Metabolic Response of the Yeast Candida utilis During Enrichment in Selenium

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.

Screening of Selenium/Glutathione-Enriched Candida utilis and Its Anti-inflammatory and Antioxidant Activities in Mice

This study aimed to screen a mutant of Candida utilis SE-172 with high selenite tolerance and glutathione (GSH) biosynthesis capability via 60Co γ-radiation mutagenesis to prepare selenium (Se)-enriched yeast. The maximal intracellular contents of GSH and organic Se of 22.94 mg/g and 1308.1 μg/g were obtained, respectively, under a batch culture of SE-172. The physiological mechanism underlying increased GSH and organic Se contents in Se/GSH-enriched C. utilis SE-172 was revealed based on assaying activities of γ-glutamylcysteine synthase (γ-GCS) involved in GSH biosynthesis and selenophosphate synthase (SPS) related to organic Se bioconversion, and by determining intracellular ATP and NADH contents and ATP/ADP and NADH/NAD+ ratios associated with energy supply and regeneration. Moreover, the effect of this selenized yeast on anti-inflammatory and antioxidant activities in mice with colitis was investigated. The supplementation of Se/GSH-enriched yeast decreased the dextran sodium sulfate-induced damage to colon tissues, reduced the expression of pro-inflammatory factors [interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α)] in serum, increased the antioxidant-related enzyme [superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px)] activities, and decreased the malondialdehyde content in colon. The Se/GSH-enriched C. utilis SE-172 showed potent anti-inflammatory and antioxidant activities in mice with colitis.

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.

De novo assembly and characterization of the transcriptome of Morchella esculenta growth with selenium supplementation

Although Morchella esculenta (L.) Pers. is an edible and nutritious mushroom with significant selenium (Se)-enriched potential, its biological response to selenium stimuli remains unclear. This study explored the effect of selenium on mushroom growth and the global gene expression profiles of M. esculenta. While 5 µg mL-1selenite treatment slightly promoted mycelia growth and mushroom yield, 10 µg mL-1significantly inhibited growth. Based on comparative transcriptome analysis, samples treated with 5 µg mL-1 and 10 µg mL-1 of Se contained 16,061 (452 upregulated and 15,609 downregulated) and 14,155 differentially expressed genes (DEGs; 800 upregulated and 13,355 downregulated), respectively. Moreover, DEGs were mainly enriched in the cell cycle, meiosis, aminoacyl-tRNA biosynthesis, spliceosome, protein processing in endoplasmic reticulum pathway, and mRNA surveillance pathway in both selenium-treated groups. Among these, MFS substrate transporter and aspartate aminotransferase genes potentially involved in Se metabolism and those linked to redox homeostasis were significantly upregulated, while genes involved in isoflavone biosynthesis and flavonoid metabolism were significantly downregulated. Gene expression levels increased alongside selenite treatment concentration, suggesting that high Se concentrations promoted M. esculenta detoxification. These results can be used to thoroughly explain the potential detoxification and Se enrichment processes in M. esculenta and edible fungi.

Multi-pathways-mediated mechanisms of selenite reduction and elemental selenium nanoparticles biogenesis in the yeast-like fungus Aureobasidium melanogenum I15

Selenium (Se) plays a critical role in diverse biological processes and is widely used across manufacturing industries. However, the contamination of Se oxyanions also poses a major public health concern. Microbial transformation is a promising approach to detoxify Se oxyanions and produce elemental selenium nanoparticles (SeNPs) with versatile industrial potential. Yeast-like fungi are an important group of environmental microorganisms, but their mechanisms for Se oxyanions reduction remain unknown. In this study, we found that Aureobasidium melanogenum I15 can reduce 1.0 mM selenite by over 90% within 48 h and efficiently form intracellular or extracellular spherical SeNPs. Metabolomic and proteomic analyses disclosed that A. melanogenum I15 evolves a complicated selenite reduction mechanism involving multiple metabolic pathways, including the glutathione/glutathione reductase pathway, the thioredoxin/thioredoxin reductase pathway, the siderophore-mediated pathway, and multiple oxidoreductase-mediated pathways. This study provides the first report on the mechanism of selenite reduction and SeNPs biogenesis in yeast-like fungi and paves an alternative avenue for the bioremediation of selenite contamination and the production of functional organic selenium compounds.

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.

