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1.
Angew Chem Int Ed Engl ; : e202403189, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38701048

RESUMO

Understanding how reaction heterogeneity impacts cathode materials during Li-ion battery (LIB) electrochemical cycling is pivotal for unraveling their electrochemical performance. Yet, experimentally verifying these reactions has proven to be a challenge. To address this, we employed scanning µ-XRD computed tomography to scrutinize Ni-rich layered LiNi0.6Co0.2Mn0.2O2 (NCM622) and Li-rich layered Li[Li0.2Ni0.2Mn0.6]O2 (LLNMO). By harnessing machine learning (ML) techniques, we scrutinized an extensive dataset of µ-XRD patterns, about 100,000 patterns per slice, to unveil the spatial distribution of crystalline structure and microstrain. Our experimental findings unequivocally reveal the distinct behavior of these materials. NCM622 exhibits structural degradation and lattice strain intricately linked to the size of secondary particles. Smaller particles and the surface of larger particles in contact with the carbon/binder matrix experience intensified structural fatigue after long-term cycling. Conversely, both the surface and bulk of LLNMO particles endure severe strain-induced structural degradation during high-voltage cycling, resulting in significant voltage decay and capacity fade. This work holds the potential to fine-tune the microstructure of advanced layered materials and manipulate composite electrode construction in order to enhance the performance of LIBs and beyond.

2.
Biochemistry ; 62(16): 2442-2449, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37526986

RESUMO

The interplay between active-site chemistry and functionally relevant enzyme motions can provide useful insights into selective enzyme modulation. Modulation of the hypoxia-sensing function of factor-inhibiting-HIF-1 (FIH) enzyme is a potential therapeutic strategy in disease states such as ischemia and cancer. The hypoxia-sensing function of FIH relies in major part on the tight coupling of the first half of the catalytic mechanism which involves O2 activation and eventual succinate production to the second half which involves HIF-1α/CTAD substrate hydroxylation. In this study, we demonstrate the role of a loop hinge domain in FIH (FIH102-118) called the 100s loop in maintaining this particular tight coupling. Molecular dynamics patterns from Gaussian Network Model (iGNM) database analysis of FIH identified the 100s loop as one dynamic domain containing a hinge residue (Tyr102) with a potential substrate positioning role. Enzymological and biophysical studies of the 100s loop point mutants revealed altered enzyme kinetics with the exception of the conservative FIH mutant Y102F, which suggests a sterics-related role for this residue. Removal of the bulk of Tyr102 (Y102A) resulted in succinate production, autohydroxylation, and an O2 binding environment comparable to wild-type FIH. However, the HIF-1α/CTAD substrate hydroxylation of this mutant was significantly reduced which implies that (1) the FIH loop hinge residue Tyr102 does not affect O2 activation, (2) the stacking steric interaction of Tyr102 is important in substrate positioning for productive hydroxylation, and (3) Tyr102 is important for the synchronization of O2 activation and substrate hydroxylation.

3.
Development ; 147(21)2020 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-32467233

RESUMO

Nonsyndromic clefts of the lip and palate are common birth defects resulting from gene-gene and gene-environment interactions. Mutations in human MSX1 have been linked to orofacial clefting and we show here that Msx1 deficiency causes a growth defect of the medial nasal process (Mnp) in mouse embryos. Although this defect alone does not disrupt lip formation, Msx1-deficient embryos develop a cleft lip when the mother is transiently exposed to reduced oxygen levels or to phenytoin, a drug known to cause embryonic hypoxia. In the absence of interacting environmental factors, the Mnp growth defect caused by Msx1 deficiency is modified by a Pax9-dependent 'morphogenetic regulation', which modulates Mnp shape, rescues lip formation and involves a localized abrogation of Bmp4-mediated repression of Pax9 Analyses of GWAS data revealed a genome-wide significant association of a Gene Ontology morphogenesis term (including assigned roles for MSX1, MSX2, PAX9, BMP4 and GREM1) specifically for nonsyndromic cleft lip with cleft palate. Our data indicate that MSX1 mutations could increase the risk for cleft lip formation by interacting with an impaired morphogenetic regulation that adjusts Mnp shape, or through interactions that inhibit Mnp growth.


