Phytochelatin synthesis plays a similar role in shoots of the cadmium hyperaccumulator Sedum alfredii as in non‐resistant plants

Phytochelatin (PC) synthesis is considered necessary for Cd tolerance in non‐resistant plants, but roles for PCs in hyper‐accumulating species are currently unknown. In the present study, the relationship between PC synthesis and Cd accumulation was investigated in the Cd hyperaccumulator Sedum alfredii Hance. PCs were most abundant in leaves followed by stems, but hardly detected by the reversed‐phase high‐performance liquid chromatography (HPLC) in roots. Both PC synthesis and Cd accumulation were time‐dependent and a linear correlation between the two was established with about 1:15 PCs : Cd stoichiometry in leaves. PCs were found in the elution fractions, which were responsible for Cd peaks in the anion exchange chromatograph assay. About 5% of the total Cd was detected in these elution fractions as PCs were found. Most Cd was observed in the cell wall and intercellular space of leaf vascular cells. These results suggest that PCs do not detoxify Cd in roots of S. alfredii. However, like in non‐resistant plants, PCs might act as the major intracellular Cd detoxification mechanism in shoots of S. alfredii.     

Tyrosine kinase syk non-enzymatic inhibitors and potential anti-allergic drug-like compounds discovered by virtual and in vitro screening

In the past decade, the spleen tyrosine kinase (Syk) has shown a high potential for the discovery of new treatments for inflammatory and autoimmune disorders. Pharmacological inhibitors of Syk catalytic site bearing therapeutic potential have been developed, with however limited specificity towards Syk. To address this topic, we opted for the design of drug-like compounds that could impede the interaction of Syk with its cellular partners while maintaining an active kinase protein. To achieve this challenging task, we used the powerful potential of intracellular antibodies for the modulation of cellular functions in vivo, combined to structure-based in silico screening. In our previous studies, we reported the anti-allergic properties of the intracellular antibody G4G11. With the aim of finding functional mimics of G4G11, we developed an Antibody Displacement Assay and we isolated the drug-like compound C-13, with promising in vivo anti-allergic activity. The likely binding cavity of this compound is located at the close vicinity of G4G11 epitope, far away from the catalytic site of Syk. Here we report the virtual screen of a collection of 500,000 molecules against this new cavity, which led to the isolation of 1000 compounds subsequently evaluated for their in vitro inhibitory effects using the Antibody Displacement Assay. Eighty five compounds were selected and evaluated for their ability to inhibit the liberation of allergic mediators from mast cells. Among them, 10 compounds inhibited degranulation with IC₅₀ values ≤10 µM. The most bioactive compounds combine biological activity, significant inhibition of antibody binding and strong affinity for Syk. Moreover, these molecules show a good potential for oral bioavailability and are not kinase catalytic site inhibitors. These bioactive compounds could be used as starting points for the development of new classes of non-enzymatic inhibitors of Syk and for drug discovery endeavour in the field of inflammation related disorders.     

Long‐term ammonium nutrition of Arabidopsis increases the extrachloroplastic NAD(P)H/NAD(P)+ ratio and mitochondrial reactive oxygen species level in leaves but does not impair photosynthetic capacity

Ammonium nutrition has been suggested to be associated with alterations in the oxidation‐reduction state of leaf cells. Herein, we show that ammonium nutrition in Arabidopsis thaliana increases leaf NAD(P)H/NAD(P)⁺ ratio, reactive oxygen species content and accumulation of biomolecules oxidized by free radicals. We used the method of rapid fractionation of protoplasts to analyse which cellular compartments were over‐reduced under ammonium supply and revealed that observed changes in NAD(P)H/NAD(P)⁺ ratio involved only the extrachloroplastic fraction. We also showed that ammonium nutrition changes mitochondrial electron transport chain activity, increasing mitochondrial reactive oxygen species production. Our results indicate that the functional impairment associated with ammonium nutrition is mainly associated with redox reactions outside the chloroplast.     

BIONOMIC OF CAMPOLETIS CHLORIDEAE (HYM:ICHNEUMONIDAE)AS A PARASITOID OF THE COTTON BOLLWORM HELICOVERPA ARMIGERA(LEP:NOCTUIDAE)*

