Arctic | Mammals
Into the belly of the beast: Cultivation of bowhead whale gastrointestinal microorganisms and insights into prey lipid metabolism Presenter: Mallory Kastner , mallorykastner2@gmail.com, Carolyn Miller , cmiller@whoi.edu, Woods Hole Oceanographic Institution Benjamin Van Mooy , bvanmooy@whoi.edu, Woods Hole Oceanographic Institution Helen Fredricks , hfredricks@whoi.edu, Woods Hole Oceanographic Institution Lara Horstmann , lara.horstmann@alaska.edu, University of Alaska Fairbanks Raphaela Stimmelmayr , raphaela.stimmelmayr@north-slope.org, North Slope Borough, Department of Wildlife Management Amy Apprill , aapprill@whoi.edu, Woods Hole Oceanographic Institution Baleen whales, such as the Arctic bowhead whale ( Balaena mysticetus ), have a lipid-rich diet through immense consumption of small-bodied prey (e.g., copepods). Copepods are rich in wax ester lipids, contributing at times to over 80% of the bowhead whale lipid intake. This is a unique nutritional adaptation, as terrestrial mammals do not efficiently metabolize wax esters. Previously, we demonstrated a significant decrease in wax ester abundance in the bowhead whale jejunum (mid-small intestine), which was correlated with a shift in dominant gut bacterial communities. This suggested that the gut microbiome may play a role in wax ester break down, yet no wax ester degrading microbes have been characterized. Using samples collected during annual fall Iñupiat subsistence hunts in Utqiaġvik, AK, our research aimed to isolate microorganisms residing in the bowhead whale gut, including potentially wax ester degrading bacteria. Microbial colonies were grown anaerobically on media containing copepod wax esters, resulting in 39 pure microbial strains. Each isolate is taxonomically identified through sequencing. Additionally, these microbes’ wax ester lipid degrading ability will be assessed using gas chromatography mass spectrometry to quantify the breakdown of wax esters after incubation at bowhead whale body temperature (33.8°C). Our study successfully cultivated bacteria from the gastrointestinal tract of this important Arctic whale, and may reveal novel wax ester degrading bacteria and a unique host-microbe association in mammalian digestion. Studying the role of gut microbes in baleen whale digestion is key in understanding the physiology and health of these large marine mammals.
Alaska Marine Science Symposium 2023 278
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