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Objective To construct erythromycin-overproducing mutants by tandemly expressing S-adenosylmethionine synthetase gene metK, Vitreoscilla hemoglobin gene vhbS and pleiotropic regulatory gene adpA in Saccharopolyspora eryth-raea.Methods Through PEG-mediated protoplast transformation , the integrative plasmid carrying metK, vhbS and adpA was respectively introduced into erythromycin-producing wild-type strain S.erythraea A226 and industrial strain WB .The engineered strains were generated by apramycin resistance screening and PCR identification .The erythromycin production was compared in original strains and their mutants by the inhibition test of Bacillus subtilis and HPLC analysis .Results and Conclusion Four A226-derived mutants A226-P1-P4 and three WB-derived mutants WB-P1-P3 were independently obtained.Compared with wild-type strain A226, the relative erythromycin titer of the four engineered strains A 226-P1-P4 was increased from 8%to 25%by scoring the growth-inhibition zones .Further HPLC analysis showed that the four mutants had increased erythromycin A yield by 64%-94%.Likewise, the relative erythromycin titer and erythromycin A yield of the three engineered strains WB-P1-P3 were enhanced by 6%-10%and 31%-62%, respectively, in comparison with the original strain WB.The results show the universality of enhancing erythromycin productionvia tandem expression of metK, vhbS and adpA in S.erythraea.
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Objective: The experiment was designed to study the effects of compound Konjac glucomannan on hyperlipidemia for the purpose of improving the therapeutic efficacy. Method: First, hyperlipidemia rat models were established. Then the effects of compound Konjac glucomannan and Konjac glucomannan on blood lipids levels and hepatic tissue morphous of rats were detected. Result; The compound Konjac glucomannan could decrease LDL-C and ApoB levels of serum TC significantly, while notably increase HDL-C and ApoA-1 levels. The result also shows that compound Konjac glucomannan could obviously improve the TG metabolism and decrease blood glucose concentration. The morphologic observation indicates that both Konjac glucomannan and flavonids could protect liver tissues of rats. Conclusion; Compound Konjac glucomannan could improve regulative ability of lipids metabolism and decrease serum lipids levels.
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Objective: To study the effects of Amorphophallus konjac refined powder combined with minimal flavonids on antioxidation , serum lipids and body weight in rats .Method: Wistar rats were divided into four groups fed with different diets, and then antioxidative ability of blood and liver, levels of serum lipids and body weight were detected and analysed in rats. Results: Konjac refined powder combined with Ginkgo biloba flavonids could decrease MDA content and increase activities of SOD and GSH-Px significantly, and also reduce serum TC, LDL-C, TG levels, improve HDL-C level in rats. As to antiobesity, no notable difference was found .Conclusion: Combined with flavonids, the antioxidation of Konjac food is improved significantly, and serum lipids level is decreased, but antiobesity effect is in-significant.