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Multiscale structure and function of the aortic valve apparatus

PHYSIOLOGICAL REVIEWS 2024年第4期104卷 1487-1532页

作者： El-Nashar, Hussam Sabry, Malak Tseng, Yuan-Tsan Francis, Nadine Latif, Najma Parker, Kim H. Moore Jr, James E. Yacoub, Magdi H. Magdi Yacoub Fdn Aswan Heart Res Ctr Cairo Egypt Imperial Coll London Dept Bioengn London England Kings Coll London Dept Biomed Engn London England Magdi Yacoub Inst Heart Sci Ctr London England Imperial Coll London Natl Heart & Lung Inst London England

Whereas studying the aortic valve in isolation has facilitated the development of life-saving procedures and technologies, the dynamic interplay of the aortic valve and its surrounding structures is vital to preserving their function across the wide range of conditions encountered in an active lifestyle. Our view is that these structures should be viewed as an integrated functional unit, here referred to as the aortic valve apparatus (AVA). The coupling of the aortic valve and root, left ventricular outflow tract, and blood circulation is crucial for AVA's functions: unidirectional flow out of the left ventricle, coronary perfusion, reservoir function, and support of left ventricular function. In this review, we explore the multiscale biological and physical phenomena that underlie the simultaneous fulfillment of these functions. A brief overview of the tools used to investigate the AVA, such as medical imaging modalities, experimental methods, and computational modeling, specifically fluid-structure interaction (FSI) simulations, is included. Some pathologies affecting the AVA are explored, and insights are provided on treatments and interventions that aim to maintain quality of life. The concepts explained in this article support the idea of AVA being an integrated functional unit and help identify unanswered research questions. Incorporating phenomena through the molecular, micro, meso, and whole tissue scales is crucial for understanding the sophisticated normal functions and diseases of the AVA.

关键词： aortic root aortic valve biomechanics molecular, developmental and cellular mechanisms structure-function relationships

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structure-function relationships of autotaxin, a secreted lysophospholipase D

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Advances in Biological Regulation 2013年第1期53卷 112-117页

作者： Hausmann, Jens Perrakis, Anastassis Moolenaar, Wouter H. Division of Biochemistry The Netherlands Cancer Institute 1066CX Amsterdam Netherlands Division of Cell Biology The Netherlands Cancer Institute 1066CX Amsterdam Netherlands

Autotaxin (ATX or ENPP2) is an ectonucleotide pyrophosphatase/phosphodiesterase (ENPP) that functions as a secreted lysophospholipase D to produce the multifunctional lipid mediator lysophosphatidic acid (LPA) from more complex lysophospholipids. LPA acts on distinct G protein-coupled receptors thereby activating multiple signaling cascades and cellular responses. The ATX-LPA signaling axis is implicated in a remarkably wide variety of physiological and pathological processes, ranging from vascular and neural development to lymphocyte homing, fibrosis and cancer. Despite much progress in understanding LPA receptor signaling, the precise mode of action of ATX has long remained elusive due to the lack of structural data. In particular, it has been unclear what makes ATX a unique lysophospholipase D and how the enzyme is targeted to LPA-responsive cells. Recent structural studies have begun to clarify these issues. Here we discuss new insights and inferences from the ATX structure. © 2012 Elsevier Ltd.

关键词： Lysophospholipase Lipoprotein(a) structure-function relationships ATX Neurogenesis ENPP2 gene Pathologic Processes Platelet Activating Factor alkylglycerophosphoethanolamine phosphodiesterase mechanism of action

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Heme-based Oxygen Sensors: structure-function relationships

