A facultatively anaerobic, marine spirochaete, designated strain SIP1T, was isolated from interstitial water from a cyanobacteria-containing microbial mat. Cells of strain SIP1T were 0.3–0.4×10–12 μm in size, helical with a body pitch of approximately 1.4 μm and motile by means of two to four periplasmic flagella (one, or occasionally two, being inserted near each end of the cell). Cells were catalase-negative and used a variety of monosaccharides and disaccharides and pectin as energy sources, growing especially well on cellobiose. Neither organic acids nor amino acids were utilized as energy sources. One or more amino acids in tryptone and one or more components of yeast extract were required for growth. Growth was observed at 9–37 °C (optimally at or near 37 °C), at initial pH 5–8 (optimally at initial pH 7.5) and in media prepared with 20–100 % (v/v) seawater (optimally at 60–80 %) or 0.10–1.00 M NaCl (optimally at 0.30–0.40 M). The products of cellobiose fermentation were acetate, ethanol, CO2, H2 and small amounts of formate. Aerated cultures performed incomplete oxidation of cellobiose to acetate (and, presumably, CO2) plus small amounts of ethanol and formate, but exhibited a Y cellobiose that was only slightly greater than that of cellobiose-fermenting anoxic cultures. The G+C content of the genomic DNA of strain SIP1T was 41.4 mol%, the lowest among known spirochaetas. On the basis of its 16S rRNA gene sequence, strain SIP1T was grouped among other members of the genus Spirochaeta, but it bore only 89 % similarity with respect to its closest known relatives, Spirochaeta litoralis and Spirochaeta isovalerica, two marine obligate anaerobes. On the basis of its phenotypic properties and phylogenetic position, strain SIP1T represents a novel species of the genus Spirochaeta, for which the name Spirochaeta cellobiosiphila sp. nov. is proposed. The type strain is SIP1T (=ATCC BAA-1285T =DSM 17781T).
A pale-pink strain (CCUG 53370T) from water was investigated by a polyphasic taxonomic approach. The cells stained Gram-positive and were rod-shaped and non-spore-forming. Analyses using the 16S rRNA gene sequence of the isolate showed that the organism belongs to the genus Deinococcus, with the highest sequence similarities to the type strains of Deinococcus ficus (94.4 %), Deinococcus navajonensis (94.3 %) and Deinococcus mumbaiensis (94.3 %). Chemotaxonomic data revealed that CCUG 53370T contains exclusively menaquinone MK-8 as the respiratory quinone and a complex polar lipid profile consisting of different unidentified glycolipids and polar lipids, two unknown phospholipids and three unknown phosphoglycolipids. As in other deinococci, one of these phosphoglycolipids was predominant in the profile, and it was identified in Deinococcus radiodurans as 2′-O-(1,2-diacyl-sn-glycero-3-phospho)-3′-O-(α-galactosyl)-N-d-glyceroyl alkylamine. Predominant fatty acids were C16 : 1 ω7c, C17 : 1 ω8c and C17 : 1 ω9c. Biochemical and chemotaxonomic properties demonstrate that strain CCUG 53370T represents a novel species, for which the name Deinococcus aquatilis sp. nov. is proposed. The type strain is CCUG 53370T (=CCM 7524T).
A unicellular cyanobacterium, designated KORDI 51-2T, was isolated from surface seawater of Chuuk lagoon, Micronesia. The cells were wine-coloured rods and emitted red fluorescence under green excitation of an epifluorescence microscope. Thus, morphologically, the strain resembled Synechococcus species. However, based on 16S rRNA gene sequence similarities between strain KORDI 51-2T and related strains belonging to cyanobacteria, the novel strain was distantly related to members of the ‘Halothece’ cluster. However, sequence similarities between strain KORDI 51-2T and members of the ‘Halothece’ cluster were very low, ranging from 90.7 to 92.1 %, and phylogenetic analyses showed that the strain formed a distinct branch. Therefore, a polyphasic characterization including morphology, physiology and pigment composition was conducted to elucidate the taxonomic position of strain KORDI 51-2T. The strain grew within a temperature range of 25–35 °C and a salinity range of 2–7 %. The optimal temperature and salinity were about 30 °C and 5 %, respectively. Strain KORDI 51-2T contained phycoerythrin, and the dominant carotenoid pigments were zeaxanthin, β-carotene and echinenone. The DNA G+C content was 60.5 mol%. Based on phylogenetic analysis of the 16S rRNA gene sequence, and the physiological data and pigment compositions, strain KORDI 51-2T is considered to represent a new genus and novel species of cyanobacteria for which the name Rubidibacter lacunae gen. nov., sp. nov. is proposed. The type strain is KORDI 51-2T (=KCTC 40015T=UTEX L2944T).
We report here the identification, characterization and culture of a Gram-negative to Gram-variable, rod-shaped, non-spore-forming anaerobic bacterium (strain FM1025T) isolated from the caecum of a duck. Phylogenetic analysis based on comparative 16S rRNA gene sequencing showed that this strain clustered with species of the family ‘Acidaminococcaceae’, with 94.9 % similarity to Megamonas hypermegale DSM 1672T and less than 91 % similarity with type strains of Pectinatus species. Sequence similarities of at least 98–99 % were observed with numerous sequences deposited in GenBank of uncultured strains from human and chicken caecal contents, but this strain is the first isolate of this taxon to be cultivated and described. On the basis of morphological, physiological and phylogenetic features, this strain should be assigned to a novel species in the genus Megamonas, for which the name Megamonas rupellensis sp. nov. is proposed. The type strain is strain FM1025T (=DSM 19944T =CIP 109788T).