Olin Rulon

The Modification of Developmental Patterns in the Sand Dollar by Sodium Selenite

E :PERIMENTS dealing with the modification of developmental pattern in the echinoderm egg by external agents are not new. Sixty years ago Herbst (1892) discovered that lithium would cause exogastrulation and vegetalization in the developing larva of the sea urchin. Child (1941a, pp. 197-246) reviewed the various agents that affect development differentially and pointed out that differential inhibition, differential recovery, and differential conditioning in a quantitatively graded physiological system may be largely responsible for modifications in development caused by external agents. Recently, others (Hbrstadius and Gustafson, 1947; see Hirstadius, 1949, for review) have found that certain substances (propanediol phosphate, phosphogluconic acid, lactate), which are thought to play a role in carbohydrate metabolism, cause an animalization in apical halves of the sea-urchin egg, while other substances (certain amino acids), which may tend to favor protein metabolism, cause vegetalization. Also recently, the author (Rulon, 1949; 1950a, b; 1951) has shown that in the developing egg of the sand dollar (Dendraster excentricus) certain enzyme inhibitors (azide, thiourea) promote vegetalization, while others (maleic acid, malonic acid) promote overdevelopment of the animal region. The different inhibitors also have other dissimilar effects. In continuation of this work and in an effort to learn more con-

Modification of Development in the Sand Dollar by NaCNS and Ca-Free Sea Water

IN IN RECENT years the dynamics of echinoderm development has attracted the attention of such noted investigators as RunnstrPm (1914, 1915, 1917, 1918, 1933, 1935), H6rstadius (1935, 1937, 1939), Lindahl (I933, 1936), von Ubisch (I925, I929), Child (1915, 1916a, 1916b, 1929, 1936a, 1936b, 1940), and many others. The Runnstrdm school at Stockholm has been inclined to look upon the pattern in the early development of the echinoderm egg as the result of an interaction of two opposed material gradients. According to these workers, the animal gradient, extending from the animal to vegetal pole of the egg, tends to ectodermize the larva, while the opposing gradient, from the vegetal to animal pole, tends to entodermize the larva. Child, on the other hand, has shown with the aid of vital dyes a reduction gradient from the animal to vegetal poles in the early stages. This, together with numerous experiments on larval modifications, has led to the belief that a polar activity gradient may be the primary developmental pattern. He suggests (1936a) that the different fields (such as the entoderm field of the late blastula) arise through a process of partial physiological isolation from the primary, or polar gradient. The work here undertaken deals with the modification of development with NaCNS and Ca-free sea water as test agents in an attempt to throw additional light on the subject of early developmental patterns.

Effects of Cobaltous Chloride on Development in the Sand Dollar

KREHL, L., and SOETBEER, F. 1899. Untersuchungen tiber die Wirmedkonomie der poikilothermen Wirbelthiere. Arch. f. d. ges. Physiol., 77:611-38. LEICITENTRITT, B. 1919. Die Wirmeregulation neugeborener Slugetiere und Vigel. Zeitschr. f. Biol., 69:545-63. MARTIN, C. J. 1903. Thermal adjustment and respiratory exchange in monotremes and marsupials: a study in the development of homoeothermism. Phil. Trans. Roy. Soc. London, B, 195:137.

The modification of developmental patterns in the sand dollar with sodium azide.

i. An apparatus is described which has certain advantages over the usual equipment employed to study the reaction of protozoan cells to electric currents. 2. The reactions of P. carolinensis to a direct current are described, and the current densities required to produce the observed effects are given. 3. At a specified current density, the time required for Pelomyxa to break is directly correlated with the size of the cell. 4. At a fixed current density, calcium increases the breaking time of both large and small cells without altering the sizebreaking-time relationship. 5. It is pointed out that conclusions concerning the charge on the intact cell or on the granules released at rupture cannot be drawn from the data of this paper or from numerous other reports in the iiterature.

The Experimental Modification of Developmental Patterns in Arbacia with Malonic Acid

bryo in the changes in riboflavin of the egg. 2. Fluorometric and spectrometric data are presented for both normal and X-irradiated eggs. 3. Eggs in which the embryo is destroyed by X-irradiation show little if any change in their riboflavin content. Normal or embryo-containing eggs show marked changes in riboflavin, especially late in embryonic development. 4. Riboflavin is converted into pterines only in nonirradiated or normal eggs. 5. The conversion of riboflavin into pterines seems to be a specific property of the embryo per se and not of differentiated extra-embryonic structures, such as the serosa.

