Profile Of A Nation

Behind every face lies a story. Behind the profile of Abraham Lincoln dwelled the soulstirring drama of a fledging nation-its tribulations, its triumphs. Every stroke of the artist in painting the President depicted character, hope, life

Pathogenic Variants in Fucokinase Cause a Congenital Disorder of Glycosylation

FUK encodes fucokinase, the only enzyme capable of converting L-fucose to fucose-1-phosphate, which will ultimately be used for synthesizing GDP-fucose, the donor substrate for all fucosyltransferases. Although it is essential for fucose salvage, this pathway is thought to make only a minor contribution to the total amount of GDP-fucose. A second pathway, the major de novo pathway, involves conversion of GDP-mannose to GDP-fucose. Here we describe two unrelated individuals who have pathogenic variants in FUK and who presented with severe developmental delays, encephalopathy, intractable seizures, and hypotonia. The first individual was compound heterozygous for c.667T>C (p.Ser223Pro) and c.2047C>T (p.Arg683Cys), and the second individual was homozygous for c.2980A>C (p.Lys994Gln). Skin fibroblasts from the first individual confirmed the variants as loss of function and showed significant decreases in total GDP-[3H] fucose and [3H] fucose-1-phosphate. There was also a decrease in the incorporation of [5,6-3H]-fucose into fucosylated glycoproteins. Lys994 has previously been shown to be an important site for ubiquitin conjugation. Here, we show that loss-of-function variants in FUK cause a congenital glycosylation disorder characterized by a defective fucose-salvage pathway

Strain-stiffening gels based on latent crosslinking

Gels are an increasingly important class of soft materials with applications ranging from regenerative medicine to commodity materials. A major drawback of gels is their relative mechanical weakness, which worsens further under strain. We report a new class of responsive gels with latent crosslinking moieties that exhibit strain-stiffening behavior. This property results from the lability of disulfides, initially isolated in a protected state, then activated to crosslink on-demand. The active thiol groups are induced to form inter-chain crosslinks when subjected to mechanical compression, resulting in a gel that strengthens under strain. Molecular shielding design elements regulate the strain-sensitivity and spontaneous crosslinking tendencies of the polymer network. These strain-responsive gels represent a rational design of new advanced materials with on-demand stiffening properties with potential applications in elastomers, adhesives, foams, films, and fibers

Substance Use and Mild Traumatic Brain Injury Risk Reduction and Prevention: A Novel Model for Treatment

Traumatic brain injury (TBI) and substance use disorders (SUDs) frequently co-occur. Individuals with histories of alcohol or other drug use are at greater risk for sustaining TBI, and individuals with TBI frequently misuse substances before and after injury. Further, a growing body of literature supports the relationship between comorbid histories of mild TBI (mTBI) and SUDs and negative outcomes. Alcohol and other drug use are strongly associated with risk taking. Disinhibition, impaired executive function, and/or impulsivity as a result of mTBI also contribute to an individual's proclivity towards risk-taking. Risk-taking behavior may therefore, be a direct result of SUD and/or history of mTBI, and risky behaviors may predispose individuals for subsequent injury or continued use of substances. Based on these findings, evaluation of risk-taking behavior associated with the co-occurrence of SUD and mTBI should be a standard clinical practice. Interventions aimed at reducing risky behavior among members of this population may assist in decreasing negative outcomes. A novel intervention (Substance Use and Traumatic Brain Injury Risk Reduction and Prevention (STRRP)) for reducing and preventing risky behaviors among individuals with co-occurring mTBI and SUD is presented. Areas for further research are discussed

Nanopercolation

We investigate through direct molecular mechanics calculations the geometrical properties of hydrocarbon mantles subjected to percolation disorder. We show that the structures of mantles generated at the critical percolation point have a fractal dimension $d_{f} \approx 2.5$. In addition, the solvent access surface $A_{s}$ and volume $V_{s}$ of these molecules follow power-law behavior, $A_{s} \sim L^{\alpha_A}$ and $V_{s} \sim L^{\alpha_V}$, where $L$ is the system size, and with both critical exponents $\alpha_A$ and $\alpha_V$ being significantly dependent on the radius of the accessing probing molecule, $r_{p}$. Our results from extensive simulations with two distinct microscopic topologies (i.e., square and honeycomb) indicate the consistency of the statistical analysis and confirm the self-similar characteristic of the percolating hydrocarbons. Due to their highly branched topology, some of the potential applications for this new class of disordered molecules include drug delivery, catalysis, and supramolecular structures.Comment: 4 pages, 5 figure

2-Pyrrolidinone and Succinimide as Clinical Screening Biomarkers for GABA-Transaminase Deficiency: Anti-seizure Medications Impact Accurate Diagnosis

