8,567 research outputs found

    Experimental confirmation of protandric simultaneous hermaphroditism in a Caridean shrimp outside of the genus Lysmata

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    Caridean shrimps display a variety of sexual systems including gonochorism and various forms of protandry but rarely simultaneous hermaphroditism. Protandric simultaneous hermaphroditism (PSH) has thus far only been demonstrated in the genus Lysmata. The first report of simultaneous hermaphroditism in a caridean shrimp was with Exhippolysmata ensirostris. However, this was not confirmed, since this species was also considered to be strictly protandric. Therefore, inconclusive results about this species’ true sexual system led us to examine Exhippolysmata oplophoroides. Mating between female phase individuals resulted in successful spawning, embryonic development and hatching of viable larvae. Furthermore, we have confirmed that this species is not capable of self-fertilization. Juveniles reared in the laboratory matured in a similar manner to that of Lysmata. Data were limited due to the loss of all individuals to a Vibrio infection. However, the results obtained in this study conclusively affirm functionally that PSH occurs outside the genus Lysmata, in E. oplophoroides. Theories examining the evolution of PSH within decapods must be re-examined in light of the present data

    Characterization of atrazine-induced gonadal malformations in African clawed frogs (Xenopus laevis) and comparisons with effects of an androgen antagonist (cyproterone acetate) and exogenous estrogen (17beta-estradiol): Support for the demasculinization/feminization hypothesis.

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    Atrazine is a potent endocrine disruptor that both chemically castrates and feminizes male amphibians. It depletes androgens in adult frogs and reduces androgen-dependent growth of the larynx in developing male larvae. It also disrupts normal gonadal development and feminizes the gonads of developing males. Gonadal malformations induced by atrazine include hermaphrodites and males with multiple testes [single sex polygonadism (SSP)], and effects occur at concentrations as low as 0.1 ppb (microg/L). Here, we describe the frequencies at which these malformations occur and compare them with morphologies induced by the estrogen, 17beta-estradiol (E2) , and the antiandrogen cyproterone acetate, as a first step in testing the hypothesis that the effects of atrazine are a combination of demasculinization and feminization. The various forms of hermaphroditism did not occur in controls. Nonpigmented ovaries, which occurred at relatively high frequencies in atrazine-treated larvae, were found in four individuals out of more than 400 controls examined (1%). Further, we show that several types of gonadal malformations (SSP and three forms of hermaphroditism) are produced by E2 exposure during gonadal differentiation, whereas a final morphology (nonpigmented ovaries) appears to be the result of chemical castration (disruption of androgen synthesis and/or activity) by atrazine. These experimental findings suggest that atrazine-induced gonadal malformations result from the depletion of androgens and production of estrogens, perhaps subsequent to the induction of aromatase by atrazine, a mechanism established in fish, amphibians, reptiles, and mammals (rodents and humans)

    Hybridisation generates a hopeful monster: a hermaphroditic selfing cichlid

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    Compared to other phylogenetic groups, self-fertilization (selfing) is exceedingly rare in vertebrates and is known to occur only in one small clade of fishes. Here we report observing one F1 hybrid individual that developed into a functional hermaphrodite after crossing two closely related sexually reproducing species of cichlids. Microsatellite alleles segregated consistent with selfing and Mendelian inheritance and we could rule out different modes of parthenogenesis including automixis. We discuss why selfing is not more commonly observed in vertebrates in nature, and the role of hybridisation in the evolution of novel trait

    Defining Desire: Re(storyng) a 'fraudulent' marriage in 1901 Spain

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    In the second half of the 19th century, two Spanish primary school teachers were married despite the fact that their legal status as women rendered this union not only illegal but also publicly scandalous. In 2008 their story was resurrected in the form of a book based on an extensive review of educational, legal, and media archives. The Spanish press responded to the book’s publication by embedding the events within a more recent historical narrative around the struggle for gay marriage rights. In this article, we analyze the events in light of the understandings of sex, gender and sexuality that were available at the time, and then explore both the continuities and discontinuities with the modern interpretive framework that affords these women a lesbian identity, drawing upon Bennett’s notion of ‘‘lesbian-like’’ practices in eras where such identities were not yet conceptualized

