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標題: | 線狀噬菌體Cflt imm-的特性 Characterization of filamentous phage Cflt imm- |
作者: | 陳松芸 |
出版年 : | 1992 |
學位: | 碩士 |
摘要: | 線狀噬菌體Cflt感染寄主細胞柑橘潰瘍病病原菌(Xanthomonas campestris pv. citri)後,會將其DNA插入寄主細胞染色體,寄主細胞即形成一穩定之潛溶菌,且潛溶菌本身不會再被Cflt感染,然而,我們卻從Cflt潛溶菌中分離得到一噬菌體突變株,經純化後它能夠再感染Cflt潛溶菌,因Cflt潛溶菌對其失去免疫力,故命名?Cflt imm-。 此突變株Cflt imm-有數點特性不同於Cflt,突變株Cflt imm-感染寄主細胞後所形成的溶菌斑較小,且在寄主細胞中所產生之噬菌體複製型(RF)DNA較少。寄主細胞受Cflt與Cflt imm-感染後所形成的菌落形態有明顯差異,受Cflt imm-感染的寄主細胞會形成大、小兩型菌落,然而受Cflt感染的寄主細胞卻只形成大的菌落。受噬菌體感染後的細胞所形成的菌落數目會比未受感染細胞低,而這種降低的情形Cflt imm-又較Cflt來得明顯。經由微培養技術在光學顯微鏡下觀察,受Cflt imm-感染2、4、8小時後,不分裂細胞的百分率由2小時的5%增至8小時的25%,而以同樣的情形觀察受Cflt感染後不分裂細胞由2小時的2%增至8小時的8%,由此可知,Cflt imm-的感染對寄主細胞的生長有較強的抑制作用。此外,將負責Cflt含有插入染色體功能的片段殖入含有篩選標誌的質體(vector)中,送入寄主細胞內,經由抗生素篩選,可說明Cflt具有插入(integration)功能,但是,在Cflt imm-的相同片段,利用同樣方式,卻未能檢視出其具有插入功能。 Cflt imm-, a mutant of Cflt, was isolated from a culture of Cflt lysogene. It can superinfect Cflt lysogen, and named accordingly Cflt imm-. There are several different characteristics between Cflt and Cflt imm- stated as following: the plaque of Cflt imm- is smaller than that of the Cflt; Cflt imm- produces less RF DNA than Cflt does; small colonies were found in Cflt imm--infected cell, but Cflt-infected cell formed large colonies; the growth rate of Cflt-infected cell was only slightly reduced comparing with the uninfected cell, but the growth rate of Cflt imm--infected cell was drastically reduced. Investigated by microculture technique, the frequency of undivided cells in Cflt imm--infected cells was higher than that of Cflt-infected cells suggesting that Cflt imm- inhibited strongly the growth rate of host cells. Besides, the putative DNA fragment that controls the integration of Cflt into the host chromosom has been cloned in E. coli using a vector containing Kanamycin resistant gene as a selection marker. The tranformed bacteria will grow on the Kanamycin containing medium only when the plasmid integrates into the X. C. C. chromosome. But, by the same methodology, the same fragment of Cflt imm- failed to integrate into the host chromosome. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/75880 |
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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