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Metabolic Engineering of Probiotic <i>Saccharomyces boulardii</i>
Liu, Jing-Jing,Kong, In Iok,Zhang, Guo-Chang,Jayakody, Lahiru N.,Kim, Heejin,Xia, Peng-Fei,Kwak, Suryang,Sung, Bong Hyun,Sohn, Jung-Hoon,Walukiewicz, Hanna E.,Rao, Christopher V.,Jin, Yong-Su American Society for Microbiology 2016 Applied and environmental microbiology Vol.82 No.8
<P>Saccharomyces boulardii is a probiotic yeast that has been used for promoting gut health as well as preventing diarrheal diseases. This yeast not only exhibits beneficial phenotypes for gut health but also can stay longer in the gut than Saccharomyces cerevisiae. Therefore, S. boulardii is an attractive host for metabolic engineering to produce biomolecules of interest in the gut. However, the lack of auxotrophic strains with defined genetic backgrounds has hampered the use of this strain for metabolic engineering. Here, we report the development of well-defined auxotrophic mutants (leu2, ura3, his3, and trp1) through clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9-based genome editing. The resulting auxotrophic mutants can be used as a host for introducing various genetic perturbations, such as overexpression or deletion of a target gene, using existing genetic tools for S. cerevisiae. We demonstrated the overexpression of a heterologous gene (lacZ), the correct localization of a target protein (red fluorescent protein) into mitochondria by using a protein localization signal, and the introduction of a heterologous metabolic pathway (xylose-assimilating pathway) in the genome of S. boulardii. We further demonstrated that human lysozyme, which is beneficial for human gut health, could be secreted by S. boulardii. Our results suggest that more sophisticated genetic perturbations to improve S. boulardii can be performed without using a drug resistance marker, which is a prerequisite for in vivo applications using engineered S. boulardii.</P>
Fei Yuchen,Ye Xiaofang,Al-Baldawy Aseel Shaker,Wan Jing,Lan Jinshen,Zhao Jingtian,Wang Ziyun,Qu Shanzhi,Hong Rongdun,Guo Shengshi,Huang Shengli,Li Shuping,Kang Junyong 한국물리학회 2022 Current Applied Physics Vol.44 No.-
Noble metal particles have been embedded in semiconductors to improve photocatalysis efficiently, but the high cost made this approach difficult to apply widely in industry. Herein titanium dioxide/reduced graphene oxide (TiO2/rGO) nanowires in a core-shell structure were prepared. The physicochemical properties and photocatalytic performance of the specimen were characterized in comparison with TiO2 and TiO2/Pt nanowires. The rGO layer and Pt nanoparticles increased chemical states of the components, reduced bandgap energy of the nanowires, enhanced visible light absorption, improved conductance and capacitance significantly. The methylene blue as catalyzed by TiO2/Pt and TiO2/rGO nanowires was degraded to 7.9% and 8.4% in an hour, but retained 25.7% by the TiO2 nanowires. The properties and function of TiO2/rGO nanowires were close to those of TiO2/Pt nanowires, while the rGO price was much lower than that of Pt, which was of great significance for the photocatalytic application of TiO2 heterojunction materials in industry.
Varistor and dielectric properties of Cr2O3 doped SnO2eZn2SnO4 composite ceramics
Guo-Zhong Zang,Feng-Zi Zhou,Jing-Xiao Cao,Xiao-Fei Wang,Zhao-Wu Wang,Li-Ben Li,Guo-Rong Li 한국물리학회 2014 Current Applied Physics Vol.14 No.12
Cr2O3 doped SnO2eZn2SnO4 composite ceramics were prepared by traditional ceramic processing and the varistor, dielectric properties were investigated. With increasing Cr2O3 content, the breakdown electrical field EB increases from 11 to 92 V/mm and the relative dielectric constant εr measured at 1 kHz, 50 C decreases from 11,028 to 3412, respectively. The barrier height fB about 0.8e0.84 eV and the decreasing of SnO2 grain size suggest that the varistor behavior with high εr is originated from SnO2 eSnO2 or SnO2eZn2SnO4 grain boundary. In the dielectric spectra lower than 1 kHz, a dielectric peak is presented and depressed with increasing bias voltage. Similarly, at high temperature, the dielectric constant also presents a dielectric peak in the temperature spectra and the peak becomes faint with increasing frequency. The exhibition of the dielectric peak is thought to be attributed to the conduction of grain boundary since it is accompanied by the sharp increase of dielectric loss. In addition, a dielectric relaxation with the activation energy about 0.4e0.5 eV was observed in the temperature range of 20 e100 C. Based on the results, the formation mechanism of Schottky barriers at grain boundaries and the varistor behavior with high dielectric constant are well understood.
