|Taxonomy Citation ID||Reference|
( 2003 )
Novosphingobium tardaugens sp. nov., an oestradiol-degrading bacterium isolated from activated sludge of a sewage treatment plant in Tokyo.
PMID : 12656151 DOI : 10.1099/ijs.0.02301-0
An oestradiol-degrading bacterium isolated at a sewage treatment plant in Tokyo was studied phenotypically, genotypically and phylogenetically. Analysis of its 16S rDNA sequence, DNA base composition, whole-cell fatty acid profile and isoprenoid quinone composition, as well as the presence of sphingoglycolipid, revealed that the isolate is a member of the genus Novosphingobium. However, the sequence similarity of its 16S rDNA to those of known Novosphingobium species was no higher than 97%, implying that the isolate is distinctive. The results of DNA-DNA hybridization experiments and physiological characterization also indicated that the isolate represents a novel Novosphingobium species, for which the name Novosphingobium tardaugens sp. nov. is proposed; strain ARI-1T (=JCM 11434T =ATCC BAA-531T =IFO 16725T) is the type strain.
( 2002 )
Emendation of the genus Sphingomonas Yabuuchi et al. 1990 and junior objective synonymy of the species of three genera, Sphingobium, Novosphingobium and Sphingopyxis, in conjunction with Blastomonas ursincola.
PMID : 12361250 DOI : 10.1099/00207713-52-5-1485
The 16S rDNA sequence similarities between the type strains of Sphingomonas paucimobilis and 32 other Sphingomonas species range from 90.2 to 99.6%. It might be possible to divide the genus into several new genera according to a dendrogram drawn from 16S rDNA sequence similarity. However, the phenotypic and biochemical information needed to define clusters of strains representing distinct genera within this group of organisms was not previously available. Although the cellular lipids of type strains of all 28 Sphingomonas species tested contained glucuronosyl-(1 --> 1)-ceramide together with 2-hydroxymyristic acid, other molecular species of sphingoglycolipids were distributed randomly. Sphingomonas natatoria and Sphingomonas ursincola, bacteriochlorophyll a-containing, gram-negative facultative phototrophs, belong to the cluster of the genus Sphingomonas. Other phototrophic Porphyrobacter and Erythrobacter species in the Sphingomonadaceae were classified into a cluster different from the genus Sphingomonas, as reported previously. None of the physiological and biochemical characteristics considered, including cellular lipids and fatty acid composition, provided evidence for the division of the current genus Sphingomonas. It is therefore concluded that the genus Sphingomonas should remain undivided at this time. The species of three recently proposed genera, Sphingobium, Novosphingobium and Sphingopyxis, in conjunction with Blastobacter ursincola, are junior objective synonyms of species of the genus Sphingomonas.