RESUMEN
Visual working memory (VWM) allows storing goal-relevant information to guide future behavior. Prior work suggests that VWM is spatially organized and relies on spatial attention directed toward locations at which memory items were encoded, even if location is task-irrelevant. Importantly, attention often needs to be dynamically redistributed between locations, for example, in preparation for an upcoming probe. Very little is known about how attentional resources are distributed between multiple locations during a VWM task and even less about the dynamic changes governing such attentional shifts over time. This is largely due to the inability to use behavioral outcomes to reveal fast dynamic changes within trials. We here demonstrated that EEG steady-state visual evoked potentials (SSVEPs) successfully track the dynamic allocation of spatial attention during a VWM task. Participants were presented with to-be-memorized gratings and distractors at two distinct locations, tagged with flickering discs. This allowed us to dynamically track attention allocated to memory and distractor items via their coupling with space by quantifying the amplitude and coherence of SSVEP responses in the EEG signal to flickering stimuli at the former memory and distractor locations. SSVEP responses did not differ between memory and distractor locations during early maintenance. However, shortly before probe comparison, we observed a decrease in SSVEP coherence over distractor locations indicative of a reallocation of spatial attentional resources. RTs were shorter when preceded by stronger decreases in SSVEP coherence at distractor locations, likely reflecting attentional shifts from the distractor to the probe or memory location. We demonstrate that SSVEPs can inform about dynamic processes in VWM, even if location does not have to be reported by participants. This finding not only supports the notion of a spatially organized VWM but also reveals that SSVEPs betray a dynamic prioritization process of working memory items and locations over time that is directly predictive of memory performance.
Asunto(s)
Potenciales Evocados Visuales , Memoria a Corto Plazo , Humanos , Memoria a Corto Plazo/fisiología , Atención/fisiología , Cognición , Motivación , Percepción Visual/fisiología , Potenciales EvocadosRESUMEN
An amperometric sensor based on an inkjet-printed graphene electrode (IPGE) modified with amine-functionalized montmorillonite (Mt-NH2) for the electroanalysis and quantification of gentisic acid (GA) has been developed. The organoclay used as IPGE modifier was prepared and characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, CHN elemental analysis, and thermogravimetry. The electrochemical features of the Mt-NH2/IPGE sensor were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The sensor exhibited charge selectivity ability which was exploited for the electrochemical oxidation of GA. The GA amperometric response was high in acidic medium (Brinton-Robinson buffer, pH 2) due to favorable interactions between the protonated amine groups and the negatively charged GA. Kinetic studies were also performed by cyclic voltammetry, and the obtained electron transfer rate constant of 11.3 s-1 indicated a fast direct electron transfer rate of GA to the electrode. An approach using differential pulse voltammetry was then developed for the determination of GA (at + 0.233 V vs. a pseudo Ag/Ag+ reference electrode), and under optimized conditions, the sensor showed high sensitivity, a wide working linear range from 1 to 21 µM (R2 = 0.999), and a low detection limit of 0.33 µM (0.051 ± 0.01 mg L-1). The proposed sensor was applied to quantify GA in a commercial red wine sample. The simple and rapid method developed using a cheap clay material could be employed for the determination of various phenolic acids.
Asunto(s)
Bentonita/química , Gentisatos/análisis , Grafito/química , Técnicas Electroquímicas/métodos , Electrodos , Gentisatos/química , Límite de Detección , Oxidación-Reducción , Impresión , Vino/análisisRESUMEN
Modification of host hormone biology is a common strategy used by plant pathogens to promote disease. For example, the bacterial pathogen strain Pseudomonas syringae DC3000 (PtoDC3000) produces the plant hormone auxin (indole-3-acetic acid [IAA]) to promote PtoDC3000 growth in plant tissue. Previous studies suggest that auxin may promote PtoDC3000 pathogenesis through multiple mechanisms, including both suppression of salicylic acid (SA)-mediated host defenses and via an unknown mechanism that appears to be independent of SA. To test if host auxin signaling is important during pathogenesis, we took advantage of Arabidopsis thaliana lines impaired in either auxin signaling or perception. We found that disruption of auxin signaling in plants expressing an inducible dominant axr2-1 mutation resulted in decreased bacterial growth and that this phenotype was suppressed by introducing the sid2-2 mutation, which impairs SA synthesis. Thus, host auxin signaling is required for normal susceptibility to PtoDC3000 and is involved in suppressing SA-mediated defenses. Unexpectedly, tir1 afb1 afb4 afb5 quadruple-mutant plants lacking four of the six known auxin coreceptors that exhibit decreased auxin perception, supported increased levels of bacterial growth. This mutant exhibited elevated IAA levels and reduced SA-mediated defenses, providing additional evidence that auxin promotes disease by suppressing host defense. We also investigated the hypothesis that IAA promotes PtoDC3000 virulence through a direct effect on the pathogen and found that IAA modulates expression of virulence genes, both in culture and in planta. Thus, in addition to suppressing host defenses, IAA acts as a microbial signaling molecule that regulates bacterial virulence gene expression.
