keyword
MENU ▼
Read by QxMD icon Read
search

Biophysics

keyword
https://www.readbyqxmd.com/read/27910869/multiparameter-mechanical-and-morphometric-screening-of-cells
#1
Mahdokht Masaeli, Dewal Gupta, Sean O'Byrne, Henry T K Tse, Daniel R Gossett, Peter Tseng, Andrew S Utada, Hea-Jin Jung, Stephen Young, Amander T Clark, Dino Di Carlo
We introduce a label-free method to rapidly phenotype and classify cells purely based on physical properties. We extract 15 biophysical parameters from cells as they deform in a microfluidic stretching flow field via high-speed microscopy and apply machine-learning approaches to discriminate different cell types and states. When employing the full 15 dimensional dataset, the technique robustly classifies individual cells based on their pluripotency, with accuracy above 95%. Rheological and morphological properties of cells while deforming were critical for this classification...
December 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27909841/the-shaping-of-intrinsic-membrane-potential-oscillations-positive-negative-feedback-ionic-resonance-amplification-nonlinearities-and-time-scales
#2
Horacio G Rotstein
The generation of intrinsic subthreshold (membrane potential) oscillations (STOs) in neuronal models requires the interaction between two processes: a relatively fast positive feedback that favors changes in voltage and a slower negative feedback that opposes these changes. These are provided by the so-called resonant and amplifying gating variables associated to the participating ionic currents. We investigate both the biophysical and dynamic mechanisms of generation of STOs and how their attributes (frequency and amplitude) depend on the model parameters for biophysical (conductance-based) models having qualitatively different types of resonant currents (activating and inactivating) and an amplifying current...
December 1, 2016: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/27909394/metabolic-energy-of-action-potentials-modulated-by-spike-frequency-adaptation
#3
Guo-Sheng Yi, Jiang Wang, Hui-Yan Li, Xi-Le Wei, Bin Deng
Spike frequency adaptation (SFA) exists in many types of neurons, which has been demonstrated to improve their abilities to process incoming information by synapses. The major carrier used by a neuron to convey synaptic signals is the sequences of action potentials (APs), which have to consume substantial metabolic energies to initiate and propagate. Here we use conductance-based models to investigate how SFA modulates the AP-related energy of neurons. The SFA is attributed to either calcium-activated K(+) (IAHP) or voltage-activated K(+) (IM) current...
2016: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/27909292/crystal-structures-of-the-tric-trimeric-intracellular-cation-channel-orthologues
#4
Go Kasuya, Masahiro Hiraizumi, Andrés D Maturana, Kaoru Kumazaki, Yuichiro Fujiwara, Keihong Liu, Yoshiko Nakada-Nakura, So Iwata, Keisuke Tsukada, Tomotaka Komori, Sotaro Uemura, Yuhei Goto, Takanori Nakane, Mizuki Takemoto, Hideaki E Kato, Keitaro Yamashita, Miki Wada, Koichi Ito, Ryuichiro Ishitani, Motoyuki Hattori, Osamu Nureki
Ca(2+) release from the sarcoplasmic reticulum (SR) and endoplasmic reticulum (ER) is crucial for muscle contraction, cell growth, apoptosis, learning and memory. The trimeric intracellular cation (TRIC) channels were recently identified as cation channels balancing the SR and ER membrane potentials, and are implicated in Ca(2+) signaling and homeostasis. Here we present the crystal structures of prokaryotic TRIC channels in the closed state and structure-based functional analyses of prokaryotic and eukaryotic TRIC channels...
December 2016: Cell Research
https://www.readbyqxmd.com/read/27908751/enhanced-potency-of-bivalent-small-molecule-gp41-inhibitors
#5
Vladimir Sofiyev, Hardeep Kaur, Beth A Snyder, Priscilla A Hogan, Roger G Ptak, Peter Hwang, Miriam Gochin
Low molecular weight peptidomimetic inhibitors with hydrophobic pocket binding properties and moderate fusion inhibitory activity against HIV-1 gp41-mediated cell fusion were elaborated by increasing the available surface area for interacting with the heptad repeat-1 (HR1) coiled coil on gp41. Two types of modifications were tested: 1) increasing the overall hydrophobicity of the molecules with an extension that could interact in the HR1 groove, and 2) forming symmetrical dimers with two peptidomimetic motifs that could potentially interact simultaneously in two hydrophobic pockets on the HR1 trimer...