Assuntos
Hipóxia/embriologia , Hipóxia/metabolismo , Lábio/embriologia , Fator de Transcrição MSX1/deficiência , Morfogênese , Animais , Proteína Morfogenética Óssea 4/metabolismo , Fenda Labial/embriologia , Fenda Labial/genética , Fenda Labial/patologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Genoma , Proteínas de Homeodomínio/metabolismo , Humanos , Hipóxia/genética , Fator de Transcrição MSX1/genética , Fator de Transcrição MSX1/metabolismo , Mesoderma/embriologia , Mesoderma/metabolismo , Camundongos Endogâmicos C57BL , Morfogênese/genética , Mutação/genética , Nariz/embriologia , Oxigênio/metabolismo , Fator de Transcrição PAX9/metabolismo , Fenitoína , Respiração , Regulação para Cima/genética
4.
Small ; 19(44): e2304102, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37394707

RESUMO

Herein, the electrochemical properties and reaction mechanism of Li3-2 x Cax V2 (PO4 )3 /C (x = 0, 0.5, 1, and 1.5) as negative electrode materials for sodium-ion/potassium-ion batteries (SIBs/PIBs) are investigated. All samples undergo a mixed contribution of diffusion-controlled and pseudocapacitive-type processes in SIBs and PIBs via Trasatti Differentiation Method, while the latter increases with Ca content increase. Among them, Li3 V2 (PO4 )3 /C exhibits the highest reversible capacity in SIBs and PIBs, while Ca1.5 V2 (PO4 )3 /C shows the best rate performance with a capacity retention of 46% at 20 C in SIBs and 47% at 10 C in PIBs. This study demonstrates that the specific capacity of this type of material in SIBs and PIBs does not increase with the Ca-content as previously observed in lithium-ion system, but the stability and performance at a high C-rate can be improved by replacing Li+ with Ca2+ . This indicates that the insertion of different monovalent cations (Na+ /K+ ) can strongly influence the redox reaction and structure evolution of the host materials, due to the larger ion size of Na+ and K+ and their different kinetic properties with respect to Li+ . Furthermore, the working mechanism of both LVP/C and Ca1.5 V2 (PO4 )3 /C in SIBs are elucidated via in operando synchrotron diffraction and in operando X-ray absorption spectroscopy.

5.
Angew Chem Int Ed Engl ; 62(12): e202214880, 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36545843

RESUMO

Ni-rich layered oxides are one of the most attractive cathode materials in high-energy-density lithium-ion batteries, their degradation mechanisms are still not completely elucidated. Herein, we report a strong dependence of degradation pathways on the long-range cationic disordering of Co-free Ni-rich Li1-m (Ni0.94 Al0.06 )1+m O2 (NA). Interestingly, a disordered layered phase with lattice mismatch can be easily formed in the near-surface region of NA particles with very low cation disorder (NA-LCD, m≤0.06) over electrochemical cycling, while the layered structure is basically maintained in the core of particles forming a "core-shell" structure. Such surface reconstruction triggers a rapid capacity decay during the first 100 cycles between 2.7 and 4.3 V at 1 C or 3 C. On the contrary, the local lattice distortions are gradually accumulated throughout the whole NA particles with higher degrees of cation disorder (NA-HCD, 0.06≤m≤0.15) that lead to a slow capacity decay upon cycling.

6.
BMC Genomics ; 23(1): 747, 2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36357860

RESUMO

BACKGROUND: Understanding the micro--evolutionary response of populations to demographic declines is a major goal in evolutionary and conservation biology. In small populations, genetic drift can lead to an accumulation of deleterious mutations, which will increase the risk of extinction. However, demographic recovery can still occur after extreme declines, suggesting that natural selection may purge deleterious mutations, even in extremely small populations. The Chatham Island black robin (Petroica traversi) is arguably the most inbred bird species in the world. It avoided imminent extinction in the early 1980s and after a remarkable recovery from a single pair, a second population was established and the two extant populations have evolved in complete isolation since then. Here, we analysed 52 modern and historical genomes to examine the genomic consequences of this extreme bottleneck and the subsequent translocation. RESULTS: We found evidence for two-fold decline in heterozygosity and three- to four-fold increase in inbreeding in modern genomes. Moreover, there was partial support for temporal reduction in total load for detrimental variation. In contrast, compared to historical genomes, modern genomes showed a significantly higher realised load, reflecting the temporal increase in inbreeding. Furthermore, the translocation induced only small changes in the frequency of deleterious alleles, with the majority of detrimental variation being shared between the two populations. CONCLUSION: Our results highlight the dynamics of mutational load in a species that recovered from the brink of extinction, and show rather limited temporal changes in mutational load. We hypothesise that ancestral purging may have been facilitated by population fragmentation and isolation on several islands for thousands of generations and may have already reduced much of the highly deleterious load well before human arrival and introduction of pests to the archipelago. The majority of fixed deleterious variation was shared between the modern populations, but translocation of individuals with low mutational load could possibly mitigate further fixation of high-frequency deleterious variation.


