Purification and Characterization of Cytotoxins from Agkistrodon acutus Venom and Their Anticancer Activity

Aim To investigate the anticancer activity of two new cytotoxins from thevenom of Agkistrodon acutus. Methods The venom was isolated by FPLC column chromatography consistingof DEAE Sepharose FF and Source 30S. The cytotoxic activity on tumor cells was detected by MITmethod. Purity and molecular weight were determined by SDS-PAGE (silver staining). Their stabilitiesto temperature and pH were also detected. Results Two pure cytotoxins named ACTX-6 and ACTX-8 wereobtained. Their molecular weights are 98 kDa and 27 kDa, respectively. ACTX-6 consists of twosubunits bonded together by disulfide bonds. Conclusion ACTX-6 and ATCX-8 have highest inhibitoryactivity on lung cancer cell A549. ACTX-6 is stable to heat while ACTX-8 not. ACTX-6 is stablebetween pH 7-9 and ACTX-8 between pH 6 - 9.

Role of Helicobacter pylori virulence factor cytotoxin-associated gene A in gastric mucosa-associated lymphoid tissue lymphoma

Helicobacter pylori(H.pylori)infection might initiate and contribute to the progression of lymphoma from gastric mucosa-associated lymphoid tissue(MALT).Increasing evidence shows that eradication of H.pylori with antibiotic therapy can lead to regression of gastric MALT lymphoma and can result in a 10-year sustained remission.The eradication of H.pylori is the standard care for patients with gastric MALT lymphoma.Cytotoxin-associated gene A(CagA)protein,one of the most extensively studied H.pylori virulence factors,is strongly associated with the gastric MALT lymphoma.CagA possesses polymorphisms according to its C-terminal structure and displays different functions among areas and races.After being translocated into B lymphocytes via typeⅣsecretion system,CagA deregulates intracellular signaling pathways in both tyrosine phosphorylation-dependent and-independent manners and/or some other pathways,and thereby promotes lymphomagenesis.A variety of proteins including p53and protein tyrosine phosphatases-2 are involved in the malignant transformation induced by CagA.Mucosal inflammation is the foundational mechanism underlying the occurrence and development of gastric MALT lymphoma.

Cryptotanshinone inhibits cytotoxin-associated gene A-associated development of gastric cancer and mucosal erosions

BACKGROUND Approximately 90%of new cases of noncardiac gastric cancer(GC)are related to Helicobacter pylori(H.pylori),and cytotoxin-associated gene A(CagA)is one of the main pathogenic factors.Recent studies have shown that the pharmacological effects of cryptotanshinone(CTS)can be used to treat a variety of tumors.However,the effects of CTS on H.pylori,especially CagA+strain-induced gastric mucosal lesions,on the development of GC is unknown.AIM To assess the role of CTS in CagA-induced proliferation and metastasis of GC cells,and determine if CagA+H.pylori strains causes pathological changes in the gastric mucosa of mice.METHODS The effects of CTS on the proliferation of GC cells were assessed using the Cell Counting Kit-8(CCK-8)assay,and the abnormal growth,migration and invasion caused by CagA were detected by CCK-8 and transwell assays.After transfection with pSR-HA-CagA and treatment with CTS,proliferation and metastasis were evaluated by CCK-8 and transwell assays,respectively,and the expression of Src homology 2(SH2)domain–containing phosphatase 2(SHP2)and phosphorylated SHP2(p-SHP2)was detected using western blotting in AGS cells.The enzymelinked immunosorbent assay was used to determine the immunoglobulin G(IgG)level against CagA in patient serum.Mice were divided into four groups and administered H.pylori strains(CagA+or CagA-)and CTS(or PBS)intragastrically,and establishment of the chronic infection model was verified using polymerase chain reaction and sequencing of isolated strains.Hematoxylin and eosin staining was used to assess mucosal erosion in the stomach and toxicity to the liver and kidney.RESULTS CTS inhibited the growth of GC cells in dose-and time-dependent manners.Overexpression of CagA promoted the growth,migration,and invasion of GC cells.Importantly,we demonstrated that CTS significantly inhibited the CagAinduced abnormal proliferation,migration,and invasion of GC cells.Moreover,the expression of p-SHP2 protein in tumor tissue was related to the expression of IgG against CagA in the serum of GC patients.Additionally,CTS suppressed the protein expression levels of both SHP2 and p-SHP2 in GC cells.CTS suppressed CagA+H.pylori strain-induced mucosal erosion in the stomach of mice but had no obvious effects on the CagA-H.pylori strain group.CONCLUSION CTS inhibited CagA-induced proliferation and the epithelial-mesenchymal transition of GC cells in vitro,and CagA+H.pylori strains caused mucosal erosions of the stomach in vivo by decreasing the protein expression of SHP2.

