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https://www.readbyqxmd.com/read/29148800/size-and-shape-of-amyloid-fibrils-induced-by-ganglioside-nanoclusters-role-of-sialyl-oligosaccharide-in-fibril-formation
#1
Teruhiko Matsubara, Masaya Nishihara, Hanaki Yasumori, Mako Nakai, Katsuhiko Yanagisawa, Toshinori Sato
Ganglioside-enriched microdomains in the presynaptic neuronal membrane play a key role in the initiation of amyloid ß-protein (Aß) assembly related to Alzheimer's disease. We previously isolated lipids from a detergent-resistant membrane microdomain fraction of synaptosomes prepared from aged mouse brain and found that spherical Aß assemblies were formed on Aß-sensitive ganglioside nanoclusters (ASIGN) of reconstituted lipid bilayers in the synaptosomal fraction. In the present study, we investigated the role of oligosaccharides in Aß fibril formation induced by ganglioside-containing mixed lipid membranes that mimic the features of ASIGN...
November 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29148557/structural-and-thermodynamical-properties-of-early-human-amylin-oligomers-using-replica-exchange-molecular-dynamics-mutation-effect-of-three-key-residues-f15-h18-and-f23
#2
S Bouzakraoui, N Mousseau
Human islet amyloid polypeptide (hIAPP) is a 37-residue polypeptide, considered to be the main component of the pancreatic islet amyloid associated with type 2 diabetes and is one of the most amyloidogenic polypeptides known. Although the structure of hIAPP fibrils has already been obtained, structures of early oligomers and the mechanism of β-sheet formation remain poorly understood. Herein, we characterize the atomic structure and the thermodynamics of the 14-37 residue fragment of hIAPP wild-type and mutated dimers and trimers...
November 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29148083/macroscopic-and-microscopic-analyses-in-flexor-tendons-of-the-tarsometatarso-phalangeal-joint-of-ostrich-struthio-camelus-foot-with-energy-storage-and-shock-absorption
#3
Rui Zhang, Dianlei Han, Gang Luo, Lei Ling, Guoyu Li, Qiaoli Ji, Jianqiao Li
Flexor tendons function as energy storage and shock absorption structures in the tarsometatarso-phalangeal joint (TMTPJ) of ostrich feet during high-speed and heavy-load locomotion. In this study, mechanisms underlying the energy storage and shock absorption of three flexor tendons of the third toe were studied using histology and scanning electron microscopy (SEM). Macroscopic and microscopic structures of the flexor tendons in different positions of TMTPJ were analyzed. Histological slices showed collagen fiber bundles of all flexor tendons in the middle TMTPJ were arranged in a linear-type, but in the proximal and distal TMTPJ, a wavy-type arrangement was found in the tendon of the M...
November 17, 2017: Journal of Morphology
https://www.readbyqxmd.com/read/29147836/effects-of-saffron%C3%A2-and-its-constituents-%C3%A2-crocin-1-crocin-2-and-crocetin-on-%C3%AE-synuclein-fibrils
#4
Eiji Inoue, Yasuharu Shimizu, Ryo Masui, Tomomi Hayakawa, Tomoe Tsubonoya, Satoko Hori, Keiichi Sudoh
Saffron, the stigma of Crocus sativus Linné (Iridaceae family), has been known to inhibit aggregation of β-amyloid, a nerve tissue protein. α-Synuclein (αS) is a 140-amino acid protein found abundantly in various regions of the brain. Its abnormal aggregation and accumulation in nerve tissue are said to cause neurodegenerative diseases such as Parkinson's disease, Lewy body dementia, and multiple-system atrophy. This study (part of this study was presented at the 137th Annual Meeting of the Pharmaceutical Society of Japan) examined the effects of saffron, its constituents (crocin-1, crocin-2, crocetin, and safranal), and crocetin structural analogs (hexadecanedioic acid, norbixin, and trans, trans-muconic acid) on αS aggregation, and αS fibril dissociation...
November 17, 2017: Journal of Natural Medicines
https://www.readbyqxmd.com/read/29147557/the-diversity-and-utility-of-amyloid-fibrils-formed-by-short-amyloidogenic-peptides
#5
REVIEW
Zahraa S Al-Garawi, Kyle L Morris, Karen E Marshall, Jutta Eichler, Louise C Serpell
Amyloidogenic peptides are well known for their involvement in diseases such as type 2 diabetes and Alzheimer's disease. However, more recently, amyloid fibrils have been shown to provide scaffolding and protection as functional materials in a range of organisms from bacteria to humans. These roles highlight the incredible tensile strength of the cross-β amyloid architecture. Many amino acid sequences are able to self-assemble to form amyloid with a cross-β core. Here we describe our recent advances in understanding how sequence contributes to amyloidogenicity and structure...