Assuntos
Deriva Genética , Endogamia , Humanos , Seleção Genética , Alelos , Genômica , Variação Genética
7.
Biochemistry ; 60(44): 3315-3322, 2021 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-34714626

RESUMO

Cellular hypoxia plays a crucial role in tissue development and adaptation to pO2. Central to cellular oxygen sensing is factor-inhibiting HIF-1α (FIH), an α-ketoglutarate (αKG)/non-heme iron(II)-dependent dioxygenase that hydroxylates a specific asparagine residue of hypoxia inducible factor-1α (HIF-1α). The high KM(O2) and rate-limiting decarboxylation step upon O2 activation are key features of the enzyme that classify it as an oxygen sensor and set it apart from other αKG/Fe(II)-dependent dioxygenases. Although the chemical intermediates following decarboxylation are presumed to follow the consensus mechanism of other αKG/Fe(II)-dependent dioxygenases, experiments have not previously demonstrated these canonical steps in FIH. In this work, a deuterated peptide substrate was used as a mechanistic probe for the canonical hydrogen atom transfer (HAT). Our data show a large kinetic isotope effect (KIE) in steady-state kinetics (Dkcat = 10 ± 1), revealing that the HAT occurs and is partially rate limiting on kcat. Kinetic studies showed that the deuterated peptide led FIH to uncouple O2 activation and provided the opportunity to spectroscopically observe the ferryl intermediate. This enzyme uncoupling was used as an internal competition with respect to the fate of the ferryl intermediate, demonstrating a large observed KIE on the uncoupling (Dk5 = 1.147 ± 0.005) and an intrinsic KIE on the HAT step (Dk > 15). The close energy barrier between αKG decarboxylation and HAT distinguishes FIH as an O2-sensing enzyme and is crucial for ensuring substrate specificity in the regulation of cellular O2 homeostasis.


Assuntos
Hipóxia Celular/fisiologia , Hidrogênio/metabolismo , Oxigenases de Função Mista/metabolismo , Proteínas Repressoras/metabolismo , Aclimatação , Adaptação Fisiológica , Dioxigenases/metabolismo , Metabolismo Energético/fisiologia , Homeostase , Humanos , Hipóxia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Isótopos , Cinética , Oxigenases de Função Mista/fisiologia , Proteínas Repressoras/fisiologia , Especificidade por Substrato
8.
Carcinogenesis ; 42(3): 369-377, 2021 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-33300568

RESUMO

Genome-wide association studies (GWAS) of esophageal adenocarcinoma (EAC) and its precursor, Barrett's esophagus (BE), have uncovered significant genetic components of risk, but most heritability remains unexplained. Targeted assessment of genetic variation in biologically relevant pathways using novel analytical approaches may identify missed susceptibility signals. Central obesity, a key BE/EAC risk factor, is linked to systemic inflammation, altered hormonal signaling and insulin-like growth factor (IGF) axis dysfunction. Here, we assessed IGF-related genetic variation and risk of BE and EAC. Principal component analysis was employed to evaluate pathway-level and gene-level associations with BE/EAC, using genotypes for 270 single-nucleotide polymorphisms (SNPs) in or near 12 IGF-related genes, ascertained from 3295 BE cases, 2515 EAC cases and 3207 controls in the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) GWAS. Gene-level signals were assessed using Multi-marker Analysis of GenoMic Annotation (MAGMA) and SNP summary statistics from BEACON and an expanded GWAS meta-analysis (6167 BE cases, 4112 EAC cases, 17 159 controls). Global variation in the IGF pathway was associated with risk of BE (P = 0.0015). Gene-level associations with BE were observed for GHR (growth hormone receptor; P = 0.00046, false discovery rate q = 0.0056) and IGF1R (IGF1 receptor; P = 0.0090, q = 0.0542). These gene-level signals remained significant at q < 0.1 when assessed using data from the largest available BE/EAC GWAS meta-analysis. No significant associations were observed for EAC. This study represents the most comprehensive evaluation to date of inherited genetic variation in the IGF pathway and BE/EAC risk, providing novel evidence that variation in two genes encoding cell-surface receptors, GHR and IGF1R, may influence risk of BE.


