Volume 1, Issue 3
September 1979, pages 255-355
pp 255-261 September 1979
A method described for large scale cultivation ofEntamoeba histolytica axenically in a modified Diamond’s TP-S-1 monophasic medium. Crude amoebaantigen prepared by the ultrasonication of the trophozoites ofE. histolytica, was fractionated by sephadex G-200 column into four different fractions. The whole antigen and its different fractions were freeze-dried and upon reconstitution contained approximately 1.8 mg N/ml or roughly the equivalent of 10 × 106 amoebae per ml. Both whole antigen and its fractions have been used for the detection of specific antibody in the patients’ sera. Rabbits were immunised with the antigen and the immunoglobulins were separated from hyperimmune sera by DEAE-cellulose chromatography and salt fractionations. Sera collected from different categories of amoebiasis patients, amoebic liver abscess, amoebic hepatitis, amoebic dysentery, and asymptomatic amoebiasis, were tested serologically using standard amoeba-antigen for serodiagnosis and epidemiological assay of amoebiasis. Results of the assay showed that standard amoeba-antigen is very useful for diagnosis of invasive amoebiasis.
pp 263-269 September 1979
The production of L-asparaginase by two mutants ofSerratia marcescens grown on 14 different media was studied. The enzyme content increased from trace levels to 2.4 international units per ml when the organisms were grown in glycerol-peptone yeast extract medium. Glucose was the best carbon source under aerobic conditions. The enzyme content increased when L-asparagine was present in the growth medium.
pp 271-278 September 1979
Beta-exotoxin produced byBacillus thuringiensis var.thuringiensis grown in the acid hydrolysates of wheat and rice brans caused 95% and 85% mortality respectively ofMeloidogyne sp. as against 72% of β-exotoxin produced on farm yard manure within 7 days. Acid hydrolysate of wheat or rice bran and solid farm yard manure proved to be the best media for growth ofB. thuringiensis var.thuringiensis.
pp 279-287 September 1979
InNeurospora crassa,0.44 mM Be2+ caused half-maximal inhibition of growth and this inhibition could be fully counteracted by the addition of 2.5 mM Ca2+ to the medium. Mn2+ and Mg2+ were less effective in reversing the growth inhibition caused by Be2+ and the order of effectiveness was Ca2+ > Mn2+ > Mg2+. Fe3+ and Zn2+ were ineffective in reversing Be2+ toxicity.
Pyruvate, malate and succinate also reversed the growth inhibition caused by Be2+ inN. crassa. Pyruvate restored growth by a mechanism not involving control of Be2+ accumulation in the mould. The rate of utilisation of glucose by the mycelia grown in the presence of Be2+ was reduced, while that of pyruvate was not affected. The results indicate that the primary metabolic lesion in Be2+ toxicity inN. crassa is probably a block at some step(s) in the glycolytic sequence.
pp 289-293 September 1979
Thein vitro effect of δ9-tetrahydrocannabinol on adenosine triphosphatase and phosphodiesterase activities as well as on the cyclic-AMP content of human spermatozoa has been studied. At a concentration of 1.0 ▪g, sperm metabolism may be increased as shown by increased cyclic AMP and adenosine-triphosphatase activity while at a higher concentration (10 ▪g tetrahydrocannabinol), it may be reversed.
pp 295-304 September 1979
Lactic dehydrogenase fromLactobacillus casei ATCC 7469 has been purified to homogeneity by a two-step affinity chromatography procedure which gave an yield of 35%. The enzyme specifically catalysed the conversion of pyruvate to lactate. The enzyme was maximally active at pH 4.6, which was shifted to 5.4 in the presence of fructose 1,6-biphosphate. The enzyme had a molecular weight of 70,800 with two identical subunits, unlike the lactic dehydrogenase from other sources. Histidine and primary amino groups appeared to be involved in catalysis.
pp 307-316 September 1979
RNA extracted from purified rinderpest virus was characterised by sucrose gradient sedimentation and polyacrylamide gel electrophoresis. The predominant virion RNA species had a sedimentation constant of 46S and its estimated molecular weight was 4.8 × 106 daltons. Consistently high amounts of UMP and AMP were detected. The melting-temperature profile of the virion RNA suggested absence of secondary structure.
The effect of actionomycin D on the replication of rinderpest virus in Vero cells was studied by following the viral RNA synthesis using labelled uridine as well as by infectivity titration. The viral RNA synthesis was not affected until 12 h following infection and was inhibited thereafter between 18 and 48 h to an extent of 25% at 5 and 10 Μg levels of the drug. A 100 to 1000-fold reduction in the infectivity titres was observed in the presence of the drug. These results suggest that actinomycin D inhibits rinderpest viral RNA replication. Sedimentation analysis of viral RNA extracted from drug-treated cultures showed inhibition of the genome RNA of rinder-pest virus.
pp 317-326 September 1979
A preparation rich in the specific messenger RNA involved in the synthesis of prolactin from sheep anterior pituitary glands was obtained by employing both the immunochemical and affinity techniques. A dose-dependent and efficient stimulation of protein synthesis by the isolated total pituitary RNA as well as poly (A) rich RNA were achieved with the reticulocyte system. The synthesis of prolactin as one of the translational products of this cell-free system was established by specific immunoprecipitation followed by resolution on sodium dodecyl sulphate polyacrylamide gel electrophoresis.
pp 327-334 September 1979
Treatment ofTrigonella foenumgraeceum (fenugreek) seedlings with naphthalene acetic acid plus gibberellic acid enhanced the RNA synthesising capacity of nuclei isolated from the hypocotyl and cotyledonary regions. This increase was more pronounced in the nuclei from the hypocotyl region than from the cotyledonary region.In vitro addition of these phytohormones did not stimulate RNA synthesis by nuclei. The RNA synthesis by mitochondria was not affected by preincubating the seedlings with the hormones. The nuclei isolated from callus cultures of fenugreek hypocotyl treated with the hormone also showed increased RNA synthesis.
pp 335-343 September 1979
The rate of RNA synthesis and its inhibition by α-amanitin in the nuclei of mature and immature avian erythrocytes are increased with the increase in ionic strength of incubation medium. Polyacrylamide gel electrophoresis indicates that heterogeneous species of RNAs are synthesised in the mature and immature erythrocyte nuclei. However, a large number of high molecular weight RNAs are synthesised in the nuclei of immature erythrocytes. Elution profiles on poly(U)-sepharose chromatography indicate that the RNAs synthesised in the nuclei of two types of cell contain poly(A) segments. Sixteen per cent of mature erythrocyte nuclear RNA syntbesised are polyadenylated, while it is 13% in immature erythrocyte nuclei. However, the total RNA synthesised is 2–3 fold higher in immature erythrocyte nuclei than that in mature erythrocyte nuclei.
pp 345-354 September 1979
Four deletion plasmids, pHH301, pHH302, pHH303 and pHH401, obtained from RP1 DNA-transformed bacterial clones, were shown to be incompatible with three P plasmids inEscherichia coli K12 strains. Kinetic experiments and colony tests were used to verify the position of these R plasmids.Pseudomonas aeruginosa andE. coli strains, harbouring deletion plasmids, could be cured by using two mutagens, acriflavine and mitomycin C, which affect a percentage of the cell population. The deletion plasmid-positive strains could also be induced at an elevated temperature to spontaneously loose their plasmids.
pp 355-355 September 1979 Erratum