Document Type



Virginia Institute of Marine Science

Publication Date



Biological Bulletin





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In the Scyphozoa, pronounced morphological changes occur during strobilation which are undoubtedly preceded by changes in gene activity, metabolic pathways, and biosynthetic mechanisms : the long tentacles of the scyphistoma are retracted and a series of transverse constrictions are formed at the oral end; each transverse section develops into an ephyra and subsequently into an adult medusa. This morphological development of Chrysaora quinquecirrha has been thoroughly studied by Littleford ( 1939) and Calder ( 1972) . Influences of environmental and chemical factors on strobilation of both Aunelia aunita and C. quinequecinrha have been investigated by many workers (Custance, 1964 ; Spangenberg, 1965, 1967, 1974; Loeb, 1970, 1973 ; Loeb and Gordon, 1975 ; Black and Webb, 1973 ; Olmon and Webb, 1974) . Black ( 1972) reported increased levels of DNA in the strobilae of A. aurita.

Isozymes are probably important in regulating tissue function, and such studies may provide information on the molecular basis of cellular differentiation ( Markert, 1975 ; Whitt, 1975). Investigations of the ontogeny of the most extensively studied enzyme, lactate dehydrogenase (EC , have been reviewed by Masters and Holmes ( 1972) , and the evaluation of gene structure, function and regulation have been reviewed by Markert, Shaklee and Whitt ( 1975) . The enzyme of interest, malate dehydrogenase (MDH, EC, has been studied in a few developing embryos of vertebrates, including the frog (MacBride and Guttman, 1973) , fish (Nakano and Whiteley, 1965; Shaklee, Champion, and Whitt, 1974), and chicken (Greenfield and Boell, 1970).

Only a limited number of MDH isozyme studies have been undertaken on the development of vertebrates. These include the nematode, Ascanis suuni (Zee and Zinkham, 1968) , the marine snail, Ilyanassa obsoleta (Meizel and Markert, 1967), and the sea urchins, Anbacia punctulata (Moore and Villee, 1961, 1962, 1963a, 1963b; Billiar, Brungard, and Villee, 1964; Billiar, Zelewski, and Villee, 1966; Francesconi and Villee, 1968; Villee, 1968) and Stnongylocentnotus purpunatus (Ozaki and Whiteley, 1970). In this study, the MDH isozyme patterns of different stages of the Chesapeake Bay jellyfish, A. aunita, C. quinquecirrha, and Cyanea capillata, were investigated as a model system for probing biochemical development of the simplest Animalia (Whittaker, 1969; Margulis, 1971).