title: Repression of oxalic acid-mediated mineral phosphate solubilization in rhizospheric isolates of Klebsiella pneumoniae by succinate.
abstract: Two strains of Klebsiella (SM6 and SM11) were isolated from rhizospheric soil that solubilized mineral phosphate by secretion of oxalic acid from glucose. Activities of enzymes for periplasmic glucose oxidation (glucose dehydrogenase) and glyoxylate shunt (isocitrate lyase and glyoxylate oxidase) responsible for oxalic acid production were estimated. In presence of succinate, phosphate solubilization was completely inhibited, and the enzymes glucose dehydrogenase and glyoxylate oxidase were repressed. Significant activity of isocitrate lyase, the key enzyme for carbon flux through glyoxylate shunt and oxalic acid production during growth on glucose suggested that it could be inducible in nature, and its inhibition by succinate appeared to be similar to catabolite repression.
authors.affiliation: Institute of Science, Nirma University, Sarkhej-Gandhinagar Highway, Ahmedabad 382481, Gujarat, India.
authors.forename: Mahendrapal Singh
authors.initials: MS
authors.lastname: Rajput
authors.forename: G
authors.initials: G
authors.lastname: Naresh Kumar
authors.forename: Shalini
authors.initials: S
authors.lastname: Rajkumar
mesh_terms: D042843:Glucose 1-Dehydrogenase / Q000378:metabolism; D006038:Glyoxylates / Q000378:metabolism; D007522:Isocitrate Lyase / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000378:metabolism*; D019815:Oxalic Acid / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*; D058441:Rhizosphere; D012988:Soil Microbiology; D019802:Succinic Acid / Q000494:pharmacology*
chemical_list: D006038:Glyoxylates; D010710:Phosphates; D019815:Oxalic Acid; D019802:Succinic Acid; D010088:Oxidoreductases; D042843:Glucose 1-Dehydrogenase; D007522:Isocitrate Lyase