Abstract The bionomics of Campoletis chlorideae and the regularity of its seasonal fluctuations were studied in Changsha district, Hunan province. Field investigation indicated that there were ten generations of C. chlorideae a year, of which seven occurred in cotton fields. Three peaks of cotton bollworm parasitization by C. chlorideae were observed, early May to late June, mid August to early September, mid September to mid October respectively. One peak occurred in tomato and tobacco fields, the other two in cotton fields. The parasitization rate ranged from 25. 1 % ‐63. 1 %. The total development time from egg to adult ranged from 13. O days at 32°C to 75. 5 days at 11. 6 °C. Each wasp could parasitize the 5–23 second instar larvae of tobacco caterpillar. C. chlorideae could parasitize the cotton bollworm, beet armyworm and tobacco caterpillar, but preferred the cotton bollworm larvae. C. chlorideae could parasitized 1st‐ 3rd instar larvae of the tobacco caterpillar, but seldom parasitzed 4th ‐ 6th instar larvae. Moreover, C. chlorideae preferred second instar larvae. Theoretical models for developmental speed, adult longevity and the influence of temperature were proposed. The overwintering of C. chlorideae Uchida was also discussed. Moreover, methods for utilization of C. chlorideae Uchida in crop protection were presented and the bionomics of Curyoletis chlorideae in both the Yangtze River Valley and Yellow River Valley were compared.     

生物医学数据分析中的深度学习方法应用

生物医学数据的积累速度史无前例,为生物医学研究带来机遇的同时,也让传统数据分析技术面临巨大挑战.本文综述了深度学习方法应用在生物医学数据分析中的最新研究进展.首先阐述了深度学习方法,列举深度学习方法的主要实现模型,随后总结了目前生物医学数据分析中的深度学习方法应用情况,分析了在数据处理、模型构建和训练方法等方面共有问题的解决方法,最后给出了深度学习方法应用于生物医学数据分析时可能存在的问题及建议.     

Toll样受体和细胞因子在肠道病毒71型感染的SW620细胞中的表达分析

目的观察肠道病毒71型(EV71)感染人结肠癌SW620细胞中Toll样受体(TLRs)和细胞因子的表达,为EV71感染机制研究提供依据。方法用荧光定量RT-PCR检测EV71感染人结肠癌SW620细胞后24、48和72 h TLR3、TLR7、白细胞介素-6(IL-6)、IL-8、IL-12 mRNA表达量。结果接种EV71后72 h TLR7mRNA表达量增加,TLR3 mRNA表达无变化。IL-6、IL-8和IL-12分别在接种EV71后24、48和72 h开始表达增加,IL-6、IL-8随着时间延长表达量持续增加。结论 TLR7参与介导了抗EV71感染过程,除TLR7外还有其他TLRs参与其中。IL-6、IL-8和IL-12有序地被活化参与抗EV71免疫反应。     

人H5N1流感病毒血凝素蛋白DNA疫苗的构建及其免疫原性研究

将我国分离的首株人H5N1亚型禽流感病毒A/Anhui/1/2005作为研究对象,扩增其HA和HA1基因片段并克隆至真核表达载体pStar,构建成真核表达质粒。通过Western blot和间接免疫荧光检测方法确认,构建的重组质粒在真核细胞中成功地表达了目的蛋白HA和HA1。将重组质粒免疫BALB/c小鼠,检测免疫后外周血中HA/HA1特异性抗体的效价,并比较HA和HA1的免疫原性。结果表明,重组质粒免疫后成功地诱导了体液免疫反应,且二者的血清抗体效价无显著性差异。     

依赖于5′端非编码区高级结构的真核生物mRNA翻译调控

翻译水平的调控是真核基因表达调控的重要环节.近年来的研究表明,许多真核基因的翻译依赖于RNA 5′端非编码区的结构元件.一些小结构元件,如铁离子反应元件,具有1个茎环结构,由铁离子介导控制转铁蛋白的翻译. 核糖开关通过结合特定代谢分子在2种结构状态下切换,调控可变剪接和翻译起始.另1个高度结构化的mRNA元件是内部核糖体进入位点,通过富集核糖体和起始因子促进基因的表达.本文综述了依赖于小结构元件、内部核糖体进入位点和核糖开关的真核基因翻译起始调控相应的研究成果和研究方法.对于研究的前景以及可能存在的挑战也作出阐述.     

生态效益评价内容和评价指标筛选

生态效益评价的重要性已经广为人知,但评价内容和指标不统一,大大影响了评价结果的可信度。基本上是各说各有理,很难相互比较。在分析国内外相关生态系统评价方法基础上,提出生态效益评价框架,强调生态效益与经济效益和社会效益共同构成了人类社会的价值判断标准和决策依据,是经济效益和社会效益的基础,应该包括生态系统整体贡献,考虑与生态系统的动态变化的关系;并探讨了生态效益评价指标筛选的原则(关联性、灵敏性、层级性、决策导向性、代表性、可行性、独立性及经济适用性和社会可接受性);提出了生态效益指标筛选的多准则综合法和生态效益评价指标检验的3个标准(可定量化、专一化和震撼性)。本研究将为生态效益指标体系的构建提供重要参考。