OBJECTIVES: To detect prfA and hly toxin genes of Listeria monocytogenes using polymerase chain reaction (PCR) and colloidal gold technology. METHODS: L. monocytogenes DNA was extracted by boiling method. With prfA and hly of L. monocytogenes as the target genes, the 5' ends of upstream and downstream primers of prfA gene were labeled with 6-FAM and biotin, and the 5' ends of upstream and downstream primers of hly gene were labeled with digoxin and biotin, respectively, to establish the toxin gene detection method. Using cloning transformation, sequencing analysis, cloning of positive control products, the detection kid was developed and its specificity, sensitivity, reproducibility and stability were tested, followed by verification with sample testing. RESULTS: The concentration of L. monocytogenes DNA extracted by boiling method was 148.81±0.97 ng/μL, and the A₂₆₀/A₂₈₀ ratio ranged from 1.8 to 2.0. The PCR products showed a 100% homology with the gene sequences in GenBank database after cloning, transformation and sequencing. The colloidal gold strip yielded positive results only for L. monocytogenes samples without cross-reactions with Staphylococcus aureus, Escherichia coli or Bacillus cereus, and its minimum detection limit was 10^-2 ng/μL, demonstrating a 10-fold greater sensitivity of the test than agarose gel electrophoresis. The test also showed good reproducibility of the results when performed by different operators with good stability of the test strips after storage for 6 to 12 months. The test results showed that this kit could accurately and quickly detect L.monocytogenes in the test samples. CONCLUSIONS The detection kit developed in this study can simultaneously detect prfA and hly toxin genes of L. monocytogenes with good specificity, sensitivity, reproducibility and stability for use in food safety inspection.
Listeria monocytogenes/isolation & purification* ; Gold Colloid ; Bacterial Toxins/genetics* ; Polymerase Chain Reaction/methods* ; Hemolysin Proteins/genetics* ; Bacterial Proteins/genetics* ; DNA, Bacterial/genetics* ; Food Microbiology ; Heat-Shock Proteins

Objective To investigate the preventive therapeutic effect and possible mechanism of single chain variable fragments chimeric protein (SD) of ovalbumin epitopes internalizing receptor DEC-205 antibody on food allergy in mice. Methods Mice were randomly divided to five groups (control, PBS, scFv DEC 100 μg, SD 50 μg, SD 100 μg) and treated for 24 hours before OVA administration. After challenge, the serum level of OVA-specific IgE, IgG1, IgG2a and IL-4 were detected by ELISA. Infiltration of eosinophils and mast cells in the jejunum was observed by HE staining and toluidine blue staining respectively. The bone marrow of tibia and femur was isolated and cultured to obtain immature dendritic cells(BMDCs), which were further treated with LPS (10 ng/mL), TSLP (50 ng/mL), scFv DEC protein (1000 ng/mL) and SD protein (10,100,1000)ng/mL for 24 hours, and the IL-10 level of supernatant was assayed by ELISA. Results Compared with PBS group, the number of SD-treated mice with diarrhea was markedly reduced. The difference in rectal temperature and the levels of serum OVA-specific IgE, IgG1, IgG2a and IL-4 decreased significantly after prophylactic administration of SD; The number of eosinophils and mast cells in jejunum also decreased significantly while the IL-10 level in the supernatant of BMDCs increased significantly after SD intervention. Conclusion SD mitigates experimental FA response by fosters the immune tolerance property of dendritic cells.
Mice ; Animals ; Ovalbumin ; Interleukin-10 ; Single-Chain Antibodies/genetics* ; Immunoglobulin E ; Epitopes/therapeutic use* ; Interleukin-4 ; Food Hypersensitivity/prevention & control* ; Immunoglobulin G ; Recombinant Fusion Proteins/genetics* ; Mice, Inbred BALB C ; Disease Models, Animal

