical and innovative approaches, being the advantages and disadvantages of these methods emphasized. Further, the effects of microalgae lipids as high value bioactive compounds in human health and their use for several applications are dealt with, aiming using green(er) and effective methods to extract lipids from microalgae, as well as develop and extend their application potential.
... Some microalgae strains such as C. vulgaris 012, Chlamydomonas reinhardtii 008 and Chroococcus dispersus 039 produce compounds that have been reported to exhibit significant antifungal activity against Aspergillus niger, Aspergillus fumigates, C. albicans, and C. kefyr when extracted with hexane and methanol [83]. Lipopeptides (laxaphicins B and C) obtained from Anabaena laxa have been found to possess fungicidal properties against Saccharomyces cerevisiae, Penicillium notatum, Aspergillus oryzae, Trichophyton mentagrophytes, and C. albicans [84]. ...
Microalgae and cyanobacteria (blue-green algae) are used as food by humans. They have gained a lot of attention in recent years because of their potential applications in biotechnology. Microalgae and cyanobacteria are good sources of many valuable compounds, including important biologically active compounds with antiviral, antibacterial, antifungal, and anticancer activities. Under optimal growth condition and stress factors, algal biomass produce varieties of potential bioactive compounds. In the current review, bioactive compounds production and their remarkable applications such as pharmaceutical and nutraceutical applications along with processes involved in identification and characterization of the novel bioactive compounds are discussed. Comprehensive knowledge about the exploration, extraction, screening, and trading of bioactive products from microalgae and cyanobacteria and their pharmaceutical and other applications will open up new avenues for drug discovery and bioprospecting.
... Fischerella sp. methanolic extract was active against Enterobacter aerogenes, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi, and Staphylococcus aureus as well as multidrug-resistant Escherichia coli strains in in vitro assays (Asthana et al. 2006). Some antialgal compounds and its source are listed in Table 6.2. ...
Cyanobacteria the least explored microorganisms have lots of potential for synthesis and production of numerous antimicrobial secondary metabolites. As they are ubiquitous in distribution and present in all possible habitats, cyanobacteria have developed several mechanisms to survive in various extreme habitats. Also, they are compatible biocatalysts, and they can be used in the field of “white biotechnology” for increasing the sustainable manufacture of nutraceutical and pharmaceutical compounds as novel drugs and also as clean energy sources such as biodiesel and hydrogen. Cyanobacteria are known as a mother of wide categories of secondary metabolites with different biological activities, i.e., antibacterial, antitumoral, antiviral, antifungal, antialgal, antimalarial, anti-inflammatory, and anticancer properties. In this chapter, we try to uncover the application of various metabolites like phytols, free fatty acids, exopolysaccharides, phenolics, terpenoids, phytoene, sterols, carotenoids, MAAs, scytonemin, phytohormones, cyanotoxins, biocides (algicides, fungicides, bactericides, and insecticides), etc. and its various applications.
... Fatty acids extracted from Fischerella sp. [53], Chlorella marina, Nannochloropsis oculata, and Chaetoceros affinis [54], and Schizochytrium sp. [55] have been evaluated in the treatment of wounds in animal models. ...
The search for natural products with benefits for skin regeneration has gained a much broader interest worldwide. Microalgae represent a natural source of interesting bioactive compounds with an impact on wound-healing applications. The potential beneficial effects of microalgal carotenoids, polyunsaturated fatty acids, polysaccharides, and crude extracts have been reported in wound-healing applications due to their different biological activities, namely: i) the quenching of reactive oxygen species; ii) the suppression of the production of inflammatory cytokines and transduction cascades, and iii) the prevention of the microbial growth at the wound site. Wound dressings based on microalgae, and their bioactive compounds, which are aimed at being used in the treatment of skin injuries, are reviewed. Finally, the emerging strategies in the production of live microalgae-based photosynthetic scaffolds for skin regeneration are also outlined.
... Furthermore, Asthana and coworkers investigated the potential of a Fischerella strain to produce the bioactive ɣ-linolenic acid under liquid culture conditions [96]. Lipids were not only found as antibacterial compounds but also as QS inhibitors. ...
Bacterial and viral infections pose a direct threat to human health due to the increase of drug-resistant and novel pathogenic strains. Natural products represent a prolific source of bioactive metabolites, which have been exploited for their therapeutic effects. In particular, cyanobacteria were identified as important producers of secondary metabolites possessing antibacterial and antiviral activities, among others. A meta-analysis indicated that some natural product classes target bacteria or viruses exclusively. This result also applied for some cyanobacterial species that were identified to produce only antibacterial or antiviral compounds. Furthermore, cyanobacteria represent a promising host for bio-production due to their ability to perform photosynthesis and their low-cost production requirements. This review highlights antibacterial and antiviral compounds isol isolated from cyanobacteria and the biotechnological application of these organisms .
... Marine organisms are a very important source of antimicrobial agents (Richards et al., 2001;Schillaci et al., 2010;Schillaci et al., 2013;Spinello et al., 2018;Vazzana et al., 2018;Núñez Acuña et al., 2018) and, among them, the PUFAs are normally present at high levels in Salmo salar (Linder, Fanni & Parmentier, 2005;Morais et al., 2009). Different studies have shown the antimicrobial activity of the salmon PUFAs against Gram-positive bacteria due to their specific components such as eicosapentaenoic acid (Desbois, Mearns-Spragg & Smith, 2009;Desbois & Lawlor, 2013), docosahexaenoic acid (Coonrod, 1987;Feldlaufer et al., 1993;Gladyshev et al., 2009), γ-linolenic acid (Asthana et al., 2006) and dihomoγ-linolenic acid (Feldlaufer et al., 1993). ...
Background and aims
Fish by-products are generally used to produce fishmeal or fertilizers, with fish oil as a by-product. Despite their importance, fish wastes are still poorly explored and characterized and more studies are needed to reveal their potentiality. The goal of the present study was to qualitatively characterize and investigate the antimicrobial effects of the fish oil extracted from Salmo salar waste samples and to evaluate the potential use of these compounds for treating pathogen infections.
Methods
Salmo salar waste samples were divided in two groups: heads and soft tissues. Fatty acids composition, and in particular the content in saturated (SAFAs), mono-unsaturated (MUFAs) and Polyunsaturated (PUFAs) fatty acids, was characterized through GC/MS Thermo Focus GC-DSQ II equipped with a ZB-5 fused silica capillary tubes column. The antimicrobial activity of the salmon waste oils was evaluated through the Minimum Inhibitory Concentration assay and the antibiotics contamination was determined by Liquid Chromatography with tandem Mass Spectrometry (LC-MS/MS) analysis. All experiments were done at least in triplicate.
Results
GC/MS analysis has shown the specific fatty acid composition of the salmon waste oils and their enrichment in MUFAs and PUFAs, with special reference to omega-3, -6, -7, -9 fatty acids. Furthermore, our study has highlighted the antimicrobial activity of the fish waste oil samples against two Gram+ and Gram- bacterial strains.
Conclusions
These data confirm that the fish waste is still quantitatively and qualitatively an important source of available biological properties that could be extracted and utilized representing an important strategy to counteract infective diseases in the context of the circular economy.
... Lipidic fractions, such as triglycerides and DPA, from C. muelleri showed activity against C. albicans, reported by Mendiola et al. (2007). Laxaphicins B and C are lipopeptides derived from Anabaena laxa and showed fungicidal properties against Saccharomyces cerevisiae, Penicillium notatum, Aspergillus oryzae, Trichophyton mentagrophytes, and C. albicans (Asthana et al., 2006). Fisherellin from Fischerella muscicola showed antialgal and antifungal properties (Dahms et al., 2006). ...
... MCs were already described to pose antimicrobial activity in non-resistant microbes and induce apoptosis in human cancer cell lines [73,74]. Compounds related with higher bioactivity in literature, however, represent more complex chemical classes [75][76][77], as well as compounds that are not yet characterized [78][79][80]. Our findings suggest that the compounds responsible for the bioactivity presented by the non-toxic TAU-MAC strains are yet unknown or not identified. ...
Cyanobacteria are a diverse group of photosynthetic Gram-negative bacteria that produce an array of secondary compounds with selective bioactivity against a broad spectrum of organisms and cell lines. In this study, 29 strains isolated from freshwaters in Greece were classified using a polyphasic approach and assigned to Chroococcales, Synechococcales, and Nostocales, representing 11 genera and 17 taxa. There were good agreements between 16S ribosomal RNA (rRNA)–cpcBA–internal genetic spacer (IGS) characterization and morphological features, except for the Jaaginema–Limnothrix group which appears intermixed and needs further elucidation. Methanol extracts of the strains were analyzed for cyanotoxin production and tested against pathogenic bacteria species and several cancer cell lines. We report for the first time a Nostoc oryzae strain isolated from rice fields capable of producing microcystins (MCs) and a Chlorogloeopsis fritschii strain isolated from the plankton of a lake, suggesting that this species may also occur in freshwater temperate habitats. Strains with very high or identical 16S rRNA gene sequences displayed different antibacterial and cytotoxic activities. Extracts from Synechococcus cf. nidulans showed the most potent antibacterial activity against Staphylococcus aureus, whereas Jaaginema sp. strains exhibited potent cytotoxic activities against human colorectal adenocarcinoma and hepatocellular carcinoma cells. Jaaginema Thessaloniki Aristotle University Microalgae and Cyanobacteria (TAU-MAC) 0110 and 0210 strains caused pronounced changes in the actin network and triggered the formation of numerous lipid droplets in hepatocellular carcinoma and green monkey kidney cells, suggesting oxidative stress and/or mitochondrial damage leading to apoptosis.
