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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
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引言 1989年12月,美国FDA批准A型肉毒毒素作为新药投产,以治疗12岁以上人的肌肉紊乱性斜视、偏侧面肌痉挛和眼睑痉挛。还可用于许多其它肌张力障碍和运动失调等疾病的实验性治疗。此举为毒素应用于人的神经和肌肉组织开辟了一个新领域。 相似文献
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产气荚膜梭菌α毒素研究进展 总被引:2,自引:0,他引:2
产气荚膜梭菌是引起各种动物坏死性肠炎,肠毒血症,人类的食物中毒和战创伤性气性坏疽的主要病原菌之一,该菌分为A、B、C、D、E、F6型,其致病因子是菌体产生的外毒素。到目前为止,已发现的外毒素有12种之多,但各型产气荚膜梭菌均产生α毒素(CPA),故以α毒素最为重要。近年来,国外学者对α毒素的组成,结构,作用机制及分子遗传学等方面都作了较为深入的研究,现将有关情况介绍如下。 相似文献
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畜牧业的发展离不开青贮饲料,青贮饲料直接影响着动物的健康以及肉的口感和品质,然而青贮饲料在收获、加工、运输、贮存及饲喂过程中极易受各种霉菌毒素的影响。被污染的青贮饲料会影响反刍动物的生产性能,严重损害动物和人类的健康及畜牧业的发展。如何防止霉菌毒素的产生已成为关键的问题,本文综述了霉菌毒素的概念和种类、霉菌毒素对青贮饲料的不良影响及相应的预防措施,以期为防止霉菌毒素污染青贮饲料和青贮饲料生产提供参考及理论依据。。 相似文献
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Hiroshi Nakajima Kaoru Inoue Tetsuya Ikeda Yukako Fujinaga Hiroyuki Sunagawa Kouichi Takeshi Tohru Ohyama Toshihiro Watanabe Katsuhiro Inoue Keiji Oguma 《Microbiology and immunology》1998,42(9):599-605
The 16S toxin was purified from a Clostridium botulinum type D strain 1873 (D-1873). Furthermore, the entire nucleotide sequences of the genes coding for the 16S toxin were determined. It became clear that the purified D-1873 16S toxin consists of neurotoxin, nontoxic nonhemagglutinin (NTNH), and hemagglutinin (HA), and that HA consists of four subcomponents, HA1, HA2, HA3a, and HA3b, the same as type D strain CB16 (D-CB16) 16S toxin. The nucleotide sequences of the nontoxic components of these two strains were also found to be identical except for several bases. However, the culture supernatant and the purified 16S toxin of D-1873 showed little HA activity, unlike D-CB16, though the fractions successively eluted after the D-1873 16S toxin peak from an SP-Toyopearl 650S column showed a low level of HA activity. The main difference between D-1873 and D-CB16 HA molecules was the mobility of the HA1 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Therefore it was presumed that the loss of HA activity of D-1873 16S toxin might be caused by the differences of processing HA after the translation. 相似文献
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Toru Nishikawa Jun Fujii Shin-ichi Yoshida Takashi Yutsudo 《FEMS microbiology letters》1999,178(1):13-18
Escherichia coli clones expressing recombinant Shiga toxin (Stx)1-A and recombinant Stx1-B subunits, were established. Culture supernatants of these clones were examined for inhibitory activity on in vitro protein synthesis using luciferase as a reporter enzyme. Culture supernatant of the clone expressing Stx1-A, but not Stx1-B, showed the inhibitory activity. Neither recombinant Stx1-A nor Stx1-B showed Vero cell cytotoxicity. For reconstitution of biologically active toxin, the culture supernatants of the Stx1-A clone and the Stx1-B clone were mixed. The reconstituted recombinant Stx1 showed both Vero cell cytotoxicity and inhibition of in vitro protein synthesis. 相似文献
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Genji Sakaguchi Sumiko Sakaguchi Shunji Kozaki Motohide Takahashi 《FEMS microbiology letters》1986,33(1):23-29
Abstract The progenitor toxin of Clostridium botulinum type AB was purified; both large-sized (L) and medium-sized (M) toxins were found. The toxicity of M toxin increased by about 10-fold upon trypsinization; the increase was due mostly to type B toxin and a little to type A toxin. M toxin appeared to consist of one molecule each of toxic and nontoxic components. The activated toxic component was made up of four fragments, A-H- and L-chains and B-H- and L-chains. AB toxin may be a mixture of A and B toxins. 相似文献
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Abstract The quantum yields of intrinsic fluorescence of staphylococcal exfoliative toxins ETA and ETB were determined after excitation at 295 nm and 275 nm respectively. The variations in the intrinsic fluorescence and degree of fluorescence polarization showed conformational modifications of ETA around 57–59°C and of ETB around 52–54°C. Above these transition temperatures, ETB precipitated out and its biological activity was lost, whereas ETA showed almost no precipitation and no change in its biological activity, despite the structural changes in the molecule. 相似文献
