Résumé
A bacterial strain was isolated from dhal industry red gram waste and identified as Bacillus. A thermostable extracellular amylase was partially purified from the strain. Optimum temperature and pH for the enzyme were found to be 60 degrees C and 6.5, respectively. The maximum amylase production was achieved with maltose as carbon source. Among the nitrogen sources, peptone and yeast extract produced maximum amylase.
Sujets)
Amylases/composition chimique , Bacillus/enzymologie , Biotechnologie/méthodes , Carbone/composition chimique , Industrie alimentaire/méthodes , Concentration en ions d'hydrogène , Déchets industriels , Industrie , Oligosaccharides/composition chimique , Amidon , Température , alpha-Amylases/métabolismeRésumé
Effect of the polycation on oxidative phosphorylation in the rat liver mitochondria has been studied. Both oxygen uptake and coupled phosphorylation were progressively inhibited by increasing concentration of the polycation, as observed with NAD-linked substrates, succinate and ascorbate+TMPD which activates the terminal part of the respiratory chain. NADH oxidase, NADH dehydrogenase and cytochrome oxidase were strongly inhibited by the polycation, 80-90% of the activity being lost at an inhibitor concentration of 100 microM. Succinate oxidase and succinate dehydrogenase were inhibited 60-66% at 100 microM concentration of the polycation. The polycation inhibited the uncoupler 2,4-dinitrophenol stimulated ATPase activity both in presence and absence of Mg2+ ions. The polycation also inhibited salt-induced volume change.
Sujets)
Animaux , Transport d'électrons/effets des médicaments et des substances chimiques , Mâle , Mitochondries du foie/effets des médicaments et des substances chimiques , NAD/métabolisme , Phosphorylation oxydative/effets des médicaments et des substances chimiques , Polyamines , Polymères/pharmacologie , RatsSujets)
Animaux , Bovins , ADN , Dénaturation d'acide nucléique , Polyamines , Polymères , Thymus (glande)Résumé
A novel polycationic ionen was synthesized and fractionated on carboxymethyl- Sephadex using a salt gradient in 7M urea. A series of oligomers of discrete length were characterised by ultraviolet spectra. The ultraviolet spectra of oligomers revealed a new band centred at 232.5 nm which was probably due to exciton splitting. Thermal denaturation studies indicated both stabilization of the helix conformation and a higher degree of cooperativity in the melting of DNA (oligomers)n complex as compared to native calf thymus DNA. Ionen oligomers exhibited large extrinsic Cotton effect at 232.5 nm which could be attributed to exciton interaction.