Poly-beta-hydroxybutyrate accumulation in Nostoc muscorum: effects of metabolic inhibitors.
Poly-beta-hydroxybutyrate (PHB) accumulation in Nostoc muscorum was studied in presence of various metabolic inhibitors. Supplementation of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) was found to suppress PHB accumulation in phosphate-limited N. muscorum under photoautotrophic growth condition. PHB accumulation increased up to 21% and 17% from an initial PHB content of 8.5% of dry weight, respectively, under carbonylcyanide m-chlorophenylhydrazone (CCCP) and dicyclohexylcarbodiimide (DCCD) treatment, whereas 2,4 -dinitrophenol (DNP) supplementation depicted insignificant effect on PHB pool of the test cyanobacterium. Supplementation of l-methionine-dl-sulfoximine (MSX) and azaserine was also found to increase PHB accumulation in N(2) -fixing and NH(4)(+) -grown N. muscorum, but not in NO(3)(-) -grown cells. The stimulatory action of monofluoroacetate on PHB accumulation was suppressed in presence of alpha-ketoglutarate and DCMU. Interestingly, 2,3 -butanedione supplementation was not only found inhibitory for accumulation of PHB in P-deficient, N-deficient and chemoheterotrophically grown N. muscorum but suppression of PHB synthesis was also evident in control cultures in presence of 2,3 -butanedione. The possible mechanisms are discussed.
Mallick
Nirupama
N
Agricultural and Food Engineering Department, Indian Institute of Technology, Kharagpur, India. nm@agfe.iitkgp.ernet.in
Sharma
Laxuman
L
Kumar Singh
Akhilesh
A
D001377:Azaserine; D003931:Diacetyl; D004237:Diuron; D005463:Fluoroacetates; D006885:Hydroxybutyrates / Q000378:metabolism*; D008717:Methionine Sulfoximine; D050502:Nostoc muscorum / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism*; D014475:Uncoupling Agents; D000094122:Polyhydroxybutyrates
D001377:Azaserine; D003931:Diacetyl; D004237:Diuron; D005463:Fluoroacetates; D006885:Hydroxybutyrates; D008717:Methionine Sulfoximine; D010710:Phosphates; D011091:Polyesters; D014475:Uncoupling Agents; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates; C014815:fluoroacetic acid