Acetoin (AC) is a volatile platform compound with various potential industrial applications. AC contains two stereoisomeric forms: (3)-AC and (3)-AC. Optically pure AC is an important potential intermediate and widely used as a precursor to synthesize novel optically active materials. In this study, chiral (3)-AC production from -2,3-butanediol (-2,3-BD) was obtained using recombinant cells co-expressing-2,3-butanediol dehydrogenase (-2,3-BDH), NADH oxidase (NOX), and hemoglobin protein (VHB) from sp. T241,, and , respectively. The new biocatalyst of/pET--- was developed and the bioconversion conditions were optimized. Under the optimal conditions, 86.74 g/l of (3)-AC with the productivity of 3.61 g/l/h and the stereoisomeric purity of 97.89% was achieved from 93.73 g/l -2,3-BD using the whole-cell biocatalyst. The yield and productivity were new records for (3)-AC production. The results exhibit the industrial potential for (3)-AC production via whole-cell biocatalysis.
Inflammatory macrophages in colonic mucosa are the leading drivers of the pathology associated with inflammatory bowel disease (IBD). Here we examined whether gadolinium chloride (GdCl3), a macrophage selective inhibitor, would improve the course of 2,4,6-trinitro benzene sulfonic acid (TNBS) and dextran sodium sulfate (DSS)-induced colitis in mice and the potential mechanisms were investigated. By giving GdCl3 to colitis mice through intravenous or intrarectal route, we found that GdCl3 markedly ameliorated the colitis severity, including less weight loss, decreased disease activity index scores, and improved mucosal damage. To investigate the potential mechanisms, flow-cytometric analysis was performed to detect the proportion of mucosal macrophages in colon. The results showed that GdCl3 had no macrophage depletion effect in colonic mucosa, but significantly suppressed TNBS and DSS-induced TNFα, IL-1β and IL-6 secretions. Also, Western blotting analysis indicated that NF-κB p65 expression was significantly attenuated in the mucosa in colitis mice with GdCl3 treatment. Then, the anti-inflammatory activity of GdCl3 was confirmed in LPS-stimulated RAW 264.7 cells that GdCl3 might down-regulate the production of proinflammatory cytokines by macrophages through inhibition of the NF-κB signaling pathway. Therefore, intervention with mucosal inflammatory macrophages may be a promising therapeutic target in IBD.
A simple method is proposed for manufacturing the flexible III–V inverted metamorphic solar cells by low‐temperature transfer technology. Benefiting from the special low‐temperature adhesive and the Cu‐plated thin films, only one‐time bonding and extremely easy debonding are needed through the whole process and a negligible effect of residual stress can be obtained, which is critical to large‐size device fabrication. The optical model of light trapping and photon recycling based on the native textured back‐surface reflector of the flexible solar cell is constructed to design the antireflection coating. The flexible 4 in solar cells with a weight‐area density of only 169 g m−2 are successfully mass‐produced. The analysis of the individual subcells using optoelectronic reciprocity relation indicates that the GaAs middle subcell should be further optimized to improve the performance. The technique can be expected to achieve mass production of flexible high‐efficiency large‐size solar cells with low cost.
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