Biosynthesized selenium nanoparticles (SeNPs) have attracted much attention because of their unique physical, chemical, and biological properties. The microbial reduction of selenium salts to SeNPs has great potential, while there is a lack of elite strains. In this study, we explored the reduction of Na₂SeO₃ by Streptomyces avermitilis into SeNPs. The colonies and hyphae of the strain and the synthesized SeNPs were characterized by optical microscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). At the same time, the inhibitory activity of SeNPs on Fusarium oxysporum, the main pathogen causing root rot of Lycium barbarum, was studied. The results showed that S. avermitilis converted Na₂SeO₃ into SeNPs and tolerated 300 mmol/L Na₂SeO₃, demonstrating strong tolerance. S. avermitilis synthesized spherical SeNPs in the cytoplasm, and most of SeNPs had a diameter of about 100 nm and were released by hyphal fracture. The SeNPs synthesized by S. avermitilis were amorphous, and their surfaces were dominated by C and Se, with the existence of O, N and other elements. SeNPs had functional groups such as -OH, C=O, C-N, and C-H, which were closely related to the stability and biological activity of SeNPs. The SeNPs synthesized by S. avermitilis showcased significant inhibitory activity on F. oxysporum, and 25.0 μmol/mL SeNPs showcased the inhibition rate of 77.61% and EC₅₀ of 0.556 μmol/mL. In conclusion, S. avermitilis can tolerate high Na₂SeO₃ stress and mediate the synthesis of SeNPs. The synthesized SeNPs have good stability and strong inhibitory activity, demonstrating the potential application value in the preparation of SeNPs and the control of L. barbarum root rot.
Streptomyces/metabolism* ; Fusarium/drug effects* ; Lycium/microbiology* ; Selenium/metabolism* ; Nanoparticles/chemistry* ; Plant Diseases/microbiology* ; Metal Nanoparticles/chemistry* ; Antifungal Agents/pharmacology*

Selenium (Se) is an essential trace element for organisms. Se deficiency will cause diseases such as Keshan disease and Kashin-Beck in human being, and huge loss to animal husbandry. Currently available Se supplements have such problems as low Se content, poor bioavailability, and poor safety. Chlorella pyrenoidosa can produce bioavailable and safe organic Se under suitable conditions, which is thus a promising Se supplement. Therefore, in this study, we tried to improve the Se tolerance and accumulation of C. pyrenoidosa by directional adaptation. To be specific, we gradually increased the concentration of Na₂SeO₃ in medium to domesticate C. pyrenoidosa and optimized the adapting time and concentration gradient of Na₂SeO₃ during the adaptation. The results showed that the adapted C. pyrenoidosa was more tolerant to Se and had stronger Se enrichment ability. In 5 L fermenter, the adapted strains could tolerate 40 mg/L Na₂SeO₃ and the synthesis rate of organic Se was 175.6% higher. Then, Se addition method in the 5 L fermenter was optimized. The result demonstrated that addition of Na₂SeO₃ at 40 mg/L during heterotrophic culture achieved the final dry weight of C. pyrenoidosa cells at 106.4 g/L, content of organic Se at 1 227 mg/kg, and synthesis rate of organic Se at 1.36 mg/(L·h). Compared with the reported highest cell density of 75 g/L and the highest organic Se content of 560 mg/kg, the corresponding figures in this study were 41.9% and 119.1% higher, respectively. In conclusion, directional adaptation can remarkably improve the Se tolerance and enrichment of C. pyrenoidosa.
Animals ; Humans ; Selenium/pharmacology* ; Chlorella ; Heterotrophic Processes

