An experimental test of the developmental stress hypothesis - fitness consequences of early versus late contaminant exposure

生物学家预测，生命早期的压力对生物体的影响应该比生命后期经历的同样压力更大。这个理论被称为发展压力假说，如果正确的话，意味着早期的压力经历可能会产生长期的影响，通过改变动物用来评估彼此作为配偶和/或竞争对手的线索来影响个体的健康。如果这一假设是正确的，那么考虑到环境压力，我们就有可能设计出更有效的保护和保护行动，因为我们知道某些个体如何以及为什么会相互交配并产生存活下来的后代的机制。本项目将通过研究一只经过充分研究的鸟类暴露于低水平汞后的生理、免疫、发育和行为后果来检验发育应激假说。斑马雀汞是一种全球性的毒素，但我们对少量非致命量的汞对人体的危害知之甚少。当前的联邦政府将汞污染描述为“我们今天面临的最重要的全球化学问题”，因此，增加我们对这种有害的移动的毒素对野生动物影响的了解，将对国家和国际上规范汞污染的努力产生重要影响。参与该项目的研究生和本科生将表明早期接触汞是否比后来接触同样少量的汞更具破坏性。试验数据表明，免疫系统将受到抑制，大脑功能受损，繁殖能力严重下降;这些影响在生命早期接触汞的情况下最为显著。这可能会改变我们对汞的“安全”水平的看法。由于斑胸草雀的大脑是理解人类语言学习的模型，因此该项目也将深入了解汞如何影响人类健康。

Biologists predict that stress early in life should have a larger effect on organisms than the same stress experienced later in life. This theory is called the developmental stress hypothesis and if correct means that early stress experiences may have long last effects that impact an individual fitness by altering cues that are used by animals to assess each other as mates and/or competitors. If this hypothesis is correct then may taking into account environmental stressors it is possible to design more effective preservation and conservation actions as we know the mechanisms for how and why certain individuals will mate with each other and produce offspring that survive. This project will test the developmental stress hypothesis by examining physiological, immunological, developmental, and behavioral consequences of exposure to low levels of mercury in a well-studied bird?the zebra finch. Mercury is a global toxin but we know little about how small non-lethal amounts of mercury harm the body. Mercury contamination has been described by the current Federal administration as the "most important global chemical issue facing us today", so increasing our understanding of the impact on wildlife of this pernicious and mobile toxin will have important implications for national and international efforts to regulate mercury pollution. Graduate and undergraduate students participating in this project will indicate whether early life exposure to mercury is more damaging than later exposure to the same small amount of mercury. Pilot data indicate that the immune system will be suppressed, brain functions impaired, and breeding severely depressed; and that these effects will be most notable in the case of early-life exposure to mercury. This could change our perception of what a "safe" level of mercury is. As the zebra finch brain is a model for understanding human speech learning this project will also give insight as to how mercury affects human health.