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1.
BMC Neurol ; 23(1): 122, 2023 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-36973718

RESUMO

BACKGROUND: Migraine is a common and distressing neurological condition characterised by recurrent throbbing headaches, nausea and heightened sensitivity to light and sound. Accumulating evidence suggests that cerebral arteries dilate during migraine, causing distal microvessels to constrict, which could activate nociceptors and cause onset of headache pain. If so, preventing or attenuating chronic microvascular constriction, and promoting a dilatory phenotype, may reduce frequency and/or severity of migraines. The primary aim of the L-Arginine and Aged Garlic Extract (LARGE) trial is to investigate whether oral treatment with dietary nutraceuticals, L-arginine and aged garlic extract (AGE), both systemic vasodilatory agents, will alleviate migraine frequency, duration and severity in adults with chronic frequent episodic migraines. METHODS: The study is a randomised double-blind placebo-controlled phase-II single-site clinical trial conducted in Perth, Australia. The target sample is to recruit 240 participants diagnosed with chronic frequent episodic migraines between 18 and 80 years of age. Participants will be randomised to one of four treatment groups for 14 weeks (placebo induction for 2 weeks, followed by 12 weeks on one of the respective treatment arms): placebo, L-arginine, AGE, or a combination of L-arginine and AGE. The doses of L-arginine and AGE are 1.5 g and 1 g daily, respectively. The primary outcome is to assess migraine response using change in migraine frequency and intensity between baseline and 12 weeks. Secondary outcomes include the impact of L-arginine and/or AGE on photosensitivity, retinal vessel changes, and blood biomarker concentrations of vascular tone, following a 12-week intervention. DISCUSSION: The protocol describes the oral administration of 2 nutraceutical-based interventions as possible prophylactic treatments for chronic frequent episodic migraines, with potential for direct clinical translation of outcomes. Potential limitations of the study include the fixed-dose design of each treatment arm and that in vivo neuroimaging methods, such as magnetic resonance imaging (MRI), will not be conducted to determine putative cerebro-vasodilatory changes to coincide with the outcome measures. Dose-response studies may be indicated. TRIAL REGISTRATION: The trial was retrospectively registered with the Australian New Zealand Clinical Trials Registry ACTRN12621001476820 (Universal Trial Number: U1111-1268-1117) on 04/08/2021. This is protocol version 1, submitted on 25/11/2022.


Assuntos
Alho , Transtornos de Enxaqueca , Resultado do Tratamento , Austrália/epidemiologia , Transtornos de Enxaqueca/tratamento farmacológico , Transtornos de Enxaqueca/prevenção & controle , Transtornos de Enxaqueca/diagnóstico , Cefaleia , Método Duplo-Cego , Ensaios Clínicos Controlados Aleatórios como Assunto , Ensaios Clínicos Fase II como Assunto
2.
Ann Bot ; 130(3): 383-392, 2022 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-35259242

RESUMO

BACKGROUND AND AIMS: While trait-based approaches have provided critical insights into general plant functioning, we lack a comprehensive quantitative view on plant strategies in flooded conditions. Plants adapted to flooded conditions have specific traits (e.g. root porosity, low root/shoot ratio and shoot elongation) to cope with the environmental stressors including anoxic sediments, and the subsequent presence of phytotoxic compounds. In flooded habitats, plants also respond to potential nutrient and light limitations, e.g. through the expression of leaf economics traits and size-related traits, respectively. However, we do not know whether and how these trait dimensions are connected. METHODS: Based on a trait dataset compiled on 131 plant species from 141 studies in flooded habitats, we quantitatively analysed how flooding-induced traits are positioned in relation to the other two dominant trait dimensions: leaf economics traits and size-related traits. We evaluated how these key trait components are expressed along wetness gradients, across habitat types and among plant life forms. KEY RESULTS: We found that flooding-induced traits constitute a trait dimension independent from leaf economics traits and size-related traits, indicating that there is no generic trade-off associated with flooding adaptations. Moreover, individual flooding-induced traits themselves are to a large extent decoupled from each other. These results suggest that adaptation to stressful environments, such as flooding, can be stressor specific without generic adverse effects on plant functioning (e.g. causing trade-offs on leaf economics traits). CONCLUSIONS: The trait expression across multiple dimensions promotes plant adaptations and coexistence across multifaceted flooded environments. The decoupled trait dimensions, as related to different environmental drivers, also explain why ecosystem functioning (including, for example, methane emissions) are species and habitat specific. Thus, our results provide a backbone for applying trait-based approaches in wetland ecology by considering flooding-induced traits as an independent trait dimension.