Heme-based Oxygen Sensors: Structure-function Relationships

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2014第五届国际工业酶与生物催化大会

作者： Toru Shimizu Shantou University Medical College

Heme proteins play important roles in O2 storage(myoglobin), O2 transfer(hemoglobin), O2 activation(cytochrome P450), electron transfer(cytochromes), and many more functions. In addition to these well-known prototypical heme proteins, is an emerging class of heme-based oxygen sensors. In general, the heme-based oxygen sensor is composed of two domains: an N-terminal sensor domain and a C-terminal functional domain. The heme iron complex bound to the sensor domain acts as the O2 sensor. Association of the O2 molecule to the heme iron complex or dissociation from it alters the protein structure in the heme-bound sensor domain. In this process, binding of the O2 molecule is the first signal and the protein structural alteration near the heme-bound site becomes the second signal. This second signal is then transduced to the C-terminal functional domain, switching on(or off) the associated activity, which may consist of phosphodiesterase(PDE), diguanylate cyclase(DGC), histidine kinase(HK), and methyl-accepting chemotaxis. Our group has been studying the structure and function relationships of representative oxygen sensors such as Ec DOS, YddV and AfGcHK that are involved in PDE, DGC and HK reactions, respectively. Interestingly,catalytic activities of those oxygen sensors are regulated by NO and CO. Furthermore, enhancement of the PDE activity of Ec DOS by H2 S is novel to be noted. I discuss the molecular mechanism of the roles of the heme iron complex and the gaseous molecule in the catalytic regulation of those oxygen sensors.

关键词： Heme-based Oxygen Sensors structure-function relationships

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Ion type-based formation rules and functional properties of polysaccharide-starch aerogels with chitooligosaccharide, xanthan gum, and locust bean gum: A comparative study

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FOOD RESEARCH INTERNATIONAL 2025年 202卷 115674页

作者： Lin, Qian Zhao, Wenqing Liang, Wei Wang, Xinyu Zeng, Jie Gao, Haiyan Li, Wenhao Northwest A&F Univ Coll Food Sci & Engn Yangling 712100 Shaanxi Peoples R China Henan Inst Sci & Technol Sch Food Sci Xinxiang 453003 Henan Peoples R China

Polysaccharide ion types may play a regulatory role in the functionalization development of starchpolysaccharide-based gels, although the relevant mechanisms remain to be elucidated. This study provides a simple and effective strategy for developing gels suitable for different adsorption scenarios by adding different ratios and ion types of polysaccharides. The addition of locust bean gum (LBG, neutral charge) and xanthan gum (XG, -/negative charge) increased the viscosity of wheat gels, with XG increasing more significantly at the same addition. Meanwhile, chito oligosaccharides (COS, +/positive charge) decreased the viscosity of wheat gels. SEM showed that the gels' pore size became larger after adding polysaccharides. FT-IR results showed that adding all three polysaccharides resulted in a more disordered structure and a decrease in the hardness of the gels. However, due to the different charges, the adsorption property results showed that adding the anionic polysaccharide XG increased the methylene blue adsorption capacity dramatically, while COS showed the opposite trend. The obtained results are expected to facilitate the high-value processing and utilization of polysaccharide resources and the on-demand construction of gel materials with promising textural or adsorption performance in food processing or industrial manufacture.

关键词： Different ionic polysaccharides Starch-polysaccharide composite gels Interaction mechanism structure-function relationships

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From Molecules to Products: Some Aspects of structure-function relationships in Cereal Starches

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CEREAL CHEMISTRY 2013年第4期90卷 326-334页

作者： Eliasson, Ann-Charlotte Bergenstahl, Bjorn Nilsson, Lars Sjoo, Malin Lund Univ Dept Food Technol Engn & Nutr S-22100 Lund Sweden

In this review, starch behavior is described from molecules in solution to the use of starch in products. The determination of molecular characteristics with asymmetrical flow field-flow fractionation is described, and the behavior of starch in binary solutions is discussed. The organization of starch in granules and the changes in organization during gelatinization and retrogradation are then described. The role of starch retrogradation in bread staling is described in some detail, and the influence of water mobility and distribution is discussed in relation to amylopectin retrogradation. Finally, the use of starch as emulsifier is described. Hydrophobically modified starch is one possibility for emulsion stabilization;also, the starch granule as such can be used to stabilize emulsions (so-called Pickering emulsions).