Asunto(s)
Arabidopsis/microbiología , Ácidos Indolacéticos/metabolismo , Enfermedades de las Plantas/microbiología , Inmunidad de la Planta , Pseudomonas syringae/patogenicidad , Virulencia , Regulación de la Expresión Génica de las Plantas , Mutación , Pseudomonas syringae/genética , Ácido Salicílico/metabolismo , Transducción de SeñalRESUMEN
microRNAs regulate dynamic aspects of innate immunity in Arabidopsis thaliana in response to lipopolysaccharides. Lectin-domain receptor-like kinases function as surveillance proteins and miR393 targets transcripts of an L-type LecRK (LECRK-V.7, At3g59740). This study investigated miR393 regulation of LecRLKs associated with LPS perception. Following pre-treatment of wild type -, miR393â¯ab double mutant - and miR393 overexpressor plants with LPS, the expression of miR393 and two other LecRLK genes (G-type lectin S-receptor-like protein kinases, SD1-13 (At1g11330) and SD1-29 (At1g61380) were evaluated. Overexpression and repression of miR393 respectively suppressed and induced transcripts of the LecRLK genes. The results indicate that miR393 regulates the three LecRLKs following perception of bacterial LPS, in support of immunity and basal resistance.
Asunto(s)
Proteínas de Arabidopsis/inmunología , Arabidopsis/inmunología , MicroARNs/inmunología , Inmunidad de la Planta , Proteínas Serina-Treonina Quinasas/inmunología , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Inmunidad Innata , Lipopolisacáridos/inmunología , MicroARNs/genética , Proteínas Serina-Treonina Quinasas/genéticaRESUMEN
BACKGROUND: Plants respond to various stress stimuli by activating an enhanced broad-spectrum defensive ability. The development of novel resistance inducers represents an attractive, alternative crop protection strategy. In this regard, hexanoic acid (Hxa, a chemical elicitor) and azelaic acid (Aza, a natural signaling compound) have been proposed as inducers of plant defense, by means of a priming mechanism. Here, we investigated both the mode of action and the complementarity of Aza and Hxa as priming agents in Nicotiana tabacum cells in support of enhanced defense. RESULTS: Metabolomic analyses identified signatory biomarkers involved in the establishment of a pre-conditioned state following Aza and Hxa treatment. Both inducers affected the metabolomes in a similar manner and generated common biomarkers: caffeoylputrescine glycoside, cis-5-caffeoylquinic acid, feruloylglycoside, feruloyl-3-methoxytyramine glycoside and feruloyl-3-methoxytyramine conjugate. Subsequently, quantitative real time-PCR was used to investigate the expression of inducible defense response genes: phenylalanine ammonia lyase, hydroxycinnamoyl CoA quinate transferase and hydroxycinnamoyl transferase to monitor activation of the early phenylpropanoid pathway and chlorogenic acids metabolism, while ethylene response element-binding protein, small sar1 GTPase, heat shock protein 90, RAR1, SGT1, non-expressor of PR genes 1 and thioredoxin were analyzed to report on signal transduction events. Pathogenesis-related protein 1a and defensin were quantified to investigate the activation of defenses regulated by salicylic acid and jasmonic acid respectively. The qPCR results revealed differential expression kinetics and, in general (except for NPR1, Thionin and PR1a), the relative gene expression ratios observed in the Hxa-treated cells were significantly greater than the expression observed in the cells treated with Aza. CONCLUSIONS: The results indicate that Aza and Hxa have a similar priming effect through activation of genes involved in the establishment of systemic acquired resistance, associated with enhanced synthesis of hydroxycinnamic acids and related conjugates.
