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M N Kolot

Publications and source records attributed to M N Kolot.

16 recordsLinked to original sources
PubMed1991

[Analysis of the nucleotide sequence of a small colicinogenic plasmid Cold gene coding for lysis].

The nucleotide sequence of a DNA fragment of a small colicigonenic plasmid Cold-CA23 containing the lysis gene cdl has been defined. An open reading frame has been found within the fragment for 48 amino acid polypeptide with the molecular mass 4920 Da. The polypeptide is homologous to the lysis proteins encoded by the small colicinogenic plasmids ColE1 and CloDF13. The homology was also found for the structural and functional arrangement of the cdl gene and the plasmid CloDF13 lysis gene. The analysis of the possible secondary structures of the lysis protein encoded by cdl gene has revealed the amino acid sequences able to form the alternative structures. The described feature is supposed to be required for lysis protein translocation from cytoplasmatic to outer membrane of Escherichia coli cells.

Amino Acid Sequence↗
PubMed1990

Par site of the ColN plasmid: structural and functional organization.

A par site involved in the resolution of multimeric plasmid DNA forms was localized in a 679 bp SalI-KpnI fragment of the small colicinogenic plasmid ColN. It was shown that replication of the monomeric pUC19 recombinant plasmid carrying the par region of ColN does not result in the formation of significant numbers of multimers. In order to function properly, the ColN multimer resolution mechanism requires the product of the xerA gene, just as in the case of ColE1. Nucleotide sequence analysis of the par region of ColN revealed substantial homology with the par locus of the ColE1 plasmid. The results of this study and data from the literature indicate that the par sites of ColE1-type plasmids have substantial homology and the same mechanism of action, and in fact represent a universal stability module for small multicopy colicinogenic plasmids.

Bacteriocin Plasmids↗
PubMed1989

Stability of the pBR322 plasmid as affected by the promoter region of the tetracycline-resistance gene.

A region affecting the pBR322 plasmid maintenance has been located within the region of the TcR gene promoter. On the basis of stability analysis of pBR322 derivatives comprising the modified region of the TcR gene, we deduced that it is the nucleotide sequence localized in the region of the HindIII site that causes destabilization of the plasmid and not the TcR gene product or active transcription of this region. The destabilizing effect is manifested both in cis and in trans.

Chromosome Deletion↗
PubMed1989

[Structural-functional analysis of the par-region of ColE1 plasmid].

The DNA fragment identical to the right shoulder of the inverted repeat from the par-region of ColE1 plasmid has been synthesized chemically. It is shown to participate in the plasmid multimers resolution and to define the stable inheritance of the plasmid pKS1 containing the fragment in Escherichia coli C600 cells as well as in the multirecombinogenic strain Escherichia coli JC8679. The efficiency of the fragments functioning in Escherichia coli JC8679 is not enough for resolution of all forms of oligomeric pKS1 DNA. The site for recombinase action is found to be located in the synthesized oligonucleotide. However, some extra sequences of DNA located within the region of inverted repeat are necessary for maximally efficient functioning of the recombinase, the enzyme participating in plasmid multimers resolution.

Chromosome Inversion↗
PubMed1988

[Molecular cloning of plasmid ColIb-P9 genes responsible for its mutator function].

The localization of plasmid ColIb-P9 muc genes mediating the plasmids protective and mutagenesis-increasing activity has been determined. The increase of muc genes dose by cloning them within the multicopy vector has been shown to repress the mutator function of the plasmid. No essential homology has been revealed between ColIb-P9 muc gene nucleotide sequences, pKM101 muc genes with a similar function, and umuDC chromosome genes. It has been shown that the synthesis of 38 KD protein is essential for the manifestation of the mutator function of the plasmid.

Bacteriocin Plasmids↗
PubMed1987

[The nature of typhimuricin--a substance produced by Salmonella typhimurium LT2 and relation of its synthesis to the cryptic plasmid].

