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Amorpha-4,11-diene synthase (ADS) and Cyt P450 monooxygenase (CYP71AV1) in Artemisia annua L. are two key enzymes involved in the biosynthesis of artemisinin. The promoters of ADS and CYP71AV1 contain E-box elements, which are putative binding sites for basic helix-loop-helix (bHLH) transcription factors. This study successfully isolated a bHLH transcription factor gene from A. annua, designated as AabHLH1, from a cDNA library of the glandular secretory trichomes (GSTs) in which artemisinin is synthesized and sequestered. AabHLH1 encodes a protein of 650 amino acids containing one putative bHLH domain. AabHLH1 and ADS genes were strongly induced by ABA and the fungal elicitor, chitosan. The transient expression analysis of the AabHLH1-green fluorescent protein (GFP) reporter gene revealed that AabHLH1 was targeted to nuclei. Biochemical analysis demonstrated that the AabHLH1 protein was capable of binding to the E-box cis-elements, present in both ADS and CYP71AV1 promoters, and possessed transactivation activity in yeast. In addition, transient co-transformation of AabHLH1 and CYP71AV1Pro::GUS in A. annua leaves showed a significant activation of the expression of the GUS (β-glucuronidase) gene in transformed A. annua, but mutation of the E-boxes resulted in abolition of activation, suggesting that the E-box is important for the CYP71AV1 promoter activity. Furthermore, transient expression of AabHLH1 in A. annua leaves increased transcript levels of the genes involved in artemisinin biosynthesis, such as ADS, CYP71AV1 and HMGR. These results suggest that AabHLH1 can positively regulate the biosynthesis of artemisinin.

BackgroundGastric cancer is a major health problem, and frailty and sarcopenia will affect the postoperative outcomes in older people. However, there is still no systematic review to determine the role of frailty and sarcopenia in predicting postoperative outcomes among older patients with gastric cancer who undergo gastrectomy surgery.MethodsWe searched Embase, Medline through the Ovid interface and PubMed websites to identify potential studies. All the search strategies were run on August 24, 2016. We searched the Google website for unpublished studies on June 1, 2017. The data related to the endpoints of gastrectomy surgery were extracted. Odds ratios (ORs) and their 95% confidence intervals (CIs) were pooled to estimate the association between sarcopenia and adverse postoperative outcomes by using Stata version 11.0. PRISMA guidelines for systematic reviews were followed.ResultsAfter screening 500 records, we identified eight studies, including three prospective cohort studies and five retrospective cohort studies. Only one study described frailty, and the remaining seven studies described sarcopenia. Frailty was statistically significant for predicting hospital mortality (OR 3.96; 95% CI: 1.12–14.09, P = 0.03). Sarcopenia was also associated with postoperative outcomes (pooled OR 3.12; 95% CI: 2.23–4.37). No significant heterogeneity was observed across these pooled studies (Chi2 = 3.10, I2 = 0%, P = 0.685).ConclusionSarcopenia and frailty seem to have significant adverse impacts on the occurrence of postoperative outcomes. Well-designed prospective cohort studies focusing on frailty and quality of life with a sufficient sample are needed.Electronic supplementary materialThe online version of this article (doi:10.1186/s12877-017-0569-2) contains supplementary material, which is available to authorized users.

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