Purification and characterization of pyocins from Pseudomonas aeruginosa.

Three types of pyocins were found in Pseudomonas aeruginosa strain 986 and named pyocin type P25, P50, and P70. Production of these types was inducible by UV irradiation. Their molar mass was estimated. The pyocins obtained were different from the known pyocins R, S, and F in their chemical and physical properties. No immunological cross reaction was observed among these pyocins.

Comparative diagnostic study of kala azar.

Sera from 58 children with hepatosplenomegaly were tested for kala azar by gel diffusion immunoelectrophoresis, countercurrent immunoelectrophoresis and micro-ELISA. The results are compared with those from bone marrow cultures: 40 cases were diagnosed as kala azar by the four immunological techniques and Leishmania parasites were grown in 37 of 40 bone marrow cultures. The techniques used are discussed in terms of sensitivity, specificity and simplicity. The micro-ELISA technique was the most sensitive and convenient to carry out and is strongly recommended for use in routine diagnosis and epidermiological surveys.

Kinetics of IMP:NAD+ oxidoreductase in serum of normal Iraqi individuals.

The general kinetic parameters of IMP:NAD+ oxidoreductase, were investigated at 37 degrees C in normal human serum. These included substrate - velocity relationship, Km (IMP), Km (NAD), as well as the effect of temperature and pH on the kinetics of the reaction. Optimum conditions of IMP, NAD+ oxidoreductase in serum of normal Iraqi individuals at 37 degrees C were investigated. The optimum IMP concentration was found to be 0.6166 mM and the optimum NAD+ concentration was 6.28 mM, while the optimum pH for the reaction was found to be 8.3. The enzyme shows low stability even when the sera were incubated at low temperature. The activity of the enzyme is proportional to the serum concentration and its optimal temperature for the reaction was 37 degrees C. The enzyme was found to be inhibited by XMP, GMP competitively with Ki values of 0.0724 mM and 0.1583 mM respectively. The inhibition by thyroid hormone (T4) was studied giving a Ki value of 2.25 X 10(-6) mM. The mechanism of enzyme action was found to follow ordered sequential mechanism.

Isoenzyme characterization of Leishmania species from Iraq.

Leishmaniasis in Iraq takes both the visceral and cutaneous forms. The causative organisms are identified according to the electrophoretic variation of the enzymes MDH, GPI, 6PGD, PGM and IDH. The 37 visceral stocks investigated fall into two groups which differ only with respect to GPI. The six cutaneous stocks were divided into three groups. Group 3 represents Leishmania major, while groups 4 and 5 refer to L. tropica showing intraspecific variation with regard to 6PGD.

The primary isolation of Leishmania donovani from Iraq on different culture media.

Leishmania donovani was isolated by culturing bone marrow aspirates from kala-azar patients, on three types of culture media. The isolation was successful in 88% of the cases. The effects of pH, D-glucose, L-proline and antibiotic concentration in the isolation were investigated. The semi-solid medium used (pH 7.4) with L-proline, was better than the modified NNN media for the primary isolation.

Characterization of the multiple forms of monoamine oxidase from chronic schizophrenic sera.

Either half or one hour incubation time was enough to get a constant production of benzylaldehyde and were proportional to the amount of enzyme added. The optimal temperature of MAO, I, II, III, IV are 60 degrees, 37 degrees, 60 degrees, 45 degrees, and 37 degrees C respectively, and they follow Arrhenius equation until these optimal temperatures. Each form have optimal pH depends on substrate concentration used and the buffer used. These forms were shown to be inhibited by high substrate concentration with formation of inactive enzyme-amine complex, whereas butyl- and octylamine was found to be competitive inhibitors. Isoniazid inhibit MAO II, III, IV and V forms in a non competitive fashion, whereas MAO I inhibited competitively with respect to the substrate. Semicarbazid inhibit MAO I. III, IV and V forms in a non competitive fashion, whereas MAO II inhibited competitively with respect to the substrate.

Multiple forms of monoamine oxidase in chronic schizophrenia.

Reduced monoamine oxidase was found in the sera of fourty five schizophrenic patients with enzyme level (10 units), only five of these patients show enzyme level identical with minimum range of normal controls. Michaelis constants of schizophrenic patients show great difference from that of the normal controls. Our result suggests that schizophrenic patients possess a qualitatively different monoamine oxidase with an altered molecular structure. Four and five multiple forms were found in sera of normal human and schizophrenic patients respectively, using sepharose 6B, indicated that these different forms were of different molecular weight. Each multiple form is identified by cellulose acetate electrophoresis as they attached to different fraction of serum proteins.

Kinetics of lactate dehydrogenase and other enzyme studies in human serum in leukemia.

The activity of some of the clinically important enzymes was investigated in leukemic sera at 37 degrees, using the Beckman Enzyme Activity Analyzer were found to be slightly elevated in some untreated cases of leukemia (1.), while ALP was found to be frequently elevated. Untreated patients with l. had normal or below normal SCPK activity. The most characteristic and significant rise in activity, was found to be associated with SLDH and SHBDH in most cases of acute l. (86%) and in CML, while any elevation observed in CLL, was very slight. The general kinetic parameters of SLDH and SHBDH, were investigated at 37 degrees in acute leukemic patients. These included optimum substrate concentrations (NADH, pyruvate, and 2-oxobutyrate), the rate of pyruvate and 2-oxobutyrate reduction, substrate-velocity relationship, Km (pyruvate), Km (NADH), Km (2-oxobutyrate) as well as the effect of temperature and pH on the kinetics of the reaction. These kinetic characteristics were found to be differently affected by the leukemic process.

Further studies on lactate dehydrogenase from serum of leukemic individuals.

The kinetic properties of SLDH were investigated in untreated patients with acute leukemia at 37 degrees. SLDH was found to be inhibited by high pyruvate concentrations to a degree which depended on the pH of the reaction mixture; the degree of inhibition of normal SLDH at pH 7.5 was much higher than leukemic SLDH. 0.4M citrate was found to activate SLDH reaction rate at low pyruvate concentrations, while it was inhibitory at high pyruvate concentrations; the degree of inhibition being greater for leukemic SLDH than for normal SLDH. Citrate was also found to be a non-competitive inhibitor with respect to NADH and the value of Ki was determined. Methanol (3-4M), acted as a strong inhibitor to SLDH. The inhibition was found to be purely non-competitive with respect to pyruvate. Ki was calculated to be four times higher for leukemic SLDH than for normal SLDH.

Further studies on 5'-Nucleotidase from serum of liver cirrhotic individuals.

The kinetic properties of 5'-Nucleotidase were investigated in untreated patients with liver cirrhosis at 37 degrees C. Mg+2 and Mn+2 were found to activate both normal and liver cirrhotic 5'-Nucleotidase, but Nickel inhibited the enzyme in both systems competitively. Both ATP and adenosine act as inhibitors to 5'-Nucleotidase. The inhibitory constant for ATP was different in normal and liver cirrhotic individuals, 0.1 +/- 0.03 for normal and 0.225 +/- 0.02 for liver cirrhosis. In our investigation, ATP was found to be a competitive inhibitor of 5'-Nucleotidase which compete the substrate (A-5'-MP) for the active site. Inhibition of 5'-Nucleotidase by adenosine is of non-competitive type, for both normal and liver cirrhotic sera. It was observed that both serum 5'-Nucleotidase exhibited pH dependent characteristics; in that there was an optimum substrate concentration at each pH value and the plot of pKm versus pH shows great dependency of km on pH.

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.