. The beginnings of embryonic development : A symposium organized by the Section on Zoological Sciences of the American Association for the Advancement of Science, cosponsored by the American Society of Zoologists and the Association of Southeastern Biologists, and presented at the Atlanta meeting, December 27, 1955. Embryology. A. MONROY 171 respect to heat denaturation. To distinguish between denatured and nondenatured proteins the sohibihty in an acid buffer of high molarity was used. This buffer has been shown to induce precipitation of denatured lactoglobuRn and serum albumin, whereas whe
. The beginnings of embryonic development : A symposium organized by the Section on Zoological Sciences of the American Association for the Advancement of Science, cosponsored by the American Society of Zoologists and the Association of Southeastern Biologists, and presented at the Atlanta meeting, December 27, 1955. Embryology. A. MONROY 171 respect to heat denaturation. To distinguish between denatured and nondenatured proteins the sohibihty in an acid buffer of high molarity was used. This buffer has been shown to induce precipitation of denatured lactoglobuRn and serum albumin, whereas when they are in the native condition these proteins stay in solution (Christensen, 1952). In the case of the sea urchin egg extracts, a large proportion of the extracted proteins is precipi- tated by the buffer without any previous denaturing treatment, and the amount of precipitate is greater in the case of the un- fertilized eggs. Although this result does not allow one to draw any conclusion as to the condition that makes such proteins sus- ceptible to the salt buffer, it is nevertheless indicative of a differ-. Fig. 1. Electrophoretic patterns after trypsin digestion of the fraction precipitated at 50% saturation of ammonium sulfate from an extract of un- fertilized (solid line) and fertilized (dotted line) eggs. (Redrawn from an experiment of D'Amelio.) ence between the proteins of the unfertilized and of the newly fertilized eggs. A difference between the two is also shown by mere inspection of the precipitate which is flocculent and rapidly settling in the former, whereas in the latter it is finely dispersed, takes some time to appear, and settles only very slowly. The total amount of precipitable proteins upon heating between 50° and 60° C. followed by addition of the buffer is significantly greater in the extracts of unfertilized than in those of fertilized eggs. The same result has been obtained with the fraction pre- cipitated by 50% saturation with ammonium sulfate
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Keywords: ., bookcentury1900, bookpublisherwashington, booksubjectembryology
