International Research Fellowship Program: Mechanisms for Increased Intake of Toxic Plants by Marsupial Herbivores

[0301898]索伦森国际研究奖学金计划使美国科学家和工程师能够到国外进行三至二十四个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Jennifer S. Sorensen博士与澳大利亚国立大学的William J. Foley博士和塔斯马尼亚大学的Stuart McLean博士进行为期24个月的研究。食用单一植物物种的食草哺乳动物（10种）的缺乏归因于这种饮食中存在高浓度的植物毒素。很少有实证研究对哺乳动物食草动物应对植物毒素的机制进行了研究。这个项目将包括检查毒素吸收在哺乳食草动物摄入有毒植物中的作用。通过测量摄入有毒植物桉树的专家（考拉）和通才（帚尾负鼠和山帚尾负鼠）的毒素摄入量、血液毒素浓度和毒素的粪便排泄，可以验证饮食专家比通才吸收的毒素更少的假设。据预测，专家对毒素的吸收较低，将导致更多的毒素摄入，但血液中的毒素浓度较低。PI已经在Neotoma属中发现了证据，表明专才比通才吸收更少的植物毒素，并提出的研究将通过比较不同科的专才和通才哺乳动物之间的毒素吸收和调节毒素吸收的机制来进一步扩展这些结果。

0301898SorensenThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twenty-four month research fellowship by Dr. Jennifer S. Sorensen to work with Dr. William J. Foley at the Australian National University and Dr. Stuart McLean at the University of Tasmania.The paucity of mammalian herbivores (10 species) that consume a single plant species has been attributed to the high concentrations of plant toxins present in such a diet. Little empirical work has been conducted examining the mechanisms mammalian herbivores employ to cope with plant toxins. This project will involve the examination of the role toxin absorption plays in intake of toxic plants by mammalian herbivores. The hypothesis that dietary specialists will absorb fewer toxins per unit ingested than generalists will be tested by measuring toxin intake, blood concentration of toxins, and fecal excretion of toxins by specialists (koalas) and generalists (brushtail and mountain brushtail possums) fed the toxic plant, Eucalyptus. It is predicted that lower absorption of toxins by specialists will result in greater toxin intake yet lower concentrations of toxin in the blood. The PI has found evidence within the genus Neotoma that specialists absorb fewer plant toxins than generalists and proposed research will further expand these results by comparing toxin absorption and the mechanisms that mediate toxin absorption between specialist and generalist mammalian herbivores from different families.