Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2006. / "Title from dissertation home page (viewed July 17, 2007)." Source: Dissertation Abstracts International, Volume: 67-10, Section: B, page: 5603. Adviser: Michael Lynch.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 0875. Adviser: Kimberly A. Hughes. Includes bibliographical references (leaves 115-125) Available on microfilm from Pro Quest Information and Learning.

<p> Polychlorinated biphenyls (PCBs) negatively affect reproduction across taxa. However, how PCBs influence elasmobranchs is not well known. I hypothesized that acute PCB exposure would negatively impact reproductive parameters of newly-mature round stingrays (<i>Urobatis halleri</i>). To determine the acute effects of PCBs on steroidogenesis, male stingrays were injected with either Aroclor-1254 or vehicle (sesame-oil) and held for 24 hrs. Testicular mRNA expression for steroidogenic acute regulatory protein and 3&beta;-hydroxysteroid dehydrogenase decreased with 24 hrs exposure to Aroclor-1254 (p&lt;0.05). To test sperm quality, seminal fluid was exposed to Aroclor-1254 (0.00, 0.001, 0.010, 0.100, 1.000, 10.00 mg/L) for &lt; 1 or 24 hrs. Aroclor-1254 (10.00 mg/L) decreased spermatozoa motility and viability at both time-points compared to controls (p&lt;0.001). At &lt; 1 hrs, spermatozoa motility decreased from the control at 1.000 mg/L (p&lt;0.05) and viability decreased at 0.010 mg/L (p&lt;0.05). These results indicate that Aroclor-1254 may have targeted effects on <i>U. halleri</i>, inhibiting spermatozoa function and steroidogenic enzyme activity at an acute dose.</p>

Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2005. / Title from PDF t.p. (viewed Dec. 3, 2008). Source: Dissertation Abstracts International, Volume: 66-03, Section: B, page: 1279. Chair: Michael J. Wade.