Search PubMed⌕ Search

Biomedical subjects

L N Kats

Publications and source records attributed to L N Kats.

At least 19 recordsLinked to original sources
PubMed1988

[Isolation and ultrastructure of Yersinia spheroplasts and protoplasts].

The conditions suitable for the cultivation of Yersinia and the inhibition of their cell-wall synthesis have been selected with the aim of obtaining spheroplasts and protoplasts of these microorganisms. Penicillin, streptomycin and lithium chloride have proved to be not very suitable for this purpose as they induce essential changes in the structure of the cytoplasmic membrane in altered Yersinia forms. The addition of 1% of glycine (for Y. pseudotuberculosis), 1-1.5% of methionine in combination with growth stimulators has made it possible to obtain Yersinia spheroplasts and protoplasts with the intact cytoplasmic membrane, thus permitting the isolation and purification of the cytoplasmic membrane fraction.

Bacteriological Techniques↗
PubMed1987

[Ultrastructure of Staphylococcus in disruption of the integrity of the cell wall].

The effects of penicillin, lithium chloride and homologous antiserum with complement on S. aureus after a single exposure to these agents and in subsequent subculturing were studied. The viability of the altered forms obtained in these experiments was evaluated by the number of colony-forming units per ml. The action of all above-mentioned agents resulted in the appearance of staphylococcal forms with the altered cell wall. The lesions in the submicroscopic organization of the cell wall, produced by the action of the above-mentioned agents, differed in the appearance of porosity and ruptures in the wall under the action of penicillin and antiserum, thinning and peeling-off of the wall under the action of lithium chloride. The damage of the cell wall is accompanied by the disorganized septal development and mitosis, and sometimes by the formation of elementary bodies in the cytoplasm.

Cell Wall↗
PubMed1987

[Ultrastructure of the L forms of Streptococcus group B].

The submicroscopic organization of the L-forms of beta-hemolytic streptococci of group B has been studied in the course of their cultivation. The L-forms of group B streptococci differ from those of group A streptococci by a higher growth rate. On the submicroscopic level, the activity of ATP-ase has been revealed on the internal side of the cytoplasmic membrane. Regularities in the localization of intramembranous particles sized 6-18 nm in the hydrophobic area of the membrane have been established by means of freezing-etching. With the adequate methods of fixation, the continuous three-layer structure of the cytoplasmic membrane can be determined in all elements of the L-form population.

Adenosine Triphosphatases↗
PubMed1986

[Comparative biological characteristics of the L-form of Streptococcus group A and B].

The comparative study of the biological and serological properties of the L-forms of streptococci, groups A and B, has been made. Their morphological similarity on the level of light microscopy has been demonstrated. The use of ring precipitation, gel diffusion, passive hemagglutination, aggregate hemagglutination, as well as the immunoferritin technique, has made it possible to establish the presence of specific antigens in the L-forms of streptococci, groups A and B. Serological cross reactions are negligible. The future development of a diagnosticum for the specific indication of these antigens is proposed. The fact of the presence of specific antigens in the L-forms of streptococci in comparison with the initial streptococcal strains has been confirmed.

Antigens, Bacterial↗
PubMed1985

[Isolation of unbalanced growth forms from Listeria and their ultrastructure].

As the result of the action of penicillin, LiCl and UV irradiation on Listeria culture in the logarithmic phase, unbalanced growth forms (UGF) were obtained. Their viability was determined by the number of colony-forming units per ml. In this investigation the action of the above factors in a single cultivation and in consecutive subcultures was studied. Viable UGF were obtained under the action of all the above factors. UGF obtained under the action of penicillin were found to convert easily into L-forms in the process of subculturing. On the contrary, UGF obtained under the action of UV irradiation and LiCl produced no L-forms and reverted easily when the action of these factors stopped. In all three cases the formation of UGF was accompanied by changes in the structure of the cell wall and, partially, the cytoplasmic membrane, but in each case these changes had different character.

Cell Division↗
PubMed1984

[Ultrastructure of the unbalanced growth forms of Salmonellae obtained by the action of various factors].

The unbalanced growth forms (UGF), also known as heteromorphous or pleomorphous forms, of salmonellae were obtained under the action of penicillin, homologous antiserum in combination with complement and lysozyme, as well as ultraviolet radiation. The effect of these factors was studied after their momentaneous action and in successive passages. The viability of UGF was determined in terms of colony-forming units. The appearance of UGF was induced by penicillin, a complex of immune substances and ultraviolet radiation, yet the action of two latter factors irreparably damaged most of the cells. The formation of UGF, showing stability in prolonged passages and capable of transformation into L-forms, occurred only under the influence of penicillin. Elementary bodies appeared in UGF, both capable and incapable of transformation into L-forms after successive passages. In the viable part of the UGF population obtained under the action of all the above factors damages in the peptidoglycan layer of the cell wall and, partly, in the cytoplasmic membrane, as well as disturbances in the process of cell division, linked with these cell elements, were observed.

Complement System Proteins↗
PubMed1983

[Antigenic characteristics of the L forms of Streptococcus group B].

