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Journal articles on the topic 'Marine photosynthetic organisms'
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1
Kumar, Amit, Immacolata Castellano, Francesco Paolo Patti, Anna Palumbo, and Maria Cristina Buia. "Nitric oxide in marine photosynthetic organisms." Nitric Oxide 47 (May 2015): 34–39. http://dx.doi.org/10.1016/j.niox.2015.03.001.
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Singh, Dipali, Ross Carlson, David Fell, and Mark Poolman. "Modelling metabolism of the diatom Phaeodactylum tricornutum." Biochemical Society Transactions 43, no. 6 (November 27, 2015): 1182–86. http://dx.doi.org/10.1042/bst20150152.
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Marine diatoms have potential as a biotechnological production platform, especially for lipid-derived products, including biofuels. Here we introduce some features of diatom metabolism, particularly with respect to photosynthesis, photorespiration and lipid synthesis and their differences relative to other photosynthetic eukaryotes. Since structural metabolic modelling of other photosynthetic organisms has been shown to be capable of representing their metabolic capabilities realistically, we briefly review the main approaches to this type of modelling. We then propose that genome-scale modelling of the diatom Phaeodactylum tricornutum, in response to varying light intensity, could uncover the novel aspects of the metabolic potential of this organism.
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Avila-Alonso, Dailé, Jan M. Baetens, Rolando Cardenas, and Bernard De Baets. "Assessing the effects of ultraviolet radiation on the photosynthetic potential in Archean marine environments." International Journal of Astrobiology 16, no. 3 (September 9, 2016): 271–79. http://dx.doi.org/10.1017/s147355041600032x.
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AbstractIn this work, the photosynthesis model presented by Avilaet al. in 2013 is extended and more scenarios inhabited by ancient cyanobacteria are investigated to quantify the effects of ultraviolet (UV) radiation on their photosynthetic potential in marine environments of the Archean eon. We consider ferrous ions as blockers of UV during the Early Archean, while the absorption spectrum of chlorophyllais used to quantify the fraction of photosynthetically active radiation absorbed by photosynthetic organisms. UV could have induced photoinhibition at the water surface, thereby strongly affecting the species with low light use efficiency. A higher photosynthetic potential in early marine environments was shown than in the Late Archean as a consequence of the attenuation of UVC and UVB by iron ions, which probably played an important role in the protection of ancient free-floating bacteria from high-intensity UV radiation. Photosynthetic organisms in Archean coastal and ocean environments were probably abundant in the first 5 and 25 m of the water column, respectively. However, species with a relatively high efficiency in the use of light could have inhabited ocean waters up to a depth of 200 m and show a Deep Chlorophyll Maximum near 60 m depth. We show that the electromagnetic radiation from the Sun, both UV and visible light, could have determined the vertical distribution of Archean marine photosynthetic organisms.
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Coelho, Susana M., Nathalie Simon, Sophia Ahmed, J. Mark Cock, and Frédéric Partensky. "Ecological and evolutionary genomics of marine photosynthetic organisms." Molecular Ecology 22, no. 3 (September 18, 2012): 867–907. http://dx.doi.org/10.1111/mec.12000.
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Giomi, Folco, Alberto Barausse, Carlos M. Duarte, Jenny Booth, Susana Agusti, Vincent Saderne, Andrea Anton, Daniele Daffonchio, and Marco Fusi. "Oxygen supersaturation protects coastal marine fauna from ocean warming." Science Advances 5, no. 9 (September 2019): eaax1814. http://dx.doi.org/10.1126/sciadv.aax1814.
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Ocean warming affects the life history and fitness of marine organisms by, among others, increasing animal metabolism and reducing oxygen availability. In coastal habitats, animals live in close association with photosynthetic organisms whose oxygen supply supports metabolic demands and may compensate for acute warming. Using a unique high-frequency monitoring dataset, we show that oxygen supersaturation resulting from photosynthesis closely parallels sea temperature rise during diel cycles in Red Sea coastal habitats. We experimentally demonstrate that oxygen supersaturation extends the survival to more extreme temperatures of six species from four phyla. We clarify the mechanistic basis of the extended thermal tolerance by showing that hyperoxia fulfills the increased metabolic demand at high temperatures. By modeling 1 year of water temperatures and oxygen concentrations, we predict that oxygen supersaturation from photosynthetic activity invariably fuels peak animal metabolic demand, representing an underestimated factor of resistance and resilience to ocean warming in ectotherms.
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Folmer, F., M. Jaspars, M. Dicato, and M. Diederich. "Photosynthetic marine organisms as a source of anticancer compounds." Phytochemistry Reviews 9, no. 4 (October 15, 2010): 557–79. http://dx.doi.org/10.1007/s11101-010-9200-2.
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Birringer, Marc, Karsten Siems, Alexander Maxones, Jan Frank, and Stefan Lorkowski. "Natural 6-hydroxy-chromanols and -chromenols: structural diversity, biosynthetic pathways and health implications." RSC Advances 8, no. 9 (2018): 4803–41. http://dx.doi.org/10.1039/c7ra11819h.
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We present the first comprehensive and systematic review on the structurally diverse toco-chromanols and -chromenols found in photosynthetic organisms, including marine organisms, and as metabolic intermediates in animals.
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Lefranc, Florence, Aikaterini Koutsaviti, Efstathia Ioannou, Alexander Kornienko, Vassilios Roussis, Robert Kiss, and David Newman. "Algae metabolites: fromin vitrogrowth inhibitory effects to promising anticancer activity." Natural Product Reports 36, no. 5 (2019): 810–41. http://dx.doi.org/10.1039/c8np00057c.
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Pereira, Leonel. "Macroalgae." Encyclopedia 1, no. 1 (February 7, 2021): 177–88. http://dx.doi.org/10.3390/encyclopedia1010017.
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What are algae? Algae are organisms that perform photosynthesis; that is, they absorb carbon dioxide and release oxygen (therefore they have chlorophyll, a group of green pigments used by photosynthetic organisms that convert sunlight into energy via photosynthesis) and live in water or in humid places. Algae have great variability and are divided into microalgae, small in size and only visible through a microscope, and macroalgae, which are larger in size, up to more than 50 m (the maximum recorded was 65 m), and have a greater diversity in the oceans. Thus, the term “algae” is commonly used to refer to “marine macroalgae or seaweeds”. It is estimated that 1800 different brown macroalgae, 6200 red macroalgae, and 1800 green macroalgae are found in the marine environment. Although the red algae are more diverse, the brown ones are the largest.
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Raven, John A., and John Beardall. "Energizing the plasmalemma of marine photosynthetic organisms: the role of primary active transport." Journal of the Marine Biological Association of the United Kingdom 100, no. 3 (April 13, 2020): 333–46. http://dx.doi.org/10.1017/s0025315420000211.
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AbstractGeneration of ion electrochemical potential differences by primary active transport can involve energy inputs from light, from exergonic redox reactions and from exergonic ATP hydrolysis. These electrochemical potential differences are important for homoeostasis, for signalling, and for energizing nutrient influx. The three main ions involved are H+, Na+ (efflux) and Cl− (influx). In prokaryotes, fluxes of all three of these ions are energized by ion-pumping rhodopsins, with one archaeal rhodopsin pumping H+into the cells; among eukaryotes there is also an H+ influx rhodopsin in Acetabularia and (probably) H+ efflux in diatoms. Bacteriochlorophyll-based photoreactions export H+ from the cytosol in some anoxygenic photosynthetic bacteria, but chlorophyll-based photoreactions in marine cyanobacteria do not lead to export of H+. Exergonic redox reactions export H+ and Na+ in photosynthetic bacteria, and possibly H+ in eukaryotic algae. P-type H+- and/or Na+-ATPases occur in almost all of the photosynthetic marine organisms examined. P-type H+-efflux ATPases occur in charophycean marine algae and flowering plants whereas P-type Na+-ATPases predominate in other marine green algae and non-green algae, possibly with H+-ATPases in some cases. An F-type Cl−-ATPase is known to occur in Acetabularia. Some assignments, on the basis of genomic evidence, of P-type ATPases to H+ or Na+ as the pumped ion are inconclusive.
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Genç, Yasin, Hilal Bardakci, Çiğdem Yücel, Gökçe Şeker Karatoprak, Esra Küpeli Akkol, Timur Hakan Barak, and Eduardo Sobarzo-Sánchez. "Oxidative Stress and Marine Carotenoids: Application by Using Nanoformulations." Marine Drugs 18, no. 8 (August 13, 2020): 423. http://dx.doi.org/10.3390/md18080423.
