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( Xiao Jie Cheng ),( Xu Ming Wang ),( Tian Lei Qiu ),( Mei Yuan ),( Jiang Uang Sun ),( Jun Lian Gao ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.11
A novel esterase gene, est01, was successfully unearthed from a biogas digester microbiota metagenomic library. The 1,194 bp est01 gene encodes a protein of 44,804 Da (designated Est01). The amino acid sequence of Est01 shows only moderate (33%) identity to a lipase/ esterase. Phylogenetic analysis and biochemical characterization confirmed that Est01 is a new member of family VIII esterases. The purified Est01 from recombinant Escherichia coli BL21 (DE3) showed high hydrolytic activity against short-chain fatty acid esters, suggesting that it is a typical carboxylesterase rather than a lipase. Furthermore, the Est01 was even active at 10°C (43% activity remained), with the optimal temperature at 20°C, and had a broad pH range from 5.0 to 10.0, with the optimal pH of 8.0. These properties suggest that Est01 is a cold-adaptive esterase and could have good potential for low-temperature hydrolysis application.
Jie Deng,Jianjun Zhao,Xiao Zhao,Jianle Yu,Chun Lei,Minlee Lee,Runqiu Huang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.4
It is important to account for the poor ecological environment of weak seasonal permafrost regions while developing a suitable ground improvement technique. As an organic non-polluting material, glutinous rice slurry improves the unconfined compressive strength of the soil through induction and synergy with lime. The Qinghai-Tibet Plateau has cold weather, large temperature differences between day and night, and a fragile ecological environment. Once damaged, it is extremely difficult to recover. This study investigates the effects of glutinous rice slurry on the unconfined compressive strength (UCS), failure mode, and microstructure of lime-treated seasonally frozen soil subjected to freeze–thaw cycles. Organic glutinous rice slurry with concentrations of 0, 2, 4, 6, and 8% was added to soil specimens that were treated with 10% lime and subjected to 0, 1, 3, 6, and 10 freeze–thaw cycles. In tests, the addition of glutinous rice pulp could increase the UCS of the soil by up to 40%. The first freeze-thaw cycle has the greatest impact on the UCS of the soil sample, with a decrease of 6 – 15%. Glutinous rice slurry can reduce the degradation effects of freeze-thaw cycles by increasing the contact area between soil particles. In a comprehensive evaluation under test conditions, a glutinous rice slurry concentration of 4% led to optimal results. It revealed the change characteristics of the microstructure under the action of freeze-thaw cycles, which has a good corresponding relationship with the macroscopic mechanical properties. The results can provide reference value for the application of glutinous rice slurry in the modification of subgrade soil in seasonal permafrost areas.
Spatial Regionalization on Surface Ozone in the Yangtze River Delta of China
Lei Tong,Hang Xiao,Hui Yi,Yu Liu,Jie Zheng,Cenyan Huang,Mengmeng He 한국기상학회 2022 Asia-Pacific Journal of Atmospheric Sciences Vol.58 No.2
In order to better understand the tempo-spatial characteristics of surface ozone (O3) on the regional scale of Yangtze River Delta (YRD), China, cluster analysis was applied to surface O3 monitored from 2016 to 2017 at 110 state-controlled stations. Eight spatial regions with distinct patterns of O3 variations were identified. The exceedances over the Grade I (100 μg/m3) andGrade II (160μg/m3) National Ambient Air Quality Standard of maximum daily average 8 h O3 (MDA8 O3) varied within 99~192 and 1~41 days, respectively, for different subregions. The central and east YRD were the most polluted subregions with higher incidence of O3 episodes, while the southwest and southeast YRD were relatively clean. The spatial disparity of O3 over YRD was strongly affected by local emissions, with larger precursor emissions contributing to higher frequencies of O3 pollution and larger amplitudes of temporal variations. The regionalO3 pollution mainly occurred in spring, with higher peaks ofMDA8O3 being observed duringApril ~May for most subregions. While for east YRD, O3 pollution was most serious in summer, when its monthly MDA8 O3 reached the highest value (141.0 μg/m3). During thewhole study period, the spatial differences of weekly/monthly amplitudes ofMDA8O3 were similar to those of NO2 among the eight subregions, indicating the significant influence of NO2 on O3 over YRD on the yearly timescale. This influence was especially evident in warm seasons for the coastal subregions, where O3 production was controlled by NOx. While for the west inland subregion, O3was less affected by NO2 variation, indicating a NOx-saturated characteristic of O3 formation.
Jie Fan,Meng-Yan Yu,Tong-da Lei,Yong-Heng Wang,Fu-Yuan Cao,Xiao Qin,Yong Liu 한국조직공학과 재생의학회 2018 조직공학과 재생의학 Vol.15 No.2
A rapid freezing/lyophilizing/reinforcing process is suggested to fabricate reinforced keratin/hydroxyapatite (HA) scaffold with improved mechanical property and biocompatibility for tissue engineering. The keratin, extracted from human hair, and HA mixture were rapidly frozen with liquid nitrogen and then lyophilized to prepare keratin/HA laminar scaffold. The scaffold was then immersed in PBS for reinforcement treatment, and followed by a second lyophilization to prepare the reinforced keratin/HA scaffold. The morphology, mechanical, chemical, crystal and thermal property of the keratin/HA scaffold were investigated by SEM, FTIR, XRD, DSC, respectively. The results showed that the keratin/HA scaffold had a high porosity of 76.17 ± 3%. The maximum compressive strength and compressive modulus of the reinforced scaffold is 0.778 and 3.3 MPa respectively. Subcutaneous implantation studies in mice showed that in vivo the scaffold was biocompatible since the foreign body reaction seen around the implanted scaffold samples was moderate and became minimal upon increasing implantation time. These results demonstrate that the keratin/HA reinforced scaffold prepared here is promising for biomedical utilization.
