Anoxygenic Phototrophic Bacteria from Extreme Environments

Imhoff, Johannes F.

doi:10.1007/978-3-319-46261-5_13

Cited by 17 publications

(10 citation statements)

References 166 publications

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“…Therefore, bacteria that have no shortage in energy and nitrogen supply, such as phototrophic bacteria, which use sunlight as an energy source and are capable of fixing dinitrogen, are likely to be the first and also to be the most successful in conquering highly saline habitats. In fact, mass developments of phototrophic bacteria regularly occur in salt and soda lakes, as well as in coastal lagoons, and cause colored blooms [ 1 , 7 , 53 , 54 , 55 ].…”

Section: Resultsmentioning

confidence: 99%

Osmotic Adaptation and Compatible Solute Biosynthesis of Phototrophic Bacteria as Revealed from Genome Analyses

et al. 2020

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Osmotic adaptation and accumulation of compatible solutes is a key process for life at high osmotic pressure and elevated salt concentrations. Most important solutes that can protect cell structures and metabolic processes at high salt concentrations are glycine betaine and ectoine. The genome analysis of more than 130 phototrophic bacteria shows that biosynthesis of glycine betaine is common among marine and halophilic phototrophic Proteobacteria and their chemotrophic relatives, as well as in representatives of Pirellulaceae and Actinobacteria, but are also found in halophilic Cyanobacteria and Chloroherpeton thalassium. This ability correlates well with the successful toleration of extreme salt concentrations. Freshwater bacteria in general lack the possibilities to synthesize and often also to take up these compounds. The biosynthesis of ectoine is found in the phylogenetic lines of phototrophic Alpha- and Gammaproteobacteria, most prominent in the Halorhodospira species and a number of Rhodobacteraceae. It is also common among Streptomycetes and Bacilli. The phylogeny of glycine-sarcosine methyltransferase (GMT) and diaminobutyrate-pyruvate aminotransferase (EctB) sequences correlate well with otherwise established phylogenetic groups. Most significantly, GMT sequences of cyanobacteria form two major phylogenetic branches and the branch of Halorhodospira species is distinct from all other Ectothiorhodospiraceae. A variety of transport systems for osmolytes are present in the studied bacteria.

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Section: Resultsmentioning

confidence: 99%

Osmotic Adaptation and Compatible Solute Biosynthesis of Phototrophic Bacteria as Revealed from Genome Analyses

et al. 2020

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“…HH T was isolated from the shore of the alkaline (pH 10) Lake El Hamra (Figure 2A), located in the Wadi El Natroun region of northern Egypt [21]. In the past, the saline lakes of the Wadi El Natroun have also been a fertile source of alkaliphilic purple bacteria, yielding many extremely alkaliphilic (and in some cases also extremely halophilic) species, including in particular, new species of the genus Halorhodospira [23][24][25]. However, Hrs.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Complete Genome of the Alkaliphilic and Phototrophic Firmicute Heliorestis convoluta Strain HHT

et al. 2020

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Despite significant interest and past work to elucidate the phylogeny and photochemistry of species of the Heliobacteriaceae, genomic analyses of heliobacteria to date have been limited to just one published genome, that of the thermophilic species Heliobacterium (Hbt.) modesticaldum str. Ice1T. Here we present an analysis of the complete genome of a second heliobacterium, Heliorestis (Hrs.) convoluta str. HHT, an alkaliphilic, mesophilic, and morphologically distinct heliobacterium isolated from an Egyptian soda lake. The genome of Hrs. convoluta is a single circular chromosome of 3.22 Mb with a GC content of 43.1% and 3263 protein-encoding genes. In addition to culture-based observations and insights gleaned from the Hbt. modesticaldum genome, an analysis of enzyme-encoding genes from key metabolic pathways supports an obligately photoheterotrophic lifestyle for Hrs. convoluta. A complete set of genes encoding enzymes for propionate and butyrate catabolism and the absence of a gene encoding lactate dehydrogenase distinguishes the carbon metabolism of Hrs. convoluta from its close relatives. Comparative analyses of key proteins in Hrs. convoluta, including cytochrome c553 and the Fo alpha subunit of ATP synthase, with those of related species reveal variations in specific amino acid residues that likely contribute to the success of Hrs. convoluta in its highly alkaline environment.

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“…Purple sulfur bacteria (PSB; Family Chromatiaceae) are a large group of anoxygenic phototrophic Gammaproteobacteria that inhabit illuminated anoxic and sulfidic aquatic environments including the hypolimnion of lakes and ponds, estuaries, and intertidal and subtidal ocean waters, sulfide-containing springs, and a host of extreme environments (Imhoff, 2017;Madigan, 1988Madigan, , 2003Madigan & Jung, 2009;Pfennig, 1967Pfennig, , 1989. Extensive blooms of PSB are typically found in habitats where sulfide produced by sulfate-reducing bacteria or emitted from geochemical sources supplies the electron donor for anoxygenic photosynthesis.…”

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Calcium and the ecology of photosynthesis in purple sulfur bacteria

Madigan,

Sattley,

Kimura

et al. 2024

Environmental Microbiology

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The ecological success of purple sulfur bacteria (PSB) is linked to their ability to collect near‐infrared solar energy by membrane‐integrated, pigment–protein photocomplexes. These include a Core complex containing both light‐harvesting 1 (LH1) and reaction centre (RC) components (called the LH1–RC photocomplex) present in all PSB and a peripheral light‐harvesting complex present in most but not all PSB. In research to explain the unusual absorption properties of the thermophilic purple sulfur bacterium Thermochromatium tepidum, Ca2+ was discovered bound to LH1 polypeptides in its LH1–RC; further work showed that calcium controls both the thermostability and unusual spectrum of the Core complex. Since then, Ca2+ has been found in the LH1–RC photocomplexes of several other PSB, including mesophilic species, but not in the LH1–RC of purple non‐sulfur bacteria. Here we focus on four species of PSB—two thermophilic and two mesophilic—and describe how Ca2+ is integrated into and affects their photosynthetic machinery and why this previously overlooked divalent metal is a key nutrient for their ecological success.

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Anoxygenic Phototrophic Bacteria from Extreme Environments

Cited by 17 publications

References 166 publications

Osmotic Adaptation and Compatible Solute Biosynthesis of Phototrophic Bacteria as Revealed from Genome Analyses

Osmotic Adaptation and Compatible Solute Biosynthesis of Phototrophic Bacteria as Revealed from Genome Analyses

Analysis of the Complete Genome of the Alkaliphilic and Phototrophic Firmicute Heliorestis convoluta Strain HHT

Calcium and the ecology of photosynthesis in purple sulfur bacteria

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