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Carotenoids are natural fat-soluble pigments synthesized by plants, algae, fungi and microorganisms. They are responsible for the coloration of different photosynthetic organisms. Although they play a role in photosynthesis, they are also present in non-photosynthetic plant tissues, fungi, and bacteria. These metabolites have mainly been used in food, cosmetics, and the pharmaceutical industry. In addition to their utilization as pigmentation, they have significant therapeutically applications, such as improving immune system and preventing neurodegenerative diseases. Primarily, they have attracted attention due to their antioxidant activity. Several statistical investigations indicated an association between the use of carotenoids in diets and a decreased incidence of cancer types, suggesting the antioxidant properties of these compounds as an important factor in the scope of the studies against oxidative stress. Unusual marine environments are associated with a great chemical diversity, resulting in novel bioactive molecules. Thus, marine organisms may represent an important source of novel biologically active substances for the development of therapeutics. Marine carotenoids (astaxanthin, fucoxanthin, β-carotene, lutein but also the rare siphonaxanthin, sioxanthin, and myxol) have recently shown antioxidant properties in reducing oxidative stress markers. Numerous of bioactive compounds such as marine carotenoids have low stability, are poorly absorbed, and own very limited bioavailability. The new technique is nanoencapsulation, which can be used to preserve marine carotenoids and their original properties during processing, storage, improve their physiochemical properties and increase their health-promoting effects. This review aims to describe the role of marine carotenoids, their potential applications and different types of advanced nanoformulations preventing and treating oxidative stress related disorders.
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Schorsch, Michael, Manuela Kramer, Tatjana Goss, Marion Eisenhut, Nigel Robinson, Deenah Osman, Annegret Wilde, et al. "A unique ferredoxin acts as a player in the low-iron response of photosynthetic organisms." Proceedings of the National Academy of Sciences 115, no. 51 (December 4, 2018): E12111—E12120. http://dx.doi.org/10.1073/pnas.1810379115.
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Iron chronically limits aquatic photosynthesis, especially in marine environments, and the correct perception and maintenance of iron homeostasis in photosynthetic bacteria, including cyanobacteria, is therefore of global significance. Multiple adaptive mechanisms, responsive promoters, and posttranscriptional regulators have been identified, which allow cyanobacteria to respond to changing iron concentrations. However, many factors remain unclear, in particular, how iron status is perceived within the cell. Here we describe a cyanobacterial ferredoxin (Fed2), with a unique C-terminal extension, that acts as a player in iron perception. Fed2 homologs are highly conserved in photosynthetic organisms from cyanobacteria to higher plants, and, although they belong to the plant type ferredoxin family of [2Fe-2S] photosynthetic electron carriers, they are not involved in photosynthetic electron transport. As deletion offed2appears lethal, we developed a C-terminal truncation system to attenuate protein function. Disturbed Fed2 function resulted in decreased chlorophyll accumulation, and this was exaggerated in iron-depleted medium, where different truncations led to either exaggerated or weaker responses to low iron. Despite this, iron concentrations remained the same, or were elevated in all truncation mutants. Further analysis established that, when Fed2 function was perturbed, the classical iron limitation marker IsiA failed to accumulate at transcript and protein levels. By contrast, abundance of IsiB, which shares an operon withisiA, was unaffected by loss of Fed2 function, pinpointing the site of Fed2 action in iron perception to the level of posttranscriptional regulation.
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Rasmusson, Lina M., Aekkaraj Nualla-ong, Tarawit Wutiruk, Mats Björk, Martin Gullström, and Pimchanok Buapet. "Sensitivity of Photosynthesis to Warming in Two Similar Species of the Aquatic Angiosperm Ruppia from Tropical and Temperate Habitats." Sustainability 13, no. 16 (August 23, 2021): 9433. http://dx.doi.org/10.3390/su13169433.
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Climate change-related events, such as marine heatwaves, are increasing seawater temperatures, thereby putting pressure on marine biota. The cosmopolitan distribution and significant contribution to marine primary production by the genus Ruppia makes them interesting organisms to study thermal tolerance and local adaptation. In this study, we investigated the photosynthetic responses in Ruppia to the predicted future warming in two contrasting bioregions, temperate Sweden and tropical Thailand. Through DNA barcoding, specimens were determined to Ruppia cirrhosa for Sweden and Ruppia maritima for Thailand. Photosynthetic responses were assessed using pulse amplitude-modulated fluorometry, firstly in short time incubations at 18, 23, 28, and 33 °C in the Swedish set-up and 28, 33, 38, and 43 °C in the Thai set-up. Subsequent experiments were conducted to compare the short time effects to longer, five-day incubations in 28 °C for Swedish plants and 40 °C for Thai plants. Swedish R. cirrhosa displayed minor response, while Thai R. maritima was more sensitive to both direct and prolonged temperature stress with a drastic decrease in the photosynthetic parameters leading to mortality. The results indicate that in predicted warming scenarios, Swedish R. cirrhosa may sustain an efficient photosynthesis and potentially outcompete more heat-sensitive species. However, populations of the similar R. maritima in tropical environments may suffer a decline as their productivity will be highly reduced.
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Higuchi-Takeuchi, Mieko, Takaaki Miyamoto, Choon Pin Foong, Mami Goto, Kumiko Morisaki, and Keiji Numata. "Peptide-Mediated Gene Transfer into Marine Purple Photosynthetic Bacteria." International Journal of Molecular Sciences 21, no. 22 (November 16, 2020): 8625. http://dx.doi.org/10.3390/ijms21228625.
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Use of photosynthetic organisms is one of the sustainable ways to produce high-value products. Marine purple photosynthetic bacteria are one of the research focuses as microbial production hosts. Genetic transformation is indispensable as a biotechnology technique. However, only conjugation has been determined to be an applicable method for the transformation of marine purple photosynthetic bacteria so far. In this study, for the first time, a dual peptide-based transformation method combining cell penetrating peptide (CPP), cationic peptide and Tat-derived peptide (dTat-Sar-EED) (containing D-amino acids of Tat and endosomal escape domain (EED) connected by sarcosine linkers) successfully delivered plasmid DNA into Rhodovulum sulfidophilum, a marine purple photosynthetic bacterium. The plasmid delivery efficiency was greatly improved by dTat-Sar-EED. The concentrations of dTat-Sar-EED, cell growth stage and recovery duration affected the efficiency of plasmid DNA delivery. The delivery was inhibited at 4 °C and by A22, which is an inhibitor of the actin homolog MreB. This suggests that the plasmid DNA delivery occurred via MreB-mediated energy dependent process. Additionally, this peptide-mediated delivery method was also applicable for E. coli cells. Thus, a wide range of bacteria could be genetically transformed by using this novel peptide-based transformation method.
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Hackenberg, Claudia, Johanna Hakanpää, Fei Cai, Svetlana Antonyuk, Caroline Eigner, Sven Meissner, Mikko Laitaoja, et al. "Structural and functional insights into the unique CBS–CP12 fusion protein family in cyanobacteria." Proceedings of the National Academy of Sciences 115, no. 27 (June 18, 2018): 7141–46. http://dx.doi.org/10.1073/pnas.1806668115.
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Cyanobacteria are important photosynthetic organisms inhabiting a range of dynamic environments. This phylum is distinctive among photosynthetic organisms in containing genes encoding uncharacterized cystathionine β-synthase (CBS)–chloroplast protein (CP12) fusion proteins. These consist of two domains, each recognized as stand-alone photosynthetic regulators with different functions described in cyanobacteria (CP12) and plants (CP12 and CBSX). Here we show that CBS–CP12 fusion proteins are encoded in distinct gene neighborhoods, several unrelated to photosynthesis. Most frequently, CBS–CP12 genes are in a gene cluster with thioredoxin A (TrxA), which is prevalent in bloom-forming, marine symbiotic, and benthic mat cyanobacteria. Focusing on a CBS–CP12 fromMicrocystis aeruginosaPCC 7806 encoded in a gene cluster with TrxA, we reveal that the domain fusion led to the formation of a hexameric protein. We show that the CP12 domain is essential for hexamerization and contains an ordered, previously structurally uncharacterized N-terminal region. We provide evidence that CBS–CP12, while combining properties of both regulatory domains, behaves different from CP12 and plant CBSX. It does not form a ternary complex with phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase. Instead, CBS–CP12 decreases the activity of PRK in an AMP-dependent manner. We propose that the novel domain architecture and oligomeric state of CBS–CP12 expand its regulatory function beyond those of CP12 in cyanobacteria.
