INDICATOR GRADIENT PATTERNS IN OÖCYTES AND EARLY DEVELOPMENTAL STAGES OF ECHINODERMS: A REEXAMINATION

¹ School of Biological Sciences, Stanford University, Stanford, Calif., and Hopkins Marine Laboratory, Pacific Grove, Calif.

1. With progress in the use of redox indicators, it has been found that slight gradient differentials become more distinctly visible by intracellular oxidation of redox dyes, reduced by essentially non-toxic sodium hydrosulphite, and of low concentrations of indophenol reagents than in reduction of oxidized dyes. Staining by oxidized dyes preceding reduction may itself decrease slight differentials.

2. By means of intracellular oxidation of reduced dyes and indophenol reagents a gradient pattern has been rendered directly visible from early oöcyte to larval stages. The evidence indicates that the gradient of the early oöcyte becomes the polar gradient of the egg and embryo. In early oöcyte stages, position of the nucleus varies, but as oöcyte growth progresses it comes to lie near the pole of most rapid intracellular oxidation, the polar bodies form there and this becomes the apical (animal) pole of egg and embryo.

3. The ventrodorsal gradient pattern becomes visible in the gastrula, perhaps in the late blastula, but is undoubtedly present earlier, probably with a differential too slight to be visible or in another physiological condition. Other gradients appear in the further course of development.

4. Experiments of Pease on determination of ventrodorsality in Dendraster by gradients of inhibitory agents are discussed in relation to redox gradient pattern.

This article has been cited by other articles:

				P. B. Weisz Diffusion and Chemical Transformation: An interdisciplinary excursion Science, February 2, 1973; 179(4072): 433 - 440. [PDF]