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Temperature-Induced Unfolding Pathway of Staphylococcal Enterotoxin B:Insights from Circular Dichroism and Molecular Dynamics Simulation

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食品科学 2024年第18期45卷 55-76页

作者： LIU Ji ZHANG shiyu ZENG Yu DENG Yi Institute of Qinghai-Tibetan Plateau Southwest Minzu UniversityChengdu 610041China College of Food Sciences and Technology Southwest Minzu UniversityChengdu 610041China Wuliangye Group Co.Ltd. Yibin 644000China

In this study,circular dichroism(CD)and molecular dynamics(MD)simulation were used to investigate the thermal unfolding pathway of staphylococcal enterotoxin B(SEB)at temperatures of 298–371 and 298–500 K,and the relationship between the experimental and simulation results were *** computational findings on the secondary structure of SEB showed that at room temperature,the CD spectroscopic results were highly consistent with the MD ***,under heating conditions,the changing trends of helix,sheet and random coil obtained by CD spectral fitting were highly consistent with those obtained by *** order to gain a deeper understanding of the thermal stability mechanism of SEB,the MD trajectories were analyzed in terms of root mean square deviation(RMSD),secondary structure assignment(SSA),radius of gyration(R_(g)),free energy surfaces(FES),solvent-accessible surface area(SASA),hydrogen bonds and salt *** results showed that at low heating temperature,domain Ⅰ without loops(omitting the mobile loop region)mainly relied on hydrophobic interaction to maintain its thermal stability,whereas the thermal stability of domain Ⅱ was mainly controlled by salt bridges and hydrogen *** high heating temperature conditions,the hydrophobic interactions in domain Ⅰ without loops were destroyed and the secondary structure was almost completely lost,while domain Ⅱ could still rely on salt bridges as molecular staples to barely maintain the stability of the secondary *** results help us to understand the thermodynamic and kinetic mechanisms that maintain the thermal stability of SEB at the molecular level,and provide a direction for establishing safer and more effective food sterilization processes.

关键词： staphylococcal enterotoxin B circular dichroism molecular dynamics simulations temperature-induced unfolding

Experimental investigation on shear strength deterioration at the interface between different rock types under cyclic loading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3063-3079页

作者： Qiong Wu Zhiqi Liu Huiming Tang Liangqing Wang Xiaoxue Huo Zhen Cui shiyu Li Bo Zhang Zhiwei Lin Faculty of Engineering China University of GeosciencesWuhan430074China Guangxi Fangchenggang Beitou Environmental Protection Water Co. Ltd.Fangchenggang538021China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake;however,rare work has been devoted to this subject due to lack of *** this study,experimental investigations on shear strength weakening of discontinuities with different joint wall material(DDJM)under cyclic loading were conducted by taking the interface between siltstone and mudstone in the Shaba slope of Yunnan Province,China as research objects.A total of 99 pairs of similar material samples of DDJM(81 pairs)and discontinuities with identical joint wall material(DIJM)(18 pairs)were fabricated by inserting plates,engraved with typical surface morphology obtained by performing three-dimensional laser scanning on natural DDJMs sampled from field,into mold *** shear tests were conducted on these samples to study their shear strength changes with the cyclic number considering the effects of normal stress,joint surface morphology,shear displacement amplitude and shear *** results indicate that the shear stress *** displacement curves under each shear cycle and the peak shear strength *** number curves of the studied DDJMs are between those of DIJMs with siltstone and mudstone,while closer to those of DIJMs with *** peak shear strengths of DDJMs exhibit an initial rapid decline followed by a gradual decrease with the cyclic number and the decrease rate varies from 6%to 55.9%for samples with varied surface morphology under different testing *** normal stress,joint surface morphology,shear displacement amplitude and shear rate collectively influence the shear strength deterioration of DDJM under cyclic shear loading,with the degree of influence being greater for larger normal stress,rougher surface morphology,larger shear displacement amplitude and faster shear rate.

