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1.
Cogn Emot ; : 1-13, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38712807

RESUMO

Sustained attention, a key cognitive skill that improves during childhood and adolescence, tends to be worse in some emotional and behavioural disorders. Sustained attention is typically studied in non-affective task contexts; here, we used a novel task to index performance in affective versus neutral contexts across adolescence (N = 465; ages 11-18). We asked whether: (i) performance would be worse in negative versus neutral task contexts; (ii) performance would improve with age; (iii) affective interference would be greater in younger adolescents; (iv) adolescents at risk for depression and higher in anxiety would show overall worse performance; and (v) would show differential performance in negative contexts. Results indicated that participants performed more poorly in negative contexts and showed age-related performance improvements. Those at risk of depression performed more poorly than those at lower risk. However, there was no difference between groups as a result of affective context. For anxiety there was no difference in performance as a function of severity. However, those with higher anxiety showed less variance in their reaction times to negative stimuli than those with lower anxiety. One interpretation is that moderate levels of emotional arousal associated with anxiety make individuals less susceptible to the distracting effects of negative stimuli.

2.
Heliyon ; 9(11): e21112, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37954362

RESUMO

Squat defects are one of the most common rail surface defects. Significant research effort has gone into understand squat defects over the last 10 years which has brought about important developments in the understanding of their initiation mechanism; however, further work is still required to fully understand squat and the best methods to control them. This study considers records of squat defects over a period 9 years, considering 2600 km of track across 8 different routes on the GB mainline network. The analysis separately reviews squats on: plainline, crossings, joints and welds. Results include an overview of the main factors influencing the development of each type of squats, practical methods to immediately reduce and manage squat defects and recommends focus areas for further research to understand squat defects. Results suggest that squats on plainline, crossings, joints and welds, all correlate with different influencing factors; headcheck defects appear to significantly influence the probability of squats and how other factors influence squat development. There is a strong connection between total head wear rate (combined material removal due to traffic and grinding) and squats; 90 % of all squats appear on rail with a headwear rate of <0.2 mm/year. Overall larger section rail (60 kg/m vs 56 kg/m) and harder material (260 Brinell vs 220 Brinell) is significantly less susceptible to squat damage. Track curvature has an influence of squat development, especially in rail with no headcheck cracking, where the tightest curves are significantly more likely to sustain squat damage. The probability of squat at vertical discontinuities, i.e. joints and crossings are significantly more likely as train speed increases. Whilst squats on joints are 1000 time more likely than squats on welds.

3.
Nature ; 602(7895): 63-67, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35110756

RESUMO

Electrically charged particles can be created by the decay of strong enough electric fields, a phenomenon known as the Schwinger mechanism1. By electromagnetic duality, a sufficiently strong magnetic field would similarly produce magnetic monopoles, if they exist2. Magnetic monopoles are hypothetical fundamental particles that are predicted by several theories beyond the standard model3-7 but have never been experimentally detected. Searching for the existence of magnetic monopoles via the Schwinger mechanism has not yet been attempted, but it is advantageous, owing to the possibility of calculating its rate through semi-classical techniques without perturbation theory, as well as that the production of the magnetic monopoles should be enhanced by their finite size8,9 and strong coupling to photons2,10. Here we present a search for magnetic monopole production by the Schwinger mechanism in Pb-Pb heavy ion collisions at the Large Hadron Collider, producing the strongest known magnetic fields in the current Universe11. It was conducted by the MoEDAL experiment, whose trapping detectors were exposed to 0.235 per nanobarn, or approximately 1.8 × 109, of Pb-Pb collisions with 5.02-teraelectronvolt center-of-mass energy per collision in November 2018. A superconducting quantum interference device (SQUID) magnetometer scanned the trapping detectors of MoEDAL for the presence of magnetic charge, which would induce a persistent current in the SQUID. Magnetic monopoles with integer Dirac charges of 1, 2 and 3 and masses up to 75 gigaelectronvolts per speed of light squared were excluded by the analysis at the 95% confidence level. This provides a lower mass limit for finite-size magnetic monopoles from a collider search and greatly extends previous mass bounds.

