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81.
Yao Nie Yan Xu Hai Yan wang Na Xu Rong Xiao Zhi Hao sun 《Biocatalysis and Biotransformation》2008,26(3):210-219
An (R)-specific carbonyl reductase from Candida parapsilosis CCTCCM203011 (CprCR) was shown to catalyze the asymmetric reduction of 2-hydroxyacetophenone to (R)-1-phenyl-1,2-ethanediol (PED), which is a critical chiral building block in organic synthesis. The gene (rcr) encoding CprCR was cloned based on the amino acid sequences of tryptic fragments of the enzyme. Sequence analysis revealed that rcr is comprised of 1008 nucleotides encoding a 35 977 Da polypeptide, and shares similarity to proteins of the medium-chain dehydrogenase/reductase (MDR) superfamily. Recombinant rcr expressed in Escherichia coli showed a specific 2-hydroxyacetophenone-reducing activity. Using rcr expressing cells, (R)-PED was obtained by asymmetric reduction, which is complementary in enantiomeric configuration to (S)-PED obtained by using whole cells of C. parapsilosis. After optimization of reaction conditions, (R)-PED was produced at 95.5% enantiomeric excess with a yield of 92.6% when isopropanol was used for cofactor regeneration. 相似文献
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Yingshan Zhou Dongzhi Yang Xuanyue Gao Xiangmei Chen Qiang Xu Fengmin Lu Jun Nie 《Carbohydrate polymers》2009,75(2):293-298
Semi-interpenetrating polymer network (semi-IPN) hydrogels were prepared by UV irradiation of water-soluble N-carboxylethyl chitosan (CECS) and 2-hydroxyethyl methacrylate (HEMA) aqueous solutions in the presence of D-2959 as photoinitiator. Hydrogels were characterized by using scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and X-ray diffractometry (XRD). SEM showed that semi-IPN hydrogels displayed porous surface and therefore had high surface area. XRD indicated that CECS/poly (HEMA) semi-IPN hydrogels had amorphous structure. The thermal stability and equilibrium degree of swelling improved obviously with increase of CECS content. Differential scanning calorimetry (DSC) indicated that free water content increased with increase of CECS content while bonded water content decreased. Cytotoxicity results suggested that semi-IPN hydrogels had good biocompatibility. From these preliminary evaluations, it is possible to conclude that these materials have potential applications in the biomedical field. 相似文献
85.
Huang Nie Zhengwu Peng Ning Lao Hailong Dong Lize Xiong 《Neurochemical research》2013,38(8):1758-1767
Sevoflurane anesthesia in infant rats can result in long-term cognitive impairment, possibly by inhibiting neurogenesis. The hippocampus is critical for memory consolidation and is one of only two mammalian brain regions where neural stem cells (NSCs) are renewed continuously throughout life. To elucidate the pathogenesis of sevoflurane-induced cognitive dysfunction, we measured the effects of clinical sevoflurane doses on the survival, proliferation, and differentiation of hippocampal NSCs. Neural stem cells were isolated from Sprague–Dawley rat embryos, expanded in vitro, and exposed to sevoflurane at 0.5, 1, or 1.5 minimal alveolar concentration (MAC) for 1 or 6 h. Two days after treatment, cell viability, cytotoxicity, and apoptosis rate were estimated by WST-1 assay, lactate dehydrogenase (LDH) activity, and TdT-mediated dUTP-biotin nick end labeling (TUNEL), respectively, while proliferation rate was assessed by 5-ethynyl-2′-deoxyuridine (BrdU) incorporation and Ki67 staining. Differentiation was assayed 7 days after treatment by immunocytochemistry and Western blots of neuron and glial markers. The phosphorylation level of p44/42 extracellular regulated kinases (ERK1/2) was measured in the proliferation and differentiation phases respectively. Sevoflurane at 1 MAC or 1.5 MAC for 1 h increased viable cell number whereas a 6 h exposure at these same concentrations suppressed proliferation and promoted apoptotic death (P < 0.01). Sevoflurane had no effect on NSC differentiation, and a sub-clinical concentration (0.5 MAC) altered neither proliferation nor viability. The phosphorylation level of ERK1/2 increased after 1 h of 1 MAC or 1.5 MAC of sevoflurane exposure in the proliferation phase, but not in the differentiation phase. Brief (1 h) exposure to sevoflurane at clinical concentrations enhanced proliferation of cultured NSCs possibly mediated by ERK1/2, but a 6 h exposure suppressed proliferation and induced apoptosis. Prolonged sevoflurane exposure may decrease the self-renewal capacity of hippocampal NSCs, resulting in cognitive deficits. 相似文献
