| For my dissertation research I have two main projects: | |
| 1.) An analysis of the digestive physiology of herbivorous and carnivorous minnows. I am comparing sister genera of North American minnows that display different feeding strategies: Campostoma are herbivorous, whereas Nocomis are primarily carnivorous. By examining the digestive physiology of the eleven taxa comprising these adjacent clades, I plan to elucidate what physiological characters arose in Campostoma affording them the ability to consume and digest algal material. Thus far, data show that Campostoma have gut length to body length ratios [relative gut length (RGL) for short] four to five times greater than those seen in Nocomis. Campostoma exhibit high amylase activities, whereas Nocomis exhibit higher trypsin and lipase activities. Km analyses also indicate that these two genera may be expressing different trypsin isoforms. Campostoma appear to be fermenting algal structural polysaccharides, as these fishes have approximately 12 mM short chained fatty acids (SCFA) in their digestive tracts. Nocomis have very low (<5 mM), many times undetectable, SCFA levels in their guts. These data are still being generated. Expect a manuscript on these fishes in the near future. | |
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2.) An analysis of the digestive capabilities in xylophagus (wood-eating) loricariid
catfishes of the genera Panaque and Hypostomus. I am very intrigued by these
xylophagus catfishes and am asking the question: What does it take to eat wood?
I am currently investigating whether an algivorous loricariid, Pterygoplichthys
disjunctivus, can assimilate wood. P. disjunctivus has been introduced to local
waterways in Florida, and I captured my experimental animals from a spring near
Apopka, FL. These data are just beginning to be generated so stay tuned to find
out whether wood-eating is just a myth, or an actual dietary strategy.
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| Below is a link to a video of a Panaque nocturnus gut still undergoing peristalsis after being removed from the animal: http://zoology.ufl.edu/PERSONAL/grad/dgerman/images/Peristalsis1.AVI |
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