Battelle-C. F. Kettering Research Laboratory, Yellow Springs, Ohio 45387.
Appl Environ Microbiol. 1986 Jul;52(1):134-41. doi: 10.1128/aem.52.1.134-141.1986.
Pili (fimbriae) were observed on cells of each of the five strains of Bradyrhizobium japonicum and the one strain of Rhizobium trifolii examined. Pili on B. japonicum were about 4 nm in diameter and polarly expressed. Piliated cells were estimated by transmission electron microscopy and hydrophobic attachment to polystyrene to constitute only a small percentage of the total population. The proportion of piliated cells in these populations was dependent on culture age in some strains. Piliated B. japonicum cells were selectively and quantitatively removed from suspension when cultures were incubated with either soybean roots or hydrophobic plastic surfaces, indicating that pili were involved in the attachment of the bacteria to these surfaces. Pili from B. japonicum 110 ARS were purified and found to have a subunit molecular weight of approximately 21,000. Treatment of B. japonicum suspensions with antiserum against the isolated pili reduced attachment to soybean roots by about 90% and nodulation by about 80%. Pili appear to be important mediators of attachment of B. japonicum to soybean roots under the conditions examined.
在研究的 5 株日本根瘤菌和 1 株三叶草根瘤菌的细胞上都观察到了菌毛（纤毛）。日本根瘤菌的菌毛直径约为 4nm，极性表达。通过透射电子显微镜和聚苯乙烯的疏水性附着估计有菌毛的细胞仅占总细胞数的一小部分。在某些菌株中，这些群体中菌毛细胞的比例取决于培养年龄。当培养物与大豆根或疏水性塑料表面孵育时，从悬浮液中选择性和定量地去除有菌毛的日本根瘤菌细胞，表明菌毛参与了细菌与这些表面的附着。从日本根瘤菌 110 ARS 中纯化的菌毛，发现其亚基分子量约为 21000。用针对分离菌毛的抗血清处理日本根瘤菌悬浮液，使对大豆根的附着减少约 90%，结瘤减少约 80%。菌毛似乎是日本根瘤菌在研究条件下附着于大豆根的重要介质。