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Gray, Ira, Lindsay A. Green-Gavrielidis, and Carol Thornber. "Effect of caffeine on the growth and photosynthetic efficiency of marine macroalgae." Botanica Marina 64, no. 1 (January 13, 2021): 13–18. http://dx.doi.org/10.1515/bot-2020-0055.
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Abstract Caffeine is present in coastal environments worldwide and there is a need to assess its impact on marine organisms. Here, we exposed two species of ecologically important marine macroalgae (Chondrus crispus and Codium fragile subsp. fragile) to a suite of caffeine concentrations and measured their response. Caffeine concentrations of 10–100 ng L−1 had no significant effect on the growth rate or photosynthetic efficiency of either algae. Extremely high concentrations (100–200 mg L−1), which may occur acutely, produced sublethal effects for both species and mortality in C. fragile subsp. fragile. Our results highlight the need to understand how caffeine impacts marine species.
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Raven, John A., and Ramon D. Wolstencroft. "Constraints on Photosynthesis on Earth and Earth-Like Planets." Symposium - International Astronomical Union 213 (2004): 305–8. http://dx.doi.org/10.1017/s0074180900193453.
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We discuss how the spectral mismatch between solar radiation at the Earth's surface and the two absorption maxima (440 and 680 nm) of the dominant chlorophyll pigments can be explained as an evolutionary accident of the marine habitat in which photosynthesis evolved on Earth. The geometric rigidity and great stability of chlorophyll make it a likely “universal pigment” given this, together with the spectral absorption properties of water, the evolution of photosynthesis on Earth-like planets (ELPs) orbiting in the habitable zones of A, F and G stars should be relatively straightforward. However for ELPs orbiting cool K and M stars, the effects of variable UV emission from the ELP at earlier epochs and the high absorption of red light by water could lead to a “feast and famine” existence for photosynthetic organisms in the ELP ocean. Pull exploitation of the cool star radiation when UV activity has declined may lead to an evolution of the photosynthetic machinery from the terrestrial two photon to a three photon system.
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Schneider, Geniane, Félix L. Figueroa, Julia Vega, Patricia Chaves, Félix Álvarez-Gómez, Nathalie Korbee, and José Bonomi-Barufi. "Photoprotection properties of marine photosynthetic organisms grown in high ultraviolet exposure areas: Cosmeceutical applications." Algal Research 49 (August 2020): 101956. http://dx.doi.org/10.1016/j.algal.2020.101956.
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De Luca, Daniele, and Chiara Lauritano. "In Silico Identification of Type III PKS Chalcone and Stilbene Synthase Homologs in Marine Photosynthetic Organisms." Biology 9, no. 5 (May 22, 2020): 110. http://dx.doi.org/10.3390/biology9050110.
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Marine microalgae are photosynthetic microorganisms at the base of the marine food webs. They are characterized by huge taxonomic and metabolic diversity and several species have been shown to have bioactivities useful for the treatment of human pathologies. However, the compounds and the metabolic pathways responsible for bioactive compound synthesis are often still unknown. In this study, we aimed at analysing the microalgal transcriptomes available in the Marine Microbial Eukaryotic Transcriptome Sequencing Project (MMETSP) database for an in silico search of polyketide synthase type III homologs and, in particular, chalcone synthase (CHS) and stilbene synthase (STS), which are often referred to as the CHS/STS family. These enzymes were selected because they are known to produce compounds with biological properties useful for human health, such as cancer chemopreventive, anti-inflammatory, antioxidant, anti-angiogenic, anti-viral and anti-diabetic. In addition, we also searched for 4-Coumarate: CoA ligase, an upstream enzyme in the synthesis of chalcones and stilbenes. This study reports for the first time the occurrence of these enzymes in specific microalgal taxa, confirming the importance for microalgae of these pathways and giving new insights into microalgal physiology and possible biotechnological applications for the production of bioactive compounds.
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Morel, François M. M., Phoebe J. Lam, and Mak A. Saito. "Trace Metal Substitution in Marine Phytoplankton." Annual Review of Earth and Planetary Sciences 48, no. 1 (May 30, 2020): 491–517. http://dx.doi.org/10.1146/annurev-earth-053018-060108.
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The sinking of organic matter to the deep ocean leaves extremely low concentrations of major and trace nutrients for photosynthetic organisms at the sunlit surface. As a result, marine phytoplankton make use of alternative sources of essential elements and have evolved to substitute some elements by others in various biochemical processes. A particularly intriguing example is that of Zn, which is used in many biochemical functions but is often depleted down to picomolar concentrations in surface seawater. Laboratory data show that many phytoplankton species are able to achieve high growth rates by replacing Zn with Cd or Co in cultures. One documented biochemical replacement occurs in some carbonic anhydrases that are used in the acquisition of inorganic carbon for photosynthesis. Field data show the existence of such enzymes in surface seawater and indicate a replacement of Zn by Cd and Co in the surface waters of the eastern tropical South Pacific. Those results point at interesting opportunities for future research. ▪ The dearth of essential elements in surface seawater has caused marine phytoplankton to substitute some trace metals by others in various biochemical processes. ▪ Many species can substitute Cd and/or Co for Zn as a metal center in carbonic anhydrase enzymes that are used in the acquisition of inorganic carbon for photosynthesis. ▪ Field data show the presence of such enzymes in the sea and indicate a replacement of Zn by Cd and Co in the surface upwelling waters of the eastern tropical South Pacific. ▪ New analytical and molecular tools provide opportunities to elucidate the unusual biochemistry of marine phytoplankton.
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Handayani, Tri. "PERANAN EKOLOGI MAKROALGA BAGI EKOSISTEM LAUT." OSEANA 44, no. 1 (November 15, 2019): 1–14. http://dx.doi.org/10.14203/oseana.2019.vol.44no.1.25.
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ECOLOGICAL ROLE OF MACROALGAE FOR MARINE ECOSYSTEM. Macroalgae is an ecologically and economically important component in marine ecosystem. Ecologically, macroalgae has a role as a primary producer, food for other marine biota, provide shelter, nursery ground and carbon sink. Macroalgae contains photosynthetic pigments to be able to provide their own food and produce carbon dioxide for other marine biota (called primary productivity). Macroalgae is a food source, provide shelter and nursery ground for fish, gastropods (mollusks), crustaceans and sea urchins. Macroalgae also has the ability to to reduce the effects of global warming through carbon sink. Absorption of carbon emissions of anthropogenic activity by marine organisms are called as blue carbon. Therefore, macroalgae is ecologically importantfor the balancing of marine ecosystems sustainability.
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Gattuso, JP, M. Pichon, and M. Frankignoulle. "Biological control of air-sea CO2 fluxes:effect of photosynthetic and calcifying marine organisms and ecosystems." Marine Ecology Progress Series 129 (1995): 307–12. http://dx.doi.org/10.3354/meps129307.
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Kram, S. L., N. N. Price, E. M. Donham, M. D. Johnson, E. L. A. Kelly, S. L. Hamilton, and J. E. Smith. "Variable responses of temperate calcified and fleshy macroalgae to elevated pCO2 and warming." ICES Journal of Marine Science 73, no. 3 (September 25, 2015): 693–703. http://dx.doi.org/10.1093/icesjms/fsv168.
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Abstract Anthropogenic carbon dioxide (CO2) emissions simultaneously increase ocean temperatures and reduce ocean surface pH, a process termed ocean acidification (OA). OA is expected to negatively affect the growth and physiology of many calcified organisms, but the response of non-calcified (fleshy) organisms is less well understood. Rising temperatures and pCO2 can enhance photosynthetic rates (within tolerance limits). Therefore, warming may interact with OA to alter biological responses of macroalgae in complicated ways. Beyond thresholds of physiological tolerance, however, rising temperatures could further exacerbate negative responses to OA. Many studies have investigated the effects of OA or warming independently of each other, but few studies have quantified the interactive effects of OA and warming on marine organisms. We conducted four short-term independent factorial CO2 enrichment and warming experiments on six common species of calcified and fleshy macroalgae from southern California to investigate the independent and interactive effects of CO2 and warming on growth, carbonic anhydrase (CA) enzyme activity, pigment concentrations, and photosynthetic efficiency. There was no effect of elevated pCO2 on CA activity, pigment concentration, and photosynthetic efficiency in the macroalgal species studies. However, we found that calcareous algae suffered reduced growth rates under high pCO2 conditions alone, although the magnitude of the effect varied by species. Fleshy algae had mixed responses of growth rates to high pCO2, indicating that the effects of pCO2 enrichment are inconsistent across species. The combined effects of elevated pCO2 and warming had a significantly negative impact on growth for both fleshy and calcareous algae; calcareous algae experienced five times more weight loss than specimens in ambient control conditions and fleshy growth was reduced by 76%. Our results demonstrate the need to study the interactive effects of multiple stressors associated with global change on marine communities.
