增溶抽提β－银环蛇毒素结合蛋白及某些突触前毒素对其结合的抑制作用

β－银环蛇神经毒素阻遏神经肌肉接头递质释放的作用机理，可能与它结合于一种突触前的电压依赖的Ｋ~＋通道有关。本文报告了从大鼠膈肌膜组分中用去垢剂ＴｒｉｔｏｎＸ－１００增溶抽提β－银环蛇毒素结合蛋白的结果。这种结合蛋白抽提液的比结合活性为２００－４００ｆｍｏｌ／ｍｇ蛋白，比膜制备物的比结合活力提高约一倍。抽提得率为５０％－７０％。抽提液与^（１２５）Ｉ标记的β－银环蛇毒素的结合可被曼巴蛇神经毒素（ｄｅｎｄｒｏｔｏｘｉｎ）完全抑制，其ＩＣ_（５０）约８×１０^（－８）ｍｏｌ／Ｌ。但另一种β型神经毒素，β－蝮蛇神经毒素（β－ａｇｋｉｓｔｒｏｄｏｔｏｋｉｎ）却完全不能抑制这种结合。这提示，β－蝮蛇毒素与β－银环蛇毒素具有不同的作用位点。

基于酶标噬菌体抗体的磁分离免疫分析方法

以磁微粒偶联多抗为磁性捕获探针,酶标噬菌体抗体为特异信号检测探针,采用＂磁性捕获探针-待测物-酶标噬菌体抗体探针＂的检测模式,成功建立了一种基于酶标噬菌体抗体的磁分离免疫分析方法。本方法检测β-银环蛇毒素线性范围为0.016-62.5μg/L,回归方程为Y=0.641X＋1.355（R=0.9925,n=13,p〈0.0001）,检出限为0.016μg/L。本方法比传统ELISA法检测灵敏度提高了10倍,与采用酶标单抗复合物探针的双抗体夹心磁分离免疫分析法相比,检测灵敏度提高4倍。本方法灵敏度高,具有较好重现性与特异性,在毒素的痕量检测方面具有广阔的应用前景。

功能化超顺磁性Fe3O4纳米微粒的制备及在β-银环蛇毒素检测中的应用

采用微波共沉淀法制备超顺磁性Fe3O4纳米粒子并对其进行功能化修饰，探讨了制备功能化β—BGT磁性纳米微粒的最佳工作条件，建立了双抗体夹心磁分离酶免疫分析法检测β-BGT，结果表明，制备的功能化β—BGT磁性纳米微粒具有良好的活性，每mg磁微粒固定的生物素标记β—BGT多抗最大量为925μg。双抗体夹心磁分离酶免疫分析法检测β-BGT线性范围为0．062～125μg／L，线性回归方程为Y=0．705X＋1．017（R^2=0．991，n=12，P〈0．0001），检测限为O．062μg／L，具有较好的重现性。不同浓度的蓖麻毒素、相思子毒素、葡萄球菌肠毒素B对检测结果基本无干扰。

银环蛇蛇毒毛细管电泳分离与鉴定

采用自制的毛细管电泳装置在 2 4m in内分离并测定了湖南银环蛇蛇毒 ,证明银环蛇蛇毒中含有 α-银环蛇毒素(α-BTX)和 β-银环蛇毒素 (β-BTX) 。

Total synthesis of snake toxin α-bungarotoxin and its analogues by hydrazide-based native chemical ligation

Nicotinic acetylcholine receptors(nAChRs) play important roles in intercellular communications of nerve cells. α-Bungarotoxins(αBtx) is a moderator for the nAChRs. Chemical synthesis provides a promising way to access aBtx and their analogues. Here, we reported a new method for a-bungarotoxin by combining Fmoc-SPPS and peptide hydrazide based ligation strategy. The two-segment ligation method may enable efficient synthesis of aBtx analogues. These synthetic toxin peptides are useful tools for development of imaging or therapeutic reagents.

