Salmonella spp. surface transfer patterns/models between ready-to-eat (RTE) deli meat and a typical meat slicer are presented. A five-strain cocktail of Salmonella spp. was inoculated directly onto the rim of a round ...Salmonella spp. surface transfer patterns/models between ready-to-eat (RTE) deli meat and a typical meat slicer are presented. A five-strain cocktail of Salmonella spp. was inoculated directly onto the rim of a round slicer blade at an initial level of ca. 4, 5, 6, 7 or 8 log CFU/blade (ca. 3, 4, 5, 6 or 7 log CFU/cm2 of the blade edge area). Thereafter, a RTE deli meat (ham) was sliced to a thickness of 1.5 - 2.0 mm. In another cross-contamination scenario, a clean blade was initially used to slice ham, which was pre-surface-inoculated with the Salmonella cocktail (ca. 2, 3, 4, 5, 6 or 7 log CFU/cm2 with a total area of 100 cm2), followed by slicing of an un-inoculated ham. The log CFU of Salmonella per ham slice was determined and empirical models were developed. The models, follow the decreasing Power law, predict the surface cross-contamination of Salmonella spp. (at any initial level) for sliced deli meat (ham) and will provide a useful tool in developing RTE meat risk assessments. Surface transfer patterns of three foodborne pathogens, i.e. Listeria monocytogenes, E. coli O157:H7 and Salmonella predicted by models are also presented.展开更多
Background:Bacillus cereus is an important pathogen that causes human food poisoning,specifically diarrhea and vomiting.B.cereus can also induce mastitis in dairy cows and has a strong survival ability in milk,as it c...Background:Bacillus cereus is an important pathogen that causes human food poisoning,specifically diarrhea and vomiting.B.cereus can also induce mastitis in dairy cows and has a strong survival ability in milk,as it cannot be inactivated by high-temperature short-time pasteurization.Therefore,B.cereus can enter the market through pasteurized milk and other dairy products,imposing enormous hidden dangers on food safety and human health.Results:In this study,B.cereus 2101(BC)was isolated from milk samples of cows with mastitis.BC grew rapidly with strong hemolysis,making it difficult to prevent mastitis and ensure food security.MAC-T cells were treated with BC and/or Lactobacillus rhamnosus GR-1(LGR-1).Pretreatment with LGR-1 protected the integrity of tight junctions and the expression of zonula occludens-1(ZO-1)and occludin destroyed by BC.Furthermore,LGR-1 pretreatment reduced the expression of NOD-like receptor family member pyrin domain-containing protein 3(NLRP3),caspase recruitment and activation domain(ASC),Caspase-1 p20,gasdermin D(GSDMD)p30,inflammatory factors(interleukin(IL)-1βand IL-18),and cell death induced by BC.Moreover,LGR-1 pretreatment reduced NLRP3 inflammasome activity and increased expressions of ZO-1 and occludin induced by lipopolysaccharides(LPS)+ATP stimulation.MAC-T cells were transfected with NLRP3 si RNA or MCC950 and/or treated with BC and/or LGR-1.NLRP3-si RNA transfection and MCC950 attenuated BC-induced NLRP3 inflammasome activity.Expression of inflammatory cytokines and cell death suggested that the inflammatory pathway might play an important role in the induction of the NLRP3 inflammasome by BC and the protection of LGR-1.Conclusions:These results suggest that LGR-1 might be a probiotic alternative to antibiotics and could be administered to prevent mastitis in dairy cows,thus ensuring food security.展开更多
Rapid and accurate laboratory diagnosis of SARS-CoV-2 infection is crucial for the management of COVID-19 patients and control of the spread of the virus. At the start of the COVID-19 pandemic, Bangladesh had only one...Rapid and accurate laboratory diagnosis of SARS-CoV-2 infection is crucial for the management of COVID-19 patients and control of the spread of the virus. At the start of the COVID-19 pandemic, Bangladesh had only one government molecular laboratory where real-time RT-PCR would be performed to diagnose SARS-CoV-2 infection. With the increasing number of suspected cases requiring confirmation diagnostic testing, there is a requirement to expand capacity for large-scale testing quickly. The government of Bangladesh established over 100 molecular laboratories within one year to test COVID-19. To expand the testing capacity, the government was compelled to recruit laboratory staff with limited experience and technical expertise, especially in molecular assays, to process specimens, interpret results, troubleshoot. As a result, the risk of diagnostic errors, such as cross-contamination, increased, potentially undermining the efficacy of public health policies, public health response, surveillance programs, and restrictive measures aimed toward containing the outbreak. In this piece, we discuss the different sources of cross-contamination in the COVID-19 RT-PCR laboratories and proffer practical preventive measures to avoid them.展开更多
Cells are highly sensitive to their geometrical and mechanical microenvironment that directly regulate cell shape,cytoskeleton and organelle,as well as the nucleus morphology and genetic expression.The emerging two-di...Cells are highly sensitive to their geometrical and mechanical microenvironment that directly regulate cell shape,cytoskeleton and organelle,as well as the nucleus morphology and genetic expression.The emerging two-dimensional micropatterning techniques offer powerful tools to construct controllable and well-organized microenvironment for single-cell level investigations with qualitative analysis,cellular standardization,and in vivo environment mimicking.Here,we provide an overview of the basic principle and characteristics of the two most widely-used micropatterning techniques,including photolithographic micropatterning and soft lithography micropatterning.Moreover,we summarize the application of micropatterning technique in controlling cytoskeleton,cell migration,nucleus and gene expression,as well as intercellular communication.展开更多
文摘Salmonella spp. surface transfer patterns/models between ready-to-eat (RTE) deli meat and a typical meat slicer are presented. A five-strain cocktail of Salmonella spp. was inoculated directly onto the rim of a round slicer blade at an initial level of ca. 4, 5, 6, 7 or 8 log CFU/blade (ca. 3, 4, 5, 6 or 7 log CFU/cm2 of the blade edge area). Thereafter, a RTE deli meat (ham) was sliced to a thickness of 1.5 - 2.0 mm. In another cross-contamination scenario, a clean blade was initially used to slice ham, which was pre-surface-inoculated with the Salmonella cocktail (ca. 2, 3, 4, 5, 6 or 7 log CFU/cm2 with a total area of 100 cm2), followed by slicing of an un-inoculated ham. The log CFU of Salmonella per ham slice was determined and empirical models were developed. The models, follow the decreasing Power law, predict the surface cross-contamination of Salmonella spp. (at any initial level) for sliced deli meat (ham) and will provide a useful tool in developing RTE meat risk assessments. Surface transfer patterns of three foodborne pathogens, i.e. Listeria monocytogenes, E. coli O157:H7 and Salmonella predicted by models are also presented.
