A new fungal immunomodulatory protein (FIP-fve) has been isolated and purified from the edible golden needle mushroom (Flammulina velutipes). The apparent molecular mass of FIP-fve determined by SDS/PAGE agrees well with the value of 12704 Da calculated from its amino acid composition and sequence. The complete amino acid sequence of FIP-fve was elucidated by protein sequencing techniques. FIP-fve consists of 114 amino acid residues with an acetylated amino end, and lacks methionine, half-cystine and histidine residues. FIP-fve was able to hemagglutinate human red blood cells. The immunomodulatory activity of FIP-fve was demonstrated by its stimulatory activity toward human peripheral blood lymphocytes, and its suppression of systemic anaphylaxis reactions and local swelling of mouse footpads. FIP-fve was found to enhance the transcriptional expression of interleukin-2 and interferon-gamma.
We develop a novel nanohybrid showing a strong antibacterial activity on all of the tested pathogens, including methicillin-resistant Staphylococcus auerus and silver-resistant E. coli. The nanohybrid consists of silver nanoparticles (AgNPs) supported on 1 nm-thick silicate platelets (NSPs). The AgNP/NSP nanohybrid enables to encapsulate bacteria and triggers death signals from the cell membrane. The geographic shape of the NSPs concentrates AgNPs but impedes their penetration into attached cells, mitigating the detrimental effect of silver ion deposition in applied tissues. Moreover, the tightly tethered AgNPs on NSP surface achieve a stronger biocidal effect than silver nitrate, but bypassing Ag+ mechanism, on silver-resistant bacteria. This nanohybrid presents an effective and safe antimicrobial agent in a new perspective.
Silver nanoparticles (AgNPs) are known for their excellent antibacterial activities. The possible toxicity, however, is a major concern for their applications. Three types of AgNPs were prepared in this study by chemical processes. Each was stabilized by a polymer surfactant, which was expected to reduce the exposure of cells to AgNPs and therefore their cytotoxicity. The polymer stabilizers included poly(oxyethylene)-segmented imide (POEM), poly(styrene-co-maleic anhydride)-grafting poly(oxyalkylene) (SMA) and poly(vinyl alcohol) (PVA). The cytotoxicity of these chemically produced AgNPs to mouse skin fibroblasts (L929), human hepatocarcinoma cells (HepG2), and mouse monocyte macrophages (J774A1) was compared to that of physically produced AgNPs and gold nanoparticles (AuNPs) as well as the standard reference material RM8011 AuNPs. Results showed that SMA-AgNPs were the least cytotoxic among all materials, but cytotoxicity was still observed at higher silver concentrations (>30 ppm). Macrophages demonstrated the inflammatory response with cell size increase and viability decrease upon exposure to 10 ppm of the chemically produced AgNPs. SMA-AgNPs did not induce hemolysis at a silver concentration below 1.5 ppm. Regarding the antibacterial activity, POEM-AgNPs and SMA-AgNPs at 1 ppm silver content showed 99.9% and 99.3% growth inhibition against E. coli, while PVA-AgNPs at the same silver concentration displayed 79.1% inhibition. Overall, SMA-AgNPs demonstrated better safety in vitro and greater antibacterial effects than POEM-AgNPs and PVA-AgNPs. This study suggested that polymer stabilizers may play an important role in determining the toxicity of AgNPs.
Bitter foods are generally recognized as anti-inflammatory agents in traditional Chinese medicine. To verify the anti-inflammatory effects of some bitter compounds in foods or plants, five bitter compounds, aloperine, amygdalin, berberine, crotaline, and naringenin, were selected and added to primary mouse splenocytes in the absence or presence of lipopolysaccharide (LPS) under four different in vitro experimental models. Anti-inflammatory cytokine secretions such as interleukin (IL)-10 and pro-inflammatory cytokines such as IL-6 as well as tumor necrosis factor (TNF)-α were determined using enzyme-linked immunosorbent assay (ELISA). The results showed that all selected bitter compounds except amygdalin exhibited apparent cytotoxic effects. On the basis of changes in the secretion profiles between anti- and pro-inflammatory cytokines, the five selected bitter compounds demonstrated anti-inflammatory activities via modulating either IL-6/IL-10 or TNF-α/IL-10 ratios at noncytotoxic doses. Berberine and naringenin treatments showed the strongest potential for anti-inflammation among the five selected bitter compounds. Berberine especially displayed strong anti-inflammatory activity in both preventive and repair manners.
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