Broad-scale untargeted biochemical phenotyping is a technology that supplements widely accepted assays, such as organic acid, amino acid, and acylcarnitine analyses typically utilized for the diagnosis of inborn errors of metabolism. In this study, we investigate the analyte changes associated with 4-aminobutyrate aminotransferase (ABAT, GABA transaminase) deficiency and treatments that affect GABA metabolism. GABA-transaminase deficiency is a rare neurodevelopmental and neurometabolic disorder caused by mutations in ABAT and resulting in accumulation of GABA in the cerebrospinal fluid (CSF). For that reason, measurement of GABA in CSF is currently the primary approach to diagnosis. GABA-transaminase deficiency results in severe developmental delay with intellectual disability, seizures, and movement disorder, and is often associated with death in childhood. Using an untargeted metabolomics platform, we analyzed EDTA plasma, urine, and CSF specimens from four individuals with GABA-transaminase deficiency to identify biomarkers by comparing the biochemical profile of individual patient samples to a pediatric-centric population cohort. Metabolomic analyses of over 1,000 clinical plasma samples revealed a rich source of biochemical information. Three out of four patients showed significantly elevated levels of the molecule 2-pyrrolidinone (Z-score ≥ 2) in plasma, and whole exome sequencing revealed variants of uncertain significance in ABAT. Additionally, these same patients also had elevated levels of succinimide or its ring-opened form, succinamic acid, in plasma, urine, and CSF and/or homocarnosine in urine and CSF. In the analysis of clinical EDTA plasma samples, the levels of succinamic acid and 2-pyrrolidinone showed a high level of correlation (R = 0.72), indicating impairment in GABA metabolism and further supporting the association with GABA-transaminase deficiency and the pathogenicity of the ABAT variants. Further analysis of metabolomic data across our patient population revealed the association of elevated levels of 2-pyrrolidinone with administration of vigabatrin, a commonly used anti-seizure medication and a known inhibitor of GABA-transaminase. These data indicate that anti-seizure medications may alter the biochemical and metabolomic data, potentially impacting the interpretation and diagnosis for the patient. Further, these data demonstrate the power of combining broad scale genotyping and phenotyping technologies to diagnose inherited neurometabolic disorders and support the use of metabolic phenotyping of plasma to screen for GABA-transaminase deficiency

Interatomic potentials for atomistic simulations of the Ti-Al system

Semi-empirical interatomic potentials have been developed for Al, alpha-Ti, and gamma-TiAl within the embedded atomic method (EAM) by fitting to a large database of experimental as well as ab-initio data. The ab-initio calculations were performed by the linear augmented plane wave (LAPW) method within the density functional theory to obtain the equations of state for a number of crystal structures of the Ti-Al system. Some of the calculated LAPW energies were used for fitting the potentials while others for examining their quality. The potentials correctly predict the equilibrium crystal structures of the phases and accurately reproduce their basic lattice properties. The potentials are applied to calculate the energies of point defects, surfaces, planar faults in the equilibrium structures. Unlike earlier EAM potentials for the Ti-Al system, the proposed potentials provide reasonable description of the lattice thermal expansion, demonstrating their usefulness in the molecular dynamics or Monte Carlo studies at high temperatures. The energy along the tetragonal deformation path (Bain transformation) in gamma-TiAl calculated with the EAM potential is in a fairly good agreement with LAPW calculations. Equilibrium point defect concentrations in gamma-TiAl are studied using the EAM potential. It is found that antisite defects strongly dominate over vacancies at all compositions around stoichiometry, indicating that gamm-TiAl is an antisite disorder compound in agreement with experimental data.Comment: 46 pages, 6 figures (Physical Review B, in press

Common data elements for clinical research in mitochondrial disease: a National Institute for Neurological Disorders and Stroke project

Objectives The common data elements (CDE) project was developed by the National Institute of Neurological Disorders and Stroke (NINDS) to provide clinical researchers with tools to improve data quality and allow for harmonization of data collected in different research studies. CDEs have been created for several neurological diseases; the aim of this project was to develop CDEs specifically curated for mitochondrial disease (Mito) to enhance clinical research. Methods Nine working groups (WGs), composed of international mitochondrial disease experts, provided recommendations for Mito clinical research. They initially reviewed existing NINDS CDEs and instruments, and developed new data elements or instruments when needed. Recommendations were organized, internally reviewed by the Mito WGs, and posted online for external public comment for a period of eight weeks. The final version was again reviewed by all WGs and the NINDS CDE team prior to posting for public use

ERK2 phosphorylation of serine 77 regulates Bmf pro-apoptotic activity

B-cell lymphoma 2 (Bcl-2) homology 3 (BH3)-only proteins represent a class of pro-apoptotic factors that neutralize pro-survival Bcl-2 proteins, and, in some cases, directly activate Bax. The mechanisms of control and the role of BH3-only proteins, such as Bcl-2 like protein 11 extra large and Bad are well studied. By contrast, relatively little is known about the regulation and role of Bcl-2 modifying factor (Bmf). The B-RAF oncogene is mutated in ∼8% of human tumors. We have previously shown that Bmf is upregulated at the transcript level and is required for apoptosis induced by targeting B-RAF signaling in tumor cells harboring mutant B-RAF. In this study, we show that Bmf is regulated at the post-translational level by mutant B-RAF-MEK-ERK2 signaling. Extracellular signal-regulated kinase (ERK2) directly phosphorylates Bmf on serine 74 and serine 77 residues with serine 77 being the predominant site. In addition, serine 77 phosphorylation reduces Bmf pro-apoptotic activity likely through a mechanism independent of altering Bmf localization to the mitochondria and/or interactions with dynein light chain 2 and the pro-survival proteins, B-cell lymphoma extra large, Bcl-2 and Mcl-1. These data identify a novel mode of regulation in Bmf that modulates its pro-apoptotic activity in mutant B-RAF tumor cells