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Chapter 11 : Treponomics: Treponema denticola Genome and Functions
Category: Genomics and Bioinformatics
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This chapter reviews current progress in applying Treponema denticola genome information to the research areas and suggests some topics that have yet to be addressed adequately by the research community. A group of seven genes was identified by homology with TP0155, a fibronectin-binding protein of T. pallidum. While five of these proteins showed at least some fibronectin-binding activity in recombinant form, only one was clearly demonstrated to be surface localized. This study provides a rational basis for further examination of the relative contribution of these proteins to T. denticola interactions with fibronectin. The T. pallidum repeat (tpr) genes, which encode paralogous proteins with sequence similarity to major surface protein (Msp) of T. denticola, were expressed at relatively low levels. This study, as well as numerous similar studies of other pathogens, demonstrates the potential utility of in vivo microarray analysis of bacterial gene expression. The current paucity of microarray-based T. denticola global expression analysis is likely the result of several factors. As in many bacteria, the T. denticola genome contains genes that appear to be more closely related to those of eukaryotes or archaea than to those of other bacteria. Several groups are investigating various aspects of T. denticola molecular physiology, especially as it relates to microbial community ecology and periodontal pathogenesi. In addition to the continued need to characterize putative virulence determinants very little is known about several important biological components of these cells, including nutrient uptake and processing, secretion and efflux systems, and various lipids and lipid-containing molecules.
Composite immunogold transmission electron micrograph showing a T. denticola ATCC 35405 dividing cell labeled with immunoglobulins raised against the PrtP protease complex (dentilisin). The hexagonal array of Msp complex is also visible in the outer membrane. The inset shows an enlargement of the indicated region. Bars, 300 nm. Original photographs courtesy of B. C. McBride.