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標題: | 線狀噬菌體f1的澄清狀溶菌斑突變株C214之研究 Studies on a Clear-Plaque Mutant C214 of the Filamentous Bacteriophage f1 |
作者: | 陳文彬 |
出版年 : | 1990 |
學位: | 碩士 |
摘要: | 從培養中的野生型線狀噬菌體f1的混濁狀溶菌斑(turbid plaque)挑到一個澄清狀溶菌斑(clear plaque)f1突變株C214。實驗證據顯示C214是一個過量製造其DNA和基因II蛋白的突變株。根據前人研究顯示R491是一個基因II mRNA前導序列(leader sequence)突變的突變株。基於C214與R491蛋白電泳圖的差異,以及兩者可互補的結果,推測C214是基因V突變的噬菌體。由於C214可正常生長,此突變的基因V蛋白可能仍然具有與單股DNA鍵結的能力。 以微生物,生化和放射線標誌技術作系統研究,顯示C214的感染會造成寄主的死亡,其病徵包括細胞膜電位大量喪失,細胞膜通透能力增加,以及細胞內含物外漏。穿透式電子顯微鏡觀察顯示在死亡細胞內有大量膜狀顆粒的產生。更且,被C214感染的寄主在感染後期發現有噬菌體外鞘蛋白,即基因VIII蛋白,大量堆積在內胞膜。這個結果支援前人假設,他們認為噬菌體組合和釋放相關基因的突變造成細胞死亡和相似於上述病徵的產生是因為基因VIII蛋白在內胞膜的堆積所致。C214感染的寄主內胞膜上也大量堆積基因V蛋白,顯示其組合和釋放曾受到阻礙。這個現象推測是因為噬菌體和寄主巨分子合成無法相互配合所致。此外,細胞膜結構破壞的原因可能來自外胞膜蛋白的缺失和減少。 A clear plaque mutant C214 is picked from a culture of turbid plaque wild-type fl. Experimental evidences have shown that C214 is a mutant in which both the phage DNA and gene II protein are over-produced. According to previous studies, investigators have shown that R491 is mutated in the gene II mRNA leader sequence. Based on the different protein gel patterns and the successful complementation test between C214 and R491, it is suggested that C214 is a gene V-mutated phage. Since C214 has normal growth, it is also suggested that the mutated gene V protein retains it's single-stranded DNA binding activity. Systematically investigated by microbiological, biochemical and radiation labelling techniques, it is concluded that the infection of C214 causes death of the host cells in addition to symptoms conclude loss of membrane potential, permeabilization of cell envelope and leakage of cell contents. Observation from transmission electron microscopic has shown that a lot of membranous granules are produced in the dead cells. Furthermore, excessive accumulation of the phage coat protein, gene VIII protein, has been observed in the inner membrane of the C214-infected cells at late stage of infection. This datum supports a previous hypothesis which suggests that both cell death and the symptom changes caused by the infection of the assembly or extrusion-related gene mutants are results of the accumulation of the gene VIII protein in the inner membrane. Also, the gene V protein is accumulated in the inner membrane of the C214-infected cells, suggesting that the phage assembly and extrusion is blocked at a certain stage. It is proposed that this phenomena is a result of the imbalance between the macromolecule synthesis of C214 and that of the host cell. In addition, cell membrane damage could be from the depletion and the loss of the outer membrane proteins. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/75762 |
全文授權: | 未授權 |
顯示於系所單位: | 植物科學研究所 |
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