Sigee D C, Smith V A, Hindley J
Microbios. 1982;34(136):113-32.
Tumorigenic and non-tumorigenic strains of Agrobacterium tumefaciens were labelled with tritiated thymidine and added separately to suspension cultures of X-D line habituated tobacco cells. The subsequent association of bacteria with plant host cells and the passage of bacteria and bacterial DNA into these cells was examined by conventional light and electron microscopy and light microscope autoradiography. The results suggest that both strains of bacterium enter damaged host cells (via wall lesions), where they remain restricted to cell vacuoles. By 48 h, the radioactive label has spread from the vacuoles of infiltrated cells to the non-vacuolar cytoplasm of the whole callus tissue. Tumorigenic bacteria differ from the non-tumorigenic strain in promoting a significant increase in host cell nuclear volume, which is paralleled by clear and specific nuclear labelling. It is proposed that tumorigenic DNA, but not non-tumorigenic DNA, is specifically incorporated into, and activates, the host cell nucleus.
用氚标记的胸腺嘧啶核苷对致瘤性和非致瘤性根癌土壤杆菌菌株进行标记，并分别将其添加到适应培养的X-D系烟草悬浮细胞培养物中。通过传统的光学显微镜、电子显微镜和光学显微镜放射自显影技术，研究了随后细菌与植物宿主细胞的结合情况以及细菌和细菌DNA进入这些细胞的过程。结果表明，两种菌株的细菌均通过细胞壁损伤进入受损的宿主细胞，并局限于细胞液泡中。到48小时时，放射性标记已从浸润细胞的液泡扩散到整个愈伤组织的非液泡细胞质中。致瘤性细菌与非致瘤性菌株的不同之处在于，它能促使宿主细胞核体积显著增加，同时伴有清晰而特异的核标记。有人提出，致瘤性DNA而非非致瘤性DNA会特异性地整合到宿主细胞核中并激活细胞核。
