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Adaptation to Hydrogen Sulfide of Oxygenic and Anoxygenic Photosynthesis among Cyanobacteria.

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TLDR
In this paper, four different types of adaptation to sulfide among cyanobacteria are described based on the differential toxicity of photosystems I and II and the capacity for the induction of anoxygenic photosynthesis.
Abstract
Four different types of adaptation to sulfide among cyanobacteria are described based on the differential toxicity to sulfide of photosystems I and II and the capacity for the induction of anoxygenic photosynthesis. Most cyanobacteria are highly sensitive to sulfide toxicity, and brief exposures to low concentrations cause complete and irreversible cessation of CO2 photoassimilation. Resistance of photosystem II to sulfide toxicity, allowing for oxygenic photosynthesis under sulfide, is found in cyanobacteria exposed to low H2S concentrations in various hot springs. When H2S levels exceed 200 μM another type of adaptation involving partial induction of anoxygenic photosynthesis, operating in concert with partially inhibited oxygenic photosynthesis, is found in cyanobacterial strains isolated from both hot springs and hypersaline cyanobacterial mats. The fourth type of adaptation to sulfide is found at H2S concentrations higher than 1 mM and involves a complete replacement of oxygenic photosynthesis by an effective sulfide-dependent, photosystem II-independent anoxygenic photosynthesis. The ecophysiology of the various sulfide-adapted cyanobacteria may point to their uniqueness within the division of cyanobacteria.

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Journal ArticleDOI

Oxygenic photosynthesis as a protection mechanism for cyanobacteria against iron-encrustation in environments with high Fe2+ concentrations

TL;DR: It is proposed that, due to limited mass transfer, high photosynthetic activity in Fe2-rich environments forms a protective zone where Fe2+ precipitates abiotically at a non-lethal distance from the cyanobacteria.
Journal ArticleDOI

Sulfur Assimilation in Photosynthetic Organisms: Molecular Functions and Regulations of Transporters and Assimilatory Enzymes

TL;DR: This review provides up-to-date knowledge in functions and regulations of sulfur assimilation in plants and algae, focusing on sulfate transport systems and metabolic pathways for sulfate reduction and synthesis of downstream metabolites with diverse biological functions.
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Ferrous iron oxidation by anoxygenic phototrophic bacteria

TL;DR: In this paper, the authors describe a bacteria that can oxidize colourless Fe(u) to brown Fe(in) and reduce CO2 to cell material, implying that oxygen-independent biological iron oxidation was possible before the evolution of oxygenic photosynthesis.
Journal ArticleDOI

Exocellular polysaccharides from cyanobacteria and their possible applications

TL;DR: An overview of the current knowledge on both RPS-producing cyanobacterial strains (including the possible roles of the exopolysaccharides) and chemical characteristics of the cyanob bacterial RPSs is given, with particular emphasis on RPS properties and possible industrial applications.
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Spatial patterns and links between microbial community composition and function in cyanobacterial mats

TL;DR: It is demonstrated that the spatial variability in the photosynthetic capacity and light acclimation of benthic phototrophic microbial communities is at least as large on a sub-millimeter scale as it is on a global scale, and suggests that this pattern of variability scaling is similar for the microbial community composition.
References
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Journal ArticleDOI

Generic assignments, strain histories, and properties of pure cultures of cyanobacteria

TL;DR: Revisions are designed to permit the generic identification of cultures, often difficult through use of the field-based system of phycological classification, and are both constant and readily determinable in cultured material.
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Spectrophotometric determination of hydrogen sulfide in natural waters1

TL;DR: Winkler and Carpenter as mentioned in this paper proposed a modification of the Winkler method for the detection of dissolved oxygen in seawater, which has been shown to be more accurate than the original method.
BookDOI

Thermophilic microorganisms and life at high temperatures

TL;DR: In this article, the authors studied the effect of temperature on physical and chemical parameters of the organisms in the Hot Springs of Yellowstone National Park in the US and found that there is an upper temperature limit for life.
Journal ArticleDOI

Microelectrode studies of the photosynthesis and O2, H2S, and pH profiles of a microbial mat1

TL;DR: The profiles of O, H,S, and pH within a microbial mat of the hypcrsaline pond Solar Lake, Sinai, were measured by 2-208pm-thick microelectrodes during diurnal and artificial light cycles as mentioned in this paper.
Journal ArticleDOI

Photosynthesis and structure of benthic microbial mats: Microelectrode and SEM studies of four cyanobacterial communities1

TL;DR: In this article, the microzonation of photosynthetic organisms in four cyanobacterial mats of Solar Lake, Sinai, was studied by light and scanning electron microscopy, which allowed a spatial resolution of 100 µm.