The importance of selenium in food enrichment processes. A comprehensive review

The Promising Role of Selenium and Yeast in the Fight Against Protein Amyloidosis

In recent years, increasing attention has been paid to research on diseases related to the deposition of misfolded proteins (amyloids) in various organs. Moreover, modern scientists emphasise the importance of selenium as a bioelement necessary for the proper functioning of living organisms. The inorganic form of selenium-sodium selenite (redox-active)-can prevent the formation of an insoluble polymer in proteins. It is very important to undertake tasks aimed at understanding the mechanisms of action of this element in inhibiting the formation of various types of amyloid. Furthermore, yeast cells play an important role in this matter as a eukaryotic model organism, which is intensively used in molecular research on protein amyloidosis. Due to the lack of appropriate treatment in the general population, the problem of amyloidosis remains unsolved. This extracellular accumulation of amyloid is one of the main factors responsible for the occurrence of Alzheimer's disease. The review presented here contains scientific information discussing a brief description of the possibility of amyloid formation in cells and the use of selenium as a factor preventing the formation of these protein aggregates. Recent studies have shown that the yeast model can be successfully used as a eukaryotic organism in biotechnological research aimed at understanding the essence of the entire amyloidosis process. Understanding the mechanisms that regulate the reaction of yeast to selenium and the phenomenon of amyloidosis is important in the aetiology and pathogenesis of various disease states. Therefore, it is imperative to conduct further research and analysis aimed at explaining and confirming the role of selenium in the processes of protein misfolding disorders. The rest of the article discusses the characteristics of food protein amyloidosis and their use in the food industry. During such tests, their toxicity is checked because not all food proteins can produce amyloid that is toxic to cells. It should also be noted that a moderate diet is beneficial for the corresponding disease relief caused by amyloidosis.

Study of selenium enrichment metabolomics in Bacillus subtilis BSN313 via transcriptome analysis

In this study, the transcriptome analysis was practiced to identify potential genes of probiotic Bacillus subtilis BSN313 involved in selenium (Se) enrichment metabolism. The transcriptomic variation of the strain was deliberated in presence of three different sodium selenite concentrations (0, 3, and 20 μg/mL). The samples were taken at 1 and 13 h subsequent to inoculation of selenite and gene expression profiles in Se metabolism were analyzed through RNA sequencing. The gene expression levels of the pre log phase were lower than the stationary phase. It is because, the bacteria has maximum grown with high concentration of Se (enriched with organic Se), at stationary phase. Bacterial culture containing 3 μg/mL concentration of inorganic Se (sodium selenite) has shown highest gene expression as compared to no or high concentration of Se. This concentration (3 μg/mL) of sodium selenite (as Se) in the medium promoted the upregulation of thioredoxin reductase expression, whereas its higher Se concentration inhibited the formation of selenomethionine (SeMet). The result of 5 L bioreactor fermentation showed that SeMet was also detected in the fermentation supernatant as the growth entered in the late stationary phase and reached up to 857.3 ng/mL. The overall intracellular SeMet enriched content in BSN313 was extended up to 23.4 μg/g dry cell weight. The other two selenoamino acids (Se-AAs), methyl-selenocysteine, and selenocysteine were hardly detected in medium supernatant. From this study, it was concluded that SeMet was the highest content of organic Se byproduct biosynthesized by B. subtilis BSN313 strain in Se-enriched medium during stationary phase. Thus, B. subtilis BSN313 can be considered a commercial probiotic strain that can be used in the food and pharmaceutical industries. This is because it can meet the commercial demand for Se-AAs (SeMet) in both industries.

Exposure to Selenomethionine and Selenocystine Induces Redox-Mediated ER Stress in Normal Breast Epithelial MCF-10A Cells

Selenium is an essential trace element co-translationally incorporated into selenoproteins with important biological functions. Health benefits have long been associated with selenium supplementation. However, cytotoxicity is observed upon excessive selenium intake. The aim of this study is to investigate the metabolic pathways underlying the response to the selenium-containing amino acids selenomethionine and selenocysteine in a normal human breast epithelial cell model. We show that both selenomethionine and selenocystine inhibit the proliferation of non-cancerous MCF-10A cells in the same concentration range as cancerous MCF-7 and Hela cells, which results in apoptotic cell death. Selenocystine exposure in MCF-10A cells caused a severe depletion of free low molecular weight thiols, which might explain the observed upregulation of the expression of the oxidative stress pathway transcription factor NRF2. Both selenomethionine and selenocystine induced the expression of target genes of the unfolded protein response (GRP78, ATF4, CHOP). Using a redox-sensitive fluorescent probe targeted to the endoplasmic reticulum (ER), we show that both selenoamino acids shifted the ER redox balance towards an even more oxidizing environment. These results suggest that alteration of the redox state of the ER may disrupt protein folding and cause ER stress-induced apoptosis in MCF-10A cells exposed to selenoamino acids.

