Severe choline deficiency induces alternative splicing aberrance in optimized duck primary hepatocyte cultures

Zhao Lulu,Cai Hongying,Wu Yongbao,Tian Changfu,Wen Zhiguo,Yang Peilong 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.11

Objective: Choline deficiency, one main trigger for nonalcoholic fatty liver disease (NAFLD), is closely related to lipid metabolism disorder. Previous study in a choline-deficient model has largely focused on gene expression rather than gene structure, especially sparse are studies regarding to alternative splicing (AS). In modern life science research, primary hepatocytes culture technology facilitates such studies, which can accurately imitate liver activity in vitro and show unique superiority. Whereas limitations to traditional hepatocytes culture technology exist in terms of efficiency and operability. This study pursued an optimization culture method for duck primary hepatocytes to explore AS in choline-deficient model. Methods: We performed an optimization culture method for duck primary hepatocytes with multi-step digestion procedure from Pekin duck embryos. Subsequently a NAFLD model was constructed with choline-free medium. RNA-seq and further analysis by rMATS were performed to identify AS events alterations in choline-deficency duck primary hepatocytes. Results: The results showed E13 (embryonic day 13) to E15 is suitable to obtain hepatocytes, and the viability reached over 95% by trypan blue exclusion assay. Primary hepatocyte retained their biological function as well identified by Periodic Acid-Schiff staining method and Glucose-6-phosphate dehydrogenase activity assay, respectively. Meanwhile, genes of alb and afp and specific protein of albumin were detected to verify cultured hepatocytes. Immunofluorescence was used to evaluate purity of hepatocytes, presenting up to 90%. On this base, choline-deficient model was constructed and displayed significantly increase of intracellular triglyceride and cholesterol as reported previously. Intriguingly, our data suggested that AS events in choline-deficient model were implicated in pivotal biological processes as an aberrant transcriptional regulator, of which 16 genes were involved in lipid metabolism and highly enriched in glycerophospholipid metabolism. Conclusion: An effective and rapid protocol for obtaining duck primary hepatocytes was established, by which our findings manifested choline deficiency could induce the accumulation of lipid and result in aberrant AS events in hepatocytes, providing a novel insight into various AS in the metabolism role of choline. Objective: Choline deficiency, one main trigger for nonalcoholic fatty liver disease (NAFLD), is closely related to lipid metabolism disorder. Previous study in a choline-deficient model has largely focused on gene expression rather than gene structure, especially sparse are studies regarding to alternative splicing (AS). In modern life science research, primary hepatocytes culture technology facilitates such studies, which can accurately imitate liver activity <i>in vitro</i> and show unique superiority. Whereas limitations to traditional hepatocytes culture technology exist in terms of efficiency and operability. This study pursued an optimization culture method for duck primary hepatocytes to explore AS in choline-deficient model.Methods: We performed an optimization culture method for duck primary hepatocytes with multi-step digestion procedure from Pekin duck embryos. Subsequently a NAFLD model was constructed with choline-free medium. RNA-seq and further analysis by rMATS were performed to identify AS events alterations in choline-deficency duck primary hepatocytes.Results: The results showed E13 (embryonic day 13) to E15 is suitable to obtain hepatocytes, and the viability reached over 95% by trypan blue exclusion assay. Primary hepatocyte retained their biological function as well identified by Periodic Acid-Schiff staining method and Glucose-6-phosphate dehydrogenase activity assay, respectively. Meanwhile, genes of <i>alb</i> and <i>afp</i> and specific protein of albumin were detected to verify cultured hepatocytes. Immunofluorescence was used to evaluate purity of hepatocytes, presenting up to 90%. On this base, choline-deficient model was constructed and displayed significantly increase of intracellular triglyceride and cholesterol as reported previously. Intriguingly, our data suggested that AS events in choline-deficient model were implicated in pivotal biological processes as an aberrant transcriptional regulator, of which 16 genes were involved in lipid metabolism and highly enriched in glycerophospholipid metabolism.Conclusion: An effective and rapid protocol for obtaining duck primary hepatocytes was established, by which our findings manifested choline deficiency could induce the accumulation of lipid and result in aberrant AS events in hepatocytes, providing a novel insight into various AS in the metabolism role of choline.

