News

PhD candidate Chris Hamm successfully defended his thesis on April 12, 2023 and now is Dr. Hamm! The good doctor has a great postdoc lined up at the University of Alabama-Birmingham, where he has also been awarded a competitive, NIH-funded MERIT fellowship that will also give him the opportunity to design a course and get teaching experience in parallel with his research. Chris is the first PhD to graduate from the Cabeen lab--we are so proud of you, Chris! He will begin his postdoc in July 2023.

PhD candidate Amal Yahya combined a huge amout of genetic work and phenotypic assays to explore new modes of biofilm regulation in P. aeruginosa. She and her undergraduate mentees Sophie and William showed that a number of genes that were differentially regulated in a deletion of 16550 (which shows decreased biofilm formation) largely do not impact biofilm formation but do impact motility. She also unexpectedly uncovered RecA as a biofilm-impacting gene and showed that both functions of RecA (SOS activation and recombination) appear important for wild-type biofilm levels. This work is published in Microbiollogy Spectrum from ASM and is available in open-access online at https://doi.org/10.1128/spectrum.03774-22.

Dr. Cabeen took home the 2022 College of Arts and Sciences Junior Faculty Award for Scholarly Excellence in the Sciences subdivision. Each year, one award is given to junior faculty (between years 3 and 7) in each of the three subdivisions of CAS: Arts/Humanities, Social/Behavioral Sciences, and Sciences. The award requires off-campus peer references and includes a plaque and cash award. Congratulations Dr. Cabeen!

PhD candidate Chris Hamm brings a huge amount of microfluidics-based experimental work to fruition in a new publication about how different RsbR proteins influence the sigma-B response mediated by the stressosome in different stressors. He shows that RsbRA always shows a transient response, irrespective of stressor identity, but that other RsbR paralogs show different responses to different stressors. Hybrid fusion proteins show that both halves of RsbRA are required for its characteristic transient response. He was assisted in this work by undergraduate Dax Butler. Their work is in press at mBio as of November 2022. Congratulations, gentlemen!

Yes, E. coli and P. aeruginosa are both gamma-proteobacteria. But don't make the mistake of thinking that their metabolic preferences are the same. E. coli loves glucose, but P. aeruginosa would rather eat citrate-cycle intermediates like citrate and aconitate. Despite this preference, little has been known about the uptake mechanisms. New work by Dr. Simon Underhill revises the current model for citrate utilization by P. aeruginosa, showing the importance of the putative TctCBA transporter and identifying new and redundant citrate transporters. His work is in press at Journal of Bacteriology. 

Recent graduates Nina Baggett and Adam Bronson are co-first authors on new work examining the differences between the absence of the XerC recombinase and the loss of recombinase function (via mutation or drug treatments) with respect to the basis for pyocin overproduction. Their work shows that only deletion of, and not inactivation of, XerC induces non-canonical pyocin expression. Moreover, known peptide inhibitors of bacterial recombinases do not induce pyocin expression. Their work is published in Miicrobiology Spectrum.

PhD candidate Rabi Khadka was a consistent winner in spring 2022! He was first selected for the departmental Ed and Mary Grula Graduate Fellowship. He followed up that win by being selected BOTH as the 2022 Outstanding Graduate Mentor and as the 2022 TA of the Year. These awards highlight Rabi's mentorship and teaching skills as well as his intellect and drive. You make us proud, Rabi!

At the Microbiology and Molecular Genetics Symposium held April 15, members of the Cabeen lab took home several presentation awards. PhD student Amal Yahya won 2nd place for her oral presentation, "Impact of RecA Functions on Pseudomonas aeruginosa Biofilm Suppression". PhD student Somalisa Pan and postdoc Simon Underhill shared a 2nd place award for their poster, "Characterization of the Nitro-PTS in Pseudomonas aeruginosa". PhD student Rabi Khadka took 3rd for his poster, "Mechanistic Basis for Stress Sensing by the Bacillus subtilis Stressosome". Good showing, guys!

PhD candidate Amal Yahya took the top award, the Best Overall Presentation award, at the annual Oklahoma Center for Respiratory and Infectious Diseases (OCRID) Symposium held April 6. This award is given to the trainee who gives the top presentation at the entire symposium and comes with a substantial cash prize. Amal's talk was titled "Impact of RecA Functions on Pseudomonas aeruginosa Biofilm Suppression". Awesome job Amal!