Asunto(s)
Caproatos/farmacología , Ácidos Dicarboxílicos/farmacología , Nicotiana/efectos de los fármacos , Biomarcadores , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Metaboloma/efectos de los fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transducción de Señal , Nicotiana/genética , Nicotiana/inmunología , Nicotiana/metabolismo , Factores de Transcripción/metabolismo , Transcriptoma/efectos de los fármacosRESUMEN
BACKGROUND: MicroRNAs (miRNAs) are non-coding RNA molecules which have recently emerged as important gene regulators in plants and their gene expression analysis is becoming increasingly important. miRNAs regulate gene expression at the post-transcriptional level by translational repression or target degradation of specific mRNAs and gene silencing. In order to profile the microtranscriptome of Arabidopsis thaliana leaf and callus tissues in response to bacterial lipopolysaccharide (LPS), small RNA libraries were constructed at 0 and 3 h post induction with LPS and sequenced by Illumina sequencing technology. RESULTS: Differential regulation of subset of miRNAs in response to LPS treament was observed. Small RNA reads were mapped to the miRNA database and 358 miRNAs belonging to 49 miRNA families in the callus tissues and 272 miRNAs belonging to 40 miRNA families in the leaf tissues were identified. Moreover, target genes for all the identified miRNAs families in the leaf tissues and 44 of the 49 miRNAs families in the callus tissues were predicted. The sequencing analysis showed that in both callus and leaf tissues, various stress regulated-miRNAs were differentially expressed and real time PCR validated the expression profile of miR156, miR158, miR159, miR169, miR393, miR398, miR399 and miR408 along with their target genes. CONCLUSION: A. thaliana callus and leaf callus tissues respond to LPS as a microbe-associated molecular pattern molecule through dynamic changes to the microtranscriptome associated with differential transcriptional regulation in support of immunity and basal resistance.
Asunto(s)
Arabidopsis/citología , Arabidopsis/genética , Lipopolisacáridos/farmacología , Células Vegetales/metabolismo , Hojas de la Planta/genética , Transcriptoma/genética , Arabidopsis/efectos de los fármacos , Secuencia de Bases , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , MicroARNs/genética , MicroARNs/metabolismo , Datos de Secuencia Molecular , Células Vegetales/efectos de los fármacos , Hojas de la Planta/efectos de los fármacos , Reacción en Cadena en Tiempo Real de la Polimerasa , Análisis de Secuencia de ARN , Transcriptoma/efectos de los fármacosRESUMEN
A composite material prepared by polymerization of ß-cyclodextrin (ß-CD) on the surface of natural hydroxyapatite using citric acid as cross linker, was employed as electrode material for the detection of Pb(II). Hydroxyapatite was obtained from bovine bones, following a three-step procedure including pre-calcination, chemical treatment with (NH4)2HPO4, and calcination. The structure and morphology of the pristine hydroxyapatite (NHAPP0.5) and its functionalized counterpart (NHAPp0.5-CA-ß-CD) were examined using XRD, FTIR, and SEM. Upon deposition as thin film on a glassy carbon electrode (GCE), the ion exchange ability of NHAPp0.5-CA-ß-CD was exploited to elaborate a sensitive sensor for the detection of lead. The electroanalytical procedure was based on the chemical accumulation of Pb(II) ions under open-circuit conditions, followed by the detection of the preconcentrated species using differential pulse anodic stripping voltammetry. The reproducibility of the proposed method, based on a series of 8 measurements in a solution containing 2 µM Pb(II) gave a coefficient of variation of 1.27%. Significant parameters that can affect the stripping response of Pb(II) were optimized, leading to a linear calibration curve for lead in the concentration range of 2 × 10-8 mol L-1 - 20 × 10-8 mol L-1 (R2 = 0.998). The detection limit (3S/m) and the sensitivity of the proposed sensor were 5.06 × 10-10 mol L-1 and 100.80 µA.µM-1, respectively. The interfering effect of several ions expected to affect the determination of lead was evaluated, and the proposed sensor was successfully applied in the determination of Pb(II) ions in spring water, well water, river water and tap water samples.