... Moreover, the promising antibacterial activity of the acidic fraction relative to other fractions could be contributed by the action of its major volatile component, linolenic acid (Table 1, [54]). It has been demonstrated that long-chain unsaturated fatty acids including linolenic acid exerted highly potent activity against gram-positive bacteria [61][62][63][64]. ...
Background:
Streblus asper is a well-known plant native to Southeast Asia. Different parts of the plant have been traditionally used for various medicinal purposes. However, there is very little scientific evidence reporting its therapeutic benefits for potential treatment of Alzheimer's disease (AD). The study aimed to evaluate antibacterial, antioxidant, acetylcholinesterase (AChE) inhibition, and neuroprotective properties of S. asper leaf extracts with the primary objective of enhancing therapeutic applications and facilitating activity-guided isolation of the active chemical constituents.
Methods:
The leaves of S. asper were extracted in ethanol and subsequently fractionated into neutral, acid and base fractions. The phytochemical constituents of each fraction were analyzed using GC-MS. The antibacterial activity was evaluated using a broth microdilution method. The antioxidant activity was determined using DPPH and ABTS radical scavenging assays. The neuroprotective activity against glutamate-induced toxicity was tested on hippocampal neuronal HT22 cell line by evaluating the cell viability using MTT assay. The AChE inhibitory activity was screened by thin-layer chromatography (TLC) bioautographic method.
Results:
The partition of the S. asper ethanolic leaf extract yielded the highest mass of phytochemical constitutions in the neutral fraction and the lowest in the basic fraction. Amongst the three fractions, the acidic fraction showed the strongest antibacterial activity against gram-positive bacteria. The antioxidant activities of three fractions were found in the order of acidic > basic > neutral, whereas the decreasing order of neuroprotective activity was neutral > basic > acidic. TLC bioautography revealed one component in the neutral fraction exhibited anti-AChE activity. While in the acid fraction, two components showed inhibitory activity against AChE. GC-MS analysis of three fractions showed the presence of major phytochemical constituents including terpenoids, steroids, phenolics, fatty acids, and lipidic plant hormone.
Conclusions:
Our findings have demonstrated the therapeutic potential of three fractions extracted from S. asper leaves as a promising natural source for neuroprotective agents with additional actions of antibacterials and antioxidants, along with AChE inhibitors that will benefit in the development of new natural compounds in therapies against AD.
... One of the promising cyanobacterial genus is Fischerella sp. antibacterial compounds including indole alkaloids ambiguines (Mo et al., 2009), and fischerindoles (Park et al., 1992), parsiguine (Gashemi et al., 2004), y-linolenic acid (Asthana et al., 2006) have been isolated from terrestrial freshwater and marine strains of this cyanobacterium. Ambiguine-K and -M isonitriles showed antibacterial activity against hard-to-treat Mycobacterium tuberculosis with MIC values of 6.6 and 7.5 μM, respectively (Shunyan et al., 2009). ...
Microalgal species commonly used and processed for use in foods and cosmetics
include Arthrospira (traditional name, Spirulina), Chlorella spp., Dunaliella spp.,
and Haematococcus spp. (Buono et al., 2014). The largest collection of microalgae
is the Collection of Freshwater Algae at the University of Coimbra, Portugal, where
over 4000 strains and 1000 species of algae are maintained. Several other countries
including Germany (the Culture Collection of Algae of the Gottingen University,
Germany), the United States (the Culture Collection of Algae in the University of
Texas), and Australia (the Australian National Algae Culture Collection) maintain
microalgae strains. Screening of algae is often based on optimal growth or the production
of specific metabolites (Larkum et al., 2012).
Functional foods or nutraceuticals may be defined in relation to microalgae as algal
extracts/powders used for human nutritional supplementation to impart a health benefit
to the consumer that goes above and beyond basic human nutrition. Microalgae are
nutritious and rich in essential amino acids, γ-linolenic acid (GLA), fibers,
B vitamins, calcium, phosphorous, iron, pigments such as β-carotene, xanthophylls,
chlorophyll, and other bioactive compounds. Studies have indicated that microalgae
have antiviral, antitumor, antioxidant, antiinflammatory, antiallergenic, antidiabetic,
and antibacterial properties as well as lipid-lowering effects (de Jesus Raposo et al.,
2013; Ku et al., 2013). Several microalgal compounds are currently used as
nutraceuticals/nutritional supplements. Beta-carotene production from Dunaliella in
open raceway ponds is due to the organism’s ability to withstand extremely high saline
conditions that limit competition. Beta-carotene from Dunaliella is currently valued at
US $ 1500 per kilogram, and its use as a nontoxic vitamin A precursor has made it a
mainstay in multivitamin and specialty formulations (Gellenbeck, 2012).
... Several fatty acids with anti-bacterial activity were isolated from microalgae (see table X). γ-linolenic acid from Fischerella sp. colonizing Neem tree bark showed minimum inhibitory concentrations (MIC) of 4 µg/mL against Staphylococcus aureus, 8 µg/mL against Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa and 16 µg/mL against Enterobacter aerogenes (Asthana et al., 2006). The γ-linolenic acid, together with coriolic and α-dimorphecolic acid seemed to be responsible for the anti-bacterial activity against Staphylococcus aureus of the crude n-hexane extract from microalgae Oscillatoria redekei with MIC of 75 µg/ml in the case of coriolic acid and 100 µg/mL for the remaining fatty acids (Mundt et al., 2003). ...
This chapter introduces the pharmaceutical applications of microalgae with respect to their potential properties. It overviews the previous and recent studies on antioxidant, antiinflammatory, antitumor, anticancer, antimicrobial, antiviral and antiallergic activities of microalgal bioactive molecules. It explains the potential mechanism underlying the effects of these molecules with the related pathways. By the end of the chapter the future prospects on the red biotechnology, including the developments in research and industry are explained. A full discussion of recent examples is included to raise the possibility of microalgal resources to become a promising compound in various types of industrial areas with the key concept of potential usage.
... In particular, the Subsection V cyanobacteria are well known for the production of the hapalindole-family of compounds, a group of structurally related indole alkaloids consisting of hapalindoles, welwitindolinones and fisherindoles which display a broad range of bioactivities [5, 6]. Other metabolites isolated from Subsection V cyanobacteria include the hepatotoxin microcystin789 , the cyclic peptide, hap- alosin [10, 11], hydrocarbons [12], fischerellin A and B131415, the cyclic peptide westiellamide [16] , the aromatic compounds ambigol A, B, C and 2,4-dichloro- benzoic acid [17, 18], the alkaloid tjipanazole D [18], the depsipeptide stigonemapeptin [19], the hexapeptide hapalocyclamide [20] , the antimicrobial compound par- siguine [21], and the long chain polyunsaturated fatty acid γ-Linolenic acid [22]. The majority of cyanobacterial natural products are non-ribosomal peptides, polyketides or hybrid peptidepolyketide compounds23242526. ...
Background: Cyanobacteria are well known for the production of a range of secondary metabolites. Whilst recent genome sequencing projects has led to an increase in the number of publically available cyanobacterial genomes, the secondary metabolite potential of many of these organisms remains elusive. Our study focused on the 11 publically available Subsection V cyanobacterial genomes, together with the draft genomes of Westiella intricata UH strain HT-29-1 and Hapalosiphon welwitschii UH strain IC-52-3, for their genetic potential to produce secondary metabolites. The Subsection V cyanobacterial genomes analysed in this study are reported to producea diverse range of natural products, including the hapalindole-family of compounds, microcystin, hapalosin, mycosporine-like amino acids and hydrocarbons.
Results: A putative gene cluster for the cyclic depsipeptide hapalosin, known to reverse P-glycoprotein multiple drug resistance, was identified within three Subsection V cyanobacterial genomes, including the producing cyanobacterium H. welwitschii UH strain IC-52-3. A number of orphan NRPS/PKS gene clusters and ribosomally-synthesised and post translationally-modified peptide gene clusters (including cyanobactin, microviridin and bacteriocin gene clusters) were identified. Furthermore, gene clusters encoding the biosynthesis of mycosporine-like amino acids, scytonemin, hydrocarbons and terpenes were also identified and compared.