November 19, 2016: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/27908538/antimalarial-activity-of-novel-4-aminoquinolines-active-against-drug-resistant-strains
#6
Srinivasarao Kondaparla, Awakash Soni, Ashan Manhas, Kumkum Srivastava, Sunil K Puri, S B Katti
In the present study we have synthesized a new class of 4-aminoquinolines and evaluated against Plasmodium falciparum in vitro (3D7-sensitive strain & K1-resistant strain) and Plasmodium yoelii in vivo (N-67 strain). Among the series, eleven compounds (5, 6, 7, 8, 9, 11, 12, 13, 14, 15 and 21) showed superior antimalarial activity against K1 strain as compared to CQ. In addition, all these analogues showed 100% suppression of parasitemia on day 4 in the in vivo mouse model against N-67 strain when administered orally...
November 23, 2016: Bioorganic Chemistry
https://www.readbyqxmd.com/read/27908508/editorial-overview-biophysical-and-molecular-biological-methods
#7
EDITORIAL
Petra Fromme, Andrej Sali
No abstract text is available yet for this article.
November 28, 2016: Current Opinion in Structural Biology
https://www.readbyqxmd.com/read/27908120/lipid-phase-behavior-studied-with-a-quartz-crystal-microbalance-a-technique-for-biophysical-studies-with-applications-in-screening
#8
Astrid Peschel, Arne Langhoff, Eva Uhl, Aruna Dathathreyan, Susanne Haindl, Diethelm Johannsmann, Ilya Reviakine
Quartz crystal microbalance (QCM) is emerging as a versatile tool for studying lipid phase behavior. The technique is attractive for fundamental biophysical studies as well applications because of its simplicity, flexibility, and ability to work with very small amounts of material crucial for biomedical studies. Further progress hinges on the understanding of the mechanism, by which a surface-acoustic technique such as QCM, senses lipid phase changes. Here, we use a custom-built instrument with improved sensitivity to investigate phase behavior in solid-supported lipid systems of different geometries (adsorbed liposomes and bilayers)...
November 28, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27908109/perturbation-of-hydration-layer-in-solvated-proteins-by-external-electric-and-electromagnetic-fields-insights-from-non-equilibrium-molecular-dynamics
#9
Prithwish K Nandi, Zdenek Futera, Niall J English
Given the fundamental role of water in governing the biochemistry of enzymes, and in regulating their wider biological activity (e.g., by local water concentration surrounding biomolecules), the influence of extraneous electric and electromagnetic (e/m) fields thereon is of central relevance to biophysics and, more widely, biology. With the increase in levels of local and atmospheric microwave-frequency radiation present in modern life, as well as other electric-field exposure, the impact upon hydration-water layers surrounding proteins, and biomolecules generally, becomes a particularly pertinent issue...
November 28, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27907865/biophysical-characterization-and-antineoplastic-activity-of-new-bis-thiosemicarbazonato-cu-ii-complexes
#10
Elisa Palma, Filipa Mendes, Goreti Ribeiro Morais, Inês Rodrigues, Isabel Cordeiro Santos, Maria Paula C Campello, Paula Raposinho, Isabel Correia, Sofia Gama, Dulce Belo, Vítor Alves, Antero J Abrunhosa, Isabel Santos, António Paulo
Aiming to explore alternative mechanisms of cellular uptake and cytotoxicity, we have studied a new family of copper(II) complexes (CuL(1)-CuL(4)) with bis(thiosemicarbazone) (BTSC) ligands containing pendant protonable cyclic amines (morpholine and piperidine). Herein, we report on the synthesis and characterization of these new complexes, as well as on their biological performance (cytotoxic activity, cellular uptake, protein and DNA binding), in comparison with the parental Cu(II)ATSM (ATSM=diacetyl-bis(N4-methylthiosemicarbazonate) complex without pendant cyclic amines...
November 23, 2016: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/27907857/membrane-effects-of-dihydropyrimidine-analogues-with-larvicidal-activity
#11
Mariela E Sánchez-Borzone, Maria E Mariani, Virginia Miguel, Raquel M Gleiser, Bharti Odhav, Katharigatta N Venugopala, Daniel A García
Two recently synthesized dihydropyrimidines (DHPMs) analogues have demonstrated larvicide and repellent activity against Anopheles arabiensis. DHPMs high lipophilicity suggests that these compounds may interact directly with the membrane and modify their biophysical properties. The purpose of the present study was to characterize the interaction of both compounds with artificial membranes. Changes on the properties of DPPC films were studied using Langmuir monolayers. The presence of DHPMs in the subphase modified the interfacial characteristics of DPPC compression isotherms, causing the expansion of the monolayer, inducing the disappearance of DPPC phase transition and increasing the molecular packing of the film...
