Defense Date

7-24-2003

Graduation Date

Summer 2003

Availability

Immediate Access

Submission Type

thesis

Degree Name

MS

Department

Biological Sciences

School

Bayer School of Natural and Environmental Sciences

Committee Chair

Richard P. Elinson

Committee Member

John S. Doctor

Committee Member

Nancy Trun

Keywords

E. coqui, Gut development, Thyroid hormone

Abstract

Among the frogs there are two forms of development: biphasic and direct. Xenopus laevis, a biphasic developer, develops from an embryo into a tadpole, and then metamorphoses into an adult frog. Eleutherodactylus coqui is a direct developer, meaning that it lacks a tadpole stage. The embryo develops directly into the adult form. Comparing development between these two frogs provides insight on the evolution of these groups. I present an anatomical description of the gut development of E. coqui, and compare my findings to the development of X. laevis. E. coqui does not have a highly coiled gut like that of X. laevis tadpole, and the composition and gut size differs from X. laevis as well. In addition, I examined the proliferation pattern in the E. coqui gut by immunocytochemistry. The gut of X. laevis has a directional proliferation pattern during metamorphosis. The gut of E. coqui does not have this proliferation pattern. Instead, the anterior and posterior tubes have high levels of proliferation throughout development, and the other regions of the gut exhibit lower and variable levels of proliferation. I also examined the proliferation pattern of X. laevis tadpole intestines during metamorphosis, induced in pre-feeding tadpoles (NF 46/47) with exogenous thyroid hormone. Thyroid hormone induces precocious remodeling as shown by shortening of the intestine and proliferation in selective regions.

Format

PDF

Language

English

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