http://192.168.1.40:8080/xmlui/handle/123456789/1350 2026-05-31T13:43:54Z http://192.168.1.40:8080/xmlui/handle/123456789/2446 Symbiotic effectiveness of a siderophore overproducing mutant of Mesorhizobium ciceri. Raychaudhuri, N.; Das, S. K.; Chakrabartty, Pran Krishna Mutants of Mesorhizobium ciceri BICC 651 were generated by N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis. Siderophore overproducing mutants were identified on Chrome azurol S agar plates. One of them determined as N15 was examined for symbiotic efficiency and compared to its wild type parent i.e. BICC 651 strain under sterile conditions using Leonard jars in growth chamber and also in pots containing nonsterile alluvial field soil. It was observed that the strain N15 produced about 30% higher number of nodules per plant, fixed 25% more nitrogen per gram of nodule and caused more than 30% increased dry weight of plant shoots. 2005-01-01T00:00:00Z http://192.168.1.40:8080/xmlui/handle/123456789/2441 Deterioration of soil physicochemical properties, microbial biomass C, and N-mineralization due to replacement of sal forest with exotic species and rain-fed agriculture in East India Roy, S.; Chakrabartty, Pran Krishna Effects of conversion of natural forest dominated by Shorea robusta, supported on old alluvial soil, to exotic Eucalyptus tereticornis or Acacia auriculiformis plantation or to agricultural field for cultivation of rice, have been examined in respect of soil microbial biomass C, N and N-mineralization. Mean annual microbial C and N, respectively were 702 μg g -1 and 85 μg g -1 in the Shorea forest, 678 μg g -1 and 89 μg g -1 in the Acacia plantation, 627 μg g -1 and 73 μg g -1 in the Eucalyptus plantation and 349 μg g -1 and 60 μg g -1 in the cropland. Highest biomass was manifested during the summer and lowest in the rainy season in all the sites examined. Peak N-mineralization was obtained during the rainy season in the following order - the Shorea forest > the Acacia plantation > the Eucalyptus plantation > cropland. Thus, the Eucalyptus plantation appears to have lower soil microbial activity than the Shorea forest as well as the Acacia plantation. The control of microbial C and N on N-mineralization was maximum in the Shorea forest and minimum in the Eucalyptus plantation although correlation between microbial N and N-mineralization was insignificant in the Acacia plantation (may be due to localized chance fluctuations). Tendency to immobilize nutrients was maximum in the Eucalyptus plantation as evidenced by the low release of nutrients from microbial biomass during the rainy season. It was found that the Eucalyptus plantation soil was microbially more inert in terms of nutrient release from soil biomass and N-mineralization than that of the Acacia plantation as well as the natural Shorea forest. However, any type of exotic species plantation as well as agriculture have adversely and significantly affected the micro biota mediated soil fertility fabrication of the natural Shorea forest milieu. 2004-03-01T00:00:00Z http://192.168.1.40:8080/xmlui/handle/123456789/2393 Production and characterization of nisin-like peptide produced by a strain of Lactococcus lactis isolated from fermented milk Mitra, S.; Chakrabartty, Pran Krishna; Biswas, S. R. An isolate of Lactococcus lactis from fermented milk was found to produce a bacteriocin peptide. The isolate could grow in a medium with an initial pH of 11.0, in which it produced the bacteriocin extracellularly at the highest level. The level of the bacteriocin in the medium increased in parallel to the bacterial growth and reached its peak during the late exponential phase; thereafter it plateaued. The bacteriocin had a broad antibacterial spectrum similar to that of nisin and inhibited several related species of lactic acid bacteria and other Gram-positive bacteria. The inhibitory activity of the bacteriocin was found to be stable over a wide range of pH and temperature. The molecular weight of the peptide was judged to be 2.5 kDa by SDS-polyacrylamide gel electrophoresis. DOI: 10.1007/s00284-005-4545-2 2005-09-01T00:00:00Z http://192.168.1.40:8080/xmlui/handle/123456789/2385 An extracellular protease with depilation activity from Streptomyces nogalator Mitra, P.; Chakrabartty, Pran Krishna An extracellular protease-producing actinomycete, Streptomyces nogalator strain Ac 80, was isolated from soil. Mutants of the strain designated as Mt C producing protease of higher (3.0 mg tyrosine liberated/min/mg protein) and Mt L of lower (0.9 mg tyrosine liberated/min/mg protein) specific activity as compared to that of the wild type (1.8 mg tyrosine liberated/min/mg protein) were selected. Proteolytic activity of the wild type and the mutants correlated with their depilation capacities. Proteolytic enzyme produced by Mt C in solid state fermentation was purified to homogeneity, and partially characterized (molecular mass, 66 kDa by SDS- PAGE). It was found to be efficient in depilation of goatskin. 2005-12-01T00:00:00Z