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Hwankyu Lee
Polyelectrolyte bilayers, which consist of poly-l-lysine (PLL) and hyaluronic acid (HA) were simulated with lipid membranes at different temperatures and ion concentrations. Starting with the sequential deposition of PLL and HA above the membrane surface, PLL and HA become completely mixed, leading to the formation of stable bilayers. PLL/HA bilayers are thicker at higher salt concentration because of weakened electrostatic interactions between PLLs and membrane lipids, in agreement with experiments. This salt effect decreases as PLL size increases...
September 23, 2016: Journal of Molecular Graphics & Modelling
Lin Cheng, Matthew D Blackledge, David J Collins, Matthew R Orton, Neil P Jerome, Thorsten Feiweier, Mihaela Rata, Veronica Morgan, Nina Tunariu, Martin O Leach, Dow-Mu Koh
PURPOSE: To introduce T2-adjusted computed DWI (T2-cDWI), a method that provides synthetic images at arbitrary b-values and echo times (TEs) that improve tissue contrast by removing or increasing T2 contrast in diffusion-weighted images. MATERIALS AND METHODS: In addition to the standard DWI acquisition protocol T2-weighted echo-planar images at multiple (≥2) echo times were acquired. This allows voxelwise estimation of apparent diffusion coefficient (ADC) and T2 values, permitting synthetic images to be generated at any chosen b-value and echo time...
October 1, 2016: Computers in Biology and Medicine
Riikka Homanen
This article discusses practices of parental support in the maternity healthcare provided by the welfare state. Drawing on ethnographic material from clinics in Finland, I discuss maternity healthcare practices and processes as the specific contexts of subjectification to parenthood in the Nordic welfare state. The analysis shows that in both nurses' (work) experience-based knowledge and population-statistical knowledge, parental competence is achieved largely through the 'natural' process of experiencing pregnant life...
October 22, 2016: Sociology of Health & Illness
Stefan Grob, Ueli Grossniklaus
Nuclear organization and higher-order chromosome structure in interphase nuclei are thought to have important effects on fundamental biological processes, including chromosome condensation, replication, and transcription. Until recently, however, nuclear organization could only be analyzed microscopically. The development of chromatin conformation capture (3C)-based techniques now allows a detailed look at chromosomal architecture from the level of individual loci to the entire genome. Here we provide a robust Hi-C protocol, allowing the analysis of nuclear organization in nuclei from different wild-type and mutant plant tissues...
2017: Methods in Molecular Biology
David J Koss, Glynn Jones, Anna Cranston, Heidi Gardner, Nicholas M Kanaan, Bettina Platt
Post-mortem investigations of human Alzheimer's disease (AD) have largely failed to provide unequivocal evidence in support of the original amyloid cascade hypothesis, which postulated deposition of β-amyloid (Aβ) aggregates to be the cause of a demented state as well as inductive to tau neurofibrillary tangles (NFTs). Conflicting evidence suggests, however, that Aβ plaques and NFTs, albeit to a lesser extent, are present in a substantial subset of non-demented individuals. Hence, a range of soluble tau and Aβ species has more recently been implicated as the disease-relevant toxic entities...
October 21, 2016: Acta Neuropathologica
Naseer Iqbal, Mukesh Kumar, Pradeep Sharma, Satya Prakash Yadav, Punit Kaur, Sujata Sharma, Tej P Singh
Dehydroquinase (3-dehydroquinate dehydratase, DHQD, EC catalyzes the conversion of dehydroquinate to dehydroshikimate. DHQD from Acinetobacter baumannii (AbDHQD) was cloned, expressed and purified to homogeneity. The binding studies showed that two compounds quinic acid and citrazinic acid bound to AbDHQD at micromolar concentrations. AbDHQD was crystallized using 30% PEG-3350, 50mM tris-HCl and 1.0M MgSO4 at PH 8.0. Crystals of AbDHQD were stabilized with 25% glycerol for data collection at 100K...
October 18, 2016: International Journal of Biological Macromolecules
Ting Hu, Qilin Huang, Kahing Wong, Hong Yang
Four polysaccharide fractions, LRP-1, LRP-2, LRP-3 and LRP-4 were extracted stepwise from Lignosus rhinocerotis sclerotia with distilled water at 25, 95, 120°C and 1.0M NaOH solution at 4°C. Their structure, molecular size and chain conformation were clarified using SEC-MALLS-RI, GC, FT-IR and UV-VIS. Furthermore, their immunomodulatory activities were evaluated by the model of cyclophosphamide (Cy)-induced immunosuppression. The LRP-1 and LRP-2 were polysaccharide-protein complexes (46-68% β-D-glucan and 27-48% protein), while LRP-3 and LRP-4 were absolutely composed of β-D-glucose...
