ABSTRACT
Objective To establish a method for simultaneous detection of norovirus (NV),rotavirus (RV), astrovirus (AV) and hepatitis A virus (HAV) by multiplex reverse transcriptionpolymerase chain reaction (RT-PCR). Methods Specific primers of the four viruses were designed based on the high conserved sequences, the reaction system and conditions optimized and the specificity and sensitivity confirmed. The method was then applied to detect the four viruses in clinical samples. Results The steady detection limits were 100 pg/ml for hepatitis A virus, 50 pg/ml for rotavirus, norovirus and astrovirus respectively. When the developed method was used to detect clinical fecal samples, 62(48.44%)were iden tified as rotavirus, 8 (6.25%) as norovirus, 11 (8.59%) as astrovirus and 4 (3.12%) as hepatitis A virus in a total of 128 samples. Conclusion Data from our study showed that multiplex RTPCR system could be used to simultaneously detect the four viruses in routine monitoring and risk assessment in disease outbreaks with high specificity and sensitivity.
ABSTRACT
In this assay, the reaction kinetics, optimum temperature, pH and various influential factors of ATP microbial rapid detection reagent by bioluminescence were studied. The results showed that it's enough for detection system to have 40 ~ 50?g/mL D-Luciferin. The light production decreased fastest in the first minute of reaction, then began to decay slowly. The optimal reaction temperature was 24℃~25℃and the optimal pH was pH 7.2 -7.4 in the reaction system. In addition, when stored at 4℃for 45h, the dissolved reagent solution could keep its 86% activity. When preserved at 25℃, the enzyme activity decreased less for 1h, and degraded gradually as time went by and only left 53. 5% of its activity after 6. 5h. While stored at 33℃, the enzyme activity decreased quickly with the time and only left 59. 1% after 1. 5h. The result indicated that storage temperature was a very important influential factor to the activity of reagent Meanwhile, different chemical substance such as acid, alkali, salt and surfactants inhibited the ATP bioluminescent reaction. When the concentration of NaCl reached 1. 5g/L, it could inhibit 52. 5% light production. Triton X-100, acid, and alkali also had some effects on the reaction, while CTAB, SDS and TCA would inhibit the bioluminescent reaction seriously.
ABSTRACT
Foodbome viruses are defined to be viruses that can lead to human diseases through food. In accordance with the different origin, foodborne viruses can be divided into two kinds: intestinal viruses and zoonotic viruses. The former include those viruses that can be transmitted to person via fecal-orally route. The latter include those zoonotic viruses that chiefly transmitted to person through livestock and poultry products. This paper expounds foodborne viruses categories, biology nature, epidemiology character, and study circumstance, and clarifies the molecular biological methods and problems on the base of the polymerase chain reactions, and presents the development direction and application perspective of the foodbome viruses study.
ABSTRACT
The brown slime inside pipeline of the polluted mineral waters well was analyzed. It was confirmed that the brown slime was a biofilm formed mainly by growth of bacteria contaminant, using microscope analysis. After treated with HCl, the brown crystals and mycelioid matter presented in slimes disappeared. It was verified these were metal deposits. The samples produced Prussia blue deposits by dropping K 4Fe(CN) 6 and HCl, which proved that the metal deposits were iron compound. Also it was believed the biofilm was produced by growth of iron bacteria, mixed with deposits of iron compound. The iron bacteria have been isolated from the slimes and cultured in the laboratory. The colony on agar plate also produced Prussia blue deposits after treated with K 4Fe(CN) 6 and HCl. The cells form of pure culture was the same as that in the samples by electronmicroscope analysis. Therefore, It indicated that the bacteria on biofilm inside pipeline were iron bacteria mainly.