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https://www.readbyqxmd.com/read/28651195/stereological-and-biophysical-characteristics-of-the-ovine-surfactant-system-and-its-changes-caused-by-ovine-pulmonary-adenocarcinoma
#1
Ariane Jörger, Christa Acevedo, Diana Busley, Martin Ganter, Andreas Schmiedl, Esther Humann-Ziehank
Surfactant covers the inner surface of lung alveoli and lowers the surface tension to prevent alveoli from collapsing. A lack of surfactant or its dysfunction causes dyspnea. The Jaagsiekte Sheep Retrovirus (JSRV) causes ovine pulmonary adenocarcinoma (OPA), whose typical clinical appearance is fluid running from nostrils. This fluid might contain surfactant as alveolar type II pneumocytes (AEII) are target cells for JSRV. Therefore, the progressive dyspnea during OPA might be caused partially by surfactant alterations...
June 15, 2017: Research in Veterinary Science
https://www.readbyqxmd.com/read/28650961/mfpred-rapid-and-accurate-prediction-of-protein-peptide-recognition-multispecificity-using-self-consistent-mean-field-theory
#2
Aliza B Rubenstein, Manasi A Pethe, Sagar D Khare
Multispecificity-the ability of a single receptor protein molecule to interact with multiple substrates-is a hallmark of molecular recognition at protein-protein and protein-peptide interfaces, including enzyme-substrate complexes. The ability to perform structure-based prediction of multispecificity would aid in the identification of novel enzyme substrates, protein interaction partners, and enable design of novel enzymes targeted towards alternative substrates. The relatively slow speed of current biophysical, structure-based methods limits their use for prediction and, especially, design of multispecificity...
June 26, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28650586/a-complete-thermodynamic-analysis-of-enzyme-turnover-links-the-free-energy-landscape-to-enzyme-catalysis
#3
Hannah Bl Jones, Stephen A Wells, Erica J Prentice, Anthony Kwok, Liyin L Liang, Vickery L Arcus, Christopher R Pudney
Our understanding of how enzymes work is colored by static structure depictions where the enzyme scaffold is presented as either immobile, or in equilibrium between well-defined static conformations. Proteins however exhibit a large degree of motion over a broad range of timescales and magnitudes and this is defined thermodynamically by the enzyme free energy landscape (FEL). The role and importance of enzyme motion is extremely contentious. Much of the challenge is in the experimental detection of so called 'conformational sampling' involved in enzyme turnover...
June 26, 2017: FEBS Journal
https://www.readbyqxmd.com/read/28649768/measuring-canopy-loss-and-climatic-thresholds-from-an-extreme-drought-along-a-fivefold-precipitation-gradient-across-texas
#4
Amanda M Schwantes, Jennifer J Swenson, Mariano González-Roglich, Daniel M Johnson, Jean-Christophe Domec, Robert B Jackson
Globally, trees are increasingly dying from extreme drought, a trend that is expected to increase with climate change. Loss of trees has significant ecological, biophysical, and biogeochemical consequences. In 2011, a record drought caused widespread tree mortality in Texas. Using remotely sensed imagery, we quantified canopy loss during and after the drought across the state at 30-m spatial resolution, from the eastern pine/hardwood forests to the western shrublands, a region that includes the boundaries of many species ranges...
June 26, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28649195/modulating-stdp-balance-impacts-the-dendritic-mosaic
#5
Nicolangelo Iannella, Thomas Launey
The ability for cortical neurons to adapt their input/output characteristics and information processing capabilities ultimately relies on the interplay between synaptic plasticity, synapse location, and the nonlinear properties of the dendrite. Collectively, they shape both the strengths and spatial arrangements of convergent afferent inputs to neuronal dendrites. Recent experimental and theoretical studies support a clustered plasticity model, a view that synaptic plasticity promotes the formation of clusters or hotspots of synapses sharing similar properties...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28648851/the-influence-of-mild-acidity-on-lysyl-phosphatidylglycerol-biosynthesis-and-lipid-membrane-physico-chemical-properties-in-methicillin-resistant-staphylococcus-aureus
#6
Reg P Rehal, Helene Marbach, Alasdair T M Hubbard, Anam A Sacranie, Federica Sebastiani, Giovanna Fragneto, Richard D Harvey
The increased biosynthesis of lysyl-phosphatidylglycerol in Staphylococcus aureus when cultured under conditions of mild acidity and the resultant increased proportion of this lipid in the plasma membrane of the bacterium, alters the physico-chemical properties of lipid bilayers in a manner which is itself dependent upon environmental pH. Clinically relevant strains of S. aureus, both methicillin susceptible and resistant, all exhibited increased lysyl-phosphatidylglycerol biosynthesis in response to mild environmental acidity, albeit to differing degrees, from ∼30% to ∼55% total phospholipid...
