News

Undergraduate and Beckman Research Scholar Adriahna Blackburn took hope first prize for undergraduate posters at the recent ASM Missouri Valley Branch Regional Meeting held at Creighton University in Omaha, NE. She presented work about a repressor called PrtR that is involved in pyocin regulation in P. aeruginosa. This was her first poster presentation at a regional meeting, and we're so proud of her excellent performance right out of the gate!

https://www.facebook.com/photo?fbid=408766385308527&set=a.116805237837978

Senior PhD student Somalisa Pan and former postdoc Simon Underhill have teamed up yet again to publish work in collaboration with the Manjarrez Lab at OSU-CHS to showcase some of the biofilm and virulence phenotypes of strains that are mutant for glycerol and glucose utilization. From the Cabeen lab, former PhD student Chris Hamm and former undergraduate Dax Butler are also contributors. The paper is available in ASM's open-access mSphere journal at https://doi.org/10.1128/msphere.00786-23. Congratulations to all the authors!

Former undergraduate Sid Bush is the lead author on primarily undergraduate research from the lab—a collaboration among 8 current and former undergraduates and former grad student Chris Hamm. This team did a huge amount of work over the years to show that different strains of B. subtilis with different complements of RsbR paralogs in the stressosome display differing fitness in co-culture under different stress conditions. A primary finding of the paper is that RsbRA-only cells, whose sigma-B response resembles the wild type, outcompete other single-RsbR strains under ethanol stress but have a fitness deficit under NaCl stress, while the opposite is true of RsbRD-only cells. The paper is available in ASM's open-access mSphere journal at https://doi.org/10.1128/msphere.00719-23. An image from their paper also made the cover for that issue of mSphere! Congratulations to Sid, Shelby, Nick, Chris, Madeline, Sarah, Emily, AnaLisa, Nick, and Jake!

PhD candidate Somalisa Pan published a principal project of her PhD, investigating a putative lipase protein that she discovered in collaboration with the lab's first-ever undergraduate researcher, Julia Terrell, and characterized with the help of recently graduated undergraduate, Mary Erdmann. The protein, previously named PA14_04030 but renamed BipL (for biofilm-impacting phospholipase), was originally uncovered by Soma and Julia as restoring colony wrinkling to a smooth colony when the bipL gene was deleted. Subsequent experiments showed that BipL harbors a conserved lipase signature motif, and that mutation of the active-site Ser residue phenocopies the bipL deletion. Congratulations Soma, Mary, and Julia! The paper is available in ASM's open-access mSphere journal at https://doi.org/10.1128/msphere.00374-23.

PhD candidate Amal Yahya successfully defended her thesis on July 3, 2023 and now is Dr. Yahya! Dr. Yahya will return this summer to her native Saudi Arabia, where she will become an assistant professor near Riyadh and teach clinical technicians. We are so proud of how far she has come and will miss her presence in the lab.

Dr. Cabeen was promoted to Associate Professor with Tenure on July 1, 2023, together with his colleague Dr. Karen Wozniak down the hall. Congratulations!

Former postdoc Dr. Simon Underhill and PhD candidate Somalisa Pan published a big project in which they examined the nitrogen-related phosphotransfer system (Nitro-PTS) in P. aeruginosa in unprecedented detail. Mary Erdmann, a talented undergraduate working with Soma, was also a coauthor. The team showed that unphosphorylated PtsN, which was previously implicated in lowering biofilm formation, is not sufficient on its own to reduce biofilm formation. They also showed that PtsN can be phosphorylated by a different enzyme I, FruB, but only in the absence of PtsO. PtsP also appears to be able to directly phosphorylate PtsN. Finally, using transcriptomics, they discover new systems that appear to be regulated by the Nitro-PTS, including production of a siderophore (pyoverdine) and express of Type III secretion. Congratulations Simon, Soma, and Mary! The paper is available in the Journal of Bacteriology at https://doi.org/10.1128/jb.00453-22 (may require a journal subscription).

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.