Effects of ecological environment and host genotype on the phyllosphere bacterial communities of cigar tobacco (Nicotiana tabacum L.)

Microorganisms of plant phyllosphere play an important role in plant health and productivity and are influenced by abiotic and biotic factors. In this study, we investigated the phyllosphere bacterial communities of three cigar tobacco varieties cultivated in Guangcun (GC) and Wuzhishan (WZS), Hainan, China. Metagenomic DNA was extracted from tobacco leaf samples and sequenced by 16S rDNA amplicon sequencing. Our results showed that bacterial communities of cigar tobacco phyllosphere in GC exhibited remarkably higher alpha diversity than that in WZS. There was slight effect of tobacco genotype variations on the alpha diversity in both cultivation sites, and beta diversity and structure of bacterial community were not influenced significantly by the cultivation sites and tobacco varieties. Statistical analyses of species diversity unraveled that the dominant species in bacterial communities of cigar tobacco phyllosphere among all these samples were phylogenetically affiliated to Proteobacteria and Cyanobacteria. At the genus level, the most abundant microorganism was Limnobacter, followed by Brevundimonas, unidentified_Cyanobacteria, and Pseudomonas. Additionally, environmental conditions except for humidity were negatively correlated with the relative abundance of bacterial genera. Further analyses revealed that influence of site‐specific factors on tobacco bacterial community was relatively higher than genotype‐specific factors. In short, this study may contribute to the knowledge base of practical applications of bacterial inoculants for tobacco leaf production.     

Conformational rearrangements to the intracellular open states of the LeuT and ApcT transporters are modulated by common mechanisms

Recent crystallographic studies revealed that five transporter families without much sequence similarities among them have similar structure folds to LeuT, a bacterial neurotransmitter:sodium symporter homolog. The LeuT fold is characterized by an internal twofold structural pseudosymmetry. The transport cycle of some members of each of these families is dependent on a sodium gradient across the membrane, whereas in some others the role of sodium is mimicked by proton. We report on the identification of common structure-dynamics elements of the transporters with LeuT fold, which are recognizable in the conformational transitions related to function. The findings from comparative computational modeling and simulation studies of LeuT, and ApcT from the amino acid-polyamine-organocation transporter family define the intramolecular mechanisms by which Na⁺ binding couples to the transport process, and single out the lead/active role of TM1a in the transition to inward-open conformation. These mechanistic insights are derived in the context of collaborative investigations of LeuT dynamics with both single-molecule fluorescence and simulations that have produced excellent agreement of the dynamic details, and are found to be generalizable across the transporter families and to transcend sequence and motif similarities.     

4490例创伤伤员致伤原因分析

目的:探讨创伤伤员的致伤原因,为院前急救和预检分诊提供依据,为提出预防创伤发生的策略和措施奠定基础。方法:对4490例创伤伤员的资料进行统计分析,分析不同性别、年龄和地区创伤伤员的致伤原因的异同。结果:4490例创伤伤员中中,男女比例为2.81:1。年龄特点:12～60岁组发生创伤达75.16%。6岁以下以烧伤为主要原因,占41.08%;大于60岁以上以跌落/摔伤为主要原因,占63.79%;骨折多发生于12～60岁。致伤原因:跌落/摔伤(占28.69%)、道路交通伤(占28.53%)、锐器/切割伤(占13.23%)。结论:创伤伤员的致伤原因在不同性别、年龄和地区间有着明显特点,可根据具体情况采取相应的防范措施,以减少其发生,同时为创伤伤员的院前急救和预检分诊提供依据。     

循环肿瘤细胞在乳腺癌预后评价中的应用和意义

循环肿瘤细胞(CTCs)是导致肿瘤转移的主要原因,它在外周血中的含量与乳腺癌的转移、治疗和预后有密切的关系.本文对于CTCs的概念、检测方法、以及作为肿瘤转移预测指标的优势进行了综述.并对其在临床上的运用前景进行了展望.     

组织学与胚胎学教学模式的改革

医学教育任重而道远,培养优秀的医学生,要从基础抓起.组织学与胚胎学是医学教育中的基础学科,是学习其它医学理论知识的基石.但是,相对于其它学科,组织学与胚胎学的学习枯燥,难懂,难记忆.因此,如何创新组织胚胎学的教学模式,激活课堂气氛,提高学生学习的热情和兴趣,引导学生找到发现问题、解决问题的方法是组织学与胚胎学教学中急需解决的重要问题.     

