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1.
T—2毒素对心肌细胞电生理特性的影响及硒的保护作用 总被引:3,自引:0,他引:3
本实验在培养的Wistar大鼠乳鼠心肌细胞上观察了T-2毒素对膜电位活动的影响及硒的保护作用。结果表明,T-2毒素(0.1,0.5,5.0mg/L)使心肌细胞动作电位幅值(APA)、超射(OS)、阈电位(TP)、最大舒张电位(MDP)及最大除极速率(Vmax)显著降低。使复极化时程(APD10、APD50、APK90)延长;动作电位发放频率(APF)受到明显抑制。提示T-2毒素能抑制Ca^2+、K 相似文献
2.
湖南尖吻蝮蛇毒两个出血毒素的纯化和理化性质 总被引:3,自引:0,他引:3
经SephadexG-75凝胶过滤,QAE-SephadexA-50和CM-Sephadex C-25离子交换层析的步骤,从湖南产尖吻蝮蛇毒中纯化出两个出血毒素。SDS-PAGE测得分子量均为23.5kD,IEF-PAGE测得等电点分别为5.6和5.2,两者具有相似的氨基酸组成,其中酸性氨基酸分别占23%和24%。DaHT-1和DaHT-2的最小出血剂量(MHD)分别为0.5μg和0.8μg。都具 相似文献
3.
从皖南尖吻蝮蛇(Agkistrodonacutus)毒液中经DEAE-Sepharose和SephacrylS-200两步凝胶柱层析首次纯化出一种中分子量出血毒素(简称AaHⅣ).经SDS-PAGE和等电聚焦凝胶电泳测定其分子量为44kD,等电点为pH5.0.从500mg粗毒中可获得20mgAaHⅣ纯品.AaHⅣ有较强的出血活性,最小出血剂量(MHD)为0.4μg. 相似文献
4.
辣椒疫霉产毒共分离RAPD标记的研究 总被引:9,自引:0,他引:9
辣椒疫毒(Phytophthora capsici)毒素的产生是由一个不完全显性基因所控制,通过RAPD/BSA分析证明,用OPW12扩增得到一条约1300bp的RAPD标记带,该带与辣椒疫霉产毒共分离。纯化回收OPW121300DNA,共转化感受态E.coli DH5α,筛选出3个白色阳性克隆,序列分析发现该标记DNA为1291bp。这一标记DNA序列的阐明为进一步分析产毒遗传机理提供了新的信息 相似文献
5.
E型肉毒毒素的分子生物学研究进展 总被引:1,自引:1,他引:0
张雪平 《微生物学免疫学进展》1997,(4)
E型肉毒毒素不同于A型肉毒毒素及具有蛋白分解性的B、F型肉毒毒素,具有自身的特点。本文就E型肉毒毒素的结构、激活及作用机制、E型肉毒毒素的精制特点、基因结构及酪酸梭菌产生E型肉毒毒素的机制探讨等四个方面予以了介绍。 相似文献
6.
皖南尖吻蝮蛇毒出血毒素IV的纯化与初步鉴定 总被引:3,自引:0,他引:3
从皖南尖吻蝮蛇毒液中经DEAE-Sepharose和Sephacryl S-200两步凝胶柱层析首次纯化出一种中分子量血毒素(简称AaHⅣ)。经SDS-PAGE和等电聚焦凝胶电泳测定其分子量为44kD,等电点为pH5.0。从500mg粗毒中可获得20mg AaHⅣ纯品。AaHⅣ有较强的出血活性,最小出血剂量(MHD)为0.4μg。 相似文献
7.
辣椒疫霉(Phytophthora copsici)毒素的产生是由一个不完全显性基因所控制,通过RAPD/BSA分析证明,用OPW12扩增得到一条约1300bp的RAPD标记带,该带与辣椒疫霉产毒共分离。纯化回收OPW12 1300DNA,共转化感受态E.coli DH5a,筛选出3个白色阳性克隆,序列分析发现该标记DNA为1291bp。这一标记DNA序列的阐明为进一分析产毒遗传机理提供了新的信息。 相似文献
8.
