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V L Kalinin

Publications and source records attributed to V L Kalinin.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Escherichia coli K-12 mutants with enhanced resistance to ionizing radiation. IV. Recombination characteristics of Gamr mutants].

In the radiation-resistant Gamr444 mutant the inheritance frequency of long F' episomes ORF1 (purE+ tsx+ procC+ lac+) and F'14 (ilv+--argE+) is lower, and the frequencies of chromosome mobilization and integrative suppression of temperature-sensitive dnaA46 mutation by the sex factor F are much higher than those in the wild-type strain AB1157 and another radiation-resistant mutant Gamr445. In this respect, the mutant Gamr444 is very similar to the recRC sbcB mutant (RecF-pathway of recombination).

Chromosomes, Bacterial↗
PubMed1982

Induction of c-mutations in extracellular phage lambda by gamma-rays.

Mutagenic action of 60Co gamma-rays on extracellular phages lambda red1 and lambda red113 after irradiation in 4% nutrient broth in the absence or in the presence of 0.1 M cysteamine or in dried samples was studied. The yield of c mutations was almost independent of the repair genotype of the host cells (uvrA6, polA1, recA13, lexA102, uvrE502, uvrD3 or xthA9), of the phage Red function and of the conditions of gamma-irradiation and was 1 . 10(-12) per base pair and 1 rad. When the SOS-repair system of the host cells was induced by moderate UV irradiation, the yield of c-mutations was drastically enhanced in phage irradiated in broth, but not in phage irradiated in the dried state. These data allow us to suppose that the direct action of gamma-rays induces, in phage DNA, premutational lesions that are fixed into mutations by replication. On the other hand after gamma-irradiation in broth, when indirect radiation effects are only partially suppressed, about 85% of premutational lesions are converted into mutations by means of the inducible, errorprone SOS-repair system.

Bacteriophage lambda↗
PubMed1982

[Mutagenic action of nitrous acid on prophage lambda].

The lethal and mutagenic effects of nitrous acid (0,1 M NaNO2 in 0,1 M acetate buffer, pH 4.6) on prophage lambda cI857 ind- were studied in the wild-type cells of Escherichia coli and in 9 repair-deficient mutants: uvrA6, uvrA6 umuC36, uvrD3, uvrE502, polA1, recA13, lexA102, recF143 and xthA9. After treatment with HNO2, the prophage was heat-induced either immediately or after 90 min incubation in broth at 32 degrees C. The prophage survival after delayed induction was considerably higher than after immediate induction. The lethal action of HNO2 was highly expressed in uvrA- and uvrE- lysogens after delayed induction. The frequency of temperature-independent c mutants forming clear plaques at 32 degrees C reached 4% in the wild-type host after immediate induction, this value being 10-15% in uvrA, uvrA umuC, uvrD, uvrE, polA and xthA mutants, 0,8% in recF- lysogen and only 0,2-0,3% in recA and lexA mutants. Under these conditions, about 90% of c mutants are generated by recA+, lexA+-dependent repair mechanism (most probably, due to W-mutagenesis). After delayed induction, mutation frequency in the wild-type host declines considerably (down to 0,1%). Analogous phenomenon of mutation frequency decline was registered in uvrA, xthA, recF, polA, uvrE and uvrD lysogens. Under conditions of delayed induction, the frequency of HNO2-induced c mutations only slightly depends on the recA+ and lexA+ gene products and mutations are, apparently, fixed by replication.

Bacteriophage lambda↗
PubMed1982

[Escherichia coli K-12 mutants with enhanced resistance to ionizing radiation. II. Study of DNA damage and repair in gamma-irradiated cells].

Formation and repair of single-stranded breaks (ssb) and double-stranded breaks (dsb) in DNA of gamma-irradiated cells of three Escherichia coli strains (the parental strain AB1157 and radiation-resistant mutants Gamr444 and Gamr445) were studied by centrifugation in alkaline or neutral sucrose gradients. The initial yield of ssb and the kinetics of their repair during post-irradiation incubation in a growth medium are similar for Gamr mutants and the wild-type strain. The yield of dsb in the chromosome of Gamr mutants is significantly lower than in chromosomal DNA of the parental strain, both immediately after gamma-irradiation and after three hours of post-irradiation incubation in a growth medium. The decreased yield of dsb in the Gamr mutants correlates with their relative radioresistance. It was found also that the level of DNA degradation is significantly lower in UV- or gamma-irradiated cells of Gamr mutants, as compared with the wild-type strain. It is suggested that enhanced radioresistance of the Gamr mutants is due to decreased formation of enzymatically induced dsb, as a consequence of moderated DNA degradation under the action of repair exonucleases and also to enhanced efficiency of dsb repair.

DNA Repair↗
PubMed1980

W-mutagenesis in competent cells of Bacillus subtilis.

The relative yield (Nm/N) of fluorescent mutants Ind- after the transformation of Bacillus subtilis cells by means of UV-irradiated DNA is much higher in an uvr- recipient than in an uvr+ strain, when compared at equal fluence, but practically identical at equal survival. Ind- mutations are induced by UV-irradiation of separated single strands of transforming DNA. The H-strand is much more sensitive to the mutagenic action of UV light. Preliminary irradiation of competent recipient cells by moderate UV fluences increases the survival of UV- or gamma-irradiated transforming DNA (W-reactivation) and the frequency of Ind- mutations (W-mutagenesis). During transfection of B. subtilis cells by UV-irradiated prophage DNA isolated from lysogenic cells B. subtilis (phi 105 c+) c-mutants of the phage are obtained in high yield only in conditions of W-mutagenesis, i.e. in UV-irradiated recipient cells. These data show that there is no substantial spontaneous induction of error-prone SOS-repair system in the competent cells of B. subtilis.

