Assembly of selenium nanoparticles by protein coronas composed of yeast protease A

Superoxide Dismutase Catalyzed Size-Adjustable Selenium Nanoparticles in Saccharomyces boulardii

“…Under normal physiological conditions, PrA is located in the vacuoles of yeast via the Golgi-to-vacuole pathway, while under stress conditions via the constitutive secretory pathway or yeast autolysis, it can be released into the extracellular space . In addition, the expression of PrA is relatively stable without or under stress conditions, as determined by quantitative real-time PCR (qRT–PCR) . Nevertheless, at lower doses of selenite, there was an increase in the size of the BioSeNPs compared with that at higher doses.…”

“…In addition, the PrA coating serves the additional function of preventing other deleterious effects, effectively inhibiting the aggregation of SeNPs. This multifaceted approach enhances the overall stability and biocompatibility of selenium nanoparticles, underscoring their utility in diverse applications . Therefore, there is likely a balance between PrA and enzymes for synthesizing BioSeNPs.…”

“…The wild type (namely, BWT) and the best mutant (BMS) for accumulating selenium through atmospheric and room temperature plasma mutagenesis of S. boulardii were chosen for cultivation as previously reported. 13 The media used for seed (yeast extract peptone dextrose) and batch (inorganic salt) cultivation and growth conditions were the same as those used by Nie et al 8 Since the reduction in sodium selenite mainly occurs during the exponential and stable growth stages, the concentration of sodium selenite determines whether sodium selenite is reduced. 16 Therefore, to obtain smaller BioSeNPs, two strategies were utilized to optimize the conditions for adding sodium selenite using mutants: (1) adding different concentrations of sodium selenite (50 to 400 μg/mL, 50 interval) at the same time and (2) adding the optimized sodium selenite via strategy 1 at different times (0, 4, 8, 10, 12, and 14 h).…”

“…26 These findings suggest that a high expression of the sod1 gene can increase the activity of selenium oxidation−reduction reactions and that cellular metabolism reduces oxidative stress on selenium during the reduction process, leading to a faster rate of synthesizing BioSeNPs, which is consistent with the high yield of BioSeNPs produced by the obtained mutant in a previous study. 8 Since smaller and more stable BioSeNPs seem to exhibit greater biological activity, increasing the diameter of BioSeNPs decreases their antioxidant activity. 27 As the particle size decreases, the specific surface area increases, leading to the elevated generation of intra-and extracellular reactive oxygen species (ROS).…”

“…In a previous study, we obtained intracellular BioSeNPs coated with protease A (PrA), and the desired size of the PrAencapsulated BioSeNPs was approximately 100 nm. 8 To better understand the interactions between BioSeNPs and important factors such as coating proteins and enzymes that participate in synthesis, this work aimed to reveal the underlying mechanism by optimizing the conditions of S. boulardii mutants for accumulating smaller BioSeNPs and comparing the difference in transcription levels between mutant and wild-type strains based on transcriptome analysis. In summary, the probiotic S. boulardii embedded with intracellular BioSeNPs could be used in food/feed and biomedicine fields.…”