December 6, 2017: Interface Focus
https://www.readbyqxmd.com/read/29147551/development-of-proteolytically-stable-n-methylated-peptide-inhibitors-of-aggregation-of-the-amylin-peptide-implicated-in-type-2-diabetes
#6
Idira Obasse, Mark Taylor, Nigel J Fullwood, David Allsop
Islet amyloid polypeptide, also known as amylin, is the main component of the amyloid deposits present in approximately 90% of people with type 2 diabetes mellitus (T2DM). In this disease, amylin aggregates into multimeric β-pleated sheet structures which cause damage to pancreatic islet β-cells. Inhibitors of early-stage amylin aggregation could therefore provide a disease-modifying treatment for T2DM. In this study, overlapping peptides were designed to target the 'binding' region (RLANFLVHSS, residues 11-20) of human amylin, and their effects on amyloid fibril formation were determined by thioflavin-T assay...
December 6, 2017: Interface Focus
https://www.readbyqxmd.com/read/29147549/redox-sensitive-reversible-self-assembly-of-amino-acid-naphthalene-diimide-conjugates
#7
Wathsala Liyanage, Paul W Rubeo, Bradley L Nilsson
Peptide and low molecular weight amino acid-based materials that self-assemble in response to environmental triggers are highly desirable candidates in forming functional materials with tunable biophysical properties. In this paper, we explore redox-sensitive self-assembly of cationic phenylalanine derivatives conjugated to naphthalene diimide (NDI). Self-assembly of the cationic Phe-NDI conjugates into nanofibrils was induced in aqueous solvent at high ionic strength. Under reducing conditions, these self-assembled Phe-NDI conjugate fibrils underwent a morphological change to non-fibril aggregates...
December 6, 2017: Interface Focus
https://www.readbyqxmd.com/read/29145303/epicardial-radiofrequency-catheter-ablation-of-brugada-syndrome-with-electrical-storm-during-ventricular-fibrillation-a-case-report
#8
Shufen Jiang, Xiaomeng Yin, Chang Dong, Yunlong Xia, Jinqiu Liu
RATIONALE: Brugada syndrome (BrS) is characterized by ST segment elevation at the J point ≥2 mm in the right precordial electrocardiogram (ECG) leads, in the absence of structural heart disease, electrolyte disturbances, or ischemia. It is a well-described cause of sudden death in young patients, especially in the age of between 30 and 40 years old. Here, we reported an unusual case of electrical storm (ES) of ventricular fibrillation (VF) caused by BrS with complete right bundle-branch block (CRBBB) in a 75-year-old male patient...
November 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/29145016/thermal-effect-on-the-degradation-of-hiapp20-29-fibrils
#9
H X Zhang, Lei Liu, Jie Wang, Christian Bortolini, Mingdong Dong
Uncontrolled misfolding of proteins resulting in the formation of amyloid deposits is associated with over 40 types of diseases, for instance, type-2 diabetes. The human Islet amyloid polypeptide (hIAPP) amyloid formation is thought to be the cause of type-2 diabetes occurrence. A possible strategy to the current challenge of reducing the toxicity of its aggregates to pancreatic β-cell is the discovery of an efficient way to degrading amyloid deposits. In this work, hIAPP20-29, a core fibrillating fragment of hIAPP, was selected as model system to explore the thermal effect at different temperature on the degradation of hIAPP20-29 mature fibrils...
October 31, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29144442/propagation-of-fibrillar-structural-forms-in-proteins-stopped-by-naturally-occurring-short-polypeptide-chain-fragments
#10
Irena Roterman, Mateusz Banach, Leszek Konieczny
Amyloids characterized by unbounded growth of fibrillar structures cause many pathological processes. Such unbounded propagation is due to the presence of a propagating hydrophobicity field around the fibril's main axis, preventing its closure (unlike in globular proteins). Interestingly, similar fragments, commonly referred to as solenoids, are present in many naturally occurring proteins, where their propagation is arrested by suitably located "stopper" fragments. In this work, we analyze the distribution of hydrophobicity in solenoids and in their corresponding "stoppers" from the point of view of the fuzzy oil drop model (called FOD in this paper)...