4.
Phys Rev Lett ; 126(7): 071801, 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33666471

RESUMO

The MoEDAL trapping detector consists of approximately 800 kg of aluminum volumes. It was exposed during run 2 of the LHC program to 6.46 fb^{-1} of 13 TeV proton-proton collisions at the LHCb interaction point. Evidence for dyons (particles with electric and magnetic charge) captured in the trapping detector was sought by passing the aluminum volumes comprising the detector through a superconducting quantum interference device (SQUID) magnetometer. The presence of a trapped dyon would be signaled by a persistent current induced in the SQUID magnetometer. On the basis of a Drell-Yan production model, we exclude dyons with a magnetic charge ranging up to five Dirac charges (5g_{D}) and an electric charge up to 200 times the fundamental electric charge for mass limits in the range 870-3120 GeV and also monopoles with magnetic charge up to and including 5g_{D} with mass limits in the range 870-2040 GeV.

5.
Philos Trans R Soc Lond B Biol Sci ; 376(1816): 20190726, 2021 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-33250029

RESUMO

This paper responds to a resurgence of interest in constructing long-term time proxies of human activity, especially but not limited to models of population change over the Pleistocene and/or Holocene. While very much agreeing with the need for this increased attention, we emphasize three important issues that can all be thought of as modifiable reporting unit problems: the impact of (i) archaeological periodization, (ii) uneven event durations and (iii) geographical nucleation-dispersal phenomena. Drawing inspiration from real-world examples from prehistoric Britain, Greece and Japan, we explore their consequences and possible mitigation via a reproducible set of tactical simulations. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.


Assuntos
Arqueologia , Demografia , Atividades Humanas , Dinâmica Populacional , Grécia , Humanos , Japão , Reino Unido
6.
Philos Trans A Math Phys Eng Sci ; 377(2161): 20190392, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31707967

RESUMO

The search for highly ionizing particles in nuclear track detectors (NTDs) traditionally requires experts to manually search through samples in order to identify regions of interest that could be a hint of physics beyond the standard model of particle physics. The advent of automated image acquisition and modern data science, including machine learning-based processing of data presents an opportunity to accelerate the process of searching for anomalies in NTDs that could be a hint of a new physics avatar. The potential for modern data science applied to this topic in the context of the MoEDAL experiment at the large Hadron collider at the European Centre for Nuclear Research, CERN, is discussed. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

7.
Phys Rev Lett ; 123(2): 021802, 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31386510

RESUMO

MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we update our previous search for magnetic monopoles in Run 2 using the full trapping detector with almost four times more material and almost twice more integrated luminosity. For the first time at the LHC, the data were interpreted in terms of photon-fusion monopole direct production in addition to the Drell-Yan-like mechanism. The MoEDAL trapping detector, consisting of 794 kg of aluminum samples installed in the forward and lateral regions, was exposed to 4.0 fb^{-1} of 13 TeV proton-proton collisions at the LHCb interaction point and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to or above the Dirac charge are excluded in all samples. Monopole spins 0, ½, and 1 are considered and both velocity-independent and-dependent couplings are assumed. This search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.

8.
Phys Rev Lett ; 121(26): 261801, 2018 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-30636113

RESUMO

We present first evidence that the cosine of the CP-violating weak phase 2ß is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle using a time-dependent Dalitz plot analysis of B^{0}→D^{(*)}h^{0} with D→K_{S}^{0}π^{+}π^{-} decays, where h^{0}∈{π^{0},η,ω} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the ϒ(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6}BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6}BB[over ¯] pairs recorded by the Belle detector. The results of the measurement are sin2ß=0.80±0.14(stat)±0.06(syst)±0.03(model) and cos2ß=0.91±0.22(stat)±0.09(syst)±0.07(model). The result for the direct measurement of the angle ß of the CKM Unitarity Triangle is ß=[22.5±4.4(stat)±1.2(syst)±0.6(model)]°. The measurement assumes no direct CP violation in B^{0}→D^{(*)}h^{0} decays. The quoted model uncertainties are due to the composition of the D^{0}→K_{S}^{0}π^{+}π^{-} decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e^{+}e^{-}→cc[over ¯] data sample. CP violation is observed in B^{0}→D^{(*)}h^{0} decays at the level of 5.1 standard deviations. The significance for cos2ß>0 is 3.7 standard deviations. The trigonometric multifold solution π/2-ß=(68.1±0.7)° is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.

