The juvenile three-spined stickleback : model organism for the study of estrogenic and androgenic endocrine disruption in laboratory and field

Industrial and domestic sewage effluents have been found to cause reproductive disorders in wild fish, often as a result of the interference of compounds in the effluents with the endocrine system. This thesis describes laboratory-based exposure experiments and a field survey that were conducted with juveniles of the three-spined stickleback, Gasterosteus aculeatus. This small teleost is a common fish in Swedish coastal waters and was chosen as an alternative to non-native test species commonly used in endocrine disruption studies, which allows the comparison of field data with results from laboratory experiments. The aim of this thesis was to elucidate 1) if genetic sex determination and differentiation can be disturbed by natural and synthetic steroid hormones and 2) whether this provides an endpoint for the detection of endocrine disruption, 3) to evaluate the applicability of specific estrogen- and androgen-inducible marker proteins in juvenile three-spined sticklebacks, 4) to investigate whether estrogenic and/or androgenic endocrine disrupting activity can be detected in effluents from Swedish pulp mills and domestic sewage treatment plants and 5) whether such activity can be detected in coastal waters receiving these effluents. Laboratory exposure experiments found juvenile three-spined sticklebacks to be sensitive to water-borne estrogenic and androgenic steroid substances. Intersex – the co-occurrence of ovarian and testicular tissue in gonads – was induced by 17β-estradiol (E2), 17α-ethinylestradiol (EE2), 17α-methyltestosterone (MT) and 5α-dihydrotestosterone (DHT). The first two weeks after hatching was the phase of highest sensitivity. MT was ambivalent by simultaneously eliciting masculinizing and feminizing effects. When applying a DNA-based method for genetic sex identification, it was found that application of MT only during the first two weeks after hatching caused total and apparently irreversible development of testis in genetic females. E2 caused gonad type reversal from male to female. E2 and EE2 induced vitellogenin - the estrogen-responsive yolk precursor protein, while DHT and MT induced spiggin – the androgen-responsive glue protein of the stickleback. None of the effluents from two pulp mills and two domestic sewage treatment plants had any estrogenic or androgenic activity. Juvenile three-spined sticklebacks were collected during four subsequent summers at the Swedish Baltic Sea coast in recipients of effluents from pulp mills and a domestic sewage treatment plant as well as remote reference sites. No sings of endocrine disruption were observed at any site, when studying gonad development or marker proteins, except for a deviation of sex ratios at a reference site. The three-spined stickleback – with focus on the juvenile stage – was found to be a sensitive species suitable for the study of estrogenic and androgenic endocrine disruption.

Stereotypes below the Surface : A Comparative Study of Three Popular Young Adult Novels in the Romantic Fantasy Genre

In recent years, the young adult genre has become increasingly popular and is experiencing a "second golden age.” It might be expected in such novels, when written by women and featuring gifted female heroines, to find some kind of a feminist message. Indeed, the heroines are often perceived as strong and capable. However, they fall in line with several old gender stereotypes. The three novels chosen for this study are: A Court of Thorns and Roses by Sarah J. Maas, Red Queen by Victoria Aveyard and An Ember in the Ashes by Sabaa Tahir. I will show that women, although perceived as strong and capable on the surface, often conform to stereotypes. In order to do this I analyse how women are portrayed from different perspectives. Women are often perceived as passive in romantic situations, and objectified through the normative male gaze. It is interesting that also in novels written by women for women, the male gaze is prominent. Through this the female reader gains the desire to be objectified, implicitly from the narrative, which is something that works against women’s empowerment in society. Furthermore, the female protagonists rarely, or never, threaten patriarchy in any way and generally work toward reinstating patriarchy which is perceived as the only sensible option. Women in power, who do threaten patriarchy, are portrayed as sadistic witches.