Toxicity of cycads

Whiting, Marjorie Grant

doi:10.1007/bf02860136

Cited by 273 publications

(151 citation statements)

References 32 publications

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“…Without such procedures, maize-dependent populations would face widespread malnutrition, including niacin deficiency (pellagra) and a lack of certain essential amino acids. Similarly, elaborate processing techniques protect foraging and horticultural populations (Whiting 1963;Heizer 1978;Beck 1992;Wilson & Dufour 2002) from the toxins present in otherwise valuable food sources (e.g. acorns, cycads, cassava).…”

Section: Theoretical Backgroundmentioning

confidence: 99%

The evolution of cultural adaptations: Fijian food taboos protect against dangerous marine toxins

2010

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The application of evolutionary theory to understanding the origins of our species' capacities for social learning has generated key insights into cultural evolution. By focusing on how our psychology has evolved to adaptively extract beliefs and practices by observing others, theorists have hypothesized how social learning can, over generations, give rise to culturally evolved adaptations. While much field research documents the subtle ways in which culturally transmitted beliefs and practices adapt people to their local environments, and much experimental work reveals the predicted patterns of social learning, little research connects real-world adaptive cultural traits to the patterns of transmission predicted by these theories. Addressing this gap, we show how food taboos for pregnant and lactating women in Fiji selectively target the most toxic marine species, effectively reducing a woman's chances of fish poisoning by 30 per cent during pregnancy and 60 per cent during breastfeeding. We further analyse how these taboos are transmitted, showing support for cultural evolutionary models that combine familial transmission with selective learning from locally prestigious individuals. In addition, we explore how particular aspects of human cognitive processes increase the frequency of some non-adaptive taboos. This case demonstrates how evolutionary theory can be deployed to explain both adaptive and non-adaptive behavioural patterns.

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Section: Theoretical Backgroundmentioning

confidence: 99%

The evolution of cultural adaptations: Fijian food taboos protect against dangerous marine toxins

2010

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“…Marjorie Whiting was the first to propose that cycads could be responsible for Guam's dementia [5]. The subsequent search for a neurotoxic compound in cycads lead to the identification of a novel non-protein amino acid called BMAA (beta-methylamino-L-alanine) [8].…”

Section: Molecular Studies In Cycadsmentioning

confidence: 99%

“…The 'Zamia staggers' is a condition of ataxia in the hind-limbs of cattle and sheep that graze on cycads [2,4]. More mysterious is the heightened presence of Alzheimer's and Parkinsonian's dementia among people that eat cycads [5]. This disease, known as 'Guam's dementia', has been linked to the presence of neurotoxic compounds synthesized by cycads [6 -8].…”

mentioning

confidence: 99%

Cycads: evolutionary innovations and the role of plant-derived neurotoxins

Brenner

Stevenson

Twigg

2003

Trends in Plant Science

153

137

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“…Then, as now, the strongest epidemiological link was to local consumption by the native Chamorro people of the starchy gametophyte of the indigenous cycad tree (Cycas micronesica) (Whiting 1963;Kurland 1988;Borenstein et al 2007;Galasko et al 2007). …”

Section: Introductionmentioning

confidence: 99%

Chronic Exposure to Dietary Sterol Glucosides is Neurotoxic to Motor Neurons and Induces an ALS–PDC Phenotype

Tabata

Wilson

et al. 2008

Neuromol Med

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Epidemiological studies of the Guamanian variants of amyotrophic lateral sclerosis (ALS) and parkinsonism, amyotrophic lateral sclerosis-parkinsonism dementia complex (ALS-PDC), have shown a positive correlation between consumption of washed cycad seed flour and disease occurrence. Previous in vivo studies by our group have shown that the same seed flour induces ALS and PDC phenotypes in out bred adult male mice. In vitro studies using isolated cycad compounds have also demonstrated that several of these are neurotoxic, specifically, a number of water insoluble phytosterol glucosides of which β-sitosterol β-D-glucoside (BSSG) forms the largest fraction. BSSG is neurotoxic to motor neurons and other neuronal populations in culture. The present study shows that an in vitro hybrid motor neuron (NSC-34) culture treated with BSSG undergoes a dose-dependent cell loss. Surviving cells show increased expression of HSP70, decreased cytosolic heavy neurofilament expression, and have various morphological abnormalities. CD-1 mice fed mouse NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript chow pellets containing BSSG for 15 weeks showed motor deficits and motor neuron loss in the lumbar and thoracic spinal cord, along with decreased glutamate transporter labelling, and increased glial fibrillary acid protein reactivity. Other pathological outcomes included increased caspase-3 labelling in the striatum and decreased tyrosine-hydroxylase labelling in the striatum and substantia nigra. C57BL/6 mice fed BSSG-treated pellets for 10 weeks exhibited progressive loss of motor neurons in the lumbar spinal cord that continued to worsen even after the BSSG exposure ended. These results provide further support implicating sterol glucosides as one potential causal factor in the motor neuron pathology previously associated with cycad consumption and ALS-PDC.

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Toxicity of cycads

Cited by 273 publications

References 32 publications

The evolution of cultural adaptations: Fijian food taboos protect against dangerous marine toxins

The evolution of cultural adaptations: Fijian food taboos protect against dangerous marine toxins

Cycads: evolutionary innovations and the role of plant-derived neurotoxins

Chronic Exposure to Dietary Sterol Glucosides is Neurotoxic to Motor Neurons and Induces an ALS–PDC Phenotype

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