Asunto(s)
Durapatita , beta-Ciclodextrinas , Animales , Bovinos , Electrodos , Plomo , Polimerizacion , Reproducibilidad de los ResultadosRESUMEN
Defense responses of tomato (Solanum lycopersicum L.) against attack by Pectobacterium carotovorum subsp. carotovorum (Pcc), the causal agent of soft rot diseases, were studied. The expression of some tomato defense genes were evaluated by real-time PCR quantification analysis, 24 and 72 hr after actively growing tomato plants were inoculated with Pcc. These included: MYB transcriptor factor, ethylene response element-binding protein, suppressor of the G2 allele of Skp1, cytochrome P450, small Sar1 GTPase, hydroxycinnamoyl-CoA:quinate hydroxycinnamoyl transferase, pathogenesis-related protein 1a, endo-1,3-beta-glucanase, chitinase, proteinase inhibitor, defensin, CC-NBS-LRR resistance protein, and phenylalanine ammonia lyase. The results showed dynamic transcriptomic changes, with transcripts exhibiting different expression kinetics at 24 and 72 hr to confer resistance to tomato against Pcc infection.
Asunto(s)
Regulación de la Expresión Génica de las Plantas , Interacciones Huésped-Patógeno/genética , Pectobacterium carotovorum , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Solanum lycopersicum/genética , Solanum lycopersicum/microbiología , Perfilación de la Expresión Génica , TranscriptomaRESUMEN
Metabolomics has emerged as a powerful approach to comprehensively interrogate cellular biochemistry. As such, we applied an untargeted liquid chromatography-mass spectrometry metabolomic strategy to elucidate metabolome changes in the anthracnose-causing hemibiotrophic sorghum pathogen, Colletotrichum sublineolum. An in vitro batch culture study model with different carbon sources, glucose, arabinose and rhamnose, were used to support fungal growth over a period of twelve days. Metabolites representing the intracellular and extracellular (secreted) metabolomes were extracted with methanol and subjected to LC-MS analyses. Chemometric modelling revealed a metabolic variation trajectory, comprising three distinct stages that metabolically describe the adaptation of the fungus to diminishing nutrients. Selected marker gene expression indicated stage one (0-3 d.p.i) as corresponding to the early logarithmic phase. Stage two can be interpreted as an intermediate transitionary stage with stage three corresponding to the stationary phase (9-12 d.p.i). Stage one was characterised by up-regulation of endo-metabolites such as ferricrocin, fatty acids and flavone-conjugates, while stage three was characterised by the secretion of phytotoxins, including colletotrichin and colletotric acid. Ultimately, results from our in vitro model reveal previously unknown insights into the dynamic aspects of metabolome reprogramming in the growth phases of Colletotrichum spp as determined by nutrients obtainable from plant cell walls.
Asunto(s)
Colletotrichum/metabolismo , Metaboloma , Metabolómica , Colletotrichum/crecimiento & desarrollo , Enfermedades de las Plantas/microbiologíaRESUMEN
The metabolome of a biological system provides a functional readout of the cellular state, thus serving as direct signatures of biochemical events that define the dynamic equilibrium of metabolism and the correlated phenotype. Hence, to elucidate biochemical processes involved in sorghum responses to fungal infection, a liquid chromatography-mass spectrometry-based untargeted metabolomic study was designed. Metabolic alterations of three sorghum cultivars responding to Colletotrichum sublineolum, were investigated. At the 4-leaf growth stage, the plants were inoculated with fungal spore suspensions and the infection monitored over time: 0, 3, 5, 7, and 9 days post inoculation. Non-infected plants were used as negative controls. The metabolite composition of aqueous-methanol extracts were analyzed on an ultra-high performance liquid chromatography system coupled to high-definition mass spectrometry. The acquired multidimensional data were processed to create data matrices for multivariate statistical analysis and chemometric modeling. The computed chemometric models indicated time- and cultivar-related metabolic changes that reflect sorghum responses to the fungal infection. Metabolic pathway and correlation-based network analyses revealed that this multi-component defense response is characterized by a functional metabolic web, containing defense-related molecular cues to counterattack the pathogen invasion. Components of this network are metabolites from a range of interconnected metabolic pathways with the phenylpropanoid and flavonoid pathways being the central hub of the web. One of the key features of this altered metabolism was the accumulation of an array of phenolic compounds, particularly de novo biosynthesis of the antifungal 3-deoxyanthocynidin phytoalexins, apigeninidin, luteolinidin, and related conjugates. The metabolic results were complemented by qRT-PCR gene expression analyses that showed upregulation of defense-related marker genes. Unraveling key characteristics of the biochemical mechanism underlying sorghum-C. sublineolum interactions, provided valuable insights with potential applications in breeding crop plants with enhanced disease resistance. Furthermore, the study contributes to ongoing efforts toward a comprehensive understanding of the regulation and reprogramming of plant metabolism under biotic stress.