Assuntos
Ecossistema , Inundações , Metano , Folhas de Planta , Fenômenos Fisiológicos Vegetais , Plantas/genética
3.
Pain Med ; 21(6): 1199-1207, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31120123

RESUMO

OBJECTIVE: Studies in rodents suggest that cutaneous beta-2 adrenoceptors (ß2-ARs) mediate inflammation and pain after tissue injury and that inflammation and peripheral nerve injury trigger increases in neuronal ß2-AR expression. Hence, the aim of this study was to investigate the expression of ß2-ARs on keratinocytes and dermal nerves in patients with complex regional pain syndrome (CRPS). DESIGN, SETTING, AND SUBJECTS: Fifty-eight patients with CRPS were recruited for this study. In addition, skin biopsies were obtained from 13 pain-free women and three pain-free men of similar age and sex distribution as the patients. METHODS: Quantitative sensory tests for assessing sensitivity to pressure, pinprick, light touch, heat, and cold were administered, and skin biopsies were obtained from the affected and contralateral limbs. Skin biopsies were also obtained from a similar site on the dorsal hand or foot of pain-free controls. Immunohistochemistry and confocal microscopy were used to identify ß2-ARs on keratinocytes, dermal nerves, and blood vessels in the skin samples. RESULTS: The distribution of ß2-ARs in keratinocytes and nerves was similar in the affected and contralateral limbs of patients and was similar for target cells in patients and controls. However, elevated ß2-AR expression in reticular nerve bundles was associated with heightened sensitivity to heat pain. CONCLUSIONS: These findings do not support a major role of cutaneous ß2-ARs in CRPS. However, activation of neuronal ß2-ARs may contribute to thermal hyperalgesia in a subgroup of patients. Whether activation of ß2-ARs on keratinocytes mediates inflammation early in the course of CRPS requires further investigation.


Assuntos
Síndromes da Dor Regional Complexa , Receptores Adrenérgicos beta 2 , Estudos de Casos e Controles , Humanos , Hiperalgesia , Dor , Pele
4.
Pain Pract ; 20(7): 737-747, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32306462

RESUMO

OBJECTIVE: To investigate the preventive effects of a combined antioxidant drug (N-acetylcysteine, vitamin E, and vitamin C [NEC]) on migraine outcomes. Migraine is characterized by increased oxidative stress and neurogenic inflammation in the brain; therefore, antioxidants may have a migraine preventive effect. DESIGN: Randomized, double-blind, sham-controlled pilot study. SETTING: Australian community. SUBJECTS: Adults reporting 2 to 8 migraines per month for at least a year. METHODS: After a 1-month baseline period, 35 subjects completed 3 months of treatment with NEC (n = 19) or sham (n = 16) capsules. The primary outcome was the difference in mean number of headaches per month between baseline and final month of the trial for NEC and sham groups; secondary outcomes are listed below. RESULTS: For NEC there was a significant decrease in mean number of headaches by 3.0 per month (P = 0.004) compared with 1.4 for sham (P = 0.073); there was no significant difference in these changes between the 2 groups (P = 0.052). Average monthly headache (P = 0.041) and migraine frequency (P = 0.018) were significantly less for NEC vs. sham. In NEC subjects, there was a significant decrease in average monthly migraine days (-3.1), moderate/severe headache days (-3.2), migraine duration, headache pain scores, and acute headache medication use. CONCLUSIONS: This is the first randomized controlled trial to find that combined antioxidant therapy with NEC reduces headaches and migraines in adult migraineurs. Given the limitations of this pilot study, an adequately powered randomized controlled trial is planned to further investigate antioxidant prophylaxis in migraine.


