[Role of prophages in the formation of antibiotic-resistant populations of Staphylococcus in the process of transformation, transduction and conjugation].
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Conjugation, Genetic↗
Biomedical subjects
N V Klitsunova
Publications and source records attributed to N V Klitsunova.
[Polymorphism of virus-like particles of retrotransposons in Drosophila and yeast cells].
Data on the molecular arrangement of viruslike particles (VLPs) of yeast and Drosophila retrotransposons are presented. Two methods for identifying VLPs from specific retrotransposon families have been offered. The first method is based on VLPs fractionation by electrophoresis in agarose gel under strictly controlled conditions. VLPs of the Drosophila melanogaster retrotransposon families copia and gypsy and D. virilis retrotransposon Tv1 were identified by this method. The method based on heterologous induction of retrotransposons in cells of the mutant spt3 strain of Saccharomyces cerevisiae was used to identify VLPs of yeast retrotransposon Tyl and D. melanogaster gypsy retrotransposon.
Animals↗
Genetic and molecular R-plasmid analysis of Enterobacteriaceae hospital strains at Children's Hospitals of the former USSR.
R-plasmids from Enterobacteriaceae clinical strains, mainly Klebsiella and Serratia, isolated at different neonatal and children's hospitals of different cities of the former USSR for 10 years, were studied for their possible influence on the bacterial host phenotype. Hospital R-plasmids of stable inheritance persisted in hospitals from 2 to 7 years and were disseminated among strains of different genera (Klebsiella, Serratia, Enterobacter) and among different units. The data showed a possibility of long-term molecular rearrangements of R-plasmids in the hospital settings and an acquisition of genetic determinants encoding enterotoxin production. A novel R-plasmid encoding cytotoxicity to HEp-2 cells involved in two nosocomial outbreaks due to K. pneumoniae strains was reported. K. pneumoniae population heterogeneity was evaluated by using the plasmid parameters of strains. Their heterogeneity of a bacterial population was significantly lower during nosocomial outbreaks than in interepidemic periods.
Base Sequence↗
[Identification and ultrastructural characteristics of retrotransposon Tv1 virus-like particles in Drosophila virilis cells].
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Animals↗
Mixed Rickettsia-virus infection in Dermacentor reticulatus imago.
Electron microscopic examination revealed replication and accumulation of Rickettsia sibirica in the fat body of experimentally infected Dermacentor reticulatus ticks. Rickettsia are released from the fat body cells by budding being surrounded with cytoplasm and plasmalemma of the host cell. Eukaryotic cell structures have been detected consisting of lamella layers whirled around the intact rickettsiae. In addition to rickettsia, microorganisms morphologically resembling Francisella tularensis and an orbivirus were found in tick tissues at morphological examination. The morphology of the virus and stages of its morphogenesis are described. Mixed viral and rickettsial infection has been shown to develop in the same ticks and even in the same fat body cells in a very close association.
Animals↗
[The effect of interferon preparations on the ultrastructural organization of Legionella pneumophila].
The influence of the preparations of interferon on morphological changes in L. pneumophila on the ultrastructural level has been studied. Disturbances in the ultrastructure of L. pneumophila result from the direct bactericidal action of interferons without any interference of immune mechanisms. These disturbances are manifested by damages in the cell wall, plasma membrane, nuclear and ribosomal apparatuses of microbial cells. Leukinferon exhibits pronounced anti-Legionella activity, both in vitro in a liquid culture medium and in ovo, than reaferon.
Animals↗
[The ultrastructure of the interaction of Rickettsia sibirica and R. slovaca with the cells of ixodid ticks].
The ultrastructural aspects of the interaction of R. sibirica and R. slovaca with cells of mites of the species Dermacentor reticulatus, D. marginatus and Ixodes ricinus after their parenteral infection, as well as in the organs of D. marginatus infected naturally in the environment, have been studied. Both rickettsial species have similar morphology in different organs of the vector. These rickettsiae not only multiply, their populations are also partly destroyed in phagolysosomes. The natural mixed infection of R. sibirica and orbivirus in cells of D. reticulatus is described. As shown in this study, both associates pass through the complete ontogenetic cycle of development on the level of the host body and also on the level of an individual cell.
