RESUMO
AIMS: Salmonella spp. are an important cause of food-borne infections throughout world, and the availability of rapid and simple detection techniques is critical for the food industry. Salmonella enterica serovars Enteritidis and Typhimurium cause the majority of human gastroenteritis infections, and there are a reported 40,000 cases of salmonellosis in the United States each year. METHODS AND RESULTS: A novel rapid and simple isothermal target and probe amplification (iTPA) assay that rapidly amplifies target DNA (Salmonella invA gene) using a FRET-based signal probe in an isothermal environment was developed for detection Salmonella spp. in pre-enriched food samples. The assay was able to specifically detect all of 10 Salmonella spp. strains without detecting 40 non-Salmonella strains. The detection limit was 4 x 10¹ CFU per assay. The iTPA assay detected at an initial inoculum level of <10 CFU in the pre-enriched food samples (egg yolk, chicken breast and peanut butter). CONCLUSIONS: This detection system requires only a water bath and a fluorometer and has great potential for use as a hand-held device or point-of-care-testing diagnostics. The iTPA assay is sensitive and specific and has potential for rapid screening of Salmonella spp. by food industry.
Assuntos
Proteínas de Bactérias/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Salmonella/isolamento & purificação , Microbiologia de Alimentos/métodos , Genes Bacterianos , Salmonella/classificação , Salmonella/genéticaRESUMO
AIMS: To develop a new rapid real-time polymerase chain reaction (PCR) based detection system for Vibrio parahaemolyticus (V. parahaemolyticus) applicable to raw oyster samples. METHODS AND RESULTS: V. parahaemolyticus cells were artificially inoculated to oysters. Samples were homogenized in 100 ml of sterile saline water and serially diluted to 1.5 CFU ml(-1) level. One millilitre of diluents was centrifuged and the pellet was resuspended with 100 microl of de-ionized water. DNA was extracted by boiling for 20 min, and 0.5 microl was used as a template for PCR reaction. Real-time PCR was performed with TMC-1000 system (1 microl PCR system). The detection system was found to achieve detection limit of 1.5 CFU g(-1) for V. parahaemolyticus. Furthermore, the specificities of these assay systems were confirmed with more than 20 bacterial strains, including various Vibrio species. CONCLUSIONS: Rapid and sensitive food-borne pathogen detection techniques for V. parahaemolyticus is important to the food industry and consumers. The direct detection of V. parahaemolyticus from food is possible with micro real-time PCR system. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that oyster samples can be tested for V. parahaemolyticus with a rapid, specific and simple procedure.
Assuntos
Microbiologia de Alimentos , Ostreidae/microbiologia , Reação em Cadeia da Polimerase/métodos , Vibrio parahaemolyticus/genética , Vibrio parahaemolyticus/isolamento & purificação , Animais , Primers do DNA/genética , DNA Bacteriano/análise , DNA Bacteriano/genética , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Brain astrocytes play a pivotal role in neuronal activities. METHODS: An investigation was undertaken to determine whether juniper oil inhibits heat shock-induced apoptosis of astrocytes. RESULTS: Juniper oil inhibited the heat shock-induced apoptosis in human astrocyte CCF-STTG1 cells. Pretreatment of the cells with juniper oil inhibited the heat shock-induced DNA fragmentation and condensation of nuclear chromatin. Juniper oil alone did not affect the apoptosis. Juniper oil inhibited the heat shock-induced caspase-3 activation and poly-ADP-ribose polymerase (PARP) fragmentation in the human astrocytes. CONCLUSIONS: Juniper oil may inhibit the apoptosis of astrocytes by preventing the caspase-3 activation.