The effect of typhimuricin on Escherichia coli K12 cells and the properties of this substance produced by Salmonella typhimurium LT2 have been studied. The obtained data permit one to conclude that typhimuricin is similar to the aminoacid L-valine or the chemical very similar to it in properties. The synthesis of typhimuricin is not controlled by the cryptic plasmid present in Salmonella typhimurium LT2 cells. The experiments aimed at isolation of enterobacterial strains producing low molecular mass antibiotics--microcines have been done. It was found that the capability to produce macrocines is not widespread among the isolates of enterobacteria.

Bacteriocins↗
PubMed1986

[Organization and gene expression of plasmid ColD-CA23 connected with colicin biosynthesis].

Organization of genes for colicin, immunity and lysis and regulation of their expression in colicinogenic plasmid ColD-CA23 were studied. The polypeptides synthesised in minicells carrying the ColD plasmid, its Tn5 mutants and the recombinant plasmids constructed by cloning the ColD EcoRV fragments on pBR325 were analysed. The position of the colicin gene promotor is established and direction of the gene transcription determined. The immunity gene was shown to be expressed independently of the gene coding for colicin and believed to have its own SOS-independent promotor. Treatment with mitomycin C of the ColD-carrying cells leads to induction of the synthesis both of colicin and of a 10 KD protein responsible for cell killing and lysis. This protein can be detected in a cultural medium under lysis. Plasmid mutations abolishing synthesis of the lysis protein prevent release of colicin. The colicin and lysis genes are arranged in an operon, the lysis gene being situated next to that of colicin. The ColD genetic map is suggested.

Chromosome Mapping↗
PubMed1985

[Organization of the genes responsible for colicin Ib synthesis and immunity to it in plasmid ColIb-P9].

To study the localization and expression of the ColIb-P9 plasmid genes responsible for colicin Ib synthesis and immunity to it, we isolated a series of Tn5 insertion mutants of recombinant plasmid pIV41 containing the colicin Ib gene in EcoRI fragment of ColIb-P9 (2.7 kb) and the deletion plasmid carrying only a part of the colicin gene. The direction of colicin Ib gene transcription was determined by the analysis of the polypeptides synthesized in minicells carrying the mutant plasmids. The pIV41 plasmid containing cells have been shown to be resistant to both colicin Ib and Ia activities. This type of resistance is usually associated with chromosomal mutations resulting in loss of cell receptors for colicin Ib adsorption. Apparently, the EcoRI fragment of ColIb-P9 studied contains no gene responsible for immunity to colicin. It has been shown that this gene is a portion of SalI fragment (22 kb) of the ColIb-P9, the fragment also carrying the gene which mediates synthesis of colicin Ib.

Chromosome Deletion↗
PubMed1979

[Exogenous orthophosphate regulation of ATPase activity of E. coli cells].

The effect of exogenous orthophosphate and mutations in genes, regulating the Pi transport system, on the ATPase activity of E. coli subcellular fractions was studied. It was shown that the orthophosphate starvation resulted in the cessation of the increase in the ATPase activity of membranes and was accompanied by the increase in the analogous activity of a soluble fraction at the expense of the derepression of alkaline phosphatase possessing this activity. The disturbance, resulted from the mutation of protein components participating in the specific binding and transport of orthophosphate, changed the ATPase activity of subcellular fractions: increased the ATPase activity of soluble fraction (independently of the presence of orthophosphate in medium), did not affect significantly the activity of membrane--bound ATPase in the presence of orthophosphate and decreased this activity in the absence of orthophosphate. The data obtained point to the fact that components, binding exogenous orthophosphate and transporting it into a cell, affect the rigidity of the ATPase bound E. coli cytoplasmic membrane. Mutations resulting in the defect in these components relax this bound and lead to the detection of ATPase proper in the periplasm.

Adenosine Triphosphatases↗
PubMed1979

[Interrelationship between metabolic and genetic regulation of alkaline phosphatase and poly- and pyrophosphatases].

The effects of orthophosphate and mutations in the regulatory genes of alkaline phosphatase on the activities of pyrophosphatase and polyphosphatase of E. coli were studied. It was shown that orthophosphate represses the synthesis of alkaline phosphatase as well as that of polyphosphatase without having any effect on pyrophosphatase. The genes phoR and phoS are involved in the formation of a repressory complex both for alkaline phosphatase and polyphosphatase. The gene phoT is probably involved in a partial repression of pyrophosphatase synthesis.