Animals↗
[The interaction of Legionella pneumophila with different types of cell cultures and the effect of interferon preparations on this process].
The interaction of L. pneumophila with lymphoblastoid cell cultures H9 and H9/IIIB and epithelial cell cultures HEp-2 mutual influence have been noted. L. pneumophila penetrates into cells HEp-2 and multiplies there due the so-called "spin phagocytosis". The study of the influence of the preparations of interferon, Leukinferon and Reaferon, on the adhesive capacity of bacteria and their penetration into eukaryotic cells has revealed that the preliminary treatment of both bacteria and cells HEp-2 with the preparations of interferon prior to their infection with Legionella leads to a decrease in the number of microorganisms associated with cells.
Bacterial Adhesion↗
[The determination of the location of basic protein I in the Rickettsia prowazekii cell].
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Animals↗
[The surface antigens of Rickettsia prowazekii studied with monoclonal antibodies].
R. prowazekii antigens have been tested with the use of monoclonal antibodies (McAb) to different epitopes of the microorganism. As revealed in these tests, McAb B4/4 and A-3/D, active against species-specific thermolabile antigen, interact with protein having a molecular weight of 90-120 KD. McAb C5/2, active against thermostable group antigen common with that of Rickettsia typhi, interact with LPS-like antigen having a molecular weight of 30 KD. Ultrastructural immunochemical studies have revealed that both R. prowazekii antigens are located on surface structures of rickettsiae, such as the microcapsule and cell wall.
Antibodies, Monoclonal↗
[Change in the ultrastructure of the cell wall of Bacillus cereus, determined by RP4 MUCTS62 plasmid].
The influence of plasmid RP4 Mucts62, heterologous for B. cereus, on the growth rate of B. cereus strains GA 682 and 319 obtained in our earlier experiments and on changes in the ultrastructure of their cell walls in comparison with B. cereus initial strains GP 7 and DSM 318 has been studied. Plasmid RP4 Mucts62 with a wide spectrum of action has been found not only to determine the functional signs of resistance to antibiotics and thermal sensitivity in the heterologous host, but also to take part in the morphological organization of the cell surface structure, and in particular in the structure of the S-layer. B. cereus strains containing plasmid RP4 Mucts62 are characterized by slower growth rate and cell fragility.
Bacillus cereus↗
[Adhesion in meningococcus].
The adhesive activity of 113 meningococcal strains with different invasive properties and 10 Neisseria nonpathogenic strains have been studied. Adhesive properties have been revealed in 80-82% of these strains. Meningococcal strains isolated from the nasopharynx of carriers possess high hemagglutinating activity. The percentage of cells with pili in these strain was also higher than that in meningococcal strains isolated from the liquor of patients. This shows the presence of direct correlation between the number of pili in the cells (according to the data of electron microscopy) and their activity in the hemagglutination test, which makes it possible to use this test for the determination of the adhesive capacity of meningococci, associated with the presence of pili.
Animals↗
[The morphological characteristics of the chondriome of human lymphoblastoid cells producing the human immunodeficiency virus].
The mitochondrial complex condition of continuous CEMT4 cell line infected by the human immunodeficiency virus has been investigated. The mitochondrial morphology of these and of intact cells was similar in great extent, though several changes were observed. For example, mitochondrial profiles with multiple dichotomous branches and anastomosis cristae were noted in the former. These changes resulted in the augmentation of the inner membrane square of mitochondrion. The formation of mitochondrial clusters connected with special junctions was a very characteristic part of the infected cell. Contacts were seen to be formed between the outer membranes neighboring profiles. These contacts look as X-like little bridges, or net-like or plate-like structures. The mutual transition of all these structures was observed using goniometer adapter. As has been shown by the three-dimensional reconstruction of mitochondrial junction zones, this area is presented by a single mitochondrion being structurally very complicated and very large in size compared to the neighbouring ones.
Cell Line↗
[The adhesive properties of a nonenteropathogenic strain of Escherichia coli in systems in vitro on isolated rat enterocytes and in vivo].
