α-Amino-β-methylaminopropionic acid, a new amino acid from seeds of Cycas circinalis

Vega, Armando; Bell, E. A.

doi:10.1016/s0031-9422(00)86018-5

Cited by 292 publications

(150 citation statements)

References 2 publications

Supporting

Mentioning

141

Contrasting

Unclassified

Order By: Relevance

“…Brenner et al, 2000). Thorough sampling of the cycads and related groups for the presence of BMAA subsequent to its discovery in Cycas circinalis (Vega and Bell, 1967) tested and confirmed the hypothesis that this compound is unique to the cycads, resulting in the focus on that group by the current genomic investigations of cycads mentioned above.…”

Section: Back To Basicsmentioning

confidence: 90%

Plant Systematics in the Age of Genomics

Daly

2001

Plant Physiology

View full text Add to dashboard Cite

As plant biologists enter a new era in which comparative genomics promises to address fundamental questions in botany, such as unraveling metabolic and regulatory networks, the inestimable value and usefulness of robust systematic studies quickly become clear. In simplest terms, systematic studies can indicate which genomes in the plant kingdom to search, sample, and study for the answers to questions relating to the evolution of chemical and physical structures and their synthesis or ontogeny. After several model and crop species have been sequenced, the next phase of plant genomics will necessarily build on new phylogenies that are greatly assisted by molecular techniques and whose interpretation and applications will be guided by "traditional" botanical knowledge.Plant systematics was long considered to be an "artful science," but well before the application of molecular techniques to systematics, semisubjective authority was supplanted by rapidly developing analytical methods and the computers that run them. In the age of genomics, the art of modern plant systematics lies in its applications and its links to other disciplines; conversely, the applications of genomics to an expanding array of plant species will be grounded in plant systematics, itself still based largely on field work and knowing the plants.Much is new-and much is not-for plant systematics in the age of genomics. Molecular techniques have introduced vast and numerous independent data sets, and there are continual advances in preparing DNA, sequencing genes, aligning sequences, and designing software for interpreting the data. As a consequence of this increased accessibility, mainstream plant systematics has been able to incorporate molecular approaches, which no longer occupy a separate domain but rather constitute part of the normal repertoire of skills for systematic botanists.The special usefulness of molecular approaches in analyzing phylogenetic relationships at higher ranks has resulted in still unresolved but clearly better and dramatically new classifications, discussed below. These developments, coupled with other advances in phylogenetic analysis, now place systematics in a key position among other disciplines in biology, with increasingly diverse and powerful applications in investigations of biosynthetic and developmental pathways, natural products, origins and migrations of evolutionary lineages, and conservation. Whether it occupies the hub or spokes, more than ever plant systematics is needed to make the genomics wheel roll.The biggest non-news is that molecular techniques have in fact not revolutionized methodologies in systematics. Instead, molecular data have rather rapidly been accommodated in existing analytical methods whose revolution-cladistics-had come and for some time had been the new order (Schuh, 2000). Once computers could be harnessed to execute complex pattern analysis and resample data thousands of times for statistical rigor, phylogenetic systematics or cladistics had overruled the authority represented by a f...

show abstract

Section: Back To Basicsmentioning

confidence: 90%

Plant Systematics in the Age of Genomics

Daly

2001

Plant Physiology

View full text Add to dashboard Cite

show abstract

“…In species of the Cycadaceae, BMAA is detected at high levels (milligram BMAA/gram of tissue) (Vega and Bell, 1967;Duncan et al, 1989;Pan et al, 1997). The presence of high levels of BMAA in such tissues has led some researchers to suggest that BMAA may act as a toxin against predators (Ladd et al, 1993).…”

Section: Discussionmentioning

confidence: 99%

Arabidopsis Mutants Resistant to S(+)-β-Methyl-α, β-Diaminopropionic Acid, a Cycad-Derived Glutamate Receptor Agonist

