The Extracellular Release of Echinochrome* by Herbert Shapiro

Echinochrome, the red coloring matter found in sea urchin eggs, is not uniformly dissolved in the cytoplasm, but is distributed in the form of granules, and may be associated in these formed elements with other cellular components. I t may exist, intracellularly at least, as a chromoprotein. That the echinochrome is not in solution in the unfertilized egg cell, but exists practically entirely in the form of these discrete particles, is evident through microscopic examination and from centrifuging experiments. Under the influence of centrifugal force, the echinochrome granules can be concentrated at one end of the cell where they are easily visible, and with still higher centrifugal force the colored part of the cell can be separated from the renminder (Harvey, 1941; Shapiro, 1935 a, 1939). Tyler (1939) has made a survey of some of the chemical and physiological studies on this substance. If the peristomial membrane of an urchin, whether male or female, be punctured with the point of scissors, and the coelomic (perivisceral) fluid poured into a vial, it is observed to have a deep reddish coloration. Examined microscopically, this is found to be a concentrated suspension of eleocytes, which also contain the echinochrome. In eggs freshly taken from the urchin together with coelomic fluid, the coloring of the supernatant fluid is due to the presence of these coelomic amebocytes. However, in some cases after the eggs have been allowed to settle out of the colored supernatant fluid, the eleocytes are nevertheless found there in but low concentration. I t is to be presumed then that the echinochrome has diffused out of the elaeocytes, or that part of the color may be due to the contact of the coelomic fluid with the test. I t was very likely with such a preparation that Glaser (1921) was dealing in his description of secretions from the unfertilized egg. MacMunn (1885) observed the clotting of eleocytes from the periviscel~l fluid of Strongyloc~trotus l i~us.