Effect of welding residual stress on operating stress of nuclear turbine low pressure rotor

Tan Long,Zhao Liangyin,Zhao Pengcheng,Wang Lulu,Pan Jiajing,Zhao Xiuxiu 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.8

The purpose of this study is to investigate the effect of welding residual stress on operating stress in designing a nuclear turbine welded rotor. A two-dimensional axisymmetric finite element model is employed to calculate the residual stress before and after post weld heat treatment (PWHT), and then the superposition of residual stress after PWHT and operating stress at normal speed and overspeed were discussed. The investigated results show that operating stress can be affected significantly by welding residual stress, and the distribution trend of superposition stress at the weld area is mainly determined by welding residual stress. The superposition of residual stress and operating stress is linear superposition, and the hoop stress distribution of superposition stress is similar with the distribution of residual stress. With the increasing overspeed, the distribution pattern of the hoop superimposed stress remains almost unchanged, while the stress level increases

Oxygen vacancies assisted LaFeO3 derived from metal organic frameworks endows a practical HCHO sensor with excellent sensing characteristics

Lulu Guo,Shushu Zhao,Guimao Yang,Lifeng Gao,Yanhong Wu,Xuguang Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-

Perovskite oxide semiconductors have attracted tremendous interest in gas sensing due to their promisingproperties of tunable active sites, excellent catalytic ability and good structural stability. Nevertheless, the rapid synthesis of perovskite oxides and controlled regulation of their surface oxygenvacancies remains a great challenge. Herein, we report a novel metal–organic frameworks (MOFs) selftemplatestrategy for the rapid and large-scale preparation of LaFeO3 nanoparticles (MLaFeO3) withabundant oxygen vacancies. Benefit from the introduction of oxygen vacancies, the resultantMLaFeO3 gas sensor exhibit excellent formaldehyde (HCHO) sensing performance at a low operatingtemperature of 160 C, including high sensitivity (Rg/Ra = 8.9 @ 100 ppm), fast response/recovery rate(53 s/32 s), low detection limit (1 ppm) and excellent selectivity. Comprehensive density functional theory(DFT) calculation and spectral characterizations reveal that oxygen vacancies play a vital role in promotingthe adsorption and activation of O2 and HCHO molecules, and accelerate the chemical reaction onthe sensing materials surface. Most importantly, it proves the promising application of MLaFeO3 sensorin food safety assessment. This work not only provides a simple strategy for constructing oxygen vacanciesenriched LaFeO3, but also demonstrates the application potential of LaFeO3-based gas sensors in thefield of formaldehyde detection.

Study on Hot Deformation Behavior and Bending Forging Process of 7075 Aluminum Alloy

Lulu Li,Rui Ma,Jun Zhao,Ruixue Zhai 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.5

7075 aluminum alloy forged elbow has a wide range of application, but its deformation law is very complex. Its forging process parameters are difficult to control, so it is becoming a difficulty in practical production. In this paper, aiming at the forging parameters of 7075 aluminum alloy, the thermal simulation compression tests with different deformation parameters were cleverly designed, and the optimal forming range of 7075 aluminum alloy was obtained by combining theoretical calculation, microstructure and simulation. The results showed that: 7075 aluminum alloy forming process parameters range was 350∘C≤T≤450∘C+0.01/s≤ε˙≤0.78/s, T = 400 °C + 0.78/s≤ε˙≤1.0/s(except 400 °C + 0.1/s). The optimum forging parameters were: forging temperature 420 °C, forging speed 10 mm/s.

