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22-400: BMAA is a derivative of the amino acid alanine with a methylamino group on the side chain . This non-proteinogenic amino acid is classified as a polar base. BMAA is produced by cyanobacteria in marine, freshwater, and terrestrial environments. In cultured non-nitrogen-fixing cyanobacteria, BMAA production increases in a nitrogen-depleted medium. The biosynthetic pathway in cyanobacteria

44-683: A dolphin ( delphis ), propelled Cretans over the seas to make them his priests. While Delphi is actually related to the word delphus ("womb"), many etiological myths are similarly based on folk etymology (the term " Amazon ", for example). In the Aeneid (published c.  17 BC ), Virgil claims the descent of Augustus Caesar 's Julian clan from the hero Aeneas through his son Ascanius , also called Iulus. The story of Prometheus ' sacrifice trick at Mecone in Hesiod 's Theogony relates how Prometheus tricked Zeus into choosing

66-409: A population more or less likely to have an illness, condition, or disease, thus helping determine its etiology. Sometimes determining etiology is an imprecise process. In the past, the etiology of a common sailor's disease, scurvy , was long unknown. When large, ocean-going ships were built, sailors began to put to sea for long periods of time, and often lacked fresh fruit and vegetables. Without knowing

88-406: A progressive neurodegeneration in the hippocampus, including intracellular fibrillar inclusions, and impaired learning and memory as adults. BMAA has been reported to be excreted into rodent breast milk, and subsequently transferred to the suckling offspring, suggesting mothers' and cows' milk might be other possible exposure routes. Chronic dietary exposure to BMAA is now considered to be a cause of

110-588: A result of a gene-environment interaction. Degenerative locomotor diseases have been described in animals grazing on cycad species, fueling interest in a possible link between the plant and the etiology of ALS/PDC. Subsequent laboratory investigations discovered the presence of BMAA. BMAA induced severe neurotoxicity in rhesus macaques , including: There are reports that low BMAA concentrations can selectively kill cultured motor neurons from mouse spinal cords and produce reactive oxygen species . Scientists have also found that newborn rats treated with BMAA show

132-684: Is derived from the Greek word αἰτιολογία ( aitiología ), meaning "giving a reason for" (from αἰτία ( aitía )  'cause' and -λογία ( -logía )  'study of'). More completely, etiology is the study of the causes, origins, or reasons behind the way that things are, or the way they function, or it can refer to the causes themselves. The word is commonly used in medicine (pertaining to causes of disease or illness) and in philosophy , but also in physics , biology , psychology , political science , geography , cosmology , spatial analysis and theology in reference to

154-402: Is unknown, but involvement of BMAA and its structural analog 2,4-diaminobutanoic acid (2,4-DAB) in environmental iron scavenging has been hypothesized. BMAA has been found in aquatic organisms and in plants with cyanobacterial symbionts such as certain lichens , the floating fern Azolla , the leaf petioles of the tropical flowering plant Gunnera , cycads as well as in animals that eat

176-574: The amyotrophic lateral sclerosis / parkinsonism – dementia complex (ALS/PDC) that had an extremely high rate of incidence among the Chamorro people of Guam . The Chamorro call the condition lytico-bodig . In the 1950s, ALS/PDC prevalence ratios and death rates for Chamorro residents of Guam and Rota were 50–100 times that of developed countries, including the United States. No demonstrable heritable or viral factors were found for

198-521: The blood–brain barrier in rats. It takes longer to get into the brain than into other organs, but once there, it is trapped in proteins, forming a reservoir for slow release over time. Although the mechanisms by which BMAA causes motor neuron dysfunction and death are not entirely understood, current research suggests that there are multiple mechanisms of action. Acutely, BMAA can act as an excitotoxin on glutamate receptors, such as NMDA , calcium-dependent AMPA , and kainate receptors. The activation of

220-536: The metabotropic glutamate receptor 5 is believed to induce oxidative stress in the neuron by depletion of glutathione . BMAA can be misincorporated into nascent proteins in place of L -serine , possibly causing protein misfolding and aggregation, both hallmarks of tangle diseases , including Alzheimer's disease , Parkinson's disease , amyotrophic lateral sclerosis (ALS), progressive supranuclear palsy (PSP), and Lewy body disease . In vitro research has shown that protein association of BMAA may be inhibited in

242-502: The Wikimedia System Administrators, please include the details below. Request from 172.68.168.133 via cp1102 cp1102, Varnish XID 547316523 Upstream caches: cp1102 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 05:55:10 GMT Etiology Etiology ( / ˌ iː t i ˈ ɒ l ə dʒ i / ; alternatively spelled aetiology or ætiology ) is the study of causation or origination. The word

