title: Cell surface characteristics of two halotolerant strains of Sinorhizobium meliloti.
abstract: The halotolerant Sinorhizobium meliloti strain Rmd201 and its variant Rmd201 a were examined for their cell surface properties. The variant strain formed rough colonies and was found to be more hydrophobic. Growth of the variant strain was not affected appreciably when NaCl concentration of the medium was increased from 2 mM to 700 mM. Exopolysaccharide (EPS) and the lipopolysaccharide (LPS) content of the variant strain was found to be 7 and 14 times less, respectively, than the parent strain. However, enhanced synthesis of high molecular weight LPS bands were observed in SDS-PAGE analysis in the variant strain when the NaCl concentration was raised from 2 mM to 700 mM. Ribose and glucosamine were present in the variant LPS only. Mannose appeared as a major LPS constituent of the variant when grown in high salt containing medium. All these cell surface characteristics indicated that there were significant differences between the halotolerant strains of S. meliloti. The changes in the cell surface of the variant strain indicated the possible mutation in the gene(s) of cell surface polysaccharide biosynthesis.
authors.affiliation: Institute of Genomics and Integrative Biology, Formerly-Centre for Biochemical Technology, Mall Road, Delhi University Campus, Delhi 110 007, India.
authors.forename: Indranil
authors.initials: I
authors.lastname: Bhattacharya
authors.forename: Hasi R
authors.initials: HR
authors.lastname: Das
mesh_terms: D002462:Cell Membrane; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D057927:Hydrophobic and Hydrophilic Interactions; D008070:Lipopolysaccharides / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry; D009005:Monosaccharides / Q000032:analysis; D010641:Phenotype; D011135:Polysaccharides, Bacterial / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry; D016962:Sinorhizobium meliloti / Q000737:chemistry / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D012965:Sodium Chloride / Q000494:pharmacology*; D013499:Surface Properties
chemical_list: D003470:Culture Media; D008070:Lipopolysaccharides; D009005:Monosaccharides; D011135:Polysaccharides, Bacterial; D012965:Sodium Chloride