Conclusions: Genome mining has revealed the diversity, abundance and complex nature of the secondary metabolite potential of the Subsection V cyanobacteria. This bioinformatic study has identified novel biosynthetic enzymes which have not been associated with gene clusters of known classes of natural products, suggesting that these cyanobacteria potentially produce structurally novel secondary metabolites.
... In particular, the Subsection V cyanobacteria are well known for the production of the hapalindole-family of compounds, a group of structurally related indole alkaloids consisting of hapalindoles, welwitindolinones and fisherindoles which display a broad range of bioactivities [5,6]. Other metabolites isolated from Subsection V cyanobacteria include the hepatotoxin microcystin [7][8][9], the cyclic peptide, hapalosin [10,11], hydrocarbons [12], fischerellin A and B [13][14][15], the cyclic peptide westiellamide [16], the aromatic compounds ambigol A, B, C and 2,4-dichlorobenzoic acid [17,18], the alkaloid tjipanazole D [18], the depsipeptide stigonemapeptin [19], the hexapeptide hapalocyclamide [20], the antimicrobial compound parsiguine [21], and the long chain polyunsaturated fatty acid γ-Linolenic acid [22]. ...
Cyanobacteria are well known for the production of a range of secondary metabolites. Whilst recent genome sequencing projects has led to an increase in the number of publically available cyanobacterial genomes, the secondary metabolite potential of many of these organisms remains elusive. Our study focused on the 11 publically available Subsection V cyanobacterial genomes, together with the draft genomes of Westiella intricata UH strain HT-29-1 and Hapalosiphon welwitschii UH strain IC-52-3, for their genetic potential to produce secondary metabolites. The Subsection V cyanobacterial genomes analysed in this study are reported to produce a diverse range of natural products, including the hapalindole-family of compounds, microcystin, hapalosin, mycosporine-like amino acids and hydrocarbons.
A putative gene cluster for the cyclic depsipeptide hapalosin, known to reverse P-glycoprotein multiple drug resistance, was identified within three Subsection V cyanobacterial genomes, including the producing cyanobacterium H. welwitschii UH strain IC-52-3. A number of orphan NRPS/PKS gene clusters and ribosomally-synthesised and post translationally-modified peptide gene clusters (including cyanobactin, microviridin and bacteriocin gene clusters) were identified. Furthermore, gene clusters encoding the biosynthesis of mycosporine-like amino acids, scytonemin, hydrocarbons and terpenes were also identified and compared.
Genome mining has revealed the diversity, abundance and complex nature of the secondary metabolite potential of the Subsection V cyanobacteria. This bioinformatic study has identified novel biosynthetic enzymes which have not been associated with gene clusters of known classes of natural products, suggesting that these cyanobacteria potentially produce structurally novel secondary metabolites.
... Although many tests have been performed, and strong antimicrobial activities were revealed in numerous cyanobacterial strains, few structures responsible for these activities have been identified. The compounds have mainly been classified to alkaloids, fatty acids, peptides, lipopeptides and terpenoids (Asthana et al., 2006;Silva-Stenico et al., 2010;Chlipala et al. 2011;Guedes et al., 2011;Nagarajan et al., 2012). In our studies, more than half of the pathogenic strains were sensitive to the extracts from the Baltic cyanobacteria. ...
... Although many tests have been performed, and strong antimicrobial activities were revealed in numerous cyanobacterial strains, few structures responsible for these activities have been identified. The compounds have mainly been classified to alkaloids, fatty acids, peptides, lipopeptides and terpenoids (Asthana et al., 2006;Silva-Stenico et al., 2010;Chlipala et al. 2011;Guedes et al., 2011;Nagarajan et al., 2012). In our studies, more than half of the pathogenic strains were sensitive to the extracts from the Baltic cyanobacteria. ...
Cyanobacteria are effective producers of bioactive metabolites, including both acute toxins and potential pharmaceuticals. In the current work, the biological activity of 27 strains of Baltic cyanobacteria representing different taxonomic groups and chemotypes were tested in a wide variety of assays. The cyanobacteria showed strain-specific differences in the induced effects. The extracts from Nodularia spumigena CCNP1401 were active in the highest number of tests, including protease and phosphatase inhibition assays. Four strains from Nostocales and four from Oscillatoriales increased proliferation of mitogen-stimulated human T cells. In antimicrobial assays, Phormidium sp. CCNP1317 (Oscillatoriales) strongly inhibited the growth of six fouling Gammaproteobacteria. The growth of monocotyl Sorghum saccharatum was inhibited by both toxin-producing and ‘non-toxic’ strains. The Baltic cyanobacteria were also found to be a rich source of commercially important enzymes. Among the 19 enzymatic activities tested, alkaline phosphatase, acid phosphatase, esterase (C4 and C8), and naphthol-AS-BI-phosphohydrolase were particularly common. In the cyanobacterial extracts, different peptides which may have been responsible for the observed effects were identified using LC-MS/MS. Their structures were classified to microcystins, nodularins, anabaenopeptins, cyanopeptolins, aeruginosins, spumigins and nostocyclopeptides.
... Gamma-linolenic acid from Fischerella sp. inhibited S. aureus (ATCC 25923) (MIC 4 lg/ml) (Asthana et al. 2006), whilst ambiguine I isonitrile, extracted from Fischerella sp. (TAU IL-199-3-1), inhibited B. subtilis (MIC 0.312 lg/ml) and Staphylococcus albus Welch (as Staphylococcus epidermidis) (MIC 0.078 lg/ ml) (Raveh & Carmeli 2007). ...
Bacterial resistance to antibiotics is an issue receiving significant attention and highlights the urgent need for new classes of antibiotics. This has led to exploration for natural compounds from relatively unexplored microorganisms including microalgae. These photosynthetic organisms are extremely diverse and ubiquitous and have been shown to produce compounds that exhibit antibacterial activity against human pathogens. Their ability to survive in a wide range of environmental conditions and the possibility of culture condition manipulation for optimization of antibacterial compounds suggests that they have significant potential. However, only a few species have been so far investigated, and very few metabolites characterized. This review provides an overview of this research and illustrates the opportunity for significantly more systematic investigation of these microorganisms.
... EPS produced by Nostoc sphaeroides, Spirulina platensis, Aphanizomenon flos-aquae, and Chlorella pyrenoidosa has recently been reported to have a significant antitumor activity (Li et al. 2011;Pugh et al. 2001). Notably, no report was found concerning the toxicity of the cyanobacterial fatty acids to cancer cells, although in a large number of studies it has been shown that they are responsible for a broad spectrum of antibacterial (Asthana et al. 2006;Mundt et al. 2003) and allelopathic activities (Ikawa 2004). ...
The cytotoxic, antibacterial, and antifungal activities
of cyanobacterium Gloeocapsa sp. strain Gacheva
2007/R-06/1 were investigated and the possibility for an
enhancement of these activities by changing the culture
conditions evaluated. Fatty acids of this cyanobacterium
were found to be active against Streptococcus pyogenes.
Exopolysaccharides inhibited the growth of both Grampositive
and Gram-negative bacteria and the fungus Candida
albicans. Both exopolysaccharides and fatty acid mixtures
also significantly decreased the viability of human
cervical carcinoma cells, HeLa. Greater biological activities
were exhibited by Gloeocapsa sp., cultured at suboptimal
temperatures (15–26°C) than at optimal and supraoptimal
ones. In comparison with higher light intensity, the low-light
cultivation stimulated the cytotoxicity of the fatty acids. In
general, low temperatures decreased the growth of Gloeocapsa
sp., but promoted its biological activity. Prolonged cultivation
also had a beneficial impact on the bioactivity.
Compared to 4 days, the 17-day cultivation resulted in
fourfold higher antibacterial and antifungal activities of
exopolysaccharides and more than twice increases in their
cytotoxicity. The study revealed that this cyanobacterial
isolate is a new source of natural products with potential
for pharmacological and medical applications.
... Asthana et al. [157] reported that the methanolic extract of Fischerella spp. was active against Mycobacterium tuberculosis, Enterobacter aerogens, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi, E. coli as well as 3 multi drug resistant E. coli strains in in-vitro assays. They also found that the active principle was Hapalindole T, based on MS, UV, IR and H-NMR analyses, with a molecular weight of 386 and a melting point range of 179-182 °C. ...