et al. 2000

View full text Add to dashboard Cite

Ionotropic glutamate receptors (iGluRs) are ligand-gated ion channels that are the predominant neuroreceptors in the mammalian brain. Genes with high sequence similarity to animal iGluRs have been identified in Arabidopsis. To understand the role of Arabidopsis glutamate receptor-like (AtGLR) genes in plants, we have taken a pharmacological approach by examining the effects of BMAA [S(ϩ)-␤-methyl-␣, ␤-diaminopropionic acid], a cycad-derived iGluR agonist, on Arabidopsis morphogenesis. When applied to Arabidopsis seedlings, BMAA caused a 2-to 3-fold increase in hypocotyl elongation and inhibited cotyledon opening during early seedling development. The effect of BMAA on hypocotyl elongation is light specific. Furthermore, BMAA effects on early morphogenesis of Arabidopsis can be reversed by the simultaneous application of glutamate, the native iGluR agonist in animals. To determine the targets of BMAA action in Arabidopsis, a genetic screen was devised to isolate Arabidopsis mutants with a BMAA insensitive morphology (bim). When grown in the light on BMAA, bim mutants exhibited short hypocotyls compared with wild type. bim mutants were grouped into three classes based on their morphology when grown in the dark in the absence of BMAA. Class-I bim mutants have a normal, etiolated morphology, similar to wild-type plants. Class-II bim mutants have shorter hypocotyls and closed cotyledons when grown in the dark. Class-III bim mutants have short hypocotyls and open cotyledons when grown in the dark, resembling the previously characterized constitutively photomorphogenic mutants (cop, det, fus, and shy). Further analysis of the bim mutants should help define whether plant-derived iGluR agonists target glutamate receptor signaling pathways in plants.

show abstract

“…The elimination of external soil-borne bacteria was ensured by surface sterilization of cycad root tissues in a solution of 70% (vol͞vol) ethanol for 3 min followed by a 30-min immersion in 1.6% (vol͞vol) of a 5.4% stock solution of sodium hypochlorite with two drops of surfactant and three sequential washes with sterile deionized water before culture onto standard BG-11 medium, pH 7.1, solidified with gellam gum (Sigma). Cultures were maintained in a controlled-environment room with a 16-h photoperiod at a light intensity of 35-45 mol͞m 2 per s and temperatures of 25-30°C for a period of 4 months with monthly subculture and sampling for analysis of BMAA. His- tological characterizations were used to verify cyanobacterial culture identity and purity.…”

Section: Methodsmentioning

confidence: 99%

A mechanism for slow release of biomagnified cyanobacterial neurotoxins and neurodegenerative disease in Guam

Murch

Cox

Banack

2004

Proc. Natl. Acad. Sci. U.S.A.

363

326

View full text Add to dashboard Cite

As root symbionts of cycad trees, cyanobacteria of the genus Nostoc produce ␤-methylamino-L-alanine (BMAA), a neurotoxic nonprotein amino acid. The biomagnification of BMAA through the Guam ecosystem fits a classic triangle of increasing concentrations of toxic compounds up the food chain. However, because BMAA is polar and nonlipophilic, a mechanism for its biomagnification through increasing trophic levels has been unclear. We report that BMAA occurs not only as a free amino acid in the Guam ecosystem but also can be released from a bound form by acid hydrolysis. After first removing free amino acids from tissue samples of various trophic levels (cyanobacteria, root symbioses, cycad seeds, cycad flour, flying foxes eaten by the Chamorro people, and brain tissues of Chamorros who died from amyotrophic lateral sclerosis͞ Parkinsonism dementia complex), we then hydrolyzed the remaining fraction and found BMAA concentrations increased 10-to 240-fold. This bound form of BMAA may function as an endogenous neurotoxic reservoir, accumulating and being transported between trophic levels and subsequently being released during digestion and protein metabolism. Within brain tissues, the endogenous neurotoxic reservoir can slowly release free BMAA, thereby causing incipient and recurrent neurological damage over years or even decades, which may explain the observed long latency period for neurological disease onset among the Chamorro people. The presence of BMAA in brain tissues from Canadian patients who died of Alzheimer's disease suggests that exposure to cyanobacterial neurotoxins occurs outside of Guam.biomagnification ͉ cyanobacteria ͉ cycad ͉ symbiosis ͉ ALS͞PDC

show abstract

α-Amino-β-methylaminopropionic acid, a new amino acid from seeds of Cycas circinalis

Cited by 292 publications

References 2 publications

Plant Systematics in the Age of Genomics

Plant Systematics in the Age of Genomics

Arabidopsis Mutants Resistant to S(+)-β-Methyl-α, β-Diaminopropionic Acid, a Cycad-Derived Glutamate Receptor Agonist

A mechanism for slow release of biomagnified cyanobacterial neurotoxins and neurodegenerative disease in Guam

Contact Info

Product

Resources

About