November 24, 2016: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/27906314/biophysical-modelling-of-phytoplankton-communities-from-first-principles-using-two-layered-spheres-equivalent-algal-populations-eap-model-erratum
#12
Lisl Robertson Lain, Stewart Bernard, Mark W Matthews
We regret that the Rrs spectra shown for the EAP modelled high biomass validation in Fig. 7 [Opt. Express, 22, 16745 (2014)] are incorrect. They are corrected here. The closest match of modelled to measured effective diameter is for a generalised 16 μm dinoflagellate population and not a 12 μm one as previously stated. These corrections do not affect the discussion or the conclusions of the paper.
November 28, 2016: Optics Express
https://www.readbyqxmd.com/read/27906134/tumour-suppressor-micrornas-regulate-ovarian-cancer-cell-physical-properties-and-invasive-behaviour
#13
Clara K Chan, Yinghong Pan, Kendra Nyberg, Marco A Marra, Emilia L Lim, Steven J M Jones, Dianna Maar, Ewan A Gibb, Preethi H Gunaratne, A Gordon Robertson, Amy C Rowat
The activities of pathways that regulate malignant transformation can be influenced by microRNAs (miRs). Recently, we showed that increased expression of five tumour-suppressor miRs, miR-508-3p, miR-508-5p, miR-509-3p, miR-509-5p and miR-130b-3p, correlate with improved clinical outcomes in human ovarian cancer patients, and that miR-509-3p attenuates invasion of ovarian cancer cell lines. Here, we investigate the mechanism underlying this reduced invasive potential by assessing the impact of these five miRs on the physical properties of cells...
November 2016: Open Biology
https://www.readbyqxmd.com/read/27905603/pathological-levels-of-glucosylceramide-change-the-biophysical-properties-of-artificial-and-cell-membranes
#14
Ana R P Varela, Ana E Ventura, Ana C Carreira, Aleksander Fedorov, Anthony H Futerman, Manuel Prieto, Liana C Silva
Glucosylceramide (GlcCer) plays an active role in the regulation of various cellular events. Moreover, GlcCer is also a key modulator of membrane biophysical properties, which might be linked to the mechanism of its biological action. In order to understand the biophysical implications of GlcCer on membranes of living cells, we first studied the effect of GlcCer on artificial membranes containing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), sphingomyelin (SM) and cholesterol (Chol). Using an array of biophysical methods, we demonstrate that at lower GlcCer/Chol ratios, GlcCer stabilizes SM/Chol-enriched liquid-ordered domains...
December 1, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27905559/sailfish-migrations-connect-productive-coastal-areas-in-the-west-atlantic-ocean
#15
Chi Hin Lam, Benjamin Galuardi, Anthony Mendillo, Emily Chandler, Molly E Lutcavage
Isla Mujeres, Mexico is home to one of the most well-known aggregations of sailfish. Despite its fisheries prominence, little is known about this sailfish assemblage, or its relationship to other aggregation sites in the western Atlantic. In January 2012, April 2013 and 2014, we deployed 34 popup satellite archival tags on sailfish in order to study their behavior, population connectivity and biophysical interactions. Sailfish were monitored for up to one year, and displayed (1) predominantly shelf associated activity (2) occupancy of the Yucatán Current near Isla Mujeres for up to five months and (3) subsequent dispersals from the Yucatán to productive coastal areas in the Gulf of Mexico, the Caribbean Sea and along the South American coast...
December 1, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27905530/structural-basis-for-broad-neutralization-of-hiv-1-through-the-molecular-recognition-of-10e8-helical-epitope-at-the-membrane-interface
#16
Edurne Rujas, Jose M M Caaveiro, Angélica Partida-Hanon, Naveed Gulzar, Koldo Morante, Beatriz Apellániz, Miguel García-Porras, Marta Bruix, Kouhei Tsumoto, Jamie K Scott, M Ángeles Jiménez, José L Nieva
The mechanism by which the HIV-1 MPER epitope is recognized by the potent neutralizing antibody 10E8 at membrane interfaces remains poorly understood. To solve this problem, we have optimized a 10E8 peptide epitope and analyzed the structure and binding activities of the antibody in membrane and membrane-like environments. The X-ray crystal structure of the Fab-peptide complex in detergents revealed for the first time that the epitope of 10E8 comprises a continuous helix spanning the gp41 MPER/transmembrane domain junction (MPER-N-TMD; Env residues 671-687)...