RESUMEN
MicroRNAs (miRNAs) are a class of small non-coding RNAs that have recently emerged as important regulators of gene expression, mainly through cleavage and/or translation inhibition of the target mRNAs during or after transcription. miRNAs play important roles by regulating a multitude of biological processes in plants which include maintenance of genome integrity, development, metabolism, and adaptive responses toward environmental stresses. The increasing population of the world and their food demands requires focused efforts for the improvement of crop plants to ensure sustainable food production. Manipulation of mRNA transcript abundance via miRNA control provides a unique strategy for modulating differential plant gene expression and miRNAs are thus emerging as the next generation targets for genetic engineering for improvement of the agronomic properties of crops. However, a deeper understanding of its potential and the mechanisms involved will facilitate the design of suitable strategies to obtain the desirable traits with minimum trade-offs in the modified crops. In this regard, this review highlights the diverse roles of conserved and newly identified miRNAs in various food and industrial crops and recent advances made in the uses of miRNAs to improve plants of agronomically importance so as to significantly enhance crop yields and increase tolerance to various environmental stress agents of biotic-or abiotic origin.
RESUMEN
With the increasing use of enzymes in environmental applications, there is a need for analytical methods adapted to large factorial experiments. Existing reference methods are chemical and labor intensive and unsuitable to analyze in parallel a large number of samples. Based on an extensive literature review and on experimental results, this work compares reference and microplate adapted methods to define the most adequate filter paper, carboxymethylcellulase, ß-glucosidase and xylanase activity tests. In the adapted methods, the total reaction volume was reduced from 2.2-24.5 mL to 0.21-0.24 mL. Statistical analysis of the activities measured on enzyme mixtures by applying the 96-well plate reduced methods showed that they were not significantly different to the activities obtained with reference tests.
Asunto(s)
Bioensayo , Celulasa/metabolismo , Técnicas de Química Analítica/instrumentación , Técnicas de Química Analítica/métodos , Endo-1,4-beta Xilanasas/metabolismo , Filtros Microporos , beta-Glucosidasa/metabolismoRESUMEN
Plants respond to various stress stimuli by activating broad-spectrum defense responses both locally as well as systemically. As such, identification of expressed genes represents an important step towards understanding inducible defense responses and assists in designing appropriate intervention strategies for disease management. Genes differentially expressed in tobacco cell suspensions following elicitation with isonitrosoacetophenone (INAP) were identified using mRNA differential display and pyro-sequencing. Sequencing data produced 14579 reads, which resulted in 198 contigs and 1758 singletons. Following BLAST analyses, several inducible plant defense genes of interest were identified and classified into functional categories including signal transduction, transcription activation, transcription and protein synthesis, protein degradation and ubiquitination, stress-responsive, defense-related, metabolism and energy, regulation, transportation, cytoskeleton and cell wall-related. Quantitative PCR was used to investigate the expression of 17 selected target genes within these categories. Results indicate that INAP has a sensitising or priming effect through activation of salicylic acid-, jasmonic acid- and ethylene pathways that result in an altered transcriptome, with the expression of genes involved in perception of pathogens and associated cellular re-programming in support of defense. Furthermore, infection assays with the pathogen Pseudomonas syringae pv. tabaci confirmed the establishment of a functional anti-microbial environment in planta.
