Construction of a synthetic vector for preparation of a 100 base pair DNA ladder

DNA size markers are widely used to estimate the size of DNA samples on agarose or polyacrylamide gel electrophoresis [PAGE]. DNA markers can be prepared by mixing PCR products with definite sizes. Alternatively, they are prepared by restriction enzyme digestion of the genomic DNA of bacteriophages or natural and synthetic DNA plasmids. The present study describes engineering of a synthetic plasmid which produces a 100 bp DNA ladder, a popular DNA size marker, upon digestion with a single restriction enzyme. Our strategy consisted on sequential cloning of ten PCR products of 100 to 1000 bp in plasmid pTZ57R, using the BamHI and Bg/II restriction sites and releasing the fragments from the recombinant plasmid by enzyme EcoRV. This strategy could be applied to construct various complex synthetic vectors to produce different DNA ladders

Effects of teucrium polium ethyl acetate extract on serum, liver and muscle triglyceride content of sucrose-induced insulin resistance in rat

Possessing putative hypolipidemic effects, Teucrium polium [TP] have been traditionally used as a medicinal plant in Iran. The aim of the present study was to investigate this effect on the sucrose-induced insulin resistance male rat model. Thirty Wistar male rats weighting 180 +/- 20 g were divided into five groups of six each. Four groups were given sucrose 50% in drinking water for 10 weeks. In 8th week of treatment, three groups of them were randomly selected and treated with Teucrium polium [T. polium] ethyl acetate extract [50, 100 and 200 mg/Kg for two weeks]. Control animals were fed using normal rat chow. After ten weeks, blood samples were collected from the heart. Blood Glucose, insulin, leptin, lipid content and fasting insulin resistance index [FIRI] as well as liver and muscle glycogen and lipid contents were determined. Final data were analyzed by ANOVA and post-hoc Tukey's test. Liver glycogen contents and blood levels of glucose and insulin were significantly increased in high sucrose [HS] group compared with control group. A significant decrease was observed in blood glucose and insulin levels, FIRI, serum total lipid, triglyceride and VLDL-c as well as the liver triglyceride level, muscle and liver glycogen contents in 100 and 200 mg/Kg of TP-treated groups compared with HS group. Leptin level was significantly decreased in 50 and 100 mg/Kg groups compared with HS group. The treatment with T. polium ethyl acetate extract [TP-EAE] induced a dose-dependent reduction in serum, liver and muscle triglyceride [TG] and liver glycogen content levels, as well as serum insulin. These effects may be attributed, in part, to the hypolipidemic effect of TP flavonoids; otherwise, the hepatoprotective and antioxidant activity of TP-EAE may improve the liver function and reverse harmful sucrose effects