Developmental Modifications in Arbacia Punctulata by Various Metabolic Substances

Abstract

Normal development is a sequela of normal cellular differentiation. In order to understand the precise programming in development, be it molecular or morphologic, attention must be given to the properties of the individual developing cell and its organelles and its metabolic events, as well as the overall susceptibility of response of the whole organism during development.Major steps in the understanding of echinoid developmental biology have been made by experimental approaches which have brought about aberrations in development (see review by Lallier, 1964a) and more recently by biochemical analyses of these events (see review by Monroy and Maggio, 1964).The present report concentrates on the response of the embryo as a whole organism to a variety of agents. By comparison with the normal sequences in development, these changes may provide insight into the mode of action, especially where a differential response is elicited.The first experiments were based on Heath's (1954) observation that persistent nucleoli resulted when 1 to 1.5 X 10" 5 gm./ml. cobalt chloride was added to cultures of chick heart and frontal bone. These persistent nucleoli remained in association with chromosomes during metaphase but were torn in two or adhered to one chromosome at anaphase. They remained in the cytoplasm despite reconstitution of new nucleoli in daughter cells. The early sea urchin experiments were designed to duplicate the unique cobalt effect, thereby, hopefully, pinpointing critical stages during early development (Mateyko, 1961). The prominent nucleolus, a characteristic feature of the large germinal vesicle in the oocyte of Arbacia has always attracted attention. To illustrate, recently, Esper (1965) discussed the cytochemistry of its vacuole. But the information on nucleoli in blastomeres of echinoids is difficult to assess. In fact, it was only recently that the karyotype of Arbacia punctulata was published (Auclair, 1965). German (1964) demonstrated that of the 44 chromosomes, two pairs were considerably larger. Whether these are the nucleolar-organizer chromosomes or even whether nucleoli are organized into compact bodies associated with specific chromosomes in the early cleavage stages is not established. Cowden and Lehman (1963) demonstrated that there were no nucleoli in the blastula of Lytechinus verigatits (sic) or Melita quinqiiesperforata (sic). It was only at the early gastrula, 12 hours post-fertilization, that nucleoli became visibly organized. Is "blastulation" used in the sense of the onset of asynchrony, and this inception of differentiation a critical moment in nucleolar phe-

Use of the Sea Urchin Egg for Quick Screen Testing of the Biological Activities of Substances I. Influence of Fractions of a Tobacco Smoke Condensate on Early Development

“…Effects of different substances such as metabolic inhibitors on the sea urchin egg have occasionally been described. Most of these results have been reported by Harvey (1 ) and Mateyko (2). We have used different fractions of a condensate of tobacco smoke to demonstrate the significance of this system.…”

Development of the Sea Urchin Arbacia Punctulata in the Presence of the Environmental Toxin Sodium Hypochlorite

“…Bioaccumulation [9,10], development and embryotoxicity [11][12][13], and more recently genotoxicity and genetic mutation [14][15][16] are the primary areas of concern for these toxins. These toxins can have potent effects on embryos: concentrations of 250 mg·Pb·l -1 can cause accumulation of 3 mg·Pb·g -1 dry weight [9].…”