Bacterial community dynamics on bats and the implications for pathogen resistance

The bats skin microbiota plays an important role in reducing pathogen infection, including the deadly fungal pathogen Pseudogymnoascus destructans, the causative agent of white-nose syndrome. However, the dynamic of skin bacterial communities response to environmental perturbations remains poorly described. We characterized skin bacterial community over time and space in Rhinolophus ferrumequinum, a species with high resistance to the infection with P. destructans. We collected environmental covariate data to determine what factors influenced changes in community structure. We observed significant temporal and spatial shifts in the skin bacterial community, which was mainly associated with variation in operational taxonomic units. The skin bacterial community differed by the environmental microbial reservoirs and was most influenced by host body condition, bat roosting temperature and geographic distance between sites, but was not influenced by pathogen infection. Furthermore, the skin microbiota was enriched in particular taxa with antifungal abilities, such as Enterococcus, Burkholderia, Flavobacterium, Pseudomonas, Corynebacterium and Rhodococcus. And specific strains of Pseudomonas, Corynebacterium and Rhodococcus even inhibited P. destructans growth. Our findings provide new insights in characterizing the variation in bacterial communities can inform us about the processes of driving community assembly and predict the host's ability to resist or survive pathogen infection.     

Components of apoptotic pathways modulate HIV-1 latency in Jurkat cells

The ability of the human immunodeficiency virus type 1 (HIV-1) to establish latent infections serves as a major barrier for its cure. This process could occur when its host cells undergo apoptosis, but it is uncertain whether the components of the apoptotic pathways affect viral latency. Using the susceptible Jurkat cell line, we investigated the relationship of apoptosis-associated components with HIV-1 DNA levels using the sensitive real-time PCR assay. Here, we found that the expression of proapoptotic proteins, including Fas ligand (FasL), FADD, and p53, significantly decreased HIV-1 viral DNA in cells. In contrast, the expression of antiapoptotic molecules, such as FLIP, Bcl2, and XIAP, increased the levels of viral DNA. Furthermore, promoting cellular antiapoptotic state via the knockdown of Bax with siRNA and FADD with antisense mRNA or the treatment with the Caspase-3 inhibitor, Z-DEVD, also raised viral DNA. We also simultaneously measured viral RNA from supernatants of these cell cultures and found that HIV-1 latency is inversely proportional to viral replication. Furthermore, we demonstrated that HIV-1-infected cells that underwent the transient expression of FLIP- or XIAP-induced viral latency would then produce an increased level of viral RNA upon the reversal of these antiapoptotic effects via PMA treatment compared to LacZ control cells. Taken together, these data suggest that HIV-1 infection could be adapted to employ or even manipulate the cellular apoptotic pathway to its advantage: when the host cell remains in a pro-apoptotic state, HIV-1 favors active replication, while when the host cell prefers an anti-apoptotic state, the virus establishes viral latency and promotes latent reservoir seeding in a way which would enhance viral replication and cytopathogenesis when the cellular conditions shift to encourage the productive infection phase.     

蜂巢奇露尾甲幼虫龄期的划分

为了明确蜂巢奇露尾甲Aethina tumida Murray幼虫的龄期和最佳分龄指标,本研究分别对不同发育阶段幼虫的头壳宽进行测量,根据各指标的频次分布结果初步确定龄期,并运用Crosby生长法则和线性回归方法进行验证分析。结果表明：蜂巢奇露尾甲幼虫可分为4龄,1~4龄头壳宽度平均值分别为0.1842 mm、0.2942 mm、0.4613 mm、0.7280 mm;此外,本文还对蜂巢奇露尾甲幼虫的形态特征进行描述。本文为研究蜂巢奇露尾甲的发生规律、生物学特性及制定防治措施等提供参考。     

植物幼苗玻璃化发生机制研究进展

玻璃化是指植物生长过程中出现的类似水浸状的半透明化生理病变现象, 常见于植物组织培养。玻璃化现象是限制组培技术发展和组培苗商业化生产的三大主要影响因素之一, 但是玻璃化的发生机制至今尚不清楚。以组培材料为对象研究玻璃化机制受多种人为因素的干扰, 而以非组织培养材料为研究对象, 避免了人为因素的干扰, 有助于从本质上揭示玻璃化发生的分子机制。该文综述了非组培苗因软木脂含量改变、表皮蜡质合成减少、细胞膜过氧化受损、离子或水分子跨膜运输受阻等导致植物玻璃化的机制, 以期为最终揭示植物玻璃化机制提供参考。     

具有外来感染者和急慢性阶段的流行病模型的动力学分析

建立和研究了一类具有外来感染者和急慢性阶段的流行病模型,我们假设单位时间内有常数量的外来感染者进入所研究地区,因而得到的模型仅有一个地方病平衡位置.我们证明了当α＜pμ时,地方病平衡位置是全局渐近稳定的.     

