Occurrence of free ecdysteroids and yolk protein ecdysteroid conjugates in the embryo of the melon fly, Dacus cucurbitae Coquillet

dc.contributor.author Sanders, Deborra A. en_US
dc.date.accessioned 2009-07-15T17:44:40Z
dc.date.available 2009-07-15T17:44:40Z
dc.date.issued 1990 en_US
dc.description Typescript. en_US
dc.description Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. en_US
dc.description Includes bibliographical references (leaves 68-72) en_US
dc.description Microfiche. en_US
dc.description ix, 73 leaves, bound col. ill. 29 cm en_US
dc.description.abstract The titer of ecdysteroids occurring in the embryos of the melon fly, Dacus cucurbitae Coquillet was determined at each developmental hour by radioimmunoassay. Free ecdysteroids were extracted from eggs in 60% methanol which showed one single peak at 18 h (i.e., time of germ band shortening). The maximal concentration of free ecdysteroids was 81 pg of 20 hydroxyecdysone equivalents per g. No observed morphological changes occurred during the 3 to 4 h peak hormone concentration. The involution of the head and the beginning of the dorsal closure of the midgut were observed during the declining concentration of free ecdysteroids. Embryonic cuticle was secreted ca. 5 to 6 h after the peak concentration of hormone. The major yolk protein (vitellin) was isolated and digested with several proteases to release ecdysteroid conjugates. The extracted conjugates became more immunopositive when hydrolyzed with Helix enzymes. Low amounts of ecdysteroid conjugates were detected in newly oviposited and young embryos. During late embryogenesis, ca. 18 h after oviposition, three peaks of ecdysteroid conjugates were detected. At 19 h, the first maximal concentration of 20 hydroxyecdysone equivalents was 85±1.7 pg/g vitellin. The second and third peaks occurred at 22 and 26 h with maximal concentrations of 20 hydroxyecdysone equivalents 106.5±1.7 and 102±2.3 pg/g vitellin, respectively. The vitellin of the melon fly was composed of two polypeptides, having a molecular weight of 48,000 and 52,000 and an isoelectric point of 6.3. en_US
dc.identifier.uri http://hdl.handle.net/10125/9767
dc.language.iso en-US en_US
dc.relation Theses for the degree of Doctor of Philosophy (University of Hawaii at Manoa). Entomology; no. 2526 en_US
dc.rights All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner. en_US
dc.subject Melon fly en_US
dc.title Occurrence of free ecdysteroids and yolk protein ecdysteroid conjugates in the embryo of the melon fly, Dacus cucurbitae Coquillet en_US
dc.type Thesis en_US
dc.type.dcmi Text en_US
Files