Acta microbiologica Academiae Scientiarum Hungaricae最新文献

Physicochemical properties and systemic effects of the enterotoxin of Klebsiella pneumoniae has been studied. The enterotoxin had a molecular weight between 10 000 to 50 000. It was protein in nature, and heat and acid stable, inducing a dilatatory response in the gut. It haemolyzed the erythrocytes of various animals including man. It had a capillary permeability activity. In addition, when administered parenterally it increased the level of blood glucose, serum cholesterol, serum alkaline phosphatase and serum acid phosphatase.

Gut samples from 50 nonselected slaughtered chickens were obtained in two poultry processing plants and cultured for Campylobacter jejuni and Salmonella. Positive results were obtained in 84% and 4%, respectively. Viable C. jejuni and Salmonella were detected in every phase of processing, even during packaging for commercial purposes. Of surface samples taken from 118 slaughtered chickens prepared for delivery to consumers, 88 were contaminated by C. jejuni and 17 by Salmonella.

Escherichia coli strains isolated from the alimentary tract of 68 weaned and 44 unweaned pigs with diarrhoea in various parts of Hungary, were tested for the presence of pilus antigens K88, K99 and 987P. K88 was detected in 30% of the strains from newborn pigs and in 12% of the strains isolated from weaned pigs. One strain carried K99. Based on agglutination test and immunoelectron microscopic studies with specific absorbed antisera, five non-haemolytic E. coli strains isolated from newborn pigs were found to produce so-called 987P pili. Three of these strains were designated serologically as O8:K85:H--,987P+ and two as O141: K--:H--,987P+. The Y1 cell assay, the infant mouse assay, and the ligated intestinal loop assay in less than 3-week-old pigs indicated that none of the strains produced heat-labile enterotoxin but all produced a heat-stable enterotoxin detectable in infant mice and in pig loops (STa). All the strains induced diarrhoea in newborn, colostrum deprived pigs and colonized the lower small intestine by adhesion to the villous epithelium. The results have confirmed earlier findings about adhesive virulence attributes caused by 987P pili.

Incorporation of [3H]thymidine ([3H]TdR) into tonsil lymphocytes was inhibited by native Staphylococcus epidermidis while Staphylococcus aureus Cowan I caused stimulation. The inhibitory effect of S. epidermidis was abolished by formalin treatment but not by heat killing. A toxic agent was released from S. epidermidis on gentle water extraction without lysing the bacteria. The extract contained protein and other UV-absorbing material, but did not exhibit haemolytic, lysozyme, catalase or protease activity. The heat-resistant, formalin-sensitive inhibitor present in the aqueous extract of S. epidermidis inhibited [3H]TdR incorporation of lymphocytes in a dose-dependent manner and decreased the viability of lymphocytes.

Methylated bases of the DNA of two mycobacteria (Mycobacterium phlei and Mycobacterium smegmatis var. butyricum) and two mycobacteriophages (Phage phlei and Phage butyricum) have been studied. In both the bacterial and the phage DNAs 5-methyl-cytosine and 6-methyl-aminopurine could be detected. Using L-(methyl-H3)-methionine as methyl donor not only the methylated bases of bacterium and phage DNA proved to be radioactive, but also the non-methylated purine residues and thymine. Possible pathways of this phenomenon are discussed.

Beta-glucuronidase and cathepsin D activity was measured in rabbit sera. A significant increase in beta-glucuronidase activity was found following the intravenous application of a high dose of the parent endotoxin. The enzyme liberating effect of endotoxins irradiated by 50, 100, and 150 kGy was much weaker. Enzyme assays also confirmed that, independent of the irradiation, radiodetoxified endotoxins retain their endotoxin tolerance inducing effect.

The sensitizing activity to egg protein of an A1PO4-adjuvant purified and concentrated influenza-A vaccine was examined in animal experiments and in man. Intravenous injection of ovalbumin caused anaphylactic symptoms and/or fatal anaphylactic shock in prevaccinated guinea-pigs. Ovalbumin-specific antibodies detectable by the passive haemagglutination reaction (PHA) appeared in the blood serum of the vaccinated animals. Model experiments with purified ovalbumin suggested that 1 human dose of the vaccine contained egg protein in the range from 0.1 to 1 ng, and that the antigenic effect of the vaccine grew to more than 10(3)-fold by its adsorption to A1PO4 gel. Adults who in previous years had been immunized with similarly prepared influenza vaccine several times responded with mild reactions; symptoms suggestive of hyperergy did not occur, irrespective of the vaccination history. In the prevaccination serum sample of some vaccines, ovalbumin-specific PHA antibodies were found up to titres independent of the number of the previous immunizations. The concentration of the ovalbumin-specific antibodies of the IgE class was by several orders of magnitude lower in the postvaccination samples than in the serum of some patients hypersensitive to egg protein.

Plasmid elimination in Escherichia coli by a quaternary amine of chlorpromazine was demonstrated on different incompatibility groups of plasmid. The biological effect of the drug depends partly on the host bacteria and partly on the plasmid itself. Various receptor substrates such as adenosine, dopamine, histamine and norepinephrine do not alter the plasmid elimination by promethazine and imipramine. None of the known drug-receptors studied are involved in drug binding of the bacteria. The direct membrane action of imipramine and promethazine was demonstrated in electron microscopic studies and alterations in the bacterial membrane such as discontinuities, phase separation or rarely extensive lytic alterations were observed. Magnesium ions prevent the ultrastructural membrane alterations caused by imipramine and promethazine. There is some evidence that the drugs bind to two different receptor sites simultaneously on the plasmid replication site. The first and strongest binding has to be ionic through the side chain amino group, displacing the bivalent cations. In turn, the two aromatic rings of the fixed (ionically bound) drug molecules bind weakly through pi-electrons, hydrophobically or by a charge transfer complex. This weaker binding together with the ionic one are essential for biologic action and lead to the inhibition of plasmid replication. A schematic model of the effect of tricyclic psychotropic drugs on the bacterial membrane is proposed.

Enzyme-linked immunosorbent assay using ultrasonic lysate of Treponema pallidum and Treponema reiteri as antigens was used for the detection of antisyphilitic antibodies in various stages of syphilis. The conjugate was goat antiserum to human IgG labelled with horseradish peroxidase. A comparison with results of the T. pallidum immobilization test, Rapid Plasma Reagin test, Kolmer complement fixation reaction using cardiolipin and Reiter protein antigens showed that ELISA was more sensitive but less specific with T. pallidum antigen, whereas less sensitive but more specific with T. reiteri antigen. Absorption of group specific treponemal antibodies was needed to make the method reliable.