Acetylation of Smc3 by Eco1 Is Required for S Phase Sister Chromatid Cohesion in Both Human and Yeast

Zhang, Jinglan,Shi, Xiaomin,Li, Yehua,Kim, Beom-Jun,Jia, Junling,Huang, Zhiwei,Yang, Tao,Fu, Xiaoyong,Jung, Sung Yun,Wang, Yi,Zhang, Pumin,Kim, Seong-Tae,Pan, Xuewen,Qin, Jun Elsevier 2008 Molecular cell Vol.31 No.1

<P><B>Summary</B></P><P>Sister chromatid cohesion is normally established in S phase in a process that depends on the cohesion establishment factor Eco1, a conserved acetyltransferase. However, due to the lack of known in vivo substrates, how Eco1 regulates cohesion is not understood. Here we report that yeast Eco1 and its human ortholog, ESCO1, both acetylate Smc3, a component of the cohesin complex that physically holds the sister chromatid together, at two conserved lysine residues. Mutating these lysine residues to a nonacetylatable form leads to increased loss of sister chromatid cohesion and genome instability in both yeast and human. In addition, we clarified that the acetyltransferase activity of Eco1 is essential for its function. Our study thus identified a molecular target for the acetyltransferase Eco1 and revealed that Smc3 acetylation is a conserved mechanism in regulating sister chromatid cohesion.</P>

Bubble formation in a step-emulsification microdevice: hydrodynamic effects in the cavity

Zhiwei Zhang,Zhongdong Wang,Fengrui Bao,Mengyu Fan,Shaokun Jiang,Chunying Zhu,Youguang Ma,Taotao Fu 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.94 No.-

This study focuses on the generation of bubbles in a step-emulsification microdevice via a two-anglephotography method. It's found that the bubble generation mechanism is controlled by the interfacialtension, below a critical capillary number; while controlled by viscous force, inertial force and thedisturbance induced by the bubble swarm, above the critical capillary number. From the two-anglephotography method, a model is established for predicting the bubble size, by taking into account of thedynamic contact angle between gas-liquid interface and wall, and the hydrodynamic feedback of thecavity on bubble formation via the quantification of resistance by the volume fraction of gas in the cavity.

An Approximate Equivalence Based on process Algebra and Numerical Computation and for Differential Semi-algebraic Hybrid Systems

Zhiwei Zhang,Jinzhao Wu,HouWen Liu 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.10

In the paper, approximate ready trace equivalence for differential semi-algebraic hybrid system is proposed. The equivalence can be used to optimize differential semialgebraic hybrid system. The Concept is proposed on the basis of concrete process algebra and numerical analysis theory. In the approximate ready trace equivalence definition, we consider a cut operator for a polynomial and partial approximation for polynomial. Then we get a strict equivalence between two polynomials. Its advantage is that the new polynomial approximation method overcomes the drawback that traditional approximation method is not transitive, which can be used for automatic reasoning. In order to judge the two differential semi-algebraic hybrid system is equivalent, the axiom system for the approximate ready trace equivalence of differential semi-algebraic hybrid system is presented. This axiom system is a complete axiom system.

Effects of the resultant force due to two-phase density difference on droplet formation in a step-emulsification microfluidic device

Zhiwei Zhang,Mengyu Fan,Qianqiao Wang,Huaiyu Li,Chunying Zhu,Youguang Ma,Taotao Fu 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

This study focuses on the influence of the resultant force caused by the density difference of the twophases on the droplet generation process in a step-emulsification microfluidic device. Threedimensionalvisualization is used to observe the characteristics of droplet generation. According to thedifference in droplet generation form, it can be divided into drip generation mode and suspended generationmode. In the suspended generation mode, the droplets are more inclined to the formation process ofthe expansion of the ellipsoid, whose size in the horizontal direction is larger than the vertical direction;while in the drip generation mode, the shape of the droplet is opposite. The control stage of the dropletgeneration under various operating conditions is determined. As the viscosity of the dispersed phaseincreases, the control stage of the suspended generation mode is the necking stage, and the control stageof the drip generation mode changes from the first stage of three-dimensional expansion to the neckingstage. The model of the droplet generation is proposed by combining mechanical analysis and experimentaltesting data, and the droplet size prediction formula is thereby obtained.