A genetically engineered neuronal membrane-based nanotoxoid elicits protective immunity against neurotoxins

Given their dangerous effects on the nervous system,neurotoxins represent a significant threat to public health.Various therapeutic approaches,including chelating agents,receptor decoys,and toxin-neutralizing antibodies,have been explored.While prophylactic vaccines are desirable,it is oftentimes difficult to effectively balance their safety and efficacy given the highly dangerous nature of neurotoxins.To address this,we report here on a nanovaccine against neurotoxins that leverages the detoxifying properties of cell membrane-coated nanoparticles.A genetically modified cell line with constitutive overexpression of theα7 nicotinic acetylcholine receptor is developed as a membrane source to generate biomimetic nanoparticles that can effectively and irreversibly bind toα-bungarotoxin,a model neurotoxin.This abrogates the biological activity of the toxin,enabling the resulting nanotoxoid to be safely delivered into the body and processed by the immune system.When co-administered with an immunological adjuvant,a strong humoral response againstα-bungarotoxin is generated that protects vaccinated mice against a lethal dose of the toxin.Overall,this work highlights the potential of using genetic modification strategies to develop nanotoxoid formulations against various biological threats.

Binding properties of β-BuTX binding protein from rat diaphragm muscle

The snake neurotvoxins which selectively block the release of acetylcholine (ACh) from motor nerve terminals, i. e. β-type snake neurotoxins, have been proved to be a very useful tool for analysing the mechanism of transmitter release. Among the β-neurotoxins β-bungarotoxin (β-BuTX) is extensively studied and widely used. β-BuTX with a

重症肌无力患者外周血、骨髓及胸腺的β-BGT结合蛋白抗体分泌细胞的检测

应用ELISPOT方法检测了12例早期发病行胸腺切除术的重症肌无力(MG)患者的外周血、骨髓和胸腺的β-BGT结合蛋白抗体。结果发现,12例MG病人中,骨髓中的阳性率最高。抗体分泌细胞的数量在半数病例中均以骨髓中为最高,各临床类型MG抗体分泌细胞阳性分布不相一致。结果提示骨髓可能为抗体最早产生的部位,抗体分泌细胞的数量及分布与临床类型无关。

Characterization and partial purification of β-BuTX-binding protein from rat diaphragm muscle

β-bungarotoxin (β-BuTX), a basic protein isolated from venom of the snake Bungarusmulticinctus, consists of two polypeptide subunits. As other snake β-neurotoxins, β-BuTXselectively inhibits release of the neurotransmitter, acetylcholine, at the neuromuscular junc-tion. In the central nervous system, however, β-BuTX is cytotoxic for both

β-银环蛇毒素结合蛋白抗体和乙酰胆碱受体抗体亲和性及其在重症肌无力致病中的意义

为了研究β-银环蛇毒素(β-BuTx )结合蛋白在重症肌无力(MG)致病中的作用和意义。我们用牛膈肌乙酰胆碱受体(AChR)和β-BuTx结合蛋白分别免疫Lewis鼠。结果显示AChR免疫鼠能诱导典型的实验性重症肌无力(EAMG)临床症状和血清中高效价的抗AChR抗体。β-BuTx结合蛋白免疫鼠组血清中虽然也能检测到较高效价的β-BuTx结合蛋白抗体,但未观察到明确的EAMG症状。分析和比较了两组免疫鼠血清抗体的亲和指数后发现,β-BuTx结合蛋白抗体亲和指数明显低于AChR抗体亲和指数。我们认为:β-BuTx结合蛋白在实验动物中具有抗原性,但它的抗体亲和性远较AChR为低,这可能是β-BuTx结合蛋白缺乏致Lewis鼠肌无力的重要因素之一。

用β-银环蛇毒素结合蛋白免疫小鼠复制的具突触前变化的重症肌无力动物模型

20只雄性BALB/c小鼠,随机分成实验组和对照组.每只实验组小鼠每次注射溶于1.3ml完全福氏佐剂中的20μg从小牛膈肌纯化的β-银环蛇毒素结合蛋白,而每只对照组小鼠则只注射同容积上述佐剂。每周注射1次,共4次。第2次注射后,实验组小鼠行为上出现了全身少动现象。于第4次注射后约1周逐次杀死小鼠,制备膈神经-膈肌标本,进行电生理学实验。结果表明,在实验组小鼠标本记录的终板电位的量子含量显著减少(P<0.05)和由高K^+浓度(17.5mol/L)的Krebs溶液引起的小终板电位频率升高反应非常显著地降低(P<0.01)。这些变化与以前用被动免疫方法得到的结果是一致的。