Regio-selective glycosylation of mogroside IIIE by glycosyltransferase / 中国药科大学学报

@#Mogrosides, the main sweet components isolated from Siraitia grosvenorii, are a family of cucurbitane-type tetracyclic triterpenoid saponins. Given that the high sweetness, low calorie and excellent taste, mogrosides have become the important resource for the development of natural non-nutritive sweeteners. As reported, 11α-hydroxyl group in the structural skeleton of mogrosides was closely related to sweetness and taste, but it had not been confirmed experimentally. In this work, we used mogroside IIIE as a model compound, which was 300 times sweeter than 5% sucrose and tasted better, and modified its 11α-hydroxyl group through glycosyltransferase to elucidate the relations between structure and sweetness of mogroside compounds. The glycosyltransferase HXSW-GT-2 was obtained to regio-selectively glycosylate the 11α-hydroxyl group of mogroside IIIE through the screening of glycosyltransferase library. And then, the soluble expression of HXSW-GT-02 in Escherichia coli was efficiently achieved by optimizing the induction conditions. Subsequently, the yield of glycosylated mogroside IIIE(MG-IIIE-Glu)was increased to > 85% through optimizing reaction pH, temperature, UDP-G dosage and biocatalyst loading. The product MG-IIIE-Glu was bio-prepared at a 0. 5 L scale and the final purity was 97. 8%. A “mouth feel” test showed that MG-IIIE-Glu had no sweetness and displayed obvious bitterness through the comparison with mogroside IIIE and 5% sucrose. In conclusion, the function of the 11α-hydroxyl group of mogrosides in sweetness and taste was preliminarily elucidated which would be beneficial for the structural modification and development of mogroside sweeteners.

The Effectiveness of Visual Field C10-2 in the Early Detection of Glaucoma with Parafoveal Scotoma

PURPOSE: To identify the correspondence between the central sensitivity of several visual field (VF) tests and ganglion cell inner plexiform layer (GC-IPL) thickness in early glaucoma patients with parafoveal scotoma. METHODS: Fifty-seven eyes from 57 patients with glaucomatous optic neuropathy and parafoveal scotoma were analyzed using the standard automated perimetry (SAP) C10-2 test, the SAP C24-2 test, and the frequency doubling technology perimetry (FDT) C24-2 test. The correlation between the VF central sensitivity and the GC-IPL thickness from macular scans via optical coherence tomography was analyzed. RESULTS: The central sensitivity was 27.51 ± 5.43 dB, 27.39 ± 5.05 dB, and 22.09 ± 5.08 dB for SAP C24-2, SAP C10-2, and FDT C24-2, respectively. Mean GC-IPL thickness was 70.2 ± 8.5 µm. Using regression analysis, the value of log R² between the logarithmic central sensitivity and GC-IPL thickness was 0.498, and the linear R2 between the antilogarithmic central sensitivity and GC-IPL thickness in SAP C10-2 was 0.486, and both were statistically significant (p < 0.05). This relationship was stronger in early glaucoma patients compared to late glaucoma patients using SAP C10-2. CONCLUSIONS: The structure-function relationship between GC-IPL thickness and central sensitivity was better with SAP C10-2, especially in early glaucoma patients, compared to other VF modalities.

Structure and function of extracellular HMGB-1 / 医学研究生学报

HMGB-1, an ubiquitously expressed 25-KD nucleoprotein among mammals, belongs to the HMG family. Recent studies have identified that HMGB-1 is secreted by activated monocytes/macrophages via a non-classical ,vesicle-mediated secretory pathway. Extracellular HMGB-1 is an important proinflammatory cytokine. It participates in the pathogenesis of many diseases such as rheumatoid arthritis, sepsis , acute lung injury, and even leads animals death. Further studies of the mechanism and function of extracellular HMGB-1 may provide a novel strategy for the diagnosis and treatment of these diseases.