November 16, 2017: Pharmaceuticals
https://www.readbyqxmd.com/read/29144022/collagen-a-review-on-its-sources-and-potential-cosmetic-applications
#11
REVIEW
María Isabela Avila Rodríguez, Laura G Rodríguez Barroso, Mirna Lorena Sánchez
Collagen is a fibrillar protein that conforms the conjunctive and connective tissues in the human body, essentially skin, joints, and bones. This molecule is one of the most abundant in many of the living organisms due to its connective role in biological structures. Due to its abundance, strength and its directly proportional relation with skin aging, collagen has gained great interest in the cosmetic industry. It has been established that the collagen fibers are damaged with the pass of time, losing thickness and strength which has been strongly related with skin aging phenomena [Colágeno para todo...
November 16, 2017: Journal of Cosmetic Dermatology
https://www.readbyqxmd.com/read/29143447/investigation-of-the-interactions-between-aptamer-and-misfolded-proteins-from-monomer-and-oligomer-to-fibril-by-single-molecule-force-spectroscopy
#12
Yan Zheng, Qing Wang, Xiaohai Yang, Zhiping Li, Lei Gao, Hua Zhang, Wenyan Nie, Xiuhua Geng, Kemin Wang
Increasing knowledge on the understanding interactions of aptamer with misfolded proteins (including monomer, oligomer, and amyloid fibril) is crucial for development of aggregation inhibitors and diagnosis of amyloid diseases. Herein, the interactions of lysozyme monomer-, oligomer-, and amyloid fibril-aptamer were investigated using single-molecule force spectroscopy. The results revealed that the aptamer screened against lysozyme monomer could also bind to oligomer and amyloid fibril, in spite of the recognition at a lower binding probability...
November 16, 2017: Journal of Molecular Recognition: JMR
https://www.readbyqxmd.com/read/29143443/multiscale-characterisation-of-cortical-bone-composition-microstructure-and-nanomechanical-properties-in-experimentally-induced-osteoporosis
#13
Furqan A Shah, Adrian Stoica, Carina Cardemil, Anders Palmquist
Cortical bone plays a vital role in determining overall bone strength. We investigate the structural, compositional, and nanomechanical properties of cortical bone following ovariectomy (OVX) of 12 week old Sprague Dawley rats, since this animal model is frequently employed to evaluate the performance of implantable biomaterials in compromised bone healing conditions. Morphological parameters and material properties of bone in the geometrical centre of the femoral cortex were investigated four and eight weeks post-OVX and in unoperated controls (Ctrl), using X-ray micro-computed tomography, backscattered electron scanning electron microscopy, Raman spectroscopy, and nanoindentation...
November 16, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/29143099/-left-atrial-appendage-clusure-in-nonvalvular-atrial-fibrillation-clinical-evidence-2017
#14
REVIEW
Steffen Gloekler, Bajram Hajredini, Simon Rycerz, Sebastian Jäckle, Werner Jung
Nonvalvular atrial fibrillation (AF) is the most common arrhythmia with a prevalence of 1-2% and affects approximately 15-20% of all octogenarians. Patients are at increased risk of thromboembolic stroke, with an overall risk of 5% per year. Thrombi form almost exclusively in the left atrial appendage (LAA), a blind sac-like heterogeneous structure trabeculated by pectinate muscles. In the past five decades, life-long oral anticoagulation (OAC) with vitamin K antagonists (VKA) has been the state-of-the art treatment to prevent stroke and systemic embolism from thrombi in AF...
November 15, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/29141778/pathophysiology-and-risk-of-atrial-fibrillation-detected-after-ischemic-stroke-paradise-a-translational-integrated-and-transdisciplinary-approach
#15
Maryse Paquet, Joshua O Cerasuolo, Victoria Thorburn, Sebastian Fridman, Rasha Alsubaie, Renato D Lopes, Lauren E Cipriano, Paula Salamone, C W James Melling, Ali R Khan, Lucas Sedeño, Jiming Fang, Maria Drangova, Manuel Montero-Odasso, Jennifer Mandzia, Alexander V Khaw, Juan M Racosta, Justin Paturel, Lucy Samoilov, Devin Stirling, Brittany Balint, Victoria Jaremek, Marlys L Koschinsky, Michael B Boffa, Kelly Summers, Agustín Ibañez, Marko Mrkobrada, Gustavo Saposnik, Kurt Kimpinski, Shawn N Whitehead, Luciano A Sposato
BACKGROUND: It has been hypothesized that ischemic stroke can cause atrial fibrillation. By elucidating the mechanisms of neurogenically mediated paroxysmal atrial fibrillation, novel therapeutic strategies could be developed to prevent atrial fibrillation occurrence and perpetuation after stroke. This could result in fewer recurrent strokes and deaths, a reduction or delay in dementia onset, and in the lessening of the functional, structural, and metabolic consequences of atrial fibrillation on the heart...