Effect of NaCI and Helicobacter pylori vacuolating cytotoxin on cytokine expression and viability

AIM; To determine whether Helicobacter pylori （H pylon） vacuolating cytotoxin （VacA） regulates release of proinflammatory cytokines （IL-1β, IL-8, TNF-α, and IL-6） or alters gastric epithelial cell viability and to determine whether NaCl affects these VacA-induced changes. METHODS： Vacuolating activity was determined by measuring the uptake of neutral red into vacuoles of VacA-treated human gastric epithelial （AGS） cells. AGS cell viability was assessed by direct cell counting. Specific enzyme-linked immunosorbent assays （ELISA） and reverse transcdptase-polymerase chain reaction（RT-PCR） were performed to examine the effects of H pylori VacA and NaCl on cell pro-inflammatory cytokine production in AGS cells. Immunohistochemical staining of gastric tissue from Mongolian gerbils was used to confirm VacAinduced pro-inflammatory cytokine production and the effects of NaCl on this VacA-induced response. RESULTS： Addition of VacA alone reduced AGS cell viability （P〈 0.05）, and this reduction was enhanced by high doses of NaCl （P〈0.05）. VacA alone induced expression of TNF-α, IL-8 and IL-1β, while NaCl alone induced expression of TNF-α and IL-1β. Changes in mRNA levels in the presence of both VacA and NaCl were more complicated. For the case of TNF-α, expression was dosedependent on NaCl. IL-6 mRNA was not detected. However, low levels of IL-6 were detected by EUSA. Positive immunohistochemical staining of IL-1, IL-6, and TNF-α was found in gastric tissue of H pylori-infected gerbils fed with either a normal diet or a high salt diet. However, the staining of these three cytoldnes was sb＇onger in H pylori-infected animals fed with a 5g/kg NaCl diet. CONCLUSION： VacA decreases the viability of AGS cells, and this effect can be enhanced by NaCl. NaCl also affects the production of pro-inflammatory cytokines in- duced by VacA, suggesting that NaCl plays an important role in Hpylori-induced gastric epithelial cell cytotoxicity.

幽门螺杆菌空泡细胞毒素(Vacuolating cytotoxin,VacA)研究进展

1988年Leunk等发现幽门螺杆菌(Helicobacter pylori,H.pylori)肉汤培养基的上清液含有一种使多种体外培养的真核细胞系发生空泡样变性的毒素,1992年这种毒素得以纯化并被命名为空泡细胞毒素(Vacuo-1ating cytotoxin,VacA).1994年完成了编码VacA的基因vacA的克隆和序列分析,由此VacA作为H.pylori致病的主要毒力因子引起了研究者的广泛兴趣和关注,本文将综述近十年有关VacA的研究进展.

Meta-analysis of the relationship between cytotoxin-associated gene-A and ischemic stroke subtypes

