John F. Rawls

Please share w/ interested colleagues this new EMBO Course in Bath UK (6-18 July 2026) “Computational & experimental microbiomics”: lnkd.in/e7EGH4RG

The course includes experimental emphasis on zebrafish host-microbiome interaction + general microbiomics skills. Register is 11 May #EMBOMicrobiomics

Happy International Day of Women & Girls in Science! Today & everyday I am grateful for the opportunity to work alongside & learn from this talented group of women scientists. Funded by grants from the NIH, this team is working to understand how the gut microbiome affects our digestive health.

Our EMBO workshop is now live. Visit us in Bath this summer for a two week workshop designed to help you study host-microbe interactions in the zebrafish, and develop the bioinformatics skills needed to analyse the complex data sets that arise from microbiomic studies.

Enteroendocrine cell subtypes in zebrafish: A zebrafish larva at 6 days postfertilization expressing transgenic reporters neurod1:TagRFP, neurogenin3:QF2, and QUAS:GFP. neurod1:TagRFP labels the pancreatic islet and all enteroendocrine cells in the gut and is shown in magenta. The combination of neurogenin3:QF2 and QUAS:GFP reporters labels a subset of enteroendocrine cells in the gut and is shown in cyan. Overlapping signal appears white. Image credit: Margaret Morash.

Enteroendocrine cells (EECs) in the #gut #epithelium secrete diverse hormones that regulate digestion, energy use & behavior. @jfrawls.bsky.social &co identify EEC subtypes & #hormone profiles in #zebrafish, and explore their lineage relationships @plosbiology.org 🧪 plos.io/49iZKWC

Identification of intestinal enteroendocrine cell subtypes and their associated hormones in zebrafish Enteroendocrine cells (EECs) in the gut epithelium secrete diverse hormones that regulate digestion, energy use, and behavior. This study identifies EEC subtypes and their hormone profiles in zebrafis...

Two new articles from our lab!!

Davis et al identified epithelial transcription factor ELF3 as a key mediator of host-microbiota interaction in zebrafish tinyurl.com/pkavnxdp

Morash et al revealed enteroendocrine cell subtypes in zebrafish & catalogued their peptide hormones tinyurl.com/bdzbm2xm

Part 7 & End of Chapter: While waiting for export permits, we explored the Kathmandu Valley—alive with Buddhist & Hindu traditions, temples at every turn, chaotic traffic, hills filled with with monasteries, & endless momos. Fieldwork now complete, the analysis phase begins. Thanks for following!

YouTube video by John Rawls Zebrafish in the wild

Part 6: For decades, the zebrafish has helped scientists unlock the mysteries of genetics, development, & disease. But the fish that power most discoveries have spent generations inside lab tanks. This video captures footage of zebrafish in their natural environment in Nepal.
youtu.be/cCZhZpPALqw

Part 5: Amid the fieldwork & meetings, this trip also brought our U.S. & Nepali teams closer together. The visit happened to overlap with the Tihar festival, giving us time to see the celebrations firsthand & to share meals & conversations that connected the work to the culture & people around it.

Part 4: Our fieldwork focused on wild zebrafish, but in our downtime we couldn’t resist meeting some of Nepal’s other remarkable fauna. A highlight for me was seeing the critically endangered gharial crocodile up close at Chitwan’s Gharial Breeding Center.

Part 3: Agriculture & Forestry Univ. (AFU) was an outstanding partner & hub for this study. Their faculty generously shared lab space, equipment, & expertise essential to this work. We were especially impressed by the AFU students, whose curiosity & initiative energized the project. Dhanyabaad, AFU!

Yes! Detailed water chemistry data was collected at each site.

From Chitwan district of Nepal, but yes! I’ll follow up by DM.

Part 2: With expert guidance from our AFU partners, we explored Chitwan’s maze of streams, canals, and wetlands. Using a range of capture methods, we found zebrafish thriving in many locations. Stay tuned for movies!

No, but I’ve heard this is the best time of year to be in Nepal.

... Our trip began with a meeting with Nepal's Minister for Education, Science and Technology, Mahabir Pun, in Kathmandu. Then we headed down to Chitwan District to get started on our work.

Part 1: The last couple of weeks I've had the pleasure of working with a team of scientists from Duke University, University of Oregon, and Agriculture and Forestry University (AFU) in Nepal to study the biology of zebrafish in their natural habitat. ...

Another RawlsLab retreat is in the books! Activities included centering our core values & skill development goals, science communication, a postapocalyptic scavenger hunt, & enjoying the NC summer. Now more than ever, I’m deeply grateful to work alongside this team of talented & intrepid scientists.

Call for 20 Assistant Professor positions Karolinska Institutet is a world-leading medical university with a long and proud history of ground-breaking research. We are now recruiting outstanding early-career researchers with particularly exce...

Karolinska is looking for 20 (!!) assistant professors and offering 6 year appointments with ~1M USD startup packages.

ki.se/en/about-ki/...

Congratulations to Briana Davis and Maggie Morash on their successful PhD thesis defenses in the Duke University Molecular Genetics and Microbiology Program!

Happy International Women’s Day! Today and everyday I am grateful for the opportunity to work alongside and learn from this talented group of women scientists. Funded by grants from the NIH, this team is working to understand how the gut microbiome affects our digestive and metabolic health.