一类具有饱和反应率的脉冲免疫接种的SIS模型

研究了具饱和传染率的脉冲免疫接种SIS模型,得到了无病周期解全局渐近稳定的充分条件和系统持续生存的充分条件．     

JEV-DNA实时荧光定量标准品的构建

利用TaqMan荧光定量PCR技术,建立JEV-DNA定量标准品的制备方法。通过处理JEV减毒活疫苗提取病毒RNA,进行RT-PCR扩增目的片段,与T载体连接,转化感受态细胞,T-A克隆,测序鉴定后定量。获得预期的重组质粒,建立的标准曲线有较大的线性范围。此法制备的重组质粒标准品可用于对病毒载量进行测定。     

外源氨基酸胁迫下植物体内游离氨基酸的测定

目的：通过检测外源氨基酸胁迫下植物体内的游离氨基酸含量,探讨氨基酸胁迫下植物生长受抑制的机制。方法：小麦胚接种在加入D-丙氨酸、D-丝氨酸和L-缬氨酸等3种外源氨基酸的培养基中,其发芽和生长会受到强烈抑制。取材胁迫植株和对照植株,提取并用HPLC方法检测游离氨基酸含量,分析主要氨基酸特征的改变。结果：作为处理的胁迫氨基酸在体内有数倍到数十倍的增高,其他氨基酸,尤其是同族及相近族氨基酸的量也出现较大改变,有增加也有减少,有些氨基酸甚至检测不出。结论：在外源氨基酸胁迫下,植物可直接吸收这些氨基酸,胁迫氨基酸在体内的积累。至少影响到了部分氨基酸的合成,使细胞内正常游离态氨基酸的数量增加或减少,这些变化引起代谢失调,进而引起生长抑制。     

肌细胞分化基因与大鼠肝再生的相关性分析

肌细胞是组织器官的重要组成部分。为在基因转录水平了解肌细胞分化相关基因在大鼠肝再生中的作用,本文用搜集网站资料和查阅相关论文等方法获得上述基因．用Rat Genome2302．0芯片检测它们在大鼠肝再生（liver regeneration,LR）中表达情况,用比较真、假手术基因表达的差异性方法确定肝再生相关基因。初步证实上述基因中52个基因与肝再生相关。根据肝再生中基因表达的时间相关性将上述基因聚合为0．5-1h;2—12h;16、30、42、96h;18—24、36、48—60h;66—72、120-168h等5类,表达上调和下调的基因数分别为8和10,24和8,21和24,53和64,28和36。它们表达的相似性分为均上调、上调占优势、均下调、下调占优势、上调和下调次数相近等5类,涉及15、10、17、7和3个基因,共上调表达143次、下调136次,分为8类表达方式。表明肌细胞分化相关基因表达变化多样和复杂。根据上述结果推测,肝再生中成肌细胞和平滑肌细胞分化增强：骨骼肌和心肌细胞分化相关基因参与肝再生的生理生化活动。     

沉水植物对重金属的吸收净化和受害机理研究进展

沉水植物对重金属的积累净化和受害机理研究主要集中在4个方面: (1)沉水植物对重金属(包括放射性物质)的吸收、积累和净化作用; (2)沉水植物对重金属的抗性强弱和机制; (3)沉水植物用于监测水体的重金属污染; (4)沉水植物的重金属胁迫机制, 包括重金属对植物形态和显微结构的损伤, 对植物抗氧化酶系统的影响, 对植物的叶绿素、蛋白质以及光合与呼吸作用等生理生化指标的影响, 植物对重金属的吸附和转运动力学, 以及Zn对Cd毒害的拮抗等。