    Androgyny/Hermaphroditism: Hebrew Bible

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    The Hebrew Bible lacks a term for androgyny or hermaphroditism. The term tumtumim, which identifies persons of indeterminate or “hidden” sex, appears later in rabbinic texts. Nevertheless, sexual fluidity, ambiguity, intersexed persons, and persons with a combination of masculine and feminine characteristics appear in the Genesis creation stories and prophetic texts. While gender transgression is relevant to the general discussion, this entry from The Oxford Encyclopedia of the Bible and Gender Studies: Oxford Biblical Studies Online focuses primarily on ancient understandings, namely those presented in the Hebrew Bible, of those of “both sexes.

    Density-dependent effect on reproductive behaviour of Lysmata amboinensis and L. boggessi (Decapoda: Caridea: Hippolytidae)

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    We compared the reproductive behaviours of two protandric simultaneous hermaphroditic species (Lysmata amboinensis and L. boggessi) that belong to two groups of Lysmata shrimp with different morphology, geographical distribution, and density. Lysmata amboinensis occurs in tropical waters at low population densities, and L. boggessi is found in aggregation in sub-tropical and temperate areas. Reproductive behaviour of L. boggessi under two densities and L. amboinensis in different habitats were compared. Results show that L. amboinensis was much less active during mating than L. boggessi. Male shrimp of L. amboinensis did not display obvious pre-copulation behaviour. They also took significantly longer to transfer spermatophores and lay eggs after mating than L. boggessi shrimp did. For L. boggessi, moulting time of female shrimp, copulation time and the interval between moulting and mating were significantly shorter when three male shrimp were present than when only one male shrimp was present. Our study suggests that the reproductive behavioural differences in the two shrimp species are possibly the results of density-dependent effect

    Action of the Metalloproteinases in Gonadal Remodeling during Sex Reversal in the Sequential Hermaphroditism of the Teleostei Fish Synbranchus marmoratus (Synbranchiformes: Synbranchidae)

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    Teleostei present great plasticity regarding sex change. During sex reversal, the whole gonadincluding the germinal epithelium undergoes significant changes, remodeling, and neoformation.However, there is no information on the changes that occur within the interstitial compartment.Considering the lack of information, especially on the role played by metalloproteinases (MMPs)in fish gonadal remodeling, the aim of this study was to evaluate the action of MMPs on gonadsof sex reversed females of Synbranchus marmoratus, a fresh water protogynic diandric fish. Gonadswere processed for light microscopy and blood samples were used for the determination of plasmasex steroid levels. During sex reversal, degeneration of the ovaries occurred and were graduallyreplaced by the germinal tissue of the male. The action of the MMPs induces significant changesin the interstitial compartment, allowing the reorganization of germinal epithelium. Leydig cellsalso showed an important role in female to male reversion. The gonadal transition coincides withchanges in circulating sex steroid levels throughout sex reversion. The action of the MMPs, in thegonadal remodeling, especially on the basement membrane, is essential for the establishment of anew functional germinal epithelium.Fil: Mazzoni, Talita Sarah. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Lo Nostro, Fabiana Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Ecotoxicología Acuática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Antoneli, Fernanda. Universidade Estadual de Campinas; BrasilFil: Quagio-Grassiotto, Irani. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

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    'A woman like any other' : female sodomy, hermaphroditism and witchcraft in seventeenth-century Bruges

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    This article discusses the official and popular responses to a particular sodomy trial held at Bruges in 1618 during which two women, Mayken and Magdaleene, were accused of several sexual and moral transgressions. The interrogation records of the accused female sodomites illustrate the remarkable self-consciousness of early modern women with same-sex desires. Their attitudes collided, however, with popular mentalities towards female sodomy, which local testimonies explained away as a physical abnormality or an act of diabolical witchcraft. This article offers an in-depth analysis of these discourses in order to gain a fuller understanding of the perception of female sodomy in early modern urban society
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