151 research outputs found

    Structure-based vaccine design by electron microscopy

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    Modern vaccine design relies on multiscale, interdisciplinary efforts that take advantage of innovative technologies such as in silico identification of antigens, high throughput screening of antigen immunogenicity, and gene expression profiling to predict host immune responses. In recent years, structural analysis has played an increasingly important role in vaccine development as a means to improve antigen stability, immunogenicity and large scale production. Transmission electron microscopy (TEM), and in particular cryo-TEM, is an established and powerful imaging technique applicable to many specimens, including the three-dimensional (3D) reconstruction of macromolecules and their associated complexes to high resolution. The technique is parsimonious in its material requirements and captures the specimens in their fully hydrated state, close to their native environment. The resolution of cryo-TEM reconstructions was limited to the subnanometer range until the recent development of direct electron detectors and improvements in image processing software, which has led to a so-called “resolution revolution” in the cryo-TEM field. Several protein structures have now been solved at near atomic resolution, establishing the technique as a viable alternative to X-ray analysis for high resolution structure determination. We have determined several structures with and without bound compounds at 2.9 Å – 3.6 Å resolution, which are being integrated into drug discovery and development workflows by our clients. Here we present the 2.4Å resolution structure of apoferritin determined with our Titan Krios electron microscope as an example of the cryo-TEM services available at NIS. These services are significantly enhanced with unique access by NIS to a new instrument, Spotiton, a robotic device that dispenses picoliter-volumes of sample onto a self-blotting nanowire grid as it flies past en route to vitrification. This provides several advantages over standard vitrification methods, including more automated and reproducible preparation of specimens and reducing the deleterious effects of particles interacting with the air-water interface. While high resolution 3D structure determination by cryo-TEM is at the forefront of structural biology, averages of 2D projection images at moderate resolution in negative stain or vitreous ice can also provide a wealth of information that may be difficult to obtain using other methods. This is illustrated in a number of case studies, including (1) mapping of neutralizing epitopes on the CMV pentameric glycoprotein complex; (2) mapping of neutralizing epitopes on the HIV-1 envelope glycoprotein trimer; (3) assessment of structure and conformational stability of pre- and post-fusion RSV-F protein; (4) characterization of novel adjuvants and protein delivery systems. In summary, both the moderate resolution TEM and high resolution cryo-TEM methods are well suited to extensively characterize antigen structure-function relationships, some of which may be refractory to other experimental methods

    Planning for the Lifecycle Management and Long-Term Preservation of Research Data: A Federated Approach

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    Outcomes of the grant are archived here.The “data deluge” is a recent but increasingly well-understood phenomenon of scientific and social inquiry. Large-scale research instruments extend our observational power by many orders of magnitude but at the same time generate massive amounts of data. Researchers work feverishly to document and preserve changing or disappearing habitats, cultures, languages, and artifacts resulting in volumes of media in various formats. New software tools mine a growing universe of historical and modern texts and connect the dots in our semantic environment. Libraries, archives, and museums undertake digitization programs creating broad access to unique cultural heritage resources for research. Global-scale research collaborations with hundreds or thousands of participants, drive the creation of massive amounts of data, most of which cannot be recreated if lost. The University of Kansas (KU) Libraries in collaboration with two partners, the Greater Western Library Alliance (GWLA) and the Great Plains Network (GPN), received an IMLS National Leadership Grant designed to leverage collective strengths and create a proposal for a scalable and federated approach to the lifecycle management of research data based on the needs of GPN and GWLA member institutions.Institute for Museum and Library Services LG-51-12-0695-1

    Identification of a Wide, Low-Mass Multiple System Containing the Brown Dwarf 2MASS J0850359+105716

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    We report our discovery of NLTT 20346 as an M5+M6 companion system to the tight binary (or triple) L dwarf 2MASS J0850359+105716. This nearby (~31 pc), widely separated (~7700 AU) quadruple system was identified through a cross-match of proper motion catalogs. Follow-up imaging and spectroscopy of NLTT 20346 revealed it to be a magnetically active M5+M6 binary with components separated by ~2" (50-80 AU). Optical spectroscopy of the components show only moderate Halpha emission corresponding to a statistical age of ~5 - 7 Gyr for both M dwarfs. However NLTT 20346 is associated with the XMM-Newton source J085018.9+105644, and based on X-ray activity the age of NLTT 20346 is between 250-450 Myr. Strong Li absorption in the optical spectrum of 2MASS J0850+1057 indicates an upper age limit of 0.8 - 1.5 Gyr favoring the younger age for the primary. Using evolutionary models in combination with an adopted system age of 0.25-1.5 Gyr indicates a total mass for 2MASS J0850+1057 of 0.07+/-0.02 Msun if it is a binary. NLTT 20346/2MASS J0850+1057 joins a growing list of hierarchical systems containing brown dwarf binaries and is among the lowest binding energy associations found in the field. Formation simulations via gravitational fragmentation of massive extended disks have successfully produced a specific analog to this system.Comment: 13 pages, accepted for publication to A

    The correlation between reading and mathematics ability at age twelve has a substantial genetic component

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    Dissecting how genetic and environmental influences impact on learning is helpful for maximizing numeracy and literacy. Here we show, using twin and genome-wide analysis, that there is a substantial genetic component to children’s ability in reading and mathematics, and estimate that around one half of the observed correlation in these traits is due to shared genetic effects (so-called Generalist Genes). Thus, our results highlight the potential role of the learning environment in contributing to differences in a child’s cognitive abilities at age twelve