关键词： Organizations Starch granules Emulsions structure-function relationships molecules starch Emulsifying Agents retrogradation gelatinization gelation

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Linking xylem structure and function: the comparative method in from the cold

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NEW PHYTOLOGIST 2022年第3期235卷 815-820页

作者： Olson, Mark E. Univ Nacl Autonoma Mexico Inst Biol Tercer Circuito SnCiudad Univ Mexico City 04510 DF Mexico

The field of functional xylem biology aims to understand how xylem structure gives rise to xylem function. This effort requires understanding processes at very tiny scales, from nanometric-level variation in the intricacies of pit membrane structure (Li et al., 2016;Kaack et al., 2021) to the intermolecular interactions involved in the formation of gas bubbles in xylem sap (Schenk et al., 2015, 2017). It requires understanding how these very smalllevel events give rise to whole-plant properties, such as bulk water flow through the xylem or whole-plant transpiration and carbon (C) capture (Tyree & Ewers, 1991;Comstock & Sperry, 2000;Enquist et al., 2007). It is necessary to understand how some individuals within populations in the distant past survived and reproduced better than their conspecifics all because of certain structure-function relations manifest at these different scales (Carlquist, 1975). This understanding extends to estimating forest productivity at a landscape level, modeling `average' plant structure, or predicting which trees will die across a drought-stricken landscape (West et al., 1999;Christoffersen et al., 2016;Trugman et al., 2021). Given the size of the task facing the field, the toolbox of xylem functional biology is a very large one indeed. The recent study published in this issue of New Phytologist by Savage et al. (2022;pp. 953-964) is a model of how this toolbox can, and must, seamlessly integrate data and theory from across levels, from the very small scale of processes within xylem conduits to the millionsplus years scale of evolutionary time. Before highlighting just some of the inferential richness in Savage et al. (2022), let me first explore why the integration of levels is such a challenge, and the empirical turn that this challenge demands.

关键词： cold tolerance evolution freezing-induced embolism leaf phenology north-temperate forests structure-function relationships xylem

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High spatiotemporal resolution transmission electron microscopy and diffraction: Progress from subnanosecond laser-induced structural dynamics to femtosecond quantum tomography

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NANO TODAY 2025年 61卷

作者： Aseyev, Sergei A. Mironov, Boris N. Poydashev, Denis G. Ryabov, Evgeny A. Miller, R. J. Dwayne Li, Zheng Zhang, Ming Ischenko, Anatoly A. RAS Inst Spect Fizicheskaya St 5 Moscow 108840 Russia Univ Toronto Dept Chem Toronto ON M5S 3H6 Canada Univ Toronto Dept Phys Toronto ON M5S 3H6 Canada Peking Univ State Key Lab Mesoscop Phys Beijing 100871 Peoples R China Peking Univ Collaborat Innovat Ctr Quantum Matter Sch Phys Beijing 100871 Peoples R China Shanxi Univ Collaborat Innovat Ctr Extreme Opt Taiyuan 030006 Shanxi Peoples R China Peking Univ Yangtze Delta Inst Optoelect Nantong 226010 Jiangsu Peoples R China MIREA Russian Technol Univ Inst Fine Chem Technol Dept Analyt Chem Vernadsky Ave 86 Moscow 119571 Russia

The use of short photoelectron pulses, pioneered in the 1980s, opened up the possibility of studying structural dynamics with high spatiotemporal resolution. The combination of nano-pico-femtosecond lasers with electron- based technology has become extremely fruitful for observing the behavior of atoms and molecules on their natural length and time scales. In imaging mode, this concept soon led to the creation of 4D transmission electron microscopy. In the electron diffraction mode, the achievement of ultrabright electron sources provided a unique opportunity to shoot molecular movies with atomic resolution. These sources are at their fundamental space charge limit with sufficient brightness to literally light up atomic motions. The high sensitivity of this approach, combined with low radiation damage, made it possible to atomically resolve reaction dynamics with nanograms of material. In contrast to the X-ray free electron lasers (XFELs), the development of ultrabright electron sources made it possible to conduct experiments on very thin films of promising materials in small-scale facilities in standard laboratories. The extension to quantum tomography has recently opened a new page in the study of matter using short electron bunches. Here we review the development of ultrafast transmission electron microscopy and diffraction techniques that enable detection of structural dynamics on the primary timescales.

