On the energetics of differentiation. V. Comparison of the rates of development and of oxygen consumption of tight membrane and normal echinoderm eggs

✍ Scribed by Tyler, Albert

• Publisher: John Wiley and Sons
• Year: 1937
• Tongue: English
• Weight: 579 KB
• Volume: 76
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1400760304

✦ Synopsis

It is shown in these experiments that thick-walled embryos arising from tight membrane eggs develop more slowly than do normal embryos. The rate of oxygen consumption is, however, the same in both.

THEORETICAL PART

Embryos from isolated half-blastomeres of the sea urchin develop more slowly than normal. Those from isolated quarter-blastomeres develop still more slowly. On the other hand, giant embryos produced by fusion of two fertilized eggs develop more rapidly than do the normal embryos. These differences in rates of development are interpreted (Tyler, '33, '35) as due to differences in the energy required f o r the differentiation processes in these various embryos. The rate a t which energy is supplied, as measured by the rate of oxygen consumption, was shown to be the same per unit mass for the half-embryos as for the normals. The half-embryos requiring more energy to reach the same stage of development therefore develop more slowly. For the quarter-embryos and giant embryos no oxygen consumption measurements were made, but it is assumed that they too would show the same rate per. unit mass as the normals. It is from dimensional reasoning 395