Chemistry of Natural Non-Protein Amino Acids

每一片植物都含有大约35000种不同的植物化学物质，其中绝大多数是次生的或专门的代谢物，至今仍未被识别。一杯普通的咖啡含有大约8400种不同的植物化学物质，而蔓越莓含有大约28000种，一片叶子含有多达40000种。在这些样本中，只有大约1100种植物化学物质被完全鉴定出来。我们估计，一个普通人每天的饮食中含有20万种未知的植物化学物质。色谱法和质谱法的最新进展使检测和定量具有更高的准确性和精密度，但也可能产生误导或错误的结果。我的研究使用质谱分析植物化学物质。我的HQP积极致力于开发准确有效的分析方法和统计工具，以进行准确的鉴定和量化。

Each piece of a plant contains > 35,000 distinct phytochemicals, and the vast majority of these are secondary or specialized metabolites that remain unidentified. An average cup of coffee has about 8,400 distinct phtyochemicals while a cranberry has about 28,000 and a piece of leaf can have up to 40,000. Only about 1,100 phytochemicals have been fully identified in any of these samples. We estimated that an average person's diet contains > 200,000 unknown phytochemicals per day. Recent advances in chromatography and mass spectrometry have enabled detection and quantification with greater accuracy and precision but can also give misleading or false results. My research uses mass spectrometry to analyze plant chemicals. My HQP are actively engaged in developing accurate validated analytical methods and statistical tools for accurate identification and quantification. The proposed research program will continue our investigation of a set of non-protein amino acids produced by cyanobacterial blooms and accumulated through ecosystems and food webs. N--methylamino-L-alanine (BMAA) is a neurotoxic non-protein amino acid that has been known since the 1960s and has recently been associated as a potential causal agent of amyotrophic lateral sclerosis (ALS) and other progressive neurodegenerative diseases. BMAA is produced by algal blooms in lakes and oceans where it enters food chain through natural associations with some plants, irrigation of crop plants with contaminated waters, or accumulation through trophic levels of ecosystems. For example, BMAA produced by cyanobacteria in Guam was accumulated by the seeds of cycad trees, the animals that fed on the cycad seeds and the humans who consumed both the animals and a flour made from cycad seeds. The indigenous population of Guam, the Chamorro, suffered from an epidemic of neurodegenerative disease with symptoms similar to ALS, Alzheimer's and Parkinson's diseases related to exposure BMAA in their traditional food web. Understanding how BMAA is produced and accumulated is essential to recognizing and minimizing the human risks of exposure. My HQP develop methods to detect and quantify BMAA and other potentially neurotoxic non-protein amino acids in ecosystems and food webs. To date, we have developed accurate methods and investigated natural food ecosystems in 6 countries including Canada, quantified BMAA in Lake Winnipeg and made significant progress in understanding the mechanisms of neurotoxicity. Our proposed research program will improve food safety through reduction of naturally-occurring toxins in the food chain and understand the chemistry, metabolism, and environmental importance of natural non-protein amino acids.