Acta microbiologica Polonica最新文献

The number of parasites increased followed the rapid growing of human population on the Earth. Zoonoses with other medical disorders such allergy accompanied to the parasitic infection are under very carefull investigation. A zoonosis can be transmitted from animals to humans in various ways, depending on life cycle of parasite, the kind of hosts and geographical distribution of species. There are many diseases that can be linked to transmission from not only domestic but also from wild animals (for example Trichinella, Echinococcus, Toxocara, Anisakis). The greater abundance of wild animals may contribute to the wider distribution and increasing prevalence of their parasites (red fox for Echinococcus multilocularis or Trichinella britovi). Zoonotic infections can be transmissed directly from environment when infective stages of parasite contamine water or food. Very important source of zoonoses in humans comes also from foodstuffs of animal origin. Environmental contamination with helminth infective stages needs regular indication for recognition of parasitic species under molecular data and improvement of effective measures to prevent of human zoonotic diseases.

In the following work the influence of air-ions and ozone on the selected microorganisms, first of all on Staphylococcus epidermidis is discussed. Carried out investigations proved that the levels of air-ions concentrations, causing specific changes in the development of particular microorganisms, are very differentiated and depend on individual parameters of those organisms. These levels are generally characterized by high values of concentrations, range n +/- =4 x 10(6) ions/cm3 and are connected with the type of the air-ions used. However investigations did not confirm any negative influence of the positive air-ions seen as a destructive factor upon any of the investigated microorganisms.

Shigella flexneri rods play an important role in human intestinal infections. In the presented studies we have shown that O-acetyl and glucose residues, substituted in main GalNAc-Rha chains of lipopolysaccharide (LPS) are important for the bactericidal effect of human serum. By dot-blot, immunoblotting and ELISA with immobilized LPS we have shown correlation of C3 fragments deposition and serum resistance. LPSs isolated from a serum-sensitive strain deposited more C3 fragments than LPSs from serum-resistant Shigella flexneri strains.

Trans isomers are formed from cis unsaturated fatty acids during biohydrogenation by rumen microorganisms and by commercial partial hydrogenation during the processing of vegetable and fish oils. Recent estimates indicate that consumers in Western countries may receive from 0.5-2.1% to 2.5% of total energy intake as trans fatty acids. In recent years special attention has been given to the potential impairment of essential fatty acids metabolism to their long-chain metabolites by trans isomers in humans. These long-chain polyunsaturates metabolities are of great physiological importance during prenatal and postnatal development, as essential membrane components and precursors for synthesis of prostaglandins and other eicosanoids. Humans do not synthesise trans isomers of fatty acids so their presence in human milk is based on the maternal diet. Trans fatty acids content in human milk varied between countries from 0.35% in Africa to 7.2% of total fatty acids in Canada as a result of variation in dietary exposure to trans isomers. Although the negative effect of the human milk trans fatty acids on breast-fed infants is not yet well documented, ingested levels of trans fatty acids by infants may reflect current breastfeeding mothers diet and also the early consumed diet during pregnancy.

Pure crystals of seven Bacillus thuringiensis field isolates from the Lower Silesia region (Poland) were tested against larvae of Aedes aegypti L. and Culex pipiens L. (Culicidae, Diptera). The crystals of OpQ3 phylloplane isolate (belonging to the first biochemical type of B. thuringiensis subsp. japonensis, yoso, jinghongiensis) killed from 68 +/- 7% to 84 +/- 7% of the fourth instar larvae of A. aegypti. The crystals of two other strains (KpF3 and KpC1) of this group caused mortality between 3 +/- 2% and 70 +/- 7%. The LC50 ranged from 3.2 +/- 0.4 to 34.1 +/- 4.8 microg/ml. The effect of B. thulringiensis wratislaviensis H-47 crystals was the lowest with larval mortality from 0% to 17 +/- 3%. No significant (0%-37 +/- 6%) effect of B. thuringiensis crystals on the larvae of C. pipiens was observed. Our results show that the delta-endotoxins of B. thuringiensis act very specifically.

Many bacterial genomes are under asymmetric mutational pressure which introduces compositional asymmetry into DNA molecule resulting in many biases in coding structure of chromosomes. One of the processes affected by the asymmetry is translocation changing the position of the coding sequence on chromosome in respect to the orientation on the leading and lagging DNA strand. When analysing sets of paralogs in 50 genomes, we found that the number of observed genes which switched their positions on DNA strand is lowest for genomes with the highest DNA asymmetry. However, the number of orthologs which changed DNA strand increases with the phylogenetic distance between the compared genomes. Nevertheless, there is a fraction of coding sequences that stay on the leading strand in all analysed genomes, whereas there are no sequences that stay always on the lagging strand. Since sequences diverge very fast after switching the DNA strand, this bias in mobility of sequences is responsible, in part, for higher divergence rates among some of coding sequences located on the lagging DNA strand.

