Halem Zachery M, Ross Dustin J, Cox Rachel L
The Lisman Research Laboratories at Riverdale Country School, Bronx, NY, USA.
The Lisman Research Laboratories at Riverdale Country School, Bronx, NY, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2014 Sep;175:1-6. doi: 10.1016/j.cbpa.2014.04.016. Epub 2014 May 9.
Populations undergo physiological adaptations in response to environmental stressors. Our 5-year bio-monitoring study of the Bronx River Estuary demonstrates comparatively low dissolved oxygen concentrations in this urbanized watershed. Additionally, our current results establish altered hormonal levels, resulting from endocrine disruption, in Geukensia demissa (Atlantic ribbed mussel) from the Bronx River Estuary. No studies have yet investigated a correlation between low dissolved oxygen and endocrine disruption in field-collected bivalves. Testosterone, estradiol, and progesterone levels were collected from male and female mussels in the oxygen depleted Bronx River and well-oxygenated Greenwich Cove. Bronx River mussels exhibited higher testosterone levels and lower estradiol levels than Greenwich Cove mussels. The resulting abnormal hormonal ratio seems to indicate that environmental conditions in the Bronx River facilitate an allosteric inhibition of the cytochrome P450 aromatase enzyme, which aids conversion of testosterone to estradiol. Low progesterone levels suggest that Bronx River mussels are experiencing a delay in sexual maturation, and morphometric data show a stalling of shell and tissue growth. To confirm that the mussels collected from both sites are the same species, the universal mitochondrial cytochrome c oxidase subunit I gene was analyzed, through DNA barcoding. Minimal sequential heterogeneity confirmed the mussels are the same species. Such findings suggest intraspecific divergence in various endocrine processes, resulting from environmentally induced stress.
种群会因环境压力源而发生生理适应。我们对布朗克斯河河口进行的为期5年的生物监测研究表明，在这个城市化的流域中，溶解氧浓度相对较低。此外，我们目前的研究结果表明，布朗克斯河河口的Geukensia demissa（大西洋肋贻贝）因内分泌干扰而导致激素水平发生变化。尚未有研究调查过野外采集的双壳贝类中低溶解氧与内分泌干扰之间的相关性。从氧气耗尽的布朗克斯河和氧气充足的格林威治湾的雄性和雌性贻贝中采集了睾酮、雌二醇和孕酮水平。布朗克斯河贻贝的睾酮水平高于格林威治湾贻贝，而雌二醇水平低于格林威治湾贻贝。由此产生的异常激素比例似乎表明，布朗克斯河的环境条件促进了细胞色素P450芳香化酶的变构抑制，该酶有助于睾酮转化为雌二醇。低孕酮水平表明布朗克斯河贻贝的性成熟出现延迟，形态测量数据显示贝壳和组织生长停滞。为了确认从两个地点采集的贻贝是同一物种，通过DNA条形码分析了通用的线粒体细胞色素c氧化酶亚基I基因。最小序列异质性证实贻贝是同一物种。这些发现表明，环境诱导的压力导致了各种内分泌过程中的种内差异。
