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V N Krylov

Publications and source records attributed to V N Krylov.

At least 91 records · Page 5Linked to original sources
PubMed1983

[Changes in the nature of the cell growth of Pseudomonas aeruginosa PAO from the conjugative introduction of plasmid RP4].

Conjugative transfer of RP4 plasmid into Pseudomonas aeruginosa PAO at 30 degrees C results in inhibition of growth of plasmid-containing cells. No inhibition of growth of exconjugants takes place under special conditions (usage of minimal M9 medium or incubation at 42 degrees C) and when cells have specific mutations. These mutations were designated as rpm (RP4 maintenance). Some of them render cells resistance to temperate phages of P. aeruginosa. The frequency of transfer of RP4 into PAO1rpm, in comparison with that of transfer into PAO1rpm+, is increased 7-10 times and is equal 0.8-0.9 per a donor cell.

Anti-Bacterial Agents↗
PubMed1983

[Multiplicity of the integration sites of Mu-like bacteriophages into Pseudomonas aeruginosa chromosome and plasmids].

It has been shown that D3112 prophage can be integrated into different chromosomal sites of Pseudomonas aeruginosa. The other Mu-like phages (B3, B39, PM69) are capable to insert their genomes during infection process into the plasmids RPL11, RMS148, RMS163. Their integration is occasionally accompanied by formation of mutations in plasmid genes. The certain types of auxotrophic and morphological mutants (thi, met, pigmented, met - pigmented) can be found at a frequency about 10% among survivors after a long (48 h) incubation at 42 degrees C of PAO (D3112cts15) or PAO (B39cts1) lysogens. The spectrum of mutants might depend on the time of heat induction. After a short exposure (10-20 min), arg and pigmented mutants can be found. Accumulation of certain kinds of mutants after heat induction is quite a specific phenomenon for Mu-like phages; heat induction of PAO (F116ts245) does not lead to selection of these specific bacterial mutants (F116 is unrelated to Mu-like phages and has extrachromosomal location).

Attachment Sites, Microbiological↗
PubMed1983

[Use of deletion mutants of plasmid RP4::D3112 for the genetic analysis of Pseudomonas aeruginosa bacteriophage D3112].

The hybrid plasmid RP4::D3112 becomes unstable in Escherichia coli K-12 cells under certain growth conditions. The deletion mutants of this plasmid are formed at a high frequency. All the deletions selected have a specific feature: they start in the left end, at the point of joining of plasmid and phage DNA, and remove different portions of the phage genome. The deletion mutants have been used for genetic mapping of D3112. We have localized the repressor gene cI (0-1.3 kb), 3 early genes (1.3-14.2 kb) and two groups of late genes (14.2-29.9 and 29.9-38 kb). Electron microscope studies of RP4::D3112 DNA and its deletion derivatives have shown that integration of D3112 genome in RP4 occurs through the ends of the genome, without permutations. It appears that bacterial nucleotide sequences joined to DNA from mature D3112 particles, to the right end of D3112 genome, are lost. Thus, transposable phages D3112 of Pseudomonas aeruginosa and E. coli Mu phage have some similarities in the genome organization and in the way of their integration into the host DNA.

Bacteriophages↗
PubMed1983

[Regulation of int gene expression in phage phi 81].

Phi 81 phage, like lambda, was shown to possess, in addition to cI (repressor) gene, two other genes--cII and cIII, essential for immunity establishment. Expression of phi 81 int gene is positively controlled by cII and cIII gene products. The products of cII and cIII genes of phi 81 phage do not complement analogous lambda genes functions.

Coliphages↗
PubMed1982

[Integration of the genome of the Mu-like Pseudomonas aeruginosa bacteriophage D3112 into plasmid RP4 and its hybrid plasmid transfer into Pseudomonas putida and Escherichia coli C600 bacteria].

