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*

In this paper, 29 endophytes were isolated from different organs and tissues of Lycium barbarum of Ningxia by tablet coating method, 18 of them was fungi, and 11 of them was actinomycetes. The endophytes quantity in the different tissues were leaves > flowers > roots >fruits; The hydroxyl radical scavenging activities of 11 endophytes were investigated by Fenton reaction, and total antioxidant capacities of them were examined by a. total antioxidant capacity test kit; culture features and strain-specific sequence analysis were employed to explore the diversity of the 11 endophytes. The result showed that 5 fungi and 6 actinomycetes that having antioxidant activity could be phylogenetically classified into 3 genera, 3 genera and 3 families, respectively. The total antioxidant capacity and hydroxyl radical scavenging activity of the 11 endophytes showed distinct difference. The antioxidant activity of Aspergillus were stronger, among which total antioxidant capacity of fL1 was (188.5 ± 0.549) U · mL⁻¹ and the IC₅₀ was 0.3 mg · L⁻¹; the IC₅₀ of strain fL1 was 0.42 mg · L⁻¹ and the total antioxidant capacity of fL9 was (113.63 ± 1.021) U · mL⁻¹, all of them were stronger than the positive control Vit C. The experimental results indicated that endophytic fungi of L. barbarum of Ningxia have a great developing and application prospect for the development of antioxidant agent.
Antioxidants ; chemistry ; Bacteria ; chemistry ; classification ; genetics ; isolation & purification ; Biodiversity ; Endophytes ; classification ; genetics ; isolation & purification ; Fungi ; chemistry ; classification ; genetics ; isolation & purification ; Lycium ; microbiology ; Molecular Sequence Data ; Oxidation-Reduction

To investigate the production status and the safety influence factors of wolfberry in China. We investigated the detailed factors which affect the quality safe of wolfberry in the periods of July-August 2013 and July-September 2009. The factors include fertilizing patterns, the used pesticide and preliminary process wolfberry. The factors were discussed according to the results of investigation, and suggestions were proposed for the management and production departments of wolfberry.
China ; Fertilizers ; analysis ; Lycium ; chemistry ; growth & development ; microbiology ; parasitology ; Pest Control ; Plant Diseases ; microbiology ; parasitology ; prevention & control