Assuntos
Acetilcisteína/uso terapêutico , Antioxidantes/uso terapêutico , Ácido Ascórbico/uso terapêutico , Transtornos de Enxaqueca/prevenção & controle , Vitamina E/uso terapêutico , Adulto , Idoso , Austrália , Método Duplo-Cego , Quimioterapia Combinada/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Resultado do Tratamento
5.
Glob Chang Biol ; 25(4): 1358-1367, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30638293

RESUMO

Climate change will have large consequences for flooding frequencies in freshwater systems. In interaction with anthropogenic activities (flow regulation, channel restoration and catchment land-use) this will both increase flooding and drought across the world. Like in many other ecosystems facing changed environmental conditions, it remains difficult to predict the rate and trajectory of vegetation responses to changed conditions. Given that critical ecosystem services (e.g. bank stabilization, carbon subsidies to aquatic communities or water purification) depend on riparian vegetation composition, it is important to understand how and how fast riparian vegetation responds to changing flooding regimes. We studied vegetation changes over 19 growing seasons in turfs that were transplanted in a full-factorial design between three riparian elevations with different flooding frequencies. We found that (a) some transplanted communities may have developed into an alternative stable state and were still different from the target community, and (b) pathways of vegetation change were highly directional but alternative trajectories did occur, (c) changes were rather linear but faster when flooding frequencies increased than when they decreased, and (d) we observed fastest changes in turfs when proxies for mortality and colonization were highest. These results provide rare examples of alternative transient trajectories and stable states under field conditions, which is an important step towards understanding their drivers and their frequency in a changing world.

6.
Oecologia ; 191(1): 177-190, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31401664

RESUMO

Global climate models predict more frequent periods of drought stress alternated by heavier, but fewer rainfall events in the future. Biodiversity studies have shown that such changed drought stress may be mitigated by plant species richness. Here, we investigate if grassland communities, differing in species richness, respond differently to climatic extremes within the growing season. In a 3-year outdoor mesocosm experiment, four grassland species in both monoculture and mixture were subjected to a rainfall distribution regime with two levels: periods of severe drought in the summer intermitted by extreme rainfall events versus regular rainfall over time. Both treatments received the same amount of water over the season. Extreme rainfall combined with drought periods resulted in a 15% decrease in aboveground biomass in the second and third year, compared to the regular rainfall regime. Root biomass was also reduced in the extreme rainfall treatment, particularly in the top soil layer (- 40%). All species developed higher water use efficiencies (less negative leaf δ13C) in extreme rainfall than in regular rainfall. These responses to the rainfall/drought treatment were independent of species richness, although the mixtures were on an average more productive in terms of biomass than the monocultures. Our experimental results suggest that mixtures are similarly able to buffer these within-season rainfall extremes than monocultures, which contrasts with findings in the studies on natural droughts. Our work demonstrates the importance of investigating the interactions between rainfall distribution and drought periods for understanding effects of climate change on plant community performance.


Assuntos
Secas , Pradaria , Biodiversidade , Biomassa , Mudança Climática , Plantas
7.
BMC Med Educ ; 18(1): 110, 2018 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-29751806

RESUMO

BACKGROUND: The objective of pain medicine education is to provide medical students with opportunities to develop their knowledge, skills and professional attitudes that will lead to their becoming safe, capable, and compassionate medical practitioners who are able to meet the healthcare needs of persons in pain. This study was undertaken to identify and describe the delivery of pain medicine education at medical schools in Australia and New Zealand. METHOD: All 23 medical schools in Australia and New Zealand in 2016 were included in this study. A structured curriculum audit tool was used to obtain information on pain medicine curricula including content, delivery, teaching and assessment methods. RESULTS: Nineteen medical schools (83%) completed the curriculum audit. Neurophysiology, clinical assessment, analgesia use and multidimensional aspects of pain medicine were covered by most medical schools. Specific learning objectives for pain medicine were not identified by 42% of medical schools. One medical school offered a dedicated pain medicine module delivered over 1 week. Pain medicine teaching was delivered at all schools by a number of different departments throughout the curriculum. Interprofessional learning (IPL) in the context of pain medicine education was not specified by any of the medical schools. The mean time allocated for pain medicine teaching over the entire medical course was just under 20 h. The objective structured clinical examination (OSCE) was used by 32% of schools to assess knowledge and skills in pain medicine. 16% of schools were unsure of whether any assessment of pain medicine education took place. CONCLUSION: This descriptive study provides important baseline information for pain medicine education at medical schools in Australia and New Zealand. Medical schools do not have well-documented or comprehensive pain curricula that are delivered and assessed using pedagogically-sound approaches considering the complexity of the topic, the prevalence and public health burden of pain.


