The University of Massachusetts Amherst

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M. Sloan Siegrist

Assistant Professor

The cell envelope is an essential interface between a bacterium and its surroundings. This dynamic structure accommodates the basic cellular processes of growth and division while protecting against environmental and immune insults. Because it is essential for viability and is composed in part of molecules that are not present in host cells, the bacterial cell envelope has been a particularly fruitful target for antibiotic development. Both the remarkable biology and medical potential of the cell envelope have inspired steady research on the topic for over half a century. Indeed, cell envelope synthesis and remodeling are well described for model bacteria replicating in broth culture. However, the vast majority of species are unlikely to fit this paradigm neatly. Moreover, these processes have been primarily studied under defined conditions that may or may not recapitulate the natural environment.

Current Research
Our research focuses on the cell envelope of intracellular pathogens such as Mycobacterium tuberculosis and Listeria monocytogenes. The broad goals of our lab are (1) to determine the mechanisms by which these pathogens adapt their cell envelope to the host environment and (2) to engineer the bacterial cell envelope for basic and translational biomedical applications. To tackle these challenges, we draw from multiple disciplines and develop new tools when appropriate.

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Academic Background

  • BA Human Biology, Stanford University
  • PhD Immunology and Infectious Diseases, Harvard School of Public Health
  • Postdoctoral training: Department of Chemistry, U.C. Berkeley
Siegrist MS, Aditham AK, Espaillat A, Cameron TA, Whiteside SA, Cava F, Portnoy DA, Bertozzi CR. Host actin polymerization tunes the cell division cycle of an intracellular pathogen. Cell Rep. 2015 Apr 28;11(4):499-507. Epub 2015 Apr 16. PubMed PMID: 25892235.
Siegrist MS, Swarts BM, Fox DM, Lim SA, Bertozzi CR. Illumination of growth, division and secretion by metabolic labeling of the bacterial cell surface. FEMS Microbiol Rev. 2015 Mar;39(2):184-202. Epub 2015 Jan 23. Review. PubMed PMID: 25725012.
Meniche X, Otten R, Siegrist MS, Baer CE, Murphy KC, Bertozzi CR, Sassetti CM. Subpolar addition of new cell wall is directed by DivIVA in mycobacteria. Proc Natl Acad Sci U S A. 2014 Aug 5;111(31):E3243-51. Epub 2014 Jul 21. PubMed PMID: 25049412.
Siegrist MS, Steigedal M, Ahmad R, Mehra A, Dragset MS, Schuster BM, Philips JA, Carr SA, Rubin EJ. Mycobacterial Esx-3 requires multiple components for iron acquisition. mBio. 2014 May 6;5(3):e01073-14. PubMed PMID: 24803520.
Shieh P, Siegrist MS, Cullen AJ, Bertozzi CR. Imaging bacterial peptidoglycan with near-infrared fluorogenic azide probes. Proc Natl Acad Sci U S A. 2014 Apr 15;111(15):5456-61. Epub 2014 Mar 31. PubMed PMID: 24706769.
Siegrist MS, Whiteside S, Jewett JC, Aditham A, Cava F, Bertozzi CR. (D)-Amino acid chemical reporters reveal peptidoglycan dynamics of an intracellular pathogen. ACS Chem Biol. 2013 Mar 15;8(3):500-5. Epub 2013 Jan 11. PubMed PMID: 23240806.
Swarts BM, Holsclaw CM, Jewett JC, Alber M, Fox DM, Siegrist MS, Leary JA, Kalscheuer R, Bertozzi CR. Probing the mycobacterial trehalome with bioorthogonal chemistry. J Am Chem Soc. 2012 Oct 3;134(39):16123-6. Epub 2012 Sep 24. PubMed PMID: 22978752.
Siegrist MS, Unnikrishnan M, McConnell MJ, Borowsky M, Cheng TY, Siddiqi N, Fortune SM, Moody DB, Rubin EJ. Mycobacterial Esx-3 is required for mycobactin-mediated iron acquisition. Proc Natl Acad Sci U S A. 2009 Nov 3;106(44):18792-7. Epub 2009 Oct 21. PubMed PMID: 19846780.
Contact Info

Department of Microbiology
110 Morrill IV North
639 North Pleasant Street
Amherst, MA 01003-9292

(413) 545-2735