October 18, 2016: International Journal of Biological Macromolecules
Gary C Packard
Recent reports indicate that field metabolic rates (FMRs) of mammals conform to a pattern of complex allometry in which the exponent in a simple, two-parameter power equation increases steadily as a dependent function of body mass. The reports were based, however, on indirect analyses performed on logarithmic transformations of the original data. I re-examined values for FMR and body mass for 114 species of mammal by the conventional approach to allometric analysis (to illustrate why the approach is unreliable) and by linear and nonlinear regression on untransformed variables (to illustrate the power and versatility of newer analytical methods)...
October 19, 2016: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Jeong-Eun Rah, Gwe-Ya Kim, Do Hoon Oh, Tae Hyun Kim, Jong Won Kim, Dae Yong Kim, Sung Yong Park, Dongho Shin
BACKGROUND: The purpose of this study is to evaluate the dosimetric benefits of a proton arc technique for treating tumors of the para-aortic lymph nodes (PALN). METHOD: In nine patients, a proton arc therapy (PAT) technique was compared with intensity modulated radiation therapy (IMRT) and proton beam therapy (PBT) techniques with respect to the planning target volume (PTV) and organs at risk (OAR). PTV coverage, conformity index (CI), homogeneity index (HI) and OAR doses were compared...
October 21, 2016: Radiation Oncology
Greg Hodge, Eugene Roscioli, Hubertus Jersmann, Hai B Tran, Mark Holmes, Paul N Reynolds, Sandra Hodge
BACKGROUND: Corticosteroid resistance is a major barrier to effective treatment of COPD. We have shown that the resistance is associated with decreased expression of glucocorticoid receptor (GCR) by senescent CD28nullCD8+ pro-inflammatory lymphocytes in peripheral blood of COPD patients. GCR must be bound to molecular chaperones heat shock proteins (Hsp) 70 and Hsp90 to acquire a high-affinity steroid binding conformation, and traffic to the nucleus. We hypothesized a loss of Hsp70/90 from these lymphocytes may further contribute to steroid resistance in COPD...
October 21, 2016: Respiratory Research
Toshifumi Mori, Shinji Saito
Proteins involve motions over a wide range of spatial and temporal scales. While the large conformational changes such as folding and functioning are slow and appear to occur in a highly cooperative manner, how the hierarchical dynamics over different timescales play a role during these slow transitions has been of great interest over the decades. Here we study the folding mechanism of the villin headpiece subdomain (HP35) to understand the molecular mechanism behind this prototypical fast-folding protein. The ~ 400 µs molecular dynamics (MD) trajectories obtained by Piana et al...
October 21, 2016: Journal of Physical Chemistry. B
Tadamoto Isogai, Rob van der Kammen, Onno B Bleijerveld, Soenita S Goerdayal, Elisabetta Argenzio, A F Maarten Altelaar, Metello Innocenti
Formin mDia2 is a cytoskeleton-regulatory protein that switches reversibly between a closed, auto-inhibited and an open, active conformation. Although the open conformation of mDia2 induces actin assembly thereby controlling many cellular processes, mDia2 possesses also actin-independent and conformation-insensitive scaffolding roles related to microtubules and p53, respectively. Thus, we hypothesise that mDia2 may have other unappreciated functions and regulatory modes. Here we identify and validate proteasome and Ubiquitin as mDia2-interacting partners using SILAC-based quantitative proteomics and biochemistry, respectively...
October 21, 2016: Journal of Proteome Research
Emilia Fisicaro, Carlotta Compari, Franco Bacciottini, Laura Contardi, Erika Pongiluppi, Nadia Barbero, Guido Viscardi, Pierluigi Quagliotto, Gaetano Donofrio, Marie Pierre Krafft
Biological and thermodynamic properties of a new homologous series of highly fluorinated bispyridinium cationic gemini surfactants, differing in the length of the spacer bridging the pyridinium polar heads in 1,1' position, are reported for the first time. Interestingly, gene delivery ability is closely associated with the spacer length due to a structural change of the molecule in solution. This conformation change is allowed when the spacer reaches the right length, and it is suggested by the trends of the apparent and partial molar enthalpies vs molality...
