[Detection of coronavirus in experimental pneumocystic pneumonia].

Transmission electron microscopy (of ultrathin sections) was used to examine the biomass of lung tissue in the immunodeficiency minipigs experimentally infected with Pneumocystis carinii. The material was found to contain pneumocysts, bacteria, and coronaviruses. There was a clear coronavirus-pneumocyst structural relationship. The findings suggest the combined effect of microorganisms of different systematic groups on the development of a pathological process in the experimental infection etiologically determined by Pneumocystis carinii.

Ultrastructural study of chitosan effects on Klebsiella and staphylococci.

Antibacterial effect of chitosan on the morphofunctional organization of clinical strains of Klebsiella pneumoniae and Staphylococcus aureus was studied by transmission electron microscopy. Chitosan promoted aggregation of bacterial cells and disorganization of bacterial cell wall and cytoplasmic membrane, which leads to the release of bacterial contents into the environment. These structural changes result in bacterial death.

[Ultrastructure of Yersinia pseudotuberculosis in the process of their reversible transition into the dormant (non-culturable) state in association with blue-green algae]. / Ul'trastruktura Yersinia pseudotuberculosis v protsesse obratimogo perekhoda v pokoiashcheesia (nekul'tiviruemoe) sostoianie v assotsiatsii s sine-zelenymi vodorosliami.

The ultrastructural organization of Y. pseudotuberculosis in the process of the transition of vegetative cells into the dormant (noncultivable) state in interaction with blue-green algae of the species Anabaena variabilis was studied by the method of transmission electron microscopy. The use of type specific Y. pseudotuberculosis serum made it possible to identify Y. pseudotuberculosis cells in the bacterial association and to find out whether their antigenic properties remained intact in time. The dormant forms of Y. pseudotuberculosis, recultivated by passage through the axenic culture of unfusoria (Tetrahymena pyryformis), were also studied with the use of electron microscopy. The revertants were found to be at different stages of restoration of their typical morphological characteristics and antigenic properties were partially retained. The fine structure of Y. pseudotuberculosis cells in the initial culture was shown to be similar to that of the revertants of dormant forms, morphological criteria of the dormant cell ultrastructure were established. The cyclic processes of reversible transition from vegetative forms to dormant ones in bacterial populations under the influence of hydrobios is regarded as an adaptive mechanism of their existence in the environment.

Ultrastructural organization of Helicobacter pylori under natural conditions and during ex vivo culturing.

Ultrastructure of Helicobacter pylori were studied by transmission electron microscopy in freshly isolated and ex vivo cultured biopsy specimens of gastric antral mucosa from patients with duodenal ulcer.

[Ultrastructural organization of Salmonella typhimurium cells during long-term starvation and transfer to an unculturable state]. / Ul'trastrukturnaia organizatsiia kletok Salmonella typhimurium pri dlitel'nom golodanii i perekhode v nekul'tiviruemoe sostoianie.

Electron microscopic and immunocytochemical studies of Salmonella typhimurium culture were carried out under conditions of cell transfer into an unculturable state induced by carbon, phosphorus, and nitrogen starvation. Morphological variants of bacterial cells were detected in the course of cell culturing under conditions of starvation. Electron microscopy showed that O-antigen was retained in salmonella after long starvation and transfer into an unculturable state.

[The ultrastructural characteristics of Francisella tularensis interaction with Tetrahymena pyriformis]. / Ul'trastrukturnye osobennosti vzaimodeistviia Francisella tularensis s Tetrahymena pyriformis.

The electron-microscopic study of the interaction of F. tularensis virulent and attenuated strains with infusoria of the species T. pyriformis was dynamically studied. In this study the structural changes of F. tularensis and T. pyriformis cells, as well as their capacity for survival, were revealed. The data on their ultrastructure correlated with the dynamics of the number of both F. tularensis and T. pyriformis: during the whole term of observation the tendency to a slow decrease in the number of F. tularensis was registered with the concentration of T. pyriformis remaining stable. The interaction of F. tularensis with T. pyriformis may be regarded as a variant of commensal, but not antagonistic interactions.

[Dormant forms of Yersinia pseudotuberculosis during interaction with green algae and their exometabolites (population dynamics and ultrastructure)]. / Pokoiashchiesia formy Yersinia pseudotuberculosis pri vzaimodeistvii s zelenymi vodorosliami i ikh ékzometabolitami (populiatsionnaia dinamika i ul'trastruktura).

The dynamics of the transition of Y.pseudotuberculosis to the latent (noncultivable) state in sterile soil extraction and in soil extraction, containing Scenedesmus algae or their exometabolites, was evaluated by the bacteriological method and with the use of polymerase chain reaction. The formation of Y.pseudotuberculosis latent forms achieved its highest rate under the action of algal exometabolites (on day 11), while in the presence of algal cells such formation was delayed to 3-5 months. The partial reversion of Y.pseudotuberculosis nonculativable forms to vegetative, bacteriologically detectable forms occurred under the action of fetal serum, as well as live or killed infusoria. Transmission electron microscopy demonstrated that noncultivable Y.pseudotuberculosis had a round form, diminished cell size, denser cytoplasm and enlarged cytoplasmic space. The reversible transition of bacteria to the latent state is regarded as their adaptation to unfavorable factors during their existence in soils and water reservoirs.