Advances in the Study of Selenium-Enriched Probiotics: From the Inorganic Se into Se Nanoparticles

Selenium (Se) is a momentous metallic element that plays an irreplaceable role in biochemical activities. Se deficiency remains a nutritional challenge across the world. Organic Se supplementation is the most effective treatment means for Se deficiency. Organic Se transformed from Se-enriched probiotics show outstanding excellent properties in antibacteria, anti-oxidation, anti-inflammation, and immunoregulation. Studying the influencing factors for Se enrichment capacity and enrichment mechanisms of Se-enriched probiotics is conducive to the exploit of more potent Se-enriched probiotics. Se-enriched probiotics transform inorganic Se into Se nanoparticles (SeNPs), which have been widely used in animal husbandry and biomedical field. In this paper, the novel development of Se-enriched probiotics is reviewed, and the bioactivities of SeNPs are assessed, so as to display their potential application prospects. The excellent role of SeNPs in anti-oxidation is summarized, and the mechanism by which SeNPs improve Se deficiency and boost animal health is explained.

Detoxification of Selenium Yeast on Mycotoxins and Heavy Metals: a Review

Mycotoxins are secondary metabolites produced by specific fungi. More than 400 different mycotoxins are known in the world, and the concentration of these toxins in food and feed often exceeds the acceptable limit, thus causing serious harm to animals and human body. At the same time, modern industrial agriculture will also bring a lot of environmental pollution in the development process, including the increase of heavy metal content, and often the clinical symptoms of low/medium level chronic heavy metal poisoning are not obvious, thus delaying the best treatment opportunity. However, the traditional ways of detoxification cannot completely eliminate the adverse effects of these toxins on the body, and sometimes bring some side effects, so it is essential to find a new type of safe antidote. Trace element selenium is among the essential mineral nutrient elements of human and animal bodies, which can effectively remove excessive free radicals and reactive oxygen species in the body, and has the effects of antioxidant, resisting stress, and improving body immunity. Selenium is common in nature in inorganic selenium and organic selenium. In previous studies, it was found that the use of inorganic selenium (sodium selenite) can play a certain protective role against mycotoxins and heavy metal poisoning. However, while it plays the role of antioxidant, it will also have adverse effects on the body. Therefore, it was found in the latest study that selenium yeast could not only replace the protective effect of sodium selenite on mycotoxins and heavy metal poisoning, but also improve the immunity of the body. Selenium yeast is an organic selenium source with high activity and low toxicity, which is produced by selenium relying on the cell protein structure of growing yeast. It not only has high absorption rate, but also can be stored in the body after meeting the physiological needs of the body for selenium, so as to avoid selenium deficiency again in the short term. However, few of these studies can clearly reveal the protective mechanism of yeast selenium. In this paper, the detoxification mechanism of selenium yeast on mycotoxins and heavy metal poisoning was reviewed, which provided some theoretical support for further understanding of the biological function of selenium yeast and its replacement for inorganic selenium. The conclusions suggest that selenium yeast can effectively alleviate the oxidative damage by regulating different signaling pathways, improving the activity of antioxidant enzymes, reversing the content of inflammatory factors, regulating the protein expression of apoptosis-related genes, and reducing the accumulation of mycotoxins and heavy metals in the body.

Selenium in the Prevention of SARS-CoV-2 and Other Viruses

The rapid spread of new pathogens (SARS-CoV-2 virus) that negatively affect the human body has huge consequences for the global public health system and the development of the global economy. Appropriate implementation of new safety regulations will improve the functioning of the current model supervising the inhibition of the spread of COVID-19 disease. Compliance with all these standards will have a key impact on the health behavior of individual social groups. There have been demonstrably effective treatments that proved to be effective but were rapidly dismissed for unknown reasons, such as ivermectin and hydroxychloroquine. Various measures are used in the world to help inhibit its development. The properties of this element provide hope in preventing the development of the SARS-CoV-2 virus. The aim of this review is to synthesize the latest literature data and to present the effect of sodium selenite in reducing the incidence of COVID-19 disease.