Assuntos
Adenocarcinoma/genética , Esôfago de Barrett/genética , Biomarcadores Tumorais/genética , Neoplasias Esofágicas/genética , Somatomedinas/metabolismo , Adenocarcinoma/patologia , Idoso , Esôfago de Barrett/patologia , Biomarcadores Tumorais/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Neoplasias Esofágicas/patologia , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Mutação em Linhagem Germinativa , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo , Fatores de Risco , Transdução de Sinais/genética
9.
J Am Chem Soc ; 143(43): 18216-18232, 2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34677973

RESUMO

Extended anionic frameworks based on condensation of polyhedral main group non-metal anions offer a wide range of structure types. Despite the widespread chemistry and earth abundance of phosphates and silicates, there are no reports of extended ultraphosphate anions with lithium. We describe the lithium ultraphosphates Li3P5O14 and Li4P6O17 based on extended layers and chains of phosphate, respectively. Li3P5O14 presents a complex structure containing infinite ultraphosphate layers with 12-membered rings that are stacked alternately with lithium polyhedral layers. Two distinct vacant tetrahedral sites were identified at the end of two distinct finite Li6O1626- chains. Li4P6O17 features a new type of loop-branched chain defined by six PO43- tetrahedra. The ionic conductivities and electrochemical properties of Li3P5O14 were examined by impedance spectroscopy combined with DC polarization, NMR spectroscopy, and galvanostatic plating/stripping measurements. The structure of Li3P5O14 enables three-dimensional lithium migration that affords the highest ionic conductivity (8.5(5) × 10-7 S cm-1 at room temperature for bulk), comparable to that of commercialized LiPON glass thin film electrolytes, and lowest activation energy (0.43(7) eV) among all reported ternary Li-P-O phases. Both new lithium ultraphosphates are predicted to have high thermodynamic stability against oxidation, especially Li3P5O14, which is predicted to be stable to 4.8 V, significantly higher than that of LiPON and other solid electrolytes. The condensed phosphate units defining these ultraphosphate structures offer a new route to optimize the interplay of conductivity and electrochemical stability required, for example, in cathode coatings for lithium ion batteries.

10.
Gastroenterology ; 159(6): 2065-2076.e1, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32918910

RESUMO

BACKGROUND & AIMS: Esophageal adenocarcinoma (EA) and its premalignant lesion, Barrett's esophagus (BE), are characterized by a strong and yet unexplained male predominance (with a male-to-female ratio in EA incidence of up to 6:1). Genome-wide association studies (GWAS) have identified more than 20 susceptibility loci for these conditions. However, potential sex differences in genetic associations with BE/EA remain largely unexplored. METHODS: Given strong genetic overlap, BE and EA cases were combined into a single case group for analysis. These were compared with population-based controls. We performed sex-specific GWAS of BE/EA in 3 separate studies and then used fixed-effects meta-analysis to provide summary estimates for >9 million variants for male and female individuals. A series of downstream analyses were conducted separately in male and female individuals to identify genes associated with BE/EA and the genetic correlations between BE/EA and other traits. RESULTS: We included 6758 male BE/EA cases, 7489 male controls, 1670 female BE/EA cases, and 6174 female controls. After Bonferroni correction, our meta-analysis of sex-specific GWAS identified 1 variant at chromosome 6q11.1 (rs112894788, KHDRBS2-MTRNR2L9, PBONF = .039) that was statistically significantly associated with BE/EA risk in male individuals only, and 1 variant at chromosome 8p23.1 (rs13259457, PRSS55-RP1L1, PBONF = 0.057) associated, at borderline significance, with BE/EA risk in female individuals only. We also observed strong genetic correlations of BE/EA with gastroesophageal reflux disease in male individuals and obesity in female individuals. CONCLUSIONS: The identified novel sex-specific variants associated with BE/EA could improve the understanding of the genetic architecture of the disease and the reasons for the male predominance.


