ABSTRACT
OBJECTIVE: To establish a sensitive and specific PCR assay for detecting Schistosoma japonicum-infected Oncomelania hupensis. METHODS: Based on 18S-rRNA gene of S. japonicum, a PCR assay for detecting Oncomelania snails infected with S. japonicum was established. The PCR product was sequenced, and the sensitivity, cross-reaction and mass detection experiments of PCR assay were performed. RESULTS: The location of PCR product for detecting Oncomelania snails infected with S. japonicum was similar to the target DNA, with a length of 469 bp and the same sequence as the target DNA. It was registered in GenBank (Accession No. DQ442999). There was no PCR product for detecting uninfected snail. Experiments showed that the minimum DNA concentration of S. japoncium miracidium to be detected was 40 pg/Rpl. DNA from snail infected with single-tail cercaria could not be detected. The maximum dilution concentration of infected snail DNA pooled with uninfected snail DNA that could be detected was 1:640. CONCLUSION: The PCR assay for detecting S. japonicum-infected Oncomelania snails shows high sensitivity, specificity and effect of mass detection.
Subject(s)
Polymerase Chain Reaction/methods , Schistosoma japonicum/genetics , Snails/parasitology , Animals , Base Sequence , Molecular Sequence Data , RNA, Ribosomal, 18SABSTRACT
OBJECTIVE: To investigate the molecular mechanism of the effect of alcohol on insulin sensitivity. METHODS: Four groups of Wistar rats were used, i.e. control (C) group, and low (L), moderate (M) and high (H) alcohol group. Alcohol doses of each group were 0, 0.6, 1.8 and 3.0 ml.(kg.bw)(-1).day(-1). Each group was comprised of 10 male and 10 female rats. Alcohol was given to rats by gastric intubation. Thirteen weeks later, serum was collected for testing of fasting plasma glucose and insulin. HOMA-IR index of each group were calculated. Total muscle RNA was extracted using Trizol Reagent (Promega). The expression level of IRS-1 mRNA in muscle was detected by RT-PCR. RESULTS: In female rats, the fasting plasma glucose of group (8.36 +/- 0.57) mmol/L was higher and the fasting plasma insulin (15.25 +/- 3.32) was lower than those of group C (7.56 +/- 0.85, 20.80 +/- 3.25). The HOMA-IR of group L (1.775 3 +/- 0.138 1) was lower than that of group C (1.982 6 +/- 0.124 6) (P < 0.05), while IRS-1 mRNA (0.766 1 +/- 0.076 9) was up-regulated (P < 0.05); HOMA-IR of group M (2.202 2 +/- 0.271 0) was higher than that of group C (P < 0.01), while IRS-1 mRNA (0.501 8 +/- 0.049 2) was suppressed (P < 0.01); HOMA-IR of group H (1.850 1 +/- 0.162 8) was not significantly changed as compared with that of group C (1.982 6 +/- 0.124 6) (P > 0.05), while IRS-1 mRNA (0.418 1 +/- 0.049 1) was significantly suppressed (P < 0.01). In male rats, the fasting plasma glucose and insulin had the similar change as those of female rats. The HOMA-IR of group M (1.878 5 +/- 0.250 2) was lower than that of C group (2.147 3 +/- 0.330 8) (P < 0.05), IRS-1 mRNA was up-regulated (0.824 9 +/- 0.064 7) (P < 0.05). CONCLUSIONS: The present study showed that low-to-moderate dose of alcohol could increase insulin sensitivity; while alcohol abuse could decrease insulin sensitivity. Sex difference in this effect was found. Changes of IRS-1 mRNA expression may be involved in the molecular mechanism of the effects of alcohol on insulin sensitivity.