Cytosolic escape of mitochondrial DNA triggers cGAS-STING-NLRP3 axis-dependent nucleus pulposus cell pyroptosis

Zhang Weifeng,Li Gaocai,Luo Rongjin,Lei Jie,Song Yu,Wang Bingjin,Ma Liang,Liao Zhiwei,Ke Wencan,Liu Hui,Hua Wenbin,Zhao Kangcheng,Feng Xiaobo,Wu Xinghuo,Zhang Yukun,Wang Kun,Yang Cao 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Low back pain (LBP) is a major musculoskeletal disorder and the socioeconomic problem with a high prevalence that mainly involves intervertebral disc (IVD) degeneration, characterized by progressive nucleus pulposus (NP) cell death and the development of an inflammatory microenvironment in NP tissue. Excessively accumulated cytosolic DNA acts as a damage-associated molecular pattern (DAMP) that is monitored by the cGAS-STING axis to trigger the immune response in many degenerative diseases. NLRP3 inflammasome-dependent pyroptosis is a type of inflammatory programmed death that promotes a chronic inflammatory response and tissue degeneration. However, the relationship between the cGAS-STING axis and NLRP3 inflammasome-induced pyroptosis in the pathogenesis of IVD degeneration remains unclear. Here, we used magnetic resonance imaging (MRI) and histopathology to demonstrate that cGAS, STING, and NLRP3 are associated with the degree of IVD degeneration. Oxidative stress induced cGAS-STING axis activation and NLRP3 inflammasome-mediated pyroptosis in a STING-dependent manner in human NP cells. Interestingly, the canonical morphological and functional characteristics of mitochondrial permeability transition pore (mPTP) opening with the cytosolic escape of mitochondrial DNA (mtDNA) were observed in human NP cells under oxidative stress. Furthermore, the administration of a specific pharmacological inhibitor of mPTP and self-mtDNA cytosolic leakage effectively reduced NLRP3 inflammasome-mediated pyroptotic NP cell death and microenvironmental inflammation in vitro and degenerative progression in a rat disc needle puncture model. Collectively, these data highlight the critical roles of the cGAS-STING-NLRP3 axis and pyroptosis in the progression of IVD degeneration and provide promising therapeutic approaches for discogenic LBP.

Static and Seismic Experimental Study of Novel Prefabricated Beam-Column Joints with Elongated-Hole Brackets

Zhang Zhiwei,Li Dong,Wang Huajie,Li Songling,Qian Hongliang,Bi Yanhua,Wang Guoxing,Jin Xiaofei,Fan Feng 한국강구조학회 2024 International Journal of Steel Structures Vol.24 No.1

To enhance the structural connectivity of prefabricated steel frame systems and augment their construction effi ciency, this study introduces an innovative prefabricated joint design tailored for square steel columns and H-beams characterized by varying beam heights. This study includes both static loading tests and seismic tests performed on full-scale joints featuring two diff erent beam heights. This investigation involved a comprehensive analysis of the static and seismic performance of the joints, employing various performance metrics such as ultimate load capacities, ultimate rotation angles, hysteresis curves, skeleton curves, stiff ness degradation curves, and ductility coeffi cients, in alignment with established structural codes and standards. The results indicate that the plasticity of the H-beam is fully developed, exhibiting a relative slip phenomenon. Additionally, the joints demonstrate commendable rotational capacity, with hysteresis curves consistently manifesting an inverse S-shape and exhibiting noteworthy stiff ness degradation. Furthermore, the comparison with the unimproved joint shows that the novel joint, in addition to being easy to construct, has better ductility and energy dissipation capacity. The results of the study will provide a technical reference for further optimization and application of prefabricated beam-column joints.

Biomass Chitosan-Induced Fe3O4 Functionalized Halloysite Nanotube Composites: Preparation, Characterization and Flame-Retardant Performance

Mengmeng Zhang,Yamin Cheng,Zhiwei Li,Xiaohong Li,Laigui Yu,Zhijun Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.15 No.01

An inorganic–organic nanohybrid flame retardant, HNT@CS@Fe3O4, is prepared by Halloysite nanotubes (HNT) as nanotemplate, chitosan (CS) as char-forming agent and ferroferric oxide (Fe3O4) playing in a catalytic role, aiming to endow enhanced flame-retardant performance of its nanohybrid. Results show that HNT@CS@Fe3O4 nanohybrids have a corn-like structure and can significantly improve the flame retardancy and thermal stability of epoxy resin (EP). Especially, the initial thermal degradation temperature of EP/HNT@CS@Fe3O4 is significantly improved by 24 ℃ relative to pure EP, and the residual carbon yield under air atmosphere is 8.8 wt.%, which is significantly higher than other EP composites, indicating a higher thermal stability is offered by the as-prepared nanohybrid. The limiting oxygen index of EP/10HNT@CS@Fe3O4 is 31.3%, which is 10.2% higher than that of pure EP. Meanwhile, the HNT@CS@Fe3O4 nanofiller reduces the peak heat release rate, CO production and peak smoke production release of EP nanocomposite by 32.0%, 44.0% and 33.0% in a cone calorimeter test, respectively. This is because the HNT-based composite can form a three-dimensional network structure into the EP matrix to inhibit heat release and diffusion of flammable moieties upon burning of EP. In the meantime, the incorporated Fe3O4 nanoparticle can in situ catalyze the charring of CS and EP matrix on the surface of HNT during the combustion process, which also contributes to the significantly increased fire safety of EP.

