A Microbial Biorealm page on the genus Psychroflexus sediminis
Higher order taxa
Cellular organisms; Bacteria; Bacteroidetes/Chlorobi group; Bacteroidetes; Flavobacteriia; Flavobacteriales; Flavobacteriacease; Psychroflexus
Description and significance
Psychroflexus sediminis is a gram negative, non-motile, obligatory aerobic bacterium. It has straight to slightly curved rod shape, and it's mesophilic, slightly halophilic, psychrophilic, catalase- and oxidase-positive. The optimum condition for its growth is 25-30 °C with 2-3% NaCl, and its optimum pH is 7.0-8.0. It has been represented and supported as a novel species of the genus Psychroflexus by the combination of phylogenetic analysis, DNA–DNA hybridization data, phenotypic characteristics and chemotaxonomic differences.
The genomic DNA G+C content was 35.8 mol%. An almost-complete 16S rRNA gene sequence was determined, and the genomic size was 1475 bp. The type strain is YIM-C238T, and it's phylogenetically most closely related to P.tropicus ATCC BAA-734T. The level of DNA–DNA relatedness between the two strains was 8.4 %, which was far below the threshold value of about 70% for assigning strains to the same species.
Cell structure and metabolism
Cells are approximately 0.4–1.0 mm wide and 3.0–6.0 mm long, and endospores are not formed. Colonies are orange-pigmented, flat and non-translucent with glistening surfaces (2–3 mm in diameter after incubation for 3–5 days at 28 °C on MA), and non-diffusible orange carotenoid pigments are produced. Flexirubin pigments were absent. It hydrolyses aesculin, gelatin and Tweens 20 and 80, and nitrate is reduced to nitrite. It produces acids from gentiobiose, glycogen, D-lactose, maltose, sucrose, turanose and trehalose, and it oxidizes L alanyl glycine, L-aspartic acid, dextrin, glycogen, L-fucose, entiobiose, maltose, D-mannitol, methyl b-D-glucoside, D psicose, L-serine, succinic acid, sucrose, trehalose and Tween 80. It's major fatty acids are anteiso-C15 : 0 , 3-OH iso-C16 : 0 and anteiso-C15 : 1v 10c .
The Psychroflexus sediminis bacteria was isolated from a sediment sample collected from the Dachaidamu salt lake of the Qaidam Basin in Qinghai Province, north-west China, that had a salinity of 27.4%., and they were grown on marine agar, indicating that this bacteria prefers salty aquatic environments.
The pathology and their antibiotic sensitivity/resistance has not been discussed.
Chen, Y.-G., Cui, X.-L., Wang, Y.-X., Tang, S.-K., Zhang, Y.-Q., Li, W.-J., Liu, J.-H., Peng, Q. & Xu, L.-H. (2009). Psychroflexus sediminis sp. nov., a mesophilic bacterium isolated from salt lake sediment in China. Int J Syst Evol Microbiol 59, 569–573.
Edited by Shaghayegh Sabeti, student of Rachel Larsen at the University of Southern Maine