Sphaerochaeta

• Main Authors: Nazina, Tamara N., Bidzhieva, Salimat K., Grouzdev, Denis S., Löffler, Frank E.
• Other Authors: Dedysh, Svetlana N.
• Format: Other/Unknown Material
• Language: English
• Published: Wiley 2021
• Subjects: Antarctic; Arctic; Antarc*; permafrost
• Online Access: http://dx.doi.org/10.1002/9781118960608.gbm02038; https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781118960608.gbm02038; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/9781118960608.gbm02038

Abstract Sphae.ro.chae'ta. Gr. n. sphaira (Latin transliteration sphaera ), a sphere; Gr. fem. n. chaitê (Latin transliteration chaeta ), long flowing hair; N.L. fem. n. Sphaerochaeta round cells along threads of hair, indicative of a round morphology with a derivation from spirochaetal ancestry. Spirochaetes / Spirochaetia / Spirochaetales / Sphaerochaetaceae / Sphaerochaeta The genus Sphaerochaeta comprises nonspiral, pleomorphic, and anaerobic spirochetes with fermentative metabolism. Spherical cells of diverse size, 0.3–2.5 μm in diameter, nonmotile, without flagella or periplasmic flagella‐like structure, non‐spore‐forming, and Gram‐negative. The cells occur as spherical aggregates, 3–25 μm in diameter, comprising up to 15 cells, surrounded by a membranous structure. Spiral morphology is not observed during any phase of the growth cycle. Cells lack ornithine or lysine peptidoglycan cross‐linkers. Mesophilic. Neutrophilic. Oxidase‐negative. Catalase gene present, but cells test catalase‐negative. Chemoorganoheterotrophic anaerobes. Fermentative growth occurs with carbohydrates, including pentose ( l ‐arabinose and d ‐xylose) and hexose ( d ‐galactose) monosaccharides, disaccharides (sucrose), and soluble starch. No growth with peptone, cellulose, xylan, and H 2 /CO 2 . The end products of carbohydrate fermentation vary between strains and include acetate, ethanol, propionate, formate, H 2 , and CO 2 . Yeast extract, casamino acids, and vitamins stimulate growth. Sulfate, sulfite, thiosulfate, nitrate, and oxygen are not used as electron acceptors. The major fatty acids are C 14:0 , C 16:0 , and C 16:1 ω9 c /C 18:1 ω9 c . Isoprenoid quinones are absent. Free living or associated with other prokaryotes. Habitats are anoxic river sediments, deep subsurface environments including petroleum reservoirs, Arctic permafrost sediments, biogas reactors, Antarctic brines, and groundwater aquifers. Genome sizes vary from 2.87 to 3.59 Mb. DNA G + C content (mol%) : 46–51 (genome sequences). Type species : Sphaerochaeta ...