Acta microbiologica Academiae Scientiarum Hungaricae最新文献

A thin section technique of Ogawa egg yolk culture medium inoculated with Mycobacterium leprae-murium was found to reveal microscopical growth of the strain which could not be demonstrated by macroscopical examination. A peculiar structure of the growth, characterized by many lytic spots different in size, was observed indicating the possible presence of a temperate phage which may interfere with the synthesis of nucleic acids needed for the active multiplication of M. leprae-murium.

Lipopolysaccharide of the Salmonella minnesota Re mutant R595 was irradiated with 60Co gamma doses of 50, 100, 150 and 200 kGy. The irradiated preparations were less toxic, less active in the Shwartzman reaction and as activators of the complement system, but they had retained the protection activity against the lethal action of endotoxin. The irradiation resulted in a dose-dependent decrease in the amounts of constituents (glucosamine, KDO, fatty acids) of the original lipopolysaccharide. With increasing irradiation doses increasing amounts of the irradiated material became dialysable (up to 21% in the 200 kGy sample). Only 50% of total fatty acids were present in the 200 kGy preparation compared to the parent lipopolysaccharide. The degradation products formed during irradiation have not been identified.

Herbicide 2,4-D at a dosage of 500 mg l-1 stimulated the proliferation of the heterotrophic bacterial community present in the water of three fish ponds over a period of one year. 2,4-D due to its toxic action might kill the planktonic algal population occurring in the pond water, which on degradation generated more nutrients conductive to bacterial proliferation. The microbial density in different hours were closely correlated (p less than 0.01 less than 0.05) with the variations of each of NH4-N, NO2-N and specific conductivity of water, while the relationship between the former and PO4-P was reciprocal (P less than 0.001).

The diagnostic value of the leukocyte migration inhibition test was examined by comparing it to other specific laboratory methods i.e. complement fixation, indirect haemagglutination and skin test in 10 patients with acquired lymphoglandular toxoplasmosis. In the acute phase the serological tests gave more reliable results than did the LMI test. In subacute and chronic cases, however, there was a good correlation between dermal reactivity and LMI test. LMI is believed to represent a specific test for the detection of cellular hypersensitivity in human toxoplasmosis and so it can be used as a non-invasive method instead of dermal tests.

Samples were taken from surface waters in Csongrád county in the months March through December, 1980. Escherichia coli isolates selected at random were tested for resistance to 5 antibiotics and for R-plasmid carriership. Of the strains isolated from Tisza river at each of 8 sampling sites, 50-60% were sensitive to all the 5 antibiotics. The percentage of sensitivity was much lower if only the strains isolated during the summer months, when the water level was high, or those isolated from affluents and backwaters were taken into account. The frequency of resistance was the highest for tetracycline, followed in order by ampicillin, streptomycin, kanamycin and chloramphenicol. R-plasmid was carried by 43% of the resistant isolates tested, mainly by multiresistant ones.

Based on the literature and the authors' studies, the genetic markers of Shigella and the chromosome regions connected with pathogenicity are listed. A provisional map of Shigella chromosome and another provisional map indicating the chromosomal regions related to Shigella virulence have been constructed. Both maps could be useful for further genetic investigations of Shigella.

Phages exerting a specific action on Bacillus anthracis were isolated from mitomycin C-induced concentrated lysates of 5 Bacillus cereus strains producing megacin A (phospholipase A). In electron micrographs the phages closely resembled the anthrax-specific, lipid containing phage AP 50 isolated earlier from soil sample. The phages were similar to AP 50 also in their antigenic and chemical structure, host range and sensitivity to organic solvents, detergents and caesium chloride. The DNA character of AP 50 nucleic acid was shown by agarose gel electrophoresis. AP 50 and related phages seem to represent a separate group of phages acting on Bacillus strains.

Intravenous administration of sheep red blood cells resulted in a deficient initial antibody response and provoked a much lower concentration of plaque forming cells in the blood of splenectomized dogs than in the control group. The in vitro serum opsonizing activity on Escherichia coli M-S-15 remained normal after splenectomy, and no difference was found between the test and the control group in the intravascular clearance rate of bacteria injected intravenously.