Improved Isopropanol Productivity by Using Lipid Metabolic Pathway in Oleaginous Yeast Yarrowia lipolytica

Xiaoyu SHI,Hyeon Min PARK,Myeong-Eun LEE,Sung Ok HAN 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10

Isopropanol is converted industrially to propylene, which is important not only as a fuel but also as a backbone chemical for bioplastics. One of high stress tolerant yeasts, Yarrowia lipolytica is an oleaginous strain possessing relatively high native acetyl-CoA levels. Here, we genetically engineered a Y. lipolytica strain, which is expected to increase the yield of isopropanol. Malonyl-CoA is a major substrate exhibiting a high synthesis rate and high concentration in a lipid metabolic pathway. When the acetoacetyl-CoA synthase gene (nphT7) synthesizing acetoacetyl-CoA from malonyl-CoA and acetyl-CoA is used, isopropanol productivity can be expected to increase the yield of isopropanol. This experiment showed that 300 ㎎/L of isopropanol was produced under the shaking flasks cultivation condition, representing two-fold increase in isopropanol titer compared to previous studies. Taken together, this is the first report of the isopropanol production by using lipid metabolic pathway in Y. lipolytica.

The Progress of Research on Chinese Stabilized Fertilizer

Shi Yuanliang,Wang Lingli,Shi Xiaoyu,Li Jie,Sun Yi 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

The effect of Reynolds number on the elliptical cylinder wake

Xiaoyu Shi,Md. Mahbub Alam,Honglei Bai,Hanfeng Wang 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.30 No.5

This work numerically investigates the effects of Reynolds number ReD (= 100 - 150), cross-sectional aspect ratio AR = ( 0.25 -1.0), and attack angle α (= 0 - 90) on the forces, Strouhal number, and wake of an elliptical cylinder, where ReD is based on the freestream velocity and cylinder cross-section height normal to the freestream flow, AR is the ratio of the minor axis to the major axis of the elliptical cylinder, and α is the angle between the cylinder major axis and the incoming flow. At ReD = 100, two distinct wake structures are identified, namely ‘Steady wake’ (pattern I) and ‘Karman wake followed by a steady wake (pattern II)’ when AR and α are varied in the ranges specified. When ReD is increased to 150, an additional wake pattern, ‘Karman wake followed by secondary wake (pattern III)’ materializes. Pattern I is characterized by two steady bubbles forming behind the cylinder. Pattern II features Karman vortex street immediately behind the cylinder, with the vortex street transmuting to two steady shear layers downstream. Inflection angle αi = 32, 37.5 and 45 are identified for AR = 0.25, 0.5 and 0.75, respectively, where the wake asymmetry is the greatest. The αi effectively distinguishes the dependence on α and AR of force and vortex shedding frequency at either ReD. In Pattern III, the Karman street forming behind the cylinder is modified to a secondary vortex street. At a given AR and α, ReD = 150 renders higher fluctuating lift and Strouhal number than ReD = 100.

Effects of the Helicobacter pylori Virulence Factor CagA and Ammonium Ion on Mucins in AGS Cells

Xiaoyu Zhang,Ding Shi,Yong-pan Liu,Wu-jie Chen,Dong Wu 연세대학교의과대학 2018 Yonsei medical journal Vol.59 No.5

Purpose: To investigate the effects of Helicobacter pylori (H. pylori)-CagA and the urease metabolite NH4 + on mucin expression inAGS cells. Materials and Methods: AGS cells were transfected with CagA and/or treated with different concentrations of NH4CL. Mucingene and protein expression was assessed by qPCR and immunofluorescence assays, respectively. Results: CagA significantly upregulated MUC5AC, MUC2, and MUC5B expression in AGS cells, but did not affect E-cadherin andMUC6 expression. MUC5AC, MUC6, and MUC2 expression in AGS cells increased with increasing NH4 + concentrations untilreaching a peak level at 15 mM. MUC5B mRNA expression in AGS cells (NH4 + concentration of 15 mM) was significantly higherthan that at 0, 5, and 10 mM NH4 + . No changes in E-cadherin expression in AGS cells treated with NH4 + were noted, except at 20mM. The expression of MUC5AC, MUC2, and MUC6 mRNA in CagA-transfected AGS cells at an NH4 + concentration of 15 mM wassignificantly higher than that at 0 mM, and decreased at higher concentrations. The expression of MUC5B mRNA increased withincreases in NH4 + concentration, and was significantly higher compared to that in untreated cells. No significant change in the expressionof E-cadherin mRNA in CagA-transfected AGS cells was observed. Immunofluorescence assays confirmed the observedchanges. Conclusion: H. pylori may affect the expression of MUC5AC, MUC2, MUC5B, and MUC6 in AGS cells via CagA and/or NH4 + , butnot E-cadherin.