As an important zoonotic pathogen, Staphylococcus aureus has led to serious mastitis and endometritis in infected dairy cows. In this study, a total of 164 strains of S. aureus were isolated from dairy cows in Xinjiang Province, China, and subjected to assays to determine drug susceptibility and biofilm (BF) formation ability. Enterotoxin-related genes were detected, and the transcription levels of genes related to BF formation were determined by using reverse transcription-quantitative polymerase chain reaction. Moreover, the pathogenicity of isolates with different BF formation abilities was determined by measuring their hemolysis activity, half lethal dose (LD₅₀) and organ bacterial load. The results showed that 86.0% of S. aureus isolates could form BF. Among them, 42.1% of the strains had weak BF formation ability, and most strains with a strong BF formation ability were ica gene carriers. The S. aureus isolates displayed multidrug resistance and their drug resistance was positively correlated with their BF formation ability. Moreover, 96.3% of the S. aureus isolates carried enterotoxin genes. Among them, the detection rates of the novel enterotoxin genes were higher than those of conventional enterotoxin genes. Furthermore, isolates with a strong BF formation ability had higher LD50 but lower hemolysis ability and organ bacterial load than those of the isolates with weak or no BF ability. However, isolates without BF ability produced more severe pathological changes than those of isolates with strong BF formation ability. These findings suggest that higher BF ability and presence of novel enterotoxin genes are important characteristics of S. aureus isolates from dairy cows in Xinjiang Province, China, and such isolates may pose potential threats to food safety.
Bacterial Load ; Biofilms ; China ; Drug Resistance ; Drug Resistance, Microbial ; Drug Resistance, Multiple ; Endometritis ; Enterotoxins ; Female ; Food Safety ; Hemolysis ; Lethal Dose 50 ; Mastitis ; Polymerase Chain Reaction ; Staphylococcus aureus ; Staphylococcus ; Virulence

BACKGROUND: Osteoporosis is a geriatric disease with diminished bone density. The increase in the number of patients and medical expenses due to a global aging society are recognized as problems. Bone loss is the most common symptom of bone disease, not only osteoporosis but Paget's disease, rheumatoid arthritis, multiple myeloma, and other diseases. The main cause of this symptoms is excessive increase in the number and activity of osteoclasts. Osteoclasts are multinucleated giant cells that can resorb bone. They are differentiated and activation from monocytes/macrophages in the presence of macrophage colony-stimulating factor and receptor activator of nuclear factor-κB ligand (RANKL). METHODS: The effect of extract of Flavoparmelia sp. (EFV), a genus of lichenized fungi within the Parmeliaceae, on the differentiation of bone marrow-derived macrophages (BMMs) into osteoclasts was examined by phenotype assay and the cell cytotoxicity was evaluated by cell counting kit-8. The osteoclast differentiation-related genes and proteins were investigated by real-time polymerase chain reaction and immunoblotting. The functional activity of osteoclast in response to EFV treatment was evaluated by an Osteo Assay plate. RESULTS: In this study, we found that EFV, a genus of lichenized fungi within the Parmeliaceae, inhibited osteoclast formation. And we investigated its inhibitory mechanism. EFV reduced RANKL-mediated osteoclast formation and activation by inhibiting expression of nuclear factor of activated T cells 1, a key factor of osteoclastogenesis. CONCLUSIONS: Taken together, our results show that EFV is a promising candidate for health functional foods or therapeutic agents that can help treat bone diseases such as osteoporosis.
Aging ; Arthritis, Rheumatoid ; Bone Density ; Bone Diseases ; Cell Count ; Functional Food ; Fungi ; Giant Cells ; Humans ; Immunoblotting ; Lichens ; Macrophage Colony-Stimulating Factor ; Macrophages ; Multiple Myeloma ; NFATC Transcription Factors ; Osteoclasts ; Osteoporosis ; Parmeliaceae ; Phenotype ; Real-Time Polymerase Chain Reaction ; T-Lymphocytes

