title: Induction of osmoadaptive mechanisms and modulation of cellular physiology help Bacillus licheniformis strain SSA 61 adapt to salt stress.
abstract: Bacillus licheniformis strain SSA 61, originally isolated from Sambhar salt lake, was observed to grow even in the presence of 25 % salt stress. Osmoadaptive mechanisms of this halotolerant B. licheniformis strain SSA 61, for long-term survival and growth under salt stress, were determined. Proline was the preferentially accumulated compatible osmolyte. There was also increased accumulation of antioxidants ascorbic acid and glutathione. Among the different antioxidative enzymes assayed, superoxide dismutase played the most crucial role in defense against salt-induced stress in the organism. Adaptation to stress by the organism involved modulation of cellular physiology at various levels. There was enhanced expression of known proteins playing essential roles in stress adaptation, such as chaperones DnaK and GroEL, and general stress protein YfkM and polynucleotide phosphorylase/polyadenylase. Proteins involved in amino acid biosynthetic pathway, ribosome structure, and peptide elongation were also overexpressed. Salt stress-induced modulation of expression of enzymes involved in carbon metabolism was observed. There was up-regulation of a number of enzymes involved in generation of NADH and NADPH, indicating increased cellular demand for both energy and reducing power.
authors.affiliation: Division of Microbiology, Indian Agricultural Research Institute, New Delhi, 10012, India, sangeeta_paul2003@yahoo.co.in.
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Paul
authors.forename: Chetana
authors.initials: C
authors.lastname: Aggarwal
authors.forename: Jyoti Kumar
authors.initials: JK
authors.lastname: Thakur
authors.forename: G S
authors.initials: GS
authors.lastname: Bandeppa
authors.forename: Md Aslam
authors.initials: MA
authors.lastname: Khan
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Pearson
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Babnigg
authors.forename: Carol S
authors.initials: CS
authors.lastname: Giometti
authors.forename: Andrzej
authors.initials: A
authors.lastname: Joachimiak
mesh_terms: D000222:Adaptation, Physiological; D001205:Ascorbic Acid / Q000032:analysis; D001407:Bacillus / Q000187:drug effects* / Q000502:physiology*; D020869:Gene Expression Profiling; D005978:Glutathione / Q000032:analysis; D060106:Lakes; D050296:Microbial Viability / Q000187:drug effects; D009997:Osmotic Pressure; D011392:Proline / Q000032:analysis; D012492:Salts / Q000378:metabolism*; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D012492:Salts; D011392:Proline; D013482:Superoxide Dismutase; D005978:Glutathione; D001205:Ascorbic Acid