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近几年来,关于寄主专化性毒素(Host-Specific Toxin,HST)的作用机制及分子生物学方面的研究有了新进展;在14种寄主专化性毒素中,以Alternaria属的病原菌产生的专化性毒素的研究更为深入。非寄主专化性毒素(Non-Host-Specific Toxin,NHST)的研究着重在毒素产生的条件、生物活性测定、抗性鉴定以及检测被感染植物体的毒素含量等。本文综述了一些能产生专化性毒素和非专化性毒素的植物病原真菌,有链格孢(Alternaria)、镰孢(Fusarium)、尾孢(Cercospora)、轮枝孢(Verticillium)、梨孢(Pyricularia)、疫霉(Phytophthora)、长蠕孢(Helminthosporium)、黑团孢(Periconia)和核盘菌(sclerotinia)等属的病原菌。从所发表的文献表明真菌毒素在植物病害发展中起着重要作用。 相似文献
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Sea anemones are a rich source of two classes of peptide toxins, sodium channel toxins and potassium channel toxins, which
have been or will be useful tools for studying the structure and function of specific ion channels. Most of the known sodium
channel toxins delay channel inactivation by binding to the receptor site 3 and most of the known potassium channel toxins
selectively inhibit Kv1 channels. The following peptide toxins are functionally unique among the known sodium or potassium
channel toxins: APETx2, which inhibits acid-sensing ion channels in sensory neurons; BDS-I and II, which show selectivity
for Kv3.4 channels and APETx1, which inhibits human ether-a-go-go-related gene potassium channels. In addition, structurally novel peptide toxins, such as an epidermal growth factor (EGF)-like
toxin (gigantoxin I), have also been isolated from some sea anemones although their functions remain to be clarified. 相似文献
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Elizabeth W. Davidson 《Journal of invertebrate pathology》1982,39(1):6-9
Soluble cytoplasmic toxin from broken Bacillus sphaericus 1593 sporulating cells was partially purified by ammonium sulfate precipitation, ion exchange, and gel filtration chromatography. Purification was monitored by electrophoresis. The toxin remained active after incubation in the presence of several enzymes and in buffers from pH 6 to 10, but was destroyed by Pronase and subtilisin, and by heating to 80°C for 30 min. Results indicate that the B. sphaericus 1593 cytoplasm contains a single proteinaceous toxin with a molecular weight of 100,000 daltons. 相似文献
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靶向毒素DT-VEGF的构建、表达与活性分析 总被引:2,自引:0,他引:2
肿瘤的快速生长依赖于新生血管的形成。血管内皮生长因子(VEGF)是血管发生和形成过程中的主要介质,其特异性受体在正常组织和肿瘤组织的表达率存在数个数量级的差异,因此可以将毒素分子转运至增生的肿瘤上皮组织中抑制肿瘤血管增生,从而抑制肿瘤的生长。将白喉毒素的前389个氨基酸基因片段与VEGF165通过一短肽相连构建为融合蛋白基因,在大肠杆菌中表达,获得纯化蛋白。实验证实该融合蛋白对血管内皮细胞有特异性杀伤作用,并研究了其对鸡胚尿囊膜新生血管的抑制作用。 相似文献
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《Harmful algae》2013
A model was developed in this paper in order to study and compare the paralytic shellfish toxin (PST) transfer and accumulation of two different potential PST vectors in the planktonic community, the heterotrophic dinoflagellate in its red form Noctiluca scintillans and the copepod Acartia clausi. Different factors that influence the toxin transfer such as toxin synthesis, grazing on toxic and non-toxic food and population size of PST producers and vectors were considered in the model. Moreover, a laboratory experiment was conducted in order to calculate the detoxification rates of Noctiluca fed on Alexandrium catenella. According to the model results, the two grazers showed a significant difference mainly in the timing of the PST accumulation. Noctiluca exhibited a rapid response to the grazing of Alexandrium with high initial toxin accumulation, followed by a reduction to zero concentration of toxins in a period of almost two days. In contrast, Acartia showed a considerable delay in comparison to Noctiluca to accumulate the same amount of toxin in the population. This delay is linked to the slower reproduction rates that characterize the copepod. The range of the initial values used for the sensitivity analysis of the model is representative of the coastal environment of a Galician ria (embayment located at the NW of Iberian Peninsula), where the two grazers and Alexandrium may co-exist. The model for Acartia showed less sensitivity to these key parameters probably due to the time delay in accumulation of significant amount of toxins. Both grazers showed a rapid (50 h) reduction of ingested toxin, suggesting inefficiency to transfer toxins through predation in the food web. 相似文献