[Comparative analysis of the DNA of Corynebacterium diphtheriae phages and the cloning of the gene determining diphtheria toxin synthesis]. / Sravnitel'nyi analiz DNK fagov Corynebacterium diphtheriae i klonirovanie gena, determiniruiushchego sintez difteriinogo toksina.

The analysis of the DNA of one nontoxigenic C. diphtheriae phage and two toxigenic ones has revealed that phage phi 984tox+ belongs to omega-like tox+ phages, phage phi 9tox+ is a representative of a new group of phages and phage B (Freeman) tox is a deletion mutant of phage beta. The location of this deletion on the physical map of this phage has been established. To obtain the physical map of phage phi 984tox+, the complete library of internal DNA fragments has been constructed in vector pBR 322. The gene of native diphtheria toxin has been cloned in vectors pBR 322 and pUR 250. Plasmids pUR 250 with the inserts of the toxin gene have been shown to be unstable if tox and lac promoters are located in tandem before the body of the toxin gene. The prolonged cultivation of clones having such structure leads to the formation of a spontaneous mutation located in the region coding the C-end part of the A-fragment of the toxin.

[Immunodiagnosis of AIDS using preparations of the recombinant antigen of the surface protein of the HTLV-III virus]. / Immunodiagnostika SPID s pomoshch'iu preparatov rekombinantnogo antigena belka poverkhnosti virusa HTLV-III.

A technological scheme has been developed for purification of recombinant antigen of surface protein (ASP) of the causative virus of AIDS from Escherichia coli cells carrying plasmid pL2 which codes for the synthesis of a hybrid polypeptide consisting of phage lambda N protein (59 amino acid residues) and a fragment of SP (env) of HIV virus (569 a.r.). Purification of ASP is based on two separation principles: fractionation of polypeptides of bacterial lysates by preparative isoelectrofocusing in a granulated gel layer and the method of preparative polyacrylamide gel electrophoresis in "Multiphor" apparatus (Pharmacia). The ASP purified by these methods was used for construction of an immunodiagnostic preparation for AIDS, employing for this purpose solid-phase enzyme-immunoassay in two modifications: competitive sandwich method and analysis of the tested sera with direct sorption of ASP on nitrocellulose filters.

[Restriction analysis of the DNA of the toxigenic corynephages BF, phi 984, phi 9 and C]. / Restriktsionnyi analiz DNK toksigennykh korinefagov BF, fi 984, fi 9 i C.

The results of restriction analysis of toxigenic corynephages BF, phi 984, phi 9, and C are presented. Phage BF was shown to be a deletion derivative of phage beta vir, phage phi 984 to be omega-like. Toxigenic corynephages phi 9 and C belong to a new group of corynephages designated phi. DNA of phages phi 9 and C as well as chromosomal DNA of the indicator strains was not hydrolysed by specific Hind III endonuclease, that is likely to be associated with the presence of a modification system in host strains.

[Biological and physicochemical properties of Corynebacterium diphtheriae B (Freeman) phages phi 984 and phi 9]. / Biologicheskie i nekotorye fiziko-khimicheskie svoistva fagov Corynebacterium diphtheriae B (Freeman), fi 984 i fi 9.

A scheme for preparative isolation of corynephages and their DNA is described. Study of host specificity, toxigenicity, and of cytotoxic effect induced by the phages BF, phi 9, and phi 984 has shown that phage BF has tox- phenotype, and phages phi 9 and phi 984, tox+ phenotype. These phages differ in host specificity and plaque morphology. Electron-microscopic examination of virions showed similarity of phages BF and phi 984 structures, whereas phage phi 9 was markedly different in the size of its head and tail.

[Cloning and gene expression of the surface protein gene of the HTLV-III virus in E. coli]. / Klonirovanie i ékspressiia gena poverkhnostnogo belka virusa HTLV-III v E. coli.

A system has been developed for expression of surface protein (SP) of the virus of acquired immune deficiency syndrome (AIDS) in E. coli. For this purpose, cloning and substitution of a fragment of SP gene of HTLV-III virus under control of PL-promoter of phage lambda was carried out using pre-modified plasmid vector pPL-lambda. In the constructed plasmid pL2 1950 paranucleotides, the PvuII fragment of HTLV-III virus DNA is built-in in such a way that the frames of transcription of phage lambda protein N and SP of HTLV-III virus correspond to each other. As a result, plasmid pL2 codes for synthesis of a hybrid polypeptide consisting of phage lambda protein N (59 aminoacid residues--a. r.) and SP of HTLV-III (569 a. r.). The presence of the hybrid polypeptide in lysates of E. coli strains (K-12 delta H1 delta trp/pL2, M 5219/pL2, N 4830/pL2) was determined by solid-phase enzyme-immunoassay.

[Cloning in bacterial and yeast vectors of the hepatitis B virus genome]. / Klonirovanie v bakterial'nykh i drozhzhevykh vektorakh genoma virusa gepatita B.

Hepatitis B viral genome was cloned simultaneously with bacterial plasmides pBR 325 and pBR 322. Recombinant plasmides were constructed, containing DNA of hepatitis B virus as well as capable to replication in bacterial and yeast cells. Replication of one of these plasmides was possible if it integrated with chromosomal DNA of yeast target-cells; the other plasmides had a capacity to autonomous replication in yeast cells.