OBJECTIVE： To assess the role of cytotoxin-associated gene-A （CagA） positive strains of Helicobacter pylori （Hp） in ischemic stroke （IS） subtypes. DATA SOURCES： A computer-based online search of PubMed, EMBASE, the Cochrane Collaboration database, the CNKI database and the VIP database, from January 1997 to July 2010, was performed to find relevant studies. DATA SELECTION： Case-control studies relevant to CagA with IS and IS subtypes were selected. Data regarding related factors in the case group and control group were acquired using the same approach. All patients had been diagnosed as exhibiting IS using skull CT or MRI, and were etiologically typed according to the 1993 TOAST diagnosis criteria. Two investigators independently performed the same search and study selection. Meta-analyses were then performed for the selected studies using RevMan 5.0 software （Cochrane Collaboration） after strict screening. Heterogeneity tests, sensitivity analyses and publication bias assessments were then conducted. MAIN OUTCOME MEASURES： Relationship of CagA with IS and IS subtypes. RESULTS： Eight studies were selected, involving data from 879 patients with IS, and 849 healthy controls. Five out of eight of the selected studies were related to large artery atherosclerosis （461 patients with IS and 497 health controls）. The results of our meta-analysis revealed a significant association between prior infection with CagA-positive strains and increased risk of IS （odds ratio （OR） = 2.31,95% confidence interval （C/）： 1.89-2.82, P 〈 0.01）, In addition, we found an association between infection with CagA-negative strains and IS （OR = 0.57, 95%C1：0.47 0.70, P 〈 0.01）. CagA positive and negative strains were found to correlate with large artery atherosclerosis （CagA-positive strains： OR = 2.87, 95%C/： 2.19-3.77, P 〈 0.01; CagA-negative strains： OR = 0.51, 95%CL 0.39 0.67, P 〈 0.01）. Because of the diversity of etiological factors in the case-control study, we conducted further analyses after correcting for confounding factors, and the overall effects were recalculated. The results revealed significant relationships between CagA-positive strains and IS （OR = 2.36, 95%C1： 1.84-3.02, P 〈 0.01）, and between CagA-positive strains and large artery atherosclerosis （OR = 3.10, 95%C1： 2.29-4.19, P 〈 0.01 ）. A heterogeneity test of CagA-positive strains in IS and its subtypes revealed good homogeneity （f = 0%; f = 0%） and we adopted a fixed-effects model to calculate OR. Sensitivity analysis confirmed that the results of the meta-analysis were reliable. However, the funnel plot suggested that the experimental results may be affected by bias, possibly resulting from a lack of published studies reporting negative outcomes in the meta-analysis. CONCLUSION： Infection with CagA-positive strains is a risk factor for IS, especially the large artery atherosclerosis subtype. However, the evidence from case-control studies is weak, and more prospective studies are required to conclusively determine whether infection by CagA-positive strains should be considered a novel risk factor for IS and its subtypes.

幽门螺杆菌诱导上皮-间质转化在胃癌中的作用机制

幽门螺杆菌(Helicobacter pylori,Hp)是一种单极、微需氧、多鞭毛、螺旋形的革兰氏阴性菌,可在人胃黏膜上存活并定植。Hp作为与胃癌相关的Ⅰ类致癌物,其对胃黏膜的长期刺激可导致萎缩性胃炎、消化性溃疡、胃癌和胃黏膜相关淋巴组织淋巴瘤等多种疾病。研究表明,Hp感染可诱导胃上皮细胞发生上皮-间质转化(epithelial-mesenchymal transition,EMT),而EMT的异常调控则会导致胃癌发生。本文就Hp诱导胃上皮细胞发生EMT致胃癌的相关机制研究展开综述,为胃癌的早期诊断和靶向治疗提供新思路。

幽门螺杆菌毒力因子CagA的基因表达调控机制研究进展

全球约有一半人口感染了幽门螺杆菌(Helicobacter pylori,H.pylori),特别是发展中国家的感染率极高。目前,幽门螺杆菌感染已被列为胃癌发生的高危因素。幽门螺杆菌感染的致病机制被认为与环境因素、宿主易感性和细菌毒力等因素之间复杂的相互作用有关。文章主要对幽门螺杆菌毒力因子细胞毒素相关基因(cytotoxin-associated gene A,cagA)表达调控的分子机制进行综述,以便更好地理解cagA的致病性,为今后预防和治疗由幽门螺杆菌所引起的疾病提供理论参考。