关键词： Ultrafast transmission electron microscopy Simultaneous real space imaging Structural dynamics structure-function relationships Ultrafast laser-induced processes Transition state crossing Femtosecond quantum tomography

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Defects in Inorganic Mechanoluminescent Phosphors: Insights and Impacts

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ADVANCED functionAL MATERIALS 2025年

作者： Li, Wenhao Wu, Sheng Ren, Jing Xiong, Puxian Harbin Engn Univ Coll Phys & Optoelect Engn Key Lab Photon Mat & Devices Phys Ocean Applicat Minist Ind & Informat Technol China Harbin 150001 Peoples R China South China Normal Univ Guangdong Basic Res Ctr Excellence Struct & Fundam Sch Phys Guangdong Prov Key Lab Quantum Engn & Quantum Mat Guangzhou 510006 Peoples R China Univ Hong Kong Dept Elect & Elect Engn Hong Kong 999077 Peoples R China

Mechanoluminescence (ML), the light emission of materials in response to mechanical stimuli, has gained significant attention in various fields due to the in situ and real-time "force to light" converting ability. Defects dominate the ML process, either for accommodating carriers or as sites for carrier recombination. However, comprehensive discussions on ML-based defects are rarely reported. The review opens with an exploration of recent progress in ML research, highlighting the central role of defects in ML. A range of defect types commonly exist in ML materials are firstly introduced, which aims to highlight the profound influences on ML. Subsequently reported defect-dominated phosphors are researched to elucidate the intricate relationship between specific defect types and their influence on ML performance, shedding light on the underlying luminescence mechanisms. Afterward, experimental techniques for defect characterization are also researched to demonstrate how defects work in ML. The role of computational modeling is confirmed to act as a powerful tool for investigating the atomistic mechanisms of defect-related processes and enabling precise control of defects in ML materials. In conclusion, this mini-review underscores the centrality of defects in ML materials, offering an integrated perspective on their profound influence and potential to guide future research endeavors.

关键词： charge carrier defect inorganic luminescence mechanoluminescence structure-function relationships

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The dynamic view of proteins Comment on "Comparing proteins to their internal dynamics: Exploring structure-function relationships beyond static structural alignments"

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PHYSICS OF LIFE REVIEWS 2013年第1期10卷 29-30页

作者： Orozco, Modesto Inst Res Biomed Barcelona Joint IRB BSC Program Computat Biol Barcelona 08028 Spain Univ Barcelona Fac Biol Dept Biochem E-08028 Barcelona Spain

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Deciphering the interplay between pectin structural variability, intestinal bioavailability and gut microbiota metabolism: A review

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CARBOHYDRATE POLYMERS 2025年 360卷 123596页

作者： Zhao, Yuanyuan Aru, Violetta Wang, Dan Wang, Pan Qin, Peiyou Jiang, Qianqian Li, Zudi Engelsen, Soren Balling Zhao, Xiaoyan Beijing Acad Agr & Forestry Sci Inst Agrifood Proc & Nutr Beijing Key Lab Agr Prod Fruits & Vegetables Prese Key Lab Vegetable Postharvest ProcMinist Agr & Ru Beijing 100097 Peoples R China Univ Copenhagen Dept Food Sci DK-1958 Frederiksberg C Denmark

Pectins are parts of fruits, vegetables and other plant-based foods in the human daily diet. They are resilient to gastric digestion but undergo fermentation primarily in the large intestine, peaking in the cecum. The depolymerization of the pectins induced by the gut microbiota generally facilitates the subsequent fermentation of sugar monomers, during which SCFAs are primarily generated to exert multiple beneficial functions. Given structural heterogeneity of pectins and intricate process of microbial metabolism, it is crucial to elucidate how the multi-scale structure of pectins impacts their gut fermentation behavior. This review delves into distinct structural domains and fine structural characteristics of pectins, describes their degradation mechanism and bioavailability in the gastrointestinal tract, and provides an overview of the associated pectinolytic enzymes, gut microbiota community, and microbial metabolites. Moreover, recent advances are summarized in the relationships between gut fermentability and various structural parameters of pectins, including molecular size, esterification degree, monosaccharides composition and molecular conformation. Furthermore, how the structural complexity of pectins influences the interplay between saccharolytic metabolism and proteolytic metabolism during microbial fermentation is proposed. This work would help to unravel the "pectin structure-gut micro-biota-host health" interactions, thereby guiding the design of functional foods targeting specific microorganisms in future personalized diets.

关键词： Pectin Structural characteristics Fecal fermentation Gut microbiota Metabolic pathway structure-function relationships

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