Plants, selenium and human health

Ellis, Danielle R.; Salt, David E.

doi:10.1016/s1369-5266(03)00030-x

Cited by 437 publications

(282 citation statements)

References 53 publications

Supporting

Mentioning

275

Contrasting

Unclassified

Order By: Relevance

“…For example, monomethylselenol and its precursors methyl-selenocysteine (MeSeCys) have been identified to be the key anticarcinogenic Se species (14,15). Se speciation in Se-enriched rice had been studied, and selenomethionine (SeMet) was confirmed to be the major Se species (16).…”

Section: Introductionmentioning

confidence: 99%

Distribution and Translocation of Selenium from Soil to Grain and Its Speciation in Paddy Rice (Oryza sativa L.)

Sun

Liu

Williams

et al. 2010

Environ. Sci. Technol.

111

View full text Add to dashboard Cite

Selenium, an essential micronutrient for humans, is insufficient in dietary intake for millions of people worldwide. Rice as the most popular staple food in the world is one of the dominant selenium (Se) sources for people. The distribution and translocation of Se from soil to grain were investigated in a Serich environment in this study. The Se levels in soils ranged widely from 0.5 to 47.7 mg kg -1 . Selenium concentration in rice bran was 1.94 times higher than that in corresponding polished rice. The total Se concentrations in the rice fractions were in the following order: straw > bran > whole grain > polished rice > husk. Significant linear relationships between different rice fractions were observed with each other, and Se in the soil has a linear relationship with different rice fractions as well. Se concentration in rice can easily be predicted by soil Se concentrations or any rice fractions and vice versa according to their linear relationships. In all rice samples for Se speciation, SeMet was the major Se species, followed by MeSeCys and SeCys. The average percentage for SeMet (82.9%) and MeSeCys (6.2%) was similar in the range of total Se from 2.2 to 8.4 mg kg -1 tested. The percentage of SeCys decreased from 6.3 to 2.8%, although its concentration elevated with the increase in total Se in rice. This could be due to the fact that SeCys is the precursor for the formation of other organic Se compounds. The information obtained may have considerable significance for assessing translocation and accumulation of Se in plant.

show abstract

Section: Introductionmentioning

confidence: 99%

Distribution and Translocation of Selenium from Soil to Grain and Its Speciation in Paddy Rice (Oryza sativa L.)

Sun

Liu

Williams

et al. 2010

Environ. Sci. Technol.

111

View full text Add to dashboard Cite

show abstract

“…In particular monomethylselenol and its precursorsmethyl-selenocysteine(Se-MeSeCys)andR-glutamylderivatives have been suggested to be the key anticarcinogenic Se species (18)(19)(20). To date, speciation of Se in rice has not been investigated with in situ techniques such as X-ray absorption near edge structure (XANES).…”

Section: Introductionmentioning

confidence: 99%

Selenium Characterization in the Global Rice Supply Chain

Williams

Lombi

Sun

et al. 2009

Environ. Sci. Technol.

195

133

View full text Add to dashboard Cite

For up to 1 billion people worldwide, insufficient dietary intake of selenium (Se) is a serious health constraint. Cereals are the dominant Se source for those on low protein diets, as typified by the global malnourished population. With crop Se content constrained largely by underlying geology, regional soil Se variations are often mirrored by their locally grown staples. Despite this, the Se concentrations of much of the world's rice, the mainstay of so many, is poorly characterized, for both total Se content and Se speciation. In this study, 1092 samples of market sourced polished rice were obtained. The sampled rice encompassed dominant rice producing and exporting countries. Rice from the U.S. and India were found to be the most enriched, while mean average levels were lowest in Egyptian rice: ∼32-fold less than their North American equivalents. By weighting country averages by contribution to either global production or export, modeled baseline values for both were produced. Based on a daily rice consumption of 300 g day -1 , around 75% of the grains from the production and export pools would fail to provide 70% of daily recommended Se intakes. Furthermore, Se localization and speciation characterization using X-ray fluorescence (µ-XRF) and X-ray absorption near edge structure (µ-XANES) techniques were investigated in a Se-rich sample. The results revealed that the large majority of Se in the endosperm was present in organic forms.