Asunto(s)
Resistencia a la Enfermedad/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Nicotiana/metabolismo , Fenilglioxal/análogos & derivados , Enfermedades de las Plantas , Transcripción Genética/efectos de los fármacos , Fenilglioxal/farmacología , Células Vegetales/metabolismo , Pseudomonas syringae/metabolismo , Nicotiana/citologíaRESUMEN
BACKGROUND: Although aortic wave reflection may be inherited, the extent to which indexes of wave reflection derived from wave separation analysis (reflected (backward) wave index (RI) and pressure (Pb)) show intrafamilial aggregation and heritability is uncertain. We therefore aimed to determine the intrafamilial aggregation and heritability of RI and Pb and compare these with indexes of pressure augmentation. METHODS: Aortic Pb, RI, augmented pressure (Pa), and augmentation index (AIx) were determined using radial applanation tonometry and SphygmoCor software in 1,152 participants of 315 families (111 father-mother, 705 parent-child, and 301 sibling-sibling pairs) from an urban developing community of black Africans. Heritability estimates were determined from Statistical Analysis for Genetic Epidemiology software. RESULTS: With appropriate adjustments, significant correlations were noted between parent-child pairs for Pb and Pa (P < 0.05 for all), but not for RI (P = 0.50) or AIx (P = 0.90) and between sib-sib pairs for Pb and Pa (P < 0.05), but not for RI (P = 0.54) or AIx (P = 0.14). No correlations for indexes of wave reflection were noted between fathers and mothers (P > 0.57). After adjustments, Pb (h2 = 0.24±0.07) and Pa (h2 = 0.23±0.07) (P < 0.001 for both) but not RI (h2 = 0.04±0.06, P = 0.27) or AIx (h2 = 0.10±0.07, P = 0.07) showed significant heritability. CONCLUSIONS: Aortic reflected (backward) waves derived from either wave separation (Pb) or pulse wave analysis (Pa) show a similar degree of intrafamilial aggregation and heritability, but the use of RI or AIx may underestimate reflected wave effects.
Asunto(s)
Presión Arterial/genética , Análisis de la Onda del Pulso , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Quantum dots exhibit extraordinary optical and mechanical properties, and the number of their applications is increasing. In order to investigate a possible effect of coating on the inhalation toxicity of previously tested non-coated CdS/Cd(OH)2 quantum dots and translocation of these very small particles from the lungs, rats were exposed to coated quantum dots or CdCl2 aerosol (since Cd(2+) was present as impurity), 6h/d for 5 consecutive days. Cd content was determined in organs and excreta after the end of exposure and three weeks thereafter. Toxicity was determined by examination of broncho-alveolar lavage fluid and microscopic evaluation of the entire respiratory tract. There was no evidence for translocation of particles from the respiratory tract. Evidence of a minimal inflammatory process was observed by examination of broncho-alveolar lavage fluid. Microscopically, minimal to mild epithelial alteration was seen in the larynx. The effects observed with coated quantum dots, non-coated quantum dots and CdCl2 were comparable, indicating that quantum dots elicited no significant effects beyond the toxicity of the Cd(2+) ion itself. Compared to other compounds with larger particle size tested at similarly low concentrations, quantum dots caused much less pronounced toxicological effects. Therefore, the present data show that small particle sizes with corresponding high surfaces are not the only factor triggering the toxic response or translocation.
Asunto(s)
Compuestos de Cadmio/toxicidad , Glutaral/toxicidad , Hidróxidos/toxicidad , Puntos Cuánticos/toxicidad , Sistema Respiratorio/efectos de los fármacos , Sulfuros/toxicidad , Aerosoles , Animales , Líquido del Lavado Bronquioalveolar , Cloruro de Cadmio/toxicidad , Compuestos de Cadmio/metabolismo , Compuestos de Cadmio/orina , Heces/química , Glutaral/metabolismo , Glutaral/orina , Hidróxidos/metabolismo , Hidróxidos/orina , Exposición por Inhalación , Masculino , Tamaño de la Partícula , Puntos Cuánticos/metabolismo , Ratas , Ratas Wistar , Sistema Respiratorio/metabolismo , Sistema Respiratorio/patología , Sulfuros/metabolismo , Sulfuros/orina , Factores de Tiempo , Distribución Tisular , Pruebas de Toxicidad AgudaRESUMEN