9.
J Sch Health ; 87(8): 630-637, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28691170

RESUMO

BACKGROUND: We examined the body mass index (BMI) of students attending Seventh-day Adventist (Adventist) schools in Australia in 2001 and 2012. METHODS: A total of 3069 students attending Adventist schools in Australia responded to a health and lifestyle survey in 2001 (N = 1335) and 2012 (N = 1734). The survey captured self-reported height and weight, demographics (age, sex, year level, religion), and select health behaviors. RESULTS: Compared with national norms, lower rates of overweight and obesity were observed in the study cohort, but higher rates of underweight. There was no change in the mean BMI of the students attending Adventist schools in Australia from 2001 to 2012. Regression analyses indicated that a lower BMI was associated with age, sex, more regularly eating breakfast, consuming less soft drink, and having a regular exercise program. The students reported a high consumption of fruits, vegetables, and whole grains compared with Australian national norms, and 29% claimed to be vegetarian. CONCLUSIONS: Students attending Adventist schools appear to have a lower prevalence of overweight and obesity than the secular population, but a higher prevalence of underweight. The mechanisms through which Adventist schools may influence student's BMI warrants further investigation.


Assuntos
Saúde do Adolescente/estatística & dados numéricos , Nível de Saúde , Estado Nutricional , Protestantismo , Adolescente , Fenômenos Fisiológicos da Nutrição do Adolescente , Austrália , Índice de Massa Corporal , Feminino , Humanos , Masculino , Obesidade Infantil/epidemiologia , Análise de Regressão
10.
Phys Rev Lett ; 115(12): 121604, 2015 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-26430984

RESUMO

We report a measurement of the time-dependent CP asymmetry of B[over ¯]^{0}→D_{CP}^{(*)}h^{0} decays, where the light neutral hadron h^{0} is a π^{0}, η, or ω meson, and the neutral D meson is reconstructed in the CP eigenstates K^{+}K^{-}, K_{S}^{0}π^{0}, or K_{S}^{0}ω. The measurement is performed combining the final data samples collected at the ϒ(4S) resonance by the BABAR and Belle experiments at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6} BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6} BB[over ¯] pairs recorded by the Belle detector. We measure the CP asymmetry parameters -η_{f}S=+0.66±0.10(stat)±0.06(syst) and C=-0.02±0.07(stat)±0.03(syst). These results correspond to the first observation of CP violation in B[over ¯]^{0}→D_{CP}^{(*)}h^{0} decays. The hypothesis of no mixing-induced CP violation is excluded in these decays at the level of 5.4 standard deviations.

