title: Identification of maltooligosyltrehalose synthase and maltooligosyltrehalose trehalohydrolase enzymes catalysing trehalose biosynthesis in Anabaena 7120 exposed to NaCl stress.
abstract: Anabaena 7120 cells were exposed to NaCl (25-175 mM) stress. Maximum growth was recorded in media containing 150mM NaCl. Short-term exposure (48h) of the cyanobacterial biomass to 150mM NaCl, induced highest trehalose level (37mM). Control cells lacking NaCl did not show any trace of trehalose as ascertained by NMR and HPLC analysis. Trehalose biosynthesis observed with NaCl plus high temperature (40 degrees C) indicated that its production was specifically triggered by NaCl, not temperature. The increase in trehalose level during NaCl stress was the result of overexpression of the trehalose-forming enzymes maltooligosyltrehalose synthase (MTSase), EC 5.4.99.15 (114kDa) and maltooligosyltrehalose trehalohydrolase (MTHase), EC 3.2.1.141 (68 kDa) as evidenced by SDS-PAGE analysis. To our knowledge this is the first report of induced trehalose biosynthesis in Anabaena 7120 during salt-stress, accompanied by identification of MTSase and MTHase enzymes on gel. It is suggested that Anabaena 7120 cells synthesize the osmolyte trehalose to withstand osmotic fluctuations.
authors.affiliation: Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi 221005, India. asthana_ravi@rediffmail.com
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Asthana
authors.forename: Subhasha
authors.initials: S
authors.lastname: Srivastava
authors.forename: Akhilesh P
authors.initials: AP
authors.lastname: Singh
authors.forename: Arvind M
authors.initials: AM
authors.lastname: Kayastha
authors.forename: Sureshwar P
authors.initials: SP
authors.lastname: Singh
mesh_terms: D017033:Anabaena / Q000187:drug effects / Q000201:enzymology*; D004305:Dose-Response Relationship, Drug; D005959:Glucosidases / Q000302:isolation & purification / Q000378:metabolism*; D005964:Glucosyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*; D014199:Trehalose / Q000096:biosynthesis*
chemical_list: D012965:Sodium Chloride; D014199:Trehalose; D005964:Glucosyltransferases; C099084:maltooligosyl trehalose synthase; D005959:Glucosidases; C099156:maltooligosyl trehalose trehalohydrolase