Nano selenium-enriched probiotic Lactobacillus enhances alum adjuvanticity and promotes antigen-specific systemic and mucosal immunity

Nano selenium-enriched probiotics have been identified to improve immune responses, such as alleviating inflammation, antioxidant function, treatment of tumors, anticancer activity, and regulating intestinal flora. However, so far, there is little information on improving the immune effect of the vaccine. Here, we prepared nano selenium-enriched Levilactobacillus brevis 23017 (SeL) and heat-inactivated nano selenium-enriched L. brevis 23017 (HiSeL) and evaluated their immune enhancing functions on the alum-adjuvanted, inactivated Clostridium perfringens type A vaccine in mouse and rabbit models, respectively. We found that SeL enhanced immune responses of the vaccine by inducing a more rapid antibody production, eliciting higher immunoglobulin G (IgG) antibody titers, improving secretory immunoglobulin A (SIgA) antibody level and cellular immune response, and regulating Th1/Th2 immune response, thus helping to induce better protective efficacy after challenge. Moreover, we confirmed that the immunoenhancement effects are related to regulating oxidative stress, cytokine secretion, and selenoprotein expression. Meanwhile, similar effects were observed in HiSeL. In addition, they show enhanced humoral immune response at 1/2 and 1/4 standard vaccine doses, which confirms their prominent immune enhancement effect. Finally, the effect of improving vaccine immune responses was further confirmed in rabbits, which shows that SeL stimulates the production of IgG antibodies, generates α toxin-neutralizing antibodies rapidly, and reduces the pathological damage to intestine tissue. Our study demonstrates that nano selenium-enriched probiotics improve the immune effect of the alum adjuvants vaccine and highlight its potential usage in remedying the disadvantages of alum adjuvants.

Isotopologue pattern based data mining for selenium species from HILIC-ESI-Orbitrap-MS-derived spectra

Automated and specific picking of selenium-containing molecular entities has not been an obvious option for software tools associated with electrospray high-resolution mass spectrometry (MS). In our study, a comprehensive pattern matching approach based on intra-isotopologue distance and isotopologue ratio data was critically evaluated in terms of reproducibility and selenium isotope selection on three samples, including selenized Torula yeast and the selenium hyperaccumulator plant Cardamine violifolia. Hydrophilic interaction liquid chromatography was applied to provide a one-step separation for water soluble metabolites to put an end to the need for either orthogonal setups or poor retention on reversed phase chromatography. Assistance from inductively coupled plasma-MS was taken only for chromatographic verification purposes, and the involvement of absolute mass defect (MD) data in selenometabolite-specific screening was assessed by multivariate statistical tools. High focus was placed on screening efficiency and on the validation of discovered selenized molecules to avoid reporting of artefacts. From the >1000 molecular entries detected, selenium-containing molecules were picked up with a recovery rate of >88% and a false positive rate of <10%. Isotop(ologu)e pairs of 78Se-80Se and 80Se-82Se proved to be the most performant in the detection. On the basis of accurate mass information and hypothetical deamination processes, elemental composition could be proposed for 72 species out of the 75 selenium species encountered without taking into account selenocompound databases. Absolute MD data were used to significantly differentiate a potentially sample-specific subgroup of false positive molecular entities from non-selenized and selenized entities.

Yeast Probiotic and Yeast Products in Enhancing Livestock Feeds Utilization and Performance: An Overview

The intensive use of antibiotics as growth-promoting agents in animal production has resulted in the spread of animal antibiotic resistance and possibly human antibiotic resistance. Based on this premise, it is significant to explore an alternative approach to preventing infectious diseases and promoting animal growth and health. Yeast as the main natural growth promoter in livestock nutrition has been extensively studied for decades. Numerous yeasts and yeast-containing products are produced, marketed, and used in animal feed as providers of nutrient sources, probiotics, and nutrients or serve distinct nutritional functions. A large amount of scientific research suggests that yeasts and their derivatives may be good for animal growth performance and health, especially when animals are housed in poor sanitation or are suffering from disease. However, when yeasts are used as a surrogate for livestock antibiotics, the results vary according to several factors, including yeast species, yeast product components, feed ingredients, animal category, type of symptoms, and differences in the rearing environment. In this review, the effects of different yeasts on different animals will be reviewed. The types of widely used yeast products, their functional characteristics, and application effects will be discussed in order to provide a reference for the development and application of yeast feed products.

