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Biomedical subjects

R R Ray

Publications and source records attributed to R R Ray.

7 recordsLinked to original sources
PubMed1996

Induction and carbon catabolite repression in the biosynthesis of beta-amylase by Bacillus megaterium B6.

Biosynthesis of extracellular beta-amylase in Bacillus megaterium B6 was induced by starch, although maltodextrin was found to be the actual inducer. Amongst the carbon sources tested, glucose was found to be the most potent repressor and when added exogenously to a starch-induced culture it brought about an immediate fall in enzyme synthesis through carbon catabolite repression. The repression was not overcome after the fall of glucose concentration in the culture medium below a critical level. This "catabolite repression" exerted by glucose was partially relieved by exogenous cyclic guanosine monophosphate (CGMP) and its dibutyryl derivative. On the other hand, guanosine monophosphate (GMP) was found to restore the original extent of enzyme synthesis in glucose repressed cells.

Anti-Bacterial Agents↗
PubMed1994

Biochemical approaches of increasing thermostability of beta-amylase from Bacillus megaterium B6.

Studies on the irreversible thermoinactivation of beta-amylase from Bacillus megaterium B6 exposed to 60 degrees C revealed that the deactivation mechanism probably results from the oxidation of thiols present at the active site of the enzyme. Several attempts were made to increase its thermostability, which indicated that Mn2+ played a key role in determining thermostability and partially reactivating the inactivated enzyme. Immobilization of beta-amylase through gel-entrapment and covalent crosslinking brought about a remarkable increase in thermotolerance with about a 14-fold increase in catalytic half-life.

Bacillus megaterium↗
PubMed1983

Effect of liposomal encapsulation of cis-platinum diamminodichloride in the treatment of Ehrlich ascites carcinoma.

cis-Platinum diamminodichloride (II) encapsulated in neutral liposomes has been used to enhance the activity of the drug on Ehrlich ascites carcinoma in mice. Both in vitro and in vivo experiments have revealed that better regression in tumor growth and cure, could be achieved with a lower dose, having apparently no toxic effect, by liposomal encapsulation of the drug.

Animals↗