The Family Desulfobacteraceae

Kuever, Jan

doi:10.1007/978-3-642-39044-9_266

Cited by 69 publications

(53 citation statements)

References 47 publications

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“…The Dbact bin also contained and expressed genes for a CO dehydrogenase ( coxMS ) that typically couples the oxidation of CO to the reduction of oxygen or nitrate in aerobes or facultative anaerobes (King & Weber, ). The Desulfobacteraceae and Desulfobulbaceae are both typically strict anaerobes (Kuever, ,b). However, homologs of aerobic CO dehydrogenases have been identified in other Desulfobacteraceae and Desulfobulbaceae genomes (e.g., Desulfotignum phosphitoxidans WP_006968093 and Desulfotalea psychrophila WP_011189774).…”

Section: Resultsmentioning

confidence: 99%

“…As with other anaerobic ciliates and their symbionts, it was hypothesized that the brown ciliate's fermentative metabolism is coupled to symbiont metabolism via the transfer of H 2 and/or small organic molecules. Desulfobacteraceae and Desulfobulbaceae are sulphur‐reducing families that couple the oxidization of H 2 or organic compounds (Kuever, ,b) to the reduction of the inorganic electron acceptors sulphate, sulphite, thiosulfate, and/or, in the case of Desulfobulbaceae, sometimes nitrate (Kuever, a). Here, we used metagenomic and metatranscriptomic sequencing of individuals or small pools of ciliates to explore metabolic coupling between host and symbionts, as well as to assess other aspects of symbiont physiology, like cell division.…”

Section: Introductionmentioning

confidence: 99%

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Insights into the metabolic functioning of a multipartner ciliate symbiosis from oxygen‐depleted sediments

et al. 2018

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Symbioses between anaerobic or microaerophilic protists and prokaryotes are common in anoxic and oxygen-depleted habitats ranging from marine sediments to gastrointestinal tracts. Nevertheless, little is known about the mechanisms of metabolic interaction between partners. In these putatively syntrophic associations, consumption of fermentative end products (e.g., hydrogen) by the prokaryotic symbionts is thought to facilitate protistan anaerobic metabolism. Here, we employed metagenomic and metatranscriptomic sequencing of a microaerophilic or anaerobic karyorelictid ciliate and its prokaryotic symbionts from oxygen-depleted Santa Barbara Basin (CA, USA) sediments to assess metabolic coupling within this consortium. This sequencing confirmed the predominance of deltaproteobacterial symbionts from the Families Desulfobacteraceae and Desulfobulbaceae and suggested active symbiont reduction of host-provided sulphate, transfer of small organic molecules from host to symbionts and hydrogen cycling among the symbionts. In addition, patterns of gene expression indicated active cell division by the symbionts, their growth via autotrophic processes and nitrogen exchange with the ciliate host. Altogether, this research underscores the importance of symbiont metabolism to host fermentative metabolism and, thus, likely its success in anoxic and low-oxygen habitats, but also suggests ciliate-associated prokaryotes play a role in important biogeochemical processes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Insights into the metabolic functioning of a multipartner ciliate symbiosis from oxygen‐depleted sediments

et al. 2018

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“…Representatives of these families are chemoorganoheterotrophs that were previously isolated from freshwater [105], as well as soil [106] ecosystems. A highly diverse community of Delta-Proteobacteria was identified in September PA samples: Within the thermocline datasets, the majority of Delta-Proteobacteria sequences belonged to the order Myxococcales, fruiting gliding bacteria that thrive on water-insoluble organic matter, often dead or alive cells, when nutrients are plentiful [107], and the uncultured order MIZ46 previously found to be active during the generation of anoxia in freshwater systems [108], while in the deeper hypolimnion Delta-Proteobacteria sequences were dominated by sulfate reducers, presumably using sulfated compounds released from cell walls as electron acceptor (Desulfobacula and Desulfobacteraceae [109, 110]). The PA community of both thermocline and hypolimnion layers also contained significant levels of the predatory Bdellovibrio , a reflection of the increase in number of microbial preys [111].…”

Section: Resultsmentioning

confidence: 99%

Spatiotemporal analysis of microbial community dynamics during seasonal stratification events in a freshwater lake (Grand Lake, OK, USA)