Effects of Compound Mycotoxin Detoxifier on Alleviating Aflatoxin B1-Induced Inflammatory Responses in Intestine, Liver and Kidney of Broilers

In order to alleviate the toxic effects of aflatoxins B1 (AFB1) on inflammatory responses in the intestine, liver, and kidney of broilers, the aflatoxin B1-degrading enzyme, montmorillonite, and compound probiotics were selected and combined to make a triple-action compound mycotoxin detoxifier (CMD). The feeding experiment was divided into two stages. In the early feeding stage (1−21 day), a total of 200 one-day-old Ross broilers were randomly divided into four groups; in the later feeding stage (22−42 day), 160 broilers aged at 22 days were assigned to four groups: Group A: basal diet (4.31 μg/kg AFB1); Group B: basal diet with 40 μg/kg AFB1; Group C: Group A plus 1.5 g/kg CMD; Group D: Group B plus 1.5 g/kg CMD. After the feeding experiment, the intestine, liver, and kidney tissues of the broilers were selected to investigate the molecular mechanism for CMD to alleviate the tissue damages. Analyses of mRNA abundances and western blotting (WB) of inflammatory factors, as well as immunohistochemical (IHC) staining of intestine, liver, and kidney tissues showed that AFB1 aggravated the inflammatory responses through NF-κB and TN-α signaling pathways via TLR pattern receptors, while the addition of CMD significantly inhibited the inflammatory responses. Phylogenetic investigation showed that AFB1 significantly increased interleukin-1 receptor-associated kinase (IRAK-1) and mitogen-activated protein kinase (MAPK) activities (p < 0.05), which were restored to normal levels by CMD addition, indicating that CMD could alleviate cell inflammatory damages induced by AFB1.

The Barrier-Enhancing Function of Soluble Yam (Dioscorea opposita Thunb.) Polysaccharides in Rat Intestinal Epithelial Cells, as Affected by the Covalent Se Conjugation

The non-starch yam polysaccharides (YP) are the bioactive substances of edible yam, while Se is an essential nutrient for the human body. Whether a covalent conjugation of Se to YP might cause bioactivity change for the resultant selenylated YP in the intestine is still insufficiently studied, including the critical intestinal barrier function. In this study, two selenylated YP products, namely, YPSe-I and YPSe-II, with corresponding Se contents of 795 and 1480 mg/kg, were obtained by the reaction of YP and Na2SeO3 in the presence of HNO3 and then assessed for their bioactivities to a cell model (i.e., rat intestinal epithelial IEC-6 cells). The results showed that YP, YPSe-I, and YPSe-II at 5–80 μg/mL dosages could promote cell growth with treatment times of 12–24 h. The three samples also could improve barrier integrity via increasing cell monolayer resistance and anti-bacterial activity against E. coli or by reducing paracellular permeability and bacterial translocation. Additionally, the three samples enhanced F-actin distribution and promoted the expression of the three tight junction proteins, namely, zonula occluden-1, occludin, and claudin-1. Meanwhile, the expression levels of ROCK and RhoA, two critical proteins in the ROCK/RhoA singling pathway, were down-regulated by these samples. Collectively, YPSe-I and, especially, YPSe-II were more potent than YP in enhancing the assessed bioactivities. It is thus concluded that this chemical selenylation of YP brought about enhanced activity in the cells to promote barrier integrity, while a higher selenylation extent of the selenylated YP induced much activity enhancement. Collectively, the results highlighted the important role of the non-metal nutrient Se in the modified polysaccharides.

Effect of selenium and methods of protein extraction on the proteomic profile of Saccharomyces yeast

Selenium may influence the biosynthesis of individual proteins in the yeast cell cytosol. In this study, we used two-dimensional (2D) electrophoresis to identify proteins that are differentially expressed by the enrichment of selenium in Saccharomyces cerevisiae yeast cells. We chose eight protein fractions for further proteomic analysis. A detailed analysis was performed using the Ultraflextreme matrix-assisted laser desorption/ionisation time-of-flight/time-of-flight mass spectrometer, which enables fast and accurate measurement of the molecular weight of the analysed proteins. This study, for the first time, provides evidence that selenium-enriched yeast contains higher levels of mitochondria malate dehydrogenase, adenosine-5'-triphosphate (ATP)-dependent RNA helicase dbp3, and tryptophan dimethylallyltransferase, and alanyl-tRNA editing protein AlaX than yeast without the addition of selenium. It should be emphasised that the proteomic variability obtained reflects the high biological and complexity of yeast metabolism under control and selenium-enriched conditions and can be properly used in the future as a model for further research aimed at determining the expression of appropriate metabolic genes.