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Linc00483 as ceRNA regulates proliferation and apoptosis through activating MAPKs in gastric cancer 下载免费PDF全文
Defeng Li Meifeng Yang Aijun Liao Bing Zeng Diqun Liu Yuhong Yao Guangsheng Hu Xuanmin Chen Zhiqiang Feng Yanlei Du Youlian Zhou Jie He Yuqiang Nie 《Journal of cellular and molecular medicine》2018,22(8):3875-3886
Long non‐coding RNAs (lncRNAs) are important regulators of many cellular processes, and their aberrant expression and/or function is associated with many different diseases, including cancer. However, the identification of functional lncRNAs in gastric cancer is still a challenge. In this study, we describe a novel functional lncRNA, linc00483, that is upregulated and associated with tumorigenesis, tumour size, metastasis and poor prognosis in gastric cancer. In our study, linc00483 promoted gastric cancer cell proliferation, invasiveness and metastasis in vitro and in vivo. Mechanistically, upregulated expression of linc00483 in gastric cancer acts as a sponge to absorb endogenous tumour suppressor miR‐30a‐3p. Furthermore, it restores SPAG9 expression, which is negatively regulated by miR‐30a‐3p, and actives MAPK signaling pathway in gastric cancer cells. Thus, linc00483 is an oncogenic lncRNA in gastric cancer and targeting linc00483 or its pathway can potentially be useful in development of targeted therapies for patients with gastric cancer. Our results show that linc00483 is an important regulator in carcinogenesis and may be a useful biomarker to predict prognosis of gastric cancer patients. We believe our findings are novel and will be of interest to scientists working in many areas related to biomarkers in cancer. 相似文献
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Jun Hu Guohua Lv Shuguang Zhou Yucheng Zhou Bangxu Nie Hong Duan Yunfeng Zhang Xiaofeng Yuan 《PloS one》2015,10(5)
BackgroundOsteosarcoma is the most common primary bone malignancy in children and young adults. Increasing results suggest that discovery of microRNAs (miRNAs) might provide a novel therapeutical target for osteosarcoma.MethodsMiR-182 expression level in osteosarcoma cell lines and tissues were assayed by qRT-PCR. MiRNA mimics or inhibitor were transfected for up-regulation or down-regulation of miR-182 expression. Cell function was assayed by CCK8, migration assay and invasion assay. The target genes of miR-182 were predicated by bioinformatics algorithm (TargetScan Human).ResultsMiR-182 was down-regulated in osteosarcoma tissues and cell lines. Overexpression of miR-182 inhibited tumor growth, migration and invasion. Subsequent investigation revealed that TIAM1 was a direct and functional target of miR-182 in osteosarcoma cells. Overexpression of miR-182 impaired TIAM1-induced inhibition of proliferation and invasion in osteosarcoma cells.ConclusionsDown-expression of miR-182 in osteosarcoma promoted tumor growth, migration and invasion by targeting TIAM1. MiR-182 might act as a tumor suppressor gene whose down-regulation contributes to the progression and metastasis of osteosarcoma, providing a potential therapy target for osteosarcoma patients. 相似文献
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Production of chitinase from bacteria has distinct advantages over fungi, due to the formation of mycelia of fungi in the
later phase of fermentation. A novel chitinase-producing bacterial strain XJ-01 was isolated from the Yulu fishing field of
Changsha, Hunan province, China, by enrichment and spread-plate technique, sequentially. Physicochemical characterization
and 16S rRNA sequencing revealed that strain XJ-01 belongs to Serratia marcescens. By optimizing the fermentation condition based on L9(34) orthogonal experimental design, a maximal chitinase activity up to 15.36 U/ml was attained by that stain under the condition:
0.5% (NH4)2SO4 as the nitrogen source, 0.75% colloidal chitin as the carbon source, temperature of 32°C, time of 32 h and pH 8.0. 相似文献