Assuntos
Adenocarcinoma/genética , Esôfago de Barrett/genética , Biomarcadores Tumorais/genética , Neoplasias Esofágicas/genética , Predisposição Genética para Doença , Adenocarcinoma/epidemiologia , Esôfago de Barrett/epidemiologia , Estudos de Casos e Controles , Neoplasias Esofágicas/epidemiologia , Proteínas do Olho/genética , Feminino , Refluxo Gastroesofágico/epidemiologia , Refluxo Gastroesofágico/genética , Loci Gênicos , Estudo de Associação Genômica Ampla , Humanos , Masculino , Obesidade/epidemiologia , Obesidade/genética , Polimorfismo de Nucleotídeo Único , Proteínas de Ligação a RNA/genética , Medição de Risco , Fatores de Risco , Serina Endopeptidases/genética , Fatores Sexuais
11.
J Synchrotron Radiat ; 28(Pt 1): 146-157, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33399563

RESUMO

For high-resolution powder diffraction in material science, high photon energies are necessary, especially for in situ and in operando experiments. For this purpose, a multi-analyser detector (MAD) was developed for the high-energy beamline P02.1 at PETRA III of the Deutsches Elektronen-Synchrotron (DESY). In order to be able to adjust the detector for the high photon energies of 60 keV, an individually adjustable analyser-crystal setup was designed. The adjustment is performed via piezo stepper motors for each of the ten channels. The detector shows a low and flat background as well as a high signal-to-noise ratio. A range of standard materials were measured for characterizing the performance. Two exemplary experiments were performed to demonstrate the potential for sophisticated structural analysis with the MAD: (i) the structure of a complex material based on strontium niobate titanate and strontium niobate zirconate was determined and (ii) an in situ stroboscopy experiment with an applied electric field on a highly absorbing piezoceramic was performed. These experiments demonstrate the capabilities of the new MAD, which advances the frontiers of the structural characterization of materials.

12.
Mol Ecol ; 30(23): 6370-6386, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33973288

RESUMO

Climate warming, in particular in island environments, where opportunities for species to disperse are limited, may become a serious threat to cold adapted alpine species. In order to understand how alpine species may respond to a warming world, we need to understand the drivers that have shaped their habitat specialisation and the evolutionary adaptations that allow them to utilize alpine habitats. The endemic, endangered New Zealand kea (Nestor notabilis) is considered the only alpine parrot in the world. As a species commonly found in the alpine zone it may be highly susceptible to climate warming. But is it a true alpine specialist? Is its evolution driven by adaptation to the alpine zone, or is the kea an open habitat generalist that simply uses the alpine zone to, for example, avoid lower lying anthropogenic landscapes? We use whole genome data of the kea and its close, forest adapted sister species, the kaka (Nestor meridionalis) to reconstruct the evolutionary history of both species and identify the functional genomic differences that underlie their habitat specialisations. Our analyses do not identify major functional genomic differences between kea and kaka in pathways associated with high-altitude. Rather, we found evidence that selective pressures on adaptations commonly found in alpine species are present in both Nestor species, suggesting that selection for alpine adaptations has not driven their divergence. Strongly divergent demographic responses to past climate warming between the species nevertheless highlight potential future threats to kea survival in a warming world.


Assuntos
Papagaios , Adaptação Fisiológica/genética , Animais , Ecologia , Genômica , Repetições de Microssatélites
13.
Inorg Chem ; 60(10): 6999-7007, 2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-33938223

RESUMO

A new perovskite oxide semiconductor, CaCu3Fe2Ta2O12, was synthesized through a high-pressure and high-temperature approach. The compound possesses an Im3̅ space group, where it crystallizes to an A-site-ordered but B-site partial ordered quadruple perovskite structure. Spin ordering occurs around 150 K owing to the antiferromagnetic coupling between Fe3+ spins and ferromagnetic coupling between Cu2+ spins. The room-temperature dielectric permittivity of CaCu3Fe2Ta2O12 was measured to be approximately 2500 at 1 kHz. More importantly, isothermal frequency-dielectric spectroscopy demonstrates the existence of two dielectric relaxations. Debye-like relaxation is attributed to charge carriers trapped among the oxygen vacancies at low temperatures and Maxwell-Wagner polarization relaxation at high temperatures. CaCu3Fe2Ta2O12 is a new magnetic semiconductor, where A-site ordering is intercorrelated with second-order Jahn-Teller distortion. These findings offer opportunities to design novel perovskite oxides with attractive magnetic and dielectric properties.

