[Use of diagnostic DNA probes for detection of the provirus of bovine leukemia virus in infected cows]. / Ispol'zovanie diagnosticheskikh DNK-zondov dlia obnaruzheniia provirusa virusa bych'ego leikoza u infitsirovannykh korov.

A method of detection of BLV proviral DNA in the peripheral blood leukocytes of cattle is reported. Leukocytes were used without preliminary cultivation. Cell DNA was dot-hybridized with P-labeled plasmid containing a fragment of BLV proviral DNA. The sera samples taken from the cattle under study were also tested using immunodiffusion assay (ID). The results of comparison showed that dot-hybridization assay is a more sensitive diagnostic test than ID, because it detects BLV infection in apparently normal cattle, which was seronegative in ID.

[Restriction analysis of the DNA of aleutian mink disease virus strain P-1]. / Restriktsionnyi analiz DNK virusa aleutskoi bolezni norok shtamm P-1.

The II-1 strain of the Aleutian disease virus (ADV-II-1) was isolated from experimentally infected mink organs. The viral particles were isolated having 23 to 24 nm in diameter with the buoyant density of the virions in CsCl gradient being 1.41 g.ml-1. The single stranded ADV DNA extracted from the purified virus particles had the molecular mass about 1.4 . 10(6) (4800 bases). The double-stranded replicative form of ADV DNA has been synthesized in vitro with the use of a large "Klenow" fragment of DNA-polymerase I. A restriction endonuclease map of ADV-II-1 DNA has been constructed with the use of in vitro synthesized double-stranded DNA.

[Comparison of methods of detection of bovine adenovirus serotype 3 in infected culture of calf kidney cells (MDBK)]. / Sopostavlenie metodov obnaruzheniia adenovirusa krupnogo rogatogo skota 3-go serotipa v zarazhennoi kul'ture perevivaemykh kletok pochki telenka (MDBK).

The comparative study of the dynamics of the main antigen (hexon) and viral DNA of the bovine adenovirus type 3 accumulation in the established cell line MDBK under the conditions of single- or multistep cycle of infection has been undertaken. The quantitative immunoelectrophoresis and immunoenzyme assay detected the viral antigens on the late stages of infection in the period of cellular monolayer degradation. The immunofluorescence reaction and histochemical immunoenzyme method detected the antigen in the infected cells concurrently with the primary expression of the viral cytopathic effect. The reaction of the spot molecular hybridization with the [32P]-DNA probes detected the viral DNA considerably earlier than the antigen was detected by the immunological methods, before the appearance of degenerative changes in the infected cells. Preference of the immunoenzyme assay and DNA-probes in diagnosis of the virus are discussed.

[Nucleotide sequence of the cDNA of kappa casein in cows]. / Analiz nukleotidnoi posledovatel'nosti kDNK kappa-kazeina korovy.

Nucleotide sequence of the cloned DNA complementary to cow kappa-casein mRNA was determined. The complete sequence is composed of 854 bases and includes 60 bases of 5'-noncoding region, 570 bases of the coding region and 209 bases of 3'-noncoding region without poly(A). The cloned sequence codes for kappa-casein, the genetic variant B2. Several restriction sites were defined that permitted the identification of genetic variants and size polymorphism of restriction fragments in the structural region of the gene. Upon the comparative analysis of kappa-casein mRNAs of cow and rat, it was shown that, apart from functionally important regions in the coding sequence, high homology is characteristic of the 5'- and 3'-noncoding regions.

[Synthesis and cloning of DNA complementary to mRNA of the bovine mammary gland]. / Sintez i klonirovanie DNK, komplementarnykh mRNK molochnoi zhelezy korovy.

Poly(A+)mRNA from bovine mammary glands was used to synthesize double-stranded cDNAs that were subsequently inserted into the plasmid vector pBR322 at the Pst1 site by means of oligo(dG)-oligo(dC) tailing. After transfection of Escherichia coli JC5183, recombinant plasmid library containing 5400 clones was screened by serial rounds of colony hybridization in situ to total [23P] poly(A+)mRNA and electrophoretically homogenious [32P]16SmRNA of mammary glands. Then hybrid selection of mRNA and subsequent in vitro translation of selected mRNAs were performed. In this manner, recombinant clones coding for alpha S1- beta-, kappa-casein were identified. cDNA clones range in size from 35% for beta-casein, 65% for alpha S1-casein to about 95% for kappa-casein, in comparison with their respective mRNAs.

[Isolation and properties of DNA polymerase from the extreme thermophilic bacterium Thermus ruber]. / Vydelenie i svoistva DNK-polimerazy iz ekstremal'no-termofil'noi bakterii Thermus ruber.

A DNA-polymerase from the external thermophylic bacteria Thermus ruber has been isolated. A six-step purification procedure resulted in an electrophoretically homogeneous enzyme preparation with m. w. of 70 000. The isolated enzyme is thermostable and has a temperature optimum on DNA templates at 70 degrees and that on RNA templates at 50 degrees. The enzyme does not contain contaminant endo- and exonuclease activities. The maximal activity of the enzyme requires the presence of template, four deoxyribonucleoside triphosphates, monovalent and divalent cations in the incubation mixture. The catalytic activity of the enzyme on various templates of DNA- and RNA-types has been investigated. A comparative physico-chemical study of this DNA-polymerase and an analogous enzyme isolated earlier from the external thermophylic bacteria Thermus aquaticus YT-1 has been carried out.

[Isolation and properties of DNA-polymerase from the extreme thermophilic bacterium Thermus flavus]. / Vydelenie i svoistva DNK-polimerazy iz ékstremal'no-termofil'noi bakterii Thermus flavus.

A DNA-polymerase from the extreme thermophilic bacteria Thermus flavus has been isolated. The five-step purification procedure resulted in an electrophoretically homogeneous enzyme with molecular weight of 66000. The isolated enzyme is thermostable and a temperature optimum on the DNA templates at 70 degrees and that on RNA templates at 50 degrees. The enzyme does not contain contaminant endo- and exonuclease activities. The maximal activity of the enzyme requires the presence of template, four deoxyribonucleoside triphosphates and monovalent and bivalent cations in the incubation mixture. The enzyme is highly active when "activated" DNA, poly(dA)-poly(dT), poly(dA)-oligo(dT) 10 and poly(rA)-oligo(dT)10 are used as templates, moderately active on single-stranded and double-stranded DNAs and inactive on poly(rC)-oligo(dG)12-18 and native RNA molecules.

[Isolation and properties of DNA polymerase from extreme thermophylic bacteria Thermus aquaticus YT-1]. / Vydelenie i svoistva DNK-polimerazy is ekstremal'no-termofil'noi bakterii Thermus Aquaticus YT1.

A DNA polymerase has been isolated from the thermophylic bacteria Thermus aquaticus YT-1. The six-step purification procedure resulted in an electrophoretically homogeneous enzyme preparation with molecular weight of about 62 000. The enzyme does not contain contaminant exo- and endonuclease activities and has a temperature optimum on the DNA templates at 70 degress and that on RNA matrices at 50 degrees. The maximal activity of the enzyme requires the presence of bivalent cations (magnesium or manganese) 0,1--0,2 M KCl or NaCl, all deoxynucleoside triphosphates and template in the incubation mixture. The enzyme is active when "activated" DNA, poly(dA)-poly(dT), poly(dA)-oligo(dT)10 and poly(rA)-oligo(dT)10 are used as templates and is inactive on the native and denaturated DNAs as well as on the native molecules of RNA and poly(rC)-oligo(dG)12--180.