Poly- β-hydroxybutyrate accumulation in Nostoc muscorum: Effects of metabolic inhibitors

• Published in: Journal of plant physiology 2007-03, Vol.164 (3), p.312-317
• Main Authors: Mallick, Nirupama, Sharma, Laxuman, Kumar Singh, Akhilesh
• Format: Article
• Language: English
• Subjects: Azaserine; Biological and medical sciences; butyric acid; Cyanobacteria; Cyanophyta; Diacetyl; Diuron; Fluoroacetates; Fundamental and applied biological sciences. Psychology; Hydroxybutyrates - metabolism; Metabolic inhibitors; metabolism; Methionine Sulfoximine; Non agrochemicals pollutants; Nostoc muscorum; Nostoc muscorum - metabolism; phosphates; Phosphates - metabolism; Phytopathology. Animal pests. Plant and forest protection; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; Poly- β-hydroxybutyrate; poly-beta-hydroxybutyrate; Polyesters - metabolism; Uncoupling Agents
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2006.01.012

Poly- β-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 α-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.