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Biomedical subjects

A S Tikhonenko

Publications and source records attributed to A S Tikhonenko.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[Electron microscopic study of intracellular growth of phage specific for Bacillus thuringiensis var. galleriae].

Ultrathin sections of Bacillus thuringiensis var. galleriae infected by a specific phage were studied by electron microscopy. Stages of the phage reproduction within the cell, from adsorption of phage particles to liberation of the phage from the cell, have been revealed. Growth of the phage follows that of DNA-containing phages. The yield of the phage is very high.

Adsorption↗
PubMedDate not supplied

Electron-microscopic study of the serological affinity between the antigenic components of phages T4 and DDVI.

In an investigation of the antigenic fine structure of phages T4 and DDVI with the use of the neutralization reaction and electron-microscopic observation of the phage-antibody complexes, it has been possible to establish that the head of phage T4 consists of proteins which have antigenic determinants of two types: The first type is identical to the antigens of the head of phage DDVI, and the second type is apparently absent in phage DDVI. The phage DDVI head contains mostly determinants which are common to the phage T4 head, since it was not possible to detect antigenically specific components in the phage DDVI head. The tail sheaths of phage T4 and DDVI appear to be identical in the antigenic respect. A difference has been observed in the fibers and the base plates of the phages investigated. The presence of the following three types of antigens has been established: 1) common to phages T2, T4, and DDVI, 2) common to phages T4 and DDVI, and 3) specific for each phage investigated.

Antigen-Antibody Complex↗
PubMedDate not supplied

[Electron microscope study of antigen constituents of the phage DDVI and its h-mutant].

A comparative study of the fine antigen structure of phage DDVI and its h mutant using neutralization reaction and the electron microscopy of the phage-antibody complex has shown that the head and the tail of these phages have common protein constituents. The bulk of the antigens located in tail's fibers and in a base plates is also identical. However, the application of the cross-adsorbed sera has shown that the phage DDVI and the h mutant differ by only one specific antigen located in the distal part of tail's fibers.

Antigens, Viral↗
PubMedDate not supplied

[Comparative study of moderate and virulent phages of mesophilous lactic acid streptococci].

A method has been developed to identify phage containing mesophilous lactic acid streptococci. The method is based on the chloroform treatment of young cultures. The isolated moderate phages P4St and P6St are morphologically identical and serologically related to one another and to virulent phages P1Sv, P2Sv, P3Sv, P12Sv, P13Sv that can be isolated in industrial phagolysis.

Bacteriophages↗
PubMedDate not supplied

[Self-assembly of extracellular tubular structures of non-protein nature produced by an actinomycete].

When grown on the solid synthetic medium with glucose as the only carbon source the dedifferentiated "fructose" mutant of Actinomyces roseoflavus var. roseofungini accumulated aggregates of tubular-like structures. The individual tubules had the internal diametre of 80 A and external diametre of approximately 200-220 A. These structures were isolated as a distinct fraction and their non-protein nature was demonstrated. They were easily soluble in acetone and reconstitutable in vitro. The possible significance of production of self-assembling structures by a mutant with impaired differentiation is discussed. The possibility of involvement of self-assembly processes in the formation of surface sheath of aerial mycelium in normally differentiating actinomycetes is mentioned.

Actinomyces↗
PubMedDate not supplied

[Immune electron microscopy in the study of biological matter].

A brief review of literature data and our investigations on the antibodies used for specific labeling in electron microscopy is presented. Considered are the problems connected with structure and function of separate components of bacterial viruses revealed by means of specific antibodies. The results of fine differentiation of antigenic components in the case of phages of the colidysentery group allowed to elucidate the functional role of the adsorption apparatus in the course of phage interaction with the bacterial cell. The topology of structural proteins (gene-products 35, 36, 37) of the tail's long strands for phages T4, DDVI+h and DDVIh is determined. Antigenic properties of proteins that are found in the composition of two forms of Bacillus mycoides are demonstrated immune-electronmicroscopically. On the basis of this finding, a conclusion was made that one of these phages acted as precursor, the other--as satellite during the simultaneous development of these phages in the bacterial cell. It was also established that temperate and virulent phages are related antigenically, which proves that lysogenic bacteria can be one of the phage sources on the environmental conditions. Visualization of non-ribosomal genes of procaryots that code for structural proteins of a defective phage proves the efficiency of the immune-electronmicroscopic method for investigating of biological objects.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Electron microscope study of changes in the chromatin structure in different functional states of nuclei of a ciliate Bursaria truncatella and a myxomycete Physarum polycephalum].

Chromatin structural organization was studied by means of electron microscopy in the macronuclei of ciliate Bursaria truncatella at various stages of the life cycle (at different time intervals after cell division, in resting cysts and at excysting) and in the nuclei of myxomycete Physarum polycephalum during the mitotic cycle. Inactive chromatin was shown to be organized in compact clumps 100-300 nm in diameter linked with each other, their loop organization being convincingly demonstrated. Upon activation chromatin decompacts and is represented by nucleosomal fibres with a lot of replicationally and transcriptionally active regions. Both the reptication and transcription processes in physarum nuclei and transcription processes in bursaria can occur on the loops of chromatin fibres emerging from the decompacting clump. The data obtained evidence in favour of a structural-functional correspondence between the chromatin clumps of physarum and bursaria and the chromomeres in chromosomes of higher eucaryotes. Based on the data received it is concluded that the chromatin clump represents a dynamic structure unit able to decompact forming the loop-shaped chromatin fibres. Such a structural organization provides the spacial distribution of DNA in the nuclei and the possibility of selective functioning of definite regions of the genome.

Animals↗