11.
Lancet ; 385(9975): 1305-14, 2015 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-25529582

RESUMO

BACKGROUND: Human genome sequencing has transformed our understanding of genomic variation and its relevance to health and disease, and is now starting to enter clinical practice for the diagnosis of rare diseases. The question of whether and how some categories of genomic findings should be shared with individual research participants is currently a topic of international debate, and development of robust analytical workflows to identify and communicate clinically relevant variants is paramount. METHODS: The Deciphering Developmental Disorders (DDD) study has developed a UK-wide patient recruitment network involving over 180 clinicians across all 24 regional genetics services, and has performed genome-wide microarray and whole exome sequencing on children with undiagnosed developmental disorders and their parents. After data analysis, pertinent genomic variants were returned to individual research participants via their local clinical genetics team. FINDINGS: Around 80,000 genomic variants were identified from exome sequencing and microarray analysis in each individual, of which on average 400 were rare and predicted to be protein altering. By focusing only on de novo and segregating variants in known developmental disorder genes, we achieved a diagnostic yield of 27% among 1133 previously investigated yet undiagnosed children with developmental disorders, whilst minimising incidental findings. In families with developmentally normal parents, whole exome sequencing of the child and both parents resulted in a 10-fold reduction in the number of potential causal variants that needed clinical evaluation compared to sequencing only the child. Most diagnostic variants identified in known genes were novel and not present in current databases of known disease variation. INTERPRETATION: Implementation of a robust translational genomics workflow is achievable within a large-scale rare disease research study to allow feedback of potentially diagnostic findings to clinicians and research participants. Systematic recording of relevant clinical data, curation of a gene-phenotype knowledge base, and development of clinical decision support software are needed in addition to automated exclusion of almost all variants, which is crucial for scalable prioritisation and review of possible diagnostic variants. However, the resource requirements of development and maintenance of a clinical reporting system within a research setting are substantial. FUNDING: Health Innovation Challenge Fund, a parallel funding partnership between the Wellcome Trust and the UK Department of Health.


Assuntos
Deficiências do Desenvolvimento/diagnóstico , Genoma Humano/genética , Adolescente , Criança , Pré-Escolar , Deficiências do Desenvolvimento/genética , Feminino , Variação Genética/genética , Estudo de Associação Genômica Ampla/métodos , Heterozigoto , Humanos , Achados Incidentais , Lactente , Recém-Nascido , Disseminação de Informação , Masculino , Fenótipo , Manejo de Espécimes
12.
Nucleic Acids Res ; 42(Database issue): D993-D1000, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24150940

RESUMO

The DECIPHER database (https://decipher.sanger.ac.uk/) is an accessible online repository of genetic variation with associated phenotypes that facilitates the identification and interpretation of pathogenic genetic variation in patients with rare disorders. Contributing to DECIPHER is an international consortium of >200 academic clinical centres of genetic medicine and ≥1600 clinical geneticists and diagnostic laboratory scientists. Information integrated from a variety of bioinformatics resources, coupled with visualization tools, provides a comprehensive set of tools to identify other patients with similar genotype-phenotype characteristics and highlights potentially pathogenic genes. In a significant development, we have extended DECIPHER from a database of just copy-number variants to allow upload, annotation and analysis of sequence variants such as single nucleotide variants (SNVs) and InDels. Other notable developments in DECIPHER include a purpose-built, customizable and interactive genome browser to aid combined visualization and interpretation of sequence and copy-number variation against informative datasets of pathogenic and population variation. We have also introduced several new features to our deposition and analysis interface. This article provides an update to the DECIPHER database, an earlier instance of which has been described elsewhere [Swaminathan et al. (2012) DECIPHER: web-based, community resource for clinical interpretation of rare variants in developmental disorders. Hum. Mol. Genet., 21, R37-R44].


Assuntos
Variações do Número de Cópias de DNA , Bases de Dados de Ácidos Nucleicos , Genótipo , Fenótipo , Genoma Humano , Humanos , Internet , Doenças Raras/genética
13.
Hum Mol Genet ; 21(R1): R37-44, 2012 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-22962312

RESUMO

Patients with developmental disorders often harbour sub-microscopic deletions or duplications that lead to a disruption of normal gene expression or perturbation in the copy number of dosage-sensitive genes. Clinical interpretation for such patients in isolation is hindered by the rarity and novelty of such disorders. The DECIPHER project (https://decipher.sanger.ac.uk) was established in 2004 as an accessible online repository of genomic and associated phenotypic data with the primary goal of aiding the clinical interpretation of rare copy-number variants (CNVs). DECIPHER integrates information from a variety of bioinformatics resources and uses visualization tools to identify potential disease genes within a CNV. A two-tier access system permits clinicians and clinical scientists to maintain confidential linked anonymous records of phenotypes and CNVs for their patients that, with informed consent, can subsequently be shared with the wider clinical genetics and research communities. Advances in next-generation sequencing technologies are making it practical and affordable to sequence the whole exome/genome of patients who display features suggestive of a genetic disorder. This approach enables the identification of smaller intragenic mutations including single-nucleotide variants that are not accessible even with high-resolution genomic array analysis. This article briefly summarizes the current status and achievements of the DECIPHER project and looks ahead to the opportunities and challenges of jointly analysing structural and sequence variation in the human genome.