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Leles, S. G., A. Mitra, K. J. Flynn, D. K. Stoecker, P. J. Hansen, A. Calbet, G. B. McManus, et al. "Oceanic protists with different forms of acquired phototrophy display contrasting biogeographies and abundance." Proceedings of the Royal Society B: Biological Sciences 284, no. 1860 (August 2, 2017): 20170664. http://dx.doi.org/10.1098/rspb.2017.0664.
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This first comprehensive analysis of the global biogeography of marine protistan plankton with acquired phototrophy shows these mixotrophic organisms to be ubiquitous and abundant; however, their biogeography differs markedly between different functional groups. These mixotrophs, lacking a constitutive capacity for photosynthesis (i.e. non-constitutive mixotrophs, NCMs), acquire their phototrophic potential through either integration of prey-plastids or through endosymbiotic associations with photosynthetic microbes. Analysis of field data reveals that 40–60% of plankton traditionally labelled as (non-phototrophic) microzooplankton are actually NCMs, employing acquired phototrophy in addition to phagotrophy. Specialist NCMs acquire chloroplasts or endosymbionts from specific prey, while generalist NCMs obtain chloroplasts from a variety of prey. These contrasting functional types of NCMs exhibit distinct seasonal and spatial global distribution patterns. Mixotrophs reliant on ‘stolen’ chloroplasts, controlled by prey diversity and abundance, dominate in high-biomass areas. Mixotrophs harbouring intact symbionts are present in all waters and dominate particularly in oligotrophic open ocean systems. The contrasting temporal and spatial patterns of distribution of different mixotroph functional types across the oceanic provinces, as revealed in this study, challenges traditional interpretations of marine food web structures. Mixotrophs with acquired phototrophy (NCMs) warrant greater recognition in marine research.
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Toledo, Gerardo, B. Palenik, and B. Brahamsha. "Swimming Marine Synechococcus Strains with Widely Different Photosynthetic Pigment Ratios Form a Monophyletic Group." Applied and Environmental Microbiology 65, no. 12 (December 1, 1999): 5247–51. http://dx.doi.org/10.1128/aem.65.12.5247-5251.1999.
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ABSTRACT Unicellular marine cyanobacteria are ubiquitous in both coastal and oligotrophic regimes. The contribution of these organisms to primary production and nutrient cycling is substantial on a global scale. Natural populations of marine Synechococcus strains include multiple genetic lineages, but the link, if any, between unique phenotypic traits and specific genetic groups is still not understood. We studied the genetic diversity (as determined by the DNA-dependent RNA polymerase rpoC1 gene sequence) of a set of marineSynechococcus isolates that are able to swim. Our results show that these isolates form a monophyletic group. This finding represents the first example of correspondence between a physiological trait and a phylogenetic group in marine Synechococcus. In contrast, the phycourobilin (PUB)/phycoerythrobilin (PEB) pigment ratios of members of the motile clade varied considerably. An isolate obtained from the California Current (strain CC9703) displayed a pigment signature identical to that of nonmotile strain WH7803, which is considered a model for low-PUB/PEB-ratio strains, whereas several motile strains had higher PUB/PEB ratios than strain WH8103, which is considered a model for high-PUB/PEB-ratio strains. These findings indicate that the PUB/PEB pigment ratio is not a useful characteristic for defining phylogenetic groups of marine Synechococcusstrains.
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Lopez, Pascal Jean. "Silicomics: Silicon enters the 'omics arena." Biochemist 33, no. 3 (June 1, 2011): 26–28. http://dx.doi.org/10.1042/bio03303026.
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Silicon is the second most abundant element in the Earth's crust, making up about onequarter of the crust by mass. In the modern surface waters of recent oceans, silicon is undersaturated, but it is estimated that its concentration was much higher before the rise of the diatoms during the Jurassic–Cretaceous periods. Since silicon is everywhere, it is not surpris ing that, over time, a large number of marine and terrestrial organisms have acquired or developed the ability to use or to transform silicon. It is generally known that many organisms accumulate and/or use silicon to construct inter nal or external skeletons. One such organism is diatoms, a class of photosynthetic microalgae capable of creating beautiful threedimensional silica structures, called frustules. The importance of silicon has also been demonstrated by numerous studies in plants showing that silicon improves the resistance to diseases and mitigates other biotic or abiotic stresses. In this article, I highlight selected studies that aimed to understand the meta bolism of silicon, with a particular emphasis on the diatoms.
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Pradhan, Biswajita, Rabindra Nayak, Srimanta Patra, Bimal Prasad Jit, Andrea Ragusa, and Mrutyunjay Jena. "Bioactive Metabolites from Marine Algae as Potent Pharmacophores against Oxidative Stress-Associated Human Diseases: A Comprehensive Review." Molecules 26, no. 1 (December 23, 2020): 37. http://dx.doi.org/10.3390/molecules26010037.
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In addition to cancer and diabetes, inflammatory and ROS-related diseases represent one of the major health problems worldwide. Currently, several synthetic drugs are used to reduce oxidative stress; nevertheless, these approaches often have side effects. Therefore, to overcome these issues, the search for alternative therapies has gained importance in recent times. Natural bioactive compounds have represented, and they still do, an important source of drugs with high therapeutic efficacy. In the “synthetic” era, terrestrial and aquatic photosynthetic organisms have been shown to be an essential source of natural compounds, some of which might play a leading role in pharmaceutical drug development. Marine organisms constitute nearly half of the worldwide biodiversity. In the marine environment, algae, seaweeds, and seagrasses are the first reported sources of marine natural products for discovering novel pharmacophores. The algal bioactive compounds are a potential source of novel antioxidant and anticancer (through modulation of the cell cycle, metastasis, and apoptosis) compounds. Secondary metabolites in marine Algae, such as phenolic acids, flavonoids, and tannins, could have great therapeutic implications against several diseases. In this context, this review focuses on the diversity of functional compounds extracted from algae and their potential beneficial effects in fighting cancer, diabetes, and inflammatory diseases.
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Buick, Roger. "When did oxygenic photosynthesis evolve?" Philosophical Transactions of the Royal Society B: Biological Sciences 363, no. 1504 (May 9, 2008): 2731–43. http://dx.doi.org/10.1098/rstb.2008.0041.
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The atmosphere has apparently been oxygenated since the ‘Great Oxidation Event’ ca 2.4 Ga ago, but when the photosynthetic oxygen production began is debatable. However, geological and geochemical evidence from older sedimentary rocks indicates that oxygenic photosynthesis evolved well before this oxygenation event. Fluid-inclusion oils in ca 2.45 Ga sandstones contain hydrocarbon biomarkers evidently sourced from similarly ancient kerogen, preserved without subsequent contamination, and derived from organisms producing and requiring molecular oxygen. Mo and Re abundances and sulphur isotope systematics of slightly older (2.5 Ga) kerogenous shales record a transient pulse of atmospheric oxygen. As early as ca 2.7 Ga, stromatolites and biomarkers from evaporative lake sediments deficient in exogenous reducing power strongly imply that oxygen-producing cyanobacteria had already evolved. Even at ca 3.2 Ga, thick and widespread kerogenous shales are consistent with aerobic photoautrophic marine plankton, and U–Pb data from ca 3.8 Ga metasediments suggest that this metabolism could have arisen by the start of the geological record. Hence, the hypothesis that oxygenic photosynthesis evolved well before the atmosphere became permanently oxygenated seems well supported.
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Sharma, Lilianna, Grzegorz Siedlewicz, and Ksenia Pazdro. "The Toxic Effects of Antibiotics on Freshwater and Marine Photosynthetic Microorganisms: State of the Art." Plants 10, no. 3 (March 21, 2021): 591. http://dx.doi.org/10.3390/plants10030591.
