硝基咪唑衍生物作为尿素酶抑制剂的分子对接研究

采用AutoDock软件将一系列已有的硝基咪唑衍生物与尿素酶晶体三维结构进行分子对接研究,以便更好地理解该系列抑制剂与尿素酶的结合方式以及酶-底物复合物与作用机理相关的结构与特征。同时,还考察了一组硝基咪唑衍生物抑制活性与分子对接软件预测的结合能之间的相关性,证明分子对接技术是一种可行的尿素酶抑制剂筛选方法。     

Animals as an energy source in third world agriculture

Agricultural development programs have so far been largely unable to meet the food needs of the world's poorest. Increased food production can be achieved only from more intensive agriculture, which requires greater energy inputs per farm worker. Problems of technological infrastructure and escalating oil prices appear to preclude the spread of mechanization to Third World agriculture at this time. Efficient utilization of grazing animals in specific integrated farming systems could not only increase energy inputs through draft and transportation but also increase the yield of high-grade products and by-products from the renewable energy of biomass. An approach to development based on animal agriculture systems is suggested that might initiate a self-sustaining, more productive agriculture requiring only small inputs of fossil-fuel energy.     

Traces of human migrations in Helicobacter pylori populations

Helicobacter pylori, a chronic gastric pathogen of human beings, can be divided into seven populations and subpopulations with distinct geographical distributions. These modern populations derive their gene pools from ancestral populations that arose in Africa, Central Asia, and East Asia. Subsequent spread can be attributed to human migratory fluxes such as the prehistoric colonization of Polynesia and the Americas, the neolithic introduction of farming to Europe, the Bantu expansion within Africa, and the slave trade.     

幽门螺杆菌毒蛋白——空泡毒素研究进展

幽门螺杆菌（Hp）是人体内常见的病原微生物,现发现其与胃癌的发生密切相关。VacA作为Hp感染的一种主要并且重要的毒力因子,推测其在胃癌发生过程中可能起着较为重要的作用。对VacA基因、蛋白的分子结构和研究现状以及VacA诱发细胞毒性的机制做一综述。     

Photolysis of formaldehyde as a hydrogen atom source in the lower atmosphere

The rates of formaldehyde photodecomposition into hydrogen and formyl radicals and hydrogen and carbon monoxide molecules in sunlightirradiated atmospheres have been estimated from extinction data and photochemical results. These data should prove useful in the development of models for the chemical changes that take place in the polluted atmosphere.     

Mussel growth supported by methane as sole carbon and energy source

Symbioses between chemoautotrophic bacteria and several specialized marine invertebrates are well documented. However, none of these symbioses have been demonstrated to provide sufficient energy and carbon to the host to enable it to grow. Growth rates of seep mussels collected from hydrocarbon seeps off the coast of Louisiana were measured in a controlled environment where methane was the sole carbon and energy source. The growth rates increased to a maximum of 17.2 micrometers per day in response to methane and approached zero in the absence of methane. These mussels contain methanotrophic symbiotic bacteria in their gills, which suggests that these bacteria provide their hosts with a net carbon flux originating from methane.     

铋剂四联疗法根除幽门螺杆菌疗效研究

目的比较不同疗程铋剂四联疗法与经典三联疗法根除幽门螺杆菌(Hp)的疗效。方法 选择403 例符合条件的Hp阳性的消化性溃疡或慢性胃炎患者。随机分为三组,其中A 组138 例、B 组142 例、C 组123 例。A组采用果胶铋200 mg+雷贝拉唑10 mg+阿莫西林1 000 mg+呋喃唑酮100 mg,2次/天,共10 d;B组采用果胶铋200 mg+雷贝拉唑10 mg+阿莫西林1 000 mg+呋喃唑酮100 mg,2次/天,共14 d;C组采用雷贝拉唑10 mg+阿莫西林1 000 mg+呋喃唑酮100 mg,2次/天,共14 d。观察三组患者Hp根除率、不良反应发生率及其成本-效果比。结果 A、B、C三组患者Hp根除率分别为83.33%、83.80%、71.54%,A组与B组Hp根除率比较差异无统计学意义(P>0.05),A组与C组、B组与C组Hp根除率比较均差异有统计学意义(P<0.05)。A、B、C三组患者的不良反应发生率分别为 1.45%、2.11%、0.81%,均差异无统计学意义(P>0.05)。A、B、C三组成本-效果比分别为1.50、2.09、2.04。结论 三种治疗方案均未达到Hp根除率>90%的理想方案。但三种方案的比较中含铋剂10 d与14 d四联疗法Hp根除率较高,接近理想方案。含铋剂10 d四联疗法成本-效果比最好,建议临床使用。14 d三联疗法Hp根除率仅达71.54%,远低于理想标准,不建议临床使用。     

Disruption of the epithelial apical-junctional complex by Helicobacter pylori CagA

Helicobacter pylori translocates the protein CagA into gastric epithelial cells and has been linked to peptic ulcer disease and gastric carcinoma. We show that injected CagA associates with the epithelial tight-junction scaffolding protein ZO-1 and the transmembrane protein junctional adhesion molecule, causing an ectopic assembly of tight-junction components at sites of bacterial attachment, and altering the composition and function of the apical-junctional complex. Long-term CagA delivery to polarized epithelia caused a disruption of the epithelial barrier function and dysplastic alterations in epithelial cell morphology. CagA appears to target H. pylori to host cell intercellular junctions and to disrupt junction-mediated functions.     

