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1.
Mol Cell ; 81(21): 4509-4526.e10, 2021 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-34560002

RESUMO

The interferon (IFN) pathway is critical for cytotoxic T cell activation, which is central to tumor immunosurveillance and successful immunotherapy. We demonstrate here that PKCλ/ι inactivation results in the hyper-stimulation of the IFN cascade and the enhanced recruitment of CD8+ T cells that impaired the growth of intestinal tumors. PKCλ/ι directly phosphorylates and represses the activity of ULK2, promoting its degradation through an endosomal microautophagy-driven ubiquitin-dependent mechanism. Loss of PKCλ/ι results in increased levels of enzymatically active ULK2, which, by direct phosphorylation, activates TBK1 to foster the activation of the STING-mediated IFN response. PKCλ/ι inactivation also triggers autophagy, which prevents STING degradation by chaperone-mediated autophagy. Thus, PKCλ/ι is a hub regulating the IFN pathway and three autophagic mechanisms that serve to maintain its homeostatic control. Importantly, single-cell multiplex imaging and bioinformatics analysis demonstrated that low PKCλ/ι levels correlate with enhanced IFN signaling and good prognosis in colorectal cancer patients.


Assuntos
Neoplasias Colorretais/metabolismo , Interferons/metabolismo , Isoenzimas/metabolismo , Proteína Quinase C/metabolismo , Proteínas Serina-Treonina Quinases/fisiologia , Transdução de Sinais , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Autofagia , Linfócitos T CD8-Positivos/metabolismo , Carcinogênese , Transformação Celular Neoplásica , Neoplasias Colorretais/mortalidade , Cicloeximida/química , Feminino , Células HEK293 , Humanos , Imunofenotipagem , Fator Regulador 3 de Interferon/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Pessoa de Meia-Idade , Transplante de Neoplasias , Fosforilação , Prognóstico , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Fatores de Transcrição , Regulação para Cima
2.
Cardiovasc Diabetol ; 22(1): 44, 2023 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-36870961

RESUMO

BACKGROUND: Obesity is a negative chronic metabolic health condition that represents an additional risk for the development of multiple pathologies. Epidemiological studies have shown how maternal obesity or gestational diabetes mellitus during pregnancy constitute serious risk factors in relation to the appearance of cardiometabolic diseases in the offspring. Furthermore, epigenetic remodelling may help explain the molecular mechanisms that underlie these epidemiological findings. Thus, in this study we explored the DNA methylation landscape of children born to mothers with obesity and gestational diabetes during their first year of life. METHODS: We used Illumina Infinium MethylationEPIC BeadChip arrays to profile more than 770,000 genome-wide CpG sites in blood samples from a paediatric longitudinal cohort consisting of 26 children born to mothers who suffered from obesity or obesity with gestational diabetes mellitus during pregnancy and 13 healthy controls (measurements taken at 0, 6 and 12 month; total N = 90). We carried out cross-sectional and longitudinal analyses to derive DNA methylation alterations associated with developmental and pathology-related epigenomics. RESULTS: We identified abundant DNA methylation changes during child development from birth to 6 months and, to a lesser extent, up to 12 months of age. Using cross-sectional analyses, we discovered DNA methylation biomarkers maintained across the first year of life that could discriminate children born to mothers who suffered from obesity or obesity with gestational diabetes. Importantly, enrichment analyses suggested that these alterations constitute epigenetic signatures that affect genes and pathways involved in the metabolism of fatty acids, postnatal developmental processes and mitochondrial bioenergetics, such as CPT1B, SLC38A4, SLC35F3 and FN3K. Finally, we observed evidence of an interaction between developmental DNA methylation changes and maternal metabolic condition alterations. CONCLUSIONS: Our observations highlight the first six months of development as being the most crucial for epigenetic remodelling. Furthermore, our results support the existence of systemic intrauterine foetal programming linked to obesity and gestational diabetes that affects the childhood methylome beyond birth, which involves alterations related to metabolic pathways, and which may interact with ordinary postnatal development programmes.