Assuntos
Analgesia , Analgésicos/uso terapêutico , Currículo , Educação de Graduação em Medicina , Manejo da Dor , Faculdades de Medicina , Austrália , Feminino , Humanos , Masculino , Nova Zelândia , Dor/tratamento farmacológico , Faculdades de Medicina/estatística & dados numéricos , Estudantes de Medicina , Ensino , Fatores de Tempo
8.
Radiology ; 283(2): 547-559, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27846378

RESUMO

Purpose To assess whether dynamic fluorine 18 (18F) fluorodeoxyglucose (FDG) positron emission tomography (PET) has added value over static 18F-FDG PET for tumor delineation in non-small cell lung cancer (NSCLC) radiation therapy planning by using pathology volumes as the reference standard and to compare pharmacokinetic rate constants of 18F-FDG metabolism, including regional variation, between NSCLC histologic subtypes. Materials and Methods The study was approved by the institutional review board. Patients gave written informed consent. In this prospective observational study, 1-hour dynamic 18F-FDG PET/computed tomographic examinations were performed in 35 patients (36 resectable NSCLCs) between 2009 and 2014. Static and parametric images of glucose metabolic rate were obtained to determine lesion volumes by using three delineation strategies. Pathology volume was calculated from three orthogonal dimensions (n = 32). Whole tumor and regional rate constants and blood volume fraction (VB) were computed by using compartment modeling. Results Pathology volumes were larger than PET volumes (median difference, 8.7-25.2 cm3; Wilcoxon signed rank test, P < .001). Static fuzzy locally adaptive Bayesian (FLAB) volumes corresponded best with pathology volumes (intraclass correlation coefficient, 0.72; P < .001). Bland-Altman analyses showed the highest precision and accuracy for static FLAB volumes. Glucose metabolic rate and 18F-FDG phosphorylation rate were higher in squamous cell carcinoma (SCC) than in adenocarcinoma (AC), whereas VB was lower (Mann-Whitney U test or t test, P = .003, P = .036, and P = .019, respectively). Glucose metabolic rate, 18F-FDG phosphorylation rate, and VB were less heterogeneous in AC than in SCC (Friedman analysis of variance). Conclusion Parametric images are not superior to static images for NSCLC delineation. FLAB-based segmentation on static 18F-FDG PET images is in best agreement with pathology volume and could be useful for NSCLC autocontouring. Differences in glycolytic rate and VB between SCC and AC are relevant for research in targeting agents and radiation therapy dose escalation. © RSNA, 2016 Online supplemental material is available for this article.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Fluordesoxiglucose F18/farmacocinética , Glucose/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Neoplasias Pulmonares/diagnóstico por imagem , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Imagem Molecular/métodos , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/farmacocinética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
9.
New Phytol ; 213(2): 645-656, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27717024

RESUMO

Flooding is expected to increase in frequency and severity in the future. The ecological consequences of flooding are the combined result of species-specific plant traits and ecological context. However, the majority of past flooding research has focused on individual model species under highly controlled conditions. An early summer flooding event in a grassland biodiversity experiment in Jena, Germany, provided the opportunity to assess flooding responses of 60 grassland species in monocultures and 16-species mixtures. We examined plant biomass, species-specific traits (plant height, specific leaf area (SLA), root aerenchyma, starch content) and soil porosity. We found that, on average, plant species were less negatively affected by the flood when grown in higher-diversity plots in July 2013. By September 2013, grasses were unaffected by the flood regardless of plant diversity, and legumes were severely negatively affected regardless of plant diversity. Plants with greater SLA and more root aerenchyma performed better in September. Soil porosity was higher in higher-diversity plots and had a positive effect on plant performance. As floods become more frequent and severe in the future, growing flood-sensitive plants in higher-diversity communities and in soil with greater soil aeration may attenuate the most negative effects of flooding.