幽门螺杆菌东亚型菌株GZ7/cagA^(+)和GZ7/ΔcagA源外膜囊泡的蛋白组学比较

目的通过分离、鉴定和比较细胞毒素相关基因A蛋白(cagA)、阳性幽门螺杆菌(H.pylori)、东亚型菌株GZ7/cagA^(+)及其cagA敲除菌株GZ7/ΔcagA来源的外膜囊泡(OMVs)中的差异表达蛋白(DEPs),分析cagA基因对OMVs中蛋白表达的影响。方法采用超速离心法分别提取GZ7/ΔcagA和GZ7/cagA^(+)的OMVs,通过透射电镜和纳米颗粒追踪技术鉴定其形态和粒径,使用Western blot技术验证两组OMVs中cagA蛋白的表达,分析OMVs的蛋白质组学;对蛋白组学数据进行质控分析和主成分分析鉴定后,以上调蛋白倍数变化(FC)>2.0、下调蛋白FC<0.5,FDR≤0.05为筛选条件筛选DEPs,利用OmicsBean在线工具、Gene Ontology和KOBAS对DEPs进行生物信息学分析;采用免疫荧光鉴定OMVs细胞在细胞中的定位,实时无标记细胞分析仪检测细胞活性。结果通过电镜和粒径证实成功分离纯化了OMVs;蛋白质组分析发现,GZ7/cagA^(+)-OMVs组与GZ7/ΔcagA-OMVs组比较有79个DEPs,其中38个蛋白下调、41个蛋白上调;生物信息学分析显示,DEPs主要与丙酮酸代谢、丙酸代谢、糖酵解/糖异生及柠檬酸循环等代谢途径有关;免疫荧光和实时无标记细胞分析证实H.pylori来源的OMVs能进入细胞并定位在线粒体并抑制细胞增殖。结论cagA能影响H.pylori分泌的OMVs中蛋白质的成分,DEPs可能促进cagA^(+)H.pylori在胃黏膜上的定植及致病性。

血清CagA抗体、G-17、PINP在结直肠癌和腺瘤性息肉中的诊断价值

目的探究血清细胞毒素相关基因A(CagA)抗体、胃泌素-17(G-17)、Ⅰ型前胶原氨基端前肽(PINP)在结直肠癌和腺瘤性息肉中的诊断价值。方法选取保定市第一中医院2022年1月至2023年6月期间收治的77例结直肠癌患者及105例腺瘤性息肉患者作为研究对象,另选取同期在医院体检的83名健康者作为对照组。采用受试者工作特征(ROC)曲线分析血清CagA抗体、G-17和PINP对腺瘤性息肉和结肠癌的诊断价值。结果腺瘤性息肉组和结直肠癌组血清CagA抗体阳性率及G-17表达水平均高于对照组,且结直肠癌组高于腺瘤性息肉组(P<0.05),血清PINP表达水平则与之相反;血清CagA抗体、G-17和PINP表达与息肉直径、结直肠癌分化程度及Dukes分期有关(P<0.05);血清CagA抗体、G-17和PINP单独检测腺瘤性息肉的曲线下面积(AUC)分别为0.547、0.704和0.656,而三者联合检测的AUC为0.829,三者联合检测优于血清CagA抗体、G-17和PINP各自单独检测(Z_(三者联合-CagA抗体)=4.099、Z_(三者联合-G-17)=4.317,Z_(三者联合-PINP)=4.942,P均<0.001);血清CagA抗体、G-17和PINP单独检测结肠癌的AUC分别为0.665、0.659和0.826,而三者联合检测的AUC为0.900,三者联合检测优于血清CagA抗体、G-17和PINP各自单独检测(Z_(三者联合-CagA抗体)=6.196、Z_(三者联合-G-17)=5.988,Z_(三者联合-PINP)=3.992,P均<0.001)。结论血清CagA抗体、G-17和PINP与腺瘤性息肉和结直肠癌的发生及发展密切相关,三者联合检测能够辅助临床诊断腺瘤性息肉和结直肠癌。

海南省39株幽门螺杆菌的耐药性及毒力基因特征

目的了解海南省幽门螺杆菌(Hp)耐药性及其毒力基因vacA、cagA和iceA基因型特征。方法对146例上消化道症状疾病患者进行胃镜检查,取胃黏膜组织进行Hp的分离和培养,对Hp进行药敏检测;通过聚合酶链式反应(PCR)对毒力基因cagA、vacA和iceA进行检测和分型,cagA测序进行聚类分析、并构建系统进化树;使用Fisher确切概率法分析各型毒力基因和患者疾病发生的相关性。结果共培养出39株Hp,对阿莫西林和克拉霉素的耐药率分别为2.6%和48.7%;39株均为vacA^(+)菌株,iceA 1型26株、2型13株;33株为cagA^(+)菌株,其中5株为西方型(EPIYA-ABC型),28株为东亚型(EPIYA-ABD型);cagA^(+)和vacA^(+)菌株与胃和十二指肠疾病有显著的相关性(P<0.05),iceA则无显著性差异(P>0.05)。结论海南省胃和十二指肠Hp患者中Hp毒力基因多样化,vacA s1am2/cagA^(+)基因型在消化性溃疡患者中占优势,不同毒力基因型对胃和十二指肠疾病的发生具有明显的差别,阿莫西林可作为该地区根除Hp首选抗生素。