Liu Jing,Ke Pingyang,Guo Haokun,Gu Juan,Liu Yanling,Tian Xin,Wang Xuefeng,Xiao Fei 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-
The pathophysiological mechanisms underlying epileptogenesis are poorly understood but are considered to actively involve an imbalance between excitatory and inhibitory synaptic transmission. Excessive activation of autophagy, a cellular pathway that leads to the removal of proteins, is known to aggravate the disease. Toll-like receptor (TLR) 7 is an innate immune receptor that regulates autophagy in infectious and noninfectious diseases. However, the relationship between TLR7, autophagy, and synaptic transmission during epileptogenesis remains unclear. We found that TLR7 was activated in neurons in the early stage of epileptogenesis. TLR7 knockout significantly suppressed seizure susceptibility and neuronal excitability. Furthermore, activation of TLR7 induced autophagy and decreased the expression of kinesin family member 5 A (KIF5A), which influenced interactions with γ-aminobutyric acid type A receptor (GABAAR)-associated protein and GABAARβ2/3, thus producing abnormal GABAAR-mediated postsynaptic transmission. Our results indicated that TLR7 is an important factor in regulating epileptogenesis, suggesting a possible therapeutic target for epilepsy.
폴리(스티렌-이소부틸렌-스티렌) 삼중블록 공중합체의 합성, 분석 및 혈액적합성
Wen Li Guo,Ping Ren,Yi Bo Wu,Shu Xin Li,Jing Mao,Fei Xiao,Kang Li 한국고분자학회 2011 폴리머 Vol.35 No.1
The synthesis of well-defined poly(styrene-b-isobutylene-b-styrene) (SIBS) triblock copolymers was accomplished by cationic sequential block copolymerization of isobutylene (IB) with styrene (St) using 1,4-di(2-chloro-2-propyl)benzene (DCC)/TiCl4 /2,6-di-tert-butylpyridine(DtBP) as an initiating system in methyl chloride (CH3Cl)/methylcyclohexane(MeChx) (50/50 v/v) solvent mixture at -80 ℃. The triblock copolymers exhibited excellent thermoplastic and elastomeric characteristics. Tensile strengths and Shore hardness increased with increasing polystyrene (PS) content, while elongation at break decreased. The blood-compatibility of SIBS was assessed by SEM observation of the platelet adhesion, blood clotting time and haemolysis ratio. The haemolysis ratios were below 5% which met the medical materials standard. The platelet adhesion test further indicated that SIBS block copolymers had a good blood compatibility.
Xu-Guang Guo,Li-Min Xie,Xin Yin,Tian-Ao Xie,Jian-Wen Su,Qin Huang,Jing-Hao Zhang,Yin-Fei Huang 연세대학교의과대학 2022 Yonsei medical journal Vol.63 No.1
Purpose: Acute respiratory viral infections pose significant morbidity and mortality, making it essential to diagnose respiratory viral infections rapidly. In this study, the diagnostic efficacy of the Luminex xTAG Respiratory Virus Panel (RVP) FAST v2 test was evaluated on respiratory viral infections. Materials and Methods: Information was retrieved from electronic databases, including Embase, Web of Science, PubMed, and Cochrane Library, for systematic review. Studies that fulfilled predefined inclusion criteria were included. After the extraction of information, statistical software was utilized for quality evaluation, data analysis, and assessment of publication bias. Results: Eighty groups in fourfold tables from nine articles were included to perform statistical analyses. Therein, the mean specificity and mean sensitivity of Luminex xTAG RVP FAST v2 test for the detection of respiratory viral infections were 0.99 (0.98–0.99) and 0.88 (0.87–0.90), respectively. Additionally, the negative and positive likelihood ratios were 0.14 (0.11–0.19) and 87.42 (61.88–123.50), respectively. Moreover, the diagnostic odds ratio and area under the curve of summary receiver operating characteristic were 714.80 and 0.9886, respectively. Conclusion: The Luminex xTAG RVP FAST v2 test could be a reliable and rapid diagnostic method for multiple respiratory viral infections.
