Uptake and speciation of selenium in garlic cultivated in soil amended with symbiotic fungi (mycorrhiza) and selenate

Abstract

The scope of the work was to investigate the influence of selenate fertilisation and the addition of symbiotic fungi (mycorrhiza) to soil on selenium and selenium species concentrations in garlic. The selenium species were extracted from garlic cultivated in experimental plots by proteolytic enzymes, which ensured liberation of selenium species contained in peptides or proteins. Separate extractions using an aqueous solution of enzyme-deactivating hydroxylamine hydrochloride counteracted the possible degradation of labile selenium species by enzymes (such as alliinase) that occur naturally in garlic. The selenium content in garlic, which was analysed by ICP-MS, showed that addition of mycorrhiza to the natural soil increased the selenium uptake by garlic tenfold to 15 microg g(-1) (dry mass). Fertilisation with selenate and addition of mycorrhiza strongly increased the selenium content in garlic to around one part per thousand. The parallel analysis of the sample extracts by cation exchange and reversed-phase HPLC with ICP-MS detection showed that gamma-glutamyl-Se-methyl-selenocysteine amounted to 2/3, whereas methylselenocysteine, selenomethionine and selenate each amounted to a few percent of the total chromatographed selenium in all garlic samples. Se-allyl-selenocysteine and Se-propyl-selenocysteine, which are selenium analogues of biologically active sulfur-containing amino acids known to occur in garlic, were searched for but not detected in any of the extracts. The amendment of soil by mycorrhiza and/or by selenate increased the content of selenium but not the distribution of detected selenium species in garlic. Finally, the use of two-dimensional HPLC (size exclusion followed by reversed-phase) allowed the structural characterisation of gamma-glutamyl-Se-methyl-selenocysteine and gamma-glutamyl-Se-methyl-selenomethionine in isolated chromatographic fractions by quadrupole time-of-flight mass spectrometry.

Extracellular thiol-assisted selenium uptake dependent on the x c − cystine transporter explains the cancer-specific cytotoxicity of selenite

“…Cells were washed with PBS and harvested with trypsin, followed by centrifugation at 300 ϫ g for 8 min, after which the medium was discarded. The resulting pellet was dissolved in 3 mL of Tris-HCl (100 mM) and sonicated for 4 ϫ 10 s. Quantification of selenium was performed with inductively coupled plasma mass spectroscopy (29).…”

Utilization of Arbuscular Mycorrhizal Fungi in Production of Allium Species

“…Действительно, установлено, что добавление Glomus intraradices в почву повышает аккумулирование селена чесно-ком в 10 раз с 1,5 до 15 мг/кг с.м. (Larsen et al, 2006).Степень обогащения растений селеном повышается также и при совместном использовании Glomus intraradices и селената Рис.7. Влияние АМГ на активность аллииназы (Borde et al,2009) Fig.7 Effect of AMF on alliinase activity (Borde et al, 2009 (Perner et al, 2006) без использования компоста.…”

“…Effect of AMF on zinc accumulation by A.porrum pseudo-stems with composting (Perner et al, 2006) [ 98 ] натрия. Установлено, что в таком продукте основную часть (2/3) производных селена составляет γ-глутамил-Se-метил-селеноцистеин (вещество с наиболее выраженными антикан-церогенными свойствами), в то же время существенно мень-шее количество присутствует в виде метил селеноцистеина, селенометионина и селената (Larsen et al, 2006). С другой стороны, Рatharajan & Raaman (2012) отмечают, что совмест-ная инокуляция чеснока с G. fasciculatum и внесение двуоки-си селена в почву приводит к подавлению спорообразования АМГ.…”

Speciation of selenium dietary supplements; formation of S-(methylseleno)cysteine and other selenium compounds

“…This study excited considerable public and scientific interest in the nutritional and clinical importance of selenium, notably in respect to potential cancer mitigation, and it has stimulated a number of further trials to better evaluate its efficacy. Principal amongst these has been the Selenium and Vitamin E Cancer Prevention Trial (SELECT) in the US, Puerto Rico and Canada [43][44][45][46], and the Prevention of Cancer by Intervention with Selenium (PRE-CISE) trial in the UK, Denmark and Sweden [47][48][49]. There is now considerable debate regarding both the planning and the results of these studies.…”