Cytotoxin-associated gene-A-seropositive virulent strains of Helicobacter pylori and atherosclerotic diseases： a systematic review

Objective A systematic meta-analysis was performed to explore the role of cytotoxin-associated gene-A （CagA） seropositive strains of Helicobacter pylori （H. pylon） in the pathogenesis of atherosclerotic diseases. Data sources Data from Medline, EMBASE, CBMdisc, CNKI and the Cochrane Collaboration database were searched. Similar search strategies were applied to each of these databases. Study selection The review was restricted to the case-control studies on infective, chronic virulent CagA strains of H. pylori, involving the risk of ischemic stroke and coronary heart disease, ineligible studies were excluded. Two reviewers independently extracted the data and assessed study quality. Results Totally 26 case-control studies （11 studies on ischemic stroke and 15 studies on coronary heart disease） were retrieved and considered. The combined data revealed that the chronic seropositive virulent strains of H. pylori infection had a trend of increasing the risk of ischemic strokes and coronary heart diseases, yielding pooled ORs of 2.68 （95% CI： 2.20, 3.27） and 2.11 （95% CI： 1.70, 2.62）, respectively. We also performed subgroup analyses, dividing the total population into Caucasian and Chinese subgroups. Through the subgroup analysis, no significant difference was found between the subgroups. Conclusions Our results support the hypothesis that CagA-seropositive strains infection is significantly associated with susceptibility to ischemic strokes and coronary heart diseases. The magnitude of the association with atherosclerotic diseases needs to be confirmed by prospective studies and the studies on CagA-seropositive strains eradication are more important.

CagA阳性幽门螺杆菌感染与中年无症状人群CIMT相关性研究

目的探讨细胞毒素相关蛋白A(cytotoxin-associated protein A,CagA)阳性Hp感染与中年无症状人群颈动脉粥样硬化(carotid atherosclerosis,CAS)的相关性。方法选取在我院就诊的CAS患者578例作为CAS组,选取无CAS患者578例作为对照组,比较2组CagA阳性Hp感染比例,并作Logistic回归分析。比较CagA阳性Hp感染患者与CagA阴性患者颈动脉内-中膜厚度(carotid intima-media thick-ness,CIMT)。结果CAS组CagA阳性Hp感染患者比例高于对照组(P<0.05)。CagA阳性Hp感染是CAS的独立危险因素(OR=1.813,95%CI:1.379~2.384,P<0.05)。CagA阳性Hp感染患者CIMT大于CagA阴性患者(t=28.046,P<0.05)。结论在中年无症状人群中,CagA阳性Hp感染是CAS的独立危险因素,CagA阳性Hp感染患者CIMT大于CagA阴性Hp感染患者。因此,CagA阳性Hp感染与CAS的发生、发展有关。

眼镜蛇毒细胞毒素-1的分离纯化及其对HSC-LX2细胞PI3K/AKT 信号通路的影响

肝纤维化是多种刺激诱导的肝脏反复损伤的一种病理再生反应[1],其主要表征是肝脏中沉积着过量的细胞外基质(extracellular matrix,ECM)。ECM产生主要原因之一是由于肝星状细胞(hepatic stellate cell,HSC)被大量激活分化,磷脂酰肌醇-3-激酶/蛋白激酶B(PI3K/AKT)信号通路是一条重要的细胞内信号通路,能通过影响HSC的增殖和凋亡来调节肝纤维化[2-4]。

