[Reaction between isolated lambda phage DNA and membrane structures of Escherichia coli cells]. / Vzaimodeistvie izolirovannoi DNK faga lambda s membrannymi strukturami kletok Escherichia coli.

The saccharose density gradient (30--55%) centrifugation technique applied to E. coli membrane preparations was used to show that treatment of the bacteria with Ca2+ in the cold results in the redistribution of the absorbed phage DNA from the cell wall to the cytoplasmic membrane while freezing-thawing of the bacteria leads to equal distribution of the infectious DNA among all membrane fractions. Quantitative estimation of such a redistribution is reported.

[Study of the stimulating action of sturin, its fractions, and the internal protein of T2 phage in transfection of E. coli spheroplasts by Lambda phage DNA]. / Issledovanie stimuliruiushchego deistviia sturina, ego fraktsii i vnutrennego belka faga T2 v transfektsii sferoplastov E. coli DNK faga lambda.

The stimulating action of sturin and its fractions in the transfection of E. coli spheroplasts with DNA of phage lambda has been shown, and the optimum conditions for the infection of sturin-treated spheroplasts with phage DNa have been established. The biological effect was most pronounced in arginine-enriched low-molecular sturin fraction B. The treatment of spheroplasts with the internal protein of phage T2 did not stimulate transfection. These findings suggest that the specificity of the stimulating action of protamine depends on the peculiarities of its amino acid composition, viz. a high content of arginine which is present in protein molecules in the form of blocks made up of 2-6 amino acid residues.

[Adsorption of lambda phage DNA onto Escherichia coli cells treated with Ca2+ ions and onto frozen--thawed bacteria]. / Adsorbtsiia DNK faga lambda na kletkakh Escherichia coli, obrabotannykh ionami Ca2+, i na zamorozhennykh-ottaiannykh bakteriiakh.

The study of the biologically active tritium-labeled phage lambda DNA adosrption on Ca2+-treated and frozen--thawed E. coli cells showed the absence of a correlation between the adsorption level and transfection efficiency. Thus the infectious phage lambda DNA adsorption level does not change, while frozing--thawing of E. coli cells but it increases ten-fold when treating the cells with Ca2+ in ice, the transfection efficiency level with this DNA being equal for both types of recipients.

[Interaction between a fluorescent probe and the surface structures of Escherichia coli]. / Issledovanie vzaimodeistviia fluorestsentnogo zonda s poverkhnostnymi strukturami Escherichia coli.

The interaction of ANS with Escherichia coli cells, isolated cell walls, total cell envelopes and inner membranes was investigated in the presence and absence of Ca2+ ions. The addition of Ca2+ to intact cells at room temperature did not result in enhancement of fluorescence intensity. On the contrary the addition of Ca2+ to intact cells at 2 degrees C resulted in a progressive increase of fluorescence intensity with the maximum reached approximately by the 20th minute. The addition of Ca2+ to different membrane preparations showed a two-fold increase. Addition of Ca2+ to spheroplast membrane preparations did not result in any increase of the number of binding sites for ANS. There was a four-fold increase in quantum yields. All membrane preparations in titrations with Ca2+ showed saturation kinetics. The obtained results are discussed in terms of structural alterations in E. coli membranes and in relation with biological effects.

[Interaction of the isolated DNA of lambda phage with spheroplasts of E. coli treated with sturine]. / O vzaimodeistvii izolirovannoi DNK faga lambda so sferoplastami E. coli, obrabotannymi sturinom.

The method of centrifugation in sucrose density gradient (30-55%) of the spheroplast membrane preparations treated and untreated with sturine and infected with phage lambda DNA demonstrated that sturine, treatment increased the phage lambda DNA absorption three-fold. About 50% of the lambda DNA molecules adsorbed by spheroplasts are bound with the cytoplasmic membrane of spheroplasts treated with sturine; 50% of the lambda DNA molecules are bound with the cell wall membrane on the sturine-untreated spheroplasts. The data obtained allow to conclude that the stimulating effect of sturine in E. coli spheroplasts transfection by lambda DNA is connected with redistribution of phage DNA absorbed on spheroplasts from the cell wall to the cytoplasmic membrane facilitating the penetration of DNA and its fastening on the membrane.

[Mechanism of the stimulating effect of protamines on the infectivity of DNA phages]. / K mekhanizmu stimuliruiushchego deistviia protaminov na infektsioznost' DNK fagov

The interaction of styrin (protamine from sturgeon milt) with E. coli spheroplasts was investigated with the aid of the fluorescent probe--5-dimethylamino-1-naphthalenesulfonyl-chloride (DNS). Not less than 40% of the total (15 mug ml-1) DNA-protamine concentration was bound to spheroplasts. A part of the protein was found in the isolated membranes and inside the cell. There was a correlation between the binding of protein with spheroplasts and its biological action. The dansylation somehow decreased the protein stimulating activity in transfection.