| Hypercholesterolemia is a major risk factor for the development and progression of cardiovascular diseases including atherosclerosis, which is related with dysfunction of the vascular endothelial cells. Scutellarin is a major active ingredient from the plant Erigeron breviscapus. It is widely used for curing cerebral ischemia and other sequelaes caused by cerebrovascular accident in clinic.Before this study, we predict the proper environments for Erigeron breviscapus, to find more producing areas for Erigeron breviscapus.The aim of this study is to see whether scutellarin could adjust the abnormal lipid levels, delay the progress of atherosclerosis and maintain the normal function of thoracic aorta on the diet-induced hypercholesterolemia rats.Animals of experimental groups are fed with a standard rat chow supplemented with 1%cholic acid,2%pure cholesterol and 5.5%oil to form hypercholesterolemia. Scutellarin is given by intragastric administration for 30,100 and 300 mg/kg/day. The lipid profile and oxidation resistance are monitored, and aortic functions in Sprague-Dawley rats are tested, including vasorelaxation, in vitro NO production, serum nitric oxide synthase and eNOS mRNA expression. The results indicate that:(1) scutellarin can markedly attenuate the increased serum and liver total cholesterol induced by atherogenic diet, reduce the rised liver triglycerides, renew the high density lipoprotein cholesterol and alleviate hypercholesterolemia’s symptoms. Its vascular protection may carry out by improving the lipid metabolism in the hypercholesterolemia rats, interrupting lipid aggrading and retarding dysfunction of vascular endothelial cells.(2) scutellarin can ameliorate vascular endothelial cells’function and improve acetylcholine-induced endothelium-dependent vasorelaxation in hypercholesterolemia rats’isolated thoracic aortas.(3) scutellarin administration can significantly enhance acetylcholine-induced NO production and increase the gene expression of endothelial nitric oxide synthase.(4) scutellarin has the mightiness power of clarity the free radical of DPPH. It can also improve the activity of GSH-Px and reduce the amount of MDA in both serum and liver. Chloroplast (cp) genome is the total circular DNA in the chloroplast. Because of its high conservation and maternal inheritance, cp genome can be used in phylogenetic analysis, genetic engineering, identification of plants and other fields as well. At present, there are only 213 complete cp genomes in publication. The lack of cp genome information may severely hamper the further progress of plant and cp genome studies.This dissertation bases on early studies, having optimized a simple, rapid and effective method for cp DNA extraction. Using 454 Genome Sequencer FLX System and multiplex identifier (MID) parallel sequencing method, we obtain the complete cp genomes of taxus (Taxus chinensis var. mairei (Lemee et Levl.) Cheng et L. K. Fu) and cycad (Cycas revoluta Thunb.) through de novo and reference guided assembly.After validation and annotation, we present the complete cp genome of taxus, which is 127,663 bp in length. Compared to other land plant genomes, this cp genome has lost one of the large IR regions. So we are unable to define the large and small single copy regions in this genome. The GC content of this genome is 34.72%, which is the lowest GC content among the already existing gymnosperms. It contains 109 single copy genes and two duplicated (trnl-CAU and trnQ-UUG) genes that give a total of 113 genes. There are 4 rRNA genes and 29 tRNA genes in taxus. Twelve of all the genes include one or more introns. Three of them are tRNA genes while the left 9 are protein coding genes. Taxus contains 199 homopolymers (7≥bp) and 411 repeat sequences (≥30 bp). It has the most repeat sequences in the known gymnosperms.Cycad is 162,494 bp in length, which include a pair of IRs of 25,066 bp separated by a small single copy region of 23.379 bp and a large single copy region of 88.983 bp. Its GC content is 39.38%. It is the second highest GC content among the existing gymnosperms, just lower than Cycas taitungensis C. F.. another kind of cycad. Cycad contains 142 unique genes and 22 duplicated genes that give a total of 164 genes. Thirty eight of them are tRNA genes and 8 are rRNA genes. Twenty two genes contain two or more exons,8 of them are tRNA genes and the left 14 are protein coding genes. Cycad contains 141 homopolymers (≥7 bp) and 68 repeat sequences (≥30 bp). Its repeat sequences are far less than Cycas taitungensis.We also perform a simple phylogenetic analysis in the existing 20 gymnosperms through maximum parsimony (MP) and maximum likelihood (ML) analysis using tobacco and horse-tail as outgroups. Both MP and ML trees indicate that taxus is close to Cryptomeriajaponica (Linn, f.) D. Don while cycad is sister to Cycas taitungensis C.F. |
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