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https://www.readbyqxmd.com/read/28317948/local-remodeling-of-synthetic-extracellular-matrix-microenvironments-by-co-cultured-endometrial-epithelial-and-stromal-cells-enables-long-term-dynamic-physiological-function
#1
Christi D Cook, Abby S Hill, Margaret Guo, Linda Stockdale, Julia P Papps, Keith B Isaacson, Douglas A Lauffenburger, Linda G Griffith
Mucosal barrier tissues, comprising a layer of tightly-bonded epithelial cells in intimate molecular communication with an underlying matrix-rich stroma containing fibroblasts and immune cells, are prominent targets for drugs against infection, chronic inflammation, and other disease processes. Although human in vitro models of such barriers are needed for mechanistic studies and drug development, differences in extracellular matrix (ECM) needs of epithelial and stromal cells hinder efforts to create such models...
March 20, 2017: Integrative Biology: Quantitative Biosciences From Nano to Macro
https://www.readbyqxmd.com/read/28315735/very-rapid-amyloid-fibril-formation-by-a-bacterial-lipase-in-the-absence-of-a-detectable-lag-phase
#2
Fatemeh Rashno, Khosro Khajeh, Claudia Capitini, Reza H Sajedi, Maryam Monsef Shokri, Fabrizio Chiti
The conversion of proteins from their soluble states into well-organized amyloid fibrils has received abundant attention. This process typically consists of three stages: lag, growth and plateau phases. In this study, the process of amyloid fibril formation by lipase from Pseudomonas sp. after diluting out urea was examined by Thioflavin T (ThT) fluorescence, Congo red (CR) binding, 8-anilinonaphthalene-1-sulfonic acid (ANS) binding, dynamic light scattering (DLS), circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopies, X-ray diffraction (XRD) and transmission electron microscopy (TEM)...
March 15, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28315381/alfa-helix-to-beta-sheet-transition-in-long-chain-poly-l-lysine-formation-of-alfa-helical-fibrils-by-poly-l-lysine
#3
Katarzyna Cieślik-Boczula
The temperature-induced α-helix to β-sheet transition in long-chain poly-l-lysine (PLL), accompanied by the gauche-to-trans isomerization of CH2 groups in the hydrocarbon side chains of Lys amino acid residues, and formation of β-sheet as well as α-helix fibrillar aggregates of PLL have been studied using Fourier-transform infrared (FT-IR) and vibrational circular dichroism (VCD) spectroscopy, and transmission electron microscopy (TEM). In a low-temperature alkaline water solution or in a methanol-rich water mixture, the secondary structure of PLL is represented by α-helical conformations with unordered and gauche-rich hydrocarbon side chains...
March 14, 2017: Biochimie
https://www.readbyqxmd.com/read/28306225/the-ehlers-danlos-syndromes-rare-types
#4
REVIEW
Angela F Brady, Serwet Demirdas, Sylvie Fournel-Gigleux, Neeti Ghali, Cecilia Giunta, Ines Kapferer-Seebacher, Tomoki Kosho, Roberto Mendoza-Londono, Michael F Pope, Marianne Rohrbach, Tim Van Damme, Anthony Vandersteen, Caroline van Mourik, Nicol Voermans, Johannes Zschocke, Fransiska Malfait
The Ehlers-Danlos syndromes comprise a clinically and genetically heterogeneous group of heritable connective tissue disorders, which are characterized by joint hypermobility, skin hyperextensibility, and tissue friability. In the Villefranche Nosology, six subtypes were recognized: The classical, hypermobile, vascular, kyphoscoliotic, arthrochalasis, and dermatosparaxis subtypes of EDS. Except for the hypermobile subtype, defects had been identified in fibrillar collagens or in collagen-modifying enzymes. Since 1997, a whole spectrum of novel, clinically overlapping, rare EDS-variants have been delineated and genetic defects have been identified in an array of other extracellular matrix genes...
March 2017: American Journal of Medical Genetics. Part C, Seminars in Medical Genetics
https://www.readbyqxmd.com/read/28303942/signature-of-an-aggregation-prone-conformation-of-tau
#5
Neil A Eschmann, Elka R Georgieva, Pritam Ganguly, Peter P Borbat, Maxime D Rappaport, Yasar Akdogan, Jack H Freed, Joan-Emma Shea, Songi Han
The self-assembly of the microtubule associated tau protein into fibrillar cell inclusions is linked to a number of devastating neurodegenerative disorders collectively known as tauopathies. The mechanism by which tau self-assembles into pathological entities is a matter of much debate, largely due to the lack of direct experimental insights into the earliest stages of aggregation. We present pulsed double electron-electron resonance measurements of two key fibril-forming regions of tau, PHF6 and PHF6*, in transient as aggregation happens...
