Search

A novel Gram-negative, non-spore-forming, vibrio-shaped, anaerobic, alkaliphilic, sulfate-reducing bacterium, designated strain PAR22N T , was isolated from sediment samples collected at an alkaline crater lake in Guanajuato (Mexico). Strain PAR22N T grew at temperatures between 15 and 37 °C (optimum, 32 °C), at pH between pH 8.3 and 10.1 (optimum, pH 9.0-9.6), and in the presence of NaCl up to 10 %. Pyruvate, 2-methylbutyrate and fatty acids (4-18 carbon atoms) were used as electron donors in the presence of sulfate as a terminal electron acceptor and were incompletely oxidized to acetate and CO 2 . Besides sulfate, both sulfite and elemental sulfur were also used as terminal electron acceptors and were reduced to sulfide. The predominant fatty acids were summed feature 10 (C 18 : 1   ω7 c and/or C 18 : 1  ω9 t and/or C 18 : 1  ω12 t ), C 18 : 1   ω9 c and C 16 : 0 . The genome size of strain PAR22N T was 3.8 Mb including 3391 predicted genes. The genomic DNA G+C content was 49.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that it belongs to the genus Desulfobotulus within the class Deltaproteobacteria . Its closest phylogenetic relatives are Desulfobotulus alkaliphilus (98.4 % similarity) and Desulfobotulus sapovorans (97.9 % similarity). Based on phylogenetic, phenotypic and chemotaxonomic characteristics, we propose that the isolate represents a novel species of the genus Desulfobotulus with the name Desulfobotulus mexicanus sp. nov. The type strain is PAR22N T (=DSM 105758 T =JCM 32146 T ).

A novel anaerobic fermentative bacterium, strain SEBR 4209 T , was isolated from a water sample of a Congolese oil field. Strain SEBR 4209 T is phylogenetically related to the genus Pleomorphochaeta, in the family Spirochaetaceae. Its closest relatives are Pleomorphochaeta caudata SEBR 4223 T (94.5 % 16S rRNA gene sequence similarity) and Pleomorphochaeta multiformis MO-SPC2 T (94.3 % similarity). Like the other members of this genus, cells have a pleomorphic morphology, in particular an annular shape and long stalks. Optimal growth was observed at 37 °C, at pH between 6.8 and 7.0, and with 40 g l -1 NaCl. This strain was only able to grow by fermentation of carbohydrates. The fermentation products from glucose utilization were acetate, ethanol, CO2 and H2. Predominant fatty acids were C14 : 0, C14 : 0 DMA, C16 : 0 and C16 : 1ω7c. The major polar lipids were phosphoglycolipids, phospholipids and glycolipids. The G+C content of the DNA was 29.6 mol%. Based on phenotypic characteristics and phylogenetic traits, strain SEBR 4209 T is considered to represent a novel species of the genus Pleomorphochaeta, for which the name Pleomorphochaetanaphthae sp. nov. is proposed. The type strain is SEBR 4209 T (=DSM 104684 T =JCM 31871 T ).

Novel Gram-stain-negative, non-spore-forming, vibrio-shaped, anaerobic, alkaliphilic, sulfate-reducing bacteria, designated strains PAR180 T and PAR190, were isolated from sediments collected at an alkaline crater lake in Guanajuato (Mexico). Strain PAR180 T grew at temperatures between 15 and 40 °C (optimum 35 °C), and at pH between 8.3 and 10.4 (optimum 9). It was halotolerant, growing with up to 8 % (w/v) NaCl. Lactate, formate, pyruvate and ethanol were used as electron donors in the presence of sulfate and were incompletely oxidized to acetate and CO2. The isolate was able to grow with hydrogen and with CO2 as a carbon source. Beside sulfate, sulfite and thiosulfate were used as terminal electron acceptors. The isolate was able to grow by disproportionation of sulfite and thiosulfate, but not elemental sulfur, using acetate as a carbon source. The predominant fatty acids were C16 : 0, C16 : 1ω7c and summed feature 10 (C18 : 1ω7c and/or C18 : 1ω9t and/or C18 : 1ω12t). The DNA G+C content was 56.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that it belongs to the genus Desulfonatronum, class Deltaproteobacteria. Its closest relative is Desulfonatronum thiosulfatophilum (98.7 % 16S rRNA gene sequence similarity). The DNA-DNA relatedness value between strain PAR180 T and the type strain of D. thiosulfatophilum was 37.1±2.5 %. On the basis of phylogenetic, phenotypic and chemotaxonomic characteristics, the isolates is considered to represent a novel species of the genus Desulfonatronum, for which the name Desulfonatronum parangueonense sp. nov. is proposed. The type strain is PAR180 T (=DSM 103602 T =JCM 31598 T ).

A novel sulfate-reducing bacterium designated strain BE2801(T) was isolated from oil-polluted estuarine sediments (Berre Lagoon, France). Cells were Gram-stain-negative, motile, slightly curved or vibrioid rods. Optimal growth of strain BE2801(T) occurred at 30-32 °C, 0.5-1.5% NaCl (w/v) and pH 7.2-7.4. Strain BE2801(T) grew with C4 to C20 fatty acids or C12 to C20 n-alkenes as electron donors. Acetate and carbon dioxide were the oxidation products. The major cellular fatty acids were C16 : 0, C(16 : 1)ω7c and C(18 : 1)ω7. The DNA G+C content was 50.2 mol%. 16S rRNA and dsrAB gene sequence analysis indicated that strain BE2801(T) was a member of the family Desulfobacteraceae within the class Deltaproteobacteria. DNA-DNA hybridization with the most closely related taxon demonstrated 14.8 % relatedness. Based on phenotypic and phylogenetic evidence, strain BE2801(T) ( = DSM 25524(T) = JCM 18157(T)) is proposed to be a representative of a novel species of the genus Desulfatiferula, for which the name Desulfatiferula berrensis sp. nov. is suggested.

Magnetotactic bacteria synthesize intracellular magnetite and/or greigite magnetosome crystals. They play a significant role in both iron and sulfur cycles in sedimentary aquatic environments. To get insight into the bio-geochemical contribution of MTB, more studies concerning their ecology and their distribution in diverse habitats are necessary. The MTB community of an oil-industry polluted area of the French Mediterranean coast has been previously investigated. Here, we investigate the MTB community from coastal sediments of a Mediterranean pristine area using optical and transmission electron microscopy and phylogenetic analysis based on 16S rRNA gene sequences. A particularly high diversity of MTB was observed, with cocci phylogenetically distributed across the order Magnetococcales, including a novel cluster with sequences from the Mediterranean Sea designated as 'Med group', and novel morphotypes. [ABSTRACT FROM AUTHOR]