References:
- Lin, T., L. Gao, D. G. Edmondson, M. B. Jacobs, M. T. Philipp, and S. J. Norris. 2009. Central role of the Holliday junction helicase RuvAB in vlsE recombination and infectivity of Borrelia burgdorferi. PLoS Pathog. 5:e1000679. Article
- Liu, J., T. Lin, D. J. Botkin, E. McCrum, H. Winkler, and S. J. Norris. 2009. Intact flagellar motor of Borrelia burgdorferi revealed by cryo-electron tomography: Evidence for stator ring curvature and rotor/C ring assembly flexion. J. Bacteriol. 191: 5026-36. Abstract
- Coutte, L., D. J. Botkin, L. Gao, and S. J. Norris. 2009. Detailed analysis of sequence changes occurring during vlsE antigenic variation in the mouse model of Borrelia burgdorferi infection. PLoS Pathogens 5: e1000293. Abstract
- Matejková P, Strouhal M, Smajs D, Norris SJ, Palzkill T, Petrosino JF, Sodergren E, Norton JE, Singh J, Richmond TA, Molla MN, Albert TJ, Weinstock GM. Complete genome sequence of Treponema pallidum ssp. pallidum strain SS14 determined with oligonucleotide arrays. BMC Microbiol. 2008 May 15;8:76. Abstract
- Brinkman, M.B., M. A. McGill, J. Petterson, A. Rogers, P. Matějková, D. Šmajs, G. M. Weinstock, S. J. Norris and T. Palzkill. 2008. A novel Treponema pallidum antigen, TP0136, is an outer membrane protein that binds human fibronectin. Infect. Immun. 76:1848-1857. Abstract
- Strouhal, M., D. Smajs, P. Matejkova, E. Sodergren, A. G. Amin, J. K. Howell, S. J. Norris, and G. M. Weinstock. 2007. Genome differences between Treponema pallidum subsp. pallidum strain Nichols and T. paraluiscuniculi strain Cuniculi A. Infect. Immun. 75: 5859-5866. Abstract
- Embers, M. E., F. T. Liang, J. K. Howell, M. B. Jacobs, J. E. Purcell, S. J. Norris, B. J. Johnson, and M. T. Philipp. 2007. Antigenicity and recombination of VlsE, the antigenic variation protein of Borrelia burgdorferi, in rabbits, a host putatively resistant to long-term infection with this spirochete. FEMS Immunol. Med. Microbiol. 50:421-429. Abstract
- Botkin, D. J., A. N. Abbott, P. E. Stewart, P. A. Rosa, H. Kawabata, H. Watanabe, and S. J. Norris. 2006. Identification of potential virulence determinants by Himar1 transposition of infectious Borrelia burgdorferi B31. Infect. Immun. 74:6690-9. Abstract
Steven J. Norris, PhD
Greer Professor & Vice Chair for Research
Pathology & Laboratory Medicine
(713) 500 - 5338
Steven.J.Norris@uth.tmc.edu
Bacterial Pathogenesis and Host-Pathogen Interactions
Education
M.S. Biology/Biochemistry, UC Santa Barbara, 1975
Ph.D. Microbiology & Immunology, UCLA, 1980
Postgraduate Training
Postdoctoral Fellowship, UC San Diego, 1980-1982
Areas of Interest
Our research is driven by an interest in bacterial pathogenesis and its relationship with microbial physiology, structure, and genetics. Borrelia burgdorferi (which causes Lyme disease) and Treponema pallidum (the causative agent of syphilis) are spirochetes that cause chronic, multisystemic diseases. These organisms can invade almost any tissue and survive and cause disease in the host for years to decades, and thus serve as excellent models for the study of persistent, invasive pathogens. In the case of B. burgdorferi, molecular genetic techniques such as transposon mutagenesis (including signature tagged mutagenesis), PCR, Luminex®-based high-throughput screening procedures, and reverse genomics are being utilized in combination with infectivity studies to identify genes and gene products required for infectivity in a mouse model. Thus far, we have identified and characterized the vls antigenic variation of B. burgdorferi, an elaborate mechanism similar to the Variable Major Protein system of relapsing fever borreliae. In addition, we have determined that the linear plasmids lp25 (and its encoded gene pncA) and lp28-1 are required for full virulence of B. burgdorferi during infection in mice. We are currently taking a global approach to identify additional genes encoding virulence determinants important in the pathogenesis of Lyme disease, as well as genes required for vls recombination and immune evasion. Little is known about T. pallidum due to the inability to culture the organism continuously in vitro. In collaboration with Dr. George Weinstock and the Institute of Genomic Research in Rockville, Md., the complete sequence analysis of the 1.14 megabase chromosome of T. pallidum was completed in 1998; the genome sequences of several related subspecies and strains have also been determined using second generation sequencing approaches. The sequence of the 2.84 megabase genome of Treponema denticola, an oral spirochete involved in periodontal disease, was published in April 2004. We are currently applying ‘functional genomics’ to the elucidation metabolism, structure, and pathogenic mechanisms of these spirochetes. In addition, cryo-electron tomography, a relatively new electron microscopy technique that creates 3D images of bacteria, is being utilized in collaborative studies with Dr. Jun Liu to elucidate the architecture of the flagellar motor and other structural elements of these organisms.