社区居民对基因检测服务需求意愿及其影响因素调查分析

目的:了解社区居民对基因检测服务的知晓、需求状况及需求意愿的影响因素。方法:采用典型抽样方法,对杭州市下城区1647户居民进行问卷调查。结果:调查人群对基因检测知晓率为21.8%,需求率为12.7%,有需求意愿的占到61.9%。有无家庭成员患病(OR=1.619,95%CI=1.279-2.049)、对基因检测服务知晓情况(OR=2.368,95%CI=1.782-3.146)、有无家族遗传史(OR=2.784,95%CI=1.685-4.600)年龄(x2=27.210,P<0.001)、对婚前基因检测的认可度(x2=23.185,P<0.001)等五个因素对社区居民基因检测服务需求意愿有显著影响。结论:社区居民对基因检测服务需求意愿较强,但是知晓率、需求率均偏低。有待加强相关方面的宣传、教育、培训等工作。     

慢病毒靶向携带Survivin siRNA抗肺腺癌的体内研究

目的:探讨慢病毒载体介导的靶向survivin基因小干涉RNA(survivin-siRNA)对裸鼠移植人肺腺癌的体内抑瘤活性。方法:构建表达survivin-siRNA的慢病毒载体和移植人肺腺癌裸鼠模型,肿瘤组织局部注射survivin-siRNA慢病毒载体,观察肿瘤体积及随时间生长变化;PI染色检测细胞凋亡;流式细胞术检测肿瘤细胞周期变化。结果:慢病毒载体介导survivin-siRNA对裸鼠肺腺癌的抑瘤率为46.07%;30～35%的肿瘤细胞凋亡;G1期细胞比例明显增加,S期细胞比例则明显减少。结论:靶向survivin的RNAi能有效抑制裸鼠移植人肺腺癌的生长,诱导肿瘤细胞凋亡和细胞周期改变。     

硫酸长春碱聚乳酸缓释纳米粒的制剂学研究和体外释放度考察

目的:制备硫酸长春碱聚乳酸纳米粒(VLB-PLA-NPs)并考察其体外释放度.方法:采用复乳挥发法制备VLB-PLA-NPs,以包封率为主要指标评价指标,选择聚乳酸用量、超声时间、外水相浓度为考察因素,优化制备工艺,考察体外释放度.结果:优化工艺制备得VLB-PLA-NPs平均粒径为65±3.03nm,包封率为(99.68±0.30)%,载药量为3.323±0.01μg/mg,体外释放可持续20天.结论:该制备工艺操作简便,结果稳定,缓释特征明显,应用前景良好.     

小剂量α-干扰素联合利巴韦林治疗丙型肝炎肝硬化脾功能亢进的疗效与安全性

目的:观察应用α-干扰素(IFN-α小剂量开始逐渐加量联合利巴韦林治疗丙型肝炎肝硬化代偿期脾功亢进的临床疗效及安全性.方法:14例丙型肝炎肝硬化脾功亢进患者采用IFN-α利巴韦林治疗.IFN-α1MU,隔日一次,皮下注射,两周后对耐受良好的患者,将IFN-α量增加至2MU,以后如能够耐受,则每4周增加1MU,直至5MU,如不能耐受增加剂量,则按原剂量治疗,疗程一年.利巴韦林开始剂量600mg/d,如能耐受逐渐增加至900～1200mg/d,不能耐受按原剂量治疗,疗程一年.观察基因型、血常规、肝功能、HCV-RNA及不良.结果:14例患者,8例为基因1b型;6例为基因2a型.12例患者完成一年疗程.8例出现病毒学应答,应答率66.7%,HCV-RNA平均下降3.6±1.7log10,SVR33.3%,肝功能复常率75%,白细胞、血小板治疗前后比较差异无统计学意义.无不良事件发生.1例合并特发性血小板减少性紫癜(ITP)患者白细胞、血小板恢复正常,PAIg-G明显下降.结论:丙型肝炎肝硬化脾功能亢进患者可选择小剂量IFN-α合利巴韦林逐渐加量治疗方案治疗,未见明显不良反应.