Microflora of more than 100 samples of different sorts of foodstuff (coarse fodder, grain forage, mixed fodder, premixes, silo, whole milk substitute etc.) selected in 1989-1992 in the period of mass diseases and death of animals in farms of Ukraine has been studied. It is shown that the amount of spore material included in lg of fodder, depends on the sort of feed substrate. Grains and grain forage (94.5 thou. spores in 1 g) occupy the first place in sporification with fungi; vetch-oat mixture and whole milk substitute (82-89 thou. spores)--the second place; mixed fodder granules and maize briquettes (79.5-66.5 thou. spores)--the third place; the latter are mixed fodder plants hay, cereals straw (11.8-43.5 thou. spores). Aspergillus mainly occurred on the concentrated forage, grain, grain forage, in less amount--in grass stand, cereals straw. Penicilli, fusari and other species of saprophytic fungi dominated on hay of natural meadows, on mixed fodder plants and cereals straw. It has been stated that the highest toxicity was typical of the fodder samples infected with Aspergillus strains producing kojic acid. Under conditions of our experiments out of 67 strains of genus Aspergillus kojic acid was synthesized by 48.6% of the total number of the tested fungus cultures. The greatest number of kojic acid producers was found among Aspergillus flavus isolates (56.8%) the less number--among A. fumigatus (36.7%). Kojic acid has been revealed to exert a pathological effect on the organism of different animal species.
While comparatively analyzing the properties of Klebsiella pneumoniae from three studied sources (patients, healthy people, environment), no reliable differences between the comparable strains have been revealed. No differences have been found in the toxin formation, hemagglutinating and antilysozymic activity, adhesivity and invasive properties as well as in the peculiarities of gas exchange, while growing on media with different nitrogen and carbon sources. The studied microorganisms differed only in antibiotic resistance: strains isolated from the environment were sensitive to antibiotics, whereas strains of human origin were resistant to them.
The utilization of the intracellular and extracellular sources of carbon and energy during the mitotic cycle of yeasts Saccharomyces cerevisiae, Kluyveromyces marxianus, Candida boidinii, Candida tropicalis has been studied. Increase in the consumption rate of carbon and energy sources and in the exogenous respiration rate at G1- and G2-phases of the mitotic cycle is shown. The rate of the endogenous respiration of the cells at these phases decreased. The hypothesis has been proposed that during the mitotic cycle of the yeast cell the regular alternation of exotrophy (the utilization of the extracellular carbon and energy sources by a cell) and endotrophy (the process of the utilization of the intracellular carbon and energy sources by a cell) occurs. It is possible to reveal the exotrophic cells by the cytological method which is based on the calculation of dead cells after incubation of the yeast suspension in amyl alcohol solution. This method has revealed that exotrophic and endotrophic processes do not predominate one over another but alternate at the mitotic cycle. Exotrophy and endotrophy are phase-specific processes. The G1- and G2-phases are exotrophic processes, phases S and M are endotrophic ones.
The kinetic and functional characteristics of I and II forms of DNA-dependent DNA-polymerases of Acholeplasma laidlawii PG-8 have been studied. It is stated that I form of DNA polymerase possesses 5'-3'-exonuclease activity and is a typical replicase; II form of DNA-polymerase possesses both 5'-3'-polymerase and 3'-5'-exonuclease activity and is, evidently, a reparase. Both forms of enzyme give preference to poly(U)- and poly(A)-matrices having extremely high activity on these polymers. The enzymatic reactions realized by both forms of DNA-polymerases are described by the first-order equation. The calculated Michaelis-Menten constants equaled 180 and 250 microM for I and II forms of polymerases, respectively. It indicates that affinity to substrate in II form of polymerase is one-third higher than in I form of enzyme.
247 strains of 14 species of bacteria (genus Bacillus) have been studied for the antagonistic properties relative to a wide range of the cattle endometritis agents which are both museum and isolated by authors under the above pathology. Many species of genus Bacillus showed a pronounced antagonism. Active antagonists can occur in different species. Bacillus subtilis strains are the most active. Multiple antibiotic resistance of endometritis agents has no effect on the antagonistic activity of the spore-forming aerobe strains. It is shown that practically the whole range of the possible bacterial endometritis agents is sensitive to the antagonistic effect of the most active strains of aerobic bacilli. The antagonistic strains promising for further studies have been obtained.