Cyanobacteria (blue-green algae) are Gram-negative oxygenic photosynthetic prokaryotes with a long evolutionary history. They have potential applications in diverse areas, especially in agriculture, as nutrient supplements in agriculture and industry (as biofertilizer, plant growth promoting rhizobacteria and as biocontrol agents). Their role as food supplements/nutraceuticals and in bioremediation and wastewater treatment is an emerging area of interest. In addition, they are known to produce wide array of bioactive compounds (secondary metabolites) with diverse biological activities — including antiviral, antibacterial, antifungal, antimalarial, antitumoral and anti-inflammatory properties, having therapeutic, industrial and agricultural significance. One of the major problems has been regarding their classification being incongruent with the phylogeny, because the phenotype of cyanobacterial strains is known to be altered under different environmental/nutritional conditions. However, because of their simple growth needs, they are the favourite model organisms for deeper understanding of several metabolic processes and for the production of recombinant compounds of medicinal and commercial value. In recent years, cyanobacteria have gained interest for producing third generation biofuels (both biomass and H2 production). With the recent advances in metabolic engineering techniques and availability of genome sequences, novel approaches are being explored for realising the potential of cyanobacteria. Our review provides an overview of the polyphasic approaches used in the analyses of cyanobacterial biodiversity and the potential of these organisms in providing viable solutions to global problems of food, energy and environmental degradation, which need further impetus through adoption of multidisciplinary collaborative programs.
... EPS produced by Nostoc sphaeroides, Spirulina platensis, Aphanizomenon flos-aquae, and Chlorella pyrenoidosa has recently been reported to have a significant antitumor activity (Li et al. 2011;Pugh et al. 2001). Notably, no report was found concerning the toxicity of the cyanobacterial fatty acids to cancer cells, although in a large number of studies it has been shown that they are responsible for a broad spectrum of antibacterial (Asthana et al. 2006;Mundt et al. 2003) and allelopathic activities (Ikawa 2004). ...
The cytotoxic, antibacterial, and antifungal activities of cyanobacterium Gloeocapsa sp. strain Gacheva 2007/R-06/1 were investigated and the possibility for an enhancement of these activities by changing the culture conditions evaluated. Fatty acids of this cyanobacterium were found to be active against Streptococcus pyogenes. Exopolysaccharides inhibited the growth of both Gram-positive and Gram-negative bacteria and the fungus Candida albicans. Both exopolysaccharides and fatty acid mixtures also significantly decreased the viability of human cervical carcinoma cells, HeLa. Greater biological activities were exhibited by Gloeocapsa sp., cultured at suboptimal temperatures (15–26°C) than at optimal and supraoptimal ones. In comparison with higher light intensity, the low-light cultivation stimulated the cytotoxicity of the fatty acids. In general, low temperatures decreased the growth of Gloeocapsa sp., but promoted its biological activity. Prolonged cultivation also had a beneficial impact on the bioactivity. Compared to 4 days, the 17-day cultivation resulted in fourfold higher antibacterial and antifungal activities of exopolysaccharides and more than twice increases in their cytotoxicity. The study revealed that this cyanobacterial isolate is a new source of natural products with potential for pharmacological and medical applications.
... EPS produced by Nostoc sphaeroides, Spirulina platensis, Aphanizomenon flos-aquae, and Chlorella pyrenoidosa has recently been reported to have a significant antitumor activity (Li et al. 2011;Pugh et al. 2001). Notably, no report was found concerning the toxicity of the cyanobacterial fatty acids to cancer cells, although in a large number of studies it has been shown that they are responsible for a broad spectrum of antibacterial (Asthana et al. 2006;Mundt et al. 2003) and allelopathic activities (Ikawa 2004). ...
... The antibacterial activities of microalgae have been attributed -at least in part, to unsaturated fatty acids of chain lengths above ten carbon atoms (Naviner et al., 1999;Asthana et al., 2006Asthana et al., , 2009. For instance, eicosapentaenoic acid (EPA) from Phaeodactylum tricornutum was claimed to possess antibacterial activity against both Gram-positive and -negative bacteria, including multiple-resistant Staphylococcus aureus (Benkendorff et al., 2005). ...
Intra-and extracellular extracts of thirteen cyanobacteria and twelve microalgae were screened for their activity against a few of the most relevant food-borne pathogens – viz. Salmonella sp., Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. Strain M2-1 of Scenedesmus obliquus was the microalga that exhibited the highest antibacterial activity, except against Salmonella sp. Although cyanobacteria possessed in general wider antibacterial spectra than microalgae, the former have also been associated with toxin production – and may thus be less useful in food formulation. Nostoc sp. was particularly effective against E. coli and P. aeruginosa, whereas Gloeothece sp. stood out because of its capacity to inhibit all food pathogens tested. Typically, the intracellular extracts were more powerful than their extracellular counterparts; and those with antibacterial features were found to possess high contents of long chain fatty acids – some of which are well-known for their antibacterial activities.
... As cyanobacteria are the early microorganisms on the earth which contribute to altering the atmosphere, they have several adaptative mechanisms to survive in extreme or variable environments [25]. The nutrient medium can affect the growth, metabolism [14], phycobiliproteins [11] or even antimicrobial properties [1]. Studies of Iranian rice fields have revealed not only favorable conditions for biological nitrogen fixation but also development of this cyanobacterium [5, 23 and 24]. ...
In the present research the growth and metabolism of cyanobacterium Fischerella sp. FS18, isolated from rice fields of Gillan Province (Iran), were evaluated in different nitrogen sources. This strain is a good candidate as biological fertilizer due to high efficiency to N 2 fixation. In this way, cells in logarithmic phase of stock were treated with different nitrogen sources (N-free, 1 & 2 mM NH 4 + and 5 and 10 mM NO 3 −). Results indicated that maximum growth rate belonged to NO 3 − treatment. Dry weights of Fischerella sp. FS18 in N-free medium and ammonium were in decreasing order of preference; and NH 4 + 2 mM was drastically toxic for this strain. The highest chlorophyll concentration was detected in N-free medium. NO 3 − 5 mM and NH 4 + 2 mM had the lower contents of this pigment. Photosynthesis rate varied the same as chlorophyll. phycocyanin and phycoerythrin had the highest rate in nitrate. The highest light-saturated photosynthetic rate and also steepest initial slope clearly belonged to nitrogen free-medium. All types of combined nitrogen sources had inhibitory effect on nitrogenase activity, regardless of the concentrations used. Our results indicated that Fischerella sp. FS18 is a potent diazotrophic species with increasing growth in the presence of nitrate; and ammonium 2mM seems to be toxic for it.
... Therefore, the search for new antimicrobial natural products continues to draw attention for many researchers . Chinese medicinal herbs have been used for a long time and undoubtedly a valuable resource for new antibacterial agents (Tsai et al., 2008; Asthana et al., 2006; Natarajan et al., 2008). Chinese medicines account for a source of many natural ingredients to be developed as new antimicrobial drugs in spite of the fact that their antibacterial and antifungal action has been proven to be remarkably milder than that of commercial synthetic drugs (Tian et al., 2009; Shan et al., 2008). ...
Recently, multiple resistances in human pathogenic microorganisms have developed and caused serious nosocomial infections, especially Acinetobacter baumannii. In this study, we aim to look for new antimicrobial substances against drug resistance strains from Chinese herbal medicines. By using the disc diffusion method, 58 ethanol extracts of Chinese herbal medicines were screened for the antimicrobial activity against 78 clinical A. baumannii isolates. Among the 58 plant extracts, the extracts of Picarpium trichosanthis showed substantial higher broad antibacterial spectrum against the entire test organisms. The ethyl acetate (EA) fraction obtained from partition extraction revealed the antibacterial activity with MIC value at 1.9 mg/ml. The EA fraction of P. trichosanthis could be a bactericide based on the killing curve. The chemical components of the extracts were analyzed by GC-MS; 4-hydroxybenzoic and isovanillic acid were evidenced to provide the antibacterial and antioxidant activity, respectively. Moreover, the results obtained from SEM observation showed that the active extract might inhibit the function of outer membrane of the organisms. Overall, the extracts of P. trichosanthis present antibacterial and antioxidant activity indeed have the valuable to be developed into the antibiotic medicines.
... Fatty acids such as a-dimorphecolic (38), coriolic (39), and linoleic (40) acids from Oscillatoria redekei were capable of inhibiting the growth of the Grampositive bacteria B. subtilis, Micrococcus flavus and Staphylococcus aureus, although their activities were moderate with MIC values of 75-100 lg/ml (Mundt et al. 2003). A more active fatty acid was c-linolenic acid (41), produced by Fischerella sp., which also demostrated growth inhibition of Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa, Salmonella typhi and S. aureus with MIC values of 4-16 lg/ml (Asthana et al. 2006). More non polar antimicrobial compounds were propanoic (42) and butanoic acids (43) as major components of an active mixture (MIC = 3-16 mg/ml) against Aspergillus niger, C. albicans, E. coli, and S. aureus, this was obtained from Haematococcus pluvialis (Rodríguez-Meizoso et al. 2010). ...
Microorganisms are recognized worldwide as the major source of secondary metabolites with mega diverse structures and promissory
biological activities. However, as yet many of them remain little or under-explored like the microbiota from freshwater aquatic
ecosystems. In the present review, we undertook a recompilation of metabolites reported with pesticidal properties from microalgae
(cyanobacteria and green algae) and fungi, specifically from freshwater aquatic habitats.