November 13, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/29140083/a-critical-role-of-ser26-hydrogen-bonding-in-a%C3%AE-42-assembly-and-toxicity
#16
Robin Roychaudhuri, Tien-Phat V Huynh, Taylor R Whitaker, Elisabeth Hodara, Margaret M Condron, David B Teplow
Amyloid β-protein (Aβ) assembly is a seminal process in Alzheimer's disease. Elucidating the mechanistic features of this process is thought to be vital for the design and targeting of therapeutic agents. Com-putational studies of the most pathologic form of Aβ, the 42-residue Aβ42 peptide, have suggested that hydrogen bonding involving Ser 26 may be particularly important in organizing a monomer folding nucleus and in subse-quent peptide assembly. To study this question, we ex-perimentally determined structure-activity relationships among Aβ42 peptides in which Ser 26 was replaced with Gly, Ala, α-aminobutryic acid (Abu), or Cys...
November 15, 2017: Biochemistry
https://www.readbyqxmd.com/read/29139545/the-effect-of-ice-crystals-formations-on-the-flesh-quality-of-frozen-horse-mackerel-trachurus-japonicus
#17
Yao Wang, Riho Miyazaki, Shinobu Saitou, Katsuya Hirasaka, Satoshi Takeshita, Katsuyasu Tachibana, Shigeto Taniyama
It is known that the formation of ice crystals has a negative impact on the flesh quality of frozen meat. This study focuses on how the formation of ice crystals in the dorsal ordinary muscle affects the flesh quality of frozen horse mackerel (Trachurus japonicus). Freeze-thawed muscle specimens (F-TMS) of horse mackerel were first stored at -24°C and then thawed. The K-value, expressible water, breaking strength of unfrozen muscle specimens (UMS) and F-TMS, and histological structure (light microscope: LM, scanning electron microscope: SEM) of UMS, frozen muscle specimens (FMS) and F-TMS were investigated...
November 15, 2017: Journal of Texture Studies
https://www.readbyqxmd.com/read/29137726/mineralized-collagen-fibril-network-spatial-arrangement-influences-cortical-bone-fracture-behavior
#18
Yaohui Wang, Ani Ural
Bone is a hierarchical material exhibiting different fracture mechanisms at each length scale. At the submicroscale, the bone is composed of mineralized collagen fibrils (MCF). At this scale, the fracture processes in cortical bone have not been extensively studied in the literature. In this study, the influence of MCF size and orientation on the fracture behavior of bone under both transverse and longitudinal loading was investigated using novel 3D models of MCF networks with explicit representation of extra-fibrillar matrix...
November 4, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29133814/structural-remodeling-and-oligomerization-of-human-cathelicidin-on-membranes-suggest-fibril-like-structures-as-active-species
#19
Enea Sancho-Vaello, Patrice François, Eve-Julie Bonetti, Hauke Lilie, Sebastian Finger, Fernando Gil-Ortiz, David Gil-Carton, Kornelius Zeth
Antimicrobial peptides as part of the mammalian innate immune system target and remove major bacterial pathogens, often through irreversible damage of their cellular membranes. To explore the mechanism by which the important cathelicidin peptide LL-37 of the human innate immune system interacts with membranes, we performed biochemical, biophysical and structural studies. The crystal structure of LL-37 displays dimers of anti-parallel helices and the formation of amphipathic surfaces. Peptide-detergent interactions introduce remodeling of this structure after occupation of defined hydrophobic sites at the dimer interface...
November 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29133380/atrial-substrate-and-triggers-of-paroxysmal-atrial-fibrillation-in-patients-with-obstructive-sleep-apnea
#20
Elad Anter, Luigi Di Biase, Fernando M Contreras-Valdes, Carola Gianni, Sanghamitra Mohanty, Cory M Tschabrunn, Juan F Viles-Gonzalez, Eran Leshem, Alfred E Buxton, Guy Kulbak, Rim N Halaby, Peter J Zimetbaum, Jonathan W Waks, Robert J Thomas, Andrea Natale, Mark E Josephson
BACKGROUND: Obstructive sleep apnea (OSA) is associated with atrial remodeling, atrial fibrillation (AF), and increased incidence of arrhythmia recurrence after pulmonary vein (PV) isolation. We aimed to characterize the atrial substrate, including AF triggers in patients with paroxysmal AF and OSA. METHODS AND RESULTS: In 86 patients with paroxysmal AF (43 with ≥moderate OSA [apnea-hypopnea index ≥15] and 43 without OSA [apnea-hypopnea index <5]), right atrial and left atrial voltage distribution, conduction velocities, and electrogram characteristics were analyzed during atrial pacing...
November 2017: Circulation. Arrhythmia and Electrophysiology
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