Corynebacterium glutamicum is one of the well-studied industrial strain that is used for the production of nucleotides and amino acids. Recently, it has also been studied as a possible producer of organic acids such as succinic acid, based on its ability to produce organic acids under an oxygen deprivation condition. In this study, we conducted the optimization of medium components for improved succinate production from C. glutamicum under an oxygen deprivation condition by Plackett-Burman design and applied a response surface methodology. A Plackett-Burman design for ten factors such as glucose, ammonium sulfate, magnesium sulfate, potassium phosphate (K2HPO4 and KH2PO4), iron sulfate, manganese sulfate, biotin, thiamine, and sodium bicarbonate was applied to evaluate the effects on succinate production. Glucose, ammonium sulfate, magnesium sulfate, and dipotassium phosphate were found to have significant influence on succinate production, and the optimal concentrations of these four factors were sequentially investigated by the response surface methodology using a Box-Behnken design. The optimal medium components obtained for achieving maximum concentration of succinic acid were as follows: glucose 10 g/l, magnesium sulfate 0.5 g/l, dipotassium phosphate (K2HPO4) 0.75 g/l, potassium dihydrogen phosphate (KH2PO4) 0.5 g/l, iron sulfate 6 mg/l, manganese sulfate 4.2 mg/l, biotin 0.2 mg/l, thiamine 0.2 mg/l, and sodium bicarbonate 100 mM. The parameters that differed from a normal BT medium were glucose changed from 40 g/l to 10 g/l, dipotassium phosphate (K2HPO4) 0.5 g/l changed to 0.75 g/l, and ammonium sulfate ((NH4)2SO4) 7 g/l changed to 0 g/l. Under these conditions, the final succinic acid concentration was 16.3 mM, which is about 1.46 fold higher than the original medium (11.1 mM) at 24 h. This work showed the improvement of succinate production by a simple change of media components deduced from sequential optimization.
ObjectivesAmong the inflammatory mediators, phorbol 12-myristate 13-acetate (PMA) is associated with the regulation of MUC5B expression in the airway epithelial cells. Epigallocatechin-3-gallate (EGCG) is the major component of green tea extract. The biological activity of EGCG includes reduction of cholesterol and antioxidant activity, as well as anti-inflammatory effect. However, the precise action mechanism of anti-inflammatory effect of EGCG in the airway epithelial cells has not been fully defined. This study investigates the effect and the brief signaling pathway of EGCG on PMA-induced MUC5B expression in the airway epithelial cells.MethodsIn NCI-H292 airway epithelial cells, the effect and signaling pathway of EGCG on MUC5B expression were investigated using real-time polymerase chain reaction analysis, enzyme immunoassay, immunohistochemical analysis, gelatin zymography assay, and immunoblot analysis.ResultsIn NCI-H292 airway epithelial cells, PMA induced MUC5B expression, phosphorylation of p38 mitogen-activated protein kinase (MAPK), and matrix metalloproteinase-9 (MMP-9) expression and protein activity. EGCG significantly decreased PMA-induced MUC5B expression, phosphorylation of p38 MAPK, and MMP-9 expression and protein activity. SB203580 (p38 MAPK inhibitor) significantly decreased PMA-induced MMP-9 expression. In addition, SB203580 and MMP-9 I (MMP-9 inhibitor) significantly decreased PMA-induced MUC5B expression.ConclusionThese results suggest that EGCG down-regulates PMA-induced MUC5B expression through the p38 MAPK dependent MMP-9 signaling pathway in human airway epithelial cells.
Influenza B virus remains a major cause of respiratory diseases worldwide. Because of limited epidemiological and genetic data, the local and global transmission patterns of influenza B virus are not fully understood. Here we report the molecular and phylogenetic characterization of 163 influenza B virus isolates from pediatric inpatients with influenza-like illness in the winter of 2011-2012 in South Korea. Analysis of haemagglutinin and neuraminidase genes of the influenza B isolates revealed that both B/Victoria (62 %) and B/Yamagata lineages (38 %) co-circulated during that influenza season, and a considerable number of the isolates carried several amino acid substitutions in the four major antigenic epitopes of their haemagglutinin protein.
As the recent rise of immune checkpoint inhibitors has resulted in durable clinical outcomes in cancer patients, the need for a newer and more widely effective target for immunotherapy has been vigorously sought in the field; T cell immunoreceptor with Ig and ITIM domain (TIGIT) is an immune checkpoint molecule expressed on CD8+ T cells, CD4+ T cells, NK cells, and regulatory T cells (Treg). TIGIT induces exhaustion of effector T cells (Teff) and NK cells in the tumor microenvironment via engagement with its ligand PVR (CD155) which is dominantly expressed on malignant tumor cells. After initial screening processes from a synthetic library, MG1131 clone was chosen based on the strongest binding affinity to human TIGIT and the superior PVR-blocking activity. MG1131 was cross-reactive with the cynomolgus monkey TIGIT, but not with the mouse TIGIT. Our in vitro efficacy data demonstrated that MG1131 activated NF-κB signaling in T cells, and enhanced NK-mediated tumor killing activities in a PVR-dependent manner. In vitro Treg suppression assays showed that MG1131 inhibited immunosuppressive functionality of Treg, leading to restoration of proliferation and IFN-γ secretion capacities of Teff even in the presence of Treg. In addition, expression levels of TIGIT on CD8+ T cells from PBMCs of cancer patient samples were higher compared with other immune inhibitory molecules such as PD-1, Tim-3, CTLA-4, or LAG-3, and the blockade of TIGIT by MG1131 resulted in increased IFN-γ secretion. Thus, our data indicate that MG1131 is a promising candidate for cancer immunotherapy by modulating NK and T cell functions. Citation Format: Jeewon Lee, Munkyung Kim, Hye-mi Nam, Joong Hyuk Sheen, Eun Jung Song, Hye In Yum, So Jung Lim, Hye-Young Park. MG1131, a novel TIGIT-targeting monoclonal antibody, enhances anti-tumor immune responses by modulating NK and T cell activity [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2230.
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