14.
Proc Natl Acad Sci U S A ; 115(30): 7771-7776, 2018 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-29987016

RESUMO

New Zealand's geographic isolation, lack of native terrestrial mammals, and Gondwanan origins make it an ideal location to study evolutionary processes. However, since the archipelago was first settled by humans 750 y ago, its unique biodiversity has been under pressure, and today an estimated 49% of the terrestrial avifauna is extinct. Current efforts to conserve the remaining fauna rely on a better understanding of the composition of past ecosystems, as well as the causes and timing of past extinctions. The exact temporal and spatial dynamics of New Zealand's extinct fauna, however, can be difficult to interpret, as only a small proportion of animals are preserved as morphologically identifiable fossils. Here, we conduct a large-scale genetic survey of subfossil bone assemblages to elucidate the impact of humans on the environment in New Zealand. By genetically identifying more than 5,000 nondiagnostic bone fragments from archaeological and paleontological sites, we reconstruct a rich faunal record of 110 species of birds, fish, reptiles, amphibians, and marine mammals. We report evidence of five whale species rarely reported from New Zealand archaeological middens and characterize extinct lineages of leiopelmatid frog (Leiopelma sp.) and kakapo (Strigops habroptilus) haplotypes lost from the gene pool. Taken together, this molecular audit of New Zealand's subfossil record not only contributes to our understanding of past biodiversity and precontact Maori subsistence practices but also provides a more nuanced snapshot of anthropogenic impacts on native fauna after first human arrival.


Assuntos
Biodiversidade , Osso e Ossos , DNA/genética , Fósseis , Pool Gênico , Animais , DNA/química , DNA/isolamento & purificação , Nova Zelândia
15.
Stat Appl Genet Mol Biol ; 18(4)2019 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-32996465

RESUMO

Genomic imprinting is a parent-of-origin effect apparent in an appreciable number of human diseases. We have proposed the new imprinting test statistic MOBIT, which is based on MOD score analysis. We were interested in the properties of the MOBIT concerning its distribution under three hypotheses: (1) H0,a: no linkage, no imprinting; (2) H0,b: linkage, no imprinting; (3) H1: linkage and imprinting. More specifically, we assessed the confounding between imprinting and sex-specific recombination frequencies, which presents a major difficulty in linkage-based testing for imprinting, and evaluated the power of the test. To this end, we have performed a linkage simulation study of affected sib-pairs and a three-generation pedigree with two trait models, many two- and multipoint marker scenarios, three genetic map ratios, two sample sizes, and five imprinting degrees. We also investigated the ability of the MOBIT to quantify the degree of imprinting and applied the MOBIT using a real data example on house dust mite allergy. We further proposed and evaluated two approaches to obtain empiric p values for the MOBIT. Our results showed that twopoint analyses assuming a sex-averaged marker map led to an inflated type I error due to confounding, especially for a larger marker-trait locus distance. When the correct sex-specific marker map was assumed, twopoint analyses have a reduced power to detect imprinting, compared to sex-averaged analyses with an appropriate correction for the inflation of the test statistic. However, confounding was not an issue in multipoint analysis unless the map ratio was extreme and marker spacing was sparse. With multipoint analysis, power as well as the ability to quantify the imprinting degree were almost equally high when a sex-averaged or the correct sex-specific map was used in the analysis. We recommend to obtain empiric p values for the MOBIT using genotype simulations based on the best-fitting nonimprinting model of the real dataset analysis. In addition, an implementation of a method based on the permutation of parental sexes is also available. In summary, we propose to perform multipoint analyses using densely spaced markers to efficiently discover new imprinted loci and to reliably quantify the degree of imprinting.


Assuntos
Impressão Genômica , Projetos de Pesquisa , Feminino , Ligação Genética , Genótipo , Humanos , Escore Lod , Masculino , Modelos Genéticos , Linhagem
16.
Biochemistry ; 58(39): 4047-4057, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499004

RESUMO

Protein dynamics are crucial for the mechanistically ordered enzymes to bind to their substrate in the correct sequence and perform catalysis. Factor-inhibiting HIF-1 (FIH) is a nonheme Fe(II) α-ketoglutarate-dependent oxygenase that is a key hypoxia (low pO2) sensor in humans. As these hypoxia-sensing enzymes follow a multistep chemical mechanism consuming α-ketoglutarate, a protein substrate that is hydroxylated, and O2, understanding protein flexibility and the order of substrate binding may aid in the development of strategies for selective targeting. The primary substrate of FIH is the C-terminal transactivation domain (CTAD) of hypoxia-inducible factor 1α (HIF) that is hydroxylated on the side chain of Asn803. We assessed changes in protein flexibility connected to metal and αKG binding, finding that (M+αKG) binding significantly stabilized the cupin barrel core of FIH as evidenced by enhanced thermal stability and decreased protein dynamics as assessed by global amide hydrogen/deuterium exchange mass spectrometry and limited proteolysis. Confirming predictions of the consensus mechanism, (M+αKG) increased the affinity of FIH for CTAD as measured by titrations monitoring intrinsic tryptophan fluorescence. The decreased protein dynamics caused by (M+αKG) enforces a sequentially ordered substrate binding sequence in which αKG binds before CTAD, suggesting that selective inhibition may require inhibitors that target the binding sites of both αKG and the prime substrate. A consequence of the correlation between dynamics and αKG binding is that all relevant ligands must be included in binding-based inhibitor screens, as shown by testing permutations of M, αKG, and inhibitor.


