Role of metal ions in goat carboxypeptidase A-catalysed hydrolysis of acyl peptides

The carboxypeptidase A purified from goat pancreas has been found to have a molecular weight of 34,600 +/- 300. The enzyme is a zinc-protein and the molar ratio of zinc to enzyme protein is 1:1. Removal of zinc yields an inactive apocarboxypeptidase A. The loss of activity of the native enzyme and restoration of the activity of the apoenzyme run parallel with the zinc content of the protein, thus showing the essentiality of zinc for the enzymatic activity. The exact role of zinc in the enzyme catalysed hydrolysis of the acylpeptides has been investigated after preparing metallo proteins by substituting the zinc of carboxypeptidase A with Co2+, Mn2+, Ni2+, Fe2+, Cd2+, Hg2+, and Cu2+ and determining the kinetic parameters of such metalloproteins. These studies indicate that the metal ion is involved in both binding the substrate and polarising the peptide bond.

Differential responses of sunflower (Helianthus annuus cv. Modern) towards high and low concentrations of dikegulac sodium

In pot experiments, foliar application of dikegulac sodium (2,3:4-6-di-O-isopropylidene-α-L-xylo-2-hexalofuranosate) at 500 and 750 μg/mL inhibited plant growth and decreased growth and dry matter production of the treated leaves of sunflower (Helianthus annuus L. cv. Modern). A concentration of 100 μg/mL, however, increased leaf area and anabolic activities of treated leaves. Increased cambial activity was noted at all concentrations of dikegulac, which resulted in formation of secondary tissues. At 500 and 750 μg/mL RNase and protease activities increased appreciably, while catalase activity was drastically suppressed. The inhibitory effect of dikegulac was also found in newly expanding leaves which developed after treatment. Beneficial effects of dikegulac at low concentration were also reflected in field experiments where increased yield was noted, while high concentrations were distinctly inhibitory. The importance of dikegulac as an agronomically promising chemical for sunflower is discussed.

Polyarthritis with atypical keratotic nodular dermatosis or polyarthritis with multiple keratoacanthoma. A case report

We report an interesting case of generalized papular and nodular lesions with central keratinous plugs and severe hyperkeratotic-acanthotic histopathology with arthritis in a 19-year-old male patient who had suffered from a similar disease 2 years earlier. Papules and nodules erupted a few days after the arthritis and this was noticed during both episodes. On healing, nodules fell spontaneously leaving behind insignificant hyperpigmented scars.

Studies on synthesis and uptake of taurine in rat lens in vitro

The occurrence of large taurine pool sizes in the crystalline lens was further elucidated by studying the in vitro synthesis and uptake of taurine in the rat lens. It was observed that a time- and concentration-dependent synthesis of taurine from methionine occurred in the rat lens. The time curve for uptake was linear up to 4 hr and was not saturated up to 40 mM concentration of taurine. The uptake was inhibited by ouabain, cyanide, Ca2+, GTP and cGMP but was not affected by ATP and cAMP. It is suggested that a dual mechanism exists for maintenance of high concentrations of taurine in the lens. Moreover, the uptake mechanism is energy-dependent.

Distribution of taurine in the crystalline lens of vertebrate species and in cataractogenesis

Marked heterogeneity was observed in the distribution of taurine in different regions of the lens in various species. In general low taurine pools were observed in the nucleus of all species except frog and human. The distribution of taurine in human senile cataractous lenses at different stages of maturation showed decreased contents in all the regions except capsule epithelium as compared to the normal human lenses. This decrease is progressive upto the 'mature' stage of cataract. In rat lenses with galactose cataracts taurine contents decreased by about 83-94% of the normal values in the equatorial, anterior, posterior cortical and nuclear regions.

An immunofluorescence study of anti-pancreatic islet cell antibodies in the spontaneously diabetic BB Wistar rat

Sera from BB Wistar rats and Wistar control rats were evaluated for the presence of islet cell antibodies in a prospective study using an indirect immunofluorescence assay on pancreatic islet cell suspensions from cultured rat islets. Islet cell surface antibodies were detected in sera from all animals of the spontaneously diabetic BB Wistar rat colony. The antibody could be detected well before the clinical onset of the disease and was present throughout the course of study of all diabetic animals. Sera from control Wistar rats were negative when tested for this antibody.

Strain and sex differences in serum alpha-fetoprotein levels in Mus musculus

Normal levels of circulating serum alpha-fetoprotein (AFP) in different inbred strains of mice, as determined by radioimmunoassay, are reported. These strains show different and characteristic values for the mean serum AFP concentration, suggesting genetic control of the serum level of this protein. Furthermore, within each strain a difference in serum levels of the protein is observed between sexes; males have a significantly higher serum AFP concentration.