OBJECTIVE: An inability to show consistent relationships between gene variants and blood pressure (BP) may be confounded by the use of office BP measurement. Whether the difference between office BP and day BP (office-day) is genetically predetermined is unknown. We therefore aimed to determine the intrafamilial aggregation and heritability of office-day BP. PATIENTS AND METHODS: Nurse-derived office BP (mean of 5 measurements according to guidelines) and 24-h ambulatory BP were determined for 592 participants from 198 families (67 spouse pairs, 361 parent-child pairs, and 169 sibling-sibling pairs), with 12 families having three generations, from an urban developing community of black Africans. Heritability estimates were determined using SAGE software. RESULTS: With adjustments for confounders, office systolic BP (SBP) (h=0.35±0.09, P<0.0001) showed comparable heritability estimates to 24-h SBP (h=0.33±0.09, P<0.0001). Similarly, with adjustments for confounders, office diastolic BP (DBP) (h=0.37±0.09, P<0.0001) showed comparable heritability estimates as 24-h DBP (h=0.35±0.09, P<0.0001). However, multivariate adjusted heritability estimates of day SBP (h=0.29±0.09, P<0.0001) and DBP (h=0.33±0.09, P<0.0001) were not diminished by further adjustments for office SBP (h=0.42±0.09, P<0.0001) or DBP (h=0.34±0.09, P<0.0001). Further, independent of confounders, office-day BP showed significant intrafamilial aggregation and heritability (SBP: h=0.51±0.10, P<0.0001; DBP: h=0.37±0.09, P<0.0001), effects that persisted with further adjustments for office, day, or day-night BP (P<0.0005 for SBP and DBP). CONCLUSION: Although office and ambulatory BP may show similar heritability estimates, genetic associations with carefully determined office BP measurements may be confounded by the heritability of office-day BP differences.
Asunto(s)
Población Negra/genética , Monitoreo Ambulatorio de la Presión Arterial , Presión Sanguínea/genética , Estudios de Asociación Genética , Adulto , Anciano , Familia , Humanos , Persona de Mediana EdadRESUMEN
The characteristic of transmissible spongiform encephalopathies (TSE) is an accumulation of partially protease resistant (PrP(res)) abnormal prion protein (PrP(sc)). This pathological prion protein is very resistant to conventional inactivation methods. The risk of transmission of TSE, such as Creutzfeldt-Jakob disease (CJD), by biopharmaceutical products prepared from human cells must be taken into account. The nanofiltration process has been proved to be effective in removing viruses and scrapie agent. The major advantages of this technique are flexibility and efficacy in removing infectious particles without altering biopharmaceutical characteristics and properties. This study focused on the removal of human PrP(sc) by means of a nanofiltration method after spiking a Lymphoglobuline solution with a CJD brain homogenate. Lymphoglobuline equine anti-human thymocyte immunoglobulin is a selective immunosuppressive agent acting mainly on human T lymphocytes. The therapeutic indications are: immunosuppression for transplantation: prevention and treatment of graft rejection; treatment of aplastic anemia. In our study, CJD homogenate was spiked at three different dilutions (low, moderate and high) in the Lymphoglobuline product. The nanofiltration process was performed on each sample. Using the western blot technique, the PrP(res) signal detected in nanofiltrates was compared to that obtained with a reference scale (dilution series of CJD brain homogenate in Lymphoglobuline detected by western blot and elaborated on 3.3 log). After nanofiltration, the PrP(res) western blot signal was detected with a significant reduction in the less dilute sample, whereas the signal was undetectable in the two other samples. These are the first data in CJD demonstrating a clearance between 1.6 and 3.3 log with a Lymphoglobuline recovery of over 93%. The nanofiltration process confirms its relative efficacy in removing human CJD PrP(sc).
Asunto(s)
Síndrome de Creutzfeldt-Jakob/prevención & control , Contaminación de Medicamentos , Inmunoglobulinas/química , Proteínas PrPSc/aislamiento & purificación , Ultrafiltración/métodos , Animales , Síndrome de Creutzfeldt-Jakob/transmisión , Humanos , Inmunoglobulinas Intravenosas/química , Nanotecnología , Soluciones/químicaRESUMEN
The hard x-ray imaging spectrometer (HXIS) is one of the instruments aboard the NASA Solar Maximum Mission satellite. For the imaging of solar flares in hard x rays HXIS employs a grid collimator with an 8-sec of arc FWHM angular resolution. The collimator consists of ten grid plates in a sequence. The position accuracy of the grids in their planes must be better than a few microns. This paper describes a simple optical alignment method developed to perform measurements of the grid positions with a precision of 1 microm.