75 research outputs found

    Reconstruction and validation of entire virus model with complete genome from mixed resolution cryo-EM density

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    It is very difficult to reconstruct computationally a large biomolecular complex in its biological entirety from experimental data. The resulting atomistic model should not contain gaps structurally and it should yield stable dynamics. We, for the first time, reconstruct from published incomplete cryo-EM density a complete MS2 virus at atomistic resolution, that is, the capsid with the genome, and validate the result by all-atom Molecular Dynamics with explicit water. The available experimental data includes a high resolution protein capsid and an inhomogeneously resolved genome map. For the genomic RNA, apart from 16 hairpins with atomistic resolution, the strands near the capsid’s inner surface were resolved up to the nucleic backbone level, and the innermost density was completely unresolved. As a result, only 242 nucleotides (out of 3569) were positioned, while only a fragmented backbone was outlined for the rest of the genome, making a detailed model reconstruction necessary. For model reconstruction, in addition to the available atomistic structure information, we extensively used the predicted secondary structure of the genome (base pairing). The technique was based on semi-automatic building of relatively large strands of RNA with subsequent manual positioning over the traced backbone. The entire virus structure (capsid+genome) was validated by a Molecular Dynamics run in physiological solution with ions at standard conditions confirming the stability of the model

    An increase in plasma adiponectin multimeric complexes follows hypocaloric diet-induced weight loss in obese and overweight premenopausal women. Clin Sci (Lond

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    A B S T R A C T Adiponectin is involved in the regulation of glucose and fatty acid metabolism, influences wholebody insulin sensitivity and protects arterial walls against the development of atherosclerosis. Plasma adiponectin is decreased in obese, insulin-resistant and Type 2 diabetic patients. Adiponectin circulates in plasma as high-, medium-and low-molecular-weight ('mass') forms (HMW, MMW and LMW respectively). The HMW form is believed to be closely associated with insulin sensitivity. The aim of the present study was to investigate whether diet-induced changes in body weight and insulin sensitivity were associated with changes in the quantity of adiponectin multimeric complexes. A total of 20 overweight or obese women (age, 39.4 + − 9.5 years; body mass index, 32.2 + − 6.4 kg/m 2 ) underwent 12 weeks of low caloric diet (600 kcal/day less than energy requirements; where 1 kcal ≈ 4.184 kJ). Plasma samples were drawn before and after the study for biochemical analysis and Western blot detection of adiponectin multimeric complexes. The hypocaloric diet resulted in a weight reduction (89.8 + − 16.4 kg compared with 83.1 + − 15.6 kg; P < 0.001) and an improvement in whole-body insulin sensitivity, as measured by HOMA (homoeostasis model assessment index; 1.9 + − 0.8 compared with 1.5 + − 0.7; P = 0.013). Increases in the quantities of the HMW, MMW and LMW forms by 5.5, 8.5 and 18.1 % respectively, were observed (P < 0.05 for all of the forms). Total plasma adiponectin was increased by 36 % with borderline significance (P = 0.08). No correlations between changes in adiponectin complexes and changes in indices of insulin sensitivity were observed. In conclusion, diet-induced weight loss improved insulin sensitivity as well as increased the amount of HMW, MMW and LMW adiponectin complexes in plasma

    Association of novel monomethine cyanine dyes with bacteriophage MS2:A fluorescence study

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    Novel monomethine cyanine dyes Cl-YO, F-YO, Cl-YO-Et, Cl-YO-Bu, and YO-Pent were evaluated as agents to detect and characterise a small virus, the MS2 bacteriophage, using the dye and virus intrinsic fluorescence, kinetic and thermal properties, chemical denaturation, and molecular docking and quantum chemistry modelling. The examined compounds demonstrated enhanced fluorescence responses and high affinities (~1 μM−1) for the intact bacteriophage at physiological ionic strength. The linear Scatchard plots revealed the existence of one binding mode for most dyes. Strong evidence that the cyanines bind to the bacteriophage external surface were obtained, although the possibility of the dye penetration through the virus shell and subsequent complexation with the viral RNA was also tested. The main arguments in favour of the former were that i) the fluorescence of the MS2-bound fluorophores decreased under the influence of protein denaturants, urea and guanidine hydrochloride; ii) the fluorescence responses of the dyes to MS2 and bovine serum albumin were similar; and (iii) one order of magnitude higher sensitivity of the dyes to the yeast RNA was found. Simple docking studies suggested that one cyanine molecule is trapped in a cleft formed by three proteins composing the virus shell. Significant role of electrostatic forces in the stabilisation of the dye-MS2 complexes at low ionic strength (10 mM) was demonstrated, while the influence of steric, hydrophobic, and van-der-Waals interactions was expected to increase at physiological ionic strength. The spectral properties of the novel cyanine dyes compared to other fluorophores demonstrated higher sensitivity of the cyanines to MS2, rendering them promising agents for the investigation of the changes in the virus structure under the influence of heat (Cl-YO-Et, Cl-YO-Bu), denaturants (Cl-YO, F-YO), and ionic strength (all the compounds)