辣椒疫霉(Phytophthora copsici)毒素的产生是由一个不完全显性基因所控制,通过RAPD/BSA分析证明,用OPW12扩增得到一条约1300bp的RAPD标记带,该带与辣椒疫霉产毒共分离。纯化回收OPW12 1300DNA,共转化感受态E.coli DH5a,筛选出3个白色阳性克隆,序列分析发现该标记DNA为1291bp。这一标记DNA序列的阐明为进一分析产毒遗传机理提供了新的信息。 相似文献
9.
张雪平 《微生物学免疫学进展》1997,25(4):70-73
E型肉毒毒素不同于A型肉毒毒素及具有蛋白分解性的B,F型肉毒毒素,具有自身的特点。本文就E型肉毒毒素的结构,激活及作用机制,E型肉毒毒素的精制特点,基因结构及酪酸梭菌产生E型肉毒毒素的机制探讨等四个方面予以介绍。 相似文献
10.
经SephadexG-75凝胶过滤,QAE-SephadexA-50和CM-SephadexC-25离子交换层析的步骤,从湖南产尖吻蝮(Dienagkistrodonacutus)蛇毒中纯化出两个出血毒素(DaHT-1和DaHT-2).SDS-PAGE测得分子量均为23.5kD,IEF-PAGE测得等电点分别为5.6和5.2,两者具有相似的氨基酸组成,其中酸性氨基酸(Asx,Glx)分别占23%和24%,DaHT-1和DaHT-2的最小出血剂量(MHD)分别为0.5μg和0.8μg。都具蛋白水解酶活性,无对TAME,BAEE的水解活性和PLA2酶活性.两者的蛋白水解酶活力与出血活性并非正相关.DaHT-1和DaHT-2的最适温度分别为35℃和40℃,最适pH为6-9,对热均不稳定,温度高于60℃活性完全丧失。金属离子的分析显示每摩尔毒素蛋白约含0.5mol的Zn,1mol的Ca,较多的Na、K、Mg,不含Co。 相似文献
11.
Properties and use of botulinum toxin and other microbial neurotoxins in medicine. 总被引:37,自引:0,他引:37
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Crystalline botulinum toxin type A was licensed in December 1989 by the Food and Drug Administration for treatment of certain spasmodic muscle disorders following 10 or more years of experimental treatment on human volunteers. Botulinum toxin exerts its action on a muscle indirectly by blocking the release of the neurotransmitter acetylcholine at the nerve ending, resulting in reduced muscle activity or paralysis. The injection of only nanogram quantities (1 ng = 30 mouse 50% lethal doses [U]) of the toxin into a spastic muscle is required to bring about the desired muscle control. The type A toxin produced in anaerobic culture and purified in crystalline form has a specific toxicity in mice of 3 x 10(7) U/mg. The crystalline toxin is a high-molecular-weight protein of 900,000 Mr and is composed of two molecules of neurotoxin (ca. 150,000 Mr) noncovalently bound to nontoxic proteins that play an important role in the stability of the toxic unit and its effective toxicity. Because the toxin is administered by injection directly into neuromuscular tissue, the methods of culturing and purification are vital. Its chemical, physical, and biological properties as applied to its use in medicine are described. Dilution and drying of the toxin for dispensing causes some detoxification, and the mouse assay is the only means of evaluation for human treatment. Other microbial neurotoxins may have uses in medicine; these include serotypes of botulinum toxins and tetanus toxin. Certain neurotoxins produced by dinoflagellates, including saxitoxin and tetrodotoxin, cause muscle paralysis through their effect on the action potential at the voltage-gated sodium channel. Saxitoxin used with anaesthetics lengthens the effect of the anaesthetic and may enhance the effectiveness of other medical drugs. Combining toxins with drugs could increase their effectiveness in treatment of human disease. 相似文献
12.