The genome of a Mu-like bacteriophage D3112 specific for Pseudomonas aeruginosa was integrated in vivo into the RP4 plasmid. The fact of integration has been proved by two experiments: 1. The loss of RP4 plasmid is accompanied by loss of D3112 prophage; 2. Transfer of the plasmid by conjugation from Pseudomonas aeruginosa into bacteria of other species - P. putida PgG1 or Escherichia coli C600 leads to the occurrence of clones of these species which liberate phage capable of growing on the lawn of P. aeruginosa bacteria. The integrated state of D3112 inserted into RP4 is stable in P. aeruginosa, E. coli, P. putida. The transfer frequency of RP4 with integrated D3112 prophage into different bacteria which do not contain homoimmune prophage is essentially lower than that of the RP4 having no D3112 prophage. Specific manifestation of D3112 genome activity in E. coli cells is the sensitivity of cell growth to lower temperature (30 degrees C) of incubation.

Bacteriophages↗
PubMed1982

[Interaction of Pseudomonas aeruginosa plasmids and mu-like phages: the suppression of the early stages of cell infection by phage D3112 in the presence of plasmid RPL11].

The growth of Mu-like, D3112, B39 and B3 bacteriophages of Pseudomonas aeruginosa on bacterial strains containing R plasmids was studied. Plasmids RPL11, Rms148 and Rms163 were shown to interfere with phage growth: 1) D3112 and B39 phages do not produce plaques on a lawn of PAO1 (Rms148) giving e.o.p. less than 10(-9); 2) RPL11 plasmid restricts phage D3112 growth (e.o.p. less than 10(-9), the growth of phage B3 being also restricted by this plasmid, though in considerably less extent; 3) phage B39 makes small and very turbid plaques on a lawn of PAO1 (Rms163) with e.o.p. 0,13, while c mutants form clear plaques on this lawn and grow with e.o.p. 1,0. The interference of plasmid RPL11 with phage D3112 growth was examined in detail. The plasmid did not affect phage D3112 adsorption and no restriction of phage DNA in R+ cells was found. However, phage genes controlling establishment of lysogeny and the lytic cycle were not expressed after infection. It was observed though, that if a cell contains both prophage D3112 and plasmid RPL11, no interference with repressor synthesis or phage development takes place after induction of prophage. The results obtained allow to conclude that: 1) RPL11 plasmid interference with phage D3112 growth is caused by the plasmid effect on one of the early stages in the development preceding phage DNA integration; 2) the process of primary integration after infection and that of reintegration of DNA after prophage induction are likely to differ.

Adsorption↗
PubMed1982

[Expression of the genome of Mu-like phage D3112 specific for Pseudomonas aeruginosa in Escherichia coli and Pseudomonas putida cells].

The behavior of Escherichia coli cells carrying RP4 plasmid which contains the genome of a Mu-like D3112 phage specific for Pseudomonas aeruginosa was studied. Two different types of D3112 genome expression were revealed in E. coli. The first is BP4-dependent expression. In this case, expression of certain D3112 genes designated as "kil" only takes place when RP4 is present. As a result, cell division stops at 30 degrees C and cells form filaments. Cell division is not blocked at 42 degrees C. The second type of D3112 genome expression is RP4-independent. A small number of phage is produced independently of RP4 plasmid but this does not take place at 42 degrees C. No detectable quantity of the functionally active repressor of the phage was determined in E. coli (D3112). It is possible that the only cause for cell stability of E. coli (D3112) or E. coli (RP4::D3112) at 42 degrees C in the absence of the repressor is the fact of an extremely poor expression of D3112. In another heterologous system, P. putida both ways of phage development (lytic and lysogenic) are observed. This special state of D3112 genome in E. coli cells is proposed to be named "conditionally expressible prophage" or, in short, "conex-phage", to distinguish it from a classical lysogenic state when stability is determined by repressor activity. Specific blockade of cell division, due to D3112 expression, was also found in P. putida cells. It is evident that the kil function of D3112 is not specific to recognize the difference between division machinery of bacteria belonging to distinct species or genera. Protein synthesis is needed to stop cell division and during a short time period this process could be reversible. Isolation of E. coli (D3112) which lost RP4 plasmid may be regarded as an evidence for D3112 transposition in E. coli. Some possibilities for using the system to look for E. coli mutants with modified expression of foreign genes are considered.