Aquatic-phenol trichloroacetic and salt extracts of Pseudomonas aeruginosa have been studied for their effect on hypersensitivity of the delayed type to guinea pig antigen in mice. It is found that salt extracts of wild strains contain thermostable immunosuppressive factors which are of the lipid nature, have high molecular weight and can be inactivated by trichloroacetic acid and phenol. The salt extracts of museum strains as well as aquatic-phenol and trichloroacetic extracts obtained from wild and museum strains had no immunosuppressive activity.
It is shown possible to select the bacterial strains which are neuston ones, i.e., concentrating on the water-atmosphere interface. The preparation based on the neuston form of Bacillus megaterium is more efficient for purification of water polluted with oil hydrocarbons than the preparation based on the planktonic form of the same culture. Preparation based on the neuston form of the aerobic spore-forming bacteria is effective for biological decontamination of sewage treated using conventional methods. Application of neuston bacterial forms permits intensifying the microbiological processes in the thin (15-40 microM) surface layer of water bodies.
Microbiocenosis of skin on hands of 160 men aged 16-60 (of them 40 healthy men not dealing with production (control) and 120 workers of the combine plant) has been studied. The level of bacterial dissemination of persons of the control group has been stated to vary within 3.62 +/- 0.07-3.78 +/- 0.08 1g KOE/lm2. This level in workers of the assembling and metal-working shops essentially decreases and depends on the peculiarities of the production process. The constant contact of skin on hands with oil causes an increase in the amount of bacteria and the contact with emulsions, on the contrary, promotes their decrease. Among the different ecological groups of microorganisms on skin of hands in workers staphylococci occupy a dominating position. The species composition of the latter is nonuniform in workers of different shops. The high level of contamination of skin on hands by Staphylococcus aureus belonging, mainly, to the second phage group has been determined.
The work is a review of the state-of-art of research in the field of biological sensors. The enzymatic and immune biosensors are described. Problems concerning application of microorganisms as biosensors have been reported in detail. The use of luminescent bacteria and luciferase sensors is under discussion. The principles of operation of fibrous-optic and semiconducting biosensors are stated.
Vibrio albensis phages have been found for the first time. Lysogenic strains of the luminescent vibrios are shown to be producers of moderate phages. The vibrios are attributed to the 1st morphological group according to A. S. Tikhonenko's classification. The studied phages are an independent serological type and have no antigenic affinity to cholera phages.
The simple and selective method of anionic biosurfactant concentration determination in bacterial cultural broth is offered. The method is based on the ability of the anionic surfactants to form some coloured complex with the cationic indicator methylene blue registered by spectrophotometer. The suggested method is recommended for the study of biosynthesis of microbial surfactants.
Nonspecific endogenic DNAase has been isolated from biomass of Mycoplasma fermentans PG-18 cells and purified to the homogeneous state. The scheme of isolation consists of purification stages on columns with phosphocellulose, DNA-cepharose CL-8B and phenylcepharose. DNAase was not bound to phosphocellulose, its volume was equal to zero. Then this DNAase was passed through column with DEA-cepharose CL-6B (elution by gradient KCl from 0.1 to 1.8M): enzyme was eluted at KCl concentration in the eluting buffer from 0.1 to 1.2 M. The enzyme was purified to the homogeneous state on column with phenylcepharose (elution by linear gradient of ethylene glycol from 30 to 80%): enzyme was eluted at the concentration of ethylene glycol in the eluting buffer from 43 to 80%. According to data obtained using gel-electrophoresis, under the denaturing conditions molecular mass of enzyme in acrylamide gel was 34 kDa.
The results from comparative studies in the reactions of immunofluorescence, complement binding, diffusion precipitation, hemagglutination, solid-phase immunoenzyme analysis, histochemical variant of immunoenzyme analysis as tests for detection of cattle rotavirus in the process of its isolation from pathological material and adaptation to cell cultures are presented. The immunofluorescence reaction is shown to have an advantage over the other reactions.
The method of electron microscopy has been used to study adhesion of the microbic cells of standard strains of Staphylococcus aureus, Escherichia coli and fungi of genus Candida on the organosilicon sorbent polymethylsiloxane (PMS) and medicamentous complex containing it. This complex contains furazolidone and metronidazole immobilized on silver ions-modified PMS. It is shown that the adhesion of microorganisms is accompanied by their destruction whose rate on pure PMS and medicamentous complex is different. Using experimental data the assumptions are advanced concerning the mechanism of the PMS interaction with Gram-positive and Gram-negative microorganisms as well as with fungi of genus Candida.
