Understanding the Factors Driving Intra-Specific Variations of Contaminants in Urban-Adapted Birds and their Endocrine and Metabolic Impacts

在高度城市化的环境中，越来越多的具有潜在环境问题的新的有机污染物不断被排放到陆地和水生生态系统中，并有可能发生生物累积，对鸟类等最易受影响的野生物种有毒。这可能是许多新兴的卤化阻燃剂（HFR）的情况，尽管它们在全世界范围内广泛地用于各种消费品和工业产品中以达到消防安全标准，即减缓火灾的蔓延，但没有国家或国际法规。我的实验室最近进行的一项研究报告了高浓度的HFR类多溴联苯醚（PBDEs）以及一些尚未发现的新出现的HFR在蒙特利尔地区繁殖的一种丰富的城市适应鸟类的组织中，环嘴鸥（Larus delawarensis）。我实验室的证据表明，内分泌系统（例如，甲状腺轴）和某些相关终点（例如，能量代谢）可能会受到不利影响，在大多数HFR暴露的环嘴鸥。拟议的NSERC危险品研究计划的短期目标将是调查：1）控制对野生动物健康影响最大的新型和新出现的HFRs在环嘴鸥中的生物累积和母体转移的生物因素; 2）环嘴鸥对选定的新出现的HFRs的体外生物转化能力; 3）通过对环嘴鸥和鸡的甲状腺激素和皮质酮水平的分析，探讨了部分新出现的HFRs对环嘴鸥和鸡两个内分泌轴的毒性效应及其潜在机制，参与其调节的基因的mRNA转录以及脂质组成（脂质组学）和场代谢率（FMR;测量动物的总能量消耗）。拟议研究的新奇和预期意义在于，生物累积、生物转化和与安全相关的健康影响（例如，内分泌、代谢率、脂质代谢）对暴露于目前使用的污染物（包括HFRs）的动物的影响是研究不足的领域。这项工作的另一个重要方面是比较方法，即检查自然接触的鸟类种群（海鸥）和鸟类模型（鸡）之间化学品引起的影响的差异。因此，这项拟议的研究计划将提供新的知识，在加拿大环境中的新的化学应激源的动态和生物活性。此外，它将为一名博士提供独特的HQP培训机会。三名理学硕士和五名B.Sc.荣誉学生，研究动物生物能量学、生态毒理学、生物能量学、内分泌学、分析化学和脂质组学的新方面。

A growing number of new organic contaminants of potential environmental concern are constantly discharged into terrestrial and aquatic ecosystems in highly urbanized environments, and have the potential to bioaccumulate and be toxic to the most susceptible wildlife species such as birds. This may be the case for the numerous emerging halogenated flame retardants (HFRs) for which no national or international regulations exist despite their massive (and growing) usage worldwide in a wide range of consumer and industrial products to achieve fire safety standards, that is, to slow down the spread of fire. A recent study conducted by my lab reported unexpectedly high concentrations of the HFR class polybrominated diphenyl ethers (PBDEs) as well as several as yet undetected emerging HFRs in tissues of an abundant urban-adapted avian species, the ring-billed gull (Larus delawarensis), breeding in the Montreal area. Evidence from my lab suggests that the endocrine system (e.g., thyroid axis) and certain related endpoints (e.g., energetic metabolism) may be adversely affected in the most HFR-exposed ring-billed gulls. The short-term objectives of the proposed NSERC DG research program will be to investigate: 1) the biological factors governing the bioaccumulation and maternal transfer in ring-billed gulls of novel and emerging HFRs of greatest health concern for wildlife; 2) the in vitro biotransformation capacity in ring-billed gulls towards selected emerging HFRs; and 3) the exposure-related effects and underlying mechanisms of toxicity of selected emerging HFRs on two endocrine axes in ring-billed gulls and chicken via analysis of thyroid hormone and corticosterone levels, mRNA transcription of genes involved in their regulation as well as lipid composition (lipidomics) and field metabolic rate (FMR; measures an animal's total energy expenditure). The novelty and expected significance of the proposed research is that the bioaccumulation, biotransformation, and exposure-related health impacts (e.g., endocrine, metabolic rate, lipid metabolism) on animals exposed to currently used contaminants including HFRs are understudied fields of research. One other significant aspect of this work is the comparative approach, that is, the examination of differences in chemically-induced effects among naturally-exposed bird populations (gull) and an avian model (chicken). This proposed research program will thus provide new knowledge on the dynamics and bioactivity of novel chemical stressors in the Canadian environment. Furthermore, it will represent a unique HQP training opportunity for one Ph.D. and three M.Sc. students as well as five B.Sc. honour students in novel aspects of animal bioenergetics, ecotoxicology, bioenergetics, endocrinology, analytical chemistry, and lipidomics.