UW Microbiology

The Erasmus virus resets 207 genes in lung cells to hamper the cells' ability to launch an antiviral reaction. Available drugs might correct this sabotage.

Congratulations to Alistair Russell, Microbiology Graduate Student in the Joseph Mougous Lab, and recipient of the very prestigious DeKarman Fellowship from the Josephine DeKarman Fellowship Trust. This competitive fellowship recognizes students whose scholastic achievements reflect very high standards, as defined by the fellowship’s founder, Theodore von Karman. Less than 3% of the applicants meet the qualifications to receive this generous fellowship.

Congratulations to Seemay Chou, Postdoctoral Fellow in the Joseph Mougous Lab, who received a career development grant from the American Society for Microbiology (ASM). This grant is awarded to postdoctoral women with outstanding scientific accomplishments and potential for significant research in the area of Microbiology, and only three grants are awarded each year.

Congratulations to Mary Lidstrom, Professor of Microbiology and Chemical Engineering on her recent election to the National Academy of Sciences.

Congratulations to Houra Merrikh and Evgeni Sokurenko whose groundbreaking research on gene evolution is featured in UW Today:

Congratulations to Matthew R. Parsek, Professor of Microbiology, who has been elected to Fellowship in the American Academy of Microbiologists, a tribute and recognition of excellence in science.

Fellows of the AAM are elected annually through a highly selective, peer-review process, based on their records of scientific achievement and original contributions that have advanced microbiology.

Tuesday, May 28, 2013, T-639 Health Sciences Building, 4:00 PM

Sarkis Mazmanian, Ph.D.
Professor, Division of Biology
California Institute of Technology

Learning to tolerate our microbial self

Mammals harbor a complex gut microbiota, comprised of microorganisms that provide nutritional, metabolic and immunologic benefits during colonization. Despite recent advances in sequence-based microbiome profiling, virtually nothing is known about the molecular processes employed by symbiotic bacteria to permanently colonize animals. Although the gastrointestinal tract can harbor a tremendous density and diversity of microbes, we find that mono-association of germ-free mice by a single Bacteroides species inhibits colonization by identical, but not closely related, species. To identify bacterial mechanisms for species-specific saturable colonization, we devised an in vivo genetic screen and discovered a novel operon that is highly conserved among the intestinal Bacteroides, one of the most prominent gut bacterial genera of humans. We named this genetic locus the commensal colonization factors (ccf), which consist of transcriptional regulatory genes that control expression of an outer membrane protein complex. Deletion of the ccf genes in the model symbiont, Bacteroides fragilis, results in colonization defects in both germ-free and complex microbiota harboring mice. The ccf genes are preferentially expressed at the mucosal surface, but not in the intestinal lumen or in the laboratory culture, suggesting they mediate spatial association with host tissues. Indeed, bacterial mutants in this pathway are unable to occupy the colonic crypts of mice. Remarkably, the ability of B. fragilis to re-colonize the gut after antibiotic depletion or gastroenteritis requires the CCF system, suggesting the protected mucosal niche within intestinal crypts represents a reservoir for gut bacteria. These findings reveal that intestinal Bacteroides have evolved species-specific molecular interactions with the host that mediate stable and resilient gut colonization. We propose that successful host-microbial symbiosis is promoted by bacterial 'founder' cells that re-populate the gut after environmental stress