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V V Kravchenko

Publications and source records attributed to V V Kravchenko.

At least 55 records · Page 3Linked to original sources
PubMed1985

A simple and rapid method for sequencing DNA.

A simplified technique for DNA sequence analysis has been developed, based on modification of a previous method [(1980) Methods Enzymol. 65, 499-560]. It employs an adsorptive immobilization of terminally labelled DNA on DEAE paper followed by G, A+G, C+T and C specific modification and cleavage reactions. This solid-phase technique is faster and more convenient than the original method. The efficiency is comparable. The total processing time taken to produce cleaved fragments loaded on a gel is less than 2 h.

Autoradiography↗
PubMed1985

[A plasmid vector with temperature-controlled gene expression].

A 169 b.p. fragment including the bla gene promoter p3 has been removed from pBR327 plasmid, and the deleted plasmid used for cloning the TaqI/BglII-fragment of the lambda c1857ind- DNA containing promoter pR and gene cI to obtain plasmid pCE119. Cells containing pCE119 produced a high level of beta-lactamase at 42 degrees C, the yield at 42 degrees C being 100 times higher than at 32 degrees C. For cloning and functional assays a pCEZ12 plasmid was constructed, in which promoter pR and repressor cI of lambda phage control the expression of the semi-synthetic beta-galactosidase gene. Yield of beta-galactosidase produced by pCEZ12 at 42 degrees C was ca. 300 times higher than at 32 degrees C.

Bacteriophage lambda↗
PubMed1984

[Synthesis of a 33-member polynucleotide containing the "core" att site of phage lambda DNA and its cloning].

Two polynucleotides containing 33 monomeric units were synthesized by a solid-phase phosphotriester method. These polynucleotides form a duplex with protruding 5'-ends, which allows to clone the duplex in EcoRI site of a cloning vehicle. Each polynucleotide was purified by electrophoresis in polyacrylamide gel, and the duplex obtained was cloned in EcoRI site of pUR 222 plasmid DNA. The structure of the cloned duplex containing the "core" att site of phage lambda was confirmed by sequencing.

Bacteriophage lambda↗
PubMed1983

[A solid phase method of determining DNA sequence].

A solid-phase method for DNA sequencing has been developed which involves immobilization of the terminally labeled DNA fragment on the DEAE-paper followed by chemical modification and cleavage at G, A + G, C + T, and C sites. As compared to the Maxam and Gilbert method, the new technique is more rapid and less laborious, being of the same efficiency.

Base Sequence↗
PubMed1979

A rightward promoter to the left of the att site of lambda phage DNA: possible participant in site-specific recombination.

The binding has been studied of Escherichia coli RNA-polymerase to the fragments of lambda DNA obtained by digestion with restriction endonucleases BsuI, HindIII, BamHI, EcoRI and HindII + III. There are at least six sites of RNA-polymerase binding in the b2-region. In vitro transcription of those BsuI-fragments of the b2-region which contain six binding sites is rightward. Therefore, the fragments contain promoters rather than mere RNA-polymerase binding sites. One of the promoters of the b2 region named patt was calculated to be about 50 bp to the left of the att site. We postulate that this promoter might correspond to the hef-target which was described as important for the site-specific recombination.

Bacteriophage lambda↗
PubMedDate not supplied

[Structural modification of environment by microorganisms: formation of Liesegang rings around Dictyostelium discoideum population].

The results of the experimental study of the environment modification--the emergence of Liesegang rings around a Dictyostelium discoideum population are presented. The formation of Liesegang rings induced by D. discoideum cells is observed on addition of glucose into the semi-solid nutrient medium (agar concentration 0.5-1.5%). We show that the emergence of Liesegang rings is attended with a redistribution of folic acid in the nutrient substrate. A pH decrease in the course of D. discoideum cultivation is shown to be a factor inducing the redistribution of folic acid. The mechanisms of structural modification of the D. discoideum environment are discussed.

Agar↗