Affinity chromatography purification of type A botulinum neurotoxin from crystalline toxic complex. 总被引:6,自引:3,他引:3
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Type A botulinum neurotoxin was purified from toxic crystals by adsorption to p-aminophenyl-beta-D-thiogalactopyranoside coupled to CH-Sepharose 4B. At pH 6.3, the toxic complex was held by the binding between the ligand and the hemagglutinin of the complex; the toxin is eluted selectively by dissociating the complex with buffer-saline of pH 7.9. The single-step affinity chromatography recovered 50 to 60% of applied toxicity as preparations of greater than 99% purity. 相似文献
13.
Enzyme-linked immunosorbent assay for detection of Clostridium botulinum toxin type A. 总被引:11,自引:0,他引:11
The enzyme linked immunosorbent assay using the so-called "double-sandwich technique" has been applied to determine botulinum toxin type A. By this assay, 50-100 mouse ip LD50 of toxin type A can be detected. No cross-reaction occurs with botulinum toxins of other types tested. In all probability this is due to the high specificity of the antiserum prepared against the toxic component of type A toxin. 相似文献
14.
用皂土为载体与类毒素结合方法及破伤风类毒素抗原抗体絮状反应方法去除A、B、C、D、E、F型肉毒抗血清原料中的异型和异种抗毒素(破伤风抗毒素)。制备的A、B、C、D、E、F型肉毒诊断血清每1m l均能中和相应型的肉毒毒素10000LD50以上,而中和异型肉毒毒素或破伤风毒素均低于5 LD50;A、B、C、D、E、F各型混合后的混合型血清每1m l能中和各型肉毒毒素亦大于10000 LD50,中和破伤风毒素低于5 LD50,即效价和特异性符合规程要求。 相似文献
15.
Inhibition by Botulinum Toxin of Acetylcholine Release from Synaptosomes: Latency of Action and the Role of Gangliosides 总被引:2,自引:1,他引:1
S. Wonnacott 《Journal of neurochemistry》1980,34(6):1567-1573
Abstract: Crude and crystalline botulinum toxin type A have been compared for their ability to inhibit [14 C]ACh release from synaptosomes preloaded with [14 C]choline. The toxin preparations exhibited similar dose-response curves, with maximal inhibition at 105 mouse LD50 /ml after 60 min preincubation. The time course for the inhibitory action of the toxin showed that inhibition develops almost linearly over this time period. However, free toxin could be removed from the synaptosome suspension after 15 min without altering the subsequent development of inhibition of [14 C]ACh release, which suggests that the toxin is rapidly fixed by synaptosomes and that fixation alone cannot account for the latency of its action. Incorporation of gangliosides into synaptosomes by prior preincubation failed to increase the potency of the toxin, which implies that gangliosides do not serve as the membrane receptor for the toxin. Treatment of botulinum toxin with dithiothreitol greatly diminished its ability to inhibit [14 C]ACh release and it is suggested that botulinum toxin may be analogous to other bacterial toxins in its structure and mode of action. 相似文献
16.
Monoclonal antibody-based immunoassay for type A Clostridium botulinum toxin is comparable to the mouse bioassay 总被引:3,自引:0,他引:3
C Shone P Wilton-Smith N Appleton P Hambleton N Modi S Gatley J Melling 《Applied and environmental microbiology》1985,50(1):63-67
A monoclonal antibody (BA11) has been produced against Clostridium botulinum type A neurotoxin by the fusion of myeloma cells (P3 NS1/1-Ag4-1) with spleen cells from BALB/c mice immunized with botulinum type A neurotoxoid. The antibody bound specifically to botulinum type A neurotoxin, showing no cross-reactivity with types B and E botulinum toxins or with any of several other bacterial toxins tested. The monoclonal antibody did not bind to botulinum type A neurotoxin which had been denatured with sodium dodecyl sulfate and bound only weakly to each of the separated heavy and light subunits of the neurotoxin, suggesting a conformational requirement for the antigenic determinant of the antibody. A sensitive immunoassay for C. botulinum type A toxin with monoclonal antibody BA11 in conjunction with an enzyme amplication system has been developed which allows detection of 5 to 10 mouse 50% lethal doses ml-1 of purified neurotoxin. The assay was equally sensitive when applied to the detection of crude toxin in food stuffs; the average value for the minimum level of detectable toxin in extracts of tinned salmon or corned beef was 9 +/- 3.1 mouse 50% lethal doses ml-1. 相似文献
17.