The liver is an essential organ for the detoxification of exogenous xenobiotics, drugs and toxic substances. The incidence rate of non-alcoholic liver injury increases due to dietary habit change and drug use increase. Our previous study demonstrated that Ecklonia stolonifera (ES) formulation has hepatoprotective effect against alcohol-induced liver injury in rat and tacrine-induced hepatotoxicity in HepG2 cells. This present study was designated to elucidate hepatoprotective effects of ES formulation against carbon tetrachloride (CCl₄)-induced liver injury in Sprague Dawley rat. Sixty rats were randomly divided into six groups. The rats were treated orally with ES formulation and silymarin (served as positive control, only 100 mg/kg/day) at a dose of 50, 100, or 200 mg/kg/day for 21 days. Seven days after treatment, liver injury was induced by intraperitoneal injection of CCl₄ (1.5 ml/kg, twice a week for 14 days). The administration of CCl₄ exhibited significant elevation of hepatic enzymes (like AST and ALT), and decrease of antioxidant related enzymes (superoxide dismutase, glutathione peroxidase and catalase) and glutathione. Then, it leaded to DNA damages (8-oxo-2′-deoxyguanosine) and lipid peroxidation (malondialdehyde). Administration of ES formulation inhibited imbalance of above factors compared to CCl₄ induced rat in a dose dependent manner. Real time PCR analysis indicates that CYP2E1 was upregulated in CCl₄ induced rat. However, increased gene expression was compromised by ES formulation treatment. These findings suggests that ES formulation could protect hepatotoxicity caused by CCl₄ via two pathways: elevation of antioxidant enzymes and normalization of CYP2E1 enzyme.
Animals ; Carbon Tetrachloride ; Cytochrome P-450 CYP2E1 ; DNA Damage ; Food Habits ; Gene Expression ; Glutathione ; Glutathione Peroxidase ; Hep G2 Cells ; Incidence ; Injections, Intraperitoneal ; Lipid Peroxidation ; Liver* ; Rats ; Rats, Sprague-Dawley* ; Real-Time Polymerase Chain Reaction ; Silymarin ; Xenobiotics

BACKGROUND: Endothelial adhesion molecule expression induced by pro-inflammatory cytokine plays an important role in vascular endothelial cell injury, leading to vascular disease. Allium tuberosum (AT), which is used as a functional food, has a thrombolytic effect. It contains vitamin A, vitamin C, carbohydrate, calcium, iron, and phosphorus. There are many carotenes that turn into vitamin A in the body. Also, it helps blood circulation and stimulates metabolism. The purpose of the this study was to estimate the anti-inflammatory effects of the AT extract. METHODS: Human vascular endothelial cells were pre-treated with 100 μg/mL AT extract for 30 minutes and subsequently co-treated with TNF-α (10 ng/mL) and AT extract (100 μg/mL) for 1, 4, and 6 hours. After treatment, the cells were lysed and used for quantitative reverse transcription PCR, Western blot analysis, and monocyte adhesion assay. RESULTS: We examined the effect of the AT extract on inflammatory gene expression in TNF-α-induced human umbilical vein endothelial cells (HUVECs). The extract reduced the expression levels of mRNA and protein of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 in TNF-α-stimulated HUVECs. It also inhibited the TNF-α-induced phosphorylation of the NF-κB p65 subunit and degradation of IκBα. Furthermore, the AT extract prevented the increased adhesion capacity of monocyte to TNF-α-stimulated vascular endothelial cells by reducing ICAM-1 and VCAM-1 expression. CONCLUSIONS: The AT extract has preventive and anti-inflammatory effect against vascular disease and has potential for supporting prevention against the early process of atherosclerosis.
Allium* ; Ascorbic Acid ; Atherosclerosis ; Blood Circulation ; Blotting, Western ; Calcium ; Carotenoids ; Chive* ; Endothelial Cells* ; Functional Food ; Gene Expression ; Human Umbilical Vein Endothelial Cells ; Humans* ; Inflammation* ; Intercellular Adhesion Molecule-1 ; Iron ; Metabolism ; Monocytes ; Necrosis* ; NF-kappa B ; Phosphorus ; Phosphorylation ; Polymerase Chain Reaction ; Reverse Transcription ; RNA, Messenger ; Vascular Cell Adhesion Molecule-1 ; Vascular Diseases ; Vitamin A