Effect of Light with Different Wavelengths on Nostoc flagelliforme Cells in Liquid Culture
( Yu Jie Dai ),( Jing Li ),( Shu Mei Wei ),( Nan Chen ),( Yu Peng Xiao ),( Zhi Lei Tan ),( Shi Ru Jia ),( Nan Nan Yuan ),( Ning Tan ),( Yi Jie Song ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.4
The effects of lights with different wavelengths on the growth and the yield of extracellular polysaccharides of Nostoc flagelliforme cells were investigated in a liquid cultivation. N. flagelliforme cells were cultured for 16 days in 500 ml conical flasks containing BG11 culture medium under 27 μmol·m-2·s-1 of light intensity and 25oC on a rotary shaker (140 rpm). The chlorophyll a, phycocyanin, allophycocyanin, and phycoerythrin contents in N. flagelliforme cells under the lights of different wavelengths were also measured. It was found that the cell biomass and the yield of polysaccharide changed with different wavelengths of light. The biomass and the yield of extracellular polysaccharides under the red or violet light were higher than those under other light colors. Chlorophyll a, phycocyanin, and allophycocyanin are the main pigments in N. flagelliforme cells. The results showed that N. flagelliforme, like other cyanobacteria, has the ability of adjusting the contents and relative ratio of its pigments with the light quality. As a conclusion, N. flagelliforme cells favor red and violet lights and perform the complementary chromatic adaptation ability to acclimate to the changes of the light quality in the environment.
Characterization of SiC/C Nanocomposite Powders Synthesized by Arc-Discharge
Zhou, Lei,Yu, Jie Yi,Gao, Jian,Wang, Dong Xing,Gan, Xiao Rong,Xue, Fang Hong,Huang, Hao,Dong, Xing Long Korean Society of Microscopy 2015 Applied microscopy Vol.45 No.4
In this paper, three carbon sources, i.e., solid graphite, gaseous CH4 and liquid ethanol, and one solid silicon source were employed to synthesize SiC/C nanocomposite powders by arc-discharge plasma. The processing conditions such as the component ratios of raw materials, atmospheric gases, etc. were adjusted for controllable synthesis of the nanopowders. It is indicated that both of solid graphite and silicon can be co-evaporated and reacted to form nanophases of cubic ${\beta}$-SiC with ~50 nm in mean size and a little free graphite; the carbon atoms decomposed from gaseous $CH_4$ favor to combine with the evaporated silicon atoms to form the dominant SiC nanophase; liquid carbon source of ethanol can also be used to harvest the main ${\beta}$-SiC and minor 6H-SiC phases in the assembly of nanoparticles. The as-prepared SiC/C nanocomposite powders were further purified by a heat-treatment in air and their photocatalytic performances were then greatly improved.
Zhang Jie,Lin Xiao-Tong,Yu Hong-Qiang,Fang Lei,Wu Di,Luo Yuan-Deng,Zhang Yu-Jun,Xie Chuan-Ming 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-
Metastatic hepatocellular carcinoma (HCC) is the most lethal malignancy and lacks effective treatment. FBXL6 is overexpressed in human hepatocellular carcinoma (HCC), but whether this change drives liver tumorigenesis and lung metastasis in vivo remains unknown. In this study, we aimed to identify FBXL6 (F-Box and Leucine Rich Repeat Protein 6) as a key driver of HCC metastasis and to provide a new paradigm for HCC therapy. We found that elevated FBXL6 expression in hepatocytes drove HCC lung metastasis and was a much stronger driver than Kras mutation (KrasG12D/+;Alb-Cre), p53 haploinsufficiency (p53+/-) or Tsc1 loss (Tsc1fl/fl;Alb-Cre). Mechanistically, VRK2 promoted Thr287 phosphorylation of TKT and then recruited FBXL6 to promote TKT ubiquitination and activation. Activated TKT further increased PD-L1 and VRK2 expression via the ROS-mTOR axis, leading to immune evasion and HCC metastasis. Targeting or knockdown of TKT significantly blocked FBXL6-driven immune evasion and HCC metastasis in vitro and in vivo. Notably, the level of active TKT (p-Thr287 TKT) was increased and was positively correlated with the FBXL6 and VRK2 expression levels in HCC patients. Our work provides novel mechanistic insights into FBXL6-driven HCC metastasis and suggests that targeting the TKT-ROS-mTOR-PD-L1/VRK2 axis is a new paradigm for treating patients with metastatic HCC with high FBXL6 expression.
Anomalous magnetization jumps in granular Pb superconducting films
Zhang An-Lei,Jiang Wan-Yan,Chen Xing-Hong,Zhang Xiao-Ke,Lu Wen-Lai,Chen Fei,Feng Zhen-Jie,Cao Shi-Xun,Zhang Jin-Cang,Ge Jun-Yi 한국물리학회 2022 Current Applied Physics Vol.35 No.-
In granular superconductors, the grain boundaries are closely related to the vortex dynamics and the macroscopic superconducting properties. In our research, Pb films with different grain sizes were prepared by tuning the substrate temperature. With the grain size decreasing, Pb films are prone to feature the anomalous magnetization jumps in the M − T curves, while in the M − H curves flux avalanche happens. Both phenomena appear in the same region of the H − T phase diagram and thus are considered to have the same origin. The further theoretical analysis shows that with grain size decreasing the pinning mechanism evolves from a mixed δTc and δl pinning to the δl pinning mechanism. The results shed light on the study of pinning mechanism for granular superconductors and is beneficial to the potential application of manipulating vortex pinning by regulation of intrinsic defects.