Monoclonal antibody-based immunoassay for type A Clostridium botulinum toxin is comparable to the mouse bioassay. 总被引:8,自引:0,他引:8
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C Shone P Wilton-Smith N Appleton P Hambleton N Modi S Gatley J Melling 《Applied microbiology》1985,50(1):63-67
A monoclonal antibody (BA11) has been produced against Clostridium botulinum type A neurotoxin by the fusion of myeloma cells (P3 NS1/1-Ag4-1) with spleen cells from BALB/c mice immunized with botulinum type A neurotoxoid. The antibody bound specifically to botulinum type A neurotoxin, showing no cross-reactivity with types B and E botulinum toxins or with any of several other bacterial toxins tested. The monoclonal antibody did not bind to botulinum type A neurotoxin which had been denatured with sodium dodecyl sulfate and bound only weakly to each of the separated heavy and light subunits of the neurotoxin, suggesting a conformational requirement for the antigenic determinant of the antibody. A sensitive immunoassay for C. botulinum type A toxin with monoclonal antibody BA11 in conjunction with an enzyme amplication system has been developed which allows detection of 5 to 10 mouse 50% lethal doses ml-1 of purified neurotoxin. The assay was equally sensitive when applied to the detection of crude toxin in food stuffs; the average value for the minimum level of detectable toxin in extracts of tinned salmon or corned beef was 9 +/- 3.1 mouse 50% lethal doses ml-1. 相似文献
18.
The enzyme-linked immunosorbent assay using the "double-sandwich" technique was utilized to determine Clostridium botulinum type E toxin. With this technique, about 80 mouse intraperitoneal 50% lethal doses of toxin could be detected. Cross-reaction was hardly observed with C. botulinum type A and B toxins. No cross-reaction was observed with culture supernatants of C. botulinum type C or other Clostridium strains. In all probability this was due to the high specificity of the antiserum prepared aginst the toxic component of type E toxin. 相似文献
19.
Enzyme-linked immunosorbent assay for detection of Clostridium botulinum type E toxin. 总被引:4,自引:2,他引:2
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The enzyme-linked immunosorbent assay using the "double-sandwich" technique was utilized to determine Clostridium botulinum type E toxin. With this technique, about 80 mouse intraperitoneal 50% lethal doses of toxin could be detected. Cross-reaction was hardly observed with C. botulinum type A and B toxins. No cross-reaction was observed with culture supernatants of C. botulinum type C or other Clostridium strains. In all probability this was due to the high specificity of the antiserum prepared aginst the toxic component of type E toxin. 相似文献
20.
We tested the efficacy of a single dose of Botumink toxoid for protecting wild green-winged teal (Anas crecca) during botulism epizootics caused by Clostridium botulinum type C. We challenged control and immunized ducks with four different doses of type C botulinum toxin to determine the LD50 for this species and to evaluate vaccine protection. Fewer immunized ducks were affected with botulism than control ducks, indicating that a single dose of Botumink toxoid could increase the survival of ducks during epizootics. However, the frequency of immunized ducks with signs of botulism increased with the challenge dose of botulinum toxin. Even at doses of botulinum toxin approximately 2 to 4 green-winged teal LD50, about 50% of the immunized ducks were affected. We believe an improved vaccine or a better delivery system is required to justify immunization of wild birds for experimental survival studies. 相似文献