RESUMEN

A Gram-stain-negative, motile, alkali-tolerant, swollen-rod shaped, reddish brown coloured, phototrophic bacterium designated as strain JA980T, was isolated from freshwater sampled at Umiam lake, Shillong, India. Strain JA980T grew well up to pH 9.0. Respiratory quinones were ubiquinone 10 and rhodoquinone 10. The major fatty acid was C18: 1ω7c/C18:1ω6c with minor amounts of C18:0, C16:0, C18:0 3-OH and C16:0 3-OH. Strain JA980T contained bacteriochlorophyll-a and carotenoids of the spirilloxanthin series. The polar lipids of strain JA980T comprised phosphatidylethanolamine, phosphatidylcholine, diphosphatidylglycerol, an unidentified phospholipid, unidentified amino lipids (AL1,3,4,5) and an unidentified lipid (L1). Strain JA980T had the highest (99.57 %) 16S rRNA gene sequence similarity to the type strains of Rhodomicrobium vannielii ATCC17100T and Rhodomicrobium udaipurense JA643T. The genome of strain JA980T was 3.88 Mbp with a DNA G+C content of 62.4 mol%. Based on the results of phylogenetic analyses, low in silico DNA-DNA hybridization values (33 %), low (87 %) average nucleotide identity results, chemotaxonomic characteristics and differential physiological properties, strain JA980T could not be classified into either of the two recognized species of the genus Rhodomicrobium, suggesting that it represents a novel species, for which the name Rhodomicrobium lacus sp. nov. is proposed. The type strain is JA980T (=KCTC 15697T= MCC 3714T= NBRC 113803T).

Asunto(s)

Lagos/microbiología , Filogenia , Rhodomicrobium/clasificación , Técnicas de Tipificación Bacteriana , Bacterioclorofila A/química , Composición de Base , Carotenoides/química , ADN Bacteriano/genética , Ácidos Grasos/química , India , Hibridación de Ácido Nucleico , Fosfolípidos/química , Pigmentación , ARN Ribosómico 16S/genética , Rhodomicrobium/aislamiento & purificación , Análisis de Secuencia de ADN , Ubiquinona/análogos & derivados , Ubiquinona/química , Microbiología del Agua

RESUMEN

Two strains (JA643(T) and JA755) of Gram-stain-negative, facultatively anaerobic phototrophic, bacteria capable of growth at low temperatures (10-15 °C) were isolated from freshwater streams from different geographical regions of India. Both strains contain bacteriochlorophyll a and carotenoids of the spirilloxanthin series. Phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified phospholipid (PL), unidentified amino lipids (AL1-AL6, AL9) and an unidentified lipid (L1) were the polar lipids present in both strains. The major cellular fatty acid was C18 : 1ω7c (76-79 % of the total). Bacteriohopane derivatives (BHD1,2), unidentified hopanoids (UH1-5), diplopterol (DPL) and diploptene (DPE) were the major hopanoids of both strains. The DNA G+C content was 64.2-64.5 mol%. 16S rRNA gene sequence-based phylogenetic analysis showed that both strains are closely related to the genus Rhodomicrobium and clustered with Rhodomicrobium vannielii DSM 162(T) (99 % sequence similarity). However, both strains exhibited only 46.1 % DNA-DNA hybridization with R. vannielii DSM 162(T). Strains JA643(T) and JA755 shared >99 % 16S rRNA gene sequence similarity and were >85 % related on the basis of DNA-DNA hybridization; they are therefore considered to represent a novel species in the genus Rhodomicrobium, for which the name Rhodomicrobium udaipurense sp. nov. is proposed. The type strain is JA643(T) ( = KCTC 15219(T) = NBRC 109057(T)).

Asunto(s)

Filogenia , Rhodomicrobium/clasificación , Ríos/microbiología , Técnicas de Tipificación Bacteriana , Bacterioclorofila A/análisis , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/análisis , India , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Fosfolípidos/análisis , ARN Ribosómico 16S/genética , Rhodomicrobium/genética , Rhodomicrobium/aislamiento & purificación , Análisis de Secuencia de ADN , Triterpenos/análisis