    A Multilevel Mhealth intervention Boosts adherence to Hydroxyurea in individuals With Sickle Cell Disease

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    Hydroxyurea reduces sickle cell disease (SCD) complications, but medication adherence is low. We tested 2 mobile health (mHealth) interventions targeting determinants of low adherence among patients (InCharge Health) and low prescribing among providers (HU toolbox) in a multi-center, non-randomized trial of individuals with SCD ages 15-45. We compared the percentage of days covered (PDC), labs, healthcare utilization, and self-reported pain over 24 weeks of intervention and 12 weeks post-study with a 24-week preintervention interval. We enrolled 293 patients (51% male; median age 27.5 years, 86.8% HbSS/HbSÎČ0-thalassemia). The mean change in PDC among 235 evaluable subjects increased (39.7% to 56.0%; P \u3c 0.001) and sustained (39.7% to 51.4%, P \u3c 0.001). Mean HbF increased (10.95% to 12.78%; P = 0.03). Self-reported pain frequency reduced (3.54 to 3.35 events/year; P = 0.041). InCharge Health was used ≄1 day by 199 of 235 participants (84.7% implementation; median usage: 17% study days; IQR: 4.8-45.8%). For individuals with ≄1 baseline admission for pain, admissions per 24 weeks declined from baseline through 24 weeks (1.97 to 1.48 events/patient, P = 0.0045) and weeks 25-36 (1.25 events/patient, P = 0.0015). PDC increased with app use (P \u3c 0.001), with the greatest effect in those with private insurance (P = 0.0078), older subjects (P = 0.033), and those with lower pain interference (P = 0.0012). Of the 89 providers (49 hematologists, 36 advanced care providers, 4 unreported), only 11.2% used HU toolbox ≄1/month on average. This use did not affect change in PDC. Tailoring mHealth solutions to address barriers to hydroxyurea adherence can potentially improve adherence and provide clinical benefits. A definitive randomized study is warranted. This trial was registered at www.clinicaltrials.gov as #NCT04080167

    Crystal structure of rhodopsin bound to arrestin by femtosecond X-ray laser.

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    G-protein-coupled receptors (GPCRs) signal primarily through G proteins or arrestins. Arrestin binding to GPCRs blocks G protein interaction and redirects signalling to numerous G-protein-independent pathways. Here we report the crystal structure of a constitutively active form of human rhodopsin bound to a pre-activated form of the mouse visual arrestin, determined by serial femtosecond X-ray laser crystallography. Together with extensive biochemical and mutagenesis data, the structure reveals an overall architecture of the rhodopsin-arrestin assembly in which rhodopsin uses distinct structural elements, including transmembrane helix 7 and helix 8, to recruit arrestin. Correspondingly, arrestin adopts the pre-activated conformation, with a ∌20° rotation between the amino and carboxy domains, which opens up a cleft in arrestin to accommodate a short helix formed by the second intracellular loop of rhodopsin. This structure provides a basis for understanding GPCR-mediated arrestin-biased signalling and demonstrates the power of X-ray lasers for advancing the frontiers of structural biology

    A mouse model with a frameshift mutation in the nuclear factor I/X (NFIX) gene has phenotypic features of Marshall-Smith syndrome

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    The nuclear factor I/X (NFIX) gene encodes a ubiquitously expressed transcription factor whose mutations lead to two allelic disorders characterized by developmental, skeletal, and neural abnormalities, namely, Malan syndrome (MAL) and Marshall–Smith syndrome (MSS). NFIX mutations associated with MAL mainly cluster in exon 2 and are cleared by nonsense-mediated decay (NMD) leading to NFIX haploinsufficiency, whereas NFIX mutations associated with MSS are clustered in exons 6–10 and escape NMD and result in the production of dominant-negative mutant NFIX proteins. Thus, different NFIX mutations have distinct consequences on NFIX expression. To elucidate the in vivo effects of MSS-associated NFIX exon 7 mutations, we used CRISPR-Cas9 to generate mouse models with exon 7 deletions that comprised: a frameshift deletion of two nucleotides (Nfix Del2); in-frame deletion of 24 nucleotides (Nfix Del24); and deletion of 140 nucleotides (Nfix Del140). Nfix+/Del2, Nfix+/Del24, Nfix+/Del140, NfixDel24/Del24, and NfixDel140/Del140 mice were viable, normal, and fertile, with no skeletal abnormalities, but NfixDel2/Del2 mice had significantly reduced viability (p Nfix Del2 was not cleared by NMD, and NfixDel2/Del2 mice, when compared to Nfix+/+ and Nfix+/Del2 mice, had: growth retardation; short stature with kyphosis; reduced skull length; marked porosity of the vertebrae with decreased vertebral and femoral bone mineral content; and reduced caudal vertebrae height and femur length. Plasma biochemistry analysis revealed NfixDel2/Del2 mice to have increased total alkaline phosphatase activity but decreased C-terminal telopeptide and procollagen-type-1-N-terminal propeptide concentrations compared to Nfix+/+ and Nfix+/Del2 mice. NfixDel2/Del2 mice were also found to have enlarged cerebral cortices and ventricular areas but smaller dentate gyrus compared to Nfix+/+ mice. Thus, NfixDel2/Del2 mice provide a model for studying the in vivo effects of NFIX mutants that escape NMD and result in developmental abnormalities of the skeletal and neural tissues that are associated with MSS

    New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk.

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    Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes
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