关键词： Discontinuities with different joint wall material(DDJM) Discontinuities with identical joint wall material(DIJM) Cyclic shear test Shear strength deterioration Joint surface morphology Shear displacement amplitude Shear rate Normal stress

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新疆吐鲁番胜金店墓地人骨的牙齿微磨耗

人类学学报 2022年第2期41卷 218-225页

作者：杨诗雨张群王龙张全超吉林大学生物考古实验室吉林大学考古学院长春130012 厦门大学人类学研究所厦门361005 吐鲁番学研究院吐鲁番838000

本文使用不同倍率的超景深电子显微镜,对新疆吐鲁番胜金店墓地中出土的13例臼齿的颊侧微磨耗形态进行了观察和研究。通过对臼齿颊侧表面凹坑和条痕形态微磨耗的测量和统计,计算出每例牙齿的微痕数量、均长、均宽、凹坑百分比和L_(h)/L_... 详细信息

本文使用不同倍率的超景深电子显微镜,对新疆吐鲁番胜金店墓地中出土的13例臼齿的颊侧微磨耗形态进行了观察和研究。通过对臼齿颊侧表面凹坑和条痕形态微磨耗的测量和统计,计算出每例牙齿的微痕数量、均长、均宽、凹坑百分比和L_(h)/L_(v)比值,按照性别和年龄分组进行人群内的数据对比分析。研究结果表明,该人群中年龄较大的个体摄入更高比例的植物类食物;两性的食物结构不存在显著性差异,男性摄入植物类食物比例略高,女性的食物结构在不同的年龄阶段有所差异。将胜金店墓地人群与不同生计方式人群的L_(h)/L_(v)比值进行人群间的差异性分析,并结合胜金店墓地的随葬品特点推测,胜金店墓地人群的食物结构以肉类食物为主,其生计模式以游牧业为主,兼营种植类经济。

关键词：胜金店墓地牙齿微磨耗电子显微镜食性分析

Two-step continuous flow process of sodium tanshinone ⅡA sulfonate using a 3D circular cyclone-type microreactor

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Chinese Chemical Letters 2024年第1期35卷 290-294页

作者： Maolin Sun Chaoming Liang Liming Cao Yaguo Wang Jiasheng yang shiyu Hou Wei Yu Yueyue Ma Ruihua Cheng Jinxing Ye School of Biomedical and Pharmaceutical Sciences Guangdong University of TechnologyGuangzhou 510006China School of Pharmacy East China University of Science and TechnologyShanghai 200237China School of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Shanghai No.1 Biochemical&Pharmaceutical Co. Ltd.Shanghai 200080China

A sustainable and practical process is presented for the direct synthesis of sodium tanshinone IIA sulfonate(STS).Our approach was inspired by the well-established and industrially applied batch synthetic route for STS *** constructed a telescoped two-step continuous flow *** involved a continuous tanshinone IIA sulfonation and in-line salt *** the setup,we constructed a 3D circular cyclone-type microreactor using femtosecond laser *** to the 68%yield for 2 h in batch,the two-step continuous flow had an STS yield of 90%,achieved for a total residence time of<3.0 min under optimal *** proposed continuous flow method vastly simplified the operation and improved procedural safety,while significantly reducing the required acid content and wastewater production.

关键词： Continuous flow Sodium tanshinone IIA sulfonate Cardiovascular Microreactor Green chemistry

Establishment of microneurovascular units in alginate hydrogel microspheres to reveal the anti-hypoxic effect of salidroside

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Journal of Pharmaceutical Analysis 2024年第6期14卷 926-929页

作者： shiyu Chen Yuxuan Li Yingrui Zhang Hongren Yao Tong Xu Yi Zhang Jin-Ming Lin Xian-Li Meng State Key Laboratory of Southwestern Chinese Medicine Resources Innovative Institute of Chinese Medicine and PharmacyChengdu University of Traditional Chinese MedicineChengdu611137China Beijing Key Laboratory of Microanalytical Methods and Instrumentation Department of ChemistryKey Laboratory of Bioorganic Phosphorus Chemistry&Chemical Biology(Ministry of Education)Tsinghua UniversityBeijing100084China School of Ethnic Medicine Chengdu University of Traditional Chinese MedicineChengdu611137China

Microneurovascular units(mNVUs),comprising neurons,micro-glia,and blood-brain barrier(BBB)endothelial cells,are pivotal to the central nervous system and are associated with cerebral hypoxia and brain *** hypoxia triggers microglial overactivity,causing inflammation,neuronal injury,and disruption of the BBB[1].Salidroside(Sal),a key compound in Tibetan medicine Rhodiola crenulata,mitigates hypoxia-induced metabolic disorders and neuronal damage by preserving mitochondrial function[2].

