Division of Pharmacology and Toxicology, Defence Research and Development Establishment, Jhansi Road, Gwalior, India.
Food Chem Toxicol. 2010 Nov;48(11):3171-6. doi: 10.1016/j.fct.2010.08.015. Epub 2010 Aug 20.
The castor seed contains the toxin ricin, one of the most poisonous naturally occurring toxins. The whole of the plant is poisonous, however the seeds are considered the major source of ricin. Ricin exists in different forms in beans of different origin. We investigated the presence of ricin in different isoforms and elucidate some of their structural and biological features isolated from the castor seeds. The isoforms were sub fractionated into ricin I, II and III by chromatography. Their molecular weights lie between 60-65 kDa with difference in their relative electrophoretic mobility. An acidic native PAGE of ricin isoforms at pH 2.9 was performed. Ricin I, II and III are highly cytotoxic against Vero cell line with IC(50) values of 60, 30 and 8 ng/ml respectively. Difference in cytotoxicity of isoforms was confirmed through hemagglutination assay, ricin III caused high degree of hemolysis. The preliminary in vivo toxicity studies showed that ricin III is highly toxic. Immunological studies revealed that anti-ricin I and II antibodies are cross reactive with all the ricin variants, whereas the anti-ricin III antibody is highly specific. The present study shows that anti-ricin I and II antibodies can be used for detection of entire ricin isoforms.
蓖麻种子含有毒蛋白蓖麻毒素，是毒性最强的天然毒素之一。整株植物都有毒，但种子被认为是蓖麻毒素的主要来源。蓖麻毒素以不同的形式存在于不同来源的豆荚中。我们研究了从蓖麻子中分离出的不同同工型蓖麻毒素的存在，并阐明了它们的一些结构和生物学特征。同工型通过色谱法进一步分为 ricin I、II 和 III。它们的分子量在 60-65 kDa 之间，相对电泳迁移率存在差异。在 pH 2.9 的酸性天然 PAGE 上对 ricin 同工型进行电泳。ricin I、II 和 III 对 Vero 细胞系均具有高细胞毒性，IC50 值分别为 60、30 和 8 ng/ml。通过血凝抑制试验证实了同工型的细胞毒性差异，ricin III 引起高度溶血。初步的体内毒性研究表明，ricin III 具有高度毒性。免疫研究表明，抗 ricin I 和 II 抗体与所有 ricin 变体均发生交叉反应，而抗 ricin III 抗体具有高度特异性。本研究表明，抗 ricin I 和 II 抗体可用于检测整个 ricin 同工型。