June 22, 2017: Chemistry and Physics of Lipids
https://www.readbyqxmd.com/read/28648659/enterochromaffin-cells-are-gut-chemosensors-that-couple-to-sensory-neural-pathways
#7
Nicholas W Bellono, James R Bayrer, Duncan B Leitch, Joel Castro, Chuchu Zhang, Tracey A O'Donnell, Stuart M Brierley, Holly A Ingraham, David Julius
Dietary, microbial, and inflammatory factors modulate the gut-brain axis and influence physiological processes ranging from metabolism to cognition. The gut epithelium is a principal site for detecting such agents, but precisely how it communicates with neural elements is poorly understood. Serotonergic enterochromaffin (EC) cells are proposed to fulfill this role by acting as chemosensors, but understanding how these rare and unique cell types transduce chemosensory information to the nervous system has been hampered by their paucity and inaccessibility to single-cell measurements...
June 21, 2017: Cell
https://www.readbyqxmd.com/read/28648608/structures-of-pgam5-provide-insight-into-active-site-plasticity-and-multimeric-assembly
#8
Apirat Chaikuad, Panagis Filippakopoulos, Sean R Marcsisin, Sarah Picaud, Martin Schröder, Shiori Sekine, Hidenori Ichijo, John R Engen, Kohsuke Takeda, Stefan Knapp
PGAM5 is a mitochondrial membrane protein that functions as an atypical Ser/Thr phosphatase and is a regulator of oxidative stress response, necroptosis, and autophagy. Here we present several crystal structures of PGAM5 including the activating N-terminal regulatory sequences, providing a model for structural plasticity, dimerization of the catalytic domain, and the assembly into an enzymatically active dodecameric form. Oligomeric states observed in structures were supported by hydrogen exchange mass spectrometry, size-exclusion chromatography, and analytical ultracentrifugation experiments in solution...
June 10, 2017: Structure
https://www.readbyqxmd.com/read/28647357/biophysical-characterization-of-histone-h3-3-k27%C3%A2-m-point-mutation
#9
Szabolcs Hetey, Beáta Boros-Oláh, Tímea Kuik-Rózsa, Qiuzhen Li, Zsolt Karányi, Zoltán Szabó, Jason Roszik, Nikoletta Szalóki, György Vámosi, Katalin Tóth, Lóránt Székvölgyi
Lysine 27 to methionine (K27 M) mutation of the histone variant H3.3 drives the formation of an aggressive glioblastoma multiforme tumor in infants. Here we analyzed how the methionine substitution alters the stability of H3.3 nucleosomes in vitro and modifies its kinetic properties in live cells. We also determined whether the presence of mutant nucleosomes perturbed the mobility of the PRC2 subunit Ezh2 (enhancer-of-zeste homolog 2). We found that K27 M nucleosomes maintained the wild-type molecular architecture both at the level of bulk histones and single nucleosomes and followed similar diffusion kinetics to wild-type histones in live cells...
