噬菌體Cflc感染對柑桔潰瘍病菌之影響

Abstract

Cflc是一種自柑桔潰瘍病原菌之潛溶性噬體中分離出的線狀噬菌體。宿主細菌在感染Cflc後，在LB及M9CA培養液中，均可見到細胞存活率的明顯降低。電子顯微鏡照片顯示以PTA染色後的感染後細胞，較感染前變得細長，且對染料之通透性增加。感染後的細胞外漏，以β半乳糖??及6-磷酸葡萄醣去氫?之活性測定之，因為二種酵素活性均未在細胞外測得，因此似乎並未自細胞膜上有外漏的現象，但可見到感染後細菌的生理代謝受到改變。以rifampicin處理，可觀察到Cflc感染的細菌對uridine的吸收發生了改變，顯示了因細菌RNA聚合?活性受阻所致使RNA合成之降低，為瞭解宿主RNA聚合?是否參與Cflc的繁殖，以rifampicin加入Cflc感染之細菌，並分析噬菌體後代之產生量及其第一複製形DNA之產生，結果顯示宿主的RNA聚合?參予了噬菌體後代的繁殖。

Cflc is a filamentous phage isolated from lysogenic bacteriophage Cflt of Xanthomonas campestris pv. citri. When host cells were infected by Cflc, the great decrease of cell viability was observed both in LB and in M9CA media, Electron microscopes showed that by PTA negative staining, the infected bacteria became slender and more permeable to the stain. The cell leakage was assayed with the assays of β-galactosidase and glucose-6-phosphate dehydrogenase. The enzyme activities were not detected outside the cells, so it seemed that the leakage did not occur on the cell membrane. The alteration of physiological metabolism in infected bacteria was observed. By using rifampicin treatment we also observed the change in uridine incorporation in Cflc-infected cells, which meant the decrease of RNA synthesis due to a disturbance of bacterial RNA polymerase activity. To understand whether host RNA polymerase was involved in Cflc multiplication, the rifampicin was added into Cflc infected culture, and the production of phage progeny and phage RF DNA replication were analysed. The results showed that host RNA polymerase was involved in the multiplication of Cflc progeny.