Linda E. Hyman, Ph.D.

HymanProfessor of Microbiology
Associate Provost, Division of Graduate Medical Sciences
72 East Concord Street
Office: L317; 617-638-5320
lhyman@bu.edu

B.S.     State University of New York
M.S.    Brandeis University
Ph.D.   Brandeis University

The Hyman lab studies the response of Saccharomyces cerevisiae and Candida albicans to simulated microgravity. Modeling the microgravity environment, using rotating suspension culture bioreactors, allows investigation of eukaryotic cellular responses in a ground-based model and provides insights into the impact of space flight on cellular physiology.  

We have demonstrated that simulated microgravity induces morphologic changes and differential expression of several groups of yeast genes, including those related to morphogenic (morphological) transformation, polarity determination, and the unique environmental stress of microgravity.  The net result of altered polarity is a disrupted budding pattern in Saccharomyces cerevisiae and filamentation in Candida albicans consistent with increased pathogenicity.   

S. cerevisiae is an excellent model organism to examine fundamental aspects of cell biology common to eukaryotic systems, such as polarity determination.  C. albicans, being an opportunistic human pathogen, allows the investigation of effect of microgravity its pathogenicity.

The overall objective of a newly funded NASA grant (7/09) is to examine the hypothesis that cells exposed to microgravity undergo phenotypic and genotypic changes that alter polarity determination.

In Saccharomyces cerevisiae localization and expression levels of selected proteins will be evaluated in response to simulated microgravity using green fluorescence protein fusion constructs and mutational analysis of selected genes.  In addition, signal transduction pathways involved in sensing mechanoreception driving these responses will be addressed. 

Ultimately, the propensity for increased biofilm formation and virulence will be evaluated in Candida albicans subjected to simulated microgravity.

Given the flexible requirements for yeast growth and the availability of molecular tools in the yeast system, these ground-based studies can be readily adapted to space-flight testing.

Recent Publications

1.         Altenburg, SD, SM Nielsen-Preiss and LE Hyman.  2008.  Increased filamentous growth of Candida albicans in simulated microgravity. Genomics Proteomics Bioinformatics  6(1):42-50.

2.         Sheehan, KB, K. McInnerney, B. Purevdorj-Gage, SD Altenburg and LE Hyman.  2007.  Yeast genomic expression patterns in response to low-shear modeled microgravity. BMC Genomics. 8(3), 2007.

3.         Purevdorj-Gage, B, ME Orr, P Stoodley, KB Sheehan and LE Hyman.  2007.  The role of FLO11 in Saccharomyces cerevisiae biofilm development in a laboratory based flow-cell system. FEMS Yeast Res. 7(3):372-379.

4.         Purevdorj-Gage, B, KB Sheehan and LE Hyman.  2006.  Effects of low-shear modeled microgravity on cell function, gene expression, and phenotype in Saccharomyces cerevisiae. Appl. Environ. Microbiol. 72(7):4569-4575.

 

 

c-albicans

 

            Picture of C albicans exposed to 50uM PD98059 for 4 hours at 37°C

     

  image002

 

To mimic some of the elements of microgravity on the ground we utilize a rotating wall culture vessel, a High Aspect Ratio Vessel (HARV).  The rotation of the vessel ensures the media suspended cells do not settle over time, but rather are in a continuous state of free-fall which is in effect “functional weightlessness” (Klaus, et al., 2001). 

 

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Primary teaching affiliate
of BU School of Medicine