Publication Date

1974

Document Type

Dissertation/Thesis

First Advisor

Prahlad, K. V.

Degree Name

M.S. (Master of Science)

Department

Department of Biological Sciences

LCSH

Embryology--Amphibians||Xenopus laevis||Frogs

Abstract

It has been long thought that Xencrus laevis embryos (stage 25-25) have low permeability to labelled direct precursors of macromolecules. To study synthetic activities in early amphibian embryos, several indirect methods have been used by other workers: incubation of intact embryos in ¹⁴CO₂ environment; uptake of nucleic acid and protein precursors by dissociated Xenopus cells; and micro-injection of embryos. We have shown that radioactive labelled precursors are taken up in amounts sufficient to study cellular biochemical events in intact normally developing embryos kept in modified Holtfretter's media maintained at a pH of 7.2. ¹⁴C-leucine is taken up by the embryo with Kₘ, of C.73 x 10⁻⁵M and a V[sub max] of 5.4 x 10⁻⁸ uM/min. The level of uptake is 0.05 ug leucine per embryo which is a significant percentage of the free leucine pool. Also using this method it can be demonstrated that amino acids and nucleic acid precursors are taken up by embryos and the jelly coat has a selective influence on such uptake. This study clearly demonstrates that unmodified, intact, normally developing Xenopus laevis embryos will take up and incorporate protein and nucleic acid precursors.

Comments

Includes bibliographical references.||Includes illustrations.

Extent

vi, 61 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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