My laboratory is interested in understanding the biology of the human pathogen Candida albicans. C. albicans is a yeast that grows in the human gastrointestinal tract and is usually harmless to humans. However, in some cases, Candida can cause localized infections in healthy individuals and even life-threatening systemic (bloodstream) infections in immunocompromised individuals. The focus of the laboratory is to understand how Candida acts as a pathogen in humans.

Research Description

My laboratory is focused on studying the newly identified sexual cycle of Candida albicans. There are a number of interesting aspects to mating in C. albicans, including the role of 'phenotypic switching', in which cells can reversibly switch their morphology between specialized forms called 'white' and 'opaque'. While white cells are more virulent in models of systemic infection, only opaque forms are competent to mate. We are currently investigating the idea that this unique adaptation has arisen to allow mating to occur in the hostile environment of the mammalian host.

A second unusual feature of the C. albicans sexual cycle is that while mating occurs efficiently, no meiotic pathway has been identified yet. Meiosis is a conserved process in which DNA replication is followed by two successive DNA divisions, effectively halving the DNA content in the cell. In its place, we have discovered that efficient non-meiotic chromosome loss can be induced in C. albicans, thereby completing a simple sexual cycle in the organism. Both the mechanism of chromosome loss and the role of the sexual cycle in infection of the host are under investigation. For example, one model we are presently testing is that the mixing of chromosomes during the mating cycle generates strains with increased genetic diversity. These new strains could contribute directly to virulence by generating bursts of genetic diversity that aid in fitness in infection.

Awards

Burroughs Wellcome Fund Investigator in Infectious Disease, 2008-2013
Human Frontier Science Program Fellow, 1997-1998
Damon Runyon-Walter Winchell Foundation Fellow, 1996
Ph.D., Imperial College, London, 1995
M.A., Cambridge University, 1992
1st Class Honors Degree, Natural Sciences, B.A., Cambridge University, 1991

Affiliations

American Society of Microbiology
American Society of Cell Biology

Funded Research

Current Funding
7/1/08 - 6/30/15, Burroughs Wellcome Fund
Phenotypic Variation and Host Adaptation by the Human Fungal Pathogen Candida albicans.

7/1/09 - 6/30/11, NIH
Phenotypic Switching in Candida albicans and its Role in Pathogenesis.

3/1/08 – 2/28/09, Brown Seed Grant
"Molecular Analysis of a Bistable Switch in the Pathogen Candida albicans".

Completed Funding
1/1/08 – 12/31-08, Center for AIDS Research Developmental Award
"Phenotypic switching in the opportunistic pathogen Candida albicans".

2/1/07 – 1/31/08, Richard B. Salomon Faculty Research Award.
"Genetic and epigenetic variation in the human pathogen Candida albicans".

01/01/2006 - 12/31/2006, Rhode Island Foundation Grant.
"How does the mating cycle of Candida albicans contribute to its success as a human pathogen".

Teaching Experience

BI0510 Introduction to Microbiology
This course introduces undergraduate students to the world of microbes, including bacteria, viruses, and fungi. Students learn about the basic molecular properties of microbes, as well as their role in everyday life.

Courses Taught

• Introduction to Microbiology (BIO510)

View My Full Publication List in pdf format

Selected Publications

• Alby, K. and Bennett, R.J. (2009) Stress-Induced Phenotypic Switching in Candida albicans. Mol. Biol. Cell. 20: 3178-91(2009)
• Bennett, R.J. (2009) A Candida-based view of fungal sex and pathogenesis. Genome Biology 10:230(2009)
• Alby, K., Schaefer, D., and Bennett, R.J. (2009) Homothallic and Heterothallic mating in the opportunistic pathogen Candida albicans. Nature 460:890-893.(2009)
• Alby, K. and Bennett, R.J. (2009) To Switch or Not to Switch? Communicative and Integrative Biology. In press.(2009)
• Forche, A., Schaefer, D., Alby, K., Johnson, A.D., Berman, J. and Bennett, R.J. (2008) The Parasexual Cycle in Candida albicans Provides an Alternative Pathway to Meiosis for the Formation of Recombinant Strains. PLoS Biology. 6: e110.(2008)
• Sherwood, R.K., and Bennett R.J. (2008) The Microtubule Motor Protein Kar3 is Required for Normal Mitotic Division and Morphogenesis in Candida albicans. Eukaryotic Cell. 7: 1460-1474.(2008)
• Schaefer, D, Cote, P, Whiteway, M, and Bennett, RJ (2007) Barrier Activity in Candida albicans Mediates Pheromone Degradation and Promotes Mating. Eukaryotic Cell. 6: 907-918.(2007)
• Bennett, RJ, and Johnson, AD (2006) The role of nutrient regulation and the Gpa2 protein in the mating pheromone response of C. albicans. Mol. Microbiol. 62: 100-119.(2006)
• Bennett RJ, Miller MG, Chua PR, Maxon ME, Johnson AD. Nuclear fusion occurs during mating in Candida albicans and is dependent on the KAR3 gene. Mol Microbiol. 2005 Feb;55(4):1046-59.(2005)
• Bennett RJ, Johnson AD, Mating in Candida albicans and the Search for a Sexual Cycle. Annu Rev Microbiol. 2005 May 23.(2005)
• Bennett RJ, Keck JL. Structure and function of RecQ DNA helicases.Crit Rev Biochem Mol Biol. 2004 Mar-Apr;39(2):79-97. Review.(2004)
• Bennett RJ, Uhl MA, Miller MG, Johnson AD. Identification and characterization of a Candida albicans mating pheromone. Mol Cell Biol. 2003 Nov;23(22):8189-201.(2003)