Charon N W, Goldstein S F, Curci K, Limberger R J
Department of Microbiology and Immunology, West Virginia University, Morgantown 26506.
J Bacteriol. 1991 Aug;173(15):4820-6. doi: 10.1128/jb.173.15.4820-4826.1991.
Treponema phagedenis Kazan 5 is a spirochete with multiple periplasmic flagella attached near each end of the cell cylinder. Dark-field microscopy revealed that most of the cell is right-handed (helix diameter, 0.23 micron; helix pitch, 1.74 microns), and the ends appear bent. These ends could move and gyrate while the central part of the cell remained stationary. The present study examines the basis for the bent-end characteristic. Motility mutants deficient in periplasmic flagella were found to lack the bent ends, and spontaneous revertants to motility regained the periplasmic flagella and bent-end characteristic. The length of the bent ends (2.40 microns) was found to be similar to the length of the periplasmic flagella as determined by electron microscopy (2.50 microns). The helix diameter of the bent ends was 0.57 micron, and the helix pitch of the bent ends was 1.85 microns. The periplasmic flagella were short relative to the length of the cells (15 microns) and, in contrast to the reports of others, did not overlap in the center of the cell. Similar results were found with T. phagedenis Reiter. The results taken together indicate that there is a causal relationship between the bent-end morphology and the presence of short periplasmic flagella. We report the first three-dimensional description of spirochete periplasmic flagella. Dark-field microscopy of purified periplasmic flagella revealed that these organelles were left-handed (helix diameter, 0.36 microns; helix pitch, 1.26 microns) and only 1 to 2 wavelengths long. Because of a right-handed cell cylinder and left-handed periplasmic flagella along with bent ends having helix diameters greater than those of either the cell cylinder or periplasmic flagella, we conclude that there is a complex interaction of the periplasmic flagella and the cell cylinder to form the bent ends. The results are discussed with respect to a possible mechanism of T. phagedenis motility.
溃蚀性密螺旋体菌喀山5型是一种螺旋体，在细胞圆柱体的两端附近附着有多根周质鞭毛。暗视野显微镜观察显示，细胞的大部分呈右旋（螺旋直径0.23微米；螺旋间距1.74微米），且两端似乎弯曲。当细胞的中央部分保持静止时，这些末端可以移动和旋转。本研究探讨了末端弯曲特征的基础。发现缺乏周质鞭毛的运动突变体没有弯曲的末端，而自发回复到有运动能力的菌株则重新获得了周质鞭毛和末端弯曲的特征。通过电子显微镜测定，发现弯曲末端的长度（2.40微米）与周质鞭毛的长度（2.50微米）相似。弯曲末端的螺旋直径为0.57微米，弯曲末端的螺旋间距为1.85微米。周质鞭毛相对于细胞长度（15微米）较短，并且与其他报道不同的是，它们在细胞中央不重叠。在赖特尔氏密螺旋体菌中也发现了类似结果。综合这些结果表明，末端弯曲形态与短周质鞭毛的存在之间存在因果关系。我们报告了螺旋体周质鞭毛的首次三维描述。纯化的周质鞭毛的暗视野显微镜观察显示，这些细胞器呈左旋（螺旋直径0.36微米；螺旋间距1.26微米），且长度仅为1至2个波长。由于细胞圆柱体为右旋，周质鞭毛为左旋，以及弯曲末端的螺旋直径大于细胞圆柱体或周质鞭毛的螺旋直径，我们得出结论，周质鞭毛与细胞圆柱体之间存在复杂的相互作用以形成弯曲末端。讨论了这些结果与溃蚀性密螺旋体菌运动可能机制的关系。