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264-447: The causes or origins of various phenomena . In the past, when many physical phenomena were not well understood or when histories were not recorded, myths often arose to provide etiologies. Thus, an etiological myth, or origin myth , is a myth that has arisen, been told over time or written to explain the origins of various social or natural phenomena. For example, Virgil 's Aeneid is a national myth written to explain and glorify

286-489: The disease, and a subsequent decline of ALS/PDC after 1963 on Guam led to the search for responsible environmental agents. The use of flour made from cycad seed ( Cycas micronesica ) in traditional food items decreased as that plant became rarer and the Chamorro population became more Americanized following World War II. Cycads harbor symbiotic cyanobacteria of the genus Nostoc in specialized roots which push up through

308-512: The fleshy covering of cycad seeds, including flying foxes . High concentrations (144 to 1836 ng/mg of flesh) of BMAA are present in shark fins. Because BMAA is a neurotoxin, consumption of shark fin soup and cartilage pills therefore may pose a health risk. The toxin can be detected via several laboratory methods, including liquid chromatography , high-performance liquid chromatography , mass spectrometry , amino acid analyzer , capillary electrophoresis , and NMR spectroscopy . BMAA can cross

330-462: The lack of vitamin C in a sailor's diet. The following are examples of intrinsic factors: An etiological myth, or origin myth, is a myth intended to explain the origins of cult practices, natural phenomena, proper names and the like. For example, the name Delphi and its associated deity, Apollon Delphinios , are explained in the Homeric Hymn which tells of how Apollo, in the shape of

352-422: The leaf litter into the light; these cyanobacteria produce BMAA. In addition to eating traditional food items from cycad flour directly, BMAA may be ingested by humans through biomagnification . Flying foxes , a Chamorro delicacy , forage on the fleshy seed covering of cycad seeds and concentrate the toxin in their bodies. Twenty-four specimens of flying foxes from museum collections were tested for BMAA, which

374-547: The origins of the Roman Empire . In theology , many religions have creation myths explaining the origins of the world or its relationship to believers. In medicine, the etiology of an illness or condition refers to the frequent studies to determine one or more factors that come together to cause the illness. Relatedly, when disease is widespread, epidemiological studies investigate what associated factors, such as location, sex, exposure to chemicals, and many others, make

396-459: The precise cause, Captain James Cook suspected scurvy was caused by the lack of vegetables in the diet. Based on his suspicion, he forced his crew to eat sauerkraut , a cabbage preparation, every day, and based upon the positive outcomes, he inferred that it prevented scurvy, even though he did not know precisely why. It took about another two hundred years to discover the precise etiology;

418-492: The presence of excess L -serine. A study performed in 2015 with vervet monkeys ( Chlorocebus sabaeus ) in St. Kitts, which are homozygous for the apoE4 gene (a condition which in humans is a risk factor for Alzheimer's disease), found that vervets that were administered BMAA orally developed hallmark histopathology features of Alzheimer's disease, including amyloid beta plaques and neurofibrillary tangle accumulation. Vervets in

440-707: The role of BMAA as an environmental factor in neurodegenerative disease continued. Safe and effective ways of treating ALS patients with L -serine that has been found to protect non-human primates from BMAA-induced neurodegeneration, have been goals of clinical trials conducted by the Phoenix Neurological Associates and the Forbes/Norris ALS/MND clinic and sponsored by the Institute for Ethnomedicine. Derivative (chemistry) Too Many Requests If you report this error to

462-624: The trial fed smaller doses of BMAA were found to have correlative decreases in these pathology features. Additionally, vervets that were co-administered BMAA with serine were found to have 70% less beta-amyloid plaques and neurofibrillary tangles than those administered BMAA alone, suggesting that serine may be protective against the neurotoxic effects of BMAA. This experiment represents the first in-vivo model of Alzheimer's disease that features both beta-amyloid plaques and hyperphosphorylated tau protein. This study also demonstrates that BMAA, an environmental toxin, can trigger neurodegenerative disease as

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484-528: Was found in large concentrations in the flying foxes from Guam. As of 2021 studies continued examining BMAA biomagnification in marine and estuarine systems and its possible impact on human health outside of Guam. Studies on human brain tissue of ALS/PDC, ALS, Alzheimer's disease , Parkinson's disease, Huntington's disease , and neurological controls indicated that BMAA is present in non-genetic progressive neurodegenerative disease, but not in controls or genetic-based Huntington's disease. As of 2021 research into

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