Honors & Awards

  • Graduate Research Fellowship Program, National Science Foundation (9/2016-9/2019)
  • Trainee, ChEM-H CBI Predoctoral Program, ChEM-H (9/2015-)

Education & Certifications

  • BS, UC Berkeley, Bioengineering (2015)

All Publications

  • Host Actin Polymerization Tunes the Cell Division Cycle of an Intracellular Pathogen CELL REPORTS Siegrist, M. S., Aditham, A. K., Espaillat, A., Cameron, T. A., Whiteside, S. A., Cava, F., Portnoy, D. A., Bertozzi, C. R. 2015; 11 (4): 499-507


    Growth and division are two of the most fundamental capabilities of a bacterial cell. While they are well described for model organisms growing in broth culture, very little is known about the cell division cycle of bacteria replicating in more complex environments. Using a D-alanine reporter strategy, we found that intracellular Listeria monocytogenes (Lm) spend a smaller proportion of their cell cycle dividing compared to Lm growing in broth culture. This alteration to the cell division cycle is independent of bacterial doubling time. Instead, polymerization of host-derived actin at the bacterial cell surface extends the non-dividing elongation period and compresses the division period. By decreasing the relative proportion of dividing Lm, actin polymerization biases the population toward cells with the highest propensity to form actin tails. Thus, there is a positive-feedback loop between the Lm cell division cycle and a physical interaction with the host cytoskeleton.

    View details for DOI 10.1016/j.celrep.2015.03.046

    View details for Web of Science ID 000353902600001

    View details for PubMedID 25892235

    View details for PubMedCentralID PMC4417095

  • D-Amino Acid Chemical Reporters Reveal Peptidoglycan Dynamics of an Intracellular Pathogen ACS CHEMICAL BIOLOGY Siegrist, M. S., Whiteside, S., Jewett, J. C., Aditham, A., Cava, F., Bertozzi, C. R. 2013; 8 (3): 500-505


    Peptidoglycan (PG) is an essential component of the bacterial cell wall. Although experiments with organisms in vitro have yielded a wealth of information on PG synthesis and maturation, it is unclear how these studies translate to bacteria replicating within host cells. We report a chemical approach for probing PG in vivo via metabolic labeling and bioorthogonal chemistry. A wide variety of bacterial species incorporated azide and alkyne-functionalized d-alanine into their cell walls, which we visualized by covalent reaction with click chemistry probes. The d-alanine analogues were specifically incorporated into nascent PG of the intracellular pathogen Listeria monocytogenes both in vitro and during macrophage infection. Metabolic incorporation of d-alanine derivatives and click chemistry detection constitute a facile, modular platform that facilitates unprecedented spatial and temporal resolution of PG dynamics in vivo.

    View details for DOI 10.1021/cb3004995

    View details for Web of Science ID 000316375500003

    View details for PubMedID 23240806

    View details for PubMedCentralID PMC3601600