Assuntos
Subunidade alfa do Fator 1 Induzível por Hipóxia/química , Ácidos Cetoglutáricos/química , Oxigenases de Função Mista/química , Proteínas Repressoras/química , Sítios de Ligação , Catálise , Dicroísmo Circular , Escherichia coli/metabolismo , Humanos , Espectrometria de Massa com Troca Hidrogênio-Deutério , Hidroxilação , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Ácidos Cetoglutáricos/metabolismo , Cinética , Manganês/química , Oxigenases de Função Mista/metabolismo , Oxigênio/metabolismo , Plasmídeos/química , Ligação Proteica , Domínios Proteicos , Proteólise , Proteínas Repressoras/metabolismo , Especificidade por Substrato
17.
J Am Chem Soc ; 141(6): 2305-2315, 2019 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-30652858

RESUMO

Orthorhombic V2O5 nanowires were successfully synthesized via a hydrothermal method. A cell-configuration system was built utilizing V2O5 as the cathode and 1 M Mg(ClO4)2 electrolyte within acetonitrile, together with Mg xMo6S8 ( x ≈ 2) as the anode to investigate the structural evolution and oxidation state and local structural changes of V2O5. The V2O5 nanowires deliver an initial discharge/charge capacity of 103 mAh g-1/110 mAh g-1 and the highest discharge capacity of 130 mAh g-1 in the sixth cycle at C/20 rate in the cell-configuration system. In operando synchrotron diffraction and in operando X-ray absorption spectroscopy together with ex situ Raman and X-ray photoelectron spectroscopy reveal the reversibility of magnesium insertion/extraction and provide information on the crystal structure evolution and changes of the oxidation states during cycling.

18.
Hum Mol Genet ; 26(4): 829-842, 2017 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-28087736

RESUMO

Nonsyndromic cleft lip with or without cleft palate (nsCL/P) is among the most common human birth defects with multifactorial etiology. Here, we present results from a genome-wide imputation study of nsCL/P in which, after adding replication cohort data, four novel risk loci for nsCL/P are identified (at chromosomal regions 2p21, 14q22, 15q24 and 19p13). On a systematic level, we show that the association signals within this high-density dataset are enriched in functionally-relevant genomic regions that are active in both human neural crest cells (hNCC) and mouse embryonic craniofacial tissue. This enrichment is also detectable in hNCC regions primed for later activity. Using GCTA analyses, we suggest that 30% of the estimated variance in risk for nsCL/P in the European population can be attributed to common variants, with 25.5% contributed to by the 24 risk loci known to date. For each of these, we identify credible SNPs using a Bayesian refinement approach, with two loci harbouring only one probable causal variant. Finally, we demonstrate that there is no polygenic component of nsCL/P detectable that is shared with nonsyndromic cleft palate only (nsCPO). Our data suggest that, while common variants are strongly contributing to risk for nsCL/P, they do not seem to be involved in nsCPO which might be more often caused by rare deleterious variants. Our study generates novel insights into both nsCL/P and nsCPO etiology and provides a systematic framework for research into craniofacial development and malformation.


Assuntos
Cromossomos Humanos/genética , Fenda Labial/genética , Fissura Palatina/genética , Bases de Dados Genéticas , Loci Gênicos , Estudo de Associação Genômica Ampla , Polimorfismo de Nucleotídeo Único , Animais , Fenda Labial/metabolismo , Fenda Labial/patologia , Fissura Palatina/metabolismo , Fissura Palatina/patologia , Feminino , Humanos , Masculino , Camundongos
19.
Am J Hum Genet ; 98(4): 755-62, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-27018475