Morrison

Baker

Zamor³

et al. 2017

PLoS ONE

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Many freshwater lakes undergo seasonal stratification, where the formation of phototrophic blooms in the epilimnion and subsequent sedimentation induces hypoxia/anoxia in the thermocline and hypolimnion. This autochthonously produced biomass represents a major seasonal organic input that impacts the entire ecosystem. While the limnological aspects of this process are fairly well documented, relatively little is known regarding the microbial community response to such events, especially in the deeper anoxic layers of the water column. Here, we conducted a spatiotemporal survey of the particle-associated and free-living microbial communities in a warm monomictic freshwater reservoir (Grand Lake O’ the Cherokees) in northeastern Oklahoma, USA. Pre-stratification samples (March) harbored a homogeneous community throughout the oxygenated water column dominated by typical oligotrophic aquatic lineages (acl clade within Actinobacteria, and Flavobacterium within the Bacteroidetes). The onset of phototrophic blooming in June induced the progression of this baseline community into two distinct trajectories. Within the oxic epilimnion, samples were characterized by the propagation of phototrophic (Prochlorococcus), and heterotrophic (Planctomycetes, Verrucomicrobia, and Beta-Proteobacteria) lineages. Within the oxygen-deficient thermocline and hypolimnion, the sedimentation of surface biomass induced the development of a highly diverse community, with the enrichment of Chloroflexi, “Latescibacteria”, Armatimonadetes, and Delta-Proteobacteria in the particle-associated fraction, and Gemmatimonadetes and “Omnitrophica” in the free-living fraction. Our work documents the development of multiple spatially and temporally distinct niches during lake stratification, and supports the enrichment of multiple yet-uncultured and poorly characterized lineages in the lake’s deeper oxygen-deficient layers, an ecologically relevant microbial niche that is often overlooked in lakes diversity surveys.

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“…‘ Ca . Adiutrix intracellularis’ shares only very low sequence similarity (86.1–86.6%) with the 16S rRNA genes of its closest cultured relatives, namely Desulfatiglans ( Desulfobacterium ) anilini , Desulfoarculus baarsii and Desulfomonile tiedjei , which are each considered to represent a different order of Deltaproteobacteria (Kuever, ), underlining the deep‐branching nature of the novel clade.…”

Section: Resultsmentioning

confidence: 99%

‘Candidatus Adiutrix intracellularis’, an endosymbiont of termite gut flagellates, is the first representative of a deep‐branching clade of Deltaproteobacteria and a putative homoacetogen

Ikeda-Ohtsubo

Strassert

Köhler

et al. 2016

Environmental Microbiology

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Termite gut flagellates are typically colonized by specific bacterial symbionts. Here we describe the phylogeny, ultrastructure and subcellular location of 'Candidatus Adiutrix intracellularis', an intracellular symbiont of Trichonympha collaris in the termite Zootermopsis nevadensis. It represents a novel, deep-branching clade of uncultured Deltaproteobacteria widely distributed in intestinal tracts of termites and cockroaches. Fluorescence in situ hybridization and transmission electron microscopy localized the endosymbiont near hydrogenosomes in the posterior part and near the ectosymbiont 'Candidatus Desulfovibrio trichonymphae' in the anterior part of the host cell. The draft genome of 'Ca. Adiutrix intracellularis' obtained from a metagenomic library revealed the presence of a complete gene set encoding the Wood-Ljungdahl pathway, including two homologs of fdhF encoding hydrogenase-linked formate dehydrogenases (FDHH ) and all other components of the recently described hydrogen-dependent carbon dioxide reductase (HDCR) complex, which substantiates previous claims that the symbiont is capable of reductive acetogenesis from CO2 and H2 . The close phylogenetic relationship between the HDCR components and their homologs in homoacetogenic Firmicutes and Spirochaetes suggests that the deltaproteobacterium acquired the capacity for homoacetogenesis via lateral gene transfer. The presence of genes for nitrogen fixation and the biosynthesis of amino acids and cofactors indicate the nutritional nature of the symbiosis.

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The Family Desulfobacteraceae

Cited by 69 publications

References 47 publications

Insights into the metabolic functioning of a multipartner ciliate symbiosis from oxygen‐depleted sediments

Insights into the metabolic functioning of a multipartner ciliate symbiosis from oxygen‐depleted sediments

Spatiotemporal analysis of microbial community dynamics during seasonal stratification events in a freshwater lake (Grand Lake, OK, USA)

‘Candidatus Adiutrix intracellularis’, an endosymbiont of termite gut flagellates, is the first representative of a deep‐branching clade of Deltaproteobacteria and a putative homoacetogen

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