International Research Fellowship Program: Profiling Marine Herbivore Gene Expression in Response to Algal Chemical Defenses

[0754319]惠伦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9至24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。该奖项将支持加州大学圣巴巴拉分校的Kristen E. Whalen博士与澳大利亚南威尔士大学的Peter Steinberg博士以及加州大学圣巴巴拉分校的Gretchen Hofmann博士共同开展为期24个月的研究。将分子工具与传统方法结合起来研究海洋藻类与草食动物的相互作用，在化学生态学领域具有相当大的前景。尽管在确定藻类化学防御的多样性、浓度和分布及其对海洋食草动物的影响方面取得了巨大进展，但很少有研究解决这些食草动物对化学防御食物耐受性差异的直接机制。部分问题是我们几乎没有关于海洋食草动物调节这种相互作用的生理反应的信息。幸运的是，基因组技术的最新进展将为细胞和最终生物体如何耐受和响应环境化学压力的机制基础提供详细和前所未有的观点。使用DNA微阵列的转录组分析等技术将允许对数千个基因的表达进行平行分析，并提供对饮食化合物作出反应的基因调控的完整图景。随着紫海胆基因组最近的完成和注释，负责调节藻类化学耐受的基因首次可以在海洋食草动物中被鉴定出来。该项目的中心目标是开发海胆微阵列，作为了解海洋食草动物生理和对饮食化学应激源抗性的更广泛方面的工具。一个寡核苷酸阵列将设计和构建超过2000个基因重要的外源解毒/外排，信号转导，营养代谢和化学接受。这种定制设计的海胆阵列将用于分析澳大利亚海胆（Heliocidaris erythrogramma）的基因表达，以响应化学上不同的大藻饮食。转录组分析将识别目标基因，其时间表达将通过实时定量PCR进一步评估。此外，通过转录组分析鉴定的基因可以用于藻类化合物-蛋白质相互作用的其他生化表征。PI预计这项工作将增加我们对影响藻类与草食动物相互作用的潜在生化机制的了解，从而更全面地了解海洋消费者对饮食化学应激源的反应和饮食选择的生化基础。

0754319WhalenThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine 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. Kristen E. Whalen, University of California, Santa Barbara, to work with Dr. Peter Steinberg at the University of South Wales in Australia, and with Dr. Gretchen Hofmann at the University of California, Santa Barbara.The marriage between molecular tools and traditional methods for the study of marine algal-herbivore interactions holds considerable promise for the field of chemical ecology. Despite tremendous progress in identifying the diversity, concentrations and distribution of algal chemical defenses and their impact on marine herbivores, few studies have addressed the proximate mechanisms underlying the profound variation in tolerance among these herbivores for their chemically defended foods. Part of the problem is we have virtually no information on the physiological responses of marine herbivores mediating this interaction. Fortunately, recent advances in genomic technology will provide a detailed and unprecedented view of the mechanistic underpinnings of how cells and ultimately organisms tolerate and respond to environmental chemical stresses. Techniques such as transcriptome profiling using DNA microarrays will allow for the parallel analysis of the expression of thousands of genes and provide a complete picture of gene regulation occurring in response to dietary compounds. With the recent completion and annotation of the purple sea urchin genome, genes responsible for mediating tolerance of algal chemistry can, for the first time, be identified in a marine herbivore. The central objective of this project is to develop the sea urchin microarray as a tool for understanding broader aspects of marine herbivore physiology and resistance to dietary chemical stressors. An oligonucleotide array will be designed and constructed targeting over 2000 genes important in xenobiotic detoxification/efflux, signal transduction, nutrient metabolism and chemoreception. This custom designed sea urchin array will be used to profile gene expression in the Australian urchin Heliocidaris erythrogramma, in response to chemically diverse macroalgal diets. Transcriptome profiling will identify target genes whose temporal expression will be further assessed by real-time quantitative PCR. Furthermore, genes identified by transcriptome profiling can be targeted for additional biochemical characterization of algal compound-protein interactions. The PI anticipates this work will add volumes to our knowledge of the underlying biochemical mechanisms influencing algal-herbivore interactions, leading to a more complete understanding of marine consumer response to dietary chemical stressors and the biochemical basis of diet selection.