RESUMO

Nonsyndromic cleft lip with/without cleft palate (nsCL/P) and nonsyndromic cleft palate only (nsCPO) are the most frequent subphenotypes of orofacial clefts. A common syndromic form of orofacial clefting is Van der Woude syndrome (VWS) where individuals have CL/P or CPO, often but not always associated with lower lip pits. Recently, ∼5% of VWS-affected individuals were identified with mutations in the grainy head-like 3 gene (GRHL3). To investigate GRHL3 in nonsyndromic clefting, we sequenced its coding region in 576 Europeans with nsCL/P and 96 with nsCPO. Most strikingly, nsCPO-affected individuals had a higher minor allele frequency for rs41268753 (0.099) than control subjects (0.049; p = 1.24 × 10(-2)). This association was replicated in nsCPO/control cohorts from Latvia, Yemen, and the UK (pcombined = 2.63 × 10(-5); ORallelic = 2.46 [95% CI 1.6-3.7]) and reached genome-wide significance in combination with imputed data from a GWAS in nsCPO triads (p = 2.73 × 10(-9)). Notably, rs41268753 is not associated with nsCL/P (p = 0.45). rs41268753 encodes the highly conserved p.Thr454Met (c.1361C>T) (GERP = 5.3), which prediction programs denote as deleterious, has a CADD score of 29.6, and increases protein binding capacity in silico. Sequencing also revealed four novel truncating GRHL3 mutations including two that were de novo in four families, where all nine individuals harboring mutations had nsCPO. This is important for genetic counseling: given that VWS is rare compared to nsCPO, our data suggest that dominant GRHL3 mutations are more likely to cause nonsyndromic than syndromic CPO. Thus, with rare dominant mutations and a common risk variant in the coding region, we have identified an important contribution for GRHL3 in nsCPO.


Assuntos
Fissura Palatina/genética , Proteínas de Ligação a DNA/genética , Predisposição Genética para Doença , Fases de Leitura Aberta , Fatores de Transcrição/genética , Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Alelos , Estudos de Casos e Controles , Fenda Labial/diagnóstico , Fenda Labial/genética , Fissura Palatina/diagnóstico , Cistos/diagnóstico , Cistos/genética , Humanos , Lábio/anormalidades , Mutação , Polimorfismo de Nucleotídeo Único , Grupos Raciais/genética
20.
Clin Gastroenterol Hepatol ; 17(11): 2227-2235.e1, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30716477

RESUMO

BACKGROUND & AIMS: Epidemiology studies of circulating concentrations of 25 hydroxy vitamin D (25(OH)D) and risk of esophageal adenocarcinoma (EAC) have produced conflicting results. We conducted a Mendelian randomization study to determine the associations between circulating concentrations of 25(OH)D and risks of EAC and its precursor, Barrett's esophagus (BE). METHODS: We conducted a Mendelian randomization study using a 2-sample (summary data) approach. Six single-nucleotide polymorphisms (SNPs; rs3755967, rs10741657, rs12785878, rs10745742, rs8018720, and rs17216707) associated with circulating concentrations of 25(OH)D were used as instrumental variables. We collected data from 6167 patients with BE, 4112 patients with EAC, and 17,159 individuals without BE or EAC (controls) participating in the Barrett's and Esophageal Adenocarcinoma Consortium, as well as studies from Bonn, Germany, and Cambridge and Oxford, United Kingdom. Analyses were performed separately for BE and EAC. RESULTS: Overall, we found no evidence for an association between genetically estimated 25(OH)D concentration and risk of BE or EAC. The odds ratio per 20 nmol/L increase in genetically estimated 25(OH)D concentration for BE risk estimated by combining the individual SNP association using inverse variance weighting was 1.21 (95% CI, 0.77-1.92; P = .41). The odds ratio for EAC risk, estimated by combining the individual SNP association using inverse variance weighting, was 0.68 (95% CI, 0.39-1.19; P = .18). CONCLUSIONS: In a Mendelian randomization study, we found that low genetically estimated 25(OH)D concentrations were not associated with risk of BE or EAC.


Assuntos
Adenocarcinoma/genética , Esôfago de Barrett/genética , Neoplasias Esofágicas/genética , Análise da Randomização Mendeliana/métodos , Polimorfismo de Nucleotídeo Único , Medição de Risco , Vitamina D/sangue , Adenocarcinoma/sangue , Adenocarcinoma/epidemiologia , Esôfago de Barrett/sangue , Esôfago de Barrett/epidemiologia , Biomarcadores Tumorais/sangue , DNA de Neoplasias/genética , Neoplasias Esofágicas/sangue , Neoplasias Esofágicas/epidemiologia , Europa (Continente)/epidemiologia , Feminino , Humanos , Masculino , Morbidade , América do Norte/epidemiologia , Fatores de Risco
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