Preparation of Cobalt Ferrite Nanoparticle-Decorated Boron Nitride Nanosheet Flame Retardant and Its Flame Retardancy in Epoxy Resin

Qiaoran Zhang,Zhiwei Li,Xiaohong Li,Laigui Yu,Zhijun Zhang,Zhishen Wu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.5

Boron nitride nanosheet (BNNS) decorated with cobalt ferrite nanoparticle (CFN) to afford CFN-BNNS nanohybrid was prepared via a simple hydrothermal route and was well characterized. Subsequently, the as-prepared CFN-BNNS nanohybrid was incorporated into epoxy resin (EP) with the introduction of a weak rotary magnetic field to achieve order orientation, in order to reduce the fire risk and toxic hazards using enhanced shielding effect of BNNS upon combustion. Findings demonstrate that the CFN-BNNS nanohybrid is composed of CFN nanoparticle uniformly dispersed on BNNS surface. Thermal analysis and cone calorimeter data show that the CFN-BNNS nanofiller among EP matrix contributes to improving the char residues and mechanical properties of EP and reducing its fire risk as well as toxic hazards, especially the ordered one is advantageous over the disordered one in reducing the fire risk and toxic hazard. This is because, on the one hand, the orderly aligned BNNS as the physical barrier can more effectively prevent the transfer and diffusion of oxygen and heat. On the other hand, CFN can catalyze the degradation of EP to afford excessive chars on polymer surface; and it is also liable to decomposition during combustion, thereby generating ferrite species to promote EP degradation as well as cobalt species to enhance the oxidation of CO.

Influence of structure coupling effect on damping coefficient of offshore wind turbine blades

Jianping Zhang,Zhen Gong,Haolin Li,Mingqiang Wang,Zhiwei Zhang,Fengfeng Shi 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.6

The aim of this study was to explore the influence of structure coupling effect on structural damping of blade based on the blade vibration characteristic. For this purpose, the scaled blade model of NREL 5 MW offshore wind turbine was processed and employed in the wind tunnel test to validate the reliability of theoretical and numerical models. The attenuation curves of maximum displacement and the varying curves of equivalent damping coefficient of the blade under the rated condition were respectively compared and analyzed by constructing single blade model and whole machine model. The attenuation law of blade dynamic response was obtained and the structure coupling effect was proved to exert a significant influence on the equivalent damping coefficient. The results indicate that the attenuation trend of the maximum displacement response curve of the single blade varies more obviously with the increase of elastic modulus as compared to that under the structure coupling effect. In contrast to the single blade model, the varying curve of equivalent damping coefficient with the period is relatively steep for the whole machine model. The findings are of great significance to guide the structure design and material selection for wind turbine blades.

Dark Septate Endophyte (DSE) Fungi Isolated from Metal Polluted Soils: Their Taxonomic Position, Tolerance, and Accumulation of Heavy Metals In Vitro

Yujie Zhang,Yan Zhang,Maojun Liu,Xiaodong Shi,Zhiwei Zhao 한국미생물학회 2008 The journal of microbiology Vol.46 No.6

To understand the possible role of the plant root associated fungi on metal tolerance, their role in the uptake of heavy metals and the potential transfer of these metal ions to the plant, three strains of dark septate endophytic (DSE) fungi were isolated from a waste smelter site in southwest China, and one strain was isolated from a non-contaminated site. According to molecular phylogenetic analysis of the ITS 1-5.8S rDNA-ITS 2 gene regions and morphological characteristics, one is identified as Exophiala pisciphila, and the other three are non-sporulating fungi under the experiment condition with the nearest phylogenetic affinities to the Thysanorea papuana strain EU041814. Tolerance and accumulation abilities of the three DSE strains for metals were investigated in liquid culture. Minimum inhibitory concentrations (MIC) of Pb, Zn, and Cd were determined. It was demonstrated that the tolerance of the DSE strains varied between metal species and strains. The E. pisciphila strain is able to accumulate lead and cadmium over 20% and 5% of dry weight of biomass, respectively. Partial of the sequestrated metals can be washed with CaCl2. Morphological and enzyme activity changes taking place in the presence of excessive Pb, Cd, and/or Zn also indicate that the mechanism of heavy metal tolerance and accumulation of the DSE strains would be a complex process. The findings indicated promising tolerance and accumulation of the DSE strains with potential values in metal cycling and restoration of soil and water system.