Acta microbiologica Academiae Scientiarum Hungaricae最新文献

After an antigenic stimulus in vitro, a fraction was found in the supernatant fluids of spleen (S-1) and thymus (T-1) cell cultures of 70 to 80-day-old sheep fetuses infected with ovine adenovirus in utero. The fraction agreed with alpha-1-fetoprotein in mobility and its molecular weight was 67 000. Injected into adult sheep, S-1 and T-1 had a suppressive effect on the humoral immune response to both adenovirus and Clostridium perfringens D vaccine. Tests with peripheral lymphocytes suggested that fetal cell supernatants do not affect blastogenesis but markedly inhibit Ig synthesis as it could be demonstrated by immunofluorescence tests.

Six different vaccines were prepared, each containing the soluble, practically lipopolysaccharide-free protein extract of 2 or 3 Pseudomonas aeruginosa strains. In active mouse protection tests the vaccines were shown to give protection against both homologous and heterologous serotype strains, and against strain PA-103 producing exotoxin A. In rabbits the vaccines were found to stimulate the production of protective antibodies demonstrable in a passive mouse protection test. The immune serum had a protective effect against the exotoxin A-producing strain PA-103, too. Toxicity of the vaccines was studied in mice (mouse weight gain test) and in rabbits (intracutaneous skin test and pyrogenicity). The vaccines were not or only slightly toxic.

Death occurred earlier and its rate was higher in suckling mice treated with parent or radio-detoxified endotoxin and subsequently inoculated intracerebrally with lymphocytic choriomeningitis (LCM) virus than in their virus infected but untreated control littermates. Thus, in suckling mice both the parent and the radio-detoxified endotoxin pretreatment contributed to the outcome of LCM virus infection in the form of lethal meningitis indicating its increasing effect on the cellular immunological reaction to the virus infection.

Genetic localization of gene(s) coding for erythromycin and oleandomycin resistance in five isolates of phage complex 52, 52A, 80, 81, multiple antibiotic resistant epidemic Staphylococcus aureus was studied. The 100% coelimination rate of erythromycin, oleandomycin, penicillin (penicillinase production) and certain heavy metal ion resistances from each of the clinical isolates and the 100% cotransduction rate of these resistance markers from two clinical isolates as well as changes in the partially purified extrachromosomal DNA patterns of the clinical wild types after elimination and the recipients after transduction indicated that erythromycin and oleandomycin resistance determining gene(s) resided on the penicillinase-heavy metal ion resistance plasmid in each of the isolates. The electrophoretic mobility of these macrolide-penicillinase-heavy metal ion resistance plasmids (MacPc plasmids) was the same in four strains and higher in one strain. These MacPc plasmids did not confer any resistance to spiramycin and lincomycin (even after induction) or to kanamycin, which features differentiate them from MacPc plasmids pI 258 and pTU 512 formerly identified in Staphylococcus aureus in Japan.

Various stable, auxotrophic and nystatin-resistant sterol mutants of Candida albicans were isolated after nitrosoguanidine treatment. Sterol mutants were divided into groups on the basis of the ultraviolet spectra and thin-layer chromatographic patterns of their nonsaponifiable sterol extracts. They were further characterized by their conductometrically measured nystatin-induced ion release. These sterol mutants displayed a decreased growth yield and an increased cell volume. On media containing 0.01% of the carbon sources, most of them could assimilate glycerol, alpha-methyl-D-glucoside, DL-lactic acid, L-sorbose, L-arabinose and ribitol only to a significantly reduced extent, or not at all. It is presumed that these properties result from the altered sterol composition of the plasma membrane.

In the course of urinary tract infections, suckling mice with maternal anti-pilus ("119") immunity showed a massive protection against a 119+ strain of Escherichia coli. Animals could be protected against urinary tract infection by giving pilus antibody or pilus vaccine shortly after the infection. Results showed the importance of adhesive pili in initiating the urinary tract infection by E. coli.

One of the HEp-2 sublines maintained in the authors' laboratory was found to carry LCM virus. The virus proved to be identical with the prototype strain LCM-Am except that its multiplication rate in cell cultures and its mouse pathogenicity were limited. Forty-six cell cultures maintained in 10 Hungarian laboratories were examined for LCM carriership. Sixteen cultures including 11 HEp-2 sublines, all originating from a culture brought into Hungary in 1959, proved to carry the virus. Three FL sublines maintained in two laboratories and two sublines, viz. an RK-13 and a HeLa, maintained in a third one, were also contaminated by LCM virus. In these cases, the carrier HEp-2 subline was the probable source of infection and virus transmission is thought to have occurred in the course of manipulation with cell cultures. The necessity of introducing strict preventive measures in tissue culture laboratories is emphasized in the interest of the laboratory workers and for obtaining reliable laboratory results.

A parvovirus strain was isolated from type 12 human adenovirus. The parvovirus multiplied without helper virus in HEp-2 cell cultures, while its multiplication was enhanced by type 12 and type 18 adenoviruses. Haemagglutinating infective virions as well as soluble haemagglutinins were demonstrated by ultracentrifugation and gel filtration. Virus haemagglutination inhibiting antibodies were found in the sera of healthy rats, whereas sera of healthy persons did not contain antibodies. The parvovirus failed to cause illness in laboratory animals (hamster, mouse, guinea pig).

Human tonsillar lymphocytes bound 14C-labelled homologous IgG, IgA, and IgM at 5 degrees C and released them at 35 degrees C. B cells were found to be more active in this type of Ig binding. The amount of lymphocytes which could be labelled with fluoresceinated anti-human Ig-s decreased during preincubation of the cells at 35 degrees C. Intrinsic Ig-s (determinants of lymphocytes) were demonstrated by immunofluorescent staining preceded by preincubation of the cells at 35 degrees C for 60 min. The ratios of IgG, IgA, and IgM bearing cells in the human tonsillar lymphocyte population were 16.0, 8.0 and 7.4% respectively. The weak binding of Ig-s to the surface of lymphocytes is discussed with regard to the demonstration of surface Ig determinants of lymphocytes.

Nineteen fungi were isolated from different soil samples on the basis of clear zones formed on Rose Bengal Cellulose agar medium. In shake flasks th isolate K1 gave 12.1 units/ml of CMCase activity. A mutant of the isolate K1, KM7, was selected after N-methyl-N'-nitro-N-nitrosoguanidine treatment of the wild-type. This mutant differed morphologically from the parent strain on RBCA medium and gave 36.2 units/ml of CMCase activity which represented about 50% of the enzyme yield from the standard organism, Trichoderma viride QM 9414 (80 units/ml of CMCase activity). The isolate K1, which was identified as a Phoma species, produced 48 units of beta-glucosidase. The yield of beta-glucosidase was increased about 8-fold in the mutant KM7 and was about 68% higher than the level found in T. viride QM 9414.