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Full-Text Articles in Organismal Biological Physiology
Evidence Of A Rudimentary Colon In Leucoraja Erinacea, Alyssa M. Simeone
Evidence Of A Rudimentary Colon In Leucoraja Erinacea, Alyssa M. Simeone
Honors Theses
During the transition of animals from water onto land, the colon is believed to have evolved as an essential water-absorbing organ in terrestrial vertebrates to prevent desiccation. The class Chondrichthyes, comprised of sharks, rays, and skates, are isotonic to their marine environment, and thus do not require a functional colon. The Chondrichthyes are an excellent organism for developmental and physiological studies in evolutionary context because they have undergone little evolutionary change since their appearance 450 million years ago. Previous histochemical studies demonstrate potential water absorbing properties in the digestive tract of the little skate, Leucoraja erinacea (Theodosiou et al., 2007). …
A Messenger Molecule Governs Interdependency In An Evolved Pseudomonas Aeruginosa Biofilm Community, Thomas Macelliott Johnson
A Messenger Molecule Governs Interdependency In An Evolved Pseudomonas Aeruginosa Biofilm Community, Thomas Macelliott Johnson
Honors Theses and Capstones
Biofilm populations are known to harbor great diversity, but the importance of this diversity is not fully understood. A likely contributor to this variation is the second messenger molecule cyclic-di-GMP: low levels associate with a planktonic lifestyle while high levels favor biofilm formation. In ongoing studies of an evolving biofilm population of Pseudomonas aeruginosa (PA), we observed extensive ecological diversification that may relate to this lifestyle switch. In PA, the gene bifA encodes a phosphodiesterase that is known to degrade cyclic-di-GMP and reduce biofilm. This gene was cloned onto a plasmid under control of an inducible promoter and the plasmid …