J. C. Bardhan

Bio: J. C. Bardhan is an academic researcher. The author has contributed to research in topics: Sterol. The author has an hindex of 1, co-authored 1 publications receiving 13 citations.

The bacterial oxidation of aromatic compounds.

Abstract: SUMMARY: Adaptive patterns for a vibrio indicate that the oxidation of phenylalanine to homogentisic acid by this organism may proceed by two different pathways, one through phenylpyruvic and phenylacetic acids and the other through tyrosine and p-hydroxyphenylpyruvic acid. That the former pathway is used is confirmed by the isolation from metabolism fluids of the phenylhydrazone of phenylpyruvic acid. The vibrio does not appear to oxidize the side chains of phenylpropionic and phenylacetic acids before ring fission. The influence of cell suspension density on rates of oxidation of various highly polar compounds which may penetrate slowly into the cells has been studied.

The bacterial oxidation of aromatic compounds; III. The enzymatic oxidation of catechol and protocatechuic acid to beta-ketoadipic acid.

Abstract: Evans (1947) observed that cultures of Vibrio 01 developing at the expense of phenol gave an intense violet Rothera reaction during the later stages of growth. The Rothera test is a nitroprusside reaction used clinically to detect the presence of \"acetone bodies\" (acetone and acetoacetic acid) in urine. Although Evans did not succeed in identifying the substance responsible for the positive Rothera reaction in cultures of Vibrio 01, he established the fact that it was an organic acid that was considerably less ether-soluble than acetoacetic acid. Subsequently Kilby (1948) isolated the acid from culture filtrates of Vibrio 01 and identified it as ,3-ketoadipic acid, a 6-carbon dicarboxylic acid. He concluded that it was an intermediate in the oxidation of the benzene ring. As reported in an earlier paper (Sleeper, Tsuchida, and Stanier, 1950), we have succeeded in obtaining dried cell preparations of Pseudomonasfluorescens capable of oxidizing catechol and protocatechuic acid. The dried cell preparations were found to attack both substrates with a much lower oxygen uptake per mole than that which occurs during the equivalent oxidations by living cells, a fact which suggested that the oxidations by dried cells are blocked at an early stage. The investigations reported in the present paper show that both aromatic compounds are converted quantitatively by dried cells into ,B-ketoadipic acid, thus confirming in a direct manner Kilby's inference that this aliphatic acid is an intermediate in the oxidations of aromatic compounds.

Regulation of aromatic metabolism in the fungi: metabolic control of the 3-oxoadipate pathway in the yeast Rhodotorula mucilaginosa.

Abstract: SUMMARY: The metabolic control of the protocatechuate branch of the 3-oxoadipate pathway in Rhodotorula mucilaginosa was examined and the specific inducers identified using appropriately blocked mutants. Three successive inductive events permitted the synthesis of the five enzymes converting p-hydroxybenzoate to 3-oxoadipyl-CoA: the independent induction of 4-hydroxybenzoate 3-mono-oxygenase by its own specific substrate, the independent induction of protocatechuate 3,4-dioxygenase by either protocatechuate or p-hydroxybenzoate, and finally the co-ordinate induction of 3-carboxymuconate cyclase, 3-carboxymucono-lactone hydrolase and 3-oxoadipate CoA-transferase by cither protocatechuate or p-hydroxybenzoate. Evidence is presented which suggests that R. mucilaginosa is unable to metabolize catechol or its usual precursors, and the significance of this is discussed in relation to control of the protocatechuate branch and the differing control mechanisms governing the synthesis of enzymes of the 3-oxoadipate pathway in other fungi and bacteria.