June 21, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28646215/single-molecule-and-multiple-bond-characterization-of-catch-bond-associated-cytoadhesion-in-malaria
#10
Ying Bena Lim, Juzar Thingna, Jianshu Cao, Chwee Teck Lim
The adhesion of malaria infected red blood cells (iRBCs) to host endothelial receptors in the microvasculature, or cytoadhesion, is associated with severe disease pathology such as multiple organ failure and cerebral malaria. Malaria iRBCs have been shown to bind to several receptors, of which intercellular adhesion molecule 1 (ICAM-1) upregulation in brain microvasculature is the only one correlated to cerebral malaria. We utilize a biophysical approach to study the interactions between iRBCs and ICAM-1. At the single molecule level, force spectroscopy experiments reveal that ICAM-1 forms catch bond interactions with Plasmodium falciparum parasite iRBCs...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28645929/biophysical-stimulation-for-in%C3%A2-vitro-engineering-of-functional-cardiac-tissues
#11
REVIEW
Anastasia Korolj, Erika Yan Wang, Robert A Civitarese, Milica Radisic
Engineering functional cardiac tissues remains an ongoing significant challenge due to the complexity of the native environment. However, our growing understanding of key parameters of the in vivo cardiac microenvironment and our ability to replicate those parameters in vitro are resulting in the development of increasingly sophisticated models of engineered cardiac tissues (ECT). This review examines some of the most relevant parameters that may be applied in culture leading to higher fidelity cardiac tissue models...
July 1, 2017: Clinical Science (1979-)
https://www.readbyqxmd.com/read/28645681/thermal-thresholds-of-cardiovascular-hl-1-cell-destruction-by-cryothermal-exposure
#12
Jeunghwan Choi, John Bischof
The use of thermal based therapies for treatment of atrial fibrillation is increasing [2,9]. While numerous reports are available in the literature regarding the efficacy of cryotherapy on pulmonary vein survival, there are no reports specifically at the cellular level that establish thermal thresholds and mechanisms of cellular destruction. The current article reports on the response of HL-1 cardiomyocytes to cooling rates and end temperatures during cryothermal exposure. The focus is on establishment of in vitro thresholds while also establishing mechanisms of action due to biophysical events (i...
June 20, 2017: Cryobiology
https://www.readbyqxmd.com/read/28645178/ecological-imperatives-for-aquatic-carbon-dioxide-concentrating-mechanisms
#13
Stephen C Maberly, Brigitte Gontero
In aquatic environments, the concentration of inorganic carbon is spatially and temporally variable and CO2 can be substantially oversaturated or depleted. Depletion of CO2 plus low rates of diffusion cause inorganic carbon to be more limiting in aquatic than terrestrial environments, and the frequency of species with a CO2-concentrating mechanism (CCM), and their contribution to productivity, is correspondingly greater. Aquatic photoautotrophs may have biochemical or biophysical CCMs and exploit CO2 from the sediment or the atmosphere...
June 22, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28644888/fragmentation-of-the-mitochondrial-network-in-skin-in-vivo
#14
Daniel Mellem, Martin Sattler, Sonja Pagel-Wolff, Sören Jaspers, Horst Wenck, Michael Alexander Rübhausen, Frank Fischer
Mitochondria form dynamic networks which adapt to the environmental requirements of the cell. We investigated the aging process of these networks in human skin cells in vivo by multiphoton microscopy. A study on the age-dependency of the mitochondrial network in young and old volunteers revealed that keratinocytes in old skin establish a significantly more fragmented network with smaller and more compact mitochondrial clusters than keratinocytes in young skin. Furthermore, we investigated the mitochondrial network during differentiation processes of keratinocytes within the epidermis of volunteers...
2017: PloS One
https://www.readbyqxmd.com/read/28644435/p53-amyloid-formation-leading-to-its-loss-of-function-implications-in-cancer-pathogenesis
#15
Saikat Ghosh, Shimul Salot, Shinjinee Sengupta, Ambuja Navalkar, Dhiman Ghosh, Reeba Jacob, Subhadeep Das, Rakesh Kumar, Narendra Nath Jha, Shruti Sahay, Surabhi Mehra, Ganesh M Mohite, Santanu K Ghosh, Mamata Kombrabail, Guruswamy Krishnamoorthy, Pradip Chaudhari, Samir K Maji
The transcriptional regulator p53 has an essential role in tumor suppression. Almost 50% of human cancers are associated with the loss of p53 functions, where p53 often accumulates in the nucleus as well as in cytoplasm. Although it has been previously suggested that amyloid formation could be a cause of p53 loss-of-function in subset of tumors, the characterization of these amyloids and its structure-function relationship is not yet established. In the current study, we provide several evidences for the presence of p53 amyloid formation (in human and animal cancer tissues); along with its isolation from human cancer tissues and the biophysical characterization of these tissue-derived fibrils...