幽门螺杆菌cagT蛋白的表达、纯化及免疫原性研究

为了解析cagT蛋白的结构,进而了解cagT基因在幽门螺杆菌致病中的作用,应用PCR技术从幽门螺杆菌26695菌株基因组中扩增cagT基因,T/A法克隆,连接至pET-28a(+)栽体,转化宿主细胞E.coli BL21(DE3),IPTG诱导目的蛋白表达,亲和层析法纯化目的蛋白,免疫家兔制备抗体并鉴定其抗原性.成功克隆cagT基因,重组cagT基因片段的测序结果与GenBank上公布的序列相同.重组cagT蛋白以可溶和包涵体两种形式表达,免疫家兔所得的抗体滴度为1:32.结果构建了高效表达cagT蛋白的重组载体pET-28a(+)-cagT,表达的蛋白具有良好的免疫原性,为后续的结构和功能研究奠定了基础.     

Helicobacter pylori SabA adhesin in persistent infection and chronic inflammation

Helicobacter pylori adherence in the human gastric mucosa involves specific bacterial adhesins and cognate host receptors. Here, we identify sialyl-dimeric-Lewis x glycosphingolipid as a receptor for H. pylori and show that H. pylori infection induced formation of sialyl-Lewis x antigens in gastric epithelium in humans and in a Rhesus monkey. The corresponding sialic acid-binding adhesin (SabA) was isolated with the "retagging" method, and the underlying sabA gene (JHP662/HP0725) was identified. The ability of many H. pylori strains to adhere to sialylated glycoconjugates expressed during chronic inflammation might thus contribute to virulence and the extraordinary chronicity of H. pylori infection.     

Left-to-right shunt detection by an intravascular electrode with hydrogen as an indicator

Hydrogen gas crosses the pulmonary membrane and dissolves in blood, and it therefore appears immediately and in high concentration in the left heart and later and in lower concentration in the right heart. The hydrogen-sensing, platinum black-tipped catheter is uniquely sensitive in detecting the left-to-right shunts.     

幽门螺杆菌ureB基因的草莓转化研究

建立了农杆菌介导利用潮霉素抗性作为筛选标记的草莓转化系统。以草莓叶片为材料，把Helicobacterpylori的ureB基因连接到CaMV35S启动子后构成pCAMBIAI3011-ureB表达载体，通过根癌农杆菌EHAl05介导叶盘法转化草莓，经共培养和潮霉素抗性筛选，得到60株抗性植株。对所得植株进行PCR检测，表明阳性苗比例为42％。RT-PCR结果进一步证明目的基因在To代转化植株中已经转录。     

幽门螺杆菌空泡毒素及其单克隆抗体的研究进展

人幽门螺杆菌（H.pylori）是慢性胃炎和消化性溃疡的主要病因，并与胃癌的发生密切相关。幽门螺杆菌的致病机理与其致病性和宿主免疫应答有关，尤以幽门螺杆菌的毒性占主导地位。最新研究表明，约60%的幽门螺杆菌分离株具有分泌空泡毒素（VacA）的能力，并且血清中其相应抗体的出现与消化性溃疡的发生高度平行。综述了VacA的制备和纯化，理化特性，蛋白质结构，编码基因，致病机理及其单克隆抗体等方面的研究进展。     

根除幽门螺杆菌对胃黏膜肠化生的影响

目的：了解幽门螺杆菌(HP)感染伴胃黏膜肠化生者经根除HP后肠化生的变化情况。方法：HP感染伴肠化生者28例口服抗菌药物三联疗法14d，另2l例不予根除HP，6个月后复查胃镜和病理活检。结果：28例中24例HP获根除，肠化生消失或明显减轻者有11／24例，对照组仅有3／2l例，两组差异具有显著性(P＜0．25)。结论：根除HP后肠化生可有效地消除或明显减轻，认为当HP感染伴肠化生时应积极根除HP。     

Ionizing energy as an aid in exchange tritium labeling

The tritium labeling of organic compounds by the Wilzbach technique-that is, by simple exposure of the compound to tritium gas-is greatly accelerated by the simultaneous exposure of the system to a silent electrical discharge. The incorporation of tritium into benzene was increased by a factor of about 10(4) without undue decomposition. Cobalt-60 gamma-rays were found to be far less useful for increasing the tritium incorporation.