Desulfonatronobacter acidivorans gen. nov., sp. nov., and Desulfobulbus alkaliphilus sp. nov., haloalkaliphilic heterotrophic sulfate-reducing bacteria from soda lakes

Two types of heterotrophic sulfate-reducing bacteria (SRB) were isolated from anoxic sediments of hypersaline soda lakes in Kulunda Steppe (Altai, Russia). The isolates used propionate as an energy and carbon source. Strain APT2T was enriched and isolated with thiosulfate as the electron acceptor. Strains APS1T and ASS1 were isolated with sulfate. Strain APT2T was a short rod and motile with a single subpolar flagellum, while strains APS1T and ASS1 were lemon-shaped oval rods and motile with a single polar flagellum and thin flagella-like filaments. Strain APT2T grew by complete oxidation of C3-C8 fatty acids with thiosulfate or sulfate as the electron acceptor, while strains APS1T and ASS1 were much less versatile and utilized only propionate and pyruvate as the electron donor and carbon source with sulfate or sulfite as the electron acceptor. Furthermore, strains APS1T and ASS1 oxidized propionate incompletely to form acetate. All of the isolates were moderately halophilic and obligately alkaliphilic. Phylogenetic analysis based on 16S rRNA gene sequences placed the isolates in the order Desulfobacterales of the class Deltaproteobacteria. Strain APT2T belonged to the family Desulfobacteraceae and clustered with a halophilic SRB, Desulfosalsimonas propionicica PropAT. Strains APS1T and ASS1 were closely related to each other and clustered with the genus Desulfobulbus of the family Desulfobulbaceae. On the basis of phenotypic and phylogenetic analysis, the isolates are proposed to represent two novel taxa, Desulfonatronobacter acidivorans gen. nov., sp. nov. (type strain of the type species APT2T = DSM 24257T = UNIQEM U853T) and Desulfobulbus alkaliphilus sp. nov. (type strain APS1T = DSM 24258T = UNIQEM U900T)

Sulfidogenesis in hypersaline chloride-sulfate lakes of Kulunda Steppe (Altai, Russia)

The activity and culturable diversity of sulfidogens were investigated in anoxic sediments of four hypersaline lakes with pH 7.6-8.2 in the Kulunda Steppe (Altai, Russia). Sulfate reduction rates were low, varying from 0.1 to 6.0 nmol HS−/(cm3 h) with a maximum in the top 10 cm layer. Potential sulfidogenic rates with thiosulfate and sulfur as the e-acceptors were higher than with sulfate and were stimulated by formate, lactate, and acetate. Sulfidogenesis was optimal at salt concentrations below 2 M NaCl. Cultivation at 2 M NaCl resulted in the isolation of several strains of moderately halophilic SRB, but no growth of SRB was observed at 4 M NaCl. At lithotrophic conditions (i.e., with formate or H2 as e-donors), several closely related alkalitolerant strains belonging to the genus Desulfonatronovibrio were isolated. Enrichments at heterotrophic conditions with lactate, propionate, acetate, or butyrate using sulfate or thiosulfate as e-acceptors yielded isolates related to Desulfosalsimonas propionicica, Desulfohalobium utahense, and Desulfocella halophila. Sulfur-reducing enrichments at 2 M NaCl with ethanol produced a member of the genus Halanaerobium, while enrichments at 4 M NaCl with acetate were dominated by archaea, demonstrating for the first time such type of catabolism in haloarchaea

Метафизика творческого поиска

Монография «Метафизика научного поиска» является коллективной научной работой, которая посвящена продолжению систематического обобщения, изложения идей и опыта работы членов секции «Теория и методология творчества» Российского Философского общества. Работа может быть полезной для исследователей креативной проблематики, для интересующихся проблемами творчества, для студентов и аспирантов, а также для подготовки курсов и спецкурсов по философии культуры, философии творчества, для всех, кто имеет интерес к рассматриваемой проблематике