Stable L-forms of group B streptococci (GBS) have been obtained and their antigenic features have been studied by the serological methods (the passive hemagglutination test, the aggregate agglutination test, the gel diffusion test), as well as by using ferritin and peroxidase labels with the subsequent electron microscopy. The use of the serological methods has made it possible to reveal the antigenic differences between the stable L-forms of GBS and their bacterial forms. Specific antigenic substances can be found in the supernatant fluid obtained after the sedimentation of the ultrasonically disintegrated cellular mass of streptococcal L-forms and bacterial cultures. The use of ferritin and peroxidase labels has revealed the specificity of GBS L-form antigen and its localization on the cytoplasmic membrane of all L-form structural elements.

Animals↗
PubMed1983

[Ultrastructure of Salmonella typhimurium forms with unbalanced growth induced by lithium chloride].

The action of 1.0 and 1.5 M LiCl on S. typhimurium induces the appearance of unbalanced growth forms capable of growing and multiplication, when subcultured in a medium with this preparation. In this culture the prevalence of cells differing in their structure from the initial Salmonella cells and from stable L-form cultures is observed. Cells characteristic of the initial culture and cells resembling the L-forms occur in lesser numbers. LiCl seems to affect peptidoglycan and the cytoplasmic membrane, which brings about disturbances in the permeability of the surface structures of the cell.

Chlorides↗
PubMed1982

[Modes of the formation of elementary bodies and their isolation from the cell in L-form bacteria].

Elementary bodies are formed on the cell surface and inside the cell body in all cell types characteristic of L-form cultures, i. e. spherical cells, large bodies and filament structures. The following ways of elementary body formation are described: by budding on the cell surface, appearance immediately in the cytoplasm, in the vacuole, as a result of cytoplasmic fragmentation accompanied by the lysis of the cell, as well as in cases of the separation of cytoplasmic areas surrounded by the membrane or the myelin-like structure. The release of elementary bodies from the cell occurs as a result of the lysis or death of the mother cell, the thinning of the vacuole wall, and possibly due to small transient defects in the membrane, not accompanied by the death of the mother cell. The scheme of the formation and release of elementary bodies from the cell is presented.

Bacillus subtilis↗
PubMed1982

[Antigen localization in Streptococcus group A, L forms and revertant by an immunoferritin method].

The comparative study of antigen localization in the initial streptococcus, in its stable L-forms and in the revertant obtained from the L-forms in early L-transformation passages. has been carried out. In this study 3 sera were used in homologous and heterologous reactions Ferritin-labeled homologous antibodies have been shown to localize directly on the cell-wall surface in the initial strain and in the capsule-like slime in the revertant. The L-forms have been found to possess some membrane-localized antigens in common with the revertant and, to a lesser extent, with the initial streptococcal strain.

Antibodies, Bacterial↗
PubMed1981

[Structural features of the elementary bodies of bacterial L-forms].

Elementary bodies have been detected in the L-forms of various bacteria, irrespective of their strain, the phase of development and stabilization of their culture. Elementary bodies have been found to have all organoids peculiar to other L-culture cells (the unit membrane, the nucleoid, ribosomes, more seldom mesosome-like structures and the outer membrane of the cell wall), which is indirectly indicative of their possible viability. The cytoplasmic membrane of elementary bodies contains dehydrogenases (detected in the NBT test), has the hydrophobic layer structure typical of bacterial membranes and, judging by the results of the ferritin test, possesses the same antigenic properties as the cytoplasmic membrane of other L-culture cells. Nevertheless, the above-mentioned properties are far from being the attribute of every elementary body, and the completeness of their manifestation is not directly related with the size of elementary bodies.

Cell Membrane↗
PubMed1980

[Utilization of a method of growing microorganisms on millipore filters in order to study their structure with a scanning electron microscope].

A comparative study of bacteria and their L-forms Actinomyces and blue-green algae, taken from centrifugates and grown on Millipore filters, was made with the use of scanning electron microscopy. The study revealed that only in the second case the location of the cells inside the colony was preserved and the architectonics of the colony remained unchanged. The anastomoses between the cells and slime on the cell surface, destroyed when other methods of making the preparations were used, could be easily detected.

Bacteria↗
PubMed1979

[Cell structure and the pathogenicity of Brucella at different stages of L transformation].

On the basis of changes in the biological properties and morphology of Br. abortus culture under the action of penicillin 3 stages of L-transformation in Brucella were determined. The prevalence of first bacilliform and then typical L-cells and rapid reversion hampering the determination of virulence were characteristic of the initial stage (passages 1-4). Typical L-cells with the wrinkled surface, deep depressions and holes as well as a decrease in virulence and slight pathomorphological changes in the organs of the infected animals were characteristics of the intermediate stage (passages 5-10). Typical L-cells and amorphous masses, a further decrease in virulence, pathomorphological changes of toxic character (only after the injection of L-culture in large doses) were characteristic of the late stage (from passage 11 and further on). At all stages of L-transformation Brucella cultures showed a high reproductive capacity, binary division, the formation of elementary bodies by budding both inside and on the surface of L-cells.

Animals↗
PubMed1979

[Population of L-forms of Bacillus subtilis studied in Ficoll density gradients].

The distribution of cells in the population of L-forms of Bas. subtilis was analysed by isopicnic centrifugation in density gradient of ficoll. Two main fractions of L-forms different in their density were found. The study of the fractions by various methods indicated that a considerable part of the L-forms population is presented by unviable cells of diverse size with fragments of genome or without DNA.

Bacillus subtilis↗