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W. LaJean Chaffin, PhD
Department of Immunology and Molecular Microbiology
Email: W. LaJean Chaffin, PhD
W. LaJean Chaffin, Ph.D., is a Professor in the Department of Immunology and Molecular Microbiology at Texas Tech University Health Sciences Center, Lubbock. Texas. Dr. Chaffin graduated from The University of Texas at Austin in 1964 with a B.A. degree in Chemistry. She graduated Cum Laude and was elected to Phi Beta Kappa. As a graduate student, she trained under Dr. Robert Bock in the area of eycaryotic protein translation working primarily with the model yeast Saccharomyces cerevisiae. She received her Ph.D. in Biochemistry from the University of Wisconsin, Madison in 1972. Dr. Chaffin worked as a Postdoctoral Research Fellow under Dr. Harlyn O. Halvorson, the Director of the Rosenstiel Basic Medical Sciences Research Center at Brandeis University, Waltham, Massachusetts. She was the recipient of National Institutes of Health Postdoctoral Research Fellowship (1975-1976). During this time she continued to work with S. cerevisiae as well as beginning work with Candida albicans. She joined the faculty of Texas Christian University, Ft. Worth, Texas, as an Assistant Professor of Biology (1973-1975. 1976-1980). She spent one year as a Visiting Assistant Professor of Chemistry at Texas Tech University, Lubbock, Texas before joining the Department of Microbiology of the School of Medicine at Texas Tech University Health Sciences Center, Lubbock, Texas in 1981. She received promotion and tenure as an Associate Professor in 1992 and promotion to Professor in 1997. She served as the Interim Chair of the Department of Microbiology and Immunology 1998-2001. She subsequently served as Associate Vice-President for Research and Acting Associate Dean for Research and The Graduate School 2002-2003. She has served on several institutional committees including the Graduate Council for the Graduate School of Biomedical Sciences (1989-1998, 2008-present) and served as its Secretary, 1990-1992 and Chair 1992/1993 and 1994/1995. She currently is a member of the Core Curriculum and Course Evaluation Committees. For the School of Medicine she has served on several committee including the Admissions Committee 1985-2001, Grading and Promotions Committee (chair 1993/1994), Tenure and Promotions (member 2001-2009 and Chair 2006-2007). Dr. Chaffin has served on the Editorial Board of Infection and Immunity and is currently a member of the Editorial Board of Antimicrobial Agents and Chemotherapy and currently is an ad hoc reviewer for several journals. She served as permanent member of NIH AIDS-associated Opportunistic infections and Cancer Study Section as well current various ad hoc assignments. Dr. Chaffin is a member of the Genetics Society of America, Medical Mycological Society of the Americas, International Society for Human and Animal Mycology and the American Society of Microbiology. She was Chair-elect (1995-1996) and Chair (1996-1997) of Division F of the ASM. Dr. Chaffin was a co-organizer of the 1st ASM Conference on Candida and Candidiasis in 1987 and served as member of the Organizing Committee, Chair or co-Chair for for the 2nd and 7th Conferences. Dr. Chaffin’s research has been supported by awards from the North Atlantic Treaty Organization and the National Institutes of Health.
My research focuses on the dimorphic human commensal and opportunistic pathogen Candida albicans. This yeast is a component of the microbiota of skin, and oral, gastrointestinal, and vaginal mucosa. When normal defenses of these surfaces are compromised the organism can cause an infection such oral thrush. The organism can also form biofilms on these surfaces and on devices such as dentures, voice prostheses, and catheters. These biofilms may accelerate deterioration of the device or be a reservoir for infecting surrounding tissue. As a component of normal flora the organism is frequently found in biofilms and in the yeast form while at sites of infection the hyphal form is also usually present. Biofilms are communities of organisms growing on a surface and surrounded by extracellular matrix material. Organisms in biofilms have different properties than organisms growing alone. Among these properties is reduced susceptibility to drugs and host phagocytic cells. In in vitro biofilms both yeast and hyphal forms are present. The scanning confocal image shows a developing biofilm on the surface of denture acrylic. The shapes of the organism are maintained by the cell wall that protects the organism from various environmental insults and is the physical surface interacting with the host. Much of my research has involved the cell wall of the organism with emphasis on non-covalently attached proteins. Studies have identified and localized candidal adhesins for host extracellular matrix proteins. In the process we were among the first to identify proteins on the surface that also have a function inside the cell. Such proteins are sometimes called “moonlighting” proteins because of the dual function and location. We have been interested in how the proteins at the surface change when the organism grows in the yeast form, the hyphal form, or in a biofilm. Recently, we have begun a project whose ultimate goal is to understand the dynamics of maintaining a Candida population in the oral and vaginal cavities. These host environments differ including difference in pH. One potential component is the death of non-growing cells which is also called chronological aging. We are looking at the chronological aging of organisms grown at different pHs and asking whether the cells die by necrosis or apoptosis. We have observed that the pH at which the organisms grow does affect aging. Many of the cells kept in liquid culture for two weeks show evidence of both necrosis and apoptosis as shown in the fluorescent image.
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