关键词： injuries preserving Tibetan

Design of artificial biomimetic channels with Na+permeation rate and selectivity potentially outperforming the natural sodium channel

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Nano Research 2024年第9期17卷 8638-8646页

作者： Zhi Zhu Yan Zhao Chao Chang Shaojian Yan Tingyu Sun shiyu Gu yangmei Li Dengsong Zhang Chunlei Wang Xiao Cheng Zeng School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai 200093China Innovation Laboratory of Terahertz Biophysics National Innovation Institute of Defense TechnologyBeijing 100071China School of Physics Peking UniversityBeijing 100871China International Joint Laboratory of Catalytic Chemistry College of SciencesShanghai UniversityShanghai 200444China Department of Materials Science and Engineering City University of Hong KongHong Kong 999077China

Artificial ion channels that enable high-efficiency ion transport have important implications in nanofluidics and biomedical applications such as drug ***,we show a simulation-based chemical design of a biomimetic sodium channel that possesses permeation rate and selectivity potentially higher than those of the state-of-the-art natural vertebrate voltage-gated sodium ***,our theoretical findings have undergone empirical testing,aligning well with the Arrhenius law as derived from a diverse range of experimental *** high-efficiency ion transport is achieved by anchoring the carboxylate functional groups within the channel filter.A key chemical guiding principle underlying the ion channel design is that the free-energy barrier for the Na+passage across the channel should be comparable to typical thermal energy at room *** the implementation of the chemical design,we found that the relatively low free-energy barrier can be attributed to the compensation effect of the carboxylate groups to the partially lost oxygen shell of the ion within the ion channel,as well as to the consonant vibration of the ions inside and outside the *** mechanistic understanding brings new insight,at the molecular level,into the high-efficiency ion transport across the designed membrane *** proof of principle achieved from the simulations will stimulate future experimental confirmation and potential applications of the high-performance artificial channels in nanofluidics and in bioinspired iontronics.

关键词： sodium channels anchoring carboxylate functional groups molecular dynamics simulations low free-energy barrier for ion passage thermal kinetic energy

卤胺化合物改性聚氨酯纳米纤维膜的结构与抗菌性能

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印染 2023年第7期49卷 1-6页

作者：杨世玉阎克路王维明东华大学化学与化工学院上海201620 国家染整工程技术研究中心上海201620 绍兴文理学院纺织服装学院浙江绍兴312000

采用2-羟甲基-5,5-二甲基乙内酰脲(MDMH)对聚氨酯预聚体进行改性,通过静电纺制备了纳米纤维膜,并对薄膜结构与抗菌性能进行了分析。结果表明:MDMH以接枝和物理共混两种形式存在于聚氨酯纳米纤维膜中;纺丝液固含量对聚氨酯静电纺可纺性... 详细信息

采用2-羟甲基-5,5-二甲基乙内酰脲(MDMH)对聚氨酯预聚体进行改性,通过静电纺制备了纳米纤维膜,并对薄膜结构与抗菌性能进行了分析。结果表明:MDMH以接枝和物理共混两种形式存在于聚氨酯纳米纤维膜中;纺丝液固含量对聚氨酯静电纺可纺性及纳米纤维膜表面形貌结构具有显著影响;氯化处理的MDMH改性聚氨酯纳米纤维膜对金黄葡萄球菌和大肠埃希菌都具有良好的抑制作用,且具有较好的耐洗涤性。MDMH改性会使聚氨酯软段熔融温度升高、硬段熔融温度降低,软段和硬段两相熔融焓均随着MDMH添加量的增加先增大后减小。MDMH的改性可改善聚氨酯中软段结晶性能。

关键词：纳米纤维膜静电纺抗菌卤胺聚氨酯

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单组分地聚物砂浆的力学性能和微观结构分析

西南交通大学学报 2021年第1期56卷 101-107,137页

作者：杨世玉赵人达靳贺松李福海乔瑜西南交通大学土木工程学院四川成都610031

为了研究不同NaOH浓度、胶砂比及溶胶比在多种固化温度下粉煤灰地聚物砂浆的强度发展规律及其微观机理,进行了力学性能试验,并用扫描电镜(SEM)和压汞试验(MIP)分析了其微观形貌、孔径分布.分析结果表明:对浓度为10%的NaOH溶液制备的地... 详细信息