Assuntos
Inundações , Desenvolvimento Vegetal , Biomassa , Folhas de Planta/anatomia & histologia , Porosidade , Característica Quantitativa Herdável , Solo , Especificidade da Espécie
10.
Plant Physiol ; 170(4): 2351-64, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-26850278

RESUMO

Soil flooding is a common stress factor affecting plants. To sustain root function in the hypoxic environment, flooding-tolerant plants may form new, aerenchymatous adventitious roots (ARs), originating from preformed, dormant primordia on the stem. We investigated the signaling pathway behind AR primordium reactivation in the dicot species Solanum dulcamara Transcriptome analysis indicated that flooding imposes a state of quiescence on the stem tissue, while increasing cellular activity in the AR primordia. Flooding led to ethylene accumulation in the lower stem region and subsequently to a drop in abscisic acid (ABA) level in both stem and AR primordia tissue. Whereas ABA treatment prevented activation of AR primordia by flooding, inhibition of ABA synthesis was sufficient to activate them in absence of flooding. Together, this reveals that there is a highly tissue-specific response to reduced ABA levels. The central role for ABA in the response differentiates the pathway identified here from the AR emergence pathway known from rice (Oryza sativa). Flooding and ethylene treatment also induced expression of the polar auxin transporter PIN2, and silencing of this gene or chemical inhibition of auxin transport inhibited primordium activation, even though ABA levels were reduced. Auxin treatment, however, was not sufficient for AR emergence, indicating that the auxin pathway acts in parallel with the requirement for ABA reduction. In conclusion, adaptation of S. dulcamara to wet habitats involved co-option of a hormonal signaling cascade well known to regulate shoot growth responses, to direct a root developmental program upon soil flooding.


Assuntos
Inundações , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/metabolismo , Solanum/metabolismo , Ácido Abscísico/metabolismo , Transporte Biológico/efeitos dos fármacos , Etilenos/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácidos Indolacéticos/metabolismo , Especificidade de Órgãos/efeitos dos fármacos , Especificidade de Órgãos/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Solanum/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , Transcriptoma/genética
11.
Eur J Nucl Med Mol Imaging ; 44(Suppl 1): 4-16, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28687866

RESUMO

In recent years, there have been multiple advances in positron emission tomography/computed tomography (PET/CT) that improve cancer imaging. The present generation of PET/CT scanners introduces new hardware, software, and acquisition methods. This review describes these new developments, which include time-of-flight (TOF), point-spread-function (PSF), maximum-a-posteriori (MAP) based reconstruction, smaller voxels, respiratory gating, metal artefact reduction, and administration of quadratic weight-dependent 18F-fluorodeoxyglucose (FDG) activity. Also, hardware developments such as continuous bed motion (CBM), (digital) solid-state photodetectors and combined PET and magnetic resonance (MR) systems are explained. These novel techniques have a significant impact on cancer imaging, as they result in better image quality, improved small lesion detectability, and more accurate quantification of radiopharmaceutical uptake. This influences cancer diagnosis and staging, as well as therapy response monitoring and radiotherapy planning. Finally, the possible impact of these developments on the European Association of Nuclear Medicine (EANM) guidelines and EANM Research Ltd. (EARL) accreditation for FDG-PET/CT tumor imaging is discussed.


Assuntos
Tomografia por Emissão de Pósitrons/métodos , Artefatos , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Imagem Multimodal
12.
Ann Bot ; 120(1): 171-180, 2017 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-28586427

RESUMO

Background and Aims: Temporal flooding is a common environmental stress for terrestrial plants. Aquatic adventitious roots (aquatic roots) are commonly formed in flooding-tolerant plant species and are generally assumed to be beneficial for plant growth by supporting water and nutrient uptake during partial flooding. However, the actual contribution of these roots to plant performance under flooding has hardly been quantified. As the investment into aquatic root development in terms of carbohydrates may be costly, these costs may - depending on the specific environmental conditions - offset the beneficial effects of aquatic roots. This study tested the hypothesis that the balance between potential costs and benefits depends on the duration of flooding, as the benefits are expected to outweigh the costs in long-term but not in short-term flooding. Methods: The contribution of aquatic roots to plant performance was tested in Solanum dulcamara during 1-4 weeks of partial submergence and by experimentally manipulating root production. Nutrient uptake by aquatic roots, transpiration and photosynthesis were measured in plants differing in aquatic root development to assess the specific function of these roots. Key Results: As predicted, flooded plants benefited from the presence of aquatic roots. The results showed that this was probably due to the contribution of roots to resource uptake. However, these beneficial effects were only present in long-term but not in short-term flooding. This relationship could be explained by the correlation between nutrient uptake and the flooding duration-dependent size of the aquatic root system. Conclusions: The results indicate that aquatic root formation is likely to be selected for in habitats characterized by long-term flooding. This study also revealed only limited costs associated with adventitious root formation, which may explain the maintenance of the ability to produce aquatic roots in habitats characterized by very rare or short flooding events.