show abstract

“…Plants take up selenate (SeO 4 22 ), the most abundant bioavailable form of Se in soils, via sulfate transporters in roots (Shibagaki et al, 2002;Ellis and Salt, 2003). After uptake, selenate is thought to be transported into leaves and chloroplasts (Leustek, 2002).…”

mentioning

confidence: 99%

“…Indistinguishable to most S enzymes, Se can be found in most S-containing metabolites (Leustek, 2002). In chloroplasts, the S assimilation pathway first reduces selenate to selenite, then selenide, which is enzymatically incorporated into selenocysteine (SeCys) and selenomethionine (SeMet; for review, see Terry et al, 2000;Ellis and Salt, 2003;Sors et al, 2005b). These two seleno-amino acids can be misincorporated into proteins, replacing Cys and Met, which causes Se toxicity Shrift, 1981, 1982;Stadtman, 1996).…”

mentioning

confidence: 99%

Molecular Mechanisms of Selenium Tolerance and Hyperaccumulation in Stanleya pinnata

Freeman

Tamaoki²,

Stushnoff³

et al. 2010

Plant Physiol.

220

187

View full text Add to dashboard Cite

The molecular mechanisms responsible for selenium (Se) tolerance and hyperaccumulation were studied in the Se hyperaccumulator Stanleya pinnata (Brassicaceae) by comparing it with the related secondary Se accumulator Stanleya albescens using a combination of physiological, structural, genomic, and biochemical approaches. S. pinnata accumulated 3.6-fold more Se and was tolerant to 20 mM selenate, while S. albescens suffered reduced growth, chlorosis and necrosis, impaired photosynthesis, and high levels of reactive oxygen species. Levels of ascorbic acid, glutathione, total sulfur, and nonprotein thiols were higher in S. pinnata, suggesting that Se tolerance may in part be due to increased antioxidants and up-regulated sulfur assimilation. S. pinnata had higher selenocysteine methyltransferase protein levels and, judged from liquid chromatography-mass spectrometry, mainly accumulated the free amino acid methylselenocysteine, while S. albescens accumulated mainly the free amino acid selenocystathionine. S. albescens leaf x-ray absorption near-edge structure scans mainly detected a carbon-Se-carbon compound (presumably selenocystathionine) in addition to some selenocysteine and selenate. Thus, S. albescens may accumulate more toxic forms of Se in its leaves than S. pinnata. The species also showed different leaf Se sequestration patterns: while S. albescens showed a diffuse pattern, S. pinnata sequestered Se in localized epidermal cell clusters along leaf margins and tips, concentrated inside of epidermal cells. Transcript analyses of S. pinnata showed a constitutively higher expression of genes involved in sulfur assimilation, antioxidant activities, defense, and response to (methyl)jasmonic acid, salicylic acid, or ethylene. The levels of some of these hormones were constitutively elevated in S. pinnata compared with S. albescens, and leaf Se accumulation was slightly enhanced in both species when these hormones were supplied. Thus, defense-related phytohormones may play an important signaling role in the Se hyperaccumulation of S. pinnata, perhaps by constitutively up-regulating sulfur/Se assimilation followed by methylation of selenocysteine and the targeted sequestration of methylselenocysteine.

show abstract

Plants, selenium and human health

Cited by 437 publications

References 53 publications

Distribution and Translocation of Selenium from Soil to Grain and Its Speciation in Paddy Rice (Oryza sativa L.)

Distribution and Translocation of Selenium from Soil to Grain and Its Speciation in Paddy Rice (Oryza sativa L.)

Selenium Characterization in the Global Rice Supply Chain

Molecular Mechanisms of Selenium Tolerance and Hyperaccumulation in Stanleya pinnata

Contact Info

Product

Resources

About