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Lookup NU author(s): Sylvie-Marylene Gaudron, Emeritus Professor Matt Bentley
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Endocrine and environmental factors have been shown to control reproduction of the scale worm Harmothoë imbricata and recent studies have highlighted a possible link between oogenesis, spawning and sex pheromone production in this species (Watson et al., 2000). Results presented here demonstrate the links between photoperiod, hormonal control of oogenesis and oocyte maturation. A gonadotrophic hormone controlling vitellogenesis in oocytes is produced by the prostomium and its production is under environmental control. Implantation of prostomia from individuals conditioned in LD16:8 (long day) photoperiod into individuals conditioned in LD8:16 (short day) accelerates growth of the oocytes. Implantation of prostomia from LD8:16 conditioned individuals, into decerebrated individuals from LD8:16, re-establishes normal oocyte growth (as seen in individuals maintained in short day). After 2 weeks long-day conditioning, oocyte growth becomes independent of the neurohormone. A second hormone acts to bring about maturation. This putative hormone induces oocyte maturation (progression from meiotic prophase I to metaphase I). This meiotic reinitiation of oocytes is obtained by incubation of fully sized but immature oocytes with prostomial homogenate (using prostomia from females just prior the spawning date or from active males). Preliminary purification of the maturation-inducing substance shows that it is a heat-stable substance and has a molecular mass probably around 3 kDa. It is possible, but has not been demonstrated unequivocally, that the maturation hormone is the "putative spawning hormone" described recently in Harmothoë imbricata (Watson et al., 2000).
Author(s): Gaudron SM, Bentley MG
Publication type: Article
Publication status: Published
Journal: Invertebrate Reproduction and Development
Year: 2002
Volume: 41
Issue: 1-3
Pages: 109-118
ISSN (print): 0792-4259
ISSN (electronic):
Publisher: Balaban Publishers
