Chemistry of Natural Non-Protein Amino Acids

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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.