基金the following funds:the National Key R&D Program of China(Project No.2017YFD0502200)the National Natural Science Foundation of China(Project No.31960721)the National Natural Science Foundation of China(Project No.31873034)。
文摘Background:Bacillus cereus is an important pathogen that causes human food poisoning,specifically diarrhea and vomiting.B.cereus can also induce mastitis in dairy cows and has a strong survival ability in milk,as it cannot be inactivated by high-temperature short-time pasteurization.Therefore,B.cereus can enter the market through pasteurized milk and other dairy products,imposing enormous hidden dangers on food safety and human health.Results:In this study,B.cereus 2101(BC)was isolated from milk samples of cows with mastitis.BC grew rapidly with strong hemolysis,making it difficult to prevent mastitis and ensure food security.MAC-T cells were treated with BC and/or Lactobacillus rhamnosus GR-1(LGR-1).Pretreatment with LGR-1 protected the integrity of tight junctions and the expression of zonula occludens-1(ZO-1)and occludin destroyed by BC.Furthermore,LGR-1 pretreatment reduced the expression of NOD-like receptor family member pyrin domain-containing protein 3(NLRP3),caspase recruitment and activation domain(ASC),Caspase-1 p20,gasdermin D(GSDMD)p30,inflammatory factors(interleukin(IL)-1βand IL-18),and cell death induced by BC.Moreover,LGR-1 pretreatment reduced NLRP3 inflammasome activity and increased expressions of ZO-1 and occludin induced by lipopolysaccharides(LPS)+ATP stimulation.MAC-T cells were transfected with NLRP3 si RNA or MCC950 and/or treated with BC and/or LGR-1.NLRP3-si RNA transfection and MCC950 attenuated BC-induced NLRP3 inflammasome activity.Expression of inflammatory cytokines and cell death suggested that the inflammatory pathway might play an important role in the induction of the NLRP3 inflammasome by BC and the protection of LGR-1.Conclusions:These results suggest that LGR-1 might be a probiotic alternative to antibiotics and could be administered to prevent mastitis in dairy cows,thus ensuring food security.
文摘Rapid and accurate laboratory diagnosis of SARS-CoV-2 infection is crucial for the management of COVID-19 patients and control of the spread of the virus. At the start of the COVID-19 pandemic, Bangladesh had only one government molecular laboratory where real-time RT-PCR would be performed to diagnose SARS-CoV-2 infection. With the increasing number of suspected cases requiring confirmation diagnostic testing, there is a requirement to expand capacity for large-scale testing quickly. The government of Bangladesh established over 100 molecular laboratories within one year to test COVID-19. To expand the testing capacity, the government was compelled to recruit laboratory staff with limited experience and technical expertise, especially in molecular assays, to process specimens, interpret results, troubleshoot. As a result, the risk of diagnostic errors, such as cross-contamination, increased, potentially undermining the efficacy of public health policies, public health response, surveillance programs, and restrictive measures aimed toward containing the outbreak. In this piece, we discuss the different sources of cross-contamination in the COVID-19 RT-PCR laboratories and proffer practical preventive measures to avoid them.
基金supported by the National Natural Science Foundation of China(Nos.12174208,32227802)National Key Research and Development Program of China(No.2022YFC3400600)+3 种基金Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)China Postdoctoral Science Foundation(No.2020 M680032)Fundamental Research Funds for the Central Universities(Nos.2122021337,2122021405)the 111 Project(No.B23045).
文摘Cells are highly sensitive to their geometrical and mechanical microenvironment that directly regulate cell shape,cytoskeleton and organelle,as well as the nucleus morphology and genetic expression.The emerging two-dimensional micropatterning techniques offer powerful tools to construct controllable and well-organized microenvironment for single-cell level investigations with qualitative analysis,cellular standardization,and in vivo environment mimicking.Here,we provide an overview of the basic principle and characteristics of the two most widely-used micropatterning techniques,including photolithographic micropatterning and soft lithography micropatterning.Moreover,we summarize the application of micropatterning technique in controlling cytoskeleton,cell migration,nucleus and gene expression,as well as intercellular communication.
