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Yuan J.,Jiangnan University | Yu Y.,Zhangjiagang Entry Exit Inspection and Quarantine Bureau | Li C.,Jiangnan University | Ma X.,Jiangnan University | And 3 more authors.
Microchimica Acta | Year: 2014

We have developed a specific method for the visual detection of Staphylococcus aureus based on aptamer recognition coupled to tyramine signal amplification technology. A biotinylated aptamer specific for S. aureus was immobilized on the surface of the wells of a microplate via biotin-avidin binding. Then, the target bacteria (S. aureus), the biotinylated-aptamer-streptavidin-HRP conjugates, biotinylated tyramine, hydrogen peroxide and streptavidin-HRP were successively placed in the wells of the microplate. After adding TMB reagent and stop solution, the intensity of the yellow reaction product can be visually inspected or measured with a plate reader. Under optimized conditions, there is a linear relationship between absorbance at 450 nm and the concentration of S. aureus in the 10 to 107 cfu mL-1 concentration range (with an R2 of 0.9976). The limit of detection is 8 cfu mL-1. [Figure not available: see fulltext.] © 2013 Springer-Verlag Wien. Source

Lu S.,Nanjing Normal University | Lu S.,Nanjing University of Technology | Lu S.,University of Georgia | Purohit S.,University of Georgia | And 10 more authors.
International Journal of Clinical and Experimental Medicine | Year: 2012

Insulin-like growth factor binding proteins (IGFBPs) are associated with insulin resistance and accelerated micro-and macro-vascular complications of diabetes. We investigated the relationship between serum levels of IGFBP6 in type-1 diabetes (T1D) patients and diabetic complications. In this study, IGFBP6 was measured in the sera from 697 T1D patients and 681 healthy controls using a Luminex assay. Mean serum levels of IGFBP6 were higher in T1D patients than controls matched for sex and age (119.7 vs 130.6 ng/ml, p < 10-4). Subject age, sex and duration of disease have a significant impact on serum IGFBP6 levels in both T1D patients and healthy controls. Patients with complications have significantly higher mean serum IGFBP6 than patients without any complication (p = 3.5×10-6). More importantly, conditional logistic regression analysis suggested that T1D patients are more likely to have very high levels of serum IGFBP6 (in the 4th quartile) (OR = 1.7) than healthy controls. Furthermore, T1D patients with various complications are more likely to have very high levels of serum IGFBP6 (in the 4th quartile) than patients without any complication (OR = 1.7-22.9). These results indicate the clinical importance of measuring IGFBP6 to the better management of T1D patients. Source

Yuan J.,Jiangnan University | Tao Z.,Jiangnan University | Yu Y.,Zhangjiagang Entry Exit Inspection and Quarantine Bureau | Ma X.,Jiangnan University | And 3 more authors.
Food Control | Year: 2014

A rapid, specific and visible detection method for Salmonella Typhimurium was developed based on the recognition of aptamers coupled with nanogold labeling and silver signal amplification. Briefly, biotinylated aptamer 1, which was specific to Salmonella Typhimurium, was immobilized onto the surface of microtiter plate-wells modified with streptavidin through the binding of biotin and streptavidin. Then, the target bacteria, Salmonella Typhimurium, and the aptamer 2-gold nanoparticle (aptamer 2-AuNPs) conjugates were incubated in the wells to form sandwich-type aptamer/bacteria/aptamer-AuNPs complexes. Under optimal conditions, the correlation between the concentration of Salmonella Typhimurium and the intensity of the signals was observed to be linear within the range of 10-106cfumL-1 (R2=0.9913), and the detection limit of the proposed method was observed to be 7cfumL-1 This developed method offers the potential for rapid, sensitive and visible detection of Salmonella Typhimurium in samples. © 2013 Elsevier Ltd. Source

Shao J.D.,Zhangjiagang Entry Exit Inspection and Quarantine Bureau
Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi = Chinese journal of parasitology & parasitic diseases | Year: 2012

The special DnaJ-like protein gene of Cryptosporidium parvum was amplified through designing special primers and TaqMan probes within the conserved and specific regions for this gene. method of real-time PCR assay for the detection of C. parvum was established. The specificity and sensitivity of PCR were also analyzed. By adding standard culture fluid in blank fecal sample, the sensitivity of the method was evaluated. The results showed that the detection limit of pure culture with real-time PCR assay was 26 oocysts/ml. The detection limit for C. parvum in artificially contaminated fecal sample was 2 600 oocysts/ml. The specificity of the method was verified with no amplification on DNA from other enteric parasites and bacteria. These results indicated that the real-time PCR method for C. parvum detection in fecal sample is simple, rapid, with high specificity and sensitivity. Source

Duan N.,Jiangnan University | Wu S.,Jiangnan University | Yu Y.,Zhangjiagang Entry Exit Inspection and Quarantine Bureau | Ma X.,Jiangnan University | And 4 more authors.
Analytica Chimica Acta | Year: 2013

A sensitive, specific method for the collection and detection of pathogenic bacteria was demonstrated using quantum dots (QDs) as a fluorescence marker coupled with aptamers as the molecular recognition element by flow cytometry. The aptamer sequences were selected using a bacterium-based SELEX strategy in our laboratory for Vibrio parahaemolyticus and Salmonella typhimurium that, when applied in this method, allows for the specific recognition of the bacteria from complex mixtures including shrimp samples. Aptamer-modified QDs (QD-apt) were employed to selectively capture and simultaneously detect the target bacteria with high sensitivity using the fluorescence of the labeled QDs. The signal intensity is amplified due to the high photostability of QDs nanoparticles, resulting in improved sensitivity over methods using individual dye-labeled probes. This proposed method is promising for the sensitive detection of other pathogenic bacteria in food stuff if suitable aptamers are chosen. The method may also provide another potential platform for the application of aptamer-conjugated QDs in flow cytometry. © 2013 Elsevier B.V. Source

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