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Brian Ahmer, PhD

Ahmer.jpg

Associate Professor, Microbial Infection and Immunity

Contact information:​
710 Biomedical Research Tower (BRT)
460 W 12th Ave, Columbus OH 43210
Phone: (614) 292-1919​
ahmer.1@osu.edu

Publications

Research Interests

We are studying how Salmonella thrives in the host environment. We are currently focusing on three projects:

1. Detection of other microbes by Salmonella.
Some bacteria use pheromones (N-acylhomoserine lactones or AHLs) to determine their population density. Salmonella does not make AHLs but it can detect the AHLs produced by other bacteria. We hypothesized that Salmonella would detect AHLs made by the normal intestinal flora and use this information to adjust its gene expression accordingly. Surprisingly, we discovered that the normal gut flora does not make AHLs and instead, Salmonella is detecting the AHL production of other pathogens in the gut. Salmonella can detect the AHL production of Aeromonas hydrophila in turtles and Yersinia enterocolitica in mice. We are characterizing this same AHL detection system in E. coli, Klebsiella, Enterobacter and other closely related organisms.

2. Coordination of metabolism and virulence by SirA and CsrA.
Throughout the gamma-proteobacteria a two-component response regulatory system determines the metabolic state of the cell and regulates gene expression accordingly. BarA is the histidine sensor kinase that detects the metabolic signal (probably acetate which peaks in late exponential phase) and SirA is the transcription factor that is phosphorylated and activated by BarA. A second system is the Carbon Storage Regulatory system that consists of an RNA binding protein that binds and prevents translation of particular mRNAs. Interestingly, SirA activates the expression of two small RNAs that inhibit CsrA activity. Currently, we are studying when SirA and CsrA become active during various stages of infection.

3. Characterization of fructose-asparagine metabolism.
We recently determined that Salmonella relies heavily on a single nutrient during growth in the inflamed intestine, fructose-asparagine. We are characterizing the enzymology and regulation of this system as well as developing novel therapeutic approaches that target this system.


 

Laboratory:  750 Biomedical Research Tower, 614-292-7666

Personnel

Sierra Cydrus

Undergraduate

cydrus.5@osu.edu

​Tyler Ritchie ​Undergraduate ritchie.126@osu.edu

Anice Sabag-Daigle

Research Scientist

sabag-daigle.1@osu.edu​

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