March 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28301805/the-protective-role-of-plant-biophenols-in-mechanisms-of-alzheimer-s-disease
#6
REVIEW
Syed H Omar, Christopher J Scott, Adam S Hamlin, Hassan K Obied
Self-assembly of amyloid beta peptide (Aβ) into the neurotoxic oligomers followed by fibrillar aggregates is a defining characteristic of Alzheimer's disease (AD). Several lines of proposed hypotheses have suggested the mechanism of AD pathology, though the exact pathophysiological mechanism is not yet elucidated. The poor understanding of AD and multitude of adverse responses reported from the current synthetic drugs are the leading cause of failure in the drug development to treat or halt the progression of AD and mandate the search for safer and more efficient alternatives...
March 3, 2017: Journal of Nutritional Biochemistry
https://www.readbyqxmd.com/read/28295701/the-impact-of-binding-of-macrocyclic-metal-complexes-on-amyloid-fibrillization-of-insulin-and-lysozyme
#7
Vladyslava Kovalska, Svitlana Chernii, Vsevolod Cherepanov, Mykhaylo Losytskyy, Victor Chernii, Oleg Varzatskii, Anton Naumovets, Sergiy Yarmoluk
Amyloid fibrils are insoluble protein aggregates whose accumulation in cells and tissues is connected with a range of pathological diseases. We studied the impact of 2 metal complexes (axially coordinated Hf phthalocyanine and iron (II) clathrochelate) on aggregation of insulin and lysozyme. For both proteins, the host-guest interaction with these compounds changes the kinetics of fibrillization and affects the morphology of final aggregates. The Hf phthalocyanine is a very efficient inhibitor of insulin fibrillization; in its presence, only very low amounts of fibrils with the diameters of 0...
March 14, 2017: Journal of Molecular Recognition: JMR
https://www.readbyqxmd.com/read/28292187/distinct-mechanisms-determine-%C3%AE-synuclein-fibril-morphology-during-growth-and-maturation
#8
Arshdeep Sidhu, Ine Segers-Nolten, Vincent Raussens, Mireille M A E Claessens, Vinod Subramaniam
Amyloid polymorphs have become one of the focal points of molecular studies of neurodegenerative diseases like Parkinson's disease. Due to their distinct biochemical properties and prion-like characteristics, insights into the molecular origin and stability of amyloid polymorphs over time are crucial for understanding the potential role of amyloid polymorphism in these diseases. Here, we systematically study the fibrillization of recombinantly produced human α-synuclein (αSyn) over an extended period of time to unravel the origin and temporal evolution of polymorphism...
March 15, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28292179/cross-linking-approaches-to-tuning-the-mechanical-properties-of-peptide-%C3%AF-electron-hydrogels
#9
Wathsala Liyanage, Herdeline Ann M Ardoña, Hai-Quan Mao, John D Tovar
Self-assembling peptides are extensively exploited as bioactive materials in applications such as regenerative medicine and drug delivery despite the fact that their relatively weak noncovalent interactions often render them susceptible to mechanical destruction and solvent erosion. Herein, we describe how covalent cross-linking enhances the mechanical stability of self-assembling π-conjugated peptide hydrogels. We designed short peptide-chromophore-peptide sequences displaying different reactive functional groups that can form cross-links with appropriately modified bifunctional polyethylene glycol (PEG)-based small guest molecules...
March 15, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28290684/polymer-peptide-conjugates-disassemble-amyloid-%C3%AE-fibrils-in-a-molecular-weight-dependent-manner
#10
Yang Song, Edwin G Moore, Yanshu Guo, Jeffrey S Moore
Amyloid aggregation and deposition are associated with many intractable human diseases. Although the inhibition of amyloid protein aggregation has been well-studied, the disaggregation and dissolution of existing amyloid fibrils is less known. Taking a fibrillar assembly of amyloid β (Aβ) peptide as the model system, here we report multivalent polymer-peptide conjugates (mPPCs) that disassemble preformed Aβ fibrils into dispersible sub-100 nm structures. Atomic force microscopy and dynamic light scattering studies show that the disassembly rate of preformed Aβ fibrils is controlled by the molecular weight of mPPCs...
