THE HONG KONG UNIVERSITY OF SCIENCE & TECHNOLOGY Biology Departmental Seminar
Unique Physiological and Pathogenic Features of Leptospira interrogans Revealed by Whole Genome Sequencing
by
Guoping ZHAO, Ph.D. Professor and Executive Director Chinese National Human Genome Center at Shanghai (CHGCS)
Abstract
Leptospirosis is a widely spread disease of global concern. Infection causes flu-like episodes with frequent severe renal and hepatic damage, such as hemorrhage and jaundice. In more severe cases, massive pulmonary hemorrhages, including fatal sudden haemoptysis, may occur. Here we report the complete genomic sequence of a representative virulent serovar type strain Lai of Leptospira interrogans serogroup Icterohaemorrhagiae consisting of a 4.33-megabase large chromosome (GB: AE010300) and a 359-kilobase small chromosome GB: AE010301 , with a total of 4,769 predicted genes. In terms of the genetic determinants of physiological characteristics, the facultatively parasitic L. interrogans differs extensively from two other strictly parasitic pathogenic spirochetes, Treponema pallidum and Borrelia burgdorferi, though similarities exist in the genes that govern their unique morphological features. A comprehensive analysis of the L. interrogans genes for chemotaxis/motility and LPS synthesis provides a basis for in depth studies of virulence and pathogenesis. The discovery of a series of genes possibly related to adhesion, invasion, and the hematological changes that characterize leptospirosis has provided clues about how an environmental organism might evolve into an important human pathogen.
Abstract Posted by treepatrol (Member # 4117) on :
Lastly, a recently developed animal model now allows us to generate large numbers of mammalian host-adapted spirochetes for further molecular studies. We are utilizing this novel animal model in conjunction with several differentially expressed, plasmid-encoded proteins to help elucidate the signal(s) that result in B. burgdorferi "switching" to the host-adapted phenotype. The overall goal of this research is to gain a better understanding of the dynamics of the host-adaptation process which appears to be an important part of the parasitic strategy of the Lyme disease spirochete.