Bacillus subtilis↗
PubMed1980

[Escherichia coli K-12 mutants with increased resistance to ionizing radiation. I. Isolation and study of cross resistance to different agents].

The strains of Bacillus subtilis actively exchange genetic material during joint incubation on a properly composed selective solid medium at 37 degrees C. Predominantly, colonies of multiple recombinants are formed. If DNase is present in the medium, total number of recombinant colonies and the share of colonies of multiple recombinants decrease. At 46 degrees C the recombination process is inhibited. The results obtained are discussed using two hypotheses: 1) a donor cell transfers a significant part or even whole chromosome to a neighbouring recipient cell, 2) recombinations occur successively in mini-clones of intermediate recombinants. It is suggested that the phenomenon observed is close to the natural genetic transformation in Bac. subtilis.

Escherichia coli↗
PubMed1978

W-reactivation and W-mutagenesis of gamma-irradiated phage lambda.

UV irradiation of Escherichia coli wild-type cells manifested the phenomena of W-reactivation (WR) and W-mutagenesis (WM) of phage lambda irradiated by 60Co gamma-rays in broth. WR of gamma-irradiated phage was half as efficient as that of UV-irradiated phage, although the frequency of c mutations in conditions of WR was about the same in both phages. The xthA and recBrecC sbcB mutants were practically identical with wild-type cells in respect of WR and WM of UV- and gamma-irradiated phage. As in UV-irradiated phage, WR and WM of gamma-irradiated phage were absolutely dependent on the recA+ and lexA+ genes of the host cell. WR and WM required much smaller doses of UV radiation for induction in polA1 and uvrB mutants. The lig-ts mutant, temperature sensitive in polynucleotide ligase, was deficient in WR and WM of UV- and gamma-irradiated phage at the semi-permissive temperature of 37 degrees. The uvrE502 mutant and the allelic recL152 strain were absolutely deficient in WR and WM of gamma-irradiated phage. In UV-irradiated phage WR was reduced, but not eliminated, in the uvrE mutant, and WM was entirely suppressed. This is another example of uncoupling of WR and WM which shows that several repair systems are active in WR but only some of them are mutagenic.

Coliphages↗
PubMed1977

[W-reactivation and W-mutagenesis in UV-irradiated phage phil05 of Bacillus subtilis].

The survival of UV-irradiated phage ø105 on the lawns of several strains of Bacillus subtilis: wild type (strain 168) and 11 recombination-defficient mutants (recA1, recB2, recB3, recB19, recD27, recF15, recF18, recK4, recM13, recL16 and recO61) was investigated. All rec mutants have the phenotype Hcr+, i.e. normally host-cell reactivate UV-damaged phage. Small doses of UV-irradiation given to the wild type (rec+) cells increase the probability of survival of UV-irradiated ø105 phage (W-reactivation) and significantly enhance the frequency of c-mutants (W-mutagenesis). Maximal frequency of clear mutations in conditions of W-mutagenesis is 3-10(-3), i.e. is 100 times higher than the spontaneous background. Various rec mutations of host cells only diminish the level of W-reactivation but do not eliminate it completely. The most deficient in W-reactivation is recD27 mutant. Mutations recB2, B3, B19 and O61 have no effect on W-mutagenesis of UV-irradiated phage ø105 and on UV-induction of ø105, F15,F18 and L16 mutants. UV-irradiation of lysogenic cells of these mutants does not induce ø105 prophage.

Bacillus subtilis↗
PubMed1975

Study of genetic effects of high energy radiations with different ionizing capacities on extracellular phages.

The inactivating and mutagenic action of high-energy radiations with different ionizing capacities (gamma-rays, protons, alpha-particles and accelerated ions of 12C and 20Ne) was studied by using coliphages lambda11 and SD as subjects. In particular the role of irradiation conditions (broth suspension, pure buffer, dry samples) and of the host functions recA, exrA and polA was investigated. The dose-response curve of induced mutagenesis was studied by measuring the yield of vir mutants in lambda11 and plaque mutants in SD. The following results were obtained. (1) The inactivation kinetics of phages under the action of gamma-rays and protons was first order to a survival of 10(-7). Heavy ions also showed exponential inactivation kinetics to a survival of 10(-4). At higher doses of 20Ne ion bombardment some deviation from one-hit kinetics was observed. For dry samples of phages the dimensions of targets for all types of radiation were approximately proportional to the molecular weights of phage DNA's. For densely ionizing radiation (heavy ions) the inactivating action was 3-5 times weaker than for gamma-rays and protons. (2) Mutagenesis was observed for all types of radiation, but heavy ions were 1-5-2 times less efficient than gamma-rays. For both phages studied the dose-response curve of mutagenesis was non-linear. The dependence on the dose was near to parabolic for lambda11. For SD a plateau or maximum of mutagenesis was observed for the relative number of mutants at a survival of about 10(-4). (3) Host-cell functions recA and exrA were practically indifferent for survival of gamma-irradiated phage lambda11, but indispensable for mutagenesis. Mutation recAI3 abolished induced vir mutations totally and exrA- reduced them significantly. The absence of the function polA had a considerable influence on phage survival, but no effect on vir mutation yield (if compared at the same survival level). (4) In conditions of indirect action of gamma-rays no vir mutations were induced. This is regarded as evidence that the single-strand breaks formed under indirect action conditions cannot serve as pre-mutational damage in DNA.

Alpha Particles↗