1 / 18

Regulation of Virulence Genes

Regulation of Virulence Genes. Salyers & Whitt: Bacterial Pathogenesis: A Molecular Approach ASM Press, 1994 Dorman, C.J: Genetics of Bacterial Virulence. Blackwell Scientific Publications, 1994. Virulence Factors. Invasion Penetration Protection Nutrition Dissemination. Overview.

avalbane
Download Presentation

Regulation of Virulence Genes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Regulation of Virulence Genes Salyers & Whitt: Bacterial Pathogenesis: A Molecular Approach ASM Press, 1994 Dorman, C.J: Genetics of Bacterial Virulence. Blackwell Scientific Publications, 1994

  2. Virulence Factors • Invasion • Penetration • Protection • Nutrition • Dissemination

  3. Overview • Gene Regulation • Genetic Organization • In Vitro Methods for Studying Virulence Factors • Protein Secretion

  4. Environmental Pressures Influencing Virulence Factor Production • Osmolarity • O2 Concentration • CO2 Concentration • pH • O2 and N intermediates • Lack of nutrients • Inorganic ion concentrations

  5. Environmental Modulation vs Phase Variation Antigenic Variation

  6. Genetic Variation in Pathogenic Bacteria • Homologous Recombination • Slip Strand Mispairing • Opa – N. gonorrhoeae – CTCTT • LPS – H. influenzae – CAAT • Pilin – H. Influenzae – TA • Site-specific Recombination • Gene Inversion • Flagellin - S. typhimurium

  7. Phase Variation I: Gene Inversion

  8. Stages in interaction of N.gonorrhoeae with cultured mammalian cells

  9. pilE Antigenic Variation

  10. Phase Variation II: Slipped Strand Mispairing

  11. Transcriptional Regulation • Fur repressor (ferric uptake repression) • AraC transcriptional activator family • LysR transcriptional activator family • Two-Component Regulatory Systems

  12. Ara C Family

  13. LysR Transcriptional Activator Family

  14. Membrane Signal Transduction

  15. Genetic Organization of Virulence Factors: Sources • Plasmid transformation(horizontal gene transfer) e.g Shigella flexneri, Salmonella spp, Yersinia spp, Clostridium tetani. • Phage lysogeny e.g C. botulinus toxins,S. pyogenes, C. diphtheria toxin, Cholera toxin • Pathogenicity Islands • Transposons • Integrons

  16. Pathogenicity Islands • Carriage of many virulence genes • Association with pathogenic species • Different GC content compared to rest of host genome • Association with tRNA genes and/or insertion sequence elements, suggesting phage origin. • Presence of transposable elements • Instability

More Related