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At least 757 records · Page 42Linked to original sources
PubMed2003

[Changes in Staphylococcus aureus susceptibility to bactericidal action of teicoplanin in the presence of different prophages in the bacterial genome].

The influence exerting by lysogeny state on the susceptibility of Staphylococcus aureus to bactericidal action of teicoplanin was studied. In this aim the standard, non-lysogenic, bacteriophage-free S. aureus NCTC 8325-4 strain was lysogenized with 10 different, bacteriophages obtained in our laboratory. All bacteriophages were derived from multiresistant S. aureus strains and all were able to convert staphylokinase. For all derivatives MBCs and MICs of teicoplanin were determined. In the case of four strains the ratio MBC/MIC showed the presence of tolerance to teicoplanin (MBC/MIC > or = 32) and was significantly higher than in the case of the parent strain NCTC8325-4. In the case of two strains this ratio was smaller than for parent strain. Only small correlation with our previous results obtained for vancomycin was observed.

Animals↗
PubMedDate not supplied

[Structural organization and control of expression of the sop-operon of linear plasmid prophage N15].

Stable inheritance of bacterial chromosomes and low-copy-number plasmids depends on the active partition of replicated molecules between daughter cells. The partition mechanism is well known for circular plasmids F and P1. The mechanism of partition of linear replicons was studied with the example of bacteriophage N15, which persists as a linear plasmid with covalently closed ends on lysogeny, rather than integrating into the Escherichia coli chromosome. Since stable inheritance of N15 is due to the sop operon homologous to sop of the F plasmid, the control of expression of the N15 sop genes was analyzed. The sop promoter (Psop) contains a binding site for bacterial IHF and five CTTTGC copies, which overlap the -35 and -10 elements. The Sop proteins were shown to interact with a Psop-containing DNA fragment in vitro. Transcription of the sop operon is regulated by the Sop proteins: SopA represses Psop, and SopB enhances the repression, having no effect on the promoter activity in the absence of SopA. In N15 lysogenic cells, Psop proved to be repressed. This regulatory mechanism was assumed to ensure production of SopA and SopB in amounts required for the segregation stability of N15 and to neutralize occasional fluctuations of their concentration in the cell.

Bacteriophages↗
PubMed1991

[Effect of prophages on transfer frequency of conjugative plasmid G 873].

Transfer of the conjugative plasmid G873 on filters and mixed cultivation of the donor and recipient cells in liquid media is described. In the both systems the use of the lysogenic recipient cells (phages of serogroups B and F) in the crossings increased mor than 100-fold the frequency of plasmid transfer. The conjugative transfer of the plasmid in the mixed cultivation system was proved. The conjugative transfer required the presence (while not obligatory) of calcium chloride and was restricted by the serum factors.

Animals↗
PubMedDate not supplied

Prophage induction by alkylating ethyl methylaminosulfonate.

Treatment of the lysogenic strain M. lysodeikticus 53-40 (N5) with ethyl methylaminosulfonate results in a slight increase in infective center concentration of N5 phages which is only detectable once disturbing cells had been eliminated by lysozyme. After conversion of ethyl methylaminosulfonate with radioactive labelled guanosine at 37 degrees C, N7-ethyl-guanine could be ascertained. Therefore the biological activity of the drug may be due to an ethylation of DNA.

Alkylation↗
PubMed1986

Use of phage lambda CI857AprTcrN derivative for isolation of prophage-free cells.

A method for obtaining nonlysogenic bacteria from wild-type phage lysogenized strains using phage lambda with AprTcr markers and double amber-mutation in N gene is proposed. When the lysogenic culture is infected with antibiotic-resistant phage, the nonlysogenic cells present in the population are lysogenized and isolated on selective medium with Ap and Tc. Subsequent culturing of lysogenized cells on media without antibiotics leads to phage elimination due to its instability.

Bacteriophage lambda↗
PubMed1985

[Transfer of prophage Mu into methylotrophic bacteria in the plasmid RP4].

Bacteriophage Mu genome has been transferred into the cells of Pseudomonas methanolica and Methylobacterium sp. SKF240, that are naturally resistant to the bacteriophage, as a fragment of a hybrid plasmid RP4::Mu cts62. Temperature induction of the bacteriophage results in host cell lysis. Plasmid RP::Mu cis62 is maintained in methylotrophic cells presenting a cointegrative structure. The genetic and electrophoretic, analyses of the DNA isolated from transconjugant cells have confirmed the conclusion. Bacteriophage Mu propagation has been shown to be restricted in methylotrophic cells.

Bacteriophage mu↗