眼镜蛇细胞毒素致昆明小鼠局部皮肤坏死模型的构建

目的通过皮内注射中华眼镜蛇细胞毒素(CTX)建立中华眼镜蛇咬伤皮肤坏死小鼠模型。方法通过凝胶层析+离子层析从中华眼镜蛇粗毒中分离出眼镜蛇细胞毒素(CTX-X)。取30只小鼠随机分为10组:生理盐水组、10μg粗毒组、20μg粗毒组、25μg粗毒组、10μg CTX-X组、20μg CTX-X组、30μg CTX-X组、40μg CTX-X组、50μg CTX-X组、60μg CTX-X组,每组3只。注毒72 h后观察小鼠注射部位皮肤坏死直径及病理变化。结果(1)中华眼镜蛇粗毒通过Sephadex G-50凝胶层析分离获得2个蛋白峰(F1、F2),将CTX-X所在的F2峰经过CM Sepharose TM CL-6B阳离子交换柱色谱分离获得F1、F2、F3、F44个峰,通过小鼠体内实验及SDS-PAGE确定F4峰分离的CTX-X具有活性且达到电泳纯。(2)CTX-X组小鼠的皮内坏死直径随着CTX-X剂量增加而增大,51.21μg CTX-X组的小鼠皮内坏死直径均值达到5 mm。粗毒组小鼠随着皮内注射粗毒剂量的增加,小鼠72 h内的死亡率增高,当皮内注射粗毒剂量<25μg时,注毒72 h后处死并解剖小鼠,注射部位未观察到皮肤坏死情况;当皮内注射粗毒剂量≥25μg时,所有小鼠在注毒后3 h内死亡,且皮内注射部位未见明显坏死。结论应用Sephadex G-50凝胶过滤+CM Sepharose TM CL-6B阳离子交换分离所得的CTX-X,于小鼠背部皮内注射可成功构建中华眼镜蛇CTX-X致局部皮肤坏死的动物模型,该模型稳定性高且具备良好的可复制性。

中华眼镜蛇毒致广西巴马小型猪坏死组织渗出液中的蛇毒成分分析

目的:探究中华眼镜蛇毒致广西巴马小型猪坏死组织渗出液中的蛇毒成分及其蛋白表达的动态变化。方法:给予广西巴马小型猪注射中华眼镜蛇毒,构建蛇伤中毒的局部组织坏死模型,在注射毒素后的6 h、12 h、24 h、36 h和48 h取小猪坏死组织的渗出液,采用无标记的蛋白质组学技术鉴定分析渗出液中蛇毒蛋白质组成及动态变化,通过对所鉴定出的蛋白进行KEGG及GO通路富集分析,以深入了解蛇毒蛋白相关的生物学功能。结果:通过蛇伤中毒后广西巴马小型猪的生物学行为、局部肌肉组织的病理结果、注射部位的伤口变化来评判动物模型,广西巴马小型猪中毒后出现呼吸急促、肌肉组织坏死、局部伤口溃烂等症状,均符合临床特征的实际情况,表明成功构建了中华眼镜蛇毒导致局部组织坏死的广西巴马小型猪模型。在广西巴马小型猪的局部组织坏死渗出液中鉴定到40种蛇毒蛋白质,涵盖三指毒素、磷脂酶A2、富含半胱氨酸分泌蛋白、蛇毒金属蛋白酶、核苷酸焦磷酸/磷酸二酯酶等蛇毒蛋白家族,并呈现出动态性数量变化。结论:在中华眼镜蛇毒致广西巴马小型猪过程中,不同时间段的组织渗出液中均鉴定出多种三指毒素、磷脂酶A2等蛇毒蛋白,其可能在局部组织坏死中发挥着重要作用。

Purification and partial amino acid sequences of a new presynaplic toxin and a cytotoxin from venom of pit veper Agkistrodon blomhoffii brevicaudus

The technique of the reverse-phase performance liquid chromatography (RP-HPLC) was employed to separate and purify the toxic proteins from the venom of Agkistrodon blomhoffii brevicaudus collected in China 3 toxic proteins marked as AgTx-1, AgTx-2 and AgTx-3 consisting of about 122 amino acid residues were screened The toxicities (LD50,) of the AgTx-1, AgTx-2 and AgTx-3 were 0.075, 0.51 and 6.6 mg per kg weight of mice respectively. Toxicological experiment in the chick biventer cervicis nerve-muscle preparation showed that the acetylcholine (Ach) sensitivity of the preparation was unchanged after the total failure of the indirect contraction caused by AgTx-1 and AgTx-2. suggesting that they were presynaptic blockers, namely β-type of snake toxins. However, the amplitude of indirect contraction of the preparation was gradually reduced due to its incomplete relaxation caused by AgTx-3, indicating that it should belong to the category of cytotoxins. The partial amino acid sequences of 3 toxins have been established. It was found in ref. [1] that the sequences of the first 32 N-terminal ammo acid residues of AgTx-1 and AgTx-2, as well as β -agkistrodotoxin (β-AgTx) reported previously were identical (the residue at the position 30 of β-AgTx should be Trp). In view of the similarity in toxicities, and the amounts in the venom and other properties, it was concluded that AgTx-1 should be β-AgTx and consequently was renamed β1-AgTx. AgTx-2 should be the isoform of β1-AgTx, and correspondingly named β2-AgTx.