Assuntos
Diabetes Gestacional , Obesidade Materna , Gravidez , Humanos , Feminino , Criança , Epigenoma , Estudos Transversais , Epigenômica , Obesidade , Epigênese Genética
3.
Proc Natl Acad Sci U S A ; 117(47): 29720-29729, 2020 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-33139533

RESUMO

Forest vulnerability to drought is expected to increase under anthropogenic climate change, and drought-induced mortality and community dynamics following drought have major ecological and societal impacts. Here, we show that tree mortality concomitant with drought has led to short-term (mean 5 y, range 1 to 23 y after mortality) vegetation-type conversion in multiple biomes across the world (131 sites). Self-replacement of the dominant tree species was only prevalent in 21% of the examined cases and forests and woodlands shifted to nonwoody vegetation in 10% of them. The ultimate temporal persistence of such changes remains unknown but, given the key role of biological legacies in long-term ecological succession, this emerging picture of postdrought ecological trajectories highlights the potential for major ecosystem reorganization in the coming decades. Community changes were less pronounced under wetter postmortality conditions. Replacement was also influenced by management intensity, and postdrought shrub dominance was higher when pathogens acted as codrivers of tree mortality. Early change in community composition indicates that forests dominated by mesic species generally shifted toward more xeric communities, with replacing tree and shrub species exhibiting drier bioclimatic optima and distribution ranges. However, shifts toward more mesic communities also occurred and multiple pathways of forest replacement were observed for some species. Drought characteristics, species-specific environmental preferences, plant traits, and ecosystem legacies govern postdrought species turnover and subsequent ecological trajectories, with potential far-reaching implications for forest biodiversity and ecosystem services.


Assuntos
Secas/mortalidade , Florestas , Biodiversidade , Mudança Climática/mortalidade , Ecossistema , Especificidade da Espécie , Árvores/fisiologia
4.
Int J Mol Sci ; 24(15)2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37569678

RESUMO

Pseudomonas aeruginosa is a ubiquitous nosocomial opportunistic pathogen that harbors many virulence determinants. Part of P. aeruginosa success colonizing a variety of habitats resides in its metabolic robustness and plasticity, which are the basis of its capability of adaptation to different nutrient sources and ecological conditions, including the infected host. Given this situation, it is conceivable that P. aeruginosa virulence might be, at least in part, under metabolic control, in such a way that virulence determinants are produced just when needed. Indeed, it has been shown that the catabolite repression control protein Crc, which together with the RNA chaperon Hfq regulates the P. aeruginosa utilization of carbon sources at the post-transcriptional level, also regulates, directly or indirectly, virulence-related processes in P. aeruginosa. Among them, Crc regulates P. aeruginosa cytotoxicity, likely by modulating the activity of the Type III Secretion System (T3SS), which directly injects toxins into eukaryotic host cells. The present work shows that the lack of Crc produces a Type III Secretion-defective phenotype in P. aeruginosa. The observed impairment is a consequence of a reduced expression of the genes encoding the T3SS, together with an impaired secretion of the proteins involved. Our results support that the impaired T3SS activity of the crc defective mutant is, at least partly, a consequence of a defective protein export, probably due to a reduced proton motive force. This work provides new information about the complex regulation of the expression and the activity of the T3SS in P. aeruginosa. Our results highlight the need of a robust bacterial metabolism, which is defective in the ∆crc mutant, to elicit complex and energetically costly virulence strategies, as that provided by the T3SS.


Assuntos
Pseudomonas aeruginosa , Sistemas de Secreção Tipo III , Sistemas de Secreção Tipo III/genética , Sistemas de Secreção Tipo III/metabolismo , Virulência/genética , Pseudomonas aeruginosa/metabolismo , Fatores de Virulência/metabolismo , Fenômenos Fisiológicos Celulares , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica
5.
Int J Mol Sci ; 24(5)2023 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-36902331

RESUMO

Pseudoxanthoma elasticum (PXE) is characterized by low levels of inorganic pyrophosphate (PPi) and a high activity of tissue-nonspecific alkaline phosphatase (TNAP). Lansoprazole is a partial inhibitor of TNAP. The aim was to investigate whether lansoprazole increases plasma PPi levels in subjects with PXE. We conducted a 2 × 2 randomized, double-blind, placebo-controlled crossover trial in patients with PXE. Patients were allocated 30 mg/day of lansoprazole or a placebo in two sequences of 8 weeks. The primary outcome was the differences in plasma PPi levels between the placebo and lansoprazole phases. 29 patients were included in the study. There were eight drop-outs due to the pandemic lockdown after the first visit and one due to gastric intolerance, so twenty patients completed the trial. A generalized linear mixed model was used to evaluate the effect of lansoprazole. Overall, lansoprazole increased plasma PPi levels from 0.34 ± 0.10 µM to 0.41 ± 0.16 µM (p = 0.0302), with no statistically significant changes in TNAP activity. There were no important adverse events. 30 mg/day of lansoprazole was able to significantly increase plasma PPi in patients with PXE; despite this, the study should be replicated with a large number of participants in a multicenter trial, with a clinical end point as the primary outcome.