    Genetic polymorphisms and weight loss in obesity: A randomised trial of hypo-energetic high-versus low-fat diets

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    OBJECTIVES: To study if genes with common single nucleotide polymorphisms (SNPs) associated with obesity-related phenotypes influence weight loss (WL) in obese individuals treated by a hypo-energetic low-fat or high-fat diet. DESIGN: Randomised, parallel, two-arm, open-label multi-centre trial. SETTING: Eight clinical centres in seven European countries. PARTICIPANTS: 771 obese adult individuals. INTERVENTIONS: 10-wk dietary intervention to hypo-energetic (-600 kcal/d) diets with a targeted fat energy of 20%-25% or 40%-45%, completed in 648 participants. OUTCOME MEASURES: WL during the 10 wk in relation to genotypes of 42 SNPs in 26 candidate genes, probably associated with hypothalamic regulation of appetite, efficiency of energy expenditure, regulation of adipocyte differentiation and function, lipid and glucose metabolism, or production of adipocytokines, determined in 642 participants. RESULTS: Compared with the noncarriers of each of the SNPs, and after adjusting for gender, age, baseline weight and centre, heterozygotes showed WL differences that ranged from -0.6 to 0.8 kg, and homozygotes, from -0.7 to 3.1 kg. Genotype-dependent additional WL on low-fat diet ranged from 1.9 to -1.6 kg in heterozygotes, and from 3.8 kg to -2.1 kg in homozygotes relative to the noncarriers. Considering the multiple testing conducted, none of the associations was statistically significant. CONCLUSIONS: Polymorphisms in a panel of obesity-related candidate genes play a minor role, if any, in modulating weight changes induced by a moderate hypo-energetic low-fat or high-fat diet

    Complete Virion Simulated: All-Atom Model of an MS2 Bacteriophage with Native Genome

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    For the first time, a complete all-atom molecular dynamics (MD) model of a virus, bacteriophage MS2, in its entirety, including a protein outer shell, native genomic RNA with necessary divalent ions, and surrounding explicit aqueous solution with ions at physiological concentration, was built. The model is based on an experimentally measured cryo-EM structure, which was substantially augmented by reconstructing missing or low-resolution parts of the measured density (where the atomistic structure cannot be fit unambiguously). The model was tested by a quarter of a microsecond MD run, and various biophysical characteristics are obtained and analyzed. The developed methodology of building the model can be used for reconstructing other large biomolecular structures when experimental data are fragmented and/or of varying resolution, while the model itself can be used for studying the biology of MS2, including the dynamics of its interaction with the host bacteria

    Managing Disruptions in Production with Machine Learning

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    Changing customer demands lead to increasing product varieties and decreasing delivery times, which in turn pose great challenges for production companies. Combined with high market volatility, they lead to increasingly complex and diverse production processes. Thus, the susceptibility to disruptions in manufacturing rises, turning the task of Production Planning and Control (PPC) into a complex, dynamic and multidimensional problem. Addressing PPC challenges such as disruption management in an efficient and timely manner requires a high level of manual human intervention. In times of digitization and Industry 4.0, companies strive to find ways to guide their workers in this process of disruption management or automate it to eliminate human intervention altogether. This paper presents one possible application of Machine Learning (ML) in disruption management on a real-life use case in mixed model continuous production, specifically in the final assembly. The aim is to ensure high-quality online decision support for PPC tasks. This paper will therefore discuss the use of ML to anticipate production disruptions, solutions to efficiently highlight and convey the relevant information, as well as the generation of possible reaction strategies. Additionally, the necessary preparatory work and fundamentals are covered in the discussion, providing guidelines for production companies towards consistent and efficient disruption management
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