The adhesive properties and colonizing capacity of E. coli strain O83, isolated from feces of healthy humans and marked according to its resistance to rifampicin and nalidixic acid, were studied. In vivo experiments on germ-free rats revealed that these bacteria were capable of colonizing intestinal mucosa; colonization increased from the small to large intestine and E. coli cells were mainly concentrated in the intestinal lumen and in mucin. In vitro studies showed that this nonenteropathogenic E. coli strain possessed pronounced adhesive properties with respect to the colonic cells of germ-free rats; these properties were considerably less pronounced with respect to the enteric cells of the small intestine. The electron microscopic study of E. coli cells revealed the presence of fimbriae and fibrillae on their surface.
Animals↗
[Interaction of Neisseria meningitidis with eukaryotic cells in a mixed infection in vitro].
To study the adhesion of meningococci under the conditions of a monoinfection and mixed infection (in association with influenza virus), the experimental model of mixed influenzal and meningococcal infection has been created in the culture of epithelial cells HEp-2. On this model in increase in the intensity of the adhesion of meningococci to eukaryotic cells, as well as in the intensity of the meningococcal colonization of such cells, after their preliminary infection with influenza virus has been observed. The study has revealed that in mixed infection the adsorption of extracellular virions onto the surface of bacteria occurs. During this adsorption viral processes directly interact with the microcapsule of the meningococcus.
Adsorption↗
[Ultrastructural aspects of the process of Salmonella typhi bacterial interaction with L929-line cells].
The study of the use of scanning electron microscopy and the analysis of the initial stages of interaction between S. typhi and eukaryotic cells by the method of three-dimensional reconstruction has revealed that the infective agent penetrates into the cytoplasm on the principle of internalization. The internalization of S. typhi occurs with the active participation of the eukaryotic cells which, at the beginning, envelopes the bacteria with its processes, and the infective agents firmly adhere to the glycocalyx of the host cell by means of special fimbria-like formations differing from fimbriae by their lesser rigidity and thickness; then the microbes fixed to the membrane penetrate inside the cell without destroying its cytoplasmic membrane. Differences in the processes of the interaction of eukaryotic cells with S. typhi initial strain 238 and its variant free from the plasmid with a molecular weight of 6 Md, characterized by its lower capacity for association with cells of continuous cell culture L929, have been revealed. The factors stimulating the ingestion of S. typhi by eukaryotic cells are under study at present.
Adhesiveness↗
[Klebsiella pneumoniae adhesion to epithelioid cells in vitro].
The adhesion of K. pneumoniae K24 capsular strain No. 6723 onto subcultured epithelioid human kidney cells RN was studied overtime by light microscopy and by transmission and scanning electron microscopy. To find out the bacterial capsule and glycocalyx of epithelioid cells, the method of staining the samples with ruthenium red was used, this stain producing the coloration of extracellular acidic mucopolusaccharides . The bacteria were found to attach to the qlycocalyx of epithelioid cells by means of protruding areas on the capsule which retained its form and size after both stabilization with ruthenium red and standard glutar -osmium fixation. Under the action of the bacteria epithelioid cells were found to round off, become longer and increase the number of processes. At the sites of contact with the bacteria specific short cytoplasmic processes serving for the attachment of K. pneumoniae cells were discovered.
Adsorption↗
[Electron microscopic study of the interaction of nephritogenic strains of Escherichia coli carrying D-mannose-resistant fimbriae with the cells of a human kidney line].
The electron-microscopic study revealed that nephritogenic E. coli having L-mannose-resistant fimbriae contacted with subcultured human renal cells due to the interaction of fimbriae with microvilli and, less frequently, with the cytoplasmic membrane surrounding the main part of the cell, as well as with the electron-opaque fibrillar material in the intercellular space. The possibility of very close interaction was demonstrated; in some cases this interaction was so close that the outlines of bacterial and epitheloid cells followed each other, the invagination of the external membrane of the host cell being sometimes observed. The expediency of using ruthenium red for detecting fimbriae in morphological studies was shown. The cytopathogenic effect observed in this study and developing by the end of the 5-hour period from the moment of the inoculation of the monolayer with E. coli was manifested by the swelling of mitochondria accompanied by the partial ruptures of cristae, the widening of channels in the endoplasmic reticulum, the appearance of the secondary lysosomes and the increase of their number.
Cell Line↗