One-Pot Synthesis of Nanodendritic PtIr Alloy with High Electrochemical Activity for Ethylene Glycol Oxidation

Xuedong Gao,Lulu Liu,Qiyu Wang,Kun Qi,Zhao Jin,WEITAO ZHENG,XIAOQIANG CUI 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.2

Nanodendritic Pt-based bimetallic alloys are one promising catalyst with three-dimensional (3D) networks structure composed of integrating branches for electrochemical catalytic reaction. We successfully synthesized dendrites Pt6Ir4 alloy with small size of 20 nm in oleylamine. The dendritic Pt6Ir4 alloy are characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrochemical tests suggest that the as-prepared dendritic Pt6Ir4 alloy exhibits greatly enhanced ethylene glycol oxidation reaction (EGOR) activity than commercial Pt/C with high EGOR mass activity, anti-poisoning and stability.

Metal-Free Photocatalysts C3N3S3 and its Polymers: Solubility in Water and Application in Benzylic Alcohols Oxidation Under Visible Light

Liming Chen,Lulu Zhao,Jie Xu,Jinlin Long,Linxi Hou 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.8

Metal-free photocatalysts trithiocyanuric acid (C3N3S3) and its polymers were one-step synthesized and used for selective aerobic oxidation of benzyl alcohol under visible light. The S–S bridged C3N3S3 polymers showed higher oxidation activity with increasing polymerization time and reached a maximum at 40 h. As a major factor, catalysts' solubility in water at different temperatures (from 298.15K to 368.15 K) was measured at atmospheric pressure. The obtained data were correlated by polynomial empirical equation and modified Apelblat equation, respectively. Experimental results proved that the solubility of C3N3S3 and its polymers increased with increasing temperature. The solubility of C3N3S3 polymers with lower polymerization degree (DP) were better than that of parent C3N3S3 owing to the hydrophilicity caused by a low symmetry and disorder structure, whereas the higher DP could lead to the decrease of polymer solubility and further affect the photocatalytic activity. Thermodynamic properties of the solution system including the enthalpy (△H0S) and heat capacity (c0p) were calculated by the modified Apelblat equation.

Endogenous leptin promotes autophagy in EBSS-induced PFCs

Deling Jiao,Zhen Yang,Lulu Wang,Binyue Hu,Jing Wang,Anyong Xu,Wenmin Cheng,Baoyu Jia,Yubo Qing,Hong-Ye Zhao,Hong-Jiang Wei 한국통합생물학회 2019 Animal cells and systems Vol.23 No.5

Leptin is an important adipokine and plays a vital role in animals. However, the role of leptin in the autophagic response of pig fibroblast cells (PFCs) has not been fully elucidated. In this study, we investigated the relationship between leptin and autophagy as well as underlying molecular basis. We found that PFCs treated with EBSS could secrete leptin, and the leptin concentration in the supernatant of leptin transgenic PFCs was higher than that of WT PFCs. We found an increase in LC3-II protein level and a decrease in p62 protein level in treated leptin transgenic PFCs compared with treated WT PFCs. Meanwhile, we observed an increase of autophagosomes by transmission electron microscopy and an enhancement of the accumulation of LC3 puncta in the cytoplasm of treated leptin transgenic PFCs, and these effects were further augmented by Baf A1 treatment. Furthermore, we detected the expression levels of 7 autophagy signaling pathway genes and 17 autophagy-related (ATG) genes by q-PCR. We found that between the two types of EBSS-treated cells 3 genes expression pattern were significantly different among the 7 autophagy signaling pathway genes and 8 genes expression pattern were significantly differernt among the ATG genes. These results indicated that leptin may promote autophagy and involving the downregulation of FOXO1 and LMNA genes via an unknown pathway which causes the upregulation of the 4 genes and the downregulation of 4 genes.

Structural and Functional Analyses of Periplasmic 5′-Methylthioadenosine/<i>S</i>-Adenosylhomocysteine Nucleosidase from <i>Aeromonas hydrophila</i>

Xu, Yongbin,Wang, Lulu,Chen, Jinli,Zhao, Jing,Fan, Shengdi,Dong, Yuesheng,Ha, Nam-Chul,Quan, Chunshan American Chemical Society 2017 Biochemistry Vol.56 No.40

