Superoxide Dismutase Catalyzed Size-Adjustable Selenium Nanoparticles in Saccharomyces boulardii.

Selenium nanoparticles (SeNPs) are important and safe food and feed additives that can be used for dietary supplementation. In this study, a mutagenic strain of Saccharomyces boulardii was employed to obtain biologically synthesized SeNPs (BioSeNPs) with the desired particle size by controlling the dosage and duration of sodium selenite addition, and the average particle size achieved was 55.8 nm with protease A encapsulation. Transcriptomic analysis revealed that increased expression of superoxide dismutase 1 (SOD1) in the mutant strain effectively promoted the synthesis of BioSeNPs and the formation of smaller nanoparticles. Under sodium selenite stress, the mutant strain exhibited significantly increased expression of glutathione peroxidase 2 (GPx2), which was significantly greater in the mutant strain than in the wild type, facilitating the synthesis of glutathione selenol and providing abundant substrates for the production of BioSeNPs. Furthermore, based on the experimental results and transcriptomic analysis of relevant genes such as sod1, gpx2, the thioredoxin reductase 1 gene (trr1) and the thioredoxin reductase 2 gene (trr2), a yeast model for the size-controlled synthesis of BioSeNPs was constructed. This study provides an important theoretical and practical foundation for the green synthesis of controllable-sized BioSeNPs or other metal nanoparticles with potential applications in the fields of food, feed, and biomedicine.

[Study on chemical components of the essential oil from Fructus Canarii by GC-MS].

OBJECTIVE: To study on the main chemical components of essential oil from Fructus Canarii. METHODS: The essential oil from Fructus Canarii was extracted by steam-stilling and analyzed by GC-MS. The relative content of each component was determined by normalization method. RESULTS: 121 compounds were separated and 65 compounds were identified, which weighed 91.25% of the total oil. The main chemical components of the oil were caryophilene (24.78%), (+/-)-2-methylene-6,6-dimethyl,-bicyclo [3.1.1]-heptane (13.51%), p-menth-1-en-8-ol (7.15%) and so on. CONCLUSION: This experiment has provided scientific foundation for further utilization of Fructus Canarii.