KeywordsBioactive metabolites–Cyanobacteria–Freshwater ecosystems–Fungi–Microalgae
The development of multiple-drug-resistant pathogens has prompted medical research toward the development of new and effective antimicrobial therapies. Much research into novel antibiotics has focused on bacterial and fungal compounds, and on chemical modification of existing compounds to increase their efficacy or reactivate their antimicrobial properties. In contrast, cyanobac-teria have been relatively overlooked for antibiotic discovery, and much more work is required. This may be because some cyanobacterial species produce environmental toxins, leading to concerns about the safety of cyanobacterial compounds in therapy. Despite this, several cyanobacterial-derived compounds have been identified with noteworthy inhibitory activity against bacterial, fungal and protozoal growth, as well as viral replication. Additionally, many of these compounds have relatively low toxicity and are therefore relevant targets for drug development. Of particular note, several linear and heterocyclic peptides and depsipeptides with potent activity and good safety indexes have been identified and are undergoing development as antimicrobial chemotherapies. However, substantial further studies are required to identify and screen the myriad other cyanobacterial-derived compounds to evaluate their therapeutic potential. This study reviews the known phytochemistry of cyanobacteria, and where relevant, the effects of those compounds against bacterial, fungal, protozoal and viral pathogens, with the aim of highlighting gaps in the literature and focusing future studies in this field.
Cyanobacteria are a ubiquitous and ecologically important group of microorganisms; they are prokaryotic oxygenic phototrophs belonging to the kingdom Monera and division Cyanophyta. An estimated 150 genera contain approximately 2000 species of cyanobacteria. They have been largely responsible for oxygen production on earth, sustaining the oxygen levels for nearly 3.5 billion years. They resemble Gram-negative bacteria notwithstanding their photoautotrophic physiology and reproduce by vegetative and asexual processes; sexual reproduction is entirely absent. Their morphology ranges from unicellular, filamentous, or colonial and is visible by the naked eye during blooms. They are found in both terrestrial and aquatic habitats and can mutually exist with other organisms such as plants and animals; they are found in fresh to marine water, hot deserts to extreme cold conditions such as Antarctica and the Arctic that suggest that they can tolerate an enormous array of environmental conditions such as light intensities, pH, temperatures, and salinity. Furthermore, the metabolic adaptations to certain environmental conditions are associated with the diversity of the organisms and their metabolites.
In view of their broad color variation and superior antioxidant activity, carotenoids are widely used in the food, cosmetic, pharmaceutical, and feed industries. Cyanobacteria are well-known producers of commercially important carotenoids, such as β-carotene and zeaxanthin. Furthermore, metabolic engineering of cyanobacteria for the production of valuable carotenoids, such as astaxanthin and lutein, has garnered significant interest in recent years because it offers the advantages of simple cultivation, harvesting, and genetic manipulation. This chapter describes the potential of cyanobacteria as carotenoid producers, the applications of carotenoids, the biological activities exhibited by carotenoids (e.g., antioxidant, cardioprotective, and anticancer), and the recent progress in carotenoid processing technology (e.g., extraction, formulation, and isomerization).
Cyanobacteria (blue-green algae) are Gram-negative photosynthetic eubacteria that are found everywhere. This largest group of photosynthetic prokaryotes is rich in structurally novel and biologically active compounds; several of which have been utilized as prospective drugs against cancer and other ailments, as well. Consequently, the integument of nanoparticles-synthetic approaches in cyanobacterial extracts should increase pharmacological activity. Moreover, silver nanoparticles (AgNPs) are small materials with diameters below 100 nm that are classified into different classes based on their forms, sizes, and characteristics. Indeed, the biosynthesized AgNPs are generated with a variety of organisms, algae, plants, bacteria, and a few others, for the medicinal purposes, as the bioactive compounds of curio and some proteins from cyanobacteria have the potentiality in the treatment of a wide range of infectious diseases. The critical focus of this review is on the antimicrobial, antioxidant, and anticancer properties of cyanobacteria. This would be useful in the pharmaceutical industries in the future drug development cascades.
Communicated by Ramaswamy H. Sarma
Cyanobacteria (blue-green algae) are Gram-negative photosynthetic eubacteria that are found everywhere. This largest group of photosynthetic prokaryotes is rich in structurally novel and biologically active compounds; several of which have been utilized as prospective drugs against cancer and other ailments, as well. Consequently, the integument of nanoparticles-synthetic approaches in cyanobacterial extracts should increase pharmacological activity. Moreover, silver nanoparticles (AgNPs) are small materials with diameters below 100 nm that are classified into different classes based on their forms, sizes, and characteristics. Indeed, the biosynthesized AgNPs are generated with a variety of organisms, algae, plants, bacteria, and a few others, for the medicinal purposes, as the bioactive compounds of curio and some proteins from cyanobacteria have the potentiality in the treatment of a wide range of infectious diseases. The critical focus of this review is on the antimicrobial, antioxidant, and anticancer properties of cyanobacteria. This would be useful in the pharmaceutical industries in the future drug development cascades. Communicated by Ramaswamy H. Sarma
Increasing drug resistance in pathogenic microorganisms especially fungi and bacteria, menace caused by AIDS in modern society, spread of dreaded cancer disease worldwide, especially in third-world countries led the scientists to look at nature and little explored microalgae which seem to be a bioresource for biomolecules. Microalgae, in general, involve all microscopic algae including cyanobacteria which have originated on earth ̴2.8 billion years ago. Modern knowledge of genomics, proteomics and understanding of the strategy of survival of such microalgal strains inhabiting various environments including extreme habitats must be endowed with specific metabolic pathways, producing specific biomolecules of synthetic biochemist's interest. Bioassays of microalgal extracts clearly demonstrate their potential to kill fungi and bacteria and to inhibit growth of viral and cancer cells. The identification of target biomolecules is a difficult task. Modern instruments including chromatography and high-resolution mass spectrometry led to the isolation and identification of biomolecules. However, small quantities of biomolecules (μg/g dry weight) made it difficult to produce at large scale. This chapter reviews the state of the art in extraction, purification and extent of nanotechnology for its impact on microbial system as well as cancer cells. Constraints in commercialization of biomolecules and drug production and its overcoming strategies are also discussed.
Cyanobacteria and algae having complex photosynthetic systems can channelize absorbed solar energy into other forms of energy for production of food and metabolites. In addition, they are promising biocatalysts and can be used in the field of “white biotechnology” for enhancing the sustainable production of food, metabolites, and green energy sources such as biodiesel. In this review, an endeavor has been made to uncover the significance of various metabolites like phenolics, phytoene/terpenoids, phytols, sterols, free fatty acids, photoprotective compounds (MAAs, scytonemin, carotenoids, polysaccharides, halogenated compounds, etc.), phytohormones, cyanotoxins, biocides (algaecides, herbicides, and insecticides) etc. Apart from this, the importance of these metabolites as antibiotics, immunosuppressant, anticancer, antiviral, anti-inflammatory agent has also been discussed. Metabolites obtained from cyanobacteria and algae have several biotechnological, industrial, pharmaceutical, and cosmetic uses which have also been discussed in this review along with the emerging technology of their harvesting for enhancing the production of compounds like bioethanol, biofuel etc. at commercial level. In later sections, we have discussed genetically modified organisms and metabolite production from them. We have also briefly discussed the concept of bioprocessing highlighting the functioning of companies engaged in metabolites production as well as their cost effectiveness and challenges that are being addressed by these companies.
This chapter introduces the pharmaceutical applications of microalgae with respect to their potential properties. It overviews the previous and recent studies on antioxidant, antiinflammatory, antitumor, anticancer, antimicrobial, antiviral and antiallergic activities of microalgal bioactive molecules. It explains the potential mechanism underlying the effects of these molecules with the related pathways. By the end of the chapter the future prospects on the red biotechnology, including the developments in research and industry are explained. A full discussion of recent examples is included to raise the possibility of microalgal resources to become a promising compound in various types of industrial areas with the key concept of potential usage.
Soil microorganisms are known to play an active role in increased crop yields and soil fertility through a diverse array of mechanisms and such organisms are termed as PGPR (Plant Growth Promoting Rhizobacteria). This enhancement has been attributed to their involvement in the cycle of nutrients like carbon and nitrogen or in the decomposition of the organic matter, or production of allelopathic metabolites or enzymes influencing the pathogenic flora/fauna which indirectly promotes plant growth. Cyanobacteria are a ubiquitous group of organisms which have been relatively less investigated as PGPR, although their role in nitrogen dynamics of paddy based cropping systems is well investigated. Cyanobacteria are known to produce compounds with a wide range of activities, including phytohormones, biocidal metabolites or nutraceuticals. The interactions between agriculturally useful heterotrophic bacteria and autotrophs such as cyanobacteria can be effective and environment friendly options as biocontrol agents and biofertilizers. Plant-microbe partnerships are increasingly being focussed for not only nutrient management, but also for improving biomass production and remediation of polluted/inhospitable environments. This compilation provides an overview of the developments on this aspect and projections for the future.
