Analysis of the activation and mode of action of Clostridium perfringens ε-toxin

1.通过λ-毒素、胰蛋白素和环球蛋白素的激活（ε-prototoxin）被试验过梭菌、胰蛋白素和环球蛋白素。小鼠血清素测试显示了含有和不含原毒素的50%血清剂量（LD-D250-D2）的血清素治疗剂量为110和70，000纳克/千克，适当地。D2 of the prototoxin treated with trypsin and trypsin plus chymotrypsin were 320 and 65 ng/kg的身体重量，对。确定每个激活的8-prototoxin的N-terminal氨基酸序列的N-terminal amino acid序列被揭示出来，在第10和第11个prototoxin中清除了λ-毒素，同时trypsin和trypsin加上chymotrypsin在第13和第14个氨基酸酯之间也被清除。从分子重量中提取的C-终端被放置在Prototoxin的第23或第30个氨基酸住院医师的C-终端，建议不仅去除N-，而且C-终端肽也对Prototoxin的激活负责。“ε-毒素的神经毒性是通过大鼠大脑的历史学研究来进行的。注射α-毒素在亚硫酸剂量（50纳克/千克）中造成的神经损伤，预先在Hippoampus中造成神经损伤：显示的Hippoampus有标记的收缩和毛细血管中毒中的金字塔细胞，以及细胞失去对微管相关蛋白2的免疫活性（MAP-2）。Timm's Zinc staining revealed，即zinc ions were depleted in the mossy layers of the CA 3 subfield含有glutamate作为synaptic transmitter。无论是谷氨酰胺释放抑制剂还是谷氨酰胺受体拮抗剂的先前注射，都受到8-毒素的神经损伤保护。这些结果建议8-毒素对glutamatergic系统和evokes对glutamate的特别释放，导致神经损伤。

1. The activation of Clostridium perfringens epsilon-prototoxin (ε-prototoxin) by λ-toxin, trypsin and chymotrypsin was examined. The mouse lethality test showed that the 50% lethal doses (LDィイD250ィエD2) of the prototoxin with and without λ-toxin treatment were 110 and 70,000 ng/kg of body weight, respectively. LDィイD250ィエD2 of the prototoxin treated with trypsin and trypsin plus chymotrypsin were 320 and 65 ng/kg of body weight, respectively. Determination of the N-terminal amino acid sequence of each activated 8-prototoxin revealed that λ-toxin cleaved between the 10th and 11th amino acid residues from the N-terminus of the prototoxin, while trypsin and trypsin plus chymotrypsin did so between the 13th and 14th amino acid residues. The C-terminus deduced from the molecular weight is located at the 23th or 30th amino acid residue from the C-terminus of the prototoxin, suggesting that removal of not only N- but also C-terminal peptides is responsible for the activation of the prototoxin.2. The neurotoxicity of ε-toxin was examined by histological examination of the rat brain. Injection of ε-toxin at a sublethal dose, 50 ng/kg, caused neuronal damage predominantly in the hippocampus: pyramidal cells in the hippocampus showed marked shrinkage and karyopyknosis, and the cells lost the immunoreactivity to microtubule-associated protein 2 (MAP-2). Timm's zinc staining revealed that zinc ions were depleted in the mossy layers of the CA3 subfield containing glutamate as a synaptic transmitter. Prior injection of either a glutamate-release inhibitor or glutamate-receptor antagonist protected the hippocampus from the neuronal damage caused by 8-toxin. These results suggest that 8-toxin acts on the glutamatergic system and evokes excessive release of glutamate, leading to neuronal damage.