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A study on indoor air microbiological contamination in various rooms of university buildings in Poznań, Poland, is presented. Investigations were conducted in the period September-October 2002 and the same period in 2003. Air samples were taken twice a day: in the morning and in the afternoon. In all of the tested places a multiple growth of bacteria and significant increase of mould spores was observed in afternoons. The predominant bacteria and moulds isolated from investigated air samples were: Staphylococcus spp., Micrococcus spp., Serratia spp., Aspergillus spp., Penicillium spp., Rhizopus spp., Cladosporium spp. and Alternaria spp. Among these microbes the presence of pathogenic and strongly allergenic microorganisms was detected.
Microbiological and parasitologic investigations dealing with the influence of aeration on fecal bacteria and Ascaris suum eggs survival in cattle slurry were carried out. The results showed that already the first stage of aeration (reactor I) eliminated quickly a number of Salmonella senftenberg (105 times during 2.5 hours in relation to the control test) and EHEC (108 times during 2.5 hours in relation to the control test) respectively. The longest survival time was for D group streptococci. Inactivation of Ascaris suum eggs due to thermic conditions fluctuated between 50 and 90 minutes. The final stage of aeration (reactor II) completely destroyed pathogen germs and Ascaris suum eggs present in cattle slurry.
The efficacy of five disinfecting agents was tested by a new microbiological method, i.e. the flow cytometry. The method is based on kinetic measurements of the effects of a disinfecting agent on the percent of live/dead cells detected with propidium iodide. E. coli ATCC52922 strain and S. aureus ATCC 29213 strain were used in the experiment. From the measurements the killing time 50 (KT50) was estimated as the period of time needed to kill 50% of microorganisms in the disinfected volume. KT50 for ethanol 70% was lis and it was the most efficient disinfecting agent among all examined. Other commercial preparations were compared with ethanol 70% and were traced throughout the period of 5 min. The results were obtained rapidly, frequently in less than 10 min. In conclusion, the effectiveness of a particular antibacterial disinfectant preparation may be estimated quantitatively within a few minutes by the flow cytometry. The method proved to be very useful for a fast comparison of the effectiveness of various disinfectant preparation against pathological microorganisms.
Slurry often contains many pathogenic microorganisms, which are dangerous to human and animal health. The aim of study was to estimate the elimination rate of indicators and pathogenic bacteria – Escherichia coli, fecal streptococci D-group and Salmonella senftenberg W775 in peat soil according to soil storage temperature and slurry addition. The elimination rate of fecal bacteria was more effective in 20°C than in 4°C. The slowest reduction of the fecal bacteria was observed in soil with slurry. The salmonellas were eliminated more slowly in comparison to another group of investigated microorganisms. The fastest reduction of streptococci was estimated in 20oC, however E.coli in 4°C. To minimize the hazard for environment, slurry should be subjected to monitoring investigation before use on arable land.
In evaluation of food safety, microbiological and physico-chemical requirements are taken into consideration. Food safety assurance is carried out attained by toxicological evaluation of substances present in food, determination of its acceptable (ADI) or tolerable (PTWI or PMTDI) levels for human and adequate legal regulations.
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Human organism, constantly exposed to a large variety of pathogenic microorganisms and their products, such as lipopolysaccharide (LPS), developed innate immunity as a fi rst line of defence. One of the compartments of our organism well equipped with these defence mechanisms is the respiratory system. The cells lining the airways respond to the presence of virulent microorganisms by producing natural antimicrobial peptides, including the only member of the cathelicidins family found to date in humans, peptide LL-37. LL-37 is a small peptide of 37 amino acid residues. The peptide, in addition to its bactericidal effect, plays numerous roles in infl ammatory and tissue remodelling processes. It stimulates angiogenesis, induces proliferation of lung epithelial cells, accelerates wound closure of the airway epithelium, and provokes cytokine release (e.g. IL-8) and cell migration. LL-37 is also able to neutralize LPS, a heteropolymer associated with organic dust, produced by Gram-negative bacteria. LPS (commonly referred to as endotoxin) plays an important role in pathogenesis of many respiratory diseases caused by organic dust, including organic dust toxic syndrome and chronic illnesses such as chronic obstructive pulmonary disease (COPD), asthma or allergic alveolitis (hypersensitivity pneumonitis). LPS is a strong pro-infl ammatory stimulus, inducing in respiratory airways expression of antimicrobial peptides, including LL-37, which is in turn a potent LPS-neutralizing factor. The article discusses the complex interplay between endotoxin and the LPS-neutralizing, pleiotropic peptide LL-37 in pathogenic mechanisms of lung diseases, with regard to closer perspectives of using LL-37 and its derivatives as therapeutic agents.
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