Freshwater and terrestrial cyanobacteria resemble the marine forms in producing divergent chemicals such as linear, cyclic and azole containing peptides, alkaloids, cyclophanes, terpenes, lactones, etc. These metabolites have wider biomedical potentials in targeting proteases, cancers, parasites, pathogens and other cyanobacteria and algae (allelopathy). Among the various families of non-marine cyanobacterial peptides reported, many of them are acting as serine protease inhibitors. While the micropeptin family has a preference for chymotrypsin inhibition rather than other serine proteases, the aeruginosin family targets trypsin and thrombin. In addition, cyanobacterial compounds such as scytonemide A, lyngbyazothrins C and D and cylindrocyclophanes were found to inhibit 20S proteosome. Apart from proteases, metabolites blocking the other targets of cancer pathways may exhibit cytotoxic effect. Colon and rectum, breast, lung and prostate are the worst affecting cancers in humans and are deduced to be inhibited by both peptidic and non-peptidic compounds. Moreover, the growth of infections causing parasites such as Plasmodium, Leishmania and Trypanosoma are well controlled by peptides: aerucyclamides A-D, tychonamides and alkaloids: nostocarboline and calothrixins. Likewise, varieties of cyanobacterial compounds tend to inhibit serious infectious disease causing bacterial, fungal and viral agents. Interestingly, portoamides, spiroidesin, nostocyclamide and kasumigamide are the allelopathic peptides determined to suppress the growth of toxic cyanobacteria and nuisance algae. Thus cyanobacterial compounds have a broad bioactive spectrum; the analysis of SAR studies will not only assist to find out the mode of action but also reveal bioactive key components. Thereby, developing the drugs bearing these bioactive skeletons to treat various illnesses is wide open. Copyright © 2012 John Wiley & Sons, Ltd.
Allelopathic interactions involving cyanobacteria are being increasingly explored for the pharmaceutical and environmental significance of the bioactive molecules. Among the toxic compounds produced by cyanobacteria, the biosynthetic pathways, regulatory mechanisms, and genes involved are well understood, in relation to biotoxins, whereas the cytotoxins are less investigated. A range of laboratory methods have been developed to detect and identify biotoxins in water as well as the causal organisms; these methods vary greatly in their degree of sophistication and the information they provide. Direct molecular probes are also available to detect and (or) differentiate toxic and nontoxic species from environmental samples. This review collates the information available on the diverse types of toxic bioactive molecules produced by cyanobacteria and provides pointers for effective exploitation of these biologically and industrially significant prokaryotes.
The pharmaceutical interest and limited availability of gamma-linolenic acid (GLA) and eicosapentaenoic acid (EPA) prompted the search for genetic means for increasing the production of these fatty acids from algal sources. Cell lines of Spirulina platensis and Porphyridium cruentum resistant to the growth inhibition of the herbicide Sandoz 9785 were selected by serial transfers of the culture in the presence of increasing concentrations of the herbicide. The resistant cell lines of S. platensis overproduced GLA and those of P. cruentum overproduced EPA and were stable for at least 50 generations in the absence of the inhibitor.
Spirulina platensis was cultivated, in comparative studies, using several sources of nitrogen. The standard source used (sodium nitrate) was the same as that used in the synthetic medium Zarrouk, whereas the alternative nitrogen sources consisted of ammonium nitrate, urea, ammonium chloride, ammonium sulphate or acid ammonium phosphate. The initial nitrogen concentrations tested were 0.01, 0.03 and 0.05 M in an aerated photobioreactor at 30 C, with an illuminance of 1900 lux, and 12 h-light/12 h-dark photoperiod over a period of 672 h. Maximum biomass was produced in medium containing sodium nitrate (0.01–0.03–0.05 M), followed by ammonium nitrate (0.01 M) and urea (0.01 M). The final biomass concentrations were 1.992 g l–1 (0.03 M sodium nitrate), 1.628 g l–1 (0.05 M sodium nitrate), 1.559 g l–1 (0.01 M sodium nitrate), 0.993 g l–1 (0.01 M ammonium nitrate) and 0.910 g l–1 (0.01 M urea). This suggested that it is possible to utilize nitrogen sources other than sodium nitrate for growing S. platensis, in order to decrease the production costs of scaled up projects.
As a relatively prolific producer of GLA, the strain of Mucor sp LB-54 was selected for a study at different growth temperatures in shaker flask culture. The strain used in our experiment was capable to accumulate a relatively high amount of intracellular lipid, 20.73 % of dry cell weight, and GLA content of 15 % of total fatty acids after 5 days of incubation at 28°C. As the growth temperature was decreased from 28 to 12°C the percentage of GLA increased from 15 to 24 % of total fatty acids. In order to optimize the culture conditions for rapid biomass production and lipid production with a high proportion of GLA, the fungus was grown at two temperature combinations associated supplies of carbon source (glucose) in the culture medium. Maximal production of GLA (74 mg/l) was obtained from the Mucor sp LB-54 strain after 5 days of incubation at 28°C in basal medium following glucose addition (7 % w/v) and incubation for an additional 3 days at 12°C. The identity of GLA found in the strain of Mucor sp LB-54 was confirmed by the coupled gas chromatography-mass spectrometry
gamma-Linolenic acid (GLA; C18:3 delta(6,9,12)) is a component of the seed oils of evening primrose (Oenothera spp.), borage (Borago officinalis L.), and some other plants. It is widely used as a dietary supplement and for treatment of various medical conditions. GLA is synthesized by a delta6-fatty acid desaturase using linoleic acid (C18:2 delta(9,12)) as a substrate. To enable the production of GLA in conventional oilseeds, we have isolated a cDNA encoding the delta6-fatty acid desaturase from developing seeds of borage and confirmed its function by expression in transgenic tobacco plants. Analysis of leaf lipids from a transformed plant demonstrated the accumulation of GLA and octadecatetraenoic acid (C18:4 delta(6,9,12,15)) to levels of 13.2% and 9.6% of the total fatty acids, respectively. The borage delta6-fatty acid desaturase differs from other desaturase enzymes, characterized from higher plants previously, by the presence of an N-terminal domain related to cytochrome b5.
The nucleotide sequence of the entire genome of a filamentous cyanobacterium, Anabaena sp. strain PCC 7120, was determined. The genome of Anabaena consisted of a single chromosome (6,413,771 bp) and six plasmids, designated pCC7120alpha (408,101 bp), pCC7120beta (186,614 bp), pCC7120gamma (101,965 bp), pCC7120delta (55,414 bp), pCC7120epsilon (40,340 bp), and pCC7120zeta (5,584 bp). The chromosome bears 5368 potential protein-encoding genes, four sets of rRNA genes, 48 tRNA genes representing 42 tRNA species, and 4 genes for small structural RNAs. The predicted products of 45% of the potential protein-encoding genes showed sequence similarity to known and predicted proteins of known function, and 27% to translated products of hypothetical genes. The remaining 28% lacked significant similarity to genes for known and predicted proteins in the public DNA databases. More than 60 genes involved in various processes of heterocyst formation and nitrogen fixation were assigned to the chromosome based on their similarity to the reported genes. One hundred and ninety-five genes coding for components of two-component signal transduction systems, nearly 2.5 times as many as those in Synechocystis sp. PCC 6803, were identified on the chromosome. Only 37% of the Anabaena genes showed significant sequence similarity to those of Synechocystis, indicating a high degree of divergence of the gene information between the two cyanobacterial strains.
Changes in glycerolipid and fatty acid composition with a change in growth temperature were studied in the cyanobacterium, Synechocystis PCC6803. Under isothermal growth conditions, temperature did not significantly affect the composition of the various classes of lipids, but a decrease in temperature altered the degree of unsaturation of C(18) acids at the sn-1 position, but not that of C(16) acids at the sn-2 position of the glycerol moiety in each class of lipids. When the growth temperature was shifted from 38 degrees C to 22 degrees C, the desaturation of C(18) acids, but not that of C(16) acids, was stimulated. The desaturation of fatty acids occurred only in the light and was inhibited by chloramphenicol, rifampicin and 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, but not by cerulenin, an inhibitor for fatty acid synthesis. These findings suggest that desaturase activities are induced after a shift from a higher to a lower temperature, and that the desaturation of fatty acids is connected with the reactions involved in photosynthetic electron transport.
Lipid decomposition studies in frozen fish have led to the development of a simple and rapid method for the extraction and purification of lipids from biological materials. The entire procedure can be carried out in approximately 10 minutes; it is efficient, reproducible, and free from deleterious manipulations. The wet tissue is homogenized with a mixture of chloroform and methanol in such proportions that a miscible system is formed with the water in the tissue. Dilution with chloroform and water separates the homogenate into two layers, the chloroform layer containing all the lipids and the methanolic layer containing all the non-lipids. A purified lipid extract is obtained merely by isolating the chloroform layer. The method has been applied to fish muscle and may easily be adapted to use with other tissues.