Impact of Helicobacter pylori virulence markers on clinical outcomes in adult populations

BACKGROUND In recent years,associations between specific virulence markers of Helicobacter pylori(H.pylori)and gastrointestinal disorders have been suggested.AIM To investigate the presence of virulence factors including vacuolating cytotoxin A genotypes(s1m1,s1m2,s2m1,and s2m2),cytotoxin-associated gene A(CagA),and urease activity in H.pylori strains isolated from Arab and Jewish populations in northern Israel and to assess associations between these factors and patients’demographics and clinical outcomes.METHODS Patients(n=108)who underwent gastroscopy at the Baruch Padeh Medical Center,Poriya due to symptomatic gastroduodenal pathologies as part of H.pylori diagnosis were enrolled in the study.Gastric biopsy specimens were collected from the antrum of the stomach.Clinical condition was assessed by clinical pathology tests.Bacteria were isolated on modified BD Helicobacter Agar(BD Diagnostics,Sparks,MD,United States).Bacterial DNA was extracted,and PCR was performed to detect CagA and vacuolating cytotoxin A genes.Urease activity was assessed using a rapid urease test.RESULTS A significant correlation was found between disease severity and patient ethnicity(P=0.002).A significant correlation was found between CagA presence and the s1m1 genotype(P=0.02),which is considered the most virulent genotype.Further,a higher level of urease activity was associated with isolates originating from the Jewish population.Moreover,higher urease activity levels were measured among CagA-/s1m1 and CagA-/s2m2 isolates.CONCLUSION Our study highlights the importance of incorporating molecular methods for detection of virulence markers of H.pylori in order to tailor optimal treatments for each patient.Further investigation should be performed regarding associations between H.pylori virulence factors and ethnicity.

Restoration of Mitochondrial Structure and Function within Helicobacter pylori VacA Intoxicated Cells

The Helicobacter pylori vacuolating cytotoxin (VacA) is an intracellular, mitochondrial-targeting exotoxin that rapidly causes mitochondrial dysfunction and fragmentation. Although VacA targeting of mitochondria has been reported to alter overall cellular metabolism, there is little known about the consequences of extended exposure to the toxin. Here, we describe studies to address this gap in knowledge, which have revealed that mitochondrial dysfunction and fragmentation are followed by a time-dependent recovery of mitochondrial structure, mitochondrial transmembrane potential, and cellular ATP levels. Cells exposed to VacA also initially demonstrated a reduction in oxidative phosphorylation, as well as increase in compensatory aerobic glycolysis. These metabolic alterations were reversed in cells with limited toxin exposure, congruent with the recovery of mitochondrial transmembrane potential and the absence of cytochrome c release from the mitochondria. Taken together, these results are consistent with a model that mitochondrial structure and function are restored in VacA-intoxicated cells.

中华眼镜蛇细胞毒素致小鼠局部皮肤溃疡模型的构建研究

目的:探讨不同部位皮下注射中华眼镜蛇细胞毒素(CTX)致小鼠局部皮肤溃疡模型构建。方法:将57只小鼠随机分为5组:CTX组(n=18)、粗毒组(n=18)、CTX前肢组(n=7)、CTX后肢组(n=7)和CTX背部组(n=7),饲养21天观察皮肤溃疡坏死面积及病理变化。结果:CTX组造模成功率100%,粗毒组造模成功率仅5.5%。选择四肢皮肤注射CTX造模较背部成功率更高,不同注射部位溃疡伤口均可见典型炎症坏死表现。结论:CTX皮下注射小鼠后肢可构建成功率高,稳定,典型的中华眼镜蛇毒素中毒局部皮肤溃疡模型。