Bacteriophages↗
PubMed1982

[Genetic and phenogenetic study of the ts-mutant group of Pseudomonas aeruginosa PA01 phage phi KZ].

A group of ts mutants of phi KZ phage specific for Pseudomonas aeruginosa was isolated and studied. A phi KZ phage particle has a unique feature: a specific structure as an internal body concerned with DNA packaging which is present in the phage capsid. Ts mutants were distributed into complementation groups. The time of the development block when grown at elevated temperatures was determined for mutants from several groups, the exact stage of the block having been defined for some late ts mutants. As was found for ts759, the stage of connection of heads containing DNA and the inner body with tails was blocked. The results obtained with ts759 allowed to prove the circular location of fibrous material (DNA?) around the inner body. The conditions for phage crosses were revealed. The genetic map of phi KZ is circular. It may be concluded, considering the linear phi KZ DNA structure in capsids, that circular permutations of phage DNA take place during phage maturation or DNA packaging.

Bacteriophages↗
PubMed1982

[Detection of transduction by virulent bacteriophage phi KZ of Pseudomonas aeruginosa chromosomal markers in the presence of plasmid RMS148].

A virulent phage of Pseudomonas aeruginosa, phi KZ which is able to package DNA of 210 MD is a general transducer. The transducing activity of phi KZ can be revealed when using recipient bacteria containing RMS148 plasmid (the P7 group of incompatibility). This plasmid blocks the development of phi KZ and prevents the phage to kill bacteria. General transduction mediated by phi KZ may be useful for the primary localization of genetic markers in P. aeruginosa.

Bacteriophages↗
PubMed1981

[Isolation and analysis of phage-resistant Pseudomonas putida mutants using new bacteriophages].

Three new bacteriophages of Pseudomonas putida PpG1 have been isolated. Bacteriophages differ in many characteristics and are unrelated. Phage-resistant mutants of Pseudomonas putida PpG1 are selected using these phages and pf16 bacteriophage. No lysogenic variants were detected among these mutants. They have been distributed in seven groups according to their resistance to bacteriophages. The resistance to PMW phage was caused by at least two different mutations. Some of the phage-resistant mutants seem to cause the killing effect on Pseudomonas putida PpG1 cells.

Bacteriophages↗
PubMed1981

[Pseudomonas putida PpG1 resistance to different bacteriophages].

Cris-cross resistance analysis has been accomplished for some Pseudomonas putida PpG1 mutants resistant to pf16, af, tf and PMW phages. On the basis of the results, a formal scheme of the receptor sites for these phages on the bacterial cell surface was drawn. Study of the sensitivity of P. putida PpG1 phage-resistant mutants an unexpected phenomenon. Some of the phages specific to P. putida B-21 and B-31 which did not adsorb on the PpG1 strain acquired the ability on certain types of the PpG1 phage resistant mutants. Mutants of P. putida B-21 and B-21 resistant to specific phages did not maintain the growth of pf16, af, tf or PMW phages.

Adsorption↗
PubMed1980

[Pseudomonas aeruginosa bacteriophages with DNA structure similar to the DNA structure of Mu1 phage. II. Evidence for similarity between D3112, B3, and B39 bacteriophages: analysis of DNA splits by restriction endonucleases, isolation of D3112 and B3 recombinant phages].