The environmental route of transmission is important for many protozoan and helminth parasites, with water, soil and food being particularly significant. Both the potential for producing large numbers of transmissive stages and their environmental robustness pose persistent threats to public and veterinary health. The introduction of molecular techniques, in particular those based on the amplification of nucleic acids, has provided researchers with highly sensitive and specific assays for the detection and identification of these pathogens. The application of these techniques to clinical, environmental, and food samples is instrumental for a thorough understanding of the epidemiology of the infection and for the implementation of control measures. Here, the advantages and drawbacks of some molecular techniques (Polymerase Chain Reaction--PCR; Reverse-Transcriptase PCR--RT-PCR; Real-time PCR--qPCR; Nucleic Acid Sequence-Based Amplification--NASBA) will be briefly reviewed. Some application of these techniques will be illustrated with reference to two important and widespread human parasites, the apicomplexan Cryptosporidium and the flagellate Giardia.

More than 72 species of protozoan and helminth parasites can reach humans by food and water, and most of these infections are zoonoses. Some parasites show a cosmopolitan distribution, others a more restricted distribution due to their complex life cycles, which need the presence of one or more intermediate hosts. Of this large number of pathogens, only Toxoplasma gondii can be transmitted to humans by two different ways, i.e., by cysts present in infected meat and by oocysts contaminating food and water. Eleven helminthic species (Taenia saginata, Taenia solium, Taenia asiatica, Trichinella spiralis, Tr. nativa, Tr. britovi, Tr. pseudospiralis, Tr. murrelli, Tr nelsoni, Tr. papuae and Tr. zimbabwensis) can grow in meat of different animal species and can be transmitted to humans by the consumption of raw meat or meat products. Twenty trematode species, four cestode species and seven nematode species can infect humans through the consumption of raw sea- and/or fresh-water food (fishes, molluscs, frogs, tadpoles, camarons, crayfishes). Six species of Cryptosporidium, Isospora belli, Cyclospora cayetanensis, Giardia duodenalis and Entamoeba histolytica/E. dispar can contaminate food and water. Among the helminths, seven trematode species, seven cestode species and five species of nematodes can reach humans by contaminated food and water. Diagnostic and detection methods that can be carried out routinely on food and water samples are available only for few parasites (Cryptosporidium sp., Giardia sp., Anisakidae, Trichinella sp., Taenia sp.), i.e., for parasites which represent a risk to human populations living in industrialised countries. The majority of food and waterborne infections of parasitic origin are related to poverty, low sanitation, and old food habits.

The diagnostic reliability of the IgA immunoblot test in the diagnosis of EBV associated lymphomas was examined. Serum samples from patients with clinically diagnosed lymphomas were tested for the presence of EBV specific IgG and IgA antibodies and based on test results the EBV association with lymphoma was estimated. Obtained results indicated that EBV IgA testing may be helpful in diagnosis of EBV association with lymphomas.

Enrichment, colony isolation and confirmation are three general phases of a standard diagnostic method. E. coli O 157 (the main member of EHEC group) differs metabolically from other strains of E. coli in a number of ways. Most isolates are slow- or non-fermenters of sorbitol and lack the enzyme beta-glucuronidase (GUD). But, a variety of atypical strains of E. coli O157 (sorbitol-fermenting variants, nonmotile and GUD-positive) have been reported. The discovery of these atypical pathogenic strains brings into question the validity of testing for the pathogen only by biotyping. Using classical cultivation and immunomagnetic separation, we have isolated from food a few atypical E. coli O157 (sorbitol-fermenting strains, GUD positive, nonmotile O157 strain which does not agglutinate with O157 latex and does not produce Shiga toxin). On the other hand, non-O157 VTEC (O26 serotype) producing Shiga toxin was isolated from meat. Molecular markers of E. coli O157 and virulence-associated factors of strains with aberrant biochemical properties were studied by PCR. This method helped us in the final identification of isolates. Since it was suggested that the production of verotoxins (VT) is accompanied by the production of enterohemolysin (Ehly) such correlation has also been evaluated in respect to the collection of VTEC of human, animal and food origin.