Food Chain Magnification of Marine Toxins

在这项研究中，位于马诺阿的夏威夷大学的研究人员将研究夏威夷珊瑚礁的植物群和动物群中两种神经毒素的生物放大作用。毒素，β-N-甲基氨基-L-丙氨酸（BMAA），一种低分子量（约。120 amu）氨基酸，和雪卡毒素（CTX），大分子量（约120 amu）氨基酸。1，200 amu）聚醚被选择用于研究，因为它们的化学性质不同，因此可能具有非常不同的生物放大模式。这项工作将利用在特定氨基酸内的氮分馏的研究和解释的最新进展，以确定一个生物体在食物网中相对于第一营养级的位置。源氨基酸（甘氨酸、赖氨酸、苯丙氨酸、丝氨酸、苏氨酸和酪氨酸）记录了食物网底部氮源的d15 N值，营养氨基酸（丙氨酸、天冬氨酸、谷氨酸、异亮氨酸、亮氨酸、脯氨酸和缬氨酸）反映了消费者的营养水平。将在（1）简单线性食物链和（2）非结构化食物网的框架内分析鱼类和贝类组织中营养氨基酸和源氨基酸的d15 N值之间的差异与毒素浓度之间的关系，以确定哪种理论构建与实验结果最一致。其他研究将侧重于CTX和BMAA生产的环境控制程度，以及鱼类和贝类中这些毒素浓度的差异在多大程度上反映了摄食/养殖环境的差异。消费者生物的生理学或生产者水平物种之间的变异性。拟议的工作反映了实验观察和理论理解的整合，以深入了解调节生物的过程。毒素通过海洋食物网的移动。在实验上，使用特定化合物的15 N分析源和营养氨基酸，以确定一个有机体？的位置在食物网是一个重要的最新进展，和应用非结构化的食物网理论或其变种可能会证明有必要解释模式的生物放大在复杂的食物网，珊瑚礁生物群落的特点。由于这些食物网的复杂性绝不是异常的，从这项研究中获得的见解可能具有广泛的适用性，海洋系统的食物网离开严格的线性。拟议工作的更广泛影响包括：（1）为参与夏威夷大学（UH）全球环境科学专业的高级研究项目提供资金，（2）包括NSF REU学生（C-MORE微生物海洋学研究经验-提案待定），（3）200美元，000的承诺，由呃副校长的研究购买四极质谱仪与适当的APCI/ESI探针硬件，以便于确定珊瑚礁植物群和动物群提取物中雪卡毒素和相关毒素的结构，以及（4）出版针对本科生和研究生的教育材料，并将这些材料纳入夏威夷大学海洋学系提供的课程。

In this study, researchers at the University of Hawaii at Manoa will examine the biological magnification of two neurotoxins in the flora and fauna of Hawaiian coral reefs. The toxins, beta-N-methylamino-L-alanine (BMAA), a low molecular weight (ca. 120amu) amino acid, and ciguatoxin (CTX), a large molecular weight (ca. 1,200 amu) polyether, were selected for study because of their different chemical natures and hence potentially very different biological magnification patterns. The work will take advantage of recent advances in the study and interpretation of nitrogen fractionation within specific amino acids to identify an organism's position in the food web relative to the first trophic level. Source amino acids (glycine, lysine, phenylalanine, serine, threonine and tyrosine) record the d15N value of the source of nitrogen at the base of the food web, and trophic amino acids (alanine, aspartic acid, glutamic acid, isoleucine, leucine, proline and valine) reflect the trophic level of the consumer. The relationship between the difference between the d15N values of trophic and source amino acids and toxin concentrations in the tissues of fish and shellfish will be analyzed within the framework of (1) a simple linear food chain and (2) an unstructured food web to determine which theoretical construct is most consistent with experimental results. Additional studies will focus on the degree of environmental control of CTX and BMAA production and the extent to which differences in the concentrations of these toxins in fish and shellfish reflect differences in the feeding/physiology of consumer organisms or variability between species at the producer level.The proposed work reflects the integration of experimental observations and theoretical understanding to gain insight into the processes that regulate the movement of toxins through marine food webs. Experimentally the use of compound-specific 15N analyses of source and trophic amino acids to determine an organism?s position in a food web is an important recent advancement, and application of unstructured food web theory or variations thereof will likely prove necessary to explain the patterns of biological magnification in the complex food webs that characterize coral reef biological communities. Since the complexity of these food webs is by no means anomalous, insights gained from this study may have broad applicability to marine systems where food webs depart from strict linearity. The broader impacts of the proposed work include (1) funding for the participation of University of Hawaii (UH) Global Environmental Science majors working on their senior research projects, (2) the inclusion of NSF REU students (C-MORE Research Experiences in Microbial Oceanography - proposal pending), (3) a $200,000 commitment by the UH vice chancellor for research to purchase a quadrupole mass spectrometer with the appropriate APCI/ESI probe hardware to facilitate the determination of the structures of ciguatoxins and related toxins in extracts from coral reef flora and fauna, and (4) the publication of educational materials that target both undergraduate and graduate students, and the inclusion of these material into courses offered by the Department of Oceanography at the University of Hawaii.