[Expression of pel genes of Erwinia chrysanthemi ENA49 in Erwinia carotovora var. atroseptica 36A cells]. / Ekspressiia pel-genov Erwinia chrysanthemi ENA49 v kletkakh Erwinia carotovora var. atroseptica 36A.

Erwinia atroseptica 36A cells were transformed by the recombinant plasmid pPL5-1 (a derivative of the vector plasmid pUC19) containing pelb and pelc genes which encode pectate lyases of Erwinia chrysanthemi ENA49. Synthesis of pectate lyases PLB and PLC determined by the cloned pel genes is constitutive in Erwinia atroseptica 36ApPL5-1 cells and not inducible by sodium polypectate. The major part of these enzymes was accumulated in the periplasmic fraction of Erwinia atroseptica and cells were unable to efficiently secrete the enzymes into the cultural medium. Synthesis and secretion of the native pectate lyases by Erwinia atroseptica harboring the plasmid were as efficient as by the parental cells. The obtained results suggest the high specificity of pectate lyase secretory systems of kindred Erwinias.

[Conjugative R-plasmid of facultative methylotrophic bacteria Pseudomonas sp. M]. / Kon''iugativnaia R-plazmida fakul'tativnykh metilotrofnykh bakterii Pseudomonas sp. M.

50 Md conjugative plasmid, designated pM3, has been found in the cells from natural isolates of Pseudomonas sp M. The plasmid determines the resistance to tetracycline and streptomycin and is capable of conjugative transfer between the cells of Pseudomonas and Escherichia coli. The conjugative derivatives of pM3 deleted for 14 Md of molecular mass were isolated after acridine dyes treatment of cells harbouring plasmid pM3. The discovered plasmid was not shown to belong to IncP1 incompatibility group.

[Preparation of protoplast-like structures of Pseudomonas putida and their reversion to bacterial forms]. / Poluchenie protoplastopodobnykh struktur Pseudomonas putida i ikh reversiiia v bakterial'nye formy.

A technique is proposed for the preparation of Pseudomonas putida protoplast-like structures by treating the cells with lysozyme in a hypertonic medium containing mono-and divalent cations. Pretreatment of the cells at the logarithmic growth phase with sucrose (0.5 M) for 90 min at the pH 7.9 to 8.0 is a prerequisite for the formation of 'protoplasts'. Under these conditions, the yield of 'protoplasts' reached 99.9% of the total cell number. The protoplast-like structures are capable of reversing into the original bacterial forms in a minimal hypertonic medium containing amino acids which are components of the cell wall. The level of reversion reaches 10% for certain strains.