Malaria is a global health problem that threatens 300-500 million people and kills more than one million people annually. Artemisinin is highly effective against multidrug-resistant Plasmodium falciparum and it has been widely used as part of the artemisinin-based combination therapies against malaria. To elucidate the biosynthetic pathway of artemisinin and to clone related genes in Artemisia annua, differentially expressed genes between blooming flowers and flower buds were isolated and characterized by a combined approach of suppression subtractive hybridization (SSH) and metabolite analysis. A total of 350 cDNA clones from a subtractive cDNA library were randomly picked, sequenced and analyzed and 253 high-quality sequences were obtained. BLASTX comparisons indicated that about 9.9 % of the clones encoded enzymes involved in isoprenoid (including artemisinin) biosynthesis. The expression of 4 gene transcripts involved in artemisinin biosynthesis was examined by RT-PCR and the results confirmed the higher expression of these transcripts in blooming flowers than in flower buds. In addition, 2 putative transcript factors transparenta testa glabra 1 (TTG1) and ENHANCER OF GLABRA3 (GL3), which promote trichome initiation, were presented in the library. Finally, this study demonstrated that the increase of expression level of the putative TTG1 gene correlated with the improvement of glandular trichome density and artemisinin production in A. annua leaves. The subtractive cDNA library described in the present study provides important candidate genes for future research in order to increase the artemisinin content in A. annua.
Medical thoracoscopy is a commonly used endoscopic technique for the diagnosis and treatment of respiratory diseases. As an invasive technique, it is mainly used for pleural effusions and pleural diseases that cannot be diagnosed by non-invasive methods. It is also of great application in the diagnosis and treatment of certain other diseases. Any technical operation requires special skills. There must be a learning process for mastering these skills. Although internal thoracoscopic surgery is simple, especially for respiratory specialists who have undergone training for thoracentesis or closed drainage, there are discrepancies in thoracoscopic diagnosis and treatment in hospitals in China; furthermore, the surgical methods are not uniform, and some even lead to serious complications. Therefore, the thoracoscopic diagnostic and treatment technology in China needs to be standardized. The Respiratory Professional Committee of the Integrated Medical Branch of the Chinese Medical Doctor Association invited relevant Chinese experts to formulate this standard after several rounds of discussion.
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