Assuntos
Inundações , Raízes de Plantas/fisiologia , Solanum/fisiologia , Água/fisiologia , Ecossistema , Fotossíntese , Transpiração Vegetal
13.
New Phytol ; 211(4): 1159-69, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27174359

RESUMO

Contents 1159 I. 1159 II. 1161 III. 1164 IV. 1166 1167 References 1167 SUMMARY: The search for a root economics spectrum (RES) has been sparked by recent interest in trait-based plant ecology. By analogy with the one-dimensional leaf economics spectrum (LES), fine-root traits are hypothesised to match leaf traits which are coordinated along one axis from resource acquisitive to conservative traits. However, our literature review and meta-level analysis reveal no consistent evidence of an RES mirroring an LES. Instead the RES appears to be multidimensional. We discuss three fundamental differences contributing to the discrepancy between these spectra. First, root traits are simultaneously constrained by various environmental drivers not necessarily related to resource uptake. Second, above- and belowground traits cannot be considered analogues, because they function differently and might not be related to resource uptake in a similar manner. Third, mycorrhizal interactions may offset selection for an RES. Understanding and explaining the belowground mechanisms and trade-offs that drive variation in root traits, resource acquisition and plant performance across species, thus requires a fundamentally different approach than applied aboveground. We therefore call for studies that can functionally incorporate the root traits involved in resource uptake, the complex soil environment and the various soil resource uptake mechanisms - particularly the mycorrhizal pathway - in a multidimensional root trait framework.


Assuntos
Raízes de Plantas/fisiologia , Característica Quantitativa Herdável , Árvores/fisiologia , Micorrizas/fisiologia , Folhas de Planta/fisiologia
14.
Plant Physiol ; 167(4): 1616-29, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25667318

RESUMO

Plants respond to reductions in internal oxygen concentrations with adaptive mechanisms (for example, modifications of metabolism to cope with reduced supply of ATP). These responses are, at the transcriptional level, mediated by the group VII Ethylene Response Factor transcription factors, which have stability that is regulated by the N-end rule pathway of protein degradation. N-end rule pathway mutants are characterized by a constitutive expression of hypoxia response genes and abscisic acid hypersensitivity. Here, we identify a novel proteolysis6 (prt6) mutant allele, named greening after extended darkness1 (ged1), which was previously discovered in a screen for genomes uncoupled-like mutants and shows the ability to withstand long periods of darkness at the seedling stage. Interestingly, this ethyl methanesulfonate-derived mutant shows unusual chromosomal rearrangement instead of a point mutation. Furthermore, the sensitivity of N-end rule pathway mutants ged1 and prt6-1 to submergence was studied in more detail to understand previously contradicting experiments on this topic. Finally, it was shown that mutants for the N-end rule pathway are generally more tolerant to starvation conditions, such as prolonged darkness or submergence, which was partially associated with carbohydrate conservation.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas , Oxigênio/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ácido Abscísico/metabolismo , Aclimatação , Alelos , Arabidopsis/genética , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Mapeamento Cromossômico , Escuridão , Etilenos/metabolismo , Imersão , Mutação , Proteólise , Plântula/genética , Plântula/fisiologia , Plântula/efeitos da radiação , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/genética
15.
Plant Cell Environ ; 39(7): 1537-48, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26846194

RESUMO

Traits for survival during flooding of terrestrial plants include stimulation or inhibition of shoot elongation, aerenchyma formation and efficient gas exchange. Leaf gas films form on superhydrophobic cuticles during submergence and enhance underwater gas exchange. The main hypothesis tested was that the presence of leaf gas films influences the distribution of plant species along a natural flood gradient. We conducted laboratory experiments and field observations on species distributed along a natural flood gradient. We measured presence or absence of leaf gas films and specific leaf area of 95 species. We also measured, gas film retention time during submergence and underwater net photosynthesis and dark respiration of 25 target species. The presence of a leaf gas film was inversely correlated to flood frequency and duration and reached a maximum value of 80% of the species in the rarely flooded locations. This relationship was primarily driven by grasses that all, independently of their field location along the flood gradient, possess gas films when submerged. Although the present study and earlier experiments have shown that leaf gas films enhance gas exchange of submerged plants, the ability of species to form leaf gas films did not show the hypothesized relationship with species composition along the flood gradient.


