霍乱毒素（Cholera Toxins，CTX）
同义名：
Cholera enterotoxin; Choleragen; 霍乱肠毒素；霍乱肠菌素；
搜索关联词：
霍乱毒素（Cholera toxin）； 霍乱类毒素Choleragenoid；霍乱毒素B亚基（CTB）；霍乱毒素B亚单位；腺苷酸环化酶（Adenylate cyclase，AC）；Forskolin 佛司可林；
基本介绍：
霍乱毒素（Cholera toxin，CTX）是霍乱弧菌产生的毒力因子，会引起严重腹泻以及人体脱水。CTX是一种分子量约84kDa的寡蛋白，包含一个A亚基以及包围在周围的5个B亚基构成。CTX是一种有效的腺苷酸环化酶（Adenylate cyclase，AC）活化剂，也是负责霍乱症状的病原物质。霍乱毒素B亚基（a.k.a. 霍乱类毒素choleragenoid）负责全毒素识别并结合到哺乳动物细胞表面的GM1神经节苷脂受体，促进A亚基进入细胞；A亚基承担ADP核糖转移酶（ADP-ribosyl-transferase）活性，此酶能下调Gs蛋白表达并活化AC酶，进而促进cAMP水平提高。A亚基还能ADP核糖基化视杆细胞外节膜盘的转运蛋白，使得GTPase失活。归因于GM1神经节苷脂受体普遍存在于真核细胞膜上，CTX用于各种各样的模型系统中活化腺苷酸环化酶（AC）。CTX还是一种高效的黏膜疫苗佐剂，通过抑制IL-12生产来诱导2型辅助性T细胞的免疫应答。
生理功能：
霍乱毒素（Cholera toxin，CTX）由霍乱弧菌（Vibrio cholerae）代谢纯化所得，不仅在微生物学是一种强大的研究工具，还普遍用于生理学、细胞生物学和生物化学。常见应用如下：
1）因其对腺苷酸环化酶（AC）的效应，CTX通常用来研究信号转导机制。
2）CTX通过刺激B淋巴细胞活性用作一种佐剂；（与疫苗佐剂的开发有关，CTX有效调节哺乳动物细胞免疫系统，用作一种联合抗原共同注射的佐剂）
3）纯化的霍乱毒素B亚基（Cholera toxin B subunit）用于神经研究方面的神经示踪，利用其GM1 神经节苷脂结合和逆行转运特点。
基本参数：
1）CAS NO：9012-63-9
2）纯度：>95%（When examined by polyacrylamide gel electrophoresis in a non-denaturing system run at alkaline pH, this protein migrates as a single major band. When examined on SDS-PAGE, all subunits, A, A1, A2, and B, are present. Densitometric analysis estimates the purity as >95%. The 280 to 260 nm ratio of absorbance (R280/260) is 2.
3）内毒素：~5 EU/mg (determined using a kinetic chromogenic LAL assay)
4）生物活性：Hemagglutination activity is assessed with trisialoganglioside fixed sheep red blood cells using a modification of the method described by Sato, et al. This lot met the specification of exhibiting hemagglutination activity at a toxin dilution ≤1.6µg/ml.
