Acta microbiologica Hungarica最新文献

Aspergillus ochraceus IMI 317911 was screened to be a high cellobiase producing strain (2.40 IU/ml). The mixed batch cultivation of Trichoderma reesei QM 9414/Rut C-30 and A. ochraceus IMI 317911 resulted in a balanced enzyme as compared to singly grown cultures. The milled rice straw (6%, w/v) as carbon source was found suitable for production of cellulases resulting in a Filter Paper Activity (FPA) of 1.83 IU/ml and a cellobiase production of 1.63 IU/ml after 7 days of stirred cultivation. An overall cellulase productivity of 10.89 IU/l/h and an enzyme ratio to cellobiase of 1.12 was achieved.

We investigated the effect of some eucaryotic cytoplasmic structure and function inhibitors on the entry into HeLa cells of the Escherichia coli HB101 K12 strain, harbouring the recombinant plasmid pRI203, in which is cloned a 3.2 Kb chromosomal fragment of Yersinia pseudotuberculosis. Substances impairing microfilament structures and functions (cytochalasin B and trifluoroperazine) significantly reduced invasion ability whereas microtubule organization inhibitors (colchicine and vinblastine) were ineffective. Data obtained with a lipophilic weak base (methylamine), which raises the pH of intracellular vesicles, demonstrated that, in entry pathway of E. coli HB101 (pRI203), endosome acidification is not required. Host cell energy has been shown to contribute to bacterial internalization since the presence of oxidative phosphorylation and glycolysis inhibitors (sodium azide, 2-dinitrophenol and 2-deoxy-D-glucose) during the invasion process, affected bacterial entry.

Six strains of rumen Lactobacillus and four Streptococcus bovis strains isolated from rumen wall and fluid samples were examined for the adherence to cells of primary and secondary cultures of ruminal epithelium (REC) prepared from sheep and calf. S. bovis adhered to the keratinized REC. Ruminal lactobacilli did not adhere. The presence of rumen lactobacilli in mixture had no influence on the adherence of S. bovis strains. No difference was observed in the adherence of tested bacteria to epithelial cells of primary or secondary cultures, but adhesion was only detected on keratinized cells.

Epitope composition of human adenovirus (AV) serotype 13 (subgenus A), 19, 26 and 27 (subgenus D), as well as 41 (subgenus F) was studied with 23 selected monoclonal antibodies (MAbs) raised against different hexon types. With the help of three panels of MAbs great differences were shown in the epitope structure of subgenus D hexons. Comparing two AV13 strain hexons (a prototype strain and an intermediate strain), it was shown that the epitopes recognized by the MAbs were present in different combinations even on strains of the same serotype. Therefore the epitope composition of the subgenus D hexons seems to be heterogeneous.

A modification that simplifies the spot hybridization technique is described for using biotinylated DNA probes. Plasmid EWD299 having LT gene insert, labelled with biotin either by nick translation or using photobiotin was used as DNA probe for the specific detection of enterotoxigenic Escherichia coli. A simple protocol has been described for easy lysis of test samples by boiling in distilled water followed by detergent treatment and was found to be as efficient as the lysis using lysozyme and protease. Three different solid supports namely DEAE-cellulose paper, nitrocellulose paper and nylon membrane were also compared for their suitability in this spot hybridization test. Nitrocellulose paper was found to give better colour signal with the photobiotinylated DNA probe.

Formalinized goose erythrocytes were used in haemagglutination inhibition (HI) and indirect fluorescent-antibody (IFA) tests to detect antibodies to Japanese encephalitis (JE) and West Nile (WN) viruses in equines. Paired serum samples from 31 cases having clinical symptoms of flaviviral infections (JE and WN viruses) and 45 controls were examined. For HI test, formalinized goose erythrocytes were used as such, whereas in IFA test, formalinized goose erythrocytes were first coated with respective viral antigens separately and later used to detect antibodies. By employing HI and IFA tests, paired samples having a titre same or less than two fold rise over the control sera were considered normal for both the viruses. IFA test was found to be a method of choice, due to its sensitivity over HI test.

Phosphatidylcholine (51.2%) and phosphatidyl-ethanolamine (38.3%) are the most abundant phospholipids in the wall-less strain of Neurospora crassa. Insulin treatment exerted no change on the amount of phosphoinositides, although some previous results proved the existence of specific insulin receptors and specific effect of insulin on glucose metabolism in these cells. Long (20 h) treatment with insulin also failed to cause biologically significant changes.

Balb/c (euthymic) and nu/nu (athymic) mice were treated intraperitoneally with TP-4 (a synthetic tetrapeptide, thymopoietin sequence analog) or with Mannozym (1% zymosan suspension), and were infected intracerebrally with LCM virus. Both of the agents contributed to the development of fatal choriomeningitis, consequently stimulated the cellular immune response in euthymic mice, but the athymic mice either treated or not, survived the infection, consequently the agents had no effect on the course of LCM virus infection. Both agents exerted a thymus-dependent cellular immune response stimulating effect. That is, an immunostimulatory effect can be realized only in the presence of the thymus or the T-dependent lymphoid system.

Chloroquine possessing lysosomotrop effects inhibits the development of insulin imprinting both on the plasma membrane and the nuclear envelope. Simultaneously chloroquine can inhibit the insulin binding in the nucleus itself but not in the plasma membrane. There is a dose dependent increase of binding of labelled insulin to the nuclear envelope. The control related binding of nuclei pretreated with insulin or chloroquine is similar and have a direct ratio, independently of the applied concentrations.

Indirect enzyme linked immunosorbent assay (ELISA) was applied for the direct detection of coxsackieviruses in clinical samples viz. rectal swabs (RS) and throat swabs (TS) collected from patients admitted to various nursing homes and local hospitals. Results indicate the presence of different CVA types in 65 (62.5%) out of 104 RS, and 18 (52.9%) out of 34 TS samples. Dot-immunobinding assay was also standardized for the identification of CVA types employing 52 RS samples and the results compared with indirect ELISA. Dot-immunobinding detected more CVA types in a relatively larger number of specimens than indirect ELISA.