Thiospirochaeta

Thi.o.spi.ro.chae'ta. Gr. neut. n. theion sulfur; N.L. fem. n. Spirochaeta a bacterial genus; N.L. fem. n. Thiospirochaeta sulfur spirochete. Spirochaetota / Spirochaetia / Spirochaetales / Spirochaetaceae / Thiospirochaeta The genus Thiospirochaeta accommodates moderately halophilic aerotolerant anaerobic spirochetes isolated from the “Thiodendron” consortium consisting of spirochetes and sulfidogens. The genus includes a single species represented by one strain. Gram-stain negative cells can occur as three morphotypes: short cells with typical movement of spirochetes (anaerobic conditions), long nonmotile filaments with periplasmic sulfur globules (micro-oxic conditions with low sulfide concentrations), and round bodies (any unfavorable conditions). Cells form conglomerates immersed in a polysaccharide matrix under microaerobic conditions. Able to accumulate sulfur globules in the cell periplasm in the presence of sulfide in micro-oxic conditions. Capable of reducing sulfur and thiosulfate. Preferred substrates for growth are carbohydrates. Obligately fermentative metabolism with the production of formate, acetate, ethanol, CO2, and H2 during growth of glucose. The major fatty acids are iso-C14:0, iso-C15:0, anteiso-C15:0, and aldehyde C14:0. The genome of type strain, Thiospirochaeta perfilievii PT comprises one circular chromosome with a size of 3.67 Mb that contains 3,383 protein-coding genes and 73 RNA genes, including six operons of ribosomal RNA genes. Known habitats are saline sulfide springs and waters, littoral and sublittoral zones of the seas and oceans. DNA G + C content (mol%): 32.6 (genome analysis). Type species: Thiospirochaeta perfilievii Dubinina et al. 2020VP (basonym: Spirochaeta perfilievii Dubinina et al. 2011).