产品信息
List labs提供冻干粉形式的霍乱毒素（Cholera Toxin，CTX，CT）和霍乱毒素B亚基，所有产品经过内毒素去除和无菌处理。并经过严格的纯度和生物活性检测，是高质量的研究工具。部分现货供应，原装进口，欢迎来电咨询。电话：021-54736159，18121428569；QQ:2971634497。
| 品牌 | 产品名称 | 货号 | 规格 |
| List Biological laboratories |
Cholera Toxin from Vibrio cholerae | 101B | 1mg |
| Cholera Toxin (AZIDE-FREE) from Vibrio cholerae | 100B | 1mg | |
| Cholera Toxin B Subunit (Choleragenoid) from Vibrio cholerae | 103B | 1mg | |
| Cholera Toxin B Subunit (Choleragenoid) from Vibrio cholerae in Low Salt | 104 | 0.5mg |
延伸产品：部分现货供应，原装进口，欢迎来电咨询。电话：021-54736159，18121428569；QQ:2971634497。
| 品牌 | 产品名称 | 货号 | 规格 |
| List Biological laboratories |
Cholera Toxin B Subunit (CTB) from Vibrio cholerae FITC, Conjugate | 106 | 0.2mg |
| Cholera Toxin B Subunit Biotin Conjugate | 112 | 0.2mg | |
| Anti-Cholera Toxin B Subunit (Goat) | 703 | 0.1ml |
【应用说明】：
1）霍乱毒素B亚基（CTB）偶联物用于轴浆运输和神经元连接研究中的组织化学标志物（histochemical markers）。
2）Goat Anti-Cholera Toxin B Subunit (Choleragenoid)适用于中和（Neutralization）和结合实验，或与未标记霍乱毒素B亚基联合的免疫组化研究。
引用文献【List Biological】
Wu J et al. Hydrogen postconditioning promotes survival of rat retinal ganglion cells against ischemia/reperfusion injury through the PI3K/Akt pathway. Biochem Biophys Res Commun. 2018 Jan 22;495(4):2462-2468. PubMed ID: 29288664 [Retinal ganglion cells (RGCs)density was counted using haematoxylin and eosin (HE) staining, retrograde labelling with cholera toxin beta (CTB) and TUNEL staining, respectively. List Biological Cholera Toxin B Subunit (CTB) from Vibrio cholerae FITC, Conjugate (#106)]
Aoki S et al. Multizonal Cerebellar Influence Over Sensorimotor Areas of the Rat Cerebral Cortex. Cereb Cortex. 2017 Dec 29. PMID: 29300895 [Under visual guidance, viral solution containing the French subtype of CVS-11 strain of RABV (titrating 4 × 107 plaque-forming units/ml) in conjunction with cholera toxin β-subunit (CTb, low salt; List Biological Laboratories, 1% w/v in 0.2 M phosphate buffer. List Biological Cholera Toxin B Subunit (Choleragenoid) from Vibrio cholerae in Low Salt (#104) ]
Dong L et al. Calcium channels are involved in EphB/ephrinB reverse signaling‑induced apoptosis in a rat chronic ocular hypertension model. Mol Med Rep. 2018 Feb;17(2):2465-2471. PMID: 29207174 [Retinal sections were then blocked for 2 h in 6% normal donkey serum, 1% bovine serum, and 0.2% Triton X-100, and dissolved in PBS at room temperature. Consequently, sections were incubated with the following primary antibodies at 4°C for 24 h: polyclonal rat anti-Cav3.1, anti-Cav3.2, (1:200 dilution; Alomone Labs, Jerusalem, Israel), Goat anti-CTB (cat. no. 703; List Biological Laboratories)]
Konno K et al. Cell-type specific parallel circuits in the bed nucleus of the stria terminalis and the central nucleus of the amygdala of the mouse. J Neurosci. 2014 May 28;34(22):7412-24. PMID: 24872547 [CTb Goat, antiserum 1:3000 choleragenoid Cat. #703, List Biological Laboritories]
Lu X et al. Effects of 1,25 and 24,25 Vitamin D on Corneal Epithelial Proliferation, Migration and Vitamin D Metabolizing and Catabolizing Enzymes. Sci Rep. 2017 Dec 5;7(1):16951.PMID: 29208972 [Each cornea was cut in half and placed in a 35 mm dish with the epithelial side up. After approximately 5 minutes in the laminar air-flow culture hood, the half corneal button attached itself to the bottom of the plate, and 1.5 mL of DMEM with 10% serum containing 40 μg/mL gentamicin, 1% ITS, and100 ng/mLcholera toxin(LIST Biological Laboratories, Inc., Campbell, CA) were added and the tissue was placed in a humidified incubator at 37 °C with 5% CO2. Culture medium was replaced every 2 days.]
Bruxelle JF et al. Clostridium difficile flagellin FliC: Evaluation as adjuvant and use in a mucosal vaccine against Clostridium difficile. PLoS One. 2017 Nov 27;12(11):e0187212. PMID: 29176760 [Vaccination regimen with ovalbumin as antigen: Ovalbumine (OVA) is a commonly used antigen in order to assess adjuvant activity. In two distinct assays, a total of fourteen mice per group received intra-rectally (IR) 20μg of ovalbumin (ovalbumin grade VII, Sigma) with 7μg of adjuvant, either cholera toxin (CT) (List Biological Laboratories, INC)]
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