三氮唑类衍生物的合成及其对幽门螺杆菌体外抑制活性研究

设计并合成了15个未曾见文献报道的1-(2-(4-取代)苯氧乙基)-1H-1,2,3-三氮唑衍生物,并通过NMR、IR、MS确认了它们的结构.幽门螺旋杆菌(HP)体外抑制活性测试结果表明,4个化合物对16株HP表现出一定的抑制活性.     

幽门螺杆菌HpaA蛋白单克隆抗体的制备及其初步应用

目的 制备幽门螺杆菌(H.pylori)HpaA蛋白单克隆抗体,并检测其对H.pylori黏附胃腺癌细胞AGS的抑制作用。方法应用PCR法扩增HpaA基因,构建重组表达质粒pQE30-HpaA,表达并纯化重组HpaA蛋白;以其为抗原免疫BALB/c小鼠,将小鼠脾细胞与骨髓瘤细胞SP2/0融合,筛选阳性杂交瘤细胞株,采用间接ELISA和Western blot法检测单抗的特异性,间接ELISA检测细胞株培养上清和腹水抗体效价,并对其进行亚型鉴定和杂交瘤细胞株稳定性分析;扫描电镜观察重组HpaA蛋白单抗对H.pylori黏附AGS细胞的抑制作用。结果重组表达质粒pQE30-HpaA经双酶切、PCR及测序证明构建正确;表达的重组HpaA蛋白相对分子质量约为30 000,可溶性蛋白含量约占65%,纯化后纯度达85%以上;经细胞融合及筛选克隆获得了2株能稳定分泌抗HpaA单抗的杂交瘤细胞株,2株单抗与其他肠道细菌均无交叉反应,能与H.pylori全菌体发生特异性反应;乳胶凝集试验证明,该单抗属IgG3、κ型;2株单抗细胞培养液的抗体效价分别为1∶128～1∶256和1∶64～1∶128,腹水抗体效价分别可达1∶6 400～1∶12 800和1∶1 600～1∶3 200;杂交瘤细胞经反复冻存、复苏及多次传代,仍能稳定分泌高效价抗体;单抗可抑制H.pylori对AGS细胞的黏附作用。结论已成功制备了H.pylori HpaA蛋白单克隆抗体,为建立新的H.pylori现症感染诊疗方法奠定了基础。     

幽门螺杆菌热休克蛋白A亚单位基因工程菌的发酵

目的 研究幽门螺杆菌热休克蛋白Ａ亚单位（ＨｓｐＡ）基因工程菌的发酵工艺。方法 通过不同培 养基、不同葡萄糖浓度、不同溶氧条件、补料与非补料对幽门螺杆菌热休克蛋白Ａ亚单位基因工程菌的菌体生长与 外源蛋白表达量的影响的比较,确定其较为合适的培养条件。结果 多批实验证明,菌体单产可达４２ｇ／Ｌ,目的蛋 白的表达率为３８．５％。结论 此发酵工艺可以提高ＨｓｐＡ基因工程菌菌体的得率和目的蛋白的表达。     

Synthesis and Biological Evaluation of Dithiobisacetamides as Novel Urease Inhibitors

Thirty-eight disulfides containing N-arylacetamide were designed and synthesized in an effort to develop novel urease inhibitors. Biological evaluation revealed that some of the synthetic compounds exhibited strong inhibitory potency against both cell-free urease and urease in intact cell with low cytotoxicity to mammalian cells even at concentration up to 250 μM. Of note, 2,2′-dithiobis(N-(2-fluorophenyl)acetamide) ( d7 ), 2,2′-dithiobis(N-(3,5-difluorophenyl)acetamide) ( d24 ), and 2,2′-dithiobis(N-(3-fluorophenyl)acetamide) ( d8 ) were here identified as the most active inhibitors with IC₅₀ of 0.074, 0.44, and 0.81 μM, showing 32- to 355-fold higher potency than the positive control acetohydroxamic acid. These disulfides were confirmed to bind urease without covalent modification of the cysteine residue and to inhibit urease reversibly with a mixed inhibition mechanism. They also showed very good anti-Helicobacter pylori activities with d8 showing a comparable potency to the clinical used drug amoxicillin. The impressive in vitro biological profile indicated their immense potential as therapeutic agents to tackle H. pylori caused infections.     

新型抗螺旋菌剂——2—（芳烷基）胍—4—呋喃噻唑

胃溃疡疾病是由于幽门螺旋菌所致。药理研究表明 ,2 -(芳烷基)胍 -4 -呋喃噻唑类化合物具有较强的抗菌、抗组胺和抗胃酸分泌作用。     

幽门螺杆菌VacA毒素诱导凋亡

研究了天然VacA细胞空泡毒素蛋白诱导细胞空泡和凋亡的生物学活性.培养空泡毒素阳性的Hp菌株,超声碎菌后提取上清,用SDS—PAGE分析上清中目的条带,测定其蛋白含量,用电镜观察VacA致Hela细胞空泡样变,然后用MTT法检测Hela细胞的生长曲线后,分别用MTT法分析VacA对Hela细胞的生长抑制作用,以及用TUNEL法和流式细胞技术检测VacA蛋白致凋亡的细胞毒活性.实验结果表明,在PAGE上可见相应VacA蛋白条带,电镜下天然VacA毒素致Hela细胞空泡化明显,因此VacA毒素可以抑制Hela细胞的生长,并且诱导其凋亡;在倒置显微镜下观察可见细胞空泡、脱落,胞浆浓缩,胞核皱缩、碎裂,呈现圆形固缩状态.MTT法数据示H.pylori Va-cA蛋白具有浓度依赖性地致细胞毒活性,光镜下可见TUNEL法中可显示棕黄色凋亡细胞,因此证明幽门螺杆菌VacA蛋白有明显的诱导Hela细胞凋亡的作用.     

Understanding the Key Factors that Control the Inhibition of Type II Dehydroquinase by (2R)‐2‐Benzyl‐3‐dehydroquinic Acids

The binding mode of several substrate analogues, (2R)‐2‐benzyl‐3‐dehydroquinic acids 4 , which are potent reversible competitive inhibitors of type II dehydroquinase (DHQ2), the third enzyme of the shikimic acid pathway, has been investigated by structural and computational studies. The crystal structures of Mycobacterium tuberculosis and Helicobacter pylori DHQ2 in complex with one of the most potent inhibitor, p‐methoxybenzyl derivative 4 a , have been solved at 2.40 Å and 2.75 Å, respectively. This has allowed the resolution of the M. tuberculosis DHQ2 loop containing residues 20–25 for the first time. These structures show the key interactions of the aromatic ring in the active site of both enzymes and additionally reveal an important change in the conformation and flexibility of the loop that closes over substrate binding. The loop conformation and the binding mode of compounds 4 b – d has been also studied by molecular dynamics simulations, which suggest that the benzyl group of inhibitors 4 prevent appropriate orientation of the catalytic tyrosine of the loop for proton abstraction and disrupts its basicity.     

茅台酒与幽门螺旋杆菌

通过一些实际例子,证明茅台酒具有治疗胃病的功效。结合幽门螺旋杆菌的基本研究状况及其与胃病间的关系,推断茅台酒对幽门螺旋杆菌具有杀灭或抑制其生长繁殖的作用;指出此方面的相关研究需从茅台酒健康成分及其对人体内环境产生变化等方面开展。（晓文）