Acid Anhydride Hydrolases↗
PubMed1978

[Interrelationship between metabolic and genetic regulation of alkaline and acid phosphatases in E. coli cells].

The effect of exogenous orthophosphate and mutations in regulatory genes of alkaline phosphatase on the level of nonspecific acid phosphatase was studied. The level of this enzyme as well as the level of alkaline phosphatase were shown to be regulated by exogenous orthophosphate being derepressed under phosphate starvation. The derepression of acid phosphatase is accompanied by more rapid secretion of enzyme from membranes to soluble fraction. Mutations in all the four regulatory genes decrease the level of enzyme in cells. Genes phoR and phoS, participating in regulation of alkaline phosphatase, are required for the derepression of acid phosphatase under the conditions of phosphate starvation.

Acid Phosphatase↗
PubMedDate not supplied

[Structural-functional organization of the par region of the ColN plasmid].

In the 679 b.p. SalI-KpnI-fragment of the small colicinogenic plasmid Co1N, the par-region has been localized, functioning at the expense of resolution of plasmid DNA multimer forms. It has been shown that the replication process of the monomeric form of the recombinant plasmid containing the Co1N par-region do not result in formation of a considerable number of multimers. Gene xer A product is necessary for the functioning of the multimer resolution mechanism of Co1N as well as Co1E1. Nucleotide sequence analysis of the Co1N par-region revealed the presence of essential homology with the par-locus of plasmid Co1E1. Results obtained in this work and data from literature indicate that par-regions of the Co1E1-type plasmids possess considerable homology, function according to a similar mechanism and represent the universal stability module of multicopy colicinogenic plasmids.

Bacteriocin Plasmids↗
PubMedDate not supplied

[Structuro-functional organization of segments of Co1A plasmid DNA, determining its stable inheritance].

Two par regions were localized within the structure of a small colicinogenic plasmid ColA. One of them functions at the expense of plasmid multimere resolution. Analysis of the nucleotide sequence of the region revealed the existence of essential homology with the par locus of plasmid ColE1. As compared to E. coli C600, the function of multimere forms' resolution of plasmid DNA in E. coli C is reduced or absent due to par regions of the ColE1 type. Par regions of various degrees of homology with the par locus of ColE1 were localized by Southern hybridization within the structure of colicinogenic plasmids ColN and ColD. The stabilization of the colicinogenic plasmids is believed to be also determined by the functioning of genes connected with the synthesis and action of colicin.

Bacteriocin Plasmids↗
PubMedDate not supplied

[Effect of a fragment of pBR322 plasmid in the region of tetracycline resistance gene on the stability of this plasmid].

A fragment destabilizing the pBR322 plasmid has been localized in the region of pBR322 tet gene promoter. On the basis of stability analysis of pBR322 derivatives comprising the modified region of tet gene, we deduced that it is the DNA sequence localized at the beginning of tet gene in the region of HindIII splitting site that ensures the plasmid destabilization, and not tet gene product or the active transcription of this region. The destabilizing effect of this fragment of the plasmid is manifested both in cis and in trans. Possible molecular mechanisms of the phenomenon are discussed.

DNA, Bacterial↗
PubMedDate not supplied

[Structural and functional organization of the colicin operon in the ColD-CA23 plasmid].

The organization of the genes involved in colicin D synthesis was studied. These are colicin, immunity and lysis genes. The nucleotide sequence of the immunity gene, its structural and regulatory regions were determined. This gene was shown to be located next to the colicin gene on the same strand and followed by the lysis gene. When colicin synthesis is induced with mitomycin C the immunity gene is transcribed from the general SOS-dependent promotor as a part of the colicin operon. However it has its own SOS-independent promotor in normal growth conditions. A high homology in amino acid sequences of Co1D lysis protein and that of Co1E1, Co1E2, Co1E3, Co1DF13, Co1A was revealed. A detailed scheme of Co1D-CA23 colicin operon structural organization is suggested.

Amino Acid Sequence↗