[cis and trans conformational changes of bacterial fatty acids in comparison with analogs of animal and vegetable origin].

The conditions of the formations of trans isomers of fatty acids, depending on the method of processing and storage of the raw material of microbial, plant and animal origin, were investigated. In the composition of lipids, except for the main trans-isomer elaidic acid, nonsignificant amounts of trans-2-hexen-4-ynal, trans-2-formlcyclopro-panecarboxylate, methyl octadeca-9-yn-l1-trans-enoate, trans-2, 2-dimethyl-3-(2-propenyl)-ethyl ester, trans-9-octadecenoic acid, and trans-1,5-heptadiene, and mixed isomers of methyl-octadeca-9-yn-1-trans-enoate, methyl-9-cis, 11-trans-octadecadienoate, 1-[trans-4-(2-iodo-ethyl) cyclohexyl]-trans-4-pentylcyclo-hexane and cis-9, and trans 11-octadecenoic acid. The major trans elaidic acid component was detected in natural objects of different origin in quantities not exceeding 0.05-0.11%. The combination of thermal processing with other parameters, especially enzymatic treatment, led to an increased proportion of trans isomers. The content of trans isomers is usually proportional to the time of storage of materials.

[The electron microscopic study of bacterial development in colonies. The heteromorphous growth of bacteria during the natural development of a population]. / Elektronno-mikroskopicheskoe issledovanie razvitiia bakterii v koloniiakh. Geteromorfnyi rost bakterii v protsesse estestvennogo razvitiia populiatsii.

In this work data on the morphological features of the heteromorphous growth of bacteria in the process of the natural development of their population are presented. The authors believe that the heteromorphous growth of cells is inherent in the normal cycle of the development of bacteria in the population and that this process is reversible. It has certain regularities, common for different bacteria, in the variability of morphological manifestations and can be regarded as one of the stages of the natural L-transformation of bacteria.

[Electron microscopic study of bacterial development in colonies. The morphology of bacterial colonies]. / Elektronno-mikroskopicheskoe issledovanie razvitiia bakterii v koloniiakh. Morfologiia kolonii bakterii.

The morphology of colonies of some pathogenic Gram-negative and Gram-positive bacteria has been studied by scanning and transmitted electron microscopy. The presence of covers on the surface of cells in colonies has been revealed. The examination of colony fragments in ultrathin section has revealed that cells exist in associations and the elements of cell covers are differentiated in the form of fibrillar structures in the intracellular space. This investigation has shown that covers in the colonies of the bacteria under study should be regarded as their morphological feature playing an important role in the development of the infectious process.

[Structural changes in spores under high temperature exposure]. / Strukturnye izmeneniia spor pri vozdeistvii vysokoi temperatury.

The electron microscopy of ultrathin sections of B. cereus spores showed that no lysis and destructive changes occurred in the main structural components of the spores when heated to 99 degrees C (in distilled water). By the time 99% of the population were destroyed, the spores seemed to preserve the exosporium of the sporoderm, the cortex and the sporoblast intact. Even autoclaving at 120 degrees C for 15 min brought about no visible changes in the ultrastructure of the spores, though it killed the whole spore population.

[Submicroscopic study of bacteria and spores under the effect of peracetic acid and various aspects of the mechanism of its action]. / Submikroskopicheskoe izuchenie bakterii i spor pri vozdeistvii naduksusnoi kisloty i nekotorye aspekty mekhanizma deistviia preparata.

Microbial cells (E. coli and staphylococcus) and B. cereus spores were used in this work. Peracetic acid in a concentration of 0.005% caused the death of 99% of the microbes in 20 minutes, and 0.1% peracetic acid caused the death of 99% of the spores in 45 minutes. Changes in the surface and internal structures of the cells were revealed on the ultrathin sections of microbial cells and spores after the action of the preparation. The noted changes were explained by disturbance of permeability barrier and a high reactogenic capacity of the activated oxygen of peracetic acid.

[Relationship between the ultrastructure and biochemical composition of spores and their resistance to high temperature exposure and chemical agents]. / Ustoichivost' spor k vozdeistviiu vysokoi temperatury i khimicheskikh sredstv v zavisimosti ot ikh ul'trastruktury i biokhimicheskogo sostava

The author used the spores of B. cereus and of its two mutants (10id -- defective by spore coats, and No. 3 -- DPA-deficient). The mentioned microbes were subjected to the action of vapour (99 degrees), 5% sodium hydroxide solution at a temperature of 50 degreeC, and of 0.25% sodium hypochlorite solution. On the basis of the survival curves it was revealed that a mutant with defective coats possessed the least resistance to the factors under study. On these grounds a conclusion was drawn on the important portective function of the spore coat, and not simply of the presence of DPA, in the mechanism of thermo- and chemical resistance of spores.

[Structural and biochemical changes in the spores of Bacillus cereus exposed to caustic soda and hypochlorite]. / Strukturnye i biokhimicheskie izmeneniia spor Bacillus cereus pri vozdeistvii edkogo natra i gipokhlorita

The spores of Bacillus cereus were treated with 5% NaOH at 50 degrees C and 0.25% NaOCl. As a result, 99% of the spores had lost their viability by the 11th and 19.5th minutes, respectively. Kinetics of the process has shown that the rates of elimination of calcium and dipicolinic acid from the spores are different, and intensive loss of RNA and DNA was registered. Progressive degradation of spore envelopes and inner structures has been revealed by electron microscopy. Lethal effect of the studied chemical substances is presumed to be related to changes in the spore envelopes, thus interfering with normal barriers of permeability.