| Summary: | 碩士 === 國立清華大學 === 生命科學系 === 90 === Snake venom is a mixture of versatile proteins, they could act independently or cooperatively. The major components of snake venom of Naja naja atra are neurotoxins (cobratoxins), cardiotoxins(CTXs) and PLA2. Among these, the most abundant are CTXs, but they are not the most lethal ones, and the targeting cells can be all kinds of cells in addition to cardiomyocytes. Hence, this phenomenon attracts our attention, but we still do not know the exact mechanism of cellular toxicity of CTXs. According the previous research, the reason for cell death action of CTXs is necrosis, but the intracellular calcium concentration increasing by CTXs treatment might lead cells to another destine — apoptosis.
This thesis is based on the experiment about treatment of Chinese Hamster Ovary (CHO-K1) with CTX A3, we found that after the treatment, cells will go to sub-G1 phase, the types of glycosaminoglycans (GAGs) on the cell surface have no effects on this treatment, no DNA ladder phenomenon and chromatin fragmentation had been observed, we only observed the shrieking of nuclei, but caspase inhibitors and protein synthesis inhibitors had little effects on the sub-G1 phase cells. Besides, when we using Western blotting method to observe the variation of protein quantity, we found in the treatment of high concentration of CTX A3, the amount of pro-caspase 3 andα-tubulin will decrease. And the amount of apoptosis inducing factor (AIF) of Human lymphoblast TK6 cells will increase after treatment of CTX A3. After all these observations, if the effects of CTX A3 on CHO-K1 are mixing type of necrosis and apoptosis still to be studied further.
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