In recent years, selenium nanoparticles (SeNPs) have been widely used in many fields such as nanotechnology, biomedicine and environmental remediation due to their good electrical conductivity, photothermal properties and anticancer properties. In this study, the cell-free supernatant, whole cell and the cell-free extracts of the strain Cupriavidus sp. SHE were used to synthesize SeNPs, and several methods were applied to analyze the crystal structure and surface functional groups of the nanoparticles. Finally, Pseudomonas sp. PI1 (G⁺) and Escherichia coli BL21 (G⁻) were selected to investigate the antibacterial properties of SeNPs. Cell-free supernatant, whole cell and cell-free extracts of the strain could synthesize SeNPs. As for the cell-free supernatant, selenite concentration of 5 mmol/L and pH=7 were favorable for the synthesis of SeNPs. TEM images show that the average size of nanospheres synthesized by the supernatant was 196 nm. XRD analysis indicates the hexagonal crystals structure of SeNPs. FTIR and SDS-PAGE confirmed the proteins bound to the surfaces of SeNPs. SeNPs synthesized by cell-free supernatant showed no antimicrobial activities against Pseudomonas sp. PI1 and Escherichia coli BL21 (DE3). These results suggest that proteins played an important role in biotransformation of SeNPs in an eco-friendly process, and SeNPs synthesized in this study were non-toxic and biologically compatible, which might be applied in other fields in the future.
Anti-Bacterial Agents ; pharmacology ; Bacteria ; drug effects ; Cupriavidus ; metabolism ; Nanoparticles ; Selenious Acid ; analysis ; Selenium ; chemistry ; pharmacology

OBJECTIVETo investigate chondrocyte apoptosis and the expression of biochemical markers associated with apoptosis in Kashin-Beck disease (KBD) and in an established T-2 toxin- and selenium (Se) deficiency-induced rat model.

METHODSCartilages were collected from the hand phalanges of five patients with KBD and five healthy children. Sprague-Dawley rats were administered a selenium-deficient diet for 4 weeks prior to T-2 toxin exposure. The apoptotic chondrocytes were observed by terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Caspase-3, p53, Bcl-2, and Bax proteins in the cartilages were visualized by immunohistochemistry, their protein levels were determined by Western blotting, and mRNA levels were determined by real-time reverse transcription polymerase chain reaction.

RESULTSIncreased chondrocyte apoptosis was observed in the cartilages of children with KBD. Increased apoptotic and caspase-3-stained cells were observed in the cartilages of rats fed with normal and Se-deficient diets plus T-2 toxin exposure compared to those in rats fed with normal and Se-deficient diets. Caspase-3, p53, and Bax proteins and mRNA levels were higher, whereas Bcl-2 levels were lower in rats fed with normal or Se-deficiency diets supplemented with T-2 toxin than the corresponding levels in rats fed with normal diet.

CONCLUSIONT-2 toxin under a selenium-deficient nutritional status induces chondrocyte death, which emphasizes the role of chondrocyte apoptosis in cartilage damage and progression of KBD.

Adolescent ; Animals ; Apoptosis ; drug effects ; Biomarkers ; Cartilage, Articular ; physiopathology ; Child ; Chondrocytes ; physiology ; Female ; Humans ; Kashin-Beck Disease ; etiology ; physiopathology ; Male ; Matrilin Proteins ; genetics ; metabolism ; Models, Animal ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Selenium ; deficiency ; T-2 Toxin ; pharmacology

This study determined the effects of selenium on the growth of Fusarium strains and the effects of products extracted from the fungal cultures on relevant indicators of chondrocytes injury. The results showed that selenium supplementation resulted in differential effects on the mycelial growth of the strains. Levels of the chondrocyte injury indicators, including cell viability, proteoglycan and type II collagen contents and their mRNA expressions, were all reduced to varying degrees when the chondrocytes were incubated with fermentation extracts, the inhibitory effect varied depending on selenium content supplemented to fungal culture media. The results indicated that certain chain relations existed between the content of selenium in the environment, the production of some metabolites by fungi, and the occurrence of chondrocyte damage. The extent of this relationship and the role it plays in Kaschin-Beck disease pathogenesis merit further study.
Animals ; Cell Survival ; Cells, Cultured ; Chondrocytes ; pathology ; Fermentation ; Fusarium ; drug effects ; physiology ; Rabbits ; Selenium ; pharmacology

Animals ; Codonopsis ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Myocardial Reperfusion Injury ; drug therapy ; Rats ; Selenium ; pharmacology

OBJECTIVETo explore the effect of Se-riched soybean peptide (SSP) on antioxidant function in rats of fatty liver caused by high-fat diet.

