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The naturally occurring, non-protein amino acid N-β-methylamino-L-alanine (BMAA) is produced by cyanobacteria in many different parts of the world. Beginning with field studies performed in Guam in the early 1960s, evidence has correlated chronic exposure to low levels of BMAA in the diet to an increased risk of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and Parkinsonism-dementia. In animal model systems and in vitro bioassays, BMAA has been shown to damage neurons and induce neurodegeneration. However, inconsistency in analytical methods has led to conflicting data and controversial interpretations, and accurate analytical methods for the detection and quantification of BMAA are required. This review provides an overview of analytical methods used for BMAA analysis, including sample preparation and clean-up protocols, derivatization, chromatography, and mass spectrometry. A number of factors that should be carefully considered are identified, including solvent interactions, ion suppression, and the formation of metal adducts and complexes. Advancements in our understandings of these areas will lead to better methods for identification and quantification of BMAA in biological and environmental samples, and will help to resolve the ongoing controversy about the potential role(s) of BMAA in human health. [ABSTRACT FROM AUTHOR]

A plant regeneration system from the isolated protoplasts of Echinacea purpurea L. using an alginate solid/liquid culture is described in the chapter. Viable protoplasts were isolated from 100 mg of young leaves of 4-wk-old seedlings in an isolation mixture containing 1.0% cellulase Onozuka R-10, 0.5% pectinase, and 0.3 mol/L mannitol. After isolation and purification, the mesophyll protoplasts were embedded into 0.6% Na-alginate at the density 1 × 10−5 mL and cultured in modified Murashige and Skoog (MS) culture medium supplemented with 0.3 mol/L sucrose, 2.5 µmol/L benzylaminopurine (BA), and 5.0 µmol/L 2,4-dichlorophenoxyacetic acid (2,4-D). The visible colonies were present after 4 wk of culture. The protoplast-derived clones were transferred onto gellan gum-solidified basal medium supplemented with 1.0 µmol/L BA and 2.0 µmol/L indole-3-butyric acid (IBA) and formed compact and green calli. Shoot development was achieved by subculturing the calli onto the same basal medium supplemented with 5.0 µmol/L BA and 2.0 µmol/L IBA. Further subculture onto basal medium resulted in the regeneration of complete plantlets. [ABSTRACT FROM AUTHOR]

The transmission of signals between living cells is essential for the life of an organism as it provides the mechanism by which cells respond to external stimuli. Plants produce a wide range of phytochemicals that mediate cell function and translate environmental cues for survival and many of these are human neuroregulatory molecules. For example, the human neurotransmitter melatonin (N-acetyl-5-methoxytryptamine) is a ubiquitous, highly conserved molecule associated with timing of circadian rhythms in many organisms, including higher plants. Other compounds such as hyperforin, now isolated from several plant species, may function as serotonin transport or nonspecific cation channel activators in human brains and potentially in higher plants. A different group of neuroregulatory molecules produced by plants overstimulate human neurons, resulting in neuronal cell damage and death. Excitotoxins such as β-methylamino-L-alanine not only affect human health but are also regulatory molecules redirecting plant growth. Many fascinating questions in future research will be defining the role of neurotransmitters, neuroregulators and neurotoxins in the growth and development of plants. As newer technologies emerge, it will become possible to understand more about the role of neurological compounds in the inner workings of plant metabolism, plant environment interactions and the impact of plant neurosystems on human neurology. [ABSTRACT FROM AUTHOR]