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ABSTRACT: Staphylococcus aureus causes foodborne diseases if consumed in contaminated milk products. Rapid detection and characterization of foodborne pathogen S. aureus is crucial for epidemiological investigations and food safety surveillance. It is still a challenge to detect and identify bacterial pathogens quickly and accurately according to the samples. In this study, we have amplified 16S rRNA of S. aureus by specific primers, designed oligonucleotide probes, detected the sensitivity and specificity of the microarray assay, and also identified S. aureus in the raw milk samples by hybridization. The S. aureus and 2 control pathogens (Streptococcus suis in pigs and Shigella) were used for specificity of the microarray assay. Based upon the hybridization results, universal probes for bacterial pathogens, S. aureus probe, Staphylococcus spp. probe, nucleic acid fixture positive controls and positive experimental control showed positive signals with targeted S. aureus. The samples were diluted from 10 1 to 10 6 cfu per ml for evaluating the sensitivity of the microarray assay. The levels were as high as 10 3 cfu per ml, all of the samples showed positive signals. This method for rapid and effective detection and identification of S. aureus in raw milk demonstrated high sensitivity and specificity.
AFRICAN JOURNAL OF BIOTECHNOLOGY 05/2010; 9:2284-2289. · 0.57 Impact Factor
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ABSTRACT: Aging effect on the mobility and bioavailability of copper (Cu) was investigated using a spiked soil with different incubation periods from 3 to 56 d. Wheat was planted and earthworms were cultured separately in the incubated soils. The mobility of Cu in soil was evaluated by a chemical fractionation scheme and the toxicity and bioavailability were assessed by measuring the biomass and Cu concentration in tissues. Results showed that aging had a significant effect on Cu fraction distribution, of which Cu tended to incorporate from the exchangeable into more stable fractions such as the reducible and oxidisable fractions. However, aging had little effect on Cu bioavailability to wheat and earthworm. Comparing the soil being incubated for 3 d and 56 d, Cu concentration in wheat roots decreased from 14.5 to 12.8 mg/kg, and no significant changes in Cu concentration were observed in both wheat shoots and earthworms. The Cu concentration was around 2.0 and 50 mg/kg for wheat shoots and earthworms, respectively, irrespective of soil incubation time. The CaCl2-extractable Cu had a linear relationship with Cu concentration in wheat roots (R2 = 0.65, P < 0.05), but no linear relationship can be found for wheat shoots and earthworms. Biological control may be more crucial for Cu accumulation in organism than the changes in soil Cu fraction caused by aging.
Journal of Environmental Sciences 01/2009; 21(2):173-8. · 1.66 Impact Factor
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ABSTRACT: To establish the rapid detection method of Enterotoxigenic E. coli (ETEC) by polymerase chain reaction (PCR) technology for characteristic primers.
The primer of LT gene from Enterotoxigenic E. coli was designed and the condition of PCR was optimized to identify ETEC with PCR amplification for 16 samples.
all samples could not be amplified except ETEC with special primer.
The technology of ETEC determinated by PCR could be easy, rapid and accurate.
Wei sheng yan jiu = Journal of hygiene research 04/2008; 37(2):231-3.
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ABSTRACT: To evaluate the influences of sewage sludge-derived organic matters on metal sorption and on the resultant sludge loading estimates, a batch experiment was conducted to compare the sorption of Ni, Cu and Pb in sewage sludge filtrates (1:20 sewage sludge to water) on eight soils and the adsorption of metals in a reference solution which had the same matrix as the sewage sludge filtrate except dissolved organic material (henceforth referred to as reference solution). Metal sorption could be well fitted by linear isotherm and the dissolved organic matter in sludge significantly depressed the sorption (p<0.01). The main factor controlling sorption of Ni on different soils was dominated by soil cation exchange capacity (CEC) and sorption of Cu and Pb was by soil organic matter (SOM). The parameters obtained from the sorption isotherm equations were then used to estimate sludge loadings into the soils. When the sorption parameters derived from the reference solution were used for calculation, that is the effect of dissolved organic matter was not considered, the calculated safe application rates are approximately 47.8, 51.4, 34.2, 31.3, 21.7, 46.3, 187.1 and 27.6 t-sludge/ha for the Beijing, Jiangxi, Xiamen, Jilin, Guangdong, Wuhan, Gansu and Xinjiang soils, respectively. However, when the sorption parameters derived from the dissolved organo-metallic complexes are used for calculation, the corresponding application rates are reduced to approximately 6.0, 3.4, 1.9, 10.0, 6.3, 3.6, 7.3 and 3.5 t-sludge/ha, respectively. By this study we can get a conclusion that the effect of sewage sludge derived dissolved organic matter on heavy metal sorption and soil properties should be considered in the course of regulating the safe application rates of sewage sludge to soil.
Journal of Hazardous Materials 10/2007; 149(2):399-407. · 4.17 Impact Factor