[Ultrastructural and immunocytochemical study of Listeria monocytogenes with varying levels of pathogenicity factor production]. / Ul'trastrukturnoe i immunotsitokhimicheskoe izuchenie Listeria monocytogenes s razlichnym urovnem produktsii faktorov patogennosti.

Wild and mutant strains of Listeria monocytogenes are examined by electron and immunoelectron microscopy. The mutant strain was characterized as a strain with a high level of production of pathogenic factors. No essential morphological criteria permitting the differentiation between wild and mutant Listeria strains were detected. Addition of activated charcoal to nutrient medium resulted in similar morphological changes in both strains. Enlargement of cells, a thicker cell wall, and changes in the cytoplasm structure are objective morphological signs of functional activity of bacteria with a higher level of pathogenic factor production. Indirect immunocytochemical method demonstrated the localization of specific phosphatidyl inosityl phospholipase C.

[A novel method of concentrating bacterial suspensions for transmission electron microscopy]. / Novyi metod kontsentrirovaniia bakterial'nykh suspenzii dlia transmissionnogo élektronno-mikroskopicheskogo analiza.

Presents a new method for making preparations of bacteria and their unculturable forms from suspensions with low concentrations of cells, from 1 x 108 to 1 x 104 per ml. to be examined under transmission electron microscope. The novelty of the method consists in the technique of concentrating bacteria by making a colloid solution consisting of bovine serum albumin and polyethyleneglycol. Associations of protein molecules, polyethyleneglycol, and bacteria, forming in the solution, are sedimented by centrifugation after 48-hour incubation at 4 degrees C. The solidity of the resultant macroscopic sediment is sufficient for studying the cells contained in it under transmission electron microscope.

[The characteristics of new species of pathogenic microorganisms in the genus Francisella]. / Kharakteristika novykh vidov patogennykh mikroorganizmov roda Francisella.

The comparative study of newly discovered pathogenic bacteria of the genus Francisella was carried out with the use of a complex of microbiological and serological methods. While having great similarity to the causative agent of tularemia, F. novicida, F. novicida-like bacteria and F. philomiragia had lesser growth requirements, some specific morphological and structural features, were capable of fermenting sucrose and exhibited low pathogenicity to experimental animals. The strains under study proved to be virulent with regard to golden hamsters, who were for this reason proposed as an adequate model for the isolation of these bacteria from environmental objects and pathological material obtained from patients. The use of immunoblotting made it possible to find out that all Francisella species had protein antigens, similar to their electrophoretic mobility and serological activity.

Ultrastructure of circulating immune complexes isolated from the blood plasma of patients suffering from infectious diseases.

An original procedure which permits to isolate circulating immune complexes (CIC) from the blood plasma in a form of a dense pellet was developed. This procedure was applied for the ultrastructural analysis of CIC isolated from blood of healthy blood donors and patients suffering from Yersinia enterocolitica (YE) and Yersinia pseudotuberculosis (YP) infections. The here reported method of CIC isolation from blood plasma permitted to visualize CIC electronmicroscopically as amorphous masses of low, middle, and high electron density with inclusions of cell debris. In contrast to CIC of healthy blood donors, CIC of infected patients contained various bacteria and fungiformic structures. For the first time, this method made possible an ultrastructural demonstration of bacterial destruction outside of phagocytes in vivo. This method also permits to visualize and identify bacteria in cases of lingering forms of infection when hemoculture tests fail. Therefore, electronmicroscopic examination of CIC preparations from the blood plasma might be a very informative indicator of bacteriemia in the course of an infection process and serve as an indicator of therapeutic effects. In lingering forms of an infection process, ultrastructural analysis of CIC preparations can be of prognostic value and serve as an indicator of therapeutic effects. This method might be also advantageous as an additional test for the exposure of latent bacterial persistence in diagnostically complicated cases.

[Pseudomonads as parasites of protozoa]. / Psevdomonady kak parazity prosteishikh.

The experimental study of the interaction of Tetrahymena pyriformis with different microorganisms of the genus Pseudomonas, isolated from the soil, was made. The study revealed that T. pyriformis phagocytosed some Pseudomonas pigment-forming species (P. cepacia, P. putida, P. fluorescens, P. pirkettii). The most pronounced cytopathogenic effect was produced by P. cepacia. The dynamic observations of the ultrastructural features of interaction between P. cepacia and protozoa were made. Even at early stages of this interaction some types of parasitiferous phagosomes containing both intact bacteria capable of multiplication by binary division and Pseudomonas cells exhibiting different degrees of destruction were registered. In several phagosomes morphologically intact bacteria differing in their cell-wall profiles and the density of their cytoplasm and nucleotide were present simultaneously. More dense cells with sinuous cell-wall membranes were more virulent. By hour 18 one giant parasitiferous vacuole was formed by fusion of smaller phagosomes, which subsequently broke up, liberating a new generation of bacteria. In infected cells disturbances in the structure of their mitochondria and macronucleus appeared. During the first 2 days of the joint cultivation of P. cepacia and T. pyriformis the accumulation of bacteria occurred due to the selection and multiplication of digestion-resistant bacterial cells, which ensured the resistance of this Pseudomonas population in association with protozoa.

