Isozymes of <Emphasis Type="Italic">α</Emphasis>-amylases from newly isolated <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> CKB19: Production from immobilized cells

The aim of this study was to produce two isozymes of α-amylase by immobilization of a newly isolated soil bacterium. The bacterium was identified as Bacillus thuringiensis CKB19 on the basis of its 16S rRNA profile. Enzyme production by free cells increased linearly with cell growth up to 34 h in starch containing enriched liquid media. The active bacterial cells were immobilized in Caalginate beads, and operational stability of the entrapped cell was optimized for amylase production. Enzyme production was optimal at an alginate concentration of 2 g% (w/v), calcium chloride concentration of 1 M, and with 300 beads (each bead contained 2 × 10⁷ cells)/250 mL flask. Amylase production by the immobilized cells was about 3 times higher than free cell fermentation after 34 h of incubation. It was observed that the immobilized bacterium secreted two different amylases (Am-I and Am-II) into the culture fluid. The molecular masses of Am-I and Am-II were 59.6 and 44.7 kd, respectively, and showed optimum activity at pH 5.0 and 9.0. Both amylases showed optimum activity at 40°C and were stable at the same temperature, with losses of only 10 and 20% (for Am I and Am II, respectively) of their original activities after 24 h of incubation. Further, both amylases were salt tolerant (up to 4 M NaCl) and hydrolyzed raw starchy foods into glucose. All these characteristics make this enzyme mixture suitable for use as a digestive aid and for the improvement of digestibility of animal feed ingredients.     

Biological characteristics of the peptides α and β isolated from bovine seminal plasma

The bull seminal plasma peptides α andβ have been examined for their biological properties. While both the peptides were able to inhibit the human chorionic gonadotropin-dependent uterine response in the mouse, α alone exhibits the property of suppressing post-castrational rise in gonadotropin in appropriate animal models. This suggests that the peptideβ must be acting directly on the ovary to suppress estrogen production and, consequently, the uterine weight increase. Such a possibility was confirmed when α andβ were examined by the coupled bioassay which is capable of discriminating between pituitary feedback factors and those acting directly on the gonad. In a test system designed to examine chronic effects, both α andβ showed evidence of acting directly on the ovary to inhibit human menopausal gonadotropin-induced estrogen production. Such a direct action could not be correlated with the relative potencies of these peptides when examined for their follicle stimulating hormone-receptor binding inhibitor and lutinizing hormone-receptor binding inhibitor activities.     

Molecular Mapping and Character Tagging in Mustard (Brassica juncea) II. Association of RFLP markers with Seed Coat Colour and Quantitative Traits

In Brassica juncea, segregation of 44 RFLP markers generated by homologous genomic DNA clones as probes was studied in a F₂ population obtained from an intervarietal cross. Linkage relationship among the markers was established using computer package ‘MAPMAKER’. Twenty five of the markers could be arranged in nine linkage groups, covering a total of 243.3 cM. Marker BJG357c showed tight linkage (3.9 cM) with yellow seed coat colour locus (r ₁). Based on single factor analysis of variance,17 significant marker-trait associations could be established in respect of six quantitative traits viz. days to flowering, plant height, number of primary branches, secondary branches per primary branch, siliquea per secondary branch, and seeds per siliqua. The proportion of phenotypic variation explained by individual marker-trait association ranged from 3.0% to 33.2%. The putative gene action at majority of the marked genomic regions was found to be partial dominance to dominance.