Ultrastructural localization of succinate dehydrogenase in some bacteria, after treatment with Lubrol W1.

The localization of succinate dehydrogenase in some gram-negative and gram-positive bacteria (Salmonella typhimurium, Pseudomonas pseudomallei, Pseudomonas aeruginosa and Listeria monocytogenes) treated with the surface membrane active agent, Lubrol W1, was studied by a cytochemical method combined with electron microscopy.

Ultrastructural localization of acid phosphatase in some bacteria, after treatment with Lubrol W1.

The ultracytochemical localization of acid phosphatase from some bacteria (Listeria monocytogenes, Salmonella typhimurium, Pseudomonas pseudomallei and Pseudomonas aeruginosa) was dependent on the changes in the lipoprotein content of the membranes as a result of the action of the Lubrol W1.

Haematoporphyrin and proflavine-sensitized photoinactivation of Salmonella dublin.

The photosensitive activity of haematoporphyrin (HP) and proflavine (PF) on some biological parameters of Salmonella dublin cells was assessed. The investigations showed a decreased respiratory activity of photosensitized PF bacterial cells, accompanied by lower virulence. HP-treatment and light irradiation of salmonellae did not influence their survival in vitro, which was in contrast to the PF-incubated and irradiated cells. Light irradiation of HP- and PF-treated bacteria did not change their phagocytosis from guinea pig alveolar macrophages. In the presence of visible light the PF-treatment considerably reduced the survival rate and multiplication in alveolar macrophages in comparison with HP-treated and light-exposed bacteria. Correlation was established between the degree of structural damage, as observed by electron microscopy and the level of diminution of the chosen biological parameters, which were more strongly expressed after PF-treatment. PF as a photosensitizer which influences the bacterial genomes and its possible practical use, is discussed.

Effect of sorbitan monolaurate polyoxyalkylene (Tween 20) on the ultrastructure of some bacteria.

The ultrastructure of Listeria monocytogenes, Salmonella typhimurium, Pseudomonas pseudomallei and Pseudomonas aeruginosa treated with 0.5 and 1% Tween 20 was studied by means of transmission and scanning electron microscopy. Specific changes in the cell wall and cytoplasmic membrane were observed.

Dark interaction of haematoporphyrin and proflavine with Salmonella dublin cells.

The influence of haematoporphyrin and proflavine on the virulence, survivability, respiratory activity and cell wall ultrastructure of Salmonella dublin cells was studied. There was a decrease in all biological properties investigated, especially when haematoporphyrin was used for dark incubation in comparison with proflavine. The possible clinical use of negatively charged photosensitizers is discussed.

Ultrastructural characteristics of some bacteria after treatment with Lubrol W.

Specific ultrastructural changes occurred mainly in the cell wall and cytoplasmic membrane of Listeria monocytogenes, Salmonella typhimurium, Pseudomonas pseudomallei and Pseudomonas aeruginosa bacteria when treated with 0.5% and 1% Lubrol W1 by means of transmission and scanning electron microscopy.

Ultrastructural changes in some pathogenic bacteria after treatment with ethylendiamintetraacetic acid.

The ultrastructure of Pseudomonas pseudomallei, Pseudomonas aeruginosa. Yersinia pseudotuberculosis, Salmonella typhimurium, Listeria monocytogenes was studied after treatment with EDTA. The study established that the most sensitive species were: Pseudomonas pseudomallei and Pseudomonas aeruginosa. In the case of Listeria monocytogenes changes were not observed. Typical ultrastructural changes in the cell wall and the cytoplasmic membrane were established by means of ultrathin sections, as well as with scanning electron microscopy of Pseudomonas pseudomallei and Pseudomonas aeruginosa.

Ultracytochemical localization of ATP-hydrolysing activity in vegetative cells, spores and isolated cytoplasmic membranes of Bacillus subtilis 168.

The localization of ATP-hydrolysing activity in vegetative cells, spores and isolated membranes of Bacillus subtilis 168 was studied by a cytochemical method combined with electron microscopy. The activity was located mainly in the cytoplasmic membrane and the mesosomes, and was also found in the inner layer of the cell wall facing the cytoplasmic membrane. Activity was also detected in the cross-membranes of dividing cells and in spore coats. The product of the reaction was observed either as fine electron-dense granules incorporated into the membranes, or as high-contrast lead precipitates on the surfaces of the membranes.

Studies on the ultrastructure of Yersinia pseudotuberculosis after treatment with some detergents and solvents.

The ultrastructural changes in 3 strains Yersinia pseudotuberculosis with different virulence after treatment with sodium lauryl sulfate (SLS) and petroleum ether were studied. The ultrafine sections after treatment with SLS show heavy destructive changes, concerning the cell wall, the cytoplasmic membrane and the inner structure of the cell. It was established that the same cells Y. pseudotuberculosis after cultivation on a medium with glycerol show a tendency to recover their ultrastructure. The cells treated with petroleum ether did not exhibit any notable ultrastructural changes.

Persistence and isolation of L cycle forms of Erysipelothrix rhusiopathiae in experimental infection.

In experimental infection of rats induced with teh S-form of Erysipelothrix rhusiopathiae the pathogen was found to persist for a long time (up to fifteen months according to the author's personal observations). Under the effect of the specific and unspecific defense of the animal's organism the causative agent suffered a number of morphologic changes. In the course of the first days of infection the R-form was isolated, and thirty days later up to the fifteenth month forms of the L cycle were recovered from the parenchymal organs, blood, and joints. An electron microscopic study was carried out on the structure of the isolated L-forms. The long-term persistence of the agent in its different morphologic forms may well account for the chronic course of the infection in rats.

Electron microscopic studies on altered forms of Erysipelothrix rhusiopathiae obtained under the effect of novobiocin.

Altered and L-forms of Erysipelothrix rhusiopathiae were obtained through in vitro and in vivo treatments with novobiocin. Electron microscopic studies were carried out on the changes taking place in the morphology and ultrastructure of strains showing a varying degree of resistance. When lower concentrations of the antibiotic were employed (15, 25, 200, 400 mcg) strongly elongated and threadlike forms were established manifesting characteristic changes in the cell wall and the inner structure. The use of high concentrations of novobiocin (1000 and 2000 mcg) incited the production of L-forms the morphology and ultrastructure of which are dealt with in detail.