Cytological Studies on Agrobacterium tumefaciens : 2. Flagella and Their Penatration Canals

Flagella and fimbriae of Agrobacterium tumefaciens, tumor inducing strain At2, were observed by the electron microscopy. Particularly, their numbers, locations and arrangements on the cell body were investigated in association with the ring-like structures on the cell wall sacculus, and the topographical relationship between their locations and growing direction of the cell body was discussed. Results obtained were growing summarized as follows : 1. Two kinds of the ring-like structures, larger one and smaller one, were found on the cell wall sacculus and were proved to be a flagellar and a fimbrial canal, respectively. 2. The morphological observations of the larger canals showed that the number of flagella of this bacterium were usually 5-11 and the location was on the non‐growing subend (mother cell-derived subend) with a circumambiency. The number of fimbriae was about 10 and the location was also on the non-growing end (Photos. 4.6). 3. Although flagella were absent on the growing subend at the early stage of the cell growth, they might appear on the same area by the time of cell division. 4. The author made a correction of the flagellar number in the previous descriptions, from 5-6 to 5-11. The term ”cycrotricheta” or ”circumtricheta” shoud be applied to the flagellation of this bacterium in order to distinguish from the peritricheta, such as Escherichia coli, Proteus vulgaris and other bacteria.