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Antibiotic residues have been commonly detected worldwide in freshwater, estuarine, and marine ecosystems. The review summarizes the up-to-date information about the toxic effects of over 60 antibiotics on nontarget autotrophic microorganisms with a particular focus on marine microalgae. A comprehensive overview of the available reports led to the identification of significant knowledge gaps. The data on just one species of freshwater green algae (Raphidocelis subcapitata) constitute 60% of the total information on the toxicity of antibiotics, while data on marine species account for less than 14% of the reports. Moreover, there is a clear knowledge gap regarding the chronic effects of antibiotic exposure (only 9% of studies represent exposition time values longer than 7 days). The review summarizes the information on different physiological endpoints, including processes involved in photosynthesis, photoprotective and antioxidant mechanisms. Currently, the hazard assessment is mostly based on the results of the evaluation of individual chemicals and acute toxicity tests of freshwater organisms. Future research trends should involve chronic effect studies incorporating sensitive endpoints with the application of environmentally relevant concentrations, as well as studies on the mixture effects and combined environmental factors influencing toxicity.
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Wu, Ni, Mengmeng Tong, Siyu Gou, Weiji Zeng, Zhuoyun Xu, and Tianjiu Jiang. "Hemolytic Activity in Relation to the Photosynthetic System in Chattonella marina and Chattonella ovata." Marine Drugs 19, no. 6 (June 12, 2021): 336. http://dx.doi.org/10.3390/md19060336.
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Chattonella species, C. marina and C. ovata, are harmful raphidophycean flagellates known to have hemolytic effects on many marine organisms and resulting in massive ecological damage worldwide. However, knowledge of the toxigenic mechanism of these ichthyotoxic flagellates is still limited. Light was reported to be responsible for the hemolytic activity (HA) of Chattonella species. Therefore, the response of photoprotective, photosynthetic accessory pigments, the photosystem II (PSII) electron transport chain, as well as HA were investigated in non-axenic C. marina and C. ovata cultures under variable environmental conditions (light, iron and addition of photosynthetic inhibitors). HA and hydrogen peroxide (H2O2) were quantified using erythrocytes and pHPA assay. Results confirmed that% HA of Chattonella was initiated by light, but was not always elicited during cell division. Exponential growth of C. marina and C. ovata under the light over 100 µmol m−2 s−1 or iron-sufficient conditions elicited high hemolytic activity. Inhibitors of PSII reduced the HA of C. marina, but had no effect on C. ovata. The toxicological response indicated that HA in Chattonella was not associated with the photoprotective system, i.e., xanthophyll cycle and regulation of reactive oxygen species, nor the PSII electron transport chain, but most likely occurred during energy transport through the light-harvesting antenna pigments. A positive, highly significant relationship between HA and chlorophyll (chl) biosynthesis pigments, especially chl c2 and chl a, in both species, indicated that hemolytic toxin may be generated during electron/energy transfer through the chl c2 biosynthesis pathway.
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Hussein, Hanaa Ali, and Mohd Azmuddin Abdullah. "Anticancer Compounds Derived from Marine Diatoms." Marine Drugs 18, no. 7 (July 9, 2020): 356. http://dx.doi.org/10.3390/md18070356.
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Cancer is the main cause of death worldwide, so the discovery of new and effective therapeutic agents must be urgently addressed. Diatoms are rich in minerals and secondary metabolites such as saturated and unsaturated fatty acids, esters, acyl lipids, sterols, proteins, and flavonoids. These bioactive compounds have been reported as potent anti-cancer, anti-oxidant and anti-bacterial agents. Diatoms are unicellular photosynthetic organisms, which are important in the biogeochemical circulation of silica, nitrogen, and carbon, attributable to their short growth-cycle and high yield. The biosilica of diatoms is potentially effective as a carrier for targeted drug delivery in cancer therapy due to its high surface area, nano-porosity, bio-compatibility, and bio-degradability. In vivo studies have shown no significant symptoms of tissue damage in animal models, suggesting the suitability of a diatoms-based system as a safe nanocarrier in nano-medicine applications. This review presents an overview of diatoms’ microalgae possessing anti-cancer activities and the potential role of the diatoms and biosilica in the delivery of anticancer drugs. Diatoms-based antibodies and vitamin B12 as drug carriers are also elaborated.
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Raven, John A. "Aquatic viruses: the emerging story." Journal of the Marine Biological Association of the United Kingdom 86, no. 3 (April 10, 2006): 449–51. http://dx.doi.org/10.1017/s0025315406013348.
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It is likely that all living organisms can be infected by one or more viruses. One of the latest higher taxa to be converted from ‘no characterized viruses’ to ‘well characterized viruses’ are the diatoms (Bacillariophyceae, Heterokontophyta) with the recent publication of three papers characterizing an ssRNA and a ssDNA virus from two genera (Chaetoceros and Rhizosolenia) of marine planktonic diatom (Nagasaki et al., 2004, 2005; Bettarel et al., 2005). It would have been strange if viruses had not been able to exploit the dominant, in terms of global primary production, photosynthetic organisms in the ocean (assimilating perhaps as much as 20 Pg inorganic C into organic C per year), despite the less than completely convincing arguments assembled by Raven & Waite (2004) as to possible anti-viral defences unique to diatoms.
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Sharma, Poonam, and Nivedita Sharma. "Industrial and Biotechnological Applications of Algae: A Review." Journal of Advances in Plant Biology 1, no. 1 (August 10, 2017): 1–25. http://dx.doi.org/10.14302/issn.2638-4469.japb-17-1534.
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Algae are a class of photosynthetic organisms found in both marine and freshwaters habitats. As these organisms have a short doubling time, they are considered among fastest growing creatures. They have different pathways to fix atmospheric carbon dioxide and to efficiently utilize the nutrients to convert it into biomass. In few years, a focus has been shifted towards these organisms due to their food and fuel production capability. In fuel industry algae biofuels have been emerged as a clean, nature friendly, cost effective solution to other fuels. Algae fuels are categorized into bio-ethanol, biogas, bio-hydrogen, biodiesel and bio-oil. Algae as a food have been explored for different applications as in production of single cell proteins, pigments, bioactive substances, pharmaceuticals and cosmetics. The present review has been prepared to throw a light on enormous applications of algae as food and fuel and also to provide some information about different commercially available algae products.
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Berdalet, Elisa, Lora E. Fleming, Richard Gowen, Keith Davidson, Philipp Hess, Lorraine C. Backer, Stephanie K. Moore, Porter Hoagland, and Henrik Enevoldsen. "Marine harmful algal blooms, human health and wellbeing: challenges and opportunities in the 21st century." Journal of the Marine Biological Association of the United Kingdom 96, no. 1 (November 20, 2015): 61–91. http://dx.doi.org/10.1017/s0025315415001733.
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Microalgal blooms are a natural part of the seasonal cycle of photosynthetic organisms in marine ecosystems. They are key components of the structure and dynamics of the oceans and thus sustain the benefits that humans obtain from these aquatic environments. However, some microalgal blooms can cause harm to humans and other organisms. These harmful algal blooms (HABs) have direct impacts on human health and negative influences on human wellbeing, mainly through their consequences to coastal ecosystem services (fisheries, tourism and recreation) and other marine organisms and environments. HABs are natural phenomena, but these events can be favoured by anthropogenic pressures in coastal areas. Global warming and associated changes in the oceans could affect HAB occurrences and toxicity as well, although forecasting the possible trends is still speculative and requires intensive multidisciplinary research. At the beginning of the 21st century, with expanding human populations, particularly in coastal and developing countries, mitigating HABs impacts on human health and wellbeing is becoming a more pressing public health need. The available tools to address this global challenge include maintaining intensive, multidisciplinary and collaborative scientific research, and strengthening the coordination with stakeholders, policymakers and the general public. Here we provide an overview of different aspects of the HABs phenomena, an important element of the intrinsic links between oceans and human health and wellbeing.
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Quigg, Antonietta, John Beardall, and Tom Wydrzynski. "Photoacclimation involves modulation of the photosynthetic oxygen-evolving reactions in Dunaliella tertiolecta and Phaeodactylum tricornutum." Functional Plant Biology 30, no. 3 (2003): 301. http://dx.doi.org/10.1071/fp02140.
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Net energy accumulation by marine microalgae at very low photon fluxes involves modulation of several attributes related to both the growth and photosynthetic physiology of these organisms. Here we studied flash-induced oscillatory patterns in oxygen evolution by previously dark-adapted cells of the green alga Dunaliella tertiolecta (Butcher) and the diatom Phaeodactylum tricornutum (Bohlin). The activity of the oxygen-evolving complex was found to be species-specific and influenced by photoacclimation. Results from measurements of oxygen flash yield obtained for these organisms grown under light-saturating conditions are directly comparable to those previously reported in the literature for other microalgae and higher plants. However, similar measurements on cells grown in low-light and/or light-starved conditions indicate an increased level of backward transitions (double misses) leading to the formation of super-reduced states (i.e. S–1 and S–2). Thus, in this communication, we present the first evidence that super-reduced states can be generated in vivo and speculate, on how they may be physiologically important.
