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I Sh Vaĭsman

Publications and source records attributed to I Sh Vaĭsman.

18 recordsLinked to original sources
PubMed1991

[The immunochemistry of the antigenic fractions of Clostridium tetani toxin].

The localization of tetanospasmin and tetanolysin in C. tetani cells has been determined by the cytochemical method in the dynamics of the development of the microbial population. As shown in this investigation, tetanolysin, similarly to exotoxins, is released from microbial cells into the culture fluid mainly during the first 24 hours of cultivation, while tetanospasmin, similarly to endotoxins, is released only in the process of the destruction of these cells at the phase of the death of the microbial population.

Animals↗
PubMed1986

[Immunocytochemistry of Clostridium novyi antigens. Electron microscopic research].

The dynamics of the synthesis, transfer and excretion of toxin in C. novyi, growing in a liquid culture medium, have been studied on the level of bacterial ultrastructure by means of immunoferritin techniques modified by the authors. As revealed in this study, the basic mechanism of toxin excretion is realized by the active transfer of toxin through the enveloping structures after its accumulation in the periplasmatic space. In ageing cultures toxin may also be released in the process of bacteriolysis with the degradation of bacterial structures.

Antibodies, Bacterial↗
PubMed1985

[Ultrastructural characteristics of the natural heteromorphic growth of Clostridium septicum].

Periodic cultures of C. septicum strain No. 59, growing in Pope's broth, have been studied by means of transmission electron microscopy on ultrathin sections. During the lagphase of growth the inoculated bacilliary cells are sequentially converted into giant filamentous multinucleate forms. These changes, reflecting the reaction of phenotypical adaptation to new environmental conditions, are followed by the restoration of the initial phenotype via the fragmentation of the giant cells. At the same time heteromorphic growth becomes, also spontaneously, atypical in some of the multinucleate cells. This atypical heteromorphic growth results in pronounced degenerative changes leading to bacteriolysis and the death of microbial cells due to disturbances in the coordination of the formation of structural and functional complexes in these cells at the period of their phenotypical adaptation. Such pathology of microbial cells leads to elimination of individual cells with developmental defects, which is finally conducive to the sanitation of the population.

Clostridium↗
PubMed1982

[Fine morphology of the anomalies of sporulation in Clostridium tetani].

The electron microscopic study of the cultures of Cl. tetani strains Nos. 154 and 741 has been carried out, starting from the late stationary phase of their development in a liquid culture medium prepared on the basis of casein hydrolysate. Under experimental conditions sporogenesis is observed in 17-33% of the organisms in the population of strain No. 154 and in 7-14% of the organisms in the population of strain No. 471. In most of the sporulating cells sporogenesis occurs in consecutive stages commonly observed in clostridia. Anomalies in the formation of pores are manifested by the ectopic initial formation of protospores, the disordered excess growth of osmiophil structures of the exosporic type, the early lysis of the cytoplasmic structures of the sporangium cell or the spore itself. Such changes resulting in the death of the cell are regarded as the pathomorphology of the bacterial cell.

Bacteriolysis↗
PubMed1978

[Mechanism of segregation of bacterial chromosomes following division of anaerobic clostridia].

Morphological events during division in Clostridium oedematiens, strains A-277 and A-79, were studied on ultrathin sections. The bacterial cells of the species under investigation containing numerous and various intracytoplasmic membranous structures were practically devoid of the "nuclear mesosomes" type structures. In these anaerobic Clostridia the segregation of bacterial chromosomes after the replication was effected by means of direct connections between the DNA filaments and the cytoplasmic membrane of the bacterial cell. These connections were multiple, up to 250 nm in length, possibly ensuring a proper mechanical strength needed for translocation of the chromosomes into the daughter cells. It is suggested that multiple contact zones between the cytoplasmic membrane and the DNA filaments of the bacterial chromosome arose after the triggering of their DNA replication.

Cell Division↗
PubMed1976

[Enhancement of toxin production and sporogenesis in Cl. tetani 471 cultures under the influence of endogenous metabolites].

A study was made of the dynamics of the population quantity, the delicate morphology of the bacterial cells and the toxin formation in the Cl. tetani 471 cultures grown in fluid nutrient medium with caseine hydrolysate in the industrial 100-litre reactors and under laboratory conditions. Endogenous metabolites contained in the filtrates of the periodic Cl. tetani 471 cultures which reached the phase of accelerated death were capable of enhancement of the toxin formation when introduced in the amount of up to 1 : 100 at the beginning of the exponential growth of the same cultures in the reactors. The growth of the some oligosporogenic strain in the filtrates of the periodic cultures obtained at the beginning of the stationary phase or of the accelerated death phase was characterized by a slower increase in the vegetative cell count, by enhanced spore-formation and by the second, after the initial, increase in the concentration of the microbes partially connected with the spore vegetation.

Clostridium tetani↗
PubMedDate not supplied

[Fine structure of Bifidobacterium bifidum].

Cultures of Bifidobacterium bifidum 1 were grown in liquid and semisolid nutrient media for 14 hours to 6 days. Their preparations were then studied by electron microscopy on ultra-thin sections after a routine chemical fixation or on replicas after rapid freezing-fracturing and etching. This procedure made it possible to obtain new data about the structural organization of cells in the course of growth of cultures which were characterized by desynchronization of growth and division processes. The growth was inhibited later when populations reached the highest number of cells in the given set of conditions. The zone of nuclear vacuoles contained peculiar membrane structures which appeared and underwent certain changes related, apparently, to the mode of growth of this bacterium.

Actinomycetaceae↗