<P>The Gram-negative, rod-shaped bacterium Aeromonas hydrophila has two multifunctional 5/-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) enzymes, MtaN-1 and MtaN-2, that differ from those in other bacteria. These proteins are essential for several metabolic pathways, including biological methylation, polyamine biosynthesis, methionine recycling, and bacterial quorum sensing. To gain insight into how these two proteins function, we determined four high-resolution crystal structures of MtaN-1 in its apo form and in complex with the substrates S-adenosyl-L-homocysteine, S'-methylthioadenosine, and 5'-deoxyadenosine. We found that the domain structures were generally similar, although slight differences were evident. The crystal structure demonstrates that AhMtaN-1 has an extension of the binding pocket and revealed that a tryptophan in the active site (Trp199) may playa major role in substrate binding, unlike in other MTAN proteins. Mutation of the Trp199 residue completely abolished the enzyme activity. Trp199 was identified as an active site residue that is essential for catalysis. Furthermore, biochemical characterization of AhMtaN-1 and AhMtaN-2 demonstrated that AhMtaN-1 exhibits inherent trypsin resistance that is higher than that of AhMtaN-2. Additionally, the thermally unfolded AhMtaN-2 protein is capable of refolding into active forms, whereas the thermally unfolded AhMtaN-1 protein does not have this ability. Examining the different biochemical characteristics related to the functional roles of AhMtaN-1 and AhMtaN-2 would be interesting. Indeed, the biochemical characterization of these structural features would provide a structural basis for the design of new antibiotics against A. hydrophila.</P>

The effect of mechanical inhomogeneity in microzones of welded joints on CTOD fracture toughness of nuclear thick-walled steel

Tan Long,Li Songyang,Zhao Liangyin,Wang Lulu,Zhao Xiuxiu 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.11

This study employs the microshear test method to examine the local mechanical properties of narrow-gap welded joints, revealing the mechanical inhomogeneity by evaluating the microshear strength, stress‒strain curves, and failure strain. On this basis, the influence of weld joints micromechanical inhomogeneity on the crack tip opening displacement (CTOD) fracture toughness is investigated. From the root weld layer to the cover weld layer, the fracture toughness at the center of the weld seam demonstrates an increasing trend, with the experimental and calculated CTOD values showing a good correspondence. The microproperties of the welded joints significantly impact the load-bearing capacity and fracture toughness. During the deformation process of the “low-matching” microregions, the plastic zone expansion is hindered by the surrounding microregion strength constraints, thus reducing the fracture toughness. In contrast, during the deformation of the “high-matching” microregions, the surrounding microregions absorb some of the loading energy, partially releasing the concentrated stress at the crack tip, which in turn increases the fracture toughness.

A Comparative Study on the Insulation Ageing of 10 kV XLPE Cable via Accelerated Electrical Test and Accelerated Water Tree Test

Li Weiwei,Zheng Wenyue,Ren Lulu,Li Huan,Zhao Xuetong,Wang Can,Li Jianying 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.1

Medium and high voltage XLPE cables were widely used in urban distribution network. The electric-thermal eff ect of the cable conductor and water in the running environment are two important factors that cause ageing of cable insulating material. In this work, accelerated electrical test (AET) and accelerated water tree test (AWTT) on 10 kV XLPE cable were carried out for 1440 h, 2880 h and 4320 h, respectively. The physicochemical and dielectric properties of both aged and unaged XLPE samples were tested. Physicochemical investigation of Fourier Transform Infrared (FTIR) spectroscopy and X-Ray Diff raction (XRD) show that higher carbonyl groups index, and lower crystallinity of the XLPE insulating materials were generated in AWTT process than that in AET process. The thermal decomposition process of the AWTT XLPE are complicated, presenting a multi-peak phenomenon in the diff erential thermogravimetry (DTG) curve. The insulating strength of the samples after AWTT is monotonically decreased from 23.03 kV to 21.74 kV with ageing time. The dielectric properties show that the permittivity and dielectric loss of AWTT samples increased more severely than that of AET samples, with a new dielectric relaxation peak appearing at around 100 Hz. The combination of physicochemical and dielectric results reveals that AWTT process leads to more serious degradation for XLPE insulating materials. A schematic illustration is given to elucidate the development of micro defects in XLPE during the AET and AWTT processes.