Affiliation:
1. David Axelrod Institute for Public Health, Wadsworth Center, New York State Department of Health, Albany, New York 12201-2002
Abstract
ABSTRACT
Unique cytoplasmic filaments are found in the treponeme genus of spirochete bacteria. Their function is unknown, but their location underneath the periplasmic flagellar filaments (PFF) suggests a role in motility and/or cell structure. To better understand these unique structures, the gene coding for the cytoplasmic filaments,
cfpA
, was identified in various treponemal species.
Treponema phagedenis cfpA
was 2,037 nucleotides long, and the encoded polypeptide showed 78 to 100% amino acid sequence identity with the partial sequence of CfpA from
T. denticola
,
T. vincentii
, and
T. pallidum
subsp.
pertenue
. Wild-type
T. phagedenis
and a PFF-deficient isolate were analyzed by electron microscopy to assess the structural relationship of the cytoplasmic filaments and the PFF. The number of cytoplasmic filaments per cell of
T. phagedenis
(mean, 5.7) was compared with the number of PFF at each end of the cell (mean, 4.7); the results suggest that there is no direct one-to-one correlation at the cell end. Moreover, a structural link between these structures could not be demonstrated. The cytoplasmic filaments were also analyzed by electron microscopy at different stages of cell growth; this analysis revealed that they are cleaved before or during septum formation and before the nascent formation of PFF. A PFF-deficient mutant of
T. phagedenis
possessed cytoplasmic filaments similar to those of the wild type, suggesting that intact PFF are not required for their assembly and regulation. The extensive conservation of CfpA among pathogenic spirochetes suggests an important function, and structural analysis suggests that it is unlikely that the cytoplasmic filaments and the flagellar apparatus are physically linked.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
24 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献