Assuntos
Ecossistema , Inundações , Gases/metabolismo , Folhas de Planta/metabolismo , Respiração Celular , Países Baixos , Fotossíntese , Rios
16.
Plant Cell Environ ; 39(7): 1485-99, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26759219

RESUMO

In the field, biotic and abiotic stresses frequently co-occur. As a consequence, common molecular signalling pathways governing adaptive responses to individual stresses can interact, resulting in compromised phenotypes. How plant signalling pathways interact under combined stresses is poorly understood. To assess this, we studied the consequence of drought and soil flooding on resistance of Solanum dulcamara to Spodoptera exigua and their effects on hormonal and transcriptomic profiles. The results showed that S. exigua larvae performed less well on drought-stressed plants than on well-watered and flooded plants. Both drought and insect feeding increased abscisic acid and jasmonic acid (JA) levels, whereas flooding did not induce JA accumulation. RNA sequencing analyses corroborated this pattern: drought and herbivory induced many biological processes that were repressed by flooding. When applied in combination, drought and herbivory had an additive effect on specific processes involved in secondary metabolism and defence responses, including protease inhibitor activity. In conclusion, drought and flooding have distinct effects on herbivore-induced responses and resistance. Especially, the interaction between abscisic acid and JA signalling may be important to optimize plant responses to combined drought and insect herbivory, making drought-stressed plants more resistant to insects than well-watered and flooded plants.


Assuntos
Secas , Inundações , Herbivoria , Solanum/metabolismo , Estresse Fisiológico , Ácido Abscísico/metabolismo , Animais , Ciclopentanos/metabolismo , Etilenos/metabolismo , Insetos , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo
17.
Plant Cell ; 25(11): 4691-707, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24285788

RESUMO

Global climate change has increased flooding events, which affect both natural vegetation dynamics and crop productivity. The flooded environment is lethal for most plant species because it restricts gas exchange and induces an energy and carbon crisis. Flooding survival strategies have been studied in Oryza sativa, a cultivated monocot. However, our understanding of plant adaptation to natural flood-prone environments remains scant, even though wild plants represent a valuable resource of tolerance mechanisms that could be used to generate stress-tolerant crops. Here we identify mechanisms that mediate the distinct flooding survival strategies of two related wild dicot species: Rumex palustris and Rumex acetosa. Whole transcriptome sequencing and metabolite profiling reveal flooding-induced metabolic reprogramming specific to R. acetosa. By contrast, R. palustris uses the early flooding signal ethylene to increase survival by regulating shade avoidance and photomorphogenesis genes to outgrow submergence and by priming submerged plants for future low oxygen stress. These results provide molecular resolution of flooding survival strategies of two species occupying distinct hydrological niches. Learning how these contrasting flood adaptive strategies evolved in nature will be instrumental for the development of stress-tolerant crop varieties that deliver enhanced yields in a changing climate.


Assuntos
Adaptação Fisiológica , Inundações , Regulação da Expressão Gênica de Plantas , Rumex/fisiologia , Carbono/metabolismo , Ecossistema , Etilenos/metabolismo , Perfilação da Expressão Gênica , Homeostase , Íons/metabolismo , Luz , Redes e Vias Metabólicas , Oxigênio/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Rumex/genética , Rumex/crescimento & desenvolvimento , Rumex/metabolismo , Estresse Fisiológico
18.
Pain Pract ; 16(1): 31-7, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25469881

