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ObjectiveThe contamination of foodborne pathogens in ready-to-eat fruits and vegetables in Shanghai was analyzed to provide a scientific basis for food safety， risk assessment and related supervision. MethodsFrom June to September 2021， a total of 143 batches of12 kinds of ready-to-eat fruits and vegetables such as lettuce， chicory， and cherry tomatoes were collected from farmers’ markets， supermarkets， and e-commerce platforms. The total number of bacterial colonies， Salmonella， Listeria monocytogenes， Staphylococcus aureus， Cronobacter spp. and Shiga toxin-producing Escherichia coli in the samples were tested according to National Food Contamination and Harmfulness Risk Monitoring Manual. ResultsAmong the 143 batches， foodborne pathogens were detected in 68 batches， with a total detection rate of 47.55% （68/143）. A total of 79 strains of foodborne pathogens were detected. The detection rate of Staphylococcus aureus was the highest （32.87%， 47/143）， followed by Cronobacter spp. （20.98%， 30/143）， Salmonella （0.70%， 1/143）， Listeria monocytogenes （0.70%， 1/143）， Shiga toxin-producing Escherichia coli （0.00%）. Furthermore， the detection rate was higher in different ready-to-eat fruits and vegetables： chicory （17.33%）， cucumber （17.14%）， cherry tomatoes （16.00%）， and honeydew melon （15.38%）， respectively. Meanwhile， the contamination rate of pathogens in ready-to-eat fruits and vegetables from farmers’ markets， supermarkets， and e-commerce platforms was relatively high. ConclusionReady-to-eat fruits and vegetables in Shanghai are contaminated by foodborne pathogens. The prevention and control of the contamination of post-harvest fruits and vegetables should be strengthened to reduce the risk of foodborne disease outbreaks.
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Quorum sensing (QS) plays a major role in the outbreak mechanism of foodborne diseases caused by food poisoning and food spoilage. QS affects the formation of cell membrane and pathogenicity ofpathogenic bacteria. Through the in-depth understanding of QS molecules of food-borne pathogens, we describe here the types of signal molecules produced by Gram-negative and Gram-positive bacteria, and the differences in QS molecules. Meanwhile, we introduce the detection of QS molecules by different technologies. According to the influence of QS on food, we propose also future research needs for the control of foodborne pathogenic bacteria.
Subject(s)
Gram-Negative Bacteria , Gram-Positive Bacteria , Quorum SensingABSTRACT
Objective:To investigate characteristic expression of TGF-?1 in human ADPKD and clarify its role in the development and progression of human ADPKD. Methods:Cyst fluid, urinary and plasma TGF-?1 levels were determined by ELISA in 39 ADPKD patients. The results were compared with those of normal subjects and of patients with simple renal cyst. TGF-?1, TGF-?1 receptors types Ⅰ, types Ⅱ, CTGF mRNA and proteins in the kidneys of human ADPKD were examined by in situ hybridization and immunohistochemistry. The relationship of the above fibrosing-associated indicators with the degree of interstitial fibrosis was analyzed. Results:Plasma TGF-?1 level was the highest among body fluids. In ADPKD and simple renal cyst, TGF-?1 levels were significantly higher than those in normal subjects (15.12 ?8.53)?g/L vs (5.41?1.31) ?g/L,P
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Objective To prepare and identify monoclonal antibody against LRR-WSC domain of polycystin-1 and to investigate the distribution of polycystin-1 in kidney tissues and kidney cell lines. Methods BALB/c mice were immunized with fusion protein PC1-e of polycystin-1 LRR-WSC domain. The splenocytes were fused with myeloma cells by PEG 4000 and the hybridomas were selected in HAT medium. The hybridoma clones secreting antibodies against polycystin-1 LRR-WSC domain were detected by enzyme-linked immunosorbent assay ( ELISA) and cloned by limiting dilution. The specificity of anti-polycystin-1 LRR-WSC domain monoclonal antibody from hybridoma was verified by ELISA and Western blot. The distribution of polycystin-1 in tissues and cells was detected by immunohistochemical method. Results One cell line of hybridoma secreting monoclonal antibody against polycystin-1 was established. Western blot analysis showed that the monoclonal antibody reacted strongly and specifically to polycystin-1 LRR-WSC domain. Distribution of polycystin-1 in fetal kidney was localized in tubular epithelium. In normal adult kidney tissues, our study showed that polycystin-1 was mainly expressed in the medullary collecting ducts and distal convoluted tubules. Positive staining was also found in the majority of cyst-lining epithelial ceEs of cystic tissue from autosomal dominant polycystic kidney disease ( ADPKD) patients. Expressions of polycystin-1 were found in either ADPKD cyst-lining epithelia cell line and LLC-PK1, clearly plasma membrane and intracytoplasmic staining of polycystin-1 were observed. Conclusion Specific monoclonal antibody against polycystin-1 LRR-WSC domain were obtained. The antibody is important to researching the mechanism of ADPKD. The distribution of polycystin-1 in kidney tissues and cells show that polycystin-1 was important in tubular elongation and the maintenance of tubular architecture.