March 14, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28289092/ampk-negatively-regulates-tensin-dependent-integrin-activity
#11
Maria Georgiadou, Johanna Lilja, Guillaume Jacquemet, Camilo Guzmán, Maria Rafaeva, Charlotte Alibert, Yan Yan, Pranshu Sahgal, Martina Lerche, Jean-Baptiste Manneville, Tomi P Mäkelä, Johanna Ivaska
Tight regulation of integrin activity is paramount for dynamic cellular functions such as cell matrix adhesion and mechanotransduction. Integrin activation is achieved through intracellular interactions at the integrin cytoplasmic tails and through integrin-ligand binding. In this study, we identify the metabolic sensor AMP-activated protein kinase (AMPK) as a β1-integrin inhibitor in fibroblasts. Loss of AMPK promotes β1-integrin activity, the formation of centrally located active β1-integrin- and tensin-rich mature fibrillar adhesions, and cell spreading...
March 13, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28287136/a-dual-pathogenic-mechanism-links-tau-acetylation-to-sporadic-tauopathy
#12
Hanna Trzeciakiewicz, Jui-Heng Tseng, Connor M Wander, Victoria Madden, Ashutosh Tripathy, Chao-Xing Yuan, Todd J Cohen
Tau acetylation has recently emerged as a dominant post-translational modification (PTM) in Alzheimer's disease (AD) and related tauopathies. Mass spectrometry studies indicate that tau acetylation sites cluster within the microtubule (MT)-binding region (MTBR), suggesting acetylation could regulate both normal and pathological tau functions. Here, we combined biochemical and cell-based approaches to uncover a dual pathogenic mechanism mediated by tau acetylation. We show that acetylation specifically at residues K280/K281 impairs tau-mediated MT stabilization, and enhances the formation of fibrillar tau aggregates, highlighting both loss and gain of tau function...
March 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28283460/anti-parkinsonian-l-dopa-can-also-act-as-anti-systemic-amyloidosis-a-mechanistic-exploration
#13
Saima Nusrat, Nida Zaidi, Mohammad Khursheed Siddiqi, Masihuz Zaman, Ibrar Ahmed Siddique, Mohammad Rehan Ajmal, Ali Saber Abdelhameed, Rizwan Hasan Khan
In spite of the fact that amyloid related neurodegenerative illnesses and non-neuropathic systemic amyloidosis have allured the research endeavors, as no cure has been announced yet apart from symptomatic treatment. Therapeutic agents which can reduce or disaggregate those toxic oligomers and fibrillar species have been studied with more compounds are on their way. The current research work describes comprehensive biophysical, computational and microscopic studies which reveal that L-3, 4-dihydroxyphenylalanine (L-Dopa) have indisputable efficacy to hinder the heat induced amyloid fibrillation of the human lysozyme (HL) and also preserve the fibril disaggregating potential...
March 7, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28282805/humanin-specifically-interacts-with-amyloid-%C3%AE-oligomers-and-counteracts-their-in-vivo-toxicity
#14
Margherita Romeo, Matteo Stravalaci, Marten Beeg, Alessandro Rossi, Fabio Fiordaliso, Alessandro Corbelli, Mario Salmona, Marco Gobbi, Alfredo Cagnotto, Luisa Diomede
The 24-residue peptide humanin (HN) has been proposed as peptide-based inhibitors able to interact directly with amyloid-β (Aβ) oligomers and interfere with the formation and/or biological properties of toxic Aβ species. When administered exogenously HN, or its synthetic S14G-derivative (HNG), exerted multiple cytoprotective effects, counteracting the Aβ-induced toxicity. Whether these peptides interact directly with Aβ, particularly with the soluble oligomeric assemblies, remains largely unknown. We here investigated the ability of HN and HNG to interact directly with highly aggregating Aβ42, and interfere with the formation and toxicity of its oligomers...
March 6, 2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28281925/infectious-prions-and-proteinopathies
#15
Rona M Barron
Transmissible spongiform encephalopathies (TSEs) are caused by an infectious agent that is thought to consist of only misfolded and aggregated prion protein (PrP). Unlike conventional micro-organisms, the agent spreads and propagates by binding to and converting normal host PrP into the abnormal conformer, increasing the infectious titre. Synthetic prions, composed of refolded fibrillar forms of recombinant PrP (rec-PrP) have been generated to address whether PrP aggregates alone are indeed infectious prions...