Assuntos
Variações do Número de Cópias de DNA , Bases de Dados de Ácidos Nucleicos , Deficiências do Desenvolvimento/genética , Doenças Genéticas Inatas/genética , Internet , Biologia Computacional , Predisposição Genética para Doença , Variação Genética , Genoma Humano , Humanos , Disseminação de Informação , Mutação , Fenótipo , Polimorfismo de Nucleotídeo Único
14.
Faraday Discuss ; 151: 353-67; discussion 385-97, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22455080

RESUMO

This project involved the conversion of a British Waterways maintenance craft to a canal boat, powered by a combination of a solid-state hydrogen store, Proton Exchange Membrane (PEM) fuel cell, lead-acid battery pack and a high-efficiency, permanent magnet (NdFeB) electric motor. These replaced the conventional diesel engine thus eliminating water, noise, local and general atmospheric pollution. The "Protium" project applies modern technologies to a traditional mode of transportation. The TiMn2-based metal hydride store exhibited excellent performance as an effective means of storing 4 kg of hydrogen with a suitable desorption flow rate and temperature adequate for the operation of a 1 kW PEM fuel cell in a water-based environment.

15.
Occup Med (Lond) ; 60(7): 525-31, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20696648

RESUMO

BACKGROUND: The Health & Safety Executive's (HSE) Indicator Tool offers a measure of exposure to psychosocial work conditions that may be linked to stress-related outcomes. The HSE recommends that Indicator Tool data should be used as a basis for discussions concerned with the identification of psychosocial work conditions that might warrant prioritization for intervention. However, operational constraints may render discussions difficult to convene and, when they do take place, the absence of information on harms associated with exposures can make it difficult to identify intervention priorities. AIMS: To examine (i) the utility of the Indicator Tool for the identification of a manageable number of psychosocial work conditions as intervention candidates and (ii) whether administration of a measure of stress-related outcomes alongside the Indicator Tool can facilitate the identification of intervention priorities. METHODS: One thousand and thirty-eight employees in the London region of the Her Majesty's Prison Service completed the Indicator Tool and a measure of psychological well-being. Odds ratios were calculated to estimate the risk of impairment to well-being associated with exposure to psychosocial work conditions. RESULTS: The Indicator Tool identified 34 psychosocial work conditions as warranting improvement. Intervention priority was given to those working conditions that were both reported to be poor by ≥50% of respondents and associated with risk of impairment to well-being. This method allowed for the identification of four areas. CONCLUSIONS: Augmentation of the Indicator Tool with a measure of stress-related outcomes and the calculation of simple risk estimation statistics can assist the prioritization of intervention candidates.


Assuntos
Doenças Profissionais/prevenção & controle , Exposição Ocupacional , Saúde Ocupacional , Prisões , Estresse Psicológico/prevenção & controle , Local de Trabalho/psicologia , Adolescente , Adulto , Feminino , Humanos , Londres , Masculino , Pessoa de Meia-Idade , Doenças Profissionais/epidemiologia , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/estatística & dados numéricos , Razão de Chances , Medição de Risco/métodos , Estresse Psicológico/epidemiologia , Inquéritos e Questionários , Local de Trabalho/organização & administração , Adulto Jovem
16.
Am J Hum Genet ; 84(4): 524-33, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19344873