Iron-doped chitosan microsphere for As(III) adsorption in aqueous solution: Kinetic, isotherm and thermodynamic studies

Xiaoyu Lin,Leli Wang,Shi Jiang,Longzhe Cui,Gui-Ping Wu 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.7

Iron-doped chitosan microsphere was prepared successfully and employed for effective adsorption of As(III). The results showed that the adsorption capacity benefited from the increase of iron content, and the maximum adsorption capacity was achieved at pH=8. According to the study of adsorption kinetics, adsorption rate was controlled by liquid film diffusion at a lower rotational speed, while it was controlled by chemical reaction rate at a higher rotational speed. The Freundlich and Temkin models exhibited a better fit to adsorption isotherm data, which indicated the adsorption of As(III) on iron-doped chitosan microsphere was chemisorption and the active sites of adsorbents were non-uniform distributed. Adsorption process was a spontaneous exothermic reaction because its ΔG and ΔH were negative. In presence of cations (Cd2+, Pb2+ or Zn2+) in solution, the iron-doped chitosan microsphere also showed the significant removal of As(III). However, the existence of anions (NO3 , SO4 2 or PO4 3) inhibited the As(III) removal at different level. PO4 3 showed the most significant side effects on the removal of As(III) by iron-doped chitosan microsphere. The used iron-doped chitosan adsorbent can be effectively regenerated using 1.0mol·L1 NaOH solution, and the adsorption efficiency decreased only 15.69% after being reused three times. The results of XPS, FT-IR showed that the adsorption was mainly achieved by the coordination interaction between As (III) and doped Fe in adsorbent.

CARBON DEPOSIT INCINERATION DURING ENGINE FLAMEOUT USING NON-THERMAL PLASMA INJECTION

Xiaoyu Pu,Yixi Cai,Yunxi Shi,Jing Wang,Linbo Gu,Jing Tian,Runlin Fan 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.3

−In order to investigate the influence of initial regeneration temperatures on diesel particulate filter (DPF) regeneration, an experimental study of DPF regeneration was implemented using a dielectric barrier discharge (DBD) reactor, aided by exhaust waste heat after engine flameout. DPF trapping characteristics and carbon deposit mass were discussed to facilitate further data analysis and calculation. DPF regeneration was then investigated by comparison analysis of deposit removal mass, backpressure drop, and internal temperature change. The results revealed that a large amount of particulate matter (PM) was deposited in DPF with a high filtration efficiency of about 90 %. The deposit removal rate and percentage drop of the backpressure both maximized at the initial temperature of 100 oC. During DPF regeneration, the sharp rise of internal temperature indicated vigorous PM incineration and high CO2 emission. The results successfully demonstrated DPF regeneration using non-thermal plasma injection during engine flameout, and prominent heat durability was achieved in this method.

Concentrations of Calcium-binding Protein and Bone Gla-protein in Culture Medium and CaBP mRNA Expression in Osteoblasts of Broiler Chickens

Guo, Xiaoyu,Yan, Sumei,Shi, Binlin,Feng, Yongmiao Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.2

This study was conducted to determine the effects of excess vitamin A on alkaline phosphatase (ALP) activity, contents of calcium-binding protein (CaBP), bone gla-protein (BGP) in culture medium and CaBP mRNA expression in chicken osteoblasts in vitro. Osteoblastic cells in the tibia from 1-day-old Arbor Acre broiler chickens were isolated using enzyme digestion. The subconfluenced cells were divided into eight treatments with six replicates in each treatment and cultured in a medium containing either vehicle or different levels of vitamin A (0, 0.2, 0.6, 1.0, 2.0, 5.0, 10.0 and $20.0\;{\mu}g$/ml), and the control received an equivalent volume of ethanol. The incubation lasted 48 h. The results showed that vitamin A down-regulated ALP activity in the culture medium as well as CaBP mRNA expression of osteoblasts in a linear dose-dependent manner (p = 0.124 and p<0.10, respectively), and suppressed the contents of BGP and CaBP in the culture medium in a quadratic dose-dependent manner (p<0.05 and p<0.10, respectively) with increasing addition of vitamin A. The addition of 0-$0.2\;{\mu}g$/ml vitamin A to the culture medium increased ALP activity, BGP and CaBP contents as well as CaBP mRNA expression compared with other groups, but positive effects of vitamin A tended to be suppressed when vitamin A was increased to $1.0\;{\mu}g$/ml, and adverse effects occurred when vitamin A was increased to 10.0-$20.0\;{\mu}g$/ml. These results implied that there was a threshold level of vitamin A inclusion beyond which inhibitory effects occurred, and the mechanism by which overdose of vitamin A reduced bone growth in chickens was probably reduced osteoblastic cell activity, and inhibited expression of CaBP mRNA and CaBP secretion.