January 2, 2017: Prion
https://www.readbyqxmd.com/read/28281531/structural-basis-of-homo-and-heterotrimerization-of-collagen-i
#16
Urvashi Sharma, Loïc Carrique, Sandrine Vadon-Le Goff, Natacha Mariano, Rainier-Numa Georges, Frederic Delolme, Peppi Koivunen, Johanna Myllyharju, Catherine Moali, Nushin Aghajari, David J S Hulmes
Fibrillar collagen molecules are synthesized as precursors, procollagens, with large propeptide extensions. While a homotrimeric form (three α1 chains) has been reported in embryonic tissues as well as in diseases (cancer, fibrosis, genetic disorders), collagen type I usually occurs as a heterotrimer (two α1 chains and one α2 chain). Inside the cell, the role of the C-terminal propeptides is to gather together the correct combination of three α chains during molecular assembly, but how this occurs for different forms of the same collagen type is so far unknown...
March 10, 2017: Nature Communications
https://www.readbyqxmd.com/read/28274703/spines-of-the-porcupine-fish-structure-composition-and-mechanical-properties
#17
Frances Y Su, Eric A Bushong, Thomas J Deerinck, Kyungah Seo, Steven Herrera, Olivia A Graeve, David Kisailus, Vlado A Lubarda, Joanna McKittrick
This paper explores the structure, composition, and mechanical properties of porcupine fish spines for the first time. The spine was found to be composed of nanocrystalline hydroxyapatite, protein (collagen), and water using X-ray diffraction, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. Microstructures have mineralized fibrillar sheets in the longitudinal direction and in a radial orientation in the transverse direction that were observed using light and electron microscopy. Based on the images, the hierarchical structure of the spine shows both concentric and radial reinforcement...
February 28, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28270981/label-free-imaging-of-amyloids-using-their-intrinsic-linear-and-nonlinear-optical-properties
#18
Patrik K Johansson, Patrick Koelsch
The optical properties of amyloid fibers are often distinct from those of the source protein in its non-fibrillar form. These differences can be utilized for label-free imaging or characterization of such structures, which is particularly important for understanding amyloid fiber related diseases such as Alzheimer's and Parkinson's disease. We demonstrate that two amyloid forming proteins, insulin and β-lactoglobulin (β-LG), show intrinsic fluorescence with emission spectra that are dependent on the excitation wavelength...
February 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28270508/discoidin-domain-receptor-2-mediates-collagen-induced-activation-of-membrane-type-1-matrix-metalloproteinase-in-human-fibroblasts
#19
Iwona Majkowska, Yasuyuki Shitomi, Noriko Ito, Nathanael S Gray, Yoshifumi Itoh
Membrane-Type 1 Matrix Metalloproteinase (MT1-MMP) is a membrane-bound MMP that is highly expressed in cells with invading capacity including fibroblasts and invasive cancer cell. A potential physiological stimulus for MT1-MMP expression is fibrillar collagen, and it has been shown that it upregulates both MT1-MMP gene and functions in various cell types. However, the mechanisms of collagen-mediated MT1-MMP activation is not clearly understood. In this study we identified discoidin domain receptor 2 (DDR2) as a crucial receptor that mediates this process in human fibroblasts...
March 7, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28267916/responsive-emulsion-gels-with-tunable-properties-formed-by-self-assembled-nanofibrils-of-natural-saponin-glycyrrhizic-acid-for-oil-structuring
#20
Zhili Wan, Yingen Sun, Lulu Ma, Xiaoquan Yang, Jian Guo, Shouwei Yin
Saponin nanofibrils assembled from natural glycyrrhizic acid (GA) have been recently shown to be an effective structurant for edible oil structuring. This work showed that the microstructure and mechanical properties of the novel emulsion gels formed by GA fibrils could be well tuned by oil phase polarity. For more polar oils (algal oil), the GA fibrils had a higher affinity to the oil-water interface, showing a faster adsorption kinetics, thus leading to the formation of fine multilayer emulsion droplets with smaller droplet size...
March 14, 2017: Journal of Agricultural and Food Chemistry
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