[Properties of natural interspecific hybrids of transposable phages of Pseudomonas aeruginosa: specific characteristics of phage PL24 transposition].
Properties of natural hybrid transposable phages (TP) of Pseudomonas aeruginosa, including phage PL24 and lysogens for this phage, were studied. PL24 possesses the properties of TP from two previously described groups, B3 and D3112. Its genome, unlike the genome of D3112, contains many sites susceptible to the SalGI restriction endonuclease and possesses no more than 100 nucleotides of bacterial origin located at the left genome end. However, unlike B3, phage PL24 failed to induce auxotrophic mutants upon integration in the bacterial genome. This phage differed from both B3 and D3112 in sensitivity to chloroform treatment. A more detailed examination of a group containing 25 randomly isolated lysogens for phage PL24 revealed previously unknown processes occurring at early stages of bacterial lysogenization. There are at least two different modes of cell lysogenization with phage PL24. In the first case, the emerging lysogens contained a single prophage genome located (in each lysogen) at individual sites. In the second case, polylysogenic bacteria appeared, and, after primary integration of a phage genome, replicative transposition occurred at new sites (often accompanied by the appearance of prophage clusters at these sites). The choice of the mode of lysogenization can be determined both by differences in the physiological state of bacteria and by specific features of phage PL24, which possibly affect the time of repressor accumulation to the concentration sufficient for blocking phage growth or the stability of the lysogenic state.
Mit'kina
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LN
State Research Institute of Genetics and Selection of Industrial Microorganisms, Moscow, Russia.
Krylov
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VN
D004251:DNA Transposable Elements; D004279:DNA, Viral / Q000235:genetics; D004587:Electrophoresis, Agar Gel; D008242:Lysogeny; D009693:Nucleic Acid Hybridization; D017105:Pseudomonas Phages / Q000235:genetics*; D011550:Pseudomonas aeruginosa / Q000821:virology*
D004251:DNA Transposable Elements; D004279:DNA, Viral