Mucilaginibacter roseus sp. nov., isolated from a freshwater river

Abstract

A bacterial strain, designated TTM-1 T , was isolated from a water sample taken from the Caohu River in Taiwan and characterized in a taxonomic study using a polyphasic approach. Cells of strain TTM-1 T were Gram-stain-negative, aerobic, non-motile, rod-shaped and covered by large capsules, and formed pink-coloured colonies. Growth occurred at 10-37 8C (optimum 30-37 8C), at pH 6-8 (optimum pH 6-7) and with 0-2 % NaCl (optimum 0.5 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain TTM-1 T belonged to the genus Mucilaginibacter and was most closely related to Mucilaginibacter defluvii A5 T with a 16S rRNA gene sequence similarity of 97.3 %. The predominant fatty acids of strain TTM-1 T were summed feature 3 (C 16 : 1 v7c and/or C 16 : 1 v6c; 37.1 %) and iso-C 15 : 0 (30.7 %). The polar lipid profile consisted of phosphatidylethanolamine and several uncharacterized aminophospholipids and phospholipids. The major isoprenoid quinone was MK-7. The DNA G+C content of the genomic DNA was 45.1 mol%. The DNA-DNA relatedness of strain TTM-1 T with respect to recognized species of the genus Mucilaginibacter was less than 70 %. On the basis of the phylogenetic inference and phenotypic data, strain TTM-1 T represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter roseus sp. nov. is proposed. The type strain is TTM-1 T (5LMG 28454 T 5KCTC 42273 T ). , 2011). At the time of writing, this genus comprises 33 species with validly published names (http://www. bacterio.net/mucilaginibacter.html). Cells of members of the genus Mucilaginibacter are Gram-stain-negative, non-motile, non-spore-forming and rod-shaped. Chemotaxonomically, cells possess MK-7 as the major respiratory quinone, phosphatidylethanolamine as the major polar lipid, iso-C 15 : 0 and summed feature 3 (C 16 : 1 v7c and/or C 16 : 1 v6c) as the predominant fatty acids, and DNA G+C contents between 39.1 and 47.2 mol%. The present study was carried out to clarify the taxonomic position of a strain identified as a novel species of the genus Mucilaginibacter by using a polyphasic approach. The genusDuring our investigations on the biodiversity of bacteria in the water of the Caohu River (GPS location: 248 049 240 N 1208 469 040 E) in the vicinity of Taichung city, Taiwan, a novel pink-pigmented bacterium, designated TTM-1 T , was isolated and selected for detailed taxonomy analyses. Strain TTM-1 T was isolated on R2A agar (BD Difco) after incubation at 25 8C for 3 days, subcultured under the same conditions and stored at 280 8C in R2A broth (BD Difco) with 20 % (v/v) glycerol or by lyophilization.Genomic DNA was isolated using a bacterial genomic DNA purification kit (DP02-150; GeneMark Technology) and the 16S rRNA gene was sequenced and analysed as described previously by Chen et al. (2001). Primers FD1 (59-AGAGTTTGATCCTGGCTCAG-39) and RD1 (59-AAGGAGGTGATCCAG CC-39) were used for amplification of bacterial 16S rRNA genes by PCR (Weisburg et al., 1991;Anzai et al., 1997). These primers correspond to nucleoti...