BACKGROUND/AIMS: Colorectal cancer (CRC) screening using stool DNA was recently found to yield good detection rates. A multi-target stool DNA test (Cologuard®, Exact Sciences), including methylated genes has been recently approved by the U.S. Food and Drug Administration. The aim of this study was to validate these aberrantly methylated genes as stool-based DNA markers for detecting CRC and colorectal advanced adenoma (AA) in the Korean population. METHODS: A single-center study was conducted in 36 patients with AA; 35 patients with CRC; and 40 endoscopically diagnosed healthy controls using CRC screening colonoscopy. The methylation status of the SFRP2, TFPI2, NDRG4, and BMP3 promoters was investigated blindly using bisulfate-modified stool DNA obtained from 111 participants. Methylation status was investigated by methylation-specific polymerase chain reaction. RESULTS: Methylated SFRP2, TFPI2, NDRG4, and BMP3 promoters were detected in 60.0%, 31.4%, 68.8%, and 40.0% of CRC samples and in 27.8%, 27.8%, 27.8%, and 33.3% of AA samples, respectively. The sensitivities obtained using 4 markers to detect CRC and AA were 94.3% and 72.2%, respectively. The specificity was 55.0%. CONCLUSIONS: Our results demonstrate that the SFRP2, TFPI2, NDRG4, and BMP3 promoter methylation analysis of stool sample DNA showed high sensitivity but low specificity for detecting CRC and AA. Because of the low specificity, 4 methylated markers might not be sufficient for CRC screening in the Korean population. Further large-scale studies are required to validate the methylation of these markers in the Asian population and to find new markers for the Asian population.
Adenoma ; Asian Continental Ancestry Group ; Colonoscopy ; Colorectal Neoplasms* ; DNA ; Feces ; Genetic Markers ; Humans ; Mass Screening* ; Methylation* ; Polymerase Chain Reaction ; Sensitivity and Specificity ; United States Food and Drug Administration

Animals ; Chickens ; microbiology ; Cross-Sectional Studies ; Enterobacteriaceae ; genetics ; isolation & purification ; Escherichia coli ; genetics ; isolation & purification ; Escherichia coli Proteins ; genetics ; Food Microbiology ; Klebsiella pneumoniae ; genetics ; isolation & purification ; Meat ; microbiology ; Multiplex Polymerase Chain Reaction ; Proteus mirabilis ; genetics ; isolation & purification ; Raw Foods ; microbiology ; Singapore ; beta-Lactamases ; genetics

BACKGROUND: Rotavirus is the leading cause of acute viral gastroenteritis, particularly in children, and is transmitted through the fecal-to-oral route by contaminated food or the environment. This study examined the contamination of the inner surfaces of domestic refrigerators with pathogens causing gastroenteritis. METHODS: Swab specimens from shelf surfaces of freezers and refrigerators were collected from 10 domestic refrigerators. Multiplex PCR for bacterial and viral pathogens causing acute gastroenteritis was performed. The VP7 and VP4 genes of rotavirus were amplified and then analyzed by DNA sequencing. RESULTS: Rotavirus was detected in five domestic refrigerators in the same apartment complex. All rotavirus samples showed the G1 genotype and the same DNA sequences. No pathogens causing acute gastroenteritis were identified in the other five domestic refrigerators. CONCLUSIONS: The inner surfaces of domestic refrigerators can be contaminated with pathogens causing acute gastroenteritis, such as rotavirus. Attention should be given to the hygiene of refrigerators. To estimate the contamination or hygienic status for food storage, testing for viral pathogens combined with ordinary bacterial cultures may be necessary.
Base Sequence ; Child ; Food Storage ; Foodborne Diseases ; Gastroenteritis ; Genotype ; Humans ; Hygiene ; Multiplex Polymerase Chain Reaction ; Rotavirus* ; Sequence Analysis, DNA

OBJECTIVETo establish a method for detecting 3 common toxigenic molds (Aspergillus, Penicillium, and Fusarium) based on non-modified magnetic beads coupled with multiple real-time PCR (NMB-multiple qPCR).

METHODSThe primers and genus-specific probes were designed based on the rDNA sequences to develop a multiple real-time PCR using non-modified magnetic bead to enrichment of fungal spores. The sensitivity, specificity and repeatability of this assay were evaluated.

RESULTSThe detection limit of this assay for spiked samples was 10(4) CFU/g, demonstrating a 10-fold greater detection sensitivity of this assay than that of real-time PCR. The NMB-multiple qPCR assay also showed good specificity and reproducibility and yielded comparable results with those by traditional colony counting method for spiked samples (P>0.05).

CONCLUSIONNMB-multiple qPCR assay we established allows rapid and sensitive detection of common mycotoxigenic fungi in paprika.

Aspergillus ; Capsicum ; microbiology ; DNA Primers ; Food Contamination ; analysis ; Food Microbiology ; Fungi ; isolation & purification ; Fusarium ; Magnetic Phenomena ; Penicillium ; Real-Time Polymerase Chain Reaction ; methods ; Reproducibility of Results ; Sensitivity and Specificity