June 23, 2017: Cell Death and Differentiation
https://www.readbyqxmd.com/read/28644379/physical-forces-may-cause-the-hoxd-gene-cluster-elongation
#16
Spyros Papageorgiou
Hox gene collinearity was discovered be Edward B. Lewis in 1978. It consists of the Hox1, Hox2, Hox3 ordering of the Hox genes in the chromosome from the telomeric to the centromeric side of the chromosome. Surprisingly, the spatial activation of the Hox genes in the ontogenetic units of the embryo follows the same ordering along the anterior-posterior embryonic axis. The chromosome microscale differs from the embryo macroscale by 3 to 4 orders of magnitude. The traditional biomolecular mechanisms are not adequate to comprise phenomena at so divergent spatial domains...
June 23, 2017: Biology
https://www.readbyqxmd.com/read/28644007/cyclotides-as-tools-in-chemical-biology
#17
Simon J de Veer, Joachim Weidmann, David J Craik
Among the various molecules that plants produce for defense against pests and pathogens, cyclotides stand out as exceptionally stable and structurally unique. These ribosomally synthesized peptides are around 30 amino acids in size, and are stabilized by a head-to-tail cyclic peptide backbone and three disulfide bonds that form a cystine knot. They occur in certain plants of the Rubiaceae, Violaceae, Cucurbitaceae, Fabaceae, and Solanaceae families, with an individual plant producing up to hundreds of different cyclotides...
June 23, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28643176/a-promising-tool-in-retina-regeneration-current-perspectives-and-challenges-when-using-mesenchymal-progenitor-stem-cells-in-veterinary-and-human-ophthalmological-applications
#18
REVIEW
Anna Cislo-Pakuluk, Krzysztof Marycz
Visual impairment is a common ailment of the current world population, with more exposure to CCD screens and fluorescent lighting, approximately 285 billion people suffer from this deficiency and 13% of those are considered clinically blind. More common causes for visual impairment include age-related macular degeneration (AMD), glaucoma and diabetic retinopathy (Zhu et al. Molecular Medicine Reports, 2015; Kolb et al. 2007; Machalińska et al. Current Eye Research, 34(9),748-760, 2009) among a few. As cases of retinal and optic nerve diseases rise, it is vital to find a treatment, which has led to investigation of the therapeutic potential of various stem cells types (Bull et al...
June 22, 2017: Stem Cell Reviews
https://www.readbyqxmd.com/read/28642967/strategies-for-characterization-of-enzymatic-nucleic-acids
#19
Fatemeh Javadi-Zarnaghi, Claudia Höbartner
Practical application of enzymatic nucleic acids has received more attention in recent years. Understanding the mechanism of catalysis and availability of information on potentials and limitations of these enzymes expands their application scope. A general approach for characterization of functional macromolecules including enzymatic nucleic acids is to perturb a specific set of condition and to follow the perturbation effect by biophysical and biochemical methods. This chapter reviews several perturbation strategies for functional nucleic acids, including deletion, mutation, and modifications of backbone and nucleobases, and consequent kinetic analysis, spectroscopic investigations, and probing assays...
June 23, 2017: Advances in Biochemical Engineering/biotechnology
https://www.readbyqxmd.com/read/28642152/g-quadruplex-dynamics
#20
REVIEW
Robert W Harkness, Anthony K Mittermaier
G-quadruplexes (GQs) are four-stranded nucleic acid secondary structures formed by guanosine (G)-rich DNA and RNA sequences. It is becoming increasingly clear that cellular processes including gene expression and mRNA translation are regulated by GQs. GQ structures have been extensively characterized, however little attention to date has been paid to their conformational dynamics, despite the fact that many biological GQ sequences populate multiple structures of similar free energies, leading to an ensemble of exchanging conformations...
June 19, 2017: Biochimica et Biophysica Acta
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