Acta microbiologica Polonica最新文献

The Escherichia coli PrmA enzyme catalyzes methylation of the large ribosomal subunit protein L11. Database homology searches, multiple sequence alignment, and structure prediction allowed to dissect the primary structure of PrmA into two domains and assign putative functional or structural roles to invariant or highly conserved residues. Evolutionary relationships within the PrmA family were also analyzed. The topology of the branching order agrees to a large extent with the consensus phylogeny of Eubacteria, with the exception of beta and epsilon subdivisions of Proteobacteria, which most probably had their original prmA genes replaced by copies acquired via the lateral gene transfer from gamma-Proteobacteria and some close relative of the ancestor of gramnegative bacteria, respectively.

The study involved 196 H. pylori strains and 196 serum samples taken from the same patients. H. pylori strains were investigated for the production of vacuolating cytotoxin. Antibodies to the vacuolating cytotoxin produced by H. pylori were detected in the sera samples by neutralisation assay (on Intestine 407 cells) and ELISA. Of the 196 H. pylori strains tested, 80 (40.8%) were found to express vacuolating cytotoxic activity. The titres of vacuolating cytotoxic were ranged from 1:2 to 1:128. The vacuolating assay was positive in 37.1% strains isolated from children, and in 50% strains isolated from adults. Cytotoxin-positive H. pylori strains were found more frequently in duodenal ulcer (71%) than in chronic gastritis (35.2%) patients, and this difference was statistically significant p<0.05. Neutralising antibodies to vacuolating cytotoxin were present in 51% and 49% of the serum samples tested by neutralisation and ELISA, respectively. Duodenal ulcer patients had antibodies to vacuolating cytotoxin more frequently (p<0.05) than chronic gastritis patients. Antibodies to cytotoxin were detected in 100% of the serum samples from patients infected by cytotoxic H. pylori strains. This suggests that the presence of anticytotoxic antibodies in the serum samples may be regarded as a sensitive indicator of infection by cytotoxic H. pylori strains.

Analysis of the quantitative state of disease causing bacteria and of other microbic groups were done on the sewage sludge from a sewage treatment plant. The results of the analysis include the ammonifying bacteria, nitrifying and denitrifying bacteria. The general quantity of bacteria and fungi in a secondary dehydrated sludge, fermented secondary dehydrated sludge, and in composted secondary dehydrated sludge was deterinated. Composts were prepared from dehydrated secondary sludge with the addition of sawdust. Microbiological analysis of sewage sludge showed, that the quantities of the fecal coli bacteria were 6500; 220 and 150 cells per cm3 of the secondary dehydrated sludge, fermented secondary dehydrated sludge and composted dehydrated secondary sludge, respectively. The numbers of Salmonella were respectively 67.80; 6.48 and 6.60 cells per cm3. The general numbers of bacteria were 2.98 x 10(7); 2.79 x 10(7); 2.15 x 10(7) cells per cm3 of sludge. The cell numbers of fungi were: 6.20x 10(2); 19.60 x 10(2); 7.80 x 10(2) per cm3 of sludge. In the three types of sludge, the results show great numbers of the ammonifying, nitrifying and denitrifying bacteria. Of the analysed groups of bacteria, the highest numbers of cells were found for general bacteria; ammonifying and nitrifying bacteria were next in abundance; still fewer were the denitrifying bacteria. Fungi and pathogenic bacteria were the least numerous.

To carry out efficient insertional mutagenesis in Listeria monocytogenes and to facilitate the characterisation of disrupted genes, a novel derivative of plasmid pACYC 184 was constructed, pLIV virA3, carrying a fragment from the virA region of the of Y. enterocolitica plasmid pYVe 0:9. After transformation of this plasmid into L. monocytogenes it was possible to select for its integration into the host DNA at 42 degrees C. Insertional mutants of L. monocytogenes obtained by using pLIV vector containing plasmid DNA fragments from Y. enterocolitica were constructed and are described.

Recently, significant progress has been made in recognizing virus-aphid specificities and identifying the proteins involved in virus transmission by aphids. An essential role of the viral capsid protein in this process has been proved. Heterologous encapsidation between viruses in mixed infections may allow transmission by aphids of normally non-aphid-transmissible viruses or change virus-vector interactions. This review describes the most characteristic examples of the phenomenon. Recent findings regarding transmission by aphids of viroid encapsidated in the viral capsid protein, and of virus encapsidated in transgenic coat protein, are presented.

Staphylococcus cohnii strains dominated in the environment of investigated hospitals. We isolated 420 strains of the species mainly from hospitals environments, but also from infants--Intensive Care Units patients, its medical staff and non-hospital environments. S. cohnii subspecies cohnii was seen to dominate (361 strains). Seventy seven percent of these strains expressed cell-surface hydrofobicity, most of them were slime producers (61%) and this feature was correlated with their methicillin resistance. Among S. cohnii ssp. cohnii strains isolated from ICU environment 90% were resistant to methicillin, 43% expressed high-level resistance to mupirocin and high percentages were resistant to many other antibiotics. These strains may constitute a dangerous reservoir of resistance genes in a hospital.

The usefulness of four different protocols of permeabilizing human fibroblast cells for detection of CMV immediate-early antigens by flow cytometry was investigated. Permeabilizing protocols employed methanol, methanol/acetone, paraformaldehyde/Triton and FACSPermeabilizing Solution (Becton Dickinson). The best parameters (separation between positive stained CMV infected cells and negative control and detection of infected cells) were achieved for paraformaldehyde/Triton and FACSPermeabilizing Solution (Becton Dickinson).

The aim of the presented research was to settle conditions and parameters of Pleurotus ostreatus (Fr.) Kumm. culture and to determine activity and yield of cellulase complexes biosynthesised by this mushroom on different substrates. Wheat straw sterilized by evaporation at temperature 58-60 degrees C during 48 hours was the first substrate. Wheat straw with Reynoutria japonica (Houtt) in 1:1 proportion, sterilized by irradiation (15 kGy), was the second, two-component, substrate. According to the obtained results it can be ascertained that P. ostreatus (Fr.) Kumm. grows and yields well on all kinds of substrates biosynthesising active cellulase complexes E.C. 3.2.1.4. glucohydrolases, both endo- and exogluconase, and E.C. 3.2.1.21. beta-glucosidase.

The conidia of Aspergillus niger were cultured under various stress conditions. The highest yield of catalase activity was obtained after addition 1.2 M NaCl to 6-h-old culture, which improved the activity of the enzyme by about 2.8-fold in comparison with the control medium without this depressor. A significantly lower increase (1.3- to 1.7-fold) in catalase activity was reached when spores were incubated under oxidative stress (100-200 mM H2O2) or at low pH (2 and 3). Respiratory activities in A. niger culture show important changes with the osmotic stress increase.

Out of 34 studied after-appendectomy tissues of adult and child patients 86 different strains of anaerobes were isolated. The antibiotic susceptibility of 30 isolated B. fragilis strains was tested using E tests. All studied strains were sensitive to imipenem, clindamycin and penicillin/tazobactam. Sensitivity to penicillin and cefoxitin was variable among these strains. One strain resistant to metronidazole (MIC--256 mg/L) and 3 strains with increased MIC to metronidazole were detected. Most of isolated strains were beta-lactamase producers.