Modifications of Sand-Dollar Development by Exposure to Lithium Chloride and Sodium Thiocyanate before and after Fertilization

BENEDICT, S. R., and FRANKE, E. J. I922. A method for the direct determination of uric acid in urine. Jour. Biol. Chem., 52:387-91. BODINE, J. H. 1932a. Hibernation and diapause in certain Orthoptera. II. Response to temperature during hibernation and diapause, Physiol. Zo6l., 5:538-48. . I932b. Hibernation and diapause in certain Orthoptera. III. Diapause-a theory of its mechanism. Ibid., pp. 549-54. BODINE, J. H., and BOELL, E. J. 1936. Respiration of embryos vs. egg (Orthoptera). Jour. Cell. and Comp. Physiol., 8:357-66. BOELL, E. J. 1935. Respiratory quotients during embryonic development (Orthoptera). Jour. Cell. and Comp. Physiol., 6:369-85. CHRISTMAN, A. A., and RAVWITCH, S. 1932. The determination of uric acid in human urine. Jour. Biol. Chem., 95:115-26. HILL, D. L. I943. Certain relationships between carbohydrate and respiratory metabolism during embryonic development (Orthoptera). Anat. Rec., 87:449. (Abstract.) LEIFERT, H. 1935. Untersuchungen iber den Exkretstoffwechsel beim Eiern, Raupen und Puppen von Anteraca pernyi. Zool. Jahr., Abt. f. Allg. Zool. u. Physiol., 55:131-70.

The Modification of Developmental Pattern in the Sand Dollar by Malonic Acid

frequency gradient in Euplanaria dorotocephala. Physiol. Zo6l., 8:1-40. MILLER, F. S. 1937. Some effects of strychnine on reconstitution in Euplanaria dorotocephala. Physiol. Zo6l., 10o: 276. PEASE, D. C. 1942. Echinoderm bilateral determination in chemical concentration gradients. II. Jour. Exper. Zo6l., 89:329-45. RULON, O. 1941. The alteration of developmental pattern in the sand dollar by pilocarpine. Physiol. Zohl., 14:461-69. RULON, 0., and CrHILD, C. M. 1937. Experiments on scale of organization in Euplanaria dorotocephala. Physiol. Zol., o10:396-404. WATANABE, Y. 1935a. Rate of head development as indicated by time of appearance of eyes in the reconstitution of Euplanaria dorotocephala. Physiol. Zo6l., 8:41-64.

The Modification of Developmental Patterns in the Sand Dollar with Maleic Acid

F oR the last ten years, whenever conditions permitted, the author has spent the summers either at Pacific Grove or at Woods Hole, working on the problem of control of echinoderm development through the use of external agents. Many chemicals have been used; and, commonly, entirely different ones, within certain effective concentrations, produced similar effects (inhibition of cleavage, excess mesenchyme, exogastrulation, etc.). But this was not always so. LiC1 and NaCNS (in Ca-free sea water) before fertilization have exactly opposite effects on the sand-dollar egg, in that lithium produces entodermization while thiocyanate causes ectodermization. The author (Rulon, 1941a, 1946) has suggested that this difference in action of the two agents may be due largely to a more rapid recovery, with an increased scale of organization, of the eggs from NaCNS than from LiC1 on return to sea water and fertilization. Since data on the actual effects of these different agents on prefertilization metabolism, etc., were lacking, this suggestion has never been entirely satisfactory, although it may well be the correct one. The author is in complete agreement with the theory that over-all quantitative activity gradients in the developing

The Alteration of Developmental Pattern in the Sand Dollar by Pilocarpine

OTHER work on the dynamics of echinoderm development (Child, I936a, 1936b, 1940; Rulon, 1938, 1941) has shown that such agents as lithium and sodium thiocyanate affect early developmental pattern primarily through inhibitory action. The inhibition of certain active regions may be followed secondarily by recovery effects, depending upon the experiment, to produce modifications of widely different types. Differential conditioning may also take place in low concentrations. By recognizing differential inhibition, recovery, and conditioning in the modified embryo it is possible to tell something of the time of origin, the localization of particular fields, the development of symmetry, and other factors operating in the progressive development of the normal pattern. With data on the effects of inhibitory action available, it seemed desirable to test the effect on developmental patterns of an agent which reputedly has a stimulating action. Since there were many indications that pilocarpine might fill this need, a number of experiments were performed with this substance as the test agent.

Single and Combined Effects of Cyanide and Methylene Blue on Reconstitution in Euplanaria dorotocephala

IT IT HAS long been known that cyanide exerts its chief effects on living protoplasm by inhibiting respiratory metabolism. It is also known that cyanide may retard cell division and growth. Certain experiments by various workers (Hug, 1932; Brooks, 1932, 1933; Bodine and Boell, 1936, 1937; and others) have shown that methylene blue, in certain concentrations, will antagonize the poisonous effects of cyanide and restore the normal respiration in whole adult animals and in developing embryos. In contrast with the effects of cyanide, methylene blue has been found, in certain cases, to increase the rate of respiratory metabolism above the normal.