A novel yeast strain Geotrichum sp. CS-67 capable of accumulating heavy metal ions

Bioremediation, which has several advantages over traditional methods, represents an alternative means of dealing with heavy metal pollution. We screened for microorganisms showing heavy metal tolerance in polluted mangrove soils. A novel yeast, Geotrichum sp. CS-67, was discovered and tested for tolerance of Cu²⁺, Zn²⁺, and Ni²⁺. Zn²⁺ was the most efficiently sequestered by Geotrichum sp. CS-67 followed by Ni²⁺ and Cu²⁺. Zn²⁺ and Ni²⁺ were actively taken up into the cell, while Cu²⁺ was adsorbed to the cell wall. We used RNA-Seq to show that a large number of genes involved in the physiological and biochemical processing of heavy metals were differentially expressed in this yeast when it was subjected to Zn²⁺ and Ni²⁺ stress. From this panel, we selected the SED1, GDI1 and ZRT1 genes for validation by qRT-PCR and discovered that, during Zn²⁺ and Ni²⁺ stress, SED1 and GDI1 were upregulated, while ZRT1 was downregulated, which was consistent with the RNA-Seq results and the biochemical function of these genes. In conclusion, the novel yeast Geotrichum sp. CS-67 has a marked ability to accumulate heavy metal ions, making it of great interest as a possible microbial agent for heavy metal pollution remediation in the future.

Influence of Selenium Biofortification of Soybeans on Speciation and Transformation during Seed Germination and Sprouts Quality

Selenium (Se) biofortification during seed germination is important not only to meet nutritional demands but also to prevent Se-deficiency-related diseases by producing Se-enriched foods. In this study, we evaluated effects of Se biofortification of soybeans on the Se concentration, speciation, and species transformation as well as nutrients and bioactive compounds in sprouts during germination. Soybean (Glycine max L.) seedlings were cultivated in the dark in an incubator with controlled temperature and water conditions and harvested at different time points after soaking in Se solutions (0, 5, 10, 20, 40, and 60 mg/L). Five Se species and main nutrients in the sprouts were determined. The total Se content increased by 87.3 times, and a large portion of inorganic Se was transformed into organic Se during 24 h of germination, with 89.3% of the total Se was bound to soybean protein. Methylselenocysteine (MeSeCys) and selenomethionine (SeMet) were the dominant Se species, MeSeCys decreased during the germination, but SeMet had opposite trend. Se biofortification increased contents of total polyphenol and isoflavonoid compounds and amino acids (both total and essential), especially in low-concentration Se treatment. In conclusion, Se-enriched soybean sprouts have promising potential for Se supplementation and as functional foods.

Lipids and Trehalose Actively Cooperate in Heat Stress Management of Schizosaccharomyces pombe

Homeostatic maintenance of the physicochemical properties of cellular membranes is essential for life. In yeast, trehalose accumulation and lipid remodeling enable rapid adaptation to perturbations, but their crosstalk was not investigated. Here we report about the first in-depth, mass spectrometry-based lipidomic analysis on heat-stressed Schizosaccharomyces pombe mutants which are unable to synthesize (tps1Δ) or degrade (ntp1Δ) trehalose. Our experiments provide data about the role of trehalose as a membrane protectant in heat stress. We show that under conditions of trehalose deficiency, heat stress induced a comprehensive, distinctively high-degree lipidome reshaping in which structural, signaling and storage lipids acted in concert. In the absence of trehalose, membrane lipid remodeling was more pronounced and increased with increasing stress dose. It could be characterized by decreasing unsaturation and increasing acyl chain length, and required de novo synthesis of stearic acid (18:0) and very long-chain fatty acids to serve membrane rigidification. In addition, we detected enhanced and sustained signaling lipid generation to ensure transient cell cycle arrest as well as more intense triglyceride synthesis to accommodate membrane lipid-derived oleic acid (18:1) and newly synthesized but unused fatty acids. We also demonstrate that these changes were able to partially substitute for the missing role of trehalose and conferred measurable stress tolerance to fission yeast cells.