[The ultrastructural characteristics of the interaction of Legionella pneumophila with the infusorian protozoon Tetrahymena pyriformis]. / Ul'trastrukturnye osobennosti vzaimodeistviia Legionella pneumophila s prosteishimi--infuzoriiami Tetrahymena pyriformis.

In this work the morphological features of the interaction of L. pneumophila virulent strain and T. pyriformis have been studied on the submicroscopic level in the time course of the process. The study has shown the process of the destruction of the bacterial population and the penetration of individual intact Legionella cells from the phagosome into the endoplasm of T. pyriformis after 6-9 hours of interaction in the form of the budding of the phagosome and further multiplication of Legionella in the endoplasm. As revealed in this study, T. pyriformis have two types of phagosomes characterized by different variants of the destruction of Legionella. In T. pyriformis lysosomes-like granules, mitochondria and the granular endoplasmatic network take part in the process of interaction. The process of interaction has been found to end by day 7 in the death of all protozoal cells taking part in interaction.

[The combined action of microwave radiation and hydrogen peroxide on the viability and ultrastructure of Pseudomonas aeruginosa cells]. / Sochetannoe deistvie mikrovolnovogo izlucheniia i perekisi vodoroda na zhiznesposobnost' i ul'trastruktury kletok Pseudomonas aeruginosa.

The comparative study of the action of microwave radiation and hydrogen peroxide, as well as their combined action, on the viability and ultrastructure of P. aeruginosa cells has been made. The combined use of microwave radiation and hydrogen peroxide has been shown to decrease the viability of P. aeruginosa 1.5-2 times in comparison with the isolated action of each factor. The electron microscopic study of the ultrastructure of cells have shown the deterioration of the surface structures, nuclear and ribosomal apparatus of the cells under the isolated action of each of the above-mentioned factors or under their combined action. The morphological picture of these changes has proved to be different. The maximum changes in the ultrastructure of P. aeruginosa cells have been registered after the combined action of these bactericidal factors.

[An analysis of the mechanisms of interpopulation interaction of Yersinia with Tetrahymena pyriformis infusorians at the cellular and subcellular levels]. / Analiz mekhanizmov mezhpopuliatsionnogo vzaimodeistviia iersinii s infuzoriiami Tetrahymena pyriformis na kletochnom i subkletochnom urovniakh.

The mechanisms of interaction between the populations of Yersinia and T. pyriformis have been analyzed on the cellular and subcellular levels. As shown in this investigation, Yersinia, when phagocytized by T. pyriformis, may undergo morphological changes, remain unchanged and also multiply, destroying the host cell in the process.

[Outer membranes of Francisella tularensis and their protein composition]. / Naruzhnye membrany tuliaremiinogo mikroba i ikh belkovyi sostav.

Four strains of the species Francisella tularensis were used in the present work: a live vaccine strain 15/10 and three virulent strains (503, Schu, 543) from three different subspecies. The bacterial membranes were prepared by the 0.5% N-laurylsarcosinate (Sarcosyl) treatment. These membranes were identified as the outer membranes by morphological, immunological and biochemical analyses. The outer membrane proteins contained up to 30-35 polypeptides with three dominant fractions having the 63, 48 and 41-43 kD molecular masses. Despite the significant similarity between the membranes protein profiles there were some quantitative and qualitative differences between the three variants of Francisella tularensis in polypeptides compositions and patterns.

[Dissociation and ultrastructure of the cells of Shigella sonnei isolated from gnotobiotes and obtained in vitro]. / Dissotsiatsiia i ul'trastruktura kletok Shigella sonnei, vydelennykh ot gnotobiontov i poluchennykh in vitro.

The dissociation variants of S. sonnei in phase I, isolated from germ-free rats and obtained in vitro, have been studied. Such dissociation variants have been found to form colonies with classical and atypical morphology. The electronmicroscopic study has revealed that different dissociation variants include small dense cells with the markedly thickened cell wall and pronounced microcapsule and spheroplasts with the damaged cell wall and less pronounced microcapsule. The formation of these cells is supposed to be the way of the adaptation of S. sonnei in the course of the infectious process and linked with changes in their virulence in the population cycle.

[Isolation and ultrastructure of Yersinia spheroplasts and protoplasts]. / Poluchenie i ul'trastruktura sferoplastov i protoplastov u iersinii.

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.

[Staphylococcal dehydrogenase activity after application of the antibacterial preparation baliz-2. A biochemical and electron microscopic study]. / Degidrogenaznaia aktivnost' u stafilokokka posle deistviia antibakterial'nogo preparata baliz-2. Biokhimicheskoe i élektronno-mikroskopicheskoe izuchenie.

The study carried out by means of biochemical and electron-microscopic techniques has shown that the antibacterial preparation baliz-2 at low and therapeutic concentrations suppresses the dehydrogenase activity of staphylococcal cells and their membrane fraction.