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V N Soĭfer

Publications and source records attributed to V N Soĭfer.

17 recordsLinked to original sources
PubMed1979

[Effect of pancreatic DNAse on DNA synthesis in Bacillus subtilis].

An addition of pancreatic DNAse to the cultural medium is found to stimulate DNA synthesis and proliferation of Bacillus subtilis cells. Pancreatic DNAse induces a single-stranded disruption of Bac. subtilis DNA, which may act as a mechanism of DNA synthesis increase and of the culture growth acceleration.

Bacillus subtilis↗
PubMedDate not supplied

[Genetic change in the waxy trait of barley under the influence of wild type DNA. Analysis of the composition of starch and the electrophoretic spectrum of caryopsis hordein from altered plants and the retention of these changes to the fourth generation].

Injection of DNA isolated from the wild type of barley into grains of recipient mutant plants (waxy mutants) at the milk stage of maturity leads to a change in starch synthesis; type of spikes and hordein composition. In the first generation of injected plants the wild type starch synthesis was observed in some separate plants (these observations were made at a haploid level in pollen cells). In the second generation of transformed plants along with the change in starch and hordein synthesis a modification of the type of spikes was also revealed. Recipient plants had six-rowded (hexastichous) spikes, and donor plants--two rowded (distichous) spikes. Disc-electrophoresis of hordeins of the wild type barley (Yuzhny var.), hordeins of the waxy mutant (defected in synthesis of normal starch) and barley plants transformed under the action of wild type exogenous DNA reveals differences in the protein spectrum between donor, recipient and transformants. In the second generation in many of the transformed plants starch synthesis reverted to the recipient mutant type. Simultaneously a reversion of hordein composition to the initial mutant type was observed, and the distichous pikes became hexastichous. Analysis of the components of starch revealed that donor plant that have amilose and amilopectin in starch, and the recipient plants that lack amilose, can be distinguished by the spectra of light absorption of starch. For characterizing these differences the plot of absoprtions at 490 versus that at 590 nm was used. The tangens of angles of these curves for the waxy mutant were equal to 1.05 +/- 0.07 and 1.81 +/- 0.04 for the wild type barley. All transformants have a 1.78 ratio and for revertants this value was 1.02.

DNA↗
PubMedDate not supplied

[Mutagenesis of synchronous populations of Escherichia coli with normal and defective reparative enzymes under the influence of hydroxylamine].

Bacterial populations of E. coli K12 uvr+ and E. coli K12 uvr- were preliminary synchronized on membrane nitrocellulose filtres and then treated with 1 M hydroxylamine for different times; the frequency of mutants failing to assimilate glucose was estimated. Kinetics of mutagenesis in the cells of both strains was almost the same and indicated that lesions induced by hydroxylamine were not repaired. It is for the first time that the maximum mutation frequency was registered in experiments with hydroxylamine; this suggests that the repair hypothesis of attaining the maximum mutation frequency is not universal.

Escherichia coli↗