Exopolysaccharide fraction from Pediococcus pentosaceus KFT18 induces immunostimulatory activity in macrophages and immunosuppressed mice.

AIMS: Exopolysaccharide fraction from Pediococcus pentosaceus KFT18 (PE-EPS), a lactic acid bacteria isolated from Kimchi (a Korean fermented vegetable product), was preliminary characterized and its immunostimulating effects were analysed. METHODS AND RESULTS: In this study, we used interferon-γ (IFN-γ)-primed RAW 264·7 macrophages and CD3/CD28-stimulated splenocytes to determine the immunotimulatory activities of PE-EPS. Upon exposure to PE-EPS, IFN-γ-primed RAW 264·7 macrophages showed significant increases in the expressions of inducible nitric oxide synthase (iNOS), tumour necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1ß. Molecular data using reporter gene assay and electrophoretic mobility shift assay (EMSA) revealed that PE-EPS upregulated transcriptional activity, DNA binding and the nuclear translocation of nuclear factor-κB (NF-κB). Furthermore, PE-EPS enhanced anti-CD3/CD28-specific proliferation and the productions of IL-2 and IFN-γ in primary splenocytes. In cyclophosphamide-induced immunosuppressed mice, pretreatment with PE-EPS (5, 15 or 45 mg kg(-1) day(-1), p.o.) increased thymus and spleen indices, and improved lymphocyte and neutrophil counts. CONCLUSION: PE-EPS stimulated the IFN-γ-primed macrophages and primary splenocytes to induce immune responses and improved the cyclophosphamide-induced immunosuppression in mice. SIGNIFICANCE AND IMPACT OF THE STUDY: The results in this study improved our understanding of immunostimulating activity of PE-EPS and supported its potential treatment option as a natural immunostimulant.

In vitro and in vivo immunostimulatory activity of an exopolysaccharide-enriched fraction from Bacillus subtilis.

AIMS: The aim of this study was to investigate the immunostimulatory effects of an exopolysaccharide-enriched fraction obtained from Bacillus subtilis J92 (B-EPS). METHODS AND RESULTS: To determine the immunostimulatory activities of B-EPS, we used IFN-γ-primed RAW 264.7 macrophages and CD3/CD28-stimulated splenocytes. Increases in the levels of NO and many cytokines, such as, TNF-α, IL-6, and IL-1ß, were observed in IFN-γ-primed RAW 264.7 macrophages by Griess reaction and ELISAs respectively. Using Western blotting and qRT-PCR, we found that B-EPS increased the protein and mRNA expressions of iNOS and the mRNA expressions of TNF-α, IL-6, and IL-1ß. A reporter gene assay and EMSA revealed that B-EPS up-regulated the transcriptional activity of NF-κB by increasing its DNA binding and nuclear translocation. Pretreatment with NF-κB inhibitors, that is, BAY11-7082 and PDTC, decreased NO production in IFN-γ-primed RAW 264.7 macrophages by B-EPS. Furthermore, B-EPS increased the proliferation of and cytokine (IL-2 and IFN-γ) production by CD3/CD28-stimulated splenocytes. In a cyclophosphamide-induced immunosuppressed mouse model, B-EPS (5, 15 or 45 mg kg(-1) , p.o.) restored thymus and spleen indices. B-EPS also inhibited cyclophosphamide-induced reductions in neutrophil and lymphocyte numbers. CONCLUSIONS: B-EPS improves immune function by regulating immunological parameters in IFN-γ-primed macrophages, CD3/CD28-stimulated splenocytes, and in cyclophosphamide-induced immunosuppressed mice. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests that the exopolysaccharides secreted by B. subtilis J92 could be used as immune stimulants.

Folding and stability of sweet protein single-chain monellin. An insight to protein engineering.

Engineered single-chain monellin (SCM) proteins were constructed by recombinant technology without disrupting the topology and sweet activity of native protein. Data from 8-anilinonaphthalene-1-sulfonic acid fluorescence, size-exclusion chromatography, and heteronuclear NMR strongly suggest the presence of a folding intermediate at 1.5 m GdnHCl for SCM protein. The structural feature of the folding intermediate from NMR data reveals that the secondary structures became mostly unstable, and protein experiences a dynamic equilibrium between native and unfolded state. All backbone amide protons exchange within 10 min, which imply that no stable hydrogen bonds exist in the secondary structural regions in the folding intermediate. From equilibrium unfolding and mutagenesis studies, the unfolding transition midpoints of mutant proteins gradually shifted toward lower denaturant concentration, indicating stability reductions of mutant proteins. Our results suggest that stability and folding pathways of SCM proteins could be regulated by a combined study of spectroscopy and mutagenesis, and these studies will provide useful information for understanding the folding kinetics of novel engineered proteins.

No touch pulse measurement by optical interferometry.

Arterial pulsatility was measured using an optical interferometer. As opposed to laser Doppler flow meters, the prototype system we evaluated can detect pulsation profiles of major arteries with potentially useful information including pulse wave velocity, profile of pulse pressure, etc.