It is found that bacteriophages B3 and B39 specific for Pseudomonas aeruginosa have the same genome structure as previously described phage D3112. On the right (S) end of their genomes a variable non-phage DNA is located (approximately 0.9-2.5 kilobases for different phages). It is probable that this variable DNa has its origin from different regions of bacterial chromosome. In genome of one of the phages, B3 phage, such variable DNA (not more than 150 base pairs) was found on the left end of DNA molecule. Isolation of a viable B3XD3112 recombinant phage and analysis of its genome with restriction technique and with studies of homo- and heteroduplex molecules had confirmed genetical relationship of B3 and D3112. Some essential non-homology of B3 and D3112 DNAs have been found on the right ends of genomes of the phages.

Bacteriophages↗
PubMed1980

[Transducing phages of Pseudomonas aeruginosa related to phage F116L].

New phages K104 and B26, which are relative to F116L by a number of biological characters, appeared to show general transducing activity. Phage K104 transduces all tested markers with higher frequency than the phage B26. Linkage of the bacterial markers pair ilv202--met28 durspectively. When recipient bacteria lysogenic for phages K104 and B26 are used, frequencies of transduction by phage F116L are decreased. In the presence of F116L prophage the frequency of transduction by phage B26 is 10-fold increased. Phages B26 and F116L do not grow on bacteria lysogenic for these phages. Phage F116L does not grow on the lawn of bacteria, lysogenic for phage K104, while phage B26 grows on the same lawn with the efficiency of plating about 10(-2).

Bacteriophages↗
PubMed1978

[Construction and study of a new type of phage lambda DNA vector molecule].

A group of lambda mutants (mutants lambda 0) harbouring lesser number of EcoRI restriction sites on DNA molecules was selected. lambda3-1 recombinant (genotype lambdab221amgamma210Sr1lambda3+c-Px) was created by crosses of lambda02 phage with other lambda mutants. This phage DNA may be used as a vector molecule which makes it possible to select easily phages harbouring insertions of EcoRI DNA fragments. The maximal size of DNA fragment, the insertion of which would not decrease lambda3-1 viability, is 7.7 megadaltone. Lambda3-1 DNA has three regions heterological to lambda DNA, two of which probably include sites SRIlambda4 and SRIlambda5 and some juxtaposed genes. For example, Ptgene of lambda phage in juxtaposition with site SRIlambda4 is substituted by Px gene on the lambda3-1 DNA molecule.

Coliphages↗
PubMed1978

[Genetic study of bacteriophage phi81. II. Gene localization in the right arm of the phage chromosome and a comparison of phage phi81 with phages lambda and phi80 in regard to gene functions].

Data on genetic investigation on lambdoid bacteriophage phi81 made possible to localize the cos site on the prophage genetic map. Four essential genes and the gene c1 are located in the right arm of the phage genetic map. Regulatory genes of phage phi81 are found to be uncapable of functional substitution of lambda phages regulatory genes N and Q. It is discovered that some late genes of phage phi80 can be substituted with respective phage phi81 genes. No substitution possibility was observed for a number of early genes of phage phi80.

Chromosome Mapping↗
PubMed1978

[Pseudomonas bacteriophage phiKZ--possible model for studying the genetic control of morphogenesis].

A description of structure and some bilogical properties of a new virulent Pseudomonas phage, phiKZ, is given in the paper. Phage phiKZ has unique characteristics of particle (a large size of the head and the presence in the head of a structure which is visible on electron micrographs as crosswise striated substance). A cause of high-titer phage phiKZ formation on plates has been investigated. Characteristics of single step growth experiments, sensitivity of free phage particles to heating, SDS-treatment, UV-light, cycles of freezing-thawing, osmotic shocking are determined. No exclusion is found of homologous phage at early stages of infection bacteria with phiKZ. Mutants of phiKZ with changed plaque morphology are isolated; the possibility of a recombination between the mutants is demonstrated. It is supposed that phage phiKZ may be used as excellent model for the study of genetic control of morphogenesis and packing of DNA in the phage head.

Bacteriophages↗