• Corrigendum: Fuerstia marisgermanicae gen. nov., sp. nov., an Unusual Member of the Phylum Planctomycetes From the German Wadden Sea.

      Kohn, Timo; Heuer, Anja; Jogler, Mareike; Vollmers, John; Boedeker, Christian; Bunk, Boyke; Rast, Patrick; Borchert, Daniela; Glöckner, Ines; Freese, Heike M; et al. (Frontiers, 2019-01-01)
    • Fuerstia marisgermanicae gen. nov., sp. nov., an Unusual Member of the Phylum Planctomycetes from the German Wadden Sea.

      Kohn, Timo; Heuer, Anja; Jogler, Mareike; Vollmers, John; Boedeker, Christian; Bunk, Boyke; Rast, Patrick; Borchert, Daniela; Glöckner, Ines; Freese, Heike M; et al. (Frontiers, 2016-01-01)
      Members of the phylum Planctomycetes are ubiquitous bacteria that dwell in aquatic and terrestrial habitats. While planctomycetal species are important players in the global carbon and nitrogen cycle, this phylum is still undersampled and only few genome sequences are available. Here we describe strain NH11T, a novel planctomycete obtained from a crustacean shell (Wadden Sea, Germany). The phylogenetically closest related cultivated species is Gimesia maris, sharing only 87% 16S rRNA sequence identity. Previous isolation attempts have mostly yielded members of the genus Rhodopirellula from water of the German North Sea. On the other hand, only one axenic culture of the genus Pirellula was obtained from a crustacean thus far. However, the 16S rRNA gene sequence of strain NH11T shares only 80% sequence identity with the closest relative of both genera, Rhodopirellula and Pirellula. Thus, strain NH11T is unique in terms of origin and phylogeny. While the pear to ovoid shaped cells of strain NH11T are typical planctomycetal, light-, and electron microscopic observations point toward an unusual variation of cell division through budding: during the division process daughter- and mother cells are connected by an unseen thin tubular-like structure. Furthermore, the periplasmic space of strain NH11T was unusually enlarged and differed from previously known planctomycetes. The complete genome of strain NH11T, with almost 9 Mb in size, is among the largest planctomycetal genomes sequenced thus far, but harbors only 6645 protein-coding genes. The acquisition of genomic components by horizontal gene transfer is indicated by the presence of numerous putative genomic islands. Strikingly, 45 "giant genes" were found within the genome of NH11T. Subsequent analysis of all available planctomycetal genomes revealed that Planctomycetes as such are especially rich in "giant genes". Furthermore, Multilocus Sequence Analysis (MLSA) tree reconstruction support the phylogenetic distance of strain NH11T from other cultivated Planctomycetes of the same phylogenetic cluster. Thus, based on our findings, we propose to classify strain NH11T as Fuerstia marisgermanicae gen. nov., sp. nov., with the type strain NH11T, within the phylum Planctomycetes.
    • Sulfate-Reducing Bacteria That Produce Exopolymers Thrive in the Calcifying Zone of a Hypersaline Cyanobacterial Mat.

      Spring, Stefan; Sorokin, Dimitry Y; Verbarg, Susanne; Rohde, M; Woyke, Tanja; Kyrpides, Nikos C; HZI, Helmholtz Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany. (Frontiers, 2019-01-01)
      Calcifying microbial mats in hypersaline environments are important model systems for the study of the earliest ecosystems on Earth that started to appear more than three billion years ago and have been preserved in the fossil record as laminated lithified structures known as stromatolites. It is believed that sulfate-reducing bacteria play a pivotal role in the lithification process by increasing the saturation index of calcium minerals within the mat. Strain L21-Syr-ABT was isolated from anoxic samples of a several centimeters-thick microbialite-forming cyanobacterial mat of a hypersaline lake on the Kiritimati Atoll (Kiribati, Central Pacific). The novel isolate was assigned to the family Desulfovibrionaceae within the Deltaproteobacteria. Available 16S rRNA-based population surveys obtained from discrete layers of the mat indicate that the occurrence of a species-level clade represented by strain L21-Syr-ABT is restricted to a specific layer of the suboxic zone, which is characterized by the presence of aragonitic spherulites. To elucidate a possible function of this sulfate-reducing bacterium in the mineral formation within the mat a comprehensive phenotypic characterization was combined with the results of a comparative genome analysis. Among the determined traits of strain L21-Syr-ABT, several features were identified that could play a role in the precipitation of calcium carbonate: (i) the potential deacetylation of polysaccharides and consumption of substrates such as lactate and sulfate could mobilize free calcium; (ii) under conditions that favor the utilization of formate and hydrogen, the alkalinity engine within the mat is stimulated, thereby increasing the availability of carbonate; (iii) the production of extracellular polysaccharides could provide nucleation sites for calcium mineralization. In addition, our data suggest the proposal of the novel species and genus Desulfohalovibrio reitneri represented by the type strain L21-Syr-ABT (=DSM 26903T = JCM 18662T).