为了研究不同NaOH浓度、胶砂比及溶胶比在多种固化温度下粉煤灰地聚物砂浆的强度发展规律及其微观机理,进行了力学性能试验,并用扫描电镜(SEM)和压汞试验(MIP)分析了其微观形貌、孔径分布.分析结果表明:对浓度为10%的NaOH溶液制备的地聚物砂浆试件,即使在很高的温度下固化也没有观察到明显的强度发展;随着NaOH浓度增加或固化温度上升,单组分地聚物砂浆的抗压和抗弯强度均可获得最佳值,该值出现位置由热固化温度和NaOH浓度的共同决定;地聚物的孔径分布微分曲线为单峰分布,控制NaOH的浓度可以大幅减小孔径微分曲线的峰值,显著降低地聚物的孔隙率;粉煤灰颗粒在NaOH的作用下逐渐溶解,并在其表面形成胶凝物质,当Na^+浓度较低时,地聚物较少,通过控制NaOH浓度可以使得地聚物变得密实,提高其抗压强度;基于热力学关系的分形模型描述地聚物孔结构形态的效果最好,其次为孔轴线模型,空间填充模型和海绵体模型只能较好地描述胶凝孔隙和过渡孔隙的孔结构分形维数;基于热力学关系与基于海绵模型分形维数计算值均在2.0~3.0之间,与一般水泥基材料的结果相近;适当调整NaOH的浓度可以改善地聚物的孔隙结构.

关键词：粉煤灰地质聚合物抗压强度压汞法(MIP) 扫描电镜(SEM)

BMP9 induces osteogenic differentiation through up-regulating LGR4 via the mTORC1/ Stat3 pathway in mesenchymal stem cells

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Genes & Diseases 2024年第3期11卷 468-483页

作者： Jie Zhang Jinhai Jiang Hang Liu shiyu Wang Kaixin Ke Siyuan Liu Yue Jiang Lu Liu Xiang Gao Baicheng He Yuxi Su Department of Pharmacology School of PharmacyChongqing Medical UniversityChongqing 400016China Key Laboratory of Biochemistry and Molecular Pharmacology of Chongqing Chongqing Medical UniversityChongqing 400016China Department of Orthopedics Second Affiliated Hospital of Chongqing Medical UniversityChongqing 400016China orthopedics Department Children's Hospital of Chongqing Medical UniversityChongqing 400014China China International Science and Technology Cooperation Base of Child Development and Critical Disorders Jiangxi Hospital Affiliated Children's Hospital of Chongqing Medical UniversityJiangxi 330000China National Clinical Research Center for Child Health and Disorders China

Bone defects and non-union are prevalent in clinical orthopedy,and the outcomes of current treatments are often *** tissue engineering offers a promising approach to treating these conditions *** morphogenetic protein 9(BMP9)can commit mesenchymal stem cells to osteogenic lineage,and a knowledge of the underlying mechanisms may help advance the field of bone tissue ***-rich repeats con-taining G protein-coupled receptor 4(LGR4),a member of G protein-coupled receptors,is essential for modulating bone *** study is aimed at investigating the impact of LGR4 on BMP9-induced osteogenesis in mesenchymal stem cells as well as the underlying *** marrow stromal cells from BMp9-knockout mice exhibited diminished LGR4 expression,and exogenous LGR4 clearly restored the impaired osteogenic potency of the bone marrow stromal ***,LGR4 expression was increased by BMP9 in C3H10T1/2 ***4 augmented the benefits of BMP9-induced osteogenic markers and bone formation,whereas LGR4 inhibition restricted these ***,the BMP9-induced li-pogenic markers were increased by LGR4 *** protein levels of Raptor and p-Stat3 were elevated by *** knockdown or p-Stat3 suppression attenuated the osteoblastic markers and LGR4 expression brought on by ***4 significantly reversed the blocking ef-fect of Raptor knockdown or p-Stat3 suppression on the BMP9-induced osteoblastic *** interacts with p-Stat3,and p-Stat3 activates the LGR4 promoter *** conclusion,LGR4 boosts BMP9 osteoblastic potency in mesenchymal stem cells,and BMP9 may up-regulate LGR4 via the mTORC1/Stat3 signal activation.

关键词： BMP9 LGR4 mTORC1 Osteogenic differentiation Stat3