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J. Mol. Micro. Biotechnol. 3: 37-62
Biology of Treponema pallidum: Correlation of Functional Activities With Genome Sequence Data
Steven J. Norris, David L. Cox, and George M. Weinstock
Aspects of the biology of T. pallidum subsp.
pallidum, the agent of syphilis, are examined in the context of a century of experimental studies and the
recently determined genome sequence. T. pallidum
and a group of closely related pathogenic spirochetes have evolved to become highly invasive, persistent pathogens
with little toxigenic activity and an inability to survive outside the mammalian host. Analysis of the genome sequence confirms morphologic studies indicating the lack
of lipopolysaccharide and lipid biosynthesis mechanisms, as well as a paucity of outer membrane protein candidates. The metabolic capabilities and adaptability of
T. pallidum are minimal, and this relative deficiency is reflected by the absence of many pathways, including the tricarboxylic acid cycle, components of
oxidative phosphorylation, and most biosynthetic pathways. Although multiplication of
T. pallidum has been obtained in a tissue culture system, continuous in vitro culture
has not been achieved. The balance of oxygen utilization and toxicity is key to the survival and growth of
T. pallidum, and the genome sequence reveals a similarity to
lactic acid bacteria that may be useful in understanding this relationship. The identification of relatively few genes potentially involved in pathogenesis reflects our lack
of understanding of invasive pathogens relative to toxigenic organisms. The genome sequence will provide useful raw data for additional functional studies on
the structure, metabolism, and pathogenesis of this enigmatic organism.
Full article [pdf]
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