A Two-DNA Methylation Signature to Improve Prognosis Prediction of Clear Cell Renal Cell Carcinoma

Shanping Shi,Shazhou Ye,Xiaoyue Wu,Mingjun Xu,Renjie Zhuo,Qi Liao,Yang Xi 연세대학교의과대학 2019 Yonsei medical journal Vol.60 No.11

Purpose: Effective biomarkers and models are needed to improve the prognostic prospects of clear cell renal cell carcinoma(ccRCC). The purpose of this work was to identify DNA methylation biomarkers and to evaluate the utility of DNA methylationanalysis for ccRCC prognosis. Materials and Methods: An overview of genome-wide methylation of ccRCC tissues derived from The Cancer Genome Atlas(TCGA) database was download for analysis. DNA methylation signatures were identified using Cox regression methods. The potentialclinical significance of methylation biomarkers acting as a novel prognostic markers was analyzed using the Kaplan–Meiermethod and receiver operating characteristic (ROC) curves. Results: This study analyzed data for 215 patients with information on 23171 DNA methylation sites and identified a two-DNAmethylation signature (cg18034859, cg24199834) with the help of a step-wise multivariable Cox regression model. The area underthe curve of ROCs for the two-DNA methylation signature was 0.819. The study samples were stratified into low- and high-risk classificationsbased on an optimal threshold, and the two groups showed markedly different survival rates. Moreover, the two-DNAmethylation marker was suitable for patients of varying ages, sex, stages (I and IV), and histologic grade (G2). Conclusion: The two-DNA methylation signature was deemed to be a potential novel prognostic biomarker of use in increasingthe accuracy of predicting overall survival of ccRCC patients.

Variation in the quantity and composition of phosphorus accumulating organisms in activated sludge driven by nitrate-nitrogen

Wang Xiaoling,Shi Chunyan,Pan Wenbo,Lu Hai,Zhang Xiaoyu 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.7

Anaerobic/anoxia sequencing batch reactor (A/ASBR) system was used to analyze the quantity and composition of each branch of phosphorus accumulating organisms (PAOs) in activated sludge under different nitrate-nitrogen (NO 3 − -N) concentrations by using real-time quantitative polymerase chain reaction (PCR) technology. The study determined whether NO 3 − -N and its concentration change were the main driving factors for the variation of the quantity and composition of each branch of PAOs. The results show that with the increase of NO 3 − -N concentration from 10 mg/L to 40 mg/L, the number of bacterial 16S rRNA genes in the A/ASBR reactor changed slightly at 6.81×1011–7.53×1011 copies/g dry sludge. The number of PAO genes (Acc 16S rRNA) increased from 1.98×1011 to 3.53×1011 copies/g dry sludge, and the total number of ppk1 genes increased from 1.25×1011 to 3.59×1011 copies/g dry sludge. Additionally, the number of polyphosphate kinase (ppk) genes in Accumulibacter branch IA, IIC and IID was high, and the changes were positively related to the concentration of NO 3 − -N, while the number of branches in IIA, IIB and IIF was very low. The dosing concentration of NO 3 − -N was the main driving factor for the change of PAOs and their branch number and composition in the A/ASBR reactor.

The Mechanism of Rockbolt in the Jointed Rock Under Uniaxial Tension

Shen Zhou,Xiaoyu Ji,Li-Ping Li,Hong-liang Liu,Chun Zhu,Hongyun Fan,Qi Zhang,Caihua Shi,Xutong Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11

In this research, the rockbolt mechanism of a jointed rock mass under uniaxial tension was systematically revealed with a laboratory test and a numerical simulation. It was found that the rockbolt rock mass experienced five stages under uniaxial tension, the densification stage, elastic stage, plastic deformation stage, progressive debonding stage, and complete debonding stage. The stress-strain curve and ultimate tensile strength of a rockbolt rock mass were analyzed by taking the rockbolt spacing and rockbolt angle as variables. It was found that the improvement effect of the reduction of the rockbolt spacing on the ultimate tensile strength was limited. When the rockbolt spacing was reduced to a certain limit, the stress concentration area between adjacent rockbolts was connected and destroyed, resulting in the increase of the rockbolt rock strength becoming smaller, and even having a downward trend. The increase of the rockbolt angle led to the change of the stress mode and failure mode of the whole structure, and the ultimate tensile strength first increased and then decreased. The optimal rockbolt angle was between 60° and 70°. It is worth noting that there was an obvious mechanical occlusion between the thread on the rockbolt surface and the rock mass, resulting in the multi-stage step-down characteristic of the stress-strain curve in the complete debonding stage. The results of this study can provide a reference for the design and construction of similar projects.