RESUMO

Many patients suffering from developmental disorders harbor submicroscopic deletions or duplications that, by affecting the copy number of dosage-sensitive genes or disrupting normal gene expression, lead to disease. However, many aberrations are novel or extremely rare, making clinical interpretation problematic and genotype-phenotype correlations uncertain. Identification of patients sharing a genomic rearrangement and having phenotypic features in common leads to greater certainty in the pathogenic nature of the rearrangement and enables new syndromes to be defined. To facilitate the analysis of these rare events, we have developed an interactive web-based database called DECIPHER (Database of Chromosomal Imbalance and Phenotype in Humans Using Ensembl Resources) which incorporates a suite of tools designed to aid the interpretation of submicroscopic chromosomal imbalance, inversions, and translocations. DECIPHER catalogs common copy-number changes in normal populations and thus, by exclusion, enables changes that are novel and potentially pathogenic to be identified. DECIPHER enhances genetic counseling by retrieving relevant information from a variety of bioinformatics resources. Known and predicted genes within an aberration are listed in the DECIPHER patient report, and genes of recognized clinical importance are highlighted and prioritized. DECIPHER enables clinical scientists worldwide to maintain records of phenotype and chromosome rearrangement for their patients and, with informed consent, share this information with the wider clinical research community through display in the genome browser Ensembl. By sharing cases worldwide, clusters of rare cases having phenotype and structural rearrangement in common can be identified, leading to the delineation of new syndromes and furthering understanding of gene function.


Assuntos
Aberrações Cromossômicas , Bases de Dados Genéticas , Adulto , Criança , Pré-Escolar , Hibridização Genômica Comparativa , Biologia Computacional , Feminino , Dosagem de Genes , Genes Dominantes , Genoma Humano , Humanos , Internet , Masculino , Fenótipo , Síndrome
17.
Neurocase ; 9(2): 118-28, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12925936

RESUMO

This paper is the first report of an aphasic patient (GT) who shows a selective impairment in naming musical notes and letters in the context of preserved instrumental reading of notes. The ability to orally name notes (which are given the letter names A-G in English) and to play notes from a spoken note name was severely impaired. By contrast, instrumental sightreading and matching of written letters and single notes were both well preserved. This complex pattern of impairments can be explained in terms of a selective deficit in the letter name system.


Assuntos
Afasia/psicologia , Música , Adulto , Cognição , Humanos , Idioma , Masculino , Percepção Visual
18.
Mol Biol Cell ; 12(12): 3821-38, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11739783

RESUMO

Eukaryotic cells have the ability to degrade proteins and organelles by selective and nonselective modes of micro- and macroautophagy. In addition, there exist both constitutive and regulated forms of autophagy. For example, pexophagy is a selective process for the regulated degradation of peroxisomes by autophagy. Our studies have shown that the differing pathways of autophagy have many molecular events in common. In this article, we have identified a new member in the family of autophagy genes. GSA12 in Pichia pastoris and its Saccharomyces cerevisiae counterpart, CVT18, encode a soluble protein with two WD40 domains. We have shown that these proteins are required for pexophagy and autophagy in P. pastoris and the Cvt pathway, autophagy, and pexophagy in S. cerevisiae. In P. pastoris, Gsa12 appears to be required for an early event in pexophagy. That is, the involution of the vacuole or extension of vacuole arms to engulf the peroxisomes does not occur in the gsa12 mutant. Consistent with its role in vacuole engulfment, we have found that this cytosolic protein is also localized to the vacuole surface. Similarly, Cvt18 displays a subcellular localization that distinguishes it from the characterized proteins required for cytoplasm-to-vacuole delivery pathways.


Assuntos
Autofagia , Citoplasma/metabolismo , Pichia/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Vacúolos/metabolismo , Sequência de Aminoácidos , Proteínas Relacionadas à Autofagia , Transporte Biológico , Divisão Celular , Membrana Celular/metabolismo , Proteínas de Membrana , Microscopia Eletrônica , Dados de Sequência Molecular , Mutação , Peroxissomos/metabolismo , Pichia/citologia , Pichia/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Homologia de Sequência de Aminoácidos , Fatores de Tempo
19.
J Biol Chem ; 276(45): 42422-35, 2001 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-11533052