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Objective To investigate the correlation of serum sFasL level with carotid arterial intima- media thickness(IMT) and some known markers of inflammation, nutritional status in uremic patients with cardiovascular disease(CVD). Methods 134 uremic patients on hemodialysis were divided into two groups, CVD group (n=103) and non-CVD group (n=31). The serum level of sFasL, C-reactive protein (CRP), IL-6, TNF-? and albumin were measured by enzyme-linked immunosorbent assays (ELISA). The expression of Fas and FasL in radial arterial endothelial cells were observed both by immuohistochemical stain and by reverse transcription- polymerase chain reaction (RT-PCR). The Carotid arterial IMTs were measured by Color doppler ultrasonography. Results Compared with the non-CVD group, CVD group showed significantly increased serum sFasL, CRP, IL-6, and TNF-?, and decreased serum albumin(P
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Objective To investigate the effect of taurine on proliferation and apoptosis of rat mesangial cells cultured in vitro and explore its possible mechanism. Methods Rat mesangial cells were incubated with different concentration of taurine. Cell proliferation was assessed by MTT colorimetric assay. Cell cycle and apoptosis was analyzed by flow cytometry. Form of apoptosis was examined by vital staining of alcidine orange. The expression of c-jun and c-fos was determined by immunocytochemistry and computed video text analysis system. Results Administration of 5 ~ 50 mmol/L taurine into culture medium had no loxicity to mesangial cells, but could significantly inhibit mesangial cells proliferation in dose-dependent manner, subsequently increased the cells in Go/Gi phase and decreased the cells in S phase. In addition, turine could markedly inhibit the expression of c-jun and c-fos( P
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Objective:To construct a mutispecific internal control for competitive RT-PCR analysis of Fas、FasL、GB、P、TIA-1 and ?-actin.Methods:Invitro synthesized fragments were amplified by PCR,there are two products,of which 145 and 147 bp.The 145 bp one contained 5′ primer sequences of Fas、FasL、GB、P、TIA-1 and ?-actin,another contained 3′ primer sequences of the same genes.The products with restriction sites were inserted into the vector PKF_3.Results:Restriction enzyme analysis and DNA sequencing were used to identify the recombinant plasmid,corresponding internal control was obtained by the amplification of the recombinant plasmid with each primer pair.The mutispecific internal control was then used for quantitative detection of TIA-1 in peripheral blood leukocytes from a patient with acutely rejecting allograft.Our study on Fas、FasL、GB、P、TIA-1 and ?-actin showed that the coamplified templates accumulated in a parallel manner throughout not only the exponential phase.Conclusion:The mutispecific internal control can be used for quantitative detection of the six genes. [
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Objective To investigate the concentration of secreted protein acidic and rich in cysteine (SPARC) in body fluid of patients with autosomal dominant polycystic kidney disease (ADPKD) and the origin of its secretion. Methods The concentration of SPARC in plasma, urine and cystic fluid from patients with ADPKD and healthy individuals was measured with ELISA. The content of SPARC protein in the culture medium of cystic epithelial cells was detected by Western blot. Results The concentration of SPARC in cyst fluid of ADPKD patients [( 3 628.75? 1 445.90) ng/ml] was much higher than that in their plasma and urine (P