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Uzair, Bushra, Sobia Tabassum, Madiha Rasheed, and Saima Firdous Rehman. "Exploring Marine Cyanobacteria for Lead Compounds of Pharmaceutical Importance." Scientific World Journal 2012 (2012): 1–10. http://dx.doi.org/10.1100/2012/179782.
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The Ocean, which is called the “mother of origin of life,” is also the source of structurally unique natural products that are mainly accumulated in living organisms. Cyanobacteria are photosynthetic prokaryotes used as food by humans. They are excellent source of vitamins and proteins vital for life. Several of these compounds show pharmacological activities and are helpful for the invention and discovery of bioactive compounds, primarily for deadly diseases like cancer, acquired immunodeficiency syndrome (AIDS), arthritis, and so forth, while other compounds have been developed as analgesics or to treat inflammation, and so forth. They produce a large variety of bioactive compounds, including substances with anticancer and antiviral activity, UV protectants, specific inhibitors of enzymes, and potent hepatotoxins and neurotoxins. Many cyanobacteria produce compounds with potent biological activities. This paper aims to showcase the structural diversity of marine cyanobacterial secondary metabolites with a comprehensive coverage of alkaloids and other applications of cyanobacteria.
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Doyle, Jason R., James N. Burnell, Dianne S. Haines, Lyndon E. Llewellyn, Cherie A. Motti, and Dianne M. Tapiolas. "A Rapid Screening Method to Detect Specific Inhibitors of Pyruvate Orthophosphate Dikinase as Leads for C₄ Plant-Selective Herbicides." Journal of Biomolecular Screening 10, no. 1 (February 2005): 67–75. http://dx.doi.org/10.1177/1087057104269978.
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Plants using the C4 photosynthetic pathway are highly represented among the world’s worst weeds, with only 4 C4 species being agriculturally productive (maize, sorghum, millet, and sugar cane). With the C4 acid cycle operating as a biochemical appendage of C3 photosynthesis, the additional enzymes involved in C4 photosynthesis represent an attractive target for the development of weed-specific herbicides. The rate-limiting enzyme of this metabolic pathway is pyruvate orthophosphate dikinase (PPDK). PPDK, coupled with phosphoenolpyruvate carboxylase and nicotinamide adenine dinucleotide-malate dehydrogenase, was used to develop a microplate-based assay to detect inhibitors of enzymes of the C4 acid cycle. The resulting assay had a Z′ factor of 0.61, making it a high-quality assay able to reliably identify active test samples. Organic extracts of 6679 marine macroscopic organisms were tested within the assay, and 343 were identified that inhibited the 3 enzyme-coupled reaction. A high confirmation rate was achieved, with 95% of these hit extracts proving active again upon retesting. Sequential addition of phosphoenolpyruvate and oxaloacetate to the assay facilitated identification of 83 extracts that specifically inhibited PPDK. ( Journal of Biomolecular Screening 2005:67-75)
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Puchkova, T. V., S. A. Khapchaeva, V. S. Zotov, A. A. Lukyanov, and A. E. Solovchenko. "Marine and freshwater microalgae as a sustainable source of cosmeceuticals." Marine Biological Journal 6, no. 1 (March 23, 2021): 67–81. http://dx.doi.org/10.21072/mbj.2021.06.1.06.
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A prominent feature of stress-tolerant microalgae is their versatile metabolism, allowing them to synthesize a broad spectrum of molecules. In microalgae, they increase stress resilience of these organisms. In human body, they exhibit anti-aging, anti-inflammatory, and sunscreen activities. This is not surprising, given that many of the stress-induced deleterious processes in human body and in photosynthetic cell are mediated by the same mechanisms: free-radical attacks and lipid peroxidation. It is also worth noting, that the photosynthetic machinery of microalgae is always at risk of oxidative damage since high redox potentials and reactive molecules are constantly generated during its functioning. These risks are kept at bay by efficient reactive oxygen species elimination systems including, inter alia, potent low-molecular antioxidants. Therefore, photosynthetic organisms are a rich source of bioactive substances with a great potential for curbing the negative effects of stresses, acting on human skin cells on a day-to-day basis. In many cases these compounds appear to be less toxic, less allergenic, and, in general, more “biocompatible” than most of their synthetic counterparts. The same algal metabolites are recognized as promising ingredients for innovative cosmetics and cosmeceutical formulations. Ever increasing efforts are being put into the search for new natural biologically active substances from microalgae. This trend is also fueled by the growing demand for natural raw materials for foods, nutraceuticals, pharmaceuticals, and cosmetology, associated with the global transition to a “greener” lifestyle. Although a dramatic diversity of cosmeceuticals was discovered in macrophyte algae, single-celled algae are on the same level or even surpass them in this regard. At the same time, a large-scale biotechnological production of microalgal biomass, enriched with the cosmeceutical compounds, is more technically feasible and economically viable than that of macrophyte biomass. The autotrophic cultivation of microalgae is generally simpler and often cheaper than that of heterotrophic microorganisms. Cultivation in bioreactors makes it possible to obtain more standardized raw biomass, quality of which is less dependent on seasonal factors. Microalgae biotechnology opens many possibilities to the “green” cosmeceutical production. However, a significant part of microalgae chemo- and biodiversity remains so far untapped. Consequently, bioprospecting and biochemical characterization of new algal species and strains, especially those isolated from habitats with harsh environmental conditions, is a major avenue for further research and development. Equally important is the development of approaches to cost-effective microalgae cultivation, as well as induction, extraction, and purification of cosmeceutical metabolites. World scientific community is rapidly accumulating extensive information on the chemistry and diverse effects of microalgae substances and metabolites; many substances of microalgal origin are extensively used in the cosmetic industry. However, the list of extracts and individual chemicals, isolated from them and thoroughly tested for safety and effectiveness, is not yet very large. Although excellent reviews of individual microalgal cosmeceutical groups exist, here we covered all the most important classes of such compounds of cosmeceutical relevance, linking the patterns of their composition and accumulation with the relevant aspects of microalgae biology.
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Kalasariya, Haresh S., Virendra Kumar Yadav, Krishna Kumar Yadav, Vineet Tirth, Ali Algahtani, Saiful Islam, Neha Gupta, and Byong-Hun Jeon. "Seaweed-Based Molecules and Their Potential Biological Activities: An Eco-Sustainable Cosmetics." Molecules 26, no. 17 (September 1, 2021): 5313. http://dx.doi.org/10.3390/molecules26175313.
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Amongst the countless marine organisms, seaweeds are considered as one of the richest sources of biologically active ingredients having powerful biological activities. Seaweeds or marine macroalgae are macroscopic multicellular eukaryotic photosynthetic organisms and have the potential to produce a large number of valuable compounds, such as proteins, carbohydrates, fatty acids, amino acids, phenolic compounds, pigments, etc. Since it is a prominent source of bioactive constituents, it finds diversified industrial applications viz food and dairy, pharmaceuticals, medicinal, cosmeceutical, nutraceutical, etc. Moreover, seaweed-based cosmetic products are risen up in their demands by the consumers, as they see them as a promising alternative to synthetic cosmetics. Normally it contains purified biologically active compounds or extracts with several compounds. Several seaweed ingredients that are useful in cosmeceuticals are known to be effective alternatives with significant benefits. Many seaweeds’ species demonstrated skin beneficial activities, such as antioxidant, anti-melanogenesis, antiaging, photoprotection, anti-wrinkle, moisturizer, antioxidant, anti-inflammatory, anticancer and antioxidant properties, as well as certain antimicrobial activities, such as antibacterial, antifungal and antiviral activities. This review presents applications of bioactive molecules derived from marine algae as a potential substitute for its current applications in the cosmetic industry. The biological activities of carbohydrates, proteins, phenolic compounds and pigments are discussed as safe sources of ingredients for the consumer and cosmetic industry.
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Plummer, Abigail, Roberto Benzi, David R. Nelson, and Federico Toschi. "Fixation probabilities in weakly compressible fluid flows." Proceedings of the National Academy of Sciences 116, no. 2 (December 26, 2018): 373–78. http://dx.doi.org/10.1073/pnas.1812829116.