The blue-green alga, Spirulina maxima, examined in the form of a spray-dried powder, contains 11% of lipid, which has been analysed in detail with a view to establishing both the classes of lipid present and their fatty acid profiles. The dominant lipids are mono-, di- and probably higher galactosyldiglycerides and phosphatidyl glycerol. Unlike other algae, Spirulina synthesises cis-6-cis-9-cis-12 octadecatrienoic acid in contrast to its 9–12–15 isomer.
The fatty acid distribution in 19 strains of Spirulina was studied. All but one contained γ-linolenic acid (GLA). No GLA was found in S. subsalsa, which had a very high content of palmitoleic acid. The fatty acid content of all but one of the tested strains increased with cultivation temperature and the relative amount of polyunsaturated fatty acid decreased. The highest content of GLA was found at 30–35° for most strains. High light intensities at a high temperature (38°), while not affecting the fatty acid composition, had a drastic effect on the fatty acid content, reducing it by as much as 46 %.
The enzyme 6-desaturase is responsible for the conversion of linoleic acid (18:2) to -linolenic acid (18:3). A cyanobacterial gene encoding 6-desaturase was cloned by expression of a Synechocystis genomic cosmid library in Anabaena, a cyanobacterium lacking 6-desaturase. Expression of the Synechocystis 6-desaturase gene in Anabaena resulted in the accumulation of -linolenic acid (GLA) and octadecatetraenoic acid (18:4). The predicted 359 amino acid sequence of the Synechocystis 6-desaturase shares limited, but significant, sequence similarity with two other reported desaturases. Analysis of three overlapping cosmids revealed a 12-desaturase gene linked to the 6-desaturase gene. Expression of Synechocystis 6-and 12-desaturase in Synechococcus, a cyanobacterium deficient in both desaturases, resulted in the production of linoleic acid and -linolenic acid.
Effect of culture conditions on cell growth, lipid accumulation and -linolenic acid production is reported for four Mortierella species. The highest concentration as well as the highest productivity of -linolenic acid in lipid was determined in strains of M. ramanniana. M. ramanniana CBS 112.08 was used in the studies of the influence of medium composition, concentration of carbon- and nitrogen sources and growth temperature. Several carbon sources provided good growth and a high lipid content in biomass. The highest dry weights (11–12g/l) and lipid contents (24%, w/w), were observed if glucose or fructose was used as carbon source, whereas the highest amount of -linolenic acid (26%) was determined in starch-grown cells. The fatty acid composition in the lipid was influenced by the cultivation time, growth temperature and, to a minor extent, by the carbon source used. In fermentor cultures, both strains of Mortierella ramanniana showed relatively poor growth and incomplete consumption of glucose. M. vinacea, on the other hand, grew well in tower reactors. M. vinacea, which has a different morphology than M. ramanniana strains, also showed higher yields of biomass and lipid and higher yield coefficients than the latter.
The oleaginous fungus Entomophthora exitalis was grown in continuous culture at a constant dilution rate (0.04 h–1) and over a range of temperatures (20–30 C). As the growth temperature was decreased from 30 to 20 C the percentage of polyunsaturated fatty acids (PUFA) increased proportionally from 18 to 27% (w/w) of the total fatty acids. The increase in unsaturation was as a result of an increased proportion of n-6 PUFA (particularly arachidonic acid) in the phospholipid and sphingo- plus glycolipid fractions. The triacylglycerol fraction of lipids displayed a negligible change. The proportion of phospholipids within the extracted lipid increased between 26 and 20 C without any change in the lipid content of the fungus. Although the changes in lipid unsaturation correlated, at first inspection, to the culture dissolved O2 tension (DOT), growth of the fungus at a constant dilution rate and temperature (22 C) over a range of DOT values failed to influence lipid unsaturation. Thus temperature is the principal regulation factor of the degree of unsaturation in the lipids of this organism.
Methanol extracts fromChlorococcum strain HS-101 andDunaliella primolecta strongly inhibited the growth of a strain of methicillin-resistantStaphylococcus aureus (MRSA), which is causing serious problems in Japanese hospitals. So that the anti-MRSA substance(s) could be purified and identified, the growth medium was improved for antibiotic production. When the two strains were cultured in their improved media, antibiotic production byChlorococcum strain HS-101 was 1.8-fold that in the standard BG-11 medium, and production byD. primolecta was 2.3-fold. The activity pattern of fractions eluted by silica-gel or gel-permeation chromatography suggested that both strains produced two antibiotic substances. Identification of the purified substances by NMR and GC-MS showed that one of the active substances in both strains was-linolenic acid. Ten fatty acids from other sources were tested, and it was found that unsaturated fatty acids had antibiotic activity against MRSA, with the highest activity that of -linolenic acid.
Changes in growth and fatty acid content ofSpirulina platensis were examined after transferring cells into media containing various concentrations of ammonium chloride. Photosynthetic
O2 evolution rate decreased with increasing ammonium chloride concentration. Therefore, the algal growth was interrupted by
ammonium chloride addition. On the other hand, total fatty acid content markedly increased after addition of ammonium chloride
to a concentration of 15–50 mM and was maximized 40–48 h after addition of 25 mM ammonium chloride. The increases in palmitic
and oleic acid content were especially remarkable. However, this began to decrease 48 h after the addition of 25 mM of ammonium
chloride. Also, γ-linolenic acid content increased continuously during a 72-h incubation. As a result,Spirulina platensis cells containing about 2% γ-linolenic acid were obtained by ammonium chloride treatment, representing an increase of 1.5–2-fold
compared to untreated cells.
Two green algae (Chlorella vulgaris and Scenedesmus obliquus) and four blue-green algae (Anacystis nidulans, Microcystis aeruginosa, Oscillatoria rubescens and Spirulina platensis) were grown in 81 batch cultures at different nitrogen levels. In all the algae increasing N levels led to an increase in the biomass (from 8 to 450 mg/l), in protein content (from 8 to 54 %) and in chlorophyll. At low N levels, the green algae contained a high percentage of total lipids (45 % of the biomass). More than 70 % of these were neutral lipids such as triacylglycerols (containing mainly 16:0 and 18:1 fatty acids) and trace amounts of hydrocarbons. At high N levels, the percentage of total lipids dropped to about 20 % of the dry weight. In the latter case the predominant lipids were polar lipids containing polyunsaturated C16 and C18 fatty acids. The blue-green algae, however, did not show any significant changes in their fatty acid and lipid compositions, when the nitrogen concentrations in the nutrient medium were varied. Thus the green but not the blue-green algae can be manipulated in mass cultures to yield a biomass with desired fatty acid and lipid compositions. The data may indicate a hitherto unrecognized distinction between prokaryotic and eukaryotic organisms.
An autolytic substance in an axenic cyanobacterium, Phormidium tenue, was identified as a mixture of fatty acids, by use of cultured cells in the laboratory. Among them, linoleic acid and linolenic acid were potent growth inhibitors.
In a double-blind trial patients with atopic eczema received either oral evening primrose oil (EPO) (n= 14) or placebo (n= 11) for 12 weeks. In the EPO group a statistically significant improvement was observed in the overall severity and grade of inflammation and in the percentage of the body surface involved by eczema as well as in dryness and itch. Patients in the placebo group showed a significant reduction in inflammation. The patients receiving EPO showed a significantly greater reduction in inflammation than those receiving placebo.
Evening primrose oil caused a significant rise in the amount of dihomogammatinolenic acid in the plasma phospholipid fatty acids. Plasma levels of TXB2, 6-keto-PGF1, and PGE1, and the amount of TXB2 released into serum during clotting were not altered by evening primrose oil.
An increase in linoleic acid intake lowers plasma cholesterol and is one of the safest methods for achieving this end. However, the amounts that must be consumed are large. Linoleic acid is metabolized via several routes and it is probable that a metabolite, rather than linoleic acid itself, is responsible for the cholesterol-lowering effect. If that metabolite could be identified, safe, drug-free, cholesterol-lowering might be achieved with much lower doses. Evidence is reviewed which suggests that a long-chain polyunsaturated fatty acid and/or a prostaglandin metabolite may be responsible for the cholesterol-controlling action of linoleic acid. Such metabolites may be effective also in controlling other risk factors for cardiovascular disease, such as elevated blood pressure and enhanced platelet aggregation. Epidemiological studies suggest that low levels of those metabolites, especially dihomogammalinolenic acid and arachidonic acid, are powerful independent risk factors for development of ischaemic heart disease. Further research in this area is urgently needed now that it is broadly accepted that cholesterol-lowering does indeed reduce the risk of cardiovascular disease.