In vitro digestion and characterization of selenized Saccharomyces cerevisiae, Pichia fermentans and probiotic Saccharomyces boulardii

BACKGROUND AND OBJECTIVE

Yeasts have the remarkable capability to transform and integrate inorganic selenium into their cellular structures, thereby enhancing its bioavailability and reducing its toxicity. In recent years, yeasts have attracted attention as potential alternative sources of protein.

METHODS

This study explores the selenium accumulation potential of two less explored yeast strains, namely the probiotic Saccharomyces boulardii CCDM 2020 and Pichia fermentas CCDM 2012, in comparison to the extensively studied Saccharomyces cerevisiae CCDM 272. Our investigation encompassed diverse stress conditions. Subsequently, the selenized yeasts were subjected to an INFOGEST gastrointestinal model. The adherence and hydrophobicity were determined with undigested cells RESULTS: Stress conditions had an important role in influencing the quantity and size of selenium nanoparticles (SeNPs) generated by the tested yeasts. Remarkably, SeMet synthesis was limited to Pichia fermentas CCDM 2012 and S. boulardii CCDM 2020, with S. cerevisiae CCDM 272 not displaying SeMet production at all. Throughout the simulated gastrointestinal digestion, the most substantial release of SeCys2, SeMet, and SeNPs from the selenized yeasts occurred during the intestinal phase. Notably, exception was found in strain CCDM 272, where the majority of particles were released during the oral phase.

CONCLUSION

The utilization of both traditional and non-traditional selenized yeast types, harnessed for their noted functional attributes, holds potential for expanding the range of products available while enhancing their nutritional value and health benefits.

Certification of New Selenium-Enriched Yeast and Supplement Reference Materials for Selenomethionine Using Two Independent Measurement Strategies

Selenium-enriched yeast possesses the unique ability of transforming chemical selenium, such as sodium selenite, into a biologically active form, which mitigates its toxic effects on the human body. The transformation product of this process, selenomethionine, can be safely and effectively absorbed and utilized by the human body; hence, it has been spiked into a selenium-enriched supplement. This study employs two distinct measurement strategies to determine the selenomethionine content in two candidate reference materials, a selenium-enriched yeast powder and supplement, using both organic and inorganic mass spectrometry. The concentrations of selenomethionine in the selenium-enriched yeast were determined using HPLC-ICP-MS and HPLC- ESI-MS/MS, with mass fractions measured at 718 mg SeMet kg-1 and 715 mg SeMet kg-1, respectively. Notably, both methods yielded consistent results for the selenium supplement, with a selenomethionine mass fraction of 59 mg SeMet kg-1. Ultimately, the certified values of these candidate reference materials were determined as 716 mg kg-1 and 59 mg SeMet kg-1 with expanded uncertainties of 36 mg SeMet kg-1 (k = 2) and 5 mg SeMet kg-1 (k = 2), respectively. The development of these candidate reference materials serves as a valuable reference for diverse methods aiming to determine the value of organic selenium speciation in complex food substrates.

Treadmill exercise with nanoselenium supplementation affects the expression of Irisin/FNDC5 and semaphorin 3A in rats exposed to cigarette smoke extract

In the current study, we investigated the impacts of 6 weeks of aerobic interval training (AIT) with selenium nanoparticles (SeNPs) on muscle, serum, and lung irisin (FNDC5) and Sema3A in rats exposed to cigarette smoke extract (CSE). To this end, 49 male Wistar rats (8 weeks old) were divided into seven groups: control, SeNPs (2.5 mg/kg b.w by oral gavage, 3 days/week, 6 weeks), AIT (49 min/day, 5 days/week for 6 weeks, interval), SeNPs + AIT, CSE (150 µL by IP injection, 1 day/week for 6 weeks), CSE + AIT, and CSE + SeNPs + AIT. The CSE group showed a significant reduction in irisin and Sema3A serum levels, as well as a decrease in FNDC5 and Sema3A gene expression in lung tissue (p < 0.05). A combined treatment (AIT with SeNPs) significantly increased the serum level and the expression of muscle and lung irisin (FNDC5) and Sema3A in CSE received groups (p < 0.05). There was a positive and significant correlation between muscle FNDC5 and lung FNDC5 in the CSE + SeNPs + AIT group (r = 0.92, p = 0.025). In addition, there was a positive and significant correlation between serum Sema3A and lung Sema3A of CSE + SeNPs + AIT group (r = 0.97, p = 0.004). Seemingly, performing aerobic exercises with the antioxidant and anti-inflammatory supplement nano-selenium in the model of lung damage (similar to COPD) can boost myokine irisin and Sema3A, especially in serum and lung tissue. These results displayed the paracrine/endocrine regulatory function of these myokines on other tissues. In other words, these interventions emphasized the creation of crosstalk between skeletal muscles and damaged lung, focusing on its recovery; however, further research is needed.