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Competition between biological species in marine environments is affected by the motion of the surrounding fluid. An effective 2D compressibility can arise, for example, from the convergence and divergence of water masses at the depth at which passively traveling photosynthetic organisms are restricted to live. In this report, we seek to quantitatively study genetics under flow. To this end, we couple an off-lattice agent-based simulation of two populations in 1D to a weakly compressible velocity field—first a sine wave and then a shell model of turbulence. We find for both cases that even in a regime where the overall population structure is approximately unaltered, the flow can significantly diminish the effect of a selective advantage on fixation probabilities. We understand this effect in terms of the enhanced survival of organisms born at sources in the flow and the influence of Fisher genetic waves.
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Kamennaya, Nina A., and Anton F. Post. "Characterization of Cyanate Metabolism in MarineSynechococcusandProchlorococcusspp." Applied and Environmental Microbiology 77, no. 1 (November 5, 2010): 291–301. http://dx.doi.org/10.1128/aem.01272-10.
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ABSTRACTCyanobacteria of the generaSynechococcusandProchlorococcusare the most abundant photosynthetic organisms on earth, occupying a key position at the base of marine food webs. ThecynSgene that encodes cyanase was identified among bacterial, fungal, and plant sequences in public databases, and the gene was particularly prevalent among cyanobacteria, including numerousProchlorococcusandSynechococcusstrains. Phylogenetic analysis ofcynSsequences retrieved from the Global Ocean Survey database identified >60% as belonging to unicellular marine cyanobacteria, suggesting an important role for cyanase in their nitrogen metabolism. We demonstrate here that marine cyanobacteria have a functionally active cyanase, the transcriptional regulation of which varies among strains and reflects the genomic context ofcynS. InProchlorococcussp. strain MED4,cynSwas presumably transcribed as part of thecynABDSoperon, implying cyanase involvement in cyanate utilization. InSynechococcussp. strain WH8102, expression was not related to nitrogen stress responses and here cyanase presumably serves in the detoxification of cyanate resulting from intracellular urea and/or carbamoyl phosphate decomposition. Lastly, we report on a cyanase activity encoded bycynH, a novel gene found in marine cyanobacteria only. The presence of dual cyanase genes in the genomes of seven marineSynechococcusstrains and their respective roles in nitrogen metabolism remain to be clarified.
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Sun, Dong, Ning He, Qi Chen, and Shunshan Duan. "Effects of Lanthanum on the Photosystem II Energy Fluxes and Antioxidant System of Chlorella Vulgaris and Phaeodactylum Tricornutum." International Journal of Environmental Research and Public Health 16, no. 12 (June 25, 2019): 2242. http://dx.doi.org/10.3390/ijerph16122242.
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The rare earth elements are widely used in agricultural and light industry development. They promote the growth of crop seedlings, enhance root development and change the metal properties. Due to the large amount of rare earth minerals mined in China, rare earth elements have been detected in both coastal and estuary areas. They cause pollution and threaten the health of aquatic organisms and human beings. This study investigates the effects of lanthanum on two marine bait algae, and analyzes the changes in the photosynthetic and antioxidant systems of the two algae. The results show that rare earth elements have significant inhibitory effects upon the two algae. The OJIP kinetic curve value decreases with an increasing concentration of La(NO3)3 ·6H2O. The parameters of the fluorescence value were analyzed. The ABS/RC increases and the DI0/RC decreases during the first 24 h after exposure. The effects on the photosynthetic and antioxidant systems at low concentrations (both EC10 and EC20) show that the TR0/ABS increases, and the ET0/RC, ABS/RC, and DI0/RC has a decreasing trend after 30 min. However, after 24 h, normal levels were restored. In addition, the study finds that the TR0/ABS increases after 24 h, leading to an increase in reactive oxygen species. The antioxidant system analysis also confirms the increase in the activities of antioxidant enzymes, such as SOD and GSH. The experiment is expected to support the marine pollution of rare earths and the theoretical data of the impact on marine primary producers.
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Taylor, Vivien F., Brian P. Jackson, Matthew R. Siegfried, Jana Navratilova, Kevin A. Francesconi, Julie Kirshtein, and Mary Voytek. "Arsenic speciation in food chains from mid-Atlantic hydrothermal vents." Environmental Chemistry 9, no. 2 (2012): 130. http://dx.doi.org/10.1071/en11134.
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Environmental contextArsenic occurs in marine organisms at high levels and in many chemical forms. A common explanation of this phenomenon is that algae play the central role in accumulating arsenic by producing arsenic-containing sugars that are then converted into simpler organic arsenic compounds found in fish and other marine animals. We show that animals in deep-sea vent ecosystems, which are uninhabited by algae, contain the same organic arsenic compounds as do pelagic animals, indicating that algae are not the only source of these compounds. AbstractArsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge hydrothermal vents. The shrimp species, Rimicaris exoculata, the vent chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (δ13C and δ15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the vent chimneys covered with microbial mat, which is a presumed food source for many vent organisms, contained high levels of total As, but organic species were not detectable. The formation of arsenosugars in pelagic environments is typically attributed to marine algae, and the pathway to arsenobetaine is still unknown. The occurrence of arsenosugars and arsenobetaine in these deep sea organisms, where primary production is chemolithoautotrophic and stable isotope analyses indicate food sources are of vent origin, suggests that organic arsenicals can occur in a foodweb without algae or other photosynthetic life.
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Day, John G., and Michael Francis Turner. "Live protist curation at the Scottish Association for Marine Science, 1884–2017." Archives of Natural History 45, no. 2 (October 2018): 267–82. http://dx.doi.org/10.3366/anh.2018.0519.
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Understanding and exploiting marine microbial biodiversity is a huge task. Integral to this is the capacity to identify and maintain exemplar taxa ex situ, so that they may be studied or utilized. This paper focuses on protists, primarily photosynthetic protists, including microalgae and macroalgae, as well as the prokaryotic cyanobacteria. It draws together the strands of activities undertaken by scientists in the fields of taxonomy, systematics and algal cultivation associated with the Scottish Association for Marine Science at Oban and its predecessors: the Scottish Marine Station, originally located on a converted lighter, The Ark, in a flooded quarry in Granton near Edinburgh, then subsequently at Millport on the Clyde; the Marine Biological Association – West Scotland at Millport; and the Scottish Marine Biological Association, founded in 1914, initially at Millport and subsequently at Dunstaffnage, Oban. The work undertaken is interwoven with the historical status and development of protistan curation over the past 130 years. The paper also examines the inter-linkages of the organization with the development of cultivation techniques and the provision of biological resources from 1914 by the then newly established Scottish Marine Biological Association to the Culture Collection of Algae and Protozoa today. Finally, we briefly outline current developments that will influence the curation and scientific exploitation of these diverse organisms in the future.
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Needham, David M., Susumu Yoshizawa, Toshiaki Hosaka, Camille Poirier, Chang Jae Choi, Elisabeth Hehenberger, Nicholas A. T. Irwin, et al. "A distinct lineage of giant viruses brings a rhodopsin photosystem to unicellular marine predators." Proceedings of the National Academy of Sciences 116, no. 41 (September 23, 2019): 20574–83. http://dx.doi.org/10.1073/pnas.1907517116.
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Giant viruses are remarkable for their large genomes, often rivaling those of small bacteria, and for having genes thought exclusive to cellular life. Most isolated to date infect nonmarine protists, leaving their strategies and prevalence in marine environments largely unknown. Using eukaryotic single-cell metagenomics in the Pacific, we discovered a Mimiviridae lineage of giant viruses, which infects choanoflagellates, widespread protistan predators related to metazoans. The ChoanoVirus genomes are the largest yet from pelagic ecosystems, with 442 of 862 predicted proteins lacking known homologs. They are enriched in enzymes for modifying organic compounds, including degradation of chitin, an abundant polysaccharide in oceans, and they encode 3 divergent type-1 rhodopsins (VirR) with distinct evolutionary histories from those that capture sunlight in cellular organisms. One (VirRDTS) is similar to the only other putative rhodopsin from a virus (PgV) with a known host (a marine alga). Unlike the algal virus, ChoanoViruses encode the entire pigment biosynthesis pathway and cleavage enzyme for producing the required chromophore, retinal. We demonstrate that the rhodopsin shared by ChoanoViruses and PgV binds retinal and pumps protons. Moreover, our 1.65-Å resolved VirRDTS crystal structure and mutational analyses exposed differences from previously characterized type-1 rhodopsins, all of which come from cellular organisms. Multiple VirR types are present in metagenomes from across surface oceans, where they are correlated with and nearly as abundant as a canonical marker gene from Mimiviridae. Our findings indicate that light-dependent energy transfer systems are likely common components of giant viruses of photosynthetic and phagotrophic unicellular marine eukaryotes.