RESUMO

Cells are capable of adapting to changes in their environment by synthesizing needed proteins and degrading superfluous ones. Pichia pastoris synthesizes peroxisomal enzymes to grow in methanol medium. Upon adapting from methanol medium to one containing glucose, this yeast rapidly and selectively degrades peroxisomes by an autophagic process referred to as pexophagy. In this study, we have utilized a novel approach to identify genes required for this degradative pathway. Our approach involves the random integration of a vector containing the Zeocin resistance gene into the yeast genome by restriction enzyme-mediated integration. Cells unable to degrade peroxisomes during glucose adaptation were isolated, and the genes that were disrupted by the insertion of the vector were determined by sequencing. By using this approach, we have identified a number of genes required for glucose-induced selective autophagy of peroxisomes (GSA genes). We report here the characterization of Gsa11, a unique 208-kDa protein. We found that this protein is required for glucose-induced pexophagy and starvation-induced autophagy. Gsa11 is a cytosolic protein that becomes associated with one or more structures situated near the vacuole during glucose adaptation. The punctate localization of Gsa11 was not observed in gsa10, gsa12, gsa14, and gsa19 mutants. We have previously shown that Gsa9 appears to relocate from a compartment at the vacuole surface to regions between the vacuole and the peroxisomes being sequestered. In the gsa11 mutants, the vacuole only partially surrounded the peroxisomes, but Gsa9 was still distributed around the peroxisome cluster. This suggests that Gsa9 binds to the peroxisomes independent of the vacuole. The data also indicate that Gsa11 is not necessary for Gsa9 to interact with peroxisomes but acts at an intermediate event required for the vacuole to engulf the peroxisomes.


Assuntos
Proteínas Fúngicas/fisiologia , Glucose/farmacologia , Pichia/química , Sequência de Aminoácidos , Autofagia , Citoplasma/metabolismo , Dados de Sequência Molecular , Peso Molecular , Peroxissomos/metabolismo , Vacúolos/metabolismo
20.
J Med Virol ; 64(2): 175-82, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11360250

RESUMO

Increased expression of inducible nitric oxide synthase (iNOS) has been found in inflammatory myocardial disease and increased production of nitric oxide (NO) has both an inhibitory effect on virus replication and a cytotoxic effect on host cells. To investigate the relationship between severity of enteroviral myocarditis and iNOS expression, a characterised murine model was infected with either cardiovirulent or an attenuated Coxsackievirus B3 and myocardial samples were collected on Day 7. The ability of these viruses to induce NOS expression was compared by measurement of iNOS enzyme activity and localisation of iNOS protein or peroxynitrite, a product of excessive NO production. In accordance with previous reports, high expression of iNOS was detected in mice infected with the cardiovirulent virus. The iNOS protein was located mainly in infiltrating macrophages in and around foci of necrotic myofibres where viral genomic RNA was detected. In contrast, the level of iNOS expression was significantly lower in mice infected with the attenuated virus. This correlates with fewer and smaller myocarditic lesions and less infiltrating cells in the heart. iNOS was not detected in mock-infected mice by the above assays. These findings suggest that one mechanism of attenuation may be associated with the reduced ability of the variant to induce NOS expression in the heart. This also confirms a cytotoxic role for NO in the pathogenesis of Coxsackievirus B3-induced myocarditis.


Assuntos
Enterovirus , Miocardite/virologia , Óxido Nítrico Sintase/metabolismo , Tirosina/análogos & derivados , Animais , Modelos Animais de Doenças , Enterovirus/genética , Enterovirus/isolamento & purificação , Enterovirus/patogenicidade , Guanosina Monofosfato/sangue , Coração/virologia , Imuno-Histoquímica , Masculino , Camundongos , Miocardite/sangue , Miocardite/metabolismo , Miocárdio/metabolismo , Nitratos/análise , Óxido Nítrico Sintase/análise , Óxido Nítrico Sintase Tipo II , Hibridização de Ácido Nucleico , RNA Viral/análise , Tirosina/análise
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