Browsing by Author "Nandi, R"
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Item Circular dichroic determination of DNA base composition.(1987-04-01) Maiti, M; Nandi, RItem Effect of berberine chloride binding on the structure of cholera phage phi 2 DNA.(1983-08-01) Chaudhuri, K; Nandi, R; Maiti, MItem Effect of various organic compounds on synthesis of glucoamylase by an isolated strain Penicillium italicum.(1989-12-01) Nandi, R; Mukherjee, S KYeast extract (0.5%) stimulates the production of glucoamylase and cell synthesis while methylene blue (0.1 mM) activates the synthesis of glucoamylase. Studies on the metabolic changes during fermentation of glucoamylase in a selected medium by P. italicum show that the rate of production of glucoamylase and cellular growth are greatly accelerated between 48 and 168 hr. Rapid growth of cells during this period may account for enhanced utilization of maltose and NH4NO3 from the medium. The acid production remains constant from 48 to 144 hr. Different forms of nitrogen decrease steadily. Although methylene blue stimulates the production of glucoamylase in the broth it has practically no effect on the rate of utilization of amino and total nitrogen from the broth.Item Interaction of berberine chloride with deoxyribonucleic acids: evidence for base and sequence specificity.(1989-08-01) Debnath, D; Kumar, G S; Nandi, R; Maiti, MThe interaction of berberine chloride with natural and synthetic DNAs of differing base composition and sequences was followed by various spectroscopic and viscometric studies. The binding of berberine chloride was characterized by hypochromism and bathochromism in the absorption bands, enhancement of fluorescence intensity, stabilization against thermal denaturation, perturbations in the circular dichroic spectrum, increase in the contour length of sonicated rod-like DNA and induction of unwinding-rewinding process of covalently closed superhelical DNA, depending on the base composition and sequences of base pairs. Binding parameters determined from absorbance and fluorescence titration by Scatchard analysis, according to an excluded-site model, indicated a very high specificity of berberine to AT-rich DNAs and alternate AT polymer. Fluorescence quantum yield was maximum for the complexes with AT-rich DNAs and alternate AT polymer. Taken together, these results suggest that berberine chloride exhibits considerable specificity towards alternating AT polymer and binds to AT-rich DNAs by a mechanism of classical intercalation.Item Interaction of sanguinarine with natural and synthetic deoxyribonucleic acids.(1984-06-01) Maiti, M; Nandi, R; Chaudhuri, KItem pH induced change of natural deoxyribonucleic acids as followed by circular dichroism.(1986-12-01) Maiti, M; Nandi, R