Translocation of Helicobacter pylori CagA into gastric epithelial cells by type IV secretion

The Gram-negative bacterium Helicobacter pylori is a causative agent of gastritis and peptic ulcer disease in humans. Strains producing the CagA antigen (cagA(+)) induce strong gastric inflammation and are strongly associated with gastric adenocarcinoma and MALT lymphoma. We show here that such strains translocate the bacterial protein CagA into gastric epithelial cells by a type IV secretion system, encoded by the cag pathogenicity island. CagA is tyrosine-phosphorylated and induces changes in the tyrosine phosphorylation state of distinct cellular proteins. Modulation of host cells by bacterial protein translocation adds a new dimension to the chronic Helicobacter infection with yet unknown consequences.     

卵黄抗体对沙土鼠胃内感染幽门螺杆菌的治疗试验

以蒙古沙土鼠为试验动物,试验鼠间隔48 h 2次灌服接种幽门螺杆菌（Hp）ATCC 43504株布氏培养液1 mL（1.15×10^8cfu.mL^-1）,接种7 d后将试验鼠随机分为4组,每组16只,A、B、C组分别灌服生理盐水、复合抗生素和抗Hp卵黄抗体,每天2次,连续12 d;D组间隔48 h皮下注射抗Hp卵黄抗体2次,探讨Hp特异卵黄抗体对模型鼠胃内Hp感染的治疗效果。结果表明：用药前试验鼠胃内均有大量Hp定植,感染率100%;用药后7 d,B组鼠Hp清除率为60%;但C、D组鼠胃内均有数量较多的Hp存在（P〈0.05）。用药后14 d,B、C、D组胃内Hp清除率分别为60%、60%、40%,三者差异不显著。提示灌服和注射抗Hp卵黄抗体可抑制沙土鼠胃内Hp感染,其抑制效果与抗生素相似。     

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。     

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.     

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。     

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。     

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。     

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.     

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.     

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。     

Natural antibiotic function of a human gastric mucin against Helicobacter pylori infection

Helicobacter pylori infects the stomachs of nearly a half the human population, yet most infected individuals remain asymptomatic, which suggests that there is a host defense against this bacterium. Because H. pylori is rarely found in deeper portions of the gastric mucosa, where O-glycans are expressed that have terminal alpha1,4-linked N-acetylglucosamine, we tested whether these O-glycans might affect H. pylori growth. Here, we report that these O-glycans have antimicrobial activity against H. pylori, inhibiting its biosynthesis of cholesteryl-alpha-D-glucopyranoside, a major cell wall component. Thus, the unique O-glycans in gastric mucin appeared to function as a natural antibiotic, protecting the host from H. pylori infection.     

Disruption of hibernation caused by hypothalamic lesions

Lesions were made in the preoptic-anterior hypothalamic area or ventromedial nucleus of ground squirrels (Citellus tridecemlineatus). Four squirrels, two with preoptic damage and two obese hyperphagics, entered hibernation within 1 to 3 days. They all died after 11 to 12 days, shortly after all normal hibernating squirrels had awakened. Seven squirrels with preoptic damage, rendered hypothermic before being placed in the cold, died within 2 to 6 days.     

幽门螺杆菌尿素酶B亚单位C末端26kDa片段在大肠杆菌中表达及免疫性

构建含幽门螺杆菌(Helicobacter pylori)尿素酶B亚单位3'端720 bp序列表达载体pAMJ399-e,转化大肠杆菌(Escherichia coli)JM109后在低pH下诱导表达.经SDS-PAGE和Western blot分析表明,含pAMJ399-e的E.coli JM109所表达的外源蛋白相对分子量为26 kD,免疫印迹分析证实该重组蛋白可以被幽门螺杆菌阳性患者血清所识别;提纯重组的尿素酶B亚单位C-末端片段(rUreB-E),进行Balb/c小鼠的皮下注射免疫试验,ELISA检测发现,小鼠经rUreB-E免疫后,其血清中均可检测到抗rUreB-E的特异性IgG和IgA抗体,表明rUreB-E具有良好的免疫反应性和免疫原性.     