December 1, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27904454/red-blood-cell-transfusion-and-skeletal-muscle-tissue-oxygenation-in-anaemic-haematologic-outpatients
#17
Matej Podbregar, Ana Ursula Gavric, Eva Podbregar, Hugon Mozina, Sebastian Stefanovic
BACKGROUND: Stored red blood cells (RBCs) accumulate biochemical and biophysical changes, known as storage lesion. The aim of this study was to re-challenge current data that anaemia in chronically anaemic haematology patients is not associated with low skeletal muscle tissue oxygen (StO2), and that RBC storage age does not influence the tissue response after ischaemic provocation, using near-infrared spectroscopy. PATIENTS AND METHODS: Twenty-four chronic anaemic haematology patients were included...
December 1, 2016: Radiology and Oncology
https://www.readbyqxmd.com/read/27904203/daytime-changes-of-skin-biophysical-characteristics-a-study-of-hydration-transepidermal-water-loss-ph-sebum-elasticity-erythema-and-color-index-on-middle-eastern-skin
#18
Alireza Firooz, Hamed Zartab, Bardia Sadr, Leili Naraghi Bagherpour, Aidin Masoudi, Ferial Fanian, Yahya Dowlati, Amir Hooshang Ehsani, Aniseh Samadi
BACKGROUND: The exposure of skin to ultraviolet radiation and temperature differs significantly during the day. It is reasonable that biophysical parameters of human skin have periodic daily fluctuation. The objective of this study was to study the fluctuations of various biophysical characteristics of Middle Eastern skin in standardized experimental conditions. MATERIALS AND METHODS: Seven biophysical parameters of skin including stratum corneum hydration, transepidermal water loss, pH, sebum, elasticity, skin color, and erythema index were measured at three time points (8 a...
November 2016: Indian Journal of Dermatology
https://www.readbyqxmd.com/read/27903914/proteomic-analysis-of-the-human-keops-complex-identifies-c14orf142-as-a-core-subunit-homologous-to-yeast-gon7
#19
Leo C K Wan, Pierre Maisonneuve, Rachel K Szilard, Jean-Philippe Lambert, Timothy F Ng, Noah Manczyk, Hao Huang, Rob Laister, Amy A Caudy, Anne-Claude Gingras, Daniel Durocher, Frank Sicheri
The KEOPS/EKC complex is a tRNA modification complex involved in the biosynthesis of N(6)-threonylcarbamoyladenosine (t(6)A), a universally conserved tRNA modification found on ANN-codon recognizing tRNAs. In archaea and eukaryotes, KEOPS is composed of OSGEP/Kae1, PRPK/Bud32, TPRKB/Cgi121 and LAGE3/Pcc1. In fungi, KEOPS contains an additional subunit, Gon7, whose orthologs outside of fungi, if existent, remain unidentified. In addition to displaying defective t(6)A biosynthesis, Saccharomyces cerevisiae strains harboring KEOPS mutations are compromised for telomere homeostasis, growth and transcriptional co-activation...
November 29, 2016: Nucleic Acids Research
https://www.readbyqxmd.com/read/27903587/changes-in-mitochondrial-morphology-and-organisation-can-enhance-energy-supply-from-mitochondrial-oxidative-phosphorylation-in-diabetic-cardiomyopathy
#20
Jan Jarosz, Shouryadipta Ghosh, Lea M D Delbridge, Amorita Volschenk, Anthony Jr Hickey, Edmund J Crampin, Eric Hanssen, Vijay Rajagopal
Diabetic cardiomyopathy is accompanied by metabolic and ultrastructural alterations, but the impact of the structural changes on metabolism itself is yet to be determined. Morphometric analysis of mitochondrial shape and spatial organisation within transverse sections of cardiomyocytes from control and streptozotocin induced type I diabetic Sprague-Dawley rats revealed that mitochondria are 20% smaller in size while their spatial density increases by 53% in diabetic cells relative to control myocytes. Diabetic cells formed larger clusters of mitochondria (60% more mitochondria per cluster) and the effective surface to volume ratio of these clusters increased by 22...
November 30, 2016: American Journal of Physiology. Cell Physiology
keyword
keyword
7837
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"