October 15, 2016: Journal of Colloid and Interface Science
Isabel P G Fernandes, Ana Maria Oliveira-Brett
Calmodulin (CaM) is an essential protein present in all eukaryote cells, ranging from vertebrates to unicellular organisms. CaM is the most important Ca(2+) signalling protein, composed of two domains, N- and C-terminal domains, linked by a flexible central α-helix, and is responsible for the regulation of numerous calcium-mediated signalling pathways. Four calcium ions bind to CaM, changing its conformation and determining how it recognizes and regulates its cellular targets. The oxidation mechanism of native and denatured CaM, at a glassy carbon electrode, was investigated using differential pulse voltammetry and electrochemical impedance spectroscopy...
October 7, 2016: Bioelectrochemistry
Kirilka Mladenova, Svetla D Petrova, Tonya D Andreeva, Veselina Moskova-Doumanova, Tanya Topouzova-Hristova, Yuri Kalvachev, Konstantin Balashev, Shomi S Bhattacharya, Christina Chakarova, Zdravko Lalchev, Jordan A Doumanov
Human bestrophin-1 (hBest1) is a transmembrane calcium-activated chloride channel protein - member of the bestrophin family of anion channels, predominantly expressed in the membrane of retinal pigment epithelium (RPE) cells. Mutations in the protein cause ocular diseases, named Bestrophinopathies. Here, we present the first Fourier transform infrared (FTIR) study of the secondary structure elements of hBest1, π/A isotherms and hysteresis, Brewster angle microscopy (BAM) and atomic force microscopy (AFM) visualization of the aggregation state of protein molecules dispersed as Langmuir and Langmuir-Blodgett films...
October 13, 2016: Colloids and Surfaces. B, Biointerfaces
Louis M Luttrell
The ability of structurally distinct ligands to "bias" G protein-coupled receptor signaling affords the opportunity to tailor efficacy to suit specific therapeutic needs. Furness et al. demonstrate that ligand structure controls not only which effectors are activated, but also the way they are activated and the kinetics of downstream signaling.
October 20, 2016: Cell
Richard A Manderville, Stacey D Wetmore
The formation of DNA adducts by the attack of intermediates derived from toxic substances at the C8 position of 2-deoxyguanosine (dG) is a common damaging event. Although the majority of studies on C8-dG adducts have focused on lesions containing a C8-N-C tether between the bulky moiety and the nucleobase, the formation of O-linked lesions with a similar tether topology and C-linked adducts involving direct C8-C connectivity have also been uncovered. Several studies have been done to try to better understand the structural impact and mutagenicity of O-linked and C-linked aryl C8-dG adducts, including lesions arising from unsubstituted and chloro substituted phenols, and the food mutagen ochratoxin A (OTA)...
October 21, 2016: Chemical Research in Toxicology
A Didier, R Dietrich, E Märtlbauer
The non-hemolytic enterotoxin complex (Nhe) is supposed to be the main virulence factor of B. cereus causing a diarrheal outcome of food poisoning. This tripartite toxin consists of the single components NheA, -B and -C all of them being necessary for maximum toxicity. In the past, research activities aiming to elucidate the mode-of-action of Nhe were mostly focused on the B- and C-component. In this study the generation of novel monoclonal antibodies (mAb) and their thorough characterization enabled the determination of key features for NheA...
2016: PloS One
Philippe Lefrançois, Beth Rockmill, Pingxing Xie, G Shirleen Roeder, Michael Snyder
During meiosis, chromosomes undergo a homology search in order to locate their homolog to form stable pairs and exchange genetic material. Early in prophase, chromosomes associate in mostly non-homologous pairs, tethered only at their centromeres. This phenomenon, conserved through higher eukaryotes, is termed centromere coupling in budding yeast. Both initiation of recombination and the presence of homologs are dispensable for centromere coupling (occurring in spo11 mutants and haploids induced to undergo meiosis) but the presence of the synaptonemal complex (SC) protein Zip1 is required...
October 2016: PLoS Genetics
Beibei Wang, Joshua Francis, Monika Sharma, Sean M Law, Alexander V Predeus, Michael Feig
Allostery is conformation regulation by propagating a signal from one site to another distal site. This study focuses on the long-range communication in DNA mismatch repair proteins MutS and its homologs where intramolecular signaling has to travel over 70 Å to couple lesion detection to ATPase activity and eventual downstream repair. Using dynamic network analysis based on extensive molecular dynamics simulations, multiple preserved communication pathways were identified that would allow such long-range signaling...
October 2016: PLoS Computational Biology
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