幽门螺杆菌热休克蛋白基因HspB-C对甘薯遗传转化的研究

甘薯(Ipomoea batatas (L.)Lam.)是世界上重要的粮食、饲料和工业原料作物,作为生物反应器具有优势.幽门螺杆菌被世界卫生组织认定为一类致癌因子,其热休克蛋白(HSP)具有较强的免疫原性,存在着发展为疫苗成分的可能性.本研究构建了幽门螺杆菌热休克蛋白基因HspB-C植物表达载体,以根癌农杆菌(Agrobacterium tumefaciens)介导转入4个甘薯品种诱导愈伤和再分化,通过PCR检测证明目的基因HspB-C已成功转化入甘薯品种南瑞苕中.     

两疗程法清除幽门螺旋杆菌感染对降低十二指肠溃疡远期复发率的效果观察

目的 :观察两疗程法清除幽门螺旋杆菌 (HP)对十二指肠溃疡远期复发率的效果。方法 :将 HP感染合并十二指肠溃疡的 1 1 1例患者随机分为 2组 ;A组 55例 ,用法莫替丁、阿莫西林、甲哨唑、维敏胶囊联合用药 ,疗程 2周 ;B组 56例 ,用药同前 ,半年后重复治疗 2周。完成治疗后 ,分别在 6、1 2、1 8和 2 4月复查胃镜及 HP PCR检测。结果 :A组四个时间段十二指肠溃疡复发率分别为 1 .9%、9.4%、3.8%、3.8% ,2 a总复发率 1 8.9% ;B组为 0 %、1 .8%、1 .8%、1 .8% ,2 a总复发率 5.4%。两组比较 ,B组复发率明显低于 A组 (P<0 .0 5)。结论 :两疗程法清除 HP能明显降低十二指肠溃疡的远期复发率。     

332例幽门螺杆菌感染老年患者多次根除治疗的疗效研究

目的 总结分析幽门螺杆菌(Hp)感染老年患者多次根除Hp治疗后的根除率,探讨反复多次根除Hp治疗疗效及与相关因素的关系.方法 回顾性分析Hp检测阳性的老年病例332例,符合Hp根除治疗的标准,曾多次行抗Hp根除治疗,每次治疗停药1个月后均行13C-尿素呼气试验,有明确随访结果.将收集的病例进行统计学率的计算,多个率的比较采用卡方检验.结果 332例老年患者经第一次抗Hp根除治疗,211例患者13C-尿素呼气试验检测证实Hp为阴性;首次治疗后检测仍为阳性的121例患者,有117例行第二次抗Hp根除治疗,89例患者治疗后行13C-尿素呼气试验证实Hp检测为阴性;检测仍为阳性的28例患者中有16例进行第三次根除治疗,13例患者治疗1个月后行13C-尿素呼气试验检测证实为阴性.结论 对有根除指征的Hp反复阳性老年患者进行及时有效的根除治疗很有必要.反复多次根除治疗时,个体化调整治疗方案,以四联治疗为主,将治疗时间由1周延长为2周,对于提高Hp感染根除率可能有益.     

Disruption of the Dictyostelium myosin heavy chain gene by homologous recombination

The phenomenon of homologous recombination, which allows specific gene conversion and gene insertion, can be a powerful system for the study of eukaryotic cell biology. Data are presented demonstrating that integration of a transfected plasmid by homologous recombination occurs in the motile eukaryotic cell Dictyostelium discoideum. A plasmid carrying a G418 resistance gene and the amino terminal half of the myosin heavy chain gene was used to transfect Dictyostelium. A large fraction of the resultant G418-resistant cells had the plasmid integrated into the single genomic copy of the heavy chain gene. These cells, which fail to express the native myosin but express the myosin fragment, are defective in cytokinesis and become large and multinucleate. In spite of the absence of native myosin, these cells, termed hmm cells, exhibit many forms of cell movement, including membrane ruffling, phagocytosis, and chemotaxis. The hmm cells can aggregate but are blocked at a later stage in the Dictyostelium developmental cycle. The hmm cells revert to the wild-type phenotype. Reversion of the hmm phenotype is due to excision and loss of the transforming plasmid. The revertant cells express native myosin, are G418 sensitive, and have a normal developmental cycle. These results constitute genetic proof that the intact myosin molecule is required for cytokinesis and not for karyokinesis.