CYTOLOGICAL STUDIES DURING GERMINAL VESICLE BREAKDOWN OF PECTINARIA GOULDII WITH VITAL DYES, CENTRIFUGATION AND FLUORESCENCE MICROSCOPY

¹ Department of Biology, University of Notre Dame, Notre Dame, Indiana, and Marine Biological Laboratory, Woods Hole, Massachusetts

1. Living eggs of Pectinaria gouldii were stained with vital dyes and vital fluorochromes before and after germinal vesicle breakdown. Observations were made with the bright field, dark field and fluorescence microscopes. Changes in the germinal vesicle, nucleolus and chromosomes of the living eggs were followed.

2. Other eggs were vitally dyed and centrifuged in order to stratify the cell particulates. Cell granules were identified, based upon their specific staining and their stratified position in the centrifuged egg. These included lipid droplets, lipid granules, mitochondria, proteid yolk, basophilic and cortical granules. Limited cytochemical tests were made to verify their identity.

3. Two kinds of metachromatic granules were seen. With toluidine blue, the granules occur at the centripetal pole just beneath the lipid cap. When Nile blue sulphate was applied, a different metachromatic band stratified just centripetal to the heavier yolk granules. Astral granules originate from the latter metachromatic band and became associated with the first maturation spindle.

4. The fluorescent cell components included cell and nuclear membranes, nucleoli, chromosomes, lipid granules, two types of yolk granules and mitochondria.