Kinetics of 5--nucleotidase in sera of liver cirrhotic and normal Iraqi individuals.

5'-Nucleotidase activity was elevated in patients with liver cirrhosis; greater values of 5'-Nucleotidase activity were found in biliary cirrhosis, 5'-Nucleotidase from liver cirrhotic sera was less stable than from normal sera. The velocity of 5'Nucleotidase from liver cirrhotic sera per minute, at t = 10, was greater than normal controls. The optimum (S) for 5'-Nucleotidase was found to be 1.0 mM A-5'-MP, for both normal and liver cirrhotic sera. Km (A-5'-MP) and (2'-d-A-5'-MP) of 5'-Nucleotidase was found to be significantly lower in patients with liver cirrhosis than normal controls.     

Heterologous transformation in Bacillus subtilis. 1. Transmission of DNA of the R1drd19 plasmid]

Bac. subtilis 168 (BD-25) cells were infected with DNA of plasmide R1drd19 isolated from E. coli strain; transformants resistant to streptomycin (500 microgram/ml) and kanamycin (40 microgram/ml) appeared with the frequency of 2.10(-6). These transformants retained resistance to the mentioned antibiotics stably. A satellite DNA peak was revealed in centrifugation in the density gradient of cesium chloride with ethidium bromide. It was possible to infect cells of Bac. subtilis 168 (BD-25) with plasmide DNA isolated from the transformants. Plasmide transduction with the aid of phages AR9 and PBSI multiplied on the transformant strains was also effected. Physico-chemical analysis of the transformed plasmide DNA was conducted; its molecular weight was determined.     

Effect of vitamin B6 on gamma-aminobutyric acid level in rat brain.

Vitamin B6 injected intraperitoneally into rats 400 mg/kg body weight, has produced a statistically significant decrease in GABA level concentrations in hippocampus and cerebellum. Cerebral cortex, caudate nucleus and thalamus have shown the decrease in GABA concentrations, but these changes were not statistically significant. No remarkable behavioural changes were noted under such circumstances. The possible functional meaning of these results is discussed in relation to the role of GABA distribution in different brain regions and development of convulsions.     

Tissue and serum TPA in subjects at risk for bladder cancer

We tested the presence of tumour polypeptide antigen (TPA) in lower urinary tract cells from 59 workers exposed to known bladder carcinogens and from 30 control subjects. We then correlated immunocytological expression and serum TPA levels. Lower urinary tract cells from 31 subjects gave either moderately or strongly positive immunocytological stains. Five also had high serum TPA. The detection of TPA by cytology and in serum differed significantly in workers exposed to cancer agents and the control group.     

A new species of Eriocaulon (Eriocaulaceae) from Madhya Pradesh, India

Eriocaulon raipurense (Eriocaulaceae) is described and illustrated as a new species from Madhya Pradesh, India. The species is closely allied to E. hamiltonianum but differs in the size and apex of involucral bancts, white-pilose nature of floral bracts and colour of female petals.     

Studies on the formation and stability of a complex between Streptomyces proteinaceous metalloprotease inhibitor and thermolysin.

The effects of certain physicochemical parameters on the formation and stability of a complex between Streptomyces proteinaceous metalloprotease inhibitor (SMPI) and thermolysin were investigated. SMPI had its lowest Ki value at a pH of around 6.5 (similar to the pH dependence of the kcat/K(m) of thermolysin catalysis), reflecting the splitting mechanism of the SMPI inhibition of thermolysin. This Ki increased with an increase in pressure, and in (Ki-1) was almost linear with respect to pressure. The volume of the reaction (delta Vcomp), which is the volume change accompanying enzyme-inhibitor complex formation, was calculated as +8.1 +/- 0.3 mL.mol-1, which has a sign opposite to delta Vcomp for neutral peptide inhibitors and acyl-peptide substrates. The temperature dependence of Ki-1 gave the reaction enthalpy (delta Hcomp) and reaction entropy (delta Scomp) of the complex formation as 34.6 +/- 1.4 kJ.mol-1 and 298 +/- 5 J.mol-1.K-1, respectively. These positive reaction volumes and reaction entropies were related to the electrostatic interactions and ionic strength dependence of Ki which corresponded to the key ionic interaction during complex formation. Complex formation with SMPI stabilized thermolysin against pressure perturbation as observed by the changes in the Trp fluorescence of thermolysin with increasing pressure. Thermal stability, however, was affected very little by complex formation with SMPI. Phosphoramidon, Cbz-Phe-Gly-NH2 and Cbz-Phe also positively affected the pressure-tolerance of thermolysin, in the following order: Cbz-Gly-Phe-NH2 < Cbz-Phe < phosphoramidon. The third compound exhibited stabilizing effects comparable with those of SMPI, which suggests that the interaction between SMPI and thermolysin was localized to the reactive site.