Cheryl Whistler

Phone: (603) 862-2359
Office: Molecular, Cellular, & Biomedical Sciences, Rudman Hall Rm 208, Durham, NH 03824

Description of Current Research :
Either harmful or beneficial bacterium-host interactions can trigger similar host-responses that respectively result in eradication or tolerance of the bacterium. How bacteria can appropriately communicate to a host its benign naturre and how hosts can discriminate between harmful and beneficial bacteria is poorly understood. Using as a model system they symbiosis of the bioluminescent bacterium, Vibrio fischeri, with its animal host, the squid Euprymna scolopes, my research seeks to elucidate how bacteria initiate and maintain long-term associations and how hosts recognize and respond to their desired symbiotic partner.
Symbiotic colonization is a dynamic process that requires adaptation by both partners. The host is an active participant during initiation of the symbiotic association, collecting bacteria from the surrounding seawater in mucus it secretes from paired epithelial appendages attached to the light organ and concentrating them near the entrance to the organ that eventually cultures the bacterial symbiont. Although various bacterial species associate with the mucus, only the correct symbiont, V. fischeri, is able to successfully enter into symbiosis by overcoming host-imposed checkpoints. Studies indicate that during the specific cooperative association between V. fisheri and its squid host, the baacterial two-component regulator GacA, coordinately regulates the expression of bacterial traits that alllow it to initiate a benign infection of the squid's light-emitting organ. GacA mutants of V. fischeri are less effective at initiating infection and are also impaired at forming tight aggregates during infection. When its light organ is colonized by V. fischeri, the squid host adapts to this association and, in response to bacterial signals, undergoes a program of changes that leads to the normal develoment of the light organ. One of the most striking changes is apoptosis in and regression of the appendages over a four-day period. GacA mutants that successfully colonize squid light organs do not trigger normal apoptosis during regression of these appendages, implying that delivery of bacterial signals to the squid host is GacA-controlled. Furthermore, GacA mutants fail to trigger cessation of mucus shedding, a colonization response that normally limits further bacterial interaction.

My current research focus will use the GacA mutant as a basis for identifying and characterization colonization traits. These studies will provide insight into bacteria-derived signals that allow hosts to respond appropriately to beneficial organisms, thus allowing association, without compromising the ability of immune responses to protect the host from pathogenic infection. We are currently utilizing a recently generated DNA microarray of the entire genome of V. fischeri, and will also combine this genomic approach with random mutagenesis screens to discover previously uncharacterized genes and traits that contribute to animal tissue colonization.

Courses Taught

  • BCHM/BMCB 854/754: Molecular Biol Research Methds
  • BMCB 754: Molecular Biol Research Methds
  • BMS 750: Case Studies in Microbiology
  • GEN 704: Genetics Prokaryotic Microbes
  • GEN 704/804: Genetics Prokaryotic Microbes
  • INCO 590: Rsrch Exp/MCBS
  • INCO 790: Advanced Research Experience
  • MCBS 905: Contemp Top Molec/Cell/Biomed
  • MCBS 997: Seminar
  • MCBS 999: Doctoral Thesis


  • Ph.D., Molecular and Cellular Biology, Oregon State University
  • B.A., General Biology, University of California - San Diego

Selected Publications

  • Foxall, R. L., Means, J., Marcinkiewicz, A. L., Schillaci, C., DeRosia-Banick, K., Xu, F., . . . Whistler, C. A. (2024). Inoviridae prophage and bacterial host dynamics during diversification, succession, and Atlantic invasion of Pacific-native Vibrio parahaemolyticus.. mBio, 15(1), e0285123. doi:10.1128/mbio.02851-23

  • Xu, F., Gonzalez-Escalona, N., Drees, K. P., Sebra, R. P., Cooper, V. S., Jones, S. H., & Whistler, C. A. (2017). Parallel Evolution of Two Clades of an Atlantic-Endemic Pathogenic Lineage of Vibrio parahaemolyticus by Independent Acquisition of Related Pathogenicity Islands. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 83(18). doi:10.1128/AEM.01168-17

  • Pankey, M. S., Foxall, R. L., Ster, I. M., Perry, L. A., Schuster, B. M., Donner, R. A., . . . Whistler, C. A. (2017). Host-selected mutations converging on a global regulator drive an adaptive leap towards symbiosis in bacteria. ELIFE, 6. doi:10.7554/eLife.24414

  • Xu, F., Gonzalez-Escalona, N., Haendiges, J., Myers, R. A., Ferguson, J., Stiles, T., . . . Whistler, C. A. (2017). Sequence Type 631 Vibrio parahaemolyticus, an Emerging Foodborne Pathogen in North America. JOURNAL OF CLINICAL MICROBIOLOGY, 55(2), 645-648. doi:10.1128/JCM.02162-16

  • Urquhart, E. A., Jones, S. H., Yu, J. W., Schuster, B. M., Marcinkiewicz, A. L., Whistler, C. A., & Cooper, V. S. (2016). Environmental Conditions Associated with Elevated Vibrio parahaemolyticus Concentrations in Great Bay Estuary, New Hampshire. PLOS ONE, 11(5). doi:10.1371/journal.pone.0155018

  • Heath-Heckman, E. A. C., Peyer, S. M., Whistler, C. A., Apicella, M. A., Goldman, W. E., & McFall-Ngai, M. J. (2013). Bacterial Bioluminescence Regulates Expression of a Host Cryptochrome Gene in the Squid-Vibrio Symbiosis. MBIO, 4(2). doi:10.1128/mBio.00167-13

  • Mahoney, J. C., Gerding, M. J., Jones, S. H., & Whistler, C. A. (2010). Comparison of the Pathogenic Potentials of Environmental and Clinical Vibrio parahaemolyticus Strains Indicates a Role for Temperature Regulation in Virulence. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 76(22), 7459-7465. doi:10.1128/AEM.01450-10

  • Whistler, C. A., & Pierson, L. S. (2003). Repression of phenazine antibiotic production in Pseudomonas aureofaciens strain 30-84 by RpeA. JOURNAL OF BACTERIOLOGY, 185(13), 3718-3725. doi:10.1128/JB.185.13.3718-3725.2003

  • Whistler, C. A., Stockwell, V. O., & Loper, J. E. (2000). Lon protease influences antibiotic production and UV tolerance of Pseudomonas fluorescens Pf-5. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 66(7), 2718-2725. doi:10.1128/AEM.66.7.2718-2725.2000

  • Whistler, C. A., Corbell, N. A., Sarniguet, A., Ream, W., & Loper, J. E. (1998). The two-component regulators GacS and GacA influence accumulation of the stationary-phase sigma factor sigma(S) and the stress response in Pseudomonas fluorescens Pf-5. JOURNAL OF BACTERIOLOGY, 180(24), 6635-6641. doi:10.1128/JB.180.24.6635-6641.1998

  • Most Cited Publications