How do fish cope with changes in water temperature and salinity when they are literally bathed in those stressors? That question was answered just a few years ago by researchers in the Dept. of Human Nutrition, Food and Animal Sciences, who discovered that fish mediate heat stress and salinity acclimation via the hormone prolactin.
Continuing that research, HNFAS students under mentor Andre Seale have found multiple transcription factors that are sensitive to ambient solute concentration. These factors control the gene that encodes for prolactin, and respond to changes in salinity and temperature encountered by the fish.
Gene switches sensitivity
“Transcription factors are molecules that turn genes on and off by binding to DNA,” explains grad student Tharindu Malintha, who recently defended his PhD dissertation with “Environmentally Sensitive Transcription Factors in the Prolactin Cell, Gill and Kidney of Mozambique Tilapia (Oreochromis mossambicus).”
Changes in temperature, he adds, can activate or inhibit these same transcription factors and characterize the molecular pathways activated in gills and kidney when fish are in different salinities.
How tight?
Meanwhile, with support from a UROP award, HNFAS undergrad Ke Cao has been working on a project to show how tight-junction proteins help fish cope with change. Tight-junction proteins play a key role in maintaining structural integrity between cells. When fish are challenged with rapidly changing salinities, these proteins act to prevent excessive water movement across the gill.
Cao recently presented at the 46th annual Albert L. Tester Memorial Symposium and the UROP undergraduate showcase.
"I’m extremely proud of these two young scientists,” says Andre, who is the 2023 recipient of the Ka Pouhana Dean’s Award for Excellence in Mentoring. “Through their hard work and dedication, they produced impactful research while making speedy progress toward their personal and professional development."
Read Malintha’s and Andre’s full article, “Osmosensitive transcription factors in the prolactin cell of a euryhaline teleost,” which appears in a recent Comparative Biochemistry and Physiology.