Yong Sun,Jing Ping Zhang,Fei Guo,Lian Zhang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.9
Hydrochar was produced from hydrothermal treatment of corn straw black liquor. Response surface methodology (RSM) and the central composite design (CCD) were employed for determination of optimal char with maximum Pb2+ removal capacity. The operational parameters such as hydrothermal temperature (oC), duration (min) and solid liquid ratio (LSR) were chosen as independent variables in CCD. The statistical analysis indicates that the effects of hydrothermal temperature, duration, LSR and combined effect of hydrothermal temperature and duration are all significant for the Pb2+ removal capacity. The optimal condition for achieving the maximum Pb2+ adsorption capacity is obtained as the following: hydrothermal temperature (205 oC), duration (28min), LSR (12) with Pb2+ removal capacity reaching 47mg/g. The BET specific surface area of char prepared at optimal conditions could reach 85m2/g.
Hong-xia Lu,Man He,Yuan-yuan Liu,Jing-fei Guo,Li-wei Zhang,Deliang Chen,Hai-long Wang,Hong-liang Xu,Rui Zhang 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.5
Glass-ceramic glazes have been prepared successfully via crystallization from blast-furnace slag (BFS), fly ash (FA) fluxed with potash feldspar and borax. The crystalline behavior of glass-ceramic glazes was investigated using differential thermal analysis and thermogravimetric analysis (DTA/TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results revealed that the major crystalline phases are anorthite (CaAl2Si2O8) and akermanite (Ca2MgSi2O7) and crystalline phases disperse well in glassy phases with a uniform size of 1 μm. Glass-ceramic glazes possess low density, low water absorption,perfect stain resistance, acid resistance and alkali resistance. The thermal expansion coefficient of glass-ceramic glazes is steady up to 800 oC with an average value of 7.2 × 10−6 /K. Final results suggest that BFS and FA have potential to be vitrified into economically and environmentally low-cost glass-ceramic glaze materials.
Fibulin2: a negative regulator of BMSC osteogenic differentiation in infected bone fracture healing
Li Shi-Dan,Xing Wei,Wang Shao-Chuan,Li You-Bin,Jiang Hao,Zheng Han-Xuan,Li Xiao-Ming,Yang Jing,Guo De-Bin,Xie Xiao-Yu,Jiang Ren-Qing,Fan Chao,Li Lei,Xu Xiang,Fei Jun 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-
Bone fracture remains a common occurrence, with a population-weighted incidence of approximately 3.21 per 1000. In addition, approximately 2% to 50% of patients with skeletal fractures will develop an infection, one of the causes of disordered bone healing. Dysfunction of bone marrow mesenchymal stem cells (BMSCs) plays a key role in disordered bone repair. However, the specific mechanisms underlying BMSC dysfunction caused by bone infection are largely unknown. In this study, we discovered that Fibulin2 expression was upregulated in infected bone tissues and that BMSCs were the source of infection-induced Fibulin2. Importantly, Fibulin2 knockout accelerated mineralized bone formation during skeletal development and inhibited inflammatory bone resorption. We demonstrated that Fibulin2 suppressed BMSC osteogenic differentiation by binding to Notch2 and inactivating the Notch2 signaling pathway. Moreover, Fibulin2 knockdown restored Notch2 pathway activation and promoted BMSC osteogenesis; these outcomes were abolished by DAPT, a Notch inhibitor. Furthermore, transplanted Fibulin2 knockdown BMSCs displayed better bone repair potential in vivo. Altogether, Fibulin2 is a negative regulator of BMSC osteogenic differentiation that inhibits osteogenesis by inactivating the Notch2 signaling pathway in infected bone.