Biomedical subjects
V V Babkov
Publications and source records attributed to V V Babkov.
[Study of the inactivation of antibiotics by bacterial colonies].
A procedure of bacteria application to disks from the colonies was used for determining antibiotic inactivation in the disks by the bacteria colonies after the disk direct contact with the colonies. Changes in the antibiotic activity in the disks were registered after incubation at 37 degrees C for 2 hours. It was shown that ampicillin resistant strains of E. coli K12 carrying R plasmids and strains of S. typhimurium and S. aureus inactivated the antibiotics in the disks and their population were homogenous in this respect. It is advisable to use the procedure in assaying drug resistance of bacterial populations.
[Immobilization of antibiotics on a titanium surface].
Immobilization of antibiotics on the surface of electrolytically oxidated titanium was tried. Transfer of the immobilized ampicillin into hardly soluble calcium ampicillate resulted in providing the coating with antimicrobial activity for 5 days. The quantity of the immobilized antibiotic determined polarographically amounted to 6.4.10(-3) mol per 1 m2 of the surface.
[Comparative characteristics of antigenic conversion induced by Shigella flexneri and Escherichia coli 0129 phages].
The interaction of S. flexneri converting phages PE5, P90 and fV with E. coli antigenic variant O129, E. coli O129 converting phage VB with the above antigenic variant and with S. flexneri y-variant was studied. Phage PE5 and phage VB were found to induce the conversion of O-antigen in E. coli antigenic variant 0129 and in S. flexneri y-variant with the detection of antigens V and 7,8. Phages P90 and fV induced no conversion of O-antigen. Changes in the antigenic properties of convertants were confirmed by the results obtained in the agglutination test and in the agglutination adsorption test.
[Formation of donor strains of enteropathogenic Escherichia serogroups 0112ac, 0129 and 0143 using RP4 plasmid].
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[Formation of donor strains of enteropathogenic Escherichia, serogroups O112ac, O129, O143, and Sh. boydii 8 using R-plasmids].
The possibility of the formation of enteropathogenic Escherichia and Shigella donor strains by means of R-plasmids RP4 and RPI-2 with thermosensitive replication was studied. The donor strains of E. coli, serogroups O112ac, O129, O143, and Sh. boydii 8 were thus obtained; these strains had the above-mentioned plasmids integrated into their chromosome, and in the process of conjugation they transferred plasmid and chromosomal genes to E. coli, K12 and O129, with the effectiveness 10(5)--10(8). Such donor strains may probably be used for studying the mechanisms of the formation of new enteropathogenic Escherichia and Shigella biovars and for their genetic analysis.
[Phage conversion of escherichia and shigella antigens. I. Phage conversion of type I antigen of Sh. flexneri in entrophatogenic E. coli O129].
The authors realized conversion of type I Sh. flexneri in enteropathogenic E. coli O129 with converting moderate phage phi I Sh. flexneri. Phage phi I lysogenized 7.3--42.7% of the cells of antigenic E. coli variant O129 which lost type V antigen; conversion of the type I antigen of Sh. flexneri was revealed in the agglutination and adsorption of agglutinins tests. As a result, E. coli strain was obtained with the O-antigen identical to the O-antigen of Sh. flexneri Ia.
[Phage conversion of the antigens in Escherichiae and Shigellae. 2. Conversion of the somatic antigen in Shigella flexneri with the moderate E. coli 0129 phage].
The authors studied the converting activity of the moderate EF5 phage isolated from the lysogenic E. coli 0129 strain. It was shown that this phage converted the O-antigen with the detection of the type antigen V in the strains of Sh. flexneri of the serological type la and y-variant. The converted cultures contained the type antigen V and were identical by the antigenic properties to one another and the Sh. flexneri of the serological type 5 and E. coli 0129. A conclusion was drawn that phages converting the antigens of Sh. flexneri could be encountered in escherichia and could modify the antigens in Sh. flexneri and escherichia possessing the antigenic factor 3,4.
[Biochemical and genetic characteristics of enteropathogenic Escherichia coli and Shigella. V. The biological properties of auxotrophic mutants of Shigella flexneri 2a and of Escherichia coli serogroup 0124:K72].
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[Some biological properties of E. coli 0124:K72(B17) cultures].
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[The theoretical-biological concept of N.K. Kol'tsov].
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[The colicin selection of the S forms of representatives in the Enterobacteriaceae family].
A method based on a lower sensitivity of S forms to colicines, in comparison with R forms, was used for the selection of S forms of bacteria from dissociated cultures of E. coli O.124:K72, S. sonnei, and S. flexneri. The cultures are inoculated in nutrient agar from the external segment of the zone of bacterial growth suppression by colicines D, E1, and V+m, where the content of S forms is relatively higher at the expense of death of R forms. The content of S forms in the resultant cultures of different strains was 1.7 to 31.1 times higher that in the initial cultures.