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151.
Yonghong Meng Guiru Dong Chen Zhang Yuanyuan Ren Yuling Qu Weifeng Chen 《Biotechnology letters》2016,38(4):673-679
Objective
To study the effect of Ca2+ on glutamate dehydrogenase (GDH) and its role in poly-γ-glutamic acid (γ-PGA) synthesis in Bacillus natto HSF 1410.Results
When the concentration of Ca2+ varied from 0 to 0.1 g/l in the growth medium of B. natto HSF 1410, γ-PGA production increased from 6.8 to 9.7 g/l, while GDH specific activity and NH4Cl consumption improved from 183 to 295 U/mg and from 0.65 to 0.77 g/l, respectively. GDH with α-ketoglutarate as substrate primarily used NADPH as coenzyme with a K m of 0.08 mM. GDH was responsible for the synthesis of endogenous glutamate. The specific activity of GDH remained essentially unchanged in the presence of CaCl2 (0.05–0.2 g/l) in vitro. However, the specific activity of GDH and its expression was significantly increased by CaCl2 in vivo. Therefore, the regulation of GDH and PGA synthesis by Ca2+ is an intracellular process.Conclusion
Calcium regulation may be an effective approach for producing γ-PGA on an industrial scale.152.
Qu Wei-Min Huang Zhi-Li Mochizuki Takatoshi Eguchi Naomi Chen Jiang-Fan Schwarzschild Michael A. Fink Stephen J. Urade Yoshihiro Hayaishi Osamu 《Sleep and biological rhythms》2016,2(1):S55-S55
Sleep and Biological Rhythms - 相似文献
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Which one of the two common reporter systems is more suitable for chemiluminescent enzyme immunoassay: alkaline phosphatase or horseradish peroxidase? 下载免费PDF全文
Songcheng Yu Fei Yu Lie Liu Hongquan Zhang Zhenzhong Zhang Lingbo Qu Yongjun Wu 《Luminescence》2016,31(3):888-892
Alkaline phosphatase and horseradish peroxidase are the most commonly used reporter systems in chemiluminescent enzyme immunoassay (CLEIA). Which one, therefore, would be better when establishing a CLEIA method for a new target substance? There was no standard answer. In this study, both reporters were compared systematically including luminescence kinetics, conjugation methods, optimal condition and detection performance, using two common drugs, SD‐methoxy‐pyrimidine and enrofloxacin, as determination objects. The results revealed that there was much difference between the luminescence kinetics of the two systems. However, there was little difference between these systems when detecting the same substance, including in optimal conditions and determination of performance. Both reporters were suitable for establishing chemiluminescent enzyme immunoassays. Therefore, the choice of alkaline phosphatase or horseradish peroxidase as the reporter system in chemiluminescent enzyme immunoassays depends on availability. Conversely, these two report systems could be applied in simultaneous analysis of multicomponents due to their different optical behaviors and similar performances. But attention should be paid to conjugation method and coating buffer, which affected the luminescent intensity of different determination targets. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
155.
Wenwen Zhang Lulu Cao Zijia Sun Jing Xu Lin Tang Weiwei Chen 《Cell cycle (Georgetown, Tex.)》2016,15(10):1344-1351
The F box protein Skp2 is oncogenic. Skp2 and Skp2B, an isoform of Skp2 are overexpressed in breast cancer. However, little is known regarding the mechanism by which Skp2B promotes the occurrence and development of breast cancer. Here, we determined the expression and clinical outcomes of Skp2 in breast cancer samples and cell lines using breast cancer database, and investigated the role of Skp2 and Skp2B in breast cancer cell growth, apoptosis and cell cycle arrest. We obtained Skp2 is significantly overexpressed in breast cancer samples and cell lines, and high Skp2 expression positively correlated with poor prognosis of breast cancer. Both Skp2 and Skp2B could promote breast cancer cell proliferation, inhibit cell apoptosis, change the cell cycle distribution and induce the increased S phase cells and therefore induce cell proliferation in breast cancer cells. Moreover, the 2 isoforms could both suppress PIG3 expression via independent pathways in the breast cancer cells. Skp2 suppressed p53 and inhibited PIG3-induced apoptosis, while Skp2B attenuated the function of PIG3 by inhibiting PHB. Our results indicate that Skp2 and Skp2B induce breast cancer cell development and progression, making Skp2 and Skp2B potential molecular targets for breast cancer therapy. 相似文献
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Lulu Hu Chen-hui Gao Chao Hong Qiao Zhong Xiao-Ming Gao 《Bioscience, biotechnology, and biochemistry》2016,80(2):257-263
Lactoferrin (LTF), a multifunctional glycoprotein of the transferrin family mainly found in exotic secretions in mammals, is an important defense molecule against not only microbial invasion but also tumors. It folds into two globular domains (N- and C-lobes) each containing an iron-binding site. The cationic antimicrobial peptide in N-lobe is known to exert anti-tumor effect via a non-receptor-mediated pathway. However, whether LTF C-lobe also contributes to its anti-tumor activity remains to be investigated. In this study, a human LTF fragment (amino acid residues 343–682) covering the C-lobe was expressed with a histidine tag in E. coli and the purified polypeptide refolded through a series of buffer changing procedure. The resultant recombinant protein caused significant growth arrest of breast carcinoma cells MDA-MB-231 in a dose- and time-dependent manner, evidently via induction of apoptosis of the cell. Our data suggest a positive role for the C-lobe of human LTF in controlling tumors in vitro. 相似文献