METHODSForty Wistar rats were divided into 4 groups randomly and fed with standard diet and water (NC), high-fat diet and water (HC), high-fat diet and SSP (0.1 g/d) (SeH), standard diet and SSP (0.1 g/d) (SeN) respectively. After 10 weeks, the rats were killed to investigate the pimelosis level in liver tissues by Sudan III staining and the expression of hepatic GRP78 by immunohistochemical analysis. We also analyzed the changes of liver function, blood lipid, the glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in livers and serum.

RESULTSThe pimelosis level, total cholesterol (TC), triglyceride (TG), MDA contents and the expression of GRP78 in HC group were significantly higher than those in NC, SeN, SeH groups. The activities of GSH-Px and SOD in liver and serum were markedly up-regulated in SeH (P < 0.01). There was no significant difference between NC and SeN groups.

CONCLUSIONSSP can improve liver cell injury and the antioxidant functions in rats with fatty liver effectively and decrease the expression of GRP78 in liver.

Animals ; Antioxidants ; metabolism ; Diet, High-Fat ; adverse effects ; Disease Models, Animal ; Fatty Liver ; chemically induced ; metabolism ; Heat-Shock Proteins ; metabolism ; Liver ; drug effects ; metabolism ; Male ; Rats ; Rats, Wistar ; Selenium ; pharmacology ; Soybean Proteins ; pharmacology ; Soybeans ; chemistry

Alkaloids ; pharmacology ; Animals ; Liver Neoplasms, Experimental ; enzymology ; prevention & control ; Quinolizines ; pharmacology ; Rats ; Selenium ; pharmacology ; Telomerase ; metabolism ; Yeast, Dried ; pharmacology

Animals ; Codonopsis ; chemistry ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Fatigue ; drug therapy ; Female ; Hypoxia ; drug therapy ; Male ; Mice ; Selenium ; pharmacology

OBJECTIVETo study the effects of the Rich Selenium-Banqiao-Codonopsis Pilosula (BCPA) injecta on the aged rats' immune functions and its underlying mechanism.

METHODSTotally 60 rats, composed of 2, 12 and 22 month age old (half male and half female), were served as a young group, middle-age group and aged group respectively. Each group rats were randomly divided into the control and the BCPA subgroup (n = 10). The BCPA group was injected with BCPA at 7.2 g/kg intraperitoneally every day and the control group was injected the same volume of normal saline. All rats were conventionally fed for 45 days. An immune injection was performed after 15 days of BCPA injection. On the 22nd day, late-onset immune response would be induced. The caudal vein blood was collected and the antigen specific IgG, IgG1 and IgG2a antibody was detected on the 15th, 30th and 45th day. On the 45th day, the major T cell subgroups of splenic cells were analyzed and splenic cells were proliferated.

RESULTSNo significant difference in the delayed-type hypersensivity (DTH) reaction was found between the control and the BCPA subgroups in the young and middle-aged rats while the aged BCPA subgroup had a stronger DTH reaction. There was no significant difference in the blood content of specific IgG, IgG1 and IgG2a antibody between the young and middle-age BCPA group while the aged BCPA group rats had an obvious enhancing reaction to the three antibodies mentioned above (P < 0.05). There was no obvious difference in the number of the CD3+ lymphocytes and the CD4+ T helper lymphocytes between the control and the BCPA subgroup in the young aged rats while a significant increase was spotted between the middle-aged and the aged group (P < 0.05). The splenic cells from young BCPA group rats had a strong proliferation response (P < 0.05).

CONCLUSIONBCPA can enhance DTH reaction, potentiate the production of specific IgG, IgG1 and IgG2a antibody to resist KLH, improve the reaction to antigen, increase the amount of CD4+ cell, promote the immune response and had an important role in anti-immunosenescence and antioxidant capacity improvement in the aged rats.

Aging ; Animals ; CD4-Positive T-Lymphocytes ; immunology ; Codonopsis ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Female ; Immune System ; drug effects ; Immunoglobulin G ; blood ; Male ; Rats ; Selenium ; pharmacology ; Spleen ; immunology