RESUMO

The aim of this study was to investigate the hypothesis that chronic widespread pain, (CWP) drawn by patients on a body diagram, could be used as a screening tool for increased pain sensitization, psycho-social load, and utilization of pain management strategies. The triage questionnaires of 144 adults attending a chronic pain outpatients' clinic were audited and the percentage pain surface area (PPSA) drawn on their body diagrams was calculated using the "rule of nines" (RON) method for burns area assessment. Outcomes were measured using the painDETECT Questionnaire (PD-Q) and other indices and compared using a nonrandomized, case-control method. It was found that significantly more subjects with CWP (defined as a PPSA ≥ 20%) reported high (≥ 19) PD-Q scores (suggesting pain "sensitization" or neuropathic pain) (P = 0.0002), "severe" or "extremely severe" anxiety scores on the Depression, Anxiety and Stress Scale-21 Items Questionnaire (P = 0.0270), ≥ 5 psycho-social stressors (P = 0.0022), ≥ 5 significant life events (P = 0.0098), and used ≥ 7 pain management strategies (PMS) (P < 00001), compared to control subjects with a lower PPSA. A Widespread Pain Index score ≥ 7 (OR = 11.36), PD-Q score ≥ 19 (OR = 4.46) and use of ≥ 7 PMS (OR = 5.49) were independently associated with CWP. This study demonstrates that calculating PPSA on a body diagram (using the RON method) is a valid and convenient "snapshot" screening tool to identify patients with an increased likelihood of pain sensitization, psycho-social load, and utilizing pain management resources.


Assuntos
Dor Crônica/diagnóstico , Dor Crônica/psicologia , Manejo da Dor/métodos , Medição da Dor/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Ansiedade/psicologia , Estudos de Casos e Controles , Feminino , Fibromialgia/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Neuralgia/diagnóstico , Limiar da Dor , Meio Social , Estresse Psicológico/diagnóstico , Estresse Psicológico/psicologia , Inquéritos e Questionários , Triagem , Adulto Jovem
19.
J Exp Bot ; 66(18): 5507-17, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26105997

RESUMO

The plant's root system is highly plastic, and can respond to environmental stimuli such as high nitrogen (N) in patches. A root may respond to an N patch by selective placement of new lateral roots, and therewith increases root N uptake. This may be a desirable trait in breeding programmes, since it decreases NO3(-) leaching and N2O emission. Roots of maize (Zea mays L.) were grown without N in split-nutrient rhizoslides. One side of the slides was exposed to high N after 15 d of root development, and root elongation was measured for another 15 d, described in a time course model and parameterized. The elongation rates of crown axile roots on the N-treated side of the plant followed a logistic increase to a maximum of 5.3cm d(-1); 95% of the maximum were reached within 4 d. At the same time, on the untreated side, axile root elongation dropped linearly to 1.2cm d(-1) within 6.4 d and stayed constant thereafter. Twice as many lateral roots were formed on the crown axis on the N side compared to the untreated side. Most strikingly, the elongation rates of laterals of the N side increased linearly with most of the roots reaching an asymptote ~8 d after start of the N treatment. By contrast, laterals on the side without N did not show any detectable elongation beyond the first day after their emergence. We conclude that split-nutrient rhizoslides have great potential to improve our knowledge about nitrogen responsiveness and selection for contrasting genotypes.


Assuntos
Nitrogênio/metabolismo , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Modelos Biológicos , Fenótipo , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Zea mays/genética
20.
Eur J Nucl Med Mol Imaging ; 42(2): 328-54, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25452219

RESUMO

The purpose of these guidelines is to assist physicians in recommending, performing, interpreting and reporting the results of FDG PET/CT for oncological imaging of adult patients. PET is a quantitative imaging technique and therefore requires a common quality control (QC)/quality assurance (QA) procedure to maintain the accuracy and precision of quantitation. Repeatability and reproducibility are two essential requirements for any quantitative measurement and/or imaging biomarker. Repeatability relates to the uncertainty in obtaining the same result in the same patient when he or she is examined more than once on the same system. However, imaging biomarkers should also have adequate reproducibility, i.e. the ability to yield the same result in the same patient when that patient is examined on different systems and at different imaging sites. Adequate repeatability and reproducibility are essential for the clinical management of patients and the use of FDG PET/CT within multicentre trials. A common standardised imaging procedure will help promote the appropriate use of FDG PET/CT imaging and increase the value of publications and, therefore, their contribution to evidence-based medicine. Moreover, consistency in numerical values between platforms and institutes that acquire the data will potentially enhance the role of semiquantitative and quantitative image interpretation. Precision and accuracy are additionally important as FDG PET/CT is used to evaluate tumour response as well as for diagnosis, prognosis and staging. Therefore both the previous and these new guidelines specifically aim to achieve standardised uptake value harmonisation in multicentre settings.


Assuntos
Fluordesoxiglucose F18 , Imagem Multimodal/métodos , Neoplasias/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos , Tomografia Computadorizada por Raios X/métodos , Humanos
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