profile picture of Joseph Sorg
  • Professor & Associate Head of Faculty Affairs
Research Areas
  • Cell, Molecular & Developmental
  • Mechanisms of Biological Resilience
  • Microbiology
  • Physiology & Systems Biology

Biography

Joined the Department in 2010

Research Interests

Research Description

My lab is focused on the mechanisms of spore germination and bile acid resistance in Clostridium difficile.  C. difficile is a Gram-positive, spore forming, anaerobe that causes infections in people who have undergone antibiotic regimens.  Previously, we had shown that certain bile acids promote C. difficile spore germination while others inhibit germination.  Bile acids are small molecules made by the liver that help the absorption of fat and cholesterol in the GI tract while also serving as a protective barrier against invading pathogens.  Because C. difficile spores use the ratios of bile acids as cues for germination, the actively growing bacteria must have adapted means to avoid their toxic properties.  We are currently focused on identifying these factors and the mechanisms by which C. difficile spores germinate.

Laboratory Details

Laboratory Address:
Biological Sciences Building East
Room 316
979-845-6233

Educational Background

  • B.S., 2001, Purdue University, Biochemistry.
  • Ph.D., 2006, The University of Chicago, Microbiology.
  • Postdoctoral research: Tufts University School of Medicine.

Selected Publications

    1. Paredes-Sabja, D, Pizarro-Guajardo, M, Sorg, JA. Editorial: Pathogenic clostridia. Anaerobe. 2024;90 :102911. doi: 10.1016/j.anaerobe.2024.102911. PubMed PMID:39284521 .
    2. Osborne, MS, Brehm, JN, Olivença, C, Cochran, AM, Serrano, M, Henriques, AO et al.. The Impact of YabG Mutations on Clostridioides difficile Spore Germination and Processing of Spore Substrates. Mol Microbiol. 2024;122 (4):534-548. doi: 10.1111/mmi.15316. PubMed PMID:39258427 .
    3. Nerber, HN, Baloh, M, Brehm, JN, Sorg, JA. The small acid-soluble proteins of Clostridioides difficile regulate sporulation in a SpoIVB2-dependent manner. PLoS Pathog. 2024;20 (8):e1012507. doi: 10.1371/journal.ppat.1012507. PubMed PMID:39213448 PubMed Central PMC11392383.
    4. Martins, D, Nerber, HN, Roughton, CG, Fasquelle, A, Barwinska-Sendra, A, Vollmer, D et al.. Cleavage of an engulfment peptidoglycan hydrolase by a sporulation signature protease in Clostridioides difficile. Mol Microbiol. 2024;122 (2):213-229. doi: 10.1111/mmi.15291. PubMed PMID:38922761 PubMed Central PMC11309906.
    5. Osborne, MS, Brehm, JN, Olivença, C, Cochran, AM, Serrano, M, Henriques, AO et al.. The impact of YabG mutations on C. difficile spore germination and processing of spore substrates. bioRxiv. 2024; :. doi: 10.1101/2024.06.10.598338. PubMed PMID:38915615 PubMed Central PMC11195116.
    6. Brehm, JN, Sorg, JA. Theophylline-based control of repA on a Clostridioides difficile plasmid for use in allelic exchange. Anaerobe. 2024;88 :102858. doi: 10.1016/j.anaerobe.2024.102858. PubMed PMID:38692475 .
    7. Nerber, HN, Sorg, JA. The small acid-soluble proteins of spore-forming organisms: similarities and differences in function. Anaerobe. 2024;87 :102844. doi: 10.1016/j.anaerobe.2024.102844. PubMed PMID:38582142 .
    8. Marini, E, Olivença, C, Ramalhete, S, Aguirre, AM, Ingle, P, Melo, MN et al.. A sporulation signature protease is required for assembly of the spore surface layers, germination and host colonization in Clostridioides difficile. PLoS Pathog. 2023;19 (11):e1011741. doi: 10.1371/journal.ppat.1011741. PubMed PMID:37956166 PubMed Central PMC10681294.
    9. Nerber, HN, Baloh, M, Brehm, JN, Sorg, JA. The small acid-soluble proteins of Clostridioides difficile regulate sporulation in a SpoIVB2-dependent manner. bioRxiv. 2024; :. doi: 10.1101/2023.05.17.541253. PubMed PMID:37292792 PubMed Central PMC10245694.
    10. Aguirre, AM, Adegbite, AO, Sorg, JA. Clostridioides difficile bile salt hydrolase activity has substrate specificity and affects biofilm formation. NPJ Biofilms Microbiomes. 2022;8 (1):94. doi: 10.1038/s41522-022-00358-0. PubMed PMID:36450806 PubMed Central PMC9712596.
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