Comparative study of the effect of L-lysine-L-oxidase from Trichoderma harzianum Rifai and Trichoderma viride on nucleic acid synthesis in human tumor cells in vitro

L-lysine-alpha-oxidase, a new fungal enzyme catalyzing oxidative deamination of L-lysine, exerts an inhibitory effect on DNA, RNA and protein synthesis in human cells of carcinoma ovarius (CaOv) in vitro.     

Mutagenic effect of mitomycin C on different strains of oleandomycin producer Streptomyces antibioticus

Mitomycin C, a DNA-tropic antibiotic, was shown to have a lethal effect on spore sprouts of two strains of Streptomyces antibioticus, an organism producing oleandomycin. When the time of exposure to the antibiotic increased there was an almost equal decrease in the survival rate. The mutagen action on the morphological variation and antibiotic production of the two closely related strains were diverse due to their genetic differences. The strain isolated after the culture treatment with a chemical mutagen and subjected to a more prolonged maintaining selection showed lower variation with respect to its colony morphology. The other strain isolated after treatment of the culture with high concentrations of its own antibiotic showed lower variation with respect to its antibiotic production property. The shift in the antibiotic production in the direction of the low active variants was characteristic of the both highly productive strains.     

Complementary-addressed elimination of E1a sequence of simian adenovirus oncogene SA7 from circular single-stranded DNA of recombinant phage M13

The G fragment of the simian adenovirus SA7 oncogene corresponding to E1a region was cloned into M13mp8 and M13mp9 phages. Single-stranded DNAs of the recombinant phages thus obtained (mp8G and mp9G) partially digested with DNAse II were used to synthesize polyalkylating derivatives capable of specific hybridisation and subsequent alkylation of complementary G sequences of corresponding phage DNAs. After incubation of complementary alkylated DNA in the presence of lysine, the preselected region (G fragment) was specifically eliminated without damaging vector sequences. The method of complementary-addressed cleavage proved to be useful for precise analysis of reactions of polyalkylating derivatives within complementary complexes.     

Subcloning of DNA fragments of the simian adenovirus SA7 oncogene in bacteriophage M13

The XmaI/PstI and XmaI DNA fragments of adenovirus SA7 oncogene and the adjacent region (16.7% of the physical map of SA7 left end DNA) were recloned in M13 bacteriophages mp8 and mp9 in order to obtain the singlestranded fragments EIa and EIb from the DNA region of monkey adenovirus SA7 located on the recombinant plasmid pASP carrying the DNA APstI fragment including the adenovirus SA7 oncogene.     

Comparative study of different variants of Actinomyces roseoflavus producing the polyene antibiotic roseofungin

The respiration chain in the membranes of whole Actinomyces roseoflavus (var. roseofungini) cells from the parent and secondary cultures is sensitive to KCN, non-sensitive to Triton X-100 treatment removing the antibiotic roseofungin from the cells, and has a very high for the bacteria respiration control. When the cells are in contact with atomic tritium at the temperature of liquid nitrogen, roseofungin is tritiated and binds to A. roseoflavus isolated membranes and whole cells, mostly to those of the parent culture as compared to the secondary culture. A fraction of membranes which lost NADH dehydrogenase in the course++ of purification was isolated from the cells disintegrated in the frozen state.     

Effect of heparin on the antiradiation activity of cystamine, decreasing with a reduction in radiation intensity

It was shown that a single injection of heparin (250 units/kg) 15 min and 24 h before irradiation potentiated a slight radioprotective effect of cystamine (dichlorohydrate, 170 mg/kg) which was registered after the administration thereof to mice 30 min before irradiation with an absolutely lethal dose at a dose rate of 0.0025 Gy/c.     

Lethal and mutagenic action of N-nitroso-N-methylbiuret on the producers of levorin, amphotericin and mycoheptin]

The lethal and mutagenic effect of N-nitrozo-N-methylbiuret (NMB) on the organisms producing levorin, amphotericin B and mycoheptin was studied. The mutagen effect depended on the dose, culture and physiological state of the spores. NMB had a low mutagenic effect on the levorin-producing organism characterized by high activity and genetic homogenicity with respect to the colony morphology and antibiotic production. As for the organisms producing amphotericin B and mycoheptin characterized by high genetic heterogenicity, significant variation of all the features studied was observed on their exposure to the mutagen. Inspite of diverse reaction of the organisms producing levorin, amphotericin B and mycoheptin to the effect of NMB mutants with increased antibiotic production were obtained from the three cultures. The lethal and mutagenic effect of NMB on the mycoheptin-producing organism depended on the process of the spore DNA replication. The spores during the DNA replication period were least sensitive to the lethal effect of the mutagen and most mutable with the respect to the colony morphology. For selection of highly active and stable strains exposure to NMB of the spores of the mycoheptin-producing organism during replication of DNA proved to be more effective than that of the spores during the lag-phase.