Effects of Dietary Yucca Schidigera Extract and Oral Candida utilis on Growth Performance and Intestinal Health of Weaned Piglets

Weaning piglets experienced the transformation from breast milk to solid feed and present the proliferation of pathogens, the presence of diarrhea, poor growth performance and even death. Plant extracts and probiotics have certain potential in improving animal growth performance, antioxidant capacity and immune function. The purpose of this study was to explore the effects of dietary yucca schidigera extract (YSE) and oral Candida utilis (CU) on growth performance and intestinal health weaned piglets. According to a 2 × 2 factorial design with the main factors being CU (orally administered 1 mL of 0.85% saline with or without CU; fed basal diet with or without 120 mg/kg YSE), forty 28 d healthy weaned piglets were randomly allocated into four groups of 10 barrows each: (1) piglets fed basal diet and orally administered 1 mL of 0.85% saline (CON); (2) piglets fed basal diet and orally administered 1 mL 1 × 10⁹ cfu/mL C. utilis in 0.85% saline (CU); (3) piglets fed the basal diet containing YSE (120 mg/kg) and orally administered 1 mL of 0.85% saline (YSE); (4) Piglets fed the basal diet containing 120 mg/kg YSE and 1 mL 1 × 10⁹ cfu/mL C. utilis in 0.85% saline (YSE+CU). This study lasted 28 days and evaluated the effects of dietary YSE and oral CU on growth performance, immunity, antioxidant function, ileal morphology, and intestinal microflora in weaned piglets. Dietary YSE increased ADG, the spleen and lymph node indexes, serum GLU, BUN, T-SOD, T-AOC, CAT concentrations, ileal villus height and villus height/crypt depth, jejunal occludin, and β-definsin-2 concentrations and ileal occludin concentration in weaned piglets (P < 0.05); decreased the diarrhea rate and mortality, rectal pH and urine pH, the BUN and MDA concentrations, crypt depth (P < 0.05); improved the diversity of cecal microflora. Orally CU increased ADG, and ADFI, the T-SOD, T-AOC, and CAT activity, ileal villus height, villus height/crypt depth, jejunum occludin, and β-definsin-2 concentrations (P < 0.05); reduced the diarrhea rate and mortality, urine pH, the BUN and MDA concentrations, crypt depth (P < 0.05); improved the diversity of cecal microflora. Dietary YSE and orally CU increased the T-SOD, T-AOC, and CAT activity, villus height/crypt depth, jejunal occludin concentration; reduced the diarrhea rate of weaned piglets by 28%, gastric pH, ileal pH, cecal pH and urine pH, MDA, crypt depth; improved the diversity of cecal microflora. YSE and CU could improve the growth performance, reduce the diarrhea rate, improve intestinal health, and increase the diversity and abundance of cecal microflora in weaned piglets and expected to be used as antibiotics alternative feed additives in the production of weaned piglets.

A New Approach for the Production of Selenium-Enriched and Probiotic Yeast Biomass from Agro-Industrial by-Products in a Stirred-Tank Bioreactor

The production of biomolecules using agro-industrial by-products as feedstock is a growing trend worldwide. Selenium (Se) is a trace element essential for health, and the Se-enrichment of yeast biomass can enhance its benefits. This study investigated the feasibility of the production of Saccharomyces cerevisiae Se-enriched biomass using a medium composed of corn bran and soybean bran acid hydrolysates as carbon and nitrogen sources in a stirred-tank reactor. After hydrolysis, hydrolysates presented complex composition and high concentrations of sugars, proteins, and minerals. The use of a stirred-tank bioreactor leads to the production of 9 g/L S. cerevisiae biomass enriched with 236.93 μg/g Se, and 99% cell viability. Likewise, the combination of sugarcane molasses and soybean bran hydrolysate was effective for cell growth of a probiotic strain of S. cerevisiae with a 24.08% β-glucan content. The results demonstrated that starchy acid hydrolysates are low-cost and efficient substrates for the production of yeast biomass and derivate products and may contribute to further studies for a sustainable development of biorefinery technologies.

Selenium accumulation, speciation, and its effect on nutritive value of Flammulina velutipes (Golden needle mushroom)

Flammulina velutipes is one of the most popular edible mushrooms worldwide. A selenium-biofortification method for its fruiting body was developed using selenite. This study investigated the selenium content, distribution, speciation and the effect of selenium on mushroom growth, nutritive value, and mineral accumulation. Results showed that F. velutipes accumulated nearly 108 μg/g of organic selenium under treatment with 20 μg/g selenite, which accounts for over 97% of total selenium. Most (60-74%) of selenium combined with the protein fraction, whereas 15-21% combined with the polysaccharide fraction. Selenomethionine (56.8%), selenocysteine (22.8%), and methylselenocysteine (17.3%) were the main organic selenium compounds in the fruiting body. Selenium biofortification increased the biomass yield of fruiting body and elevated the content of polysaccharides, proteins, total amino acids, essential amino acids, and several minerals, including iron, calcium, and copper. F. velutipes might become a suitable selenium supplement.