title: The Y-organ secretory activity fluctuates in relation to seasons of molt and reproduction in the brachyuran crab, Metopograpsus messor (Grapsidae): Ultrastructural and immunohistochemical study.
abstract: This paper presents a first-time report on the localization, structure and seasonal secretory activity of the Y-organ of a grapsid brachyuran crab (Metopograpsus messor). Having exhibited discrete seasonality with reference to the programming of molt and reproduction, this brachyuran crab has offered us an excellent model to obtain a clear picture of the fluctuating secretory nature of the Yorgan, all the way through the reproductive (August-December) as well as the molt-reproduction active (January-May) and inactive (June-July) seasons. Ultrastructural studies revealed that the secretion of the Y-organ was at its peak in premolt crabs during molt-reproduction season (January-May). Interestingly, the Y-organs of the intermolt females that engaged in breeding activity showed higher levels of secretion than those of the molt-reproduction inactive season (June-July), implicating the gland's involvement in reproduction. Immunohistochemical studies using the antiserum raised against 2-succinyl conjugate of ecdysone have demonstrated the ecdysteroid nature of the secretion from the Y-organ, and results of the quantitative assay of ecdysteroids (through radioimmunoassay) revealed that the hormone titer fluctuates in consonance with the Y-organ's secretory activity during seasons of molt and reproduction. Pertinently, not only that the paper gives us a comprehensive understanding on the secretory activity of the Y-organ in a season-dependent fashion, it also allows us to have a better insight into the gland's function related to molting and reproduction (for the first time) in a grapsid brachyuran crab.
authors.affiliation: School of Biosciences & Technology, VIT University, Vellore 632014, Tamil Nadu, India.
authors.forename: Sharmishtha
authors.initials: S
authors.lastname: Shyamal
authors.affiliation: PG Department of Zoology, Sree Narayana College, Kannur 670007, Kerala, India.
authors.forename: K
authors.initials: K
authors.lastname: Sudha
authors.affiliation: Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore 560027, India.
authors.forename: N
authors.initials: N
authors.lastname: Gayathri
authors.affiliation: School of Biosciences & Technology, VIT University, Vellore 632014, Tamil Nadu, India. Electronic address: gopianilkumar@gmail.com.
authors.forename: G
authors.initials: G
authors.lastname: Anilkumar
mesh_terms: D000818:Animals; D003386:Brachyura / Q000254:growth & development / Q000378:metabolism*; D004440:Ecdysone / Q000276:immunology; D026461:Ecdysteroids / Q000378:metabolism*; D005088:Exocrine Glands / Q000378:metabolism* / Q000648:ultrastructure*; D005260:Female; D007124:Immunoenzyme Techniques; D008854:Microscopy, Electron; D018978:Molting; D012098:Reproduction / Q000502:physiology*; D012621:Seasons
chemical_list: D026461:Ecdysteroids; D004440:Ecdysone
keywords: Brachyura; Ecdysteroid; Immunohistochemistry; Metopograpsus messor; Ultrastructure; Y-organ