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Dalheim, Lars, Jon Brage Svenning, and Ragnar Ludvig Olsen. "In vitro intestinal digestion of lipids from the marine diatom Porosira glacialis compared to commercial LC n-3 PUFA products." PLOS ONE 16, no. 6 (June 9, 2021): e0252125. http://dx.doi.org/10.1371/journal.pone.0252125.
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Marine sources of long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) are in high demand for use in health supplements. Mass cultivated marine microalgae is a promising and sustainable source of LC n-3 PUFA, which relieves pressure on natural fish stocks. The lipid class profile from cultivated photosynthetic algae differ from the marine organisms currently used for the production of LC n-3 PUFA. The objective of this study was to compare in vitro intestinal digestion of oil extracted from the cold-adapted marine diatom Porosira glacialis with commercially available LC n-3 PUFA supplements; cod liver oil, krill oil, ethyl ester concentrate, and oil from the copepod Calanus finmarchicus (Calanus® oil). The changes in the free fatty acids and neutral and polar lipids during the enzymatic hydrolysis were characterized by liquid and gas chromatography. In Calanus® oil and the Ethyl ester concentrate, the free fatty acids increased very little (4.0 and 4.6%, respectively) during digestion. In comparison, free fatty acids in Krill oil and P. glacialis oil increased by 14.7 and 17.0%, respectively. Cod liver oil had the highest increase (28.2%) in free fatty acids during the digestion. Monounsaturated and saturated fatty acids were more easily released than polyunsaturated fatty acids in all five oils.
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van der Heijden, L. H., and N. A. Kamenos. "Reviews and syntheses: Calculating the global contribution of coralline algae to total carbon burial." Biogeosciences 12, no. 21 (November 10, 2015): 6429–41. http://dx.doi.org/10.5194/bg-12-6429-2015.
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Abstract. The ongoing increase in anthropogenic carbon dioxide (CO2) emissions is changing the global marine environment and is causing warming and acidification of the oceans. Reduction of CO2 to a sustainable level is required to avoid further marine change. Many studies investigate the potential of marine carbon sinks (e.g. seagrass) to mitigate anthropogenic emissions, however, information on storage by coralline algae and the beds they create is scant. Calcifying photosynthetic organisms, including coralline algae, can act as a CO2 sink via photosynthesis and CaCO3 dissolution and act as a CO2 source during respiration and CaCO3 production on short-term timescales. Long-term carbon storage potential might come from the accumulation of coralline algae deposits over geological timescales. Here, the carbon storage potential of coralline algae is assessed using meta-analysis of their global organic and inorganic carbon production and the processes involved in this metabolism. Net organic and inorganic production were estimated at 330 g C m−2 yr−1 and 900 g CaCO3 m−2 yr−1 respectively giving global organic/inorganic C production of 0.7/1.8 × 109 t C yr−1. Calcium carbonate production by free-living/crustose coralline algae (CCA) corresponded to a sediment accretion of 70/450 mm kyr−1. Using this potential carbon storage for coralline algae, the global production of free-living algae/CCA was 0.4/1.2 × 109 t C yr−1 suggesting a total potential carbon sink of 1.6 × 109 tonnes per year. Coralline algae therefore have production rates similar to mangroves, salt marshes and seagrasses representing an as yet unquantified but significant carbon store, however, further empirical investigations are needed to determine the dynamics and stability of that store.
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van der Heijden, L. H., and N. A. Kamenos. "Calculating the global contribution of coralline algae to carbon burial." Biogeosciences Discussions 12, no. 10 (May 26, 2015): 7845–77. http://dx.doi.org/10.5194/bgd-12-7845-2015.
Full textAbstract:
Abstract. The ongoing increase in anthropogenic carbon dioxide (CO2) emissions is changing the global marine environment and is causing warming and acidification of the oceans. Reduction of CO2 to a sustainable level is required to avoid further marine change. Many studies investigate the potential of marine carbon sinks (e.g. seagrass) to mitigate anthropogenic emissions, however, information on storage by coralline algae and the beds they create is scant. Calcifying photosynthetic organisms, including coralline algae, can act as a CO2 sink via photosynthesis and CaCO3 dissolution and act as a CO2 source during respiration and CaCO3 production on short-term time scales. Long-term carbon storage potential might come from the accumulation of coralline algae deposits over geological time scales. Here, the carbon storage potential of coralline algae is assessed using meta-analysis of their global organic and inorganic carbon production and the processes involved in this metabolism. Organic and inorganic production were estimated at 330 g C m−2 yr−1 and 880 g CaCO3 m−2 yr−1 respectively giving global organic/inorganic C production of 0.7/1.8 × 109 t C yr−1. Calcium carbonate production by free-living/crustose coralline algae (CCA) corresponded to a sediment accretion of 70/450 mm kyr−1. Using this potential carbon storage by coralline algae, the global production of free-living algae/CCA was 0.4/1.2 × 109 t C yr−1 suggesting a total potential carbon sink of 1.6 × 109 t C yr−1. Coralline algae therefore have production rates similar to mangroves, saltmarshes and seagrasses representing an as yet unquantified but significant carbon store, however, further empirical investigations are needed to determine the dynamics and stability of that store.
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Benites, L. Felipe, Nicole Poulton, Karine Labadie, Michael E. Sieracki, Nigel Grimsley, and Gwenael Piganeau. "Single cell ecogenomics reveals mating types of individual cells and ssDNA viral infections in the smallest photosynthetic eukaryotes." Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1786 (October 7, 2019): 20190089. http://dx.doi.org/10.1098/rstb.2019.0089.
Full textAbstract:
Planktonic photosynthetic organisms of the class Mamiellophyceae include the smallest eukaryotes (less than 2 µm), are globally distributed and form the basis of coastal marine ecosystems. Eight complete fully annotated 13–22 Mb genomes from three genera, Ostreococcus , Bathycoccus and Micromonas , are available from previously isolated clonal cultured strains and provide an ideal resource to explore the scope and challenges of analysing single cell amplified genomes (SAGs) isolated from a natural environment. We assembled data from 12 SAGs sampled during the Tara Oceans expedition to gain biological insights about their in situ ecology, which might be lost by isolation and strain culture. Although the assembled nuclear genomes were incomplete, they were large enough to infer the mating types of four Ostreococcus SAGs. The systematic occurrence of sequences from the mitochondria and chloroplast, representing less than 3% of the total cell's DNA, intimates that SAGs provide suitable substrates for detection of non-target sequences, such as those of virions. Analysis of the non-Mamiellophyceae assemblies, following filtering out cross-contaminations during the sequencing process, revealed two novel 1.6 and 1.8 kb circular DNA viruses, and the presence of specific Bacterial and Oomycete sequences suggests that these organisms might co-occur with the Mamiellales. This article is part of a discussion meeting issue ‘Single cell ecology’.
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TALEBI, Ahmad Farhad, Meisam TABATABAEI, Seyed Kaveh MOHTASHAMI, Masoud TOHIDFAR, and Foad MORADI. "Comparative Salt Stress Study on Intracellular Ion Concentration in Marine and Salt-adapted Freshwater Strains of Microalgae." Notulae Scientia Biologicae 5, no. 3 (August 1, 2013): 309–15. http://dx.doi.org/10.15835/nsb539114.
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Salinity imposes significant stresses in various living organisms including microalgae. High extracellular concentration of Na+ directly influences ionic balance inside the cell and subsequently the cellular activities. In the present study, the effect of such stress on growth and intracellular ions concentration (IIC) of Dunaliella salina and Chlorella Spp. was investigated. IIC was analyzed using Ion chromatography technique. D. salina showed the highest degree of resistance to increase in salinity as little changes occurred both in IIC and in growth parameters. D. salina could maintain the balance of K+ inside the cell and eject the excess Na+ even at NaCl concentrations above 1M. Moreover, D. salina accumulated β-carotene in order to protect its photosynthetic apparatus. Among Chlorella species, C. vulgaris showed signs of adaptation to high content of salinity, though it is a fresh water species by nature. Moreover, the response shown by C. vulgaris to rise in salinity was even stronger than that of C. salina, which is presumably a salt-water resistant species. In fact, C. vulgaris could maintain intracellular K+ better than C. salina in response to increasing salinity, and as a result, it could survive at NaCl concentrations as high as 0.75 M. Marine strains such as D. salina well cope with the fluctuations in salinity through the existing adaptation mechanisms i.e. maintaining the K+/N+ balance inside the cell, K+ accumulation and Na+ ejection, accumulation of photosynthetic pigments like β-carotene.