The clinical and biochemical effects of a prostaglandin synthesis precursor (Efamol) containing linoleic acid and its metabolite, gamma-linolenic acid, were studied in 30 women with severe, incapacitating premenstrual syndrome. Efamol treatment alleviated the premenstrual symptoms in general and depression especially better than did a placebo. The capacity of platelets to release thromboxane B2 during spontaneous clotting was decreased in patients undergoing Efamol treatment (141 +/- 59 ng/ml, mean +/- SD) as compared to those undergoing placebo treatment (186 +/- 44 ng/ml, p less than 0.01) and control subjects (176 +/- 40 ng/ml, n = 25, p less than 0.05). No changes were found in plasma 6-keto-prostaglandin F1alpha or in FSH, LH, prolactin, progesterone, estradiol and testosterone. The data suggest that prostaglandins might play a role in the pathophysiology of the premenstrual syndrome.
For 30 years it has been known that linoleic acid can lower elevated cholesterol levels. Large increases in linoleic acid have been widely recommended as a way of reducing the risk of cardiovascular disease. Such recommendations have resulted in major dietary shifts in some countries, including the USA. Yet the precise characteristics of the linoleic acid molecule which confer on it cholesterol-lowering properties are unknown. gamma-Linolenic acid, the first essential fatty acid metabolite of linoleic acid, has been found to have cholesterol-lowering actions ca. 170 times greater than the parent molecule, suggesting that linoleic acid must be converted to gamma-linolenic acid to exert its desirable effects on cholesterol metabolism. Aging, sex, diabetes mellitus, alcohol, catecholamines and trans fatty acids and saturated fats can all modulate the delta-6-desaturase enzyme which converts linoleic acid to gamma-linolenic acid. This provides a possible unifying explanation for the actions of these known risk factors for cardiovascular disease.
An extract of the cyanobacterium P. tenue showed a significant inhibitory effect on its own growth. Bioassay-directed fractionation has led to the identification of the auto-growth inhibitory substance as a mixture of fatty acids. Unsaturated fatty acids such as linoleic and linolenic acids appear to be predominantly responsible for the auto-growth inhibitory effect.
Gamma-linolenic acid (GLA), a nutritionally important fatty acid in human and animal diets, is not produced in oil seed crops. Many oil seed plants, however, produce significant quantities of linoleic acid, a fatty acid that could be converted to GLA by the enzyme delta 6-desaturase if it were present. As a first step to producing GLA in oil seed crops, we have cloned a cyanobacterial delta 6-desaturase gene. Expression of this gene in transgenic tobacco resulted in GLA accumulation. Octadecatetraenoic acid, a highly unsaturated, industrially important fatty acid, was also found in transgenic tobacco plants expressing the cyanobacterial delta 6-desaturase. This is the first example of engineering the production of 'novel' polyunsaturated fatty acids in transgenic plants.
Cyanobacteria are a very old group of prokaryotic organisms that produce a variety of secondary metabolites with antibiotic, algicide, cytotoxic, immunosuppressive and enzyme inhibiting activities. In the last decades structures of pure compounds have been determined as phenols, peptides, alkaloids or terpenoids (Falch, 1996). Screening of lipophilic and hydrophilic extracts from cultured cyanobacteria or waterbloom material, isolated from German lakes and the Baltic sea for antiviral, antibiotic, immunomodulating and enzyme inhibiting activity in different in vitro systems revealed strains with interesting effects. These strains were cultivated in 45 litre photobioreactors to produce enough biomass for bioassay-guided isolation of the active substances. First results characterising active substances are reported.
Lipid decomposition studies in frozen fish have led to the development of a simple and rapid method for the extraction and purification of lipids from biological materials. The entire procedure can be carried out in approximately 10 minutes; it is efficient, reproducible, and free from deleterious manipulations. The wet tissue is homogenized with a mixture of chloroform and methanol in such proportions that a miscible system is formed with the water in the tissue. Dilution with chloroform and water separates the homogenate into two layers, the chloroform layer containing all the lipids and the methanolic layer containing all the non-lipids. A purified lipid extract is obtained merely by isolating the chloroform layer. The method has been applied to fish muscle and may easily be adapted to use with other tissues.Lipid decomposition studies in frozen fish have led to the development of a simple and rapid method for the extraction and purification of lipids from biological materials. The entire procedure can be carried out in approximately 10 minutes; it is efficient, reproducible, and free from deleterious manipulations. The wet tissue is homogenized with a mixture of chloroform and methanol in such proportions that a miscible system is formed with the water in the tissue. Dilution with chloroform and water separates the homogenate into two layers, the chloroform layer containing all the lipids and the methanolic layer containing all the non-lipids. A purified lipid extract is obtained merely by isolating the chloroform layer. The method has been applied to fish muscle and may easily be adapted to use with other tissues.
The acyl-lipid and fatty acid composition of six blue-green algae, namely,Spirulina platensis, Myxosarcina chroococcoides, Chlorogloea fritschii, Anabaena cylindrica, Anabaena flos-aquae, and Mastigocladus laminosus is reported.
All contain major proportions of mono-and digalactosyl diglyceride, sulfoquinovosyl diglyceride, and phosphatidyl glycerol, but none possess lecithin, phophatidyl ethanolamine, or phosphatidyl inositol. Trans-3-hexadecenoic acid was absent from all extracts.
The analyses provide further evidence that there is no general chemical or physical requirement for any specific fatty acid in photosynthesis.
S. platensis is unique among photoautotrophic organisms so far studied, containing major quantities of γ-linolenic acid (6,9,12-octadecatrienoic acid). This acid is synthesized by the alga by direct desaturation of linoleic acid and is primarily located in the mono- and digalactosyl diglyceride fractions.
The possible phylogenetic relationship betweenS. platensis and other plant forms is discussed.
Auto-growth inhibitory substance from the fresh water cyano-bacterium Phormidium tenue. Chemical and Pharmaceutical Bulle-tin Tokyo 41
- N Yamada
- N Murakami
- T Motimoto
- J Sakakibara
Yamada, N., Murakami, N., Motimoto, T. & Sakakibara, J. 1993 Auto-growth inhibitory substance from the fresh water cyano-bacterium Phormidium tenue. Chemical and Pharmaceutical Bulle-tin Tokyo 41, 1863–1865.
Utilization of individual monosaccharides from their mixtures by the microscopic fungus Cunninghamella japonica and its effect on lipid synthesis Mikrobiologiya
- L A Galanina
- M N Bekhtereva
- T A Pavlova
- E V Tsvetkova
- L.A. Galanina
Phosphate The Biology of Cyanobacteria
- F P Healey
Natural sources and biosynthesis of γ-linolenic acid: an overview γ-Linolenic acid Metabolism and its Roles in Nutrition and Medicine
- J C Phillips
- Y.-S Huang
Screening of γ-linolenic acid producing fungi
- Y C Shin
- H K Shin
- Y.C. Shin
Shin, Y.C. & Shin, H.K. 1988 Screening of c-linolenic acid producing
fungi. Korean Journal of Food Science and Technology 20, 724-731.
Utilization of individual monosaccharides from their mixtures by the microscopic fungus Cunninghamella japonica and its effect on lipid synthesis
- T V Desikachary
- L A Galanina
- M N Bekhtereva
- T A Pavlova
- E Tsvetkova
Desikachary, T.V. 1959 Cyanophyta, p. 599, India: ICAR Publication.
Galanina, L.A., Bekhtereva, M.N., Pavlova, T.A. & Tsvetkova, E.V.
1988 Utilization of individual monosaccharides from their mixtures by the microscopic fungus Cunninghamella japonica and its
effect on lipid synthesis. Mikrobiologiya 57, 213-217.
- E W Becker
Becker, E.W. 1994 Microalgae. Biotechnology and Microbiology,
Cambridge: Cambridge University Press, ISBN 0-521-35020-4.
Expression of a borage desaturase cDNA containing an N-terminal cytochrome b 5 domain results in the accumulation of high levels of D 6-desaturated fatty acids in transgenic tobacco
- O Sayanova
- M A Smith
- P Lapinskas
- K Stobart
- G Dobson
- W W Christie
- P R Shewry
- J A Napier
Sayanova, O., Smith, M.A., Lapinskas, P., Stobart, K., Dobson, G.,
Christie, W.W., Shewry, P.R. & Napier, J.A. 1997 Expression of a
borage desaturase cDNA containing an N-terminal cytochrome b 5
domain results in the accumulation of high levels of D 6-desaturated
fatty acids in transgenic tobacco. Proceedings of the National
Academy of Sciences, USA 94, 4211-4216.
The lipids of the alga
- B J F Hudson
- I G Karris
- B.J.F. Hudson
(eds). γ-Linolenic acid Metabolism and its Roles in Nutrition and Medicine
- J C Phillips
- Y.-S Huang
- J.C. Phillips
Etude comparee des lipids, de Spirulina platensis (Gom.) Geitler et de Spirulina geitleri J. de Toni. Comptes Rendues Hebdomaires des Séances de l’Academie des Sciences
- A Pelloquin
- R Lai
- F Busson
- A. Pelloquin