RESUMO
Objective:To quantitatively analyze the changes of Staphylococcus aureus in different processed products of Angelicae Sinensis Radix. Method:The real-time fluorescence quantitative polymerase chain reaction method （Real-time PCR） was established to quantitatively analyze S. aureus in Angelicae Sinensis Radix decoction pieces which bought from different producing areas， different enterprises and different storage time. The fluorescence quantitative reaction system was SYBR Premix Ex Taq Ⅱ of 10 μL， each of forward primer and reverse primer （10 μmol·L-1） of 0.8 μL， template/genome DNA of 1 μL， double distilled water of 7.4 μL. The reaction conditions of the fluorescence quantitative amplification curve were pre-denaturing for 30 s at 94 ℃， denaturing for 10 s at 94 ℃， annealing for 12 s at 60 ℃， extensing for 30 s at 72 ℃， cycling 45 times， single-point detection signal at 72 ℃. The melting curve was made from 72 ℃， and the step temperature of 0.5 ℃ was kept for 15 s to collect fluorescence. According to the results of Real-time PCR， representative samples were selected from Angelicae Sinensis Radix decoction pieces for comparison between plate counting method and Real-time PCR. Result:The content of S. aureus in different processed products was sorted by rank of raw Angelicae Sinensis Radix>soil-fried Angelicae Sinensis Radix>wine-processed Angelicae Sinensis Radix. The content of S. aureus was the lowest in the samples from Weiyuan area of Gansu province by comparing with other producing areas. Compared with the retail enterprises， the content of S. aureus in raw products and wine-processed products from production and sale enterprises was lower. Different storage time had certain effect on the content of S. aureus in raw products and wine-processed products， and the content of S. aureus increased with the increase of storage time. The detection results of plate counting method were 3-4 orders of magnitude lower than that of Real-time PCR. Conclusion:The established Real-time PCR is superior to plate counting method in specificity， sensitivity， reliability and reporting period， which can provide an effective method for rapid and accurate quantitative detection of S. aureus in different processed products of Angelicae Sinensis Radix.
RESUMO
[ Objective ] To screen the duck model with congenital infection of duck hepatitis B virus (DHBV) by polymerase chain reaction (PCR) method. [Methods] Serum DHBV-DNA level in one-day-old ducklings was detected by PCR method and was compared with that by Dot-blot method. Ducklings with serum DHBV-DNA being negative confirmed by PCR method were inoculated DHBV-DNA positive serum to establish acquired infection models. Pathological features of liver tissues in the congenital infec tion model and the acquired infection model were also observed. [Results] Sensitivity and specificity of PCR detecting serum DHBV-DNA were superior to those of Dot-blot method. In the congenital infection model, viremia maintained long time, the titer of serum DHBV-DNA was high and the inflammatory af fection in liver tissues was slight as compared with those in the acquired infection model. [Conclusion] The duck model with congenital infection of DHBV screened by PCR method is more suitable for the phar macological and pharmacodynamic research of drugs for chronic hepatitis B.