Assuntos
Pseudoxantoma Elástico , Humanos , Estudos Cross-Over , Difosfatos , Método Duplo-Cego , Diester Fosfórico Hidrolases , Pseudoxantoma Elástico/tratamento farmacológico
6.
Anal Chem ; 94(18): 6760-6770, 2022 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-35467835

RESUMO

The accurate detection of nucleic acids from certain biological pathogens is critical for the diagnosis of human diseases. However, amplified detection of RNA molecules from a complex sample by direct detection of RNA/DNA hybrids remains a challenge. Here, we show that type IIS endonuclease FokI is able to digest DNA duplexes and DNA/RNA hybrids when assisted by a dumbbell-like fluorescent sensing oligonucleotide. As proof of concept, we designed a battery of sensing oligonucleotides against specific regions of the SARS-CoV-2 genome and interrogated the role of FokI relaxation as a potential nicking enzyme for fluorescence signal amplification. FokI-assisted digestion of SARS-CoV-2 probes increases the detection signal of ssDNA and RNA molecules and decreases the limit of detection more than 3.5-fold as compared to conventional molecular beacon approaches. This cleavage reaction is highly specific to its target molecules, and no detection of other highly related B-coronaviruses was observed in the presence of complex RNA mixtures. In addition, the FokI-assisted reaction has a high multiplexing potential, as the combined detection of different viral RNAs, including different SARS-CoV-2 variants, was achieved in the presence of multiple combinations of fluorophores and sensing oligonucleotides. When combined with isothermal rolling circle amplification technologies, FokI-assisted digestion reduced the detection time of SARS-CoV-2 in COVID-19-positive human samples with adequate sensitivity and specificity compared to conventional reverse transcription polymerase chain reaction approaches, highlighting the potential of FokI-assisted signal amplification as a valuable sensing mechanism for the detection of human pathogens.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , DNA , Digestão , Humanos , Técnicas de Amplificação de Ácido Nucleico , Oligonucleotídeos , RNA Viral/genética , SARS-CoV-2/genética , Sensibilidade e Especificidade
7.
Glob Chang Biol ; 28(14): 4439-4458, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35320604

RESUMO

Rear-edge populations at the xeric distribution limit of tree species are particularly vulnerable to forest dieback triggered by drought. This is the case of silver fir (Abies alba) forests located in Southwestern Europe. While silver fir drought-induced dieback patterns have been previously explored, information on the role played by nutritional impairment is lacking despite its potential interactions with tree carbon-water balances. We performed a comparative analysis of radial growth, intrinsic water-use efficiency (iWUE), oxygen isotopes (δ18 O) and nutrient concentrations in leaves of declining (DD) and non-declining (ND) trees in silver fir in four forests in the Spanish Pyrenees. We also evaluated the relationships among dieback predisposition, intraspecific trait variation (wood density and leaf traits) and rhizosphere soil physical-chemical properties. The onset of growth decline in DD trees occurred more than two decades ago, and they subsequently showed low growth resilience against droughts. The DD trees presented consistently lower foliar concentrations of nutrients such as P, K, Cu and Ni than ND trees. The strong effects of foliar nutrient status on growth resilience indices support the key role played by mineral nutrition in tree functioning and growth before, during and after drought. In contrast, variability in wood density and leaf morphological traits, as well as soil properties, showed weak relationships with tree nutritional status and drought performance. At the low elevation, warmer sites, DD trees showed stronger climate-growth relationships and lower δ18 O than ND trees. The uncoupling between iWUE and δ18 O, together with the positive correlations between P and K leaf concentrations and δ18 O, point to deeper soil/bedrock water sources and vertical decoupling between nutrient and water uptake in DD trees. This study provides novel insights into the mechanisms driving silver fir dieback and highlights the need to incorporate tree nutrition into forest dieback studies.


Las poblaciones del límite xérico de distribución de las especies de árboles son particularmente vulnerables al decaimiento forestal inducido por sequía. Este es el caso de los bosques de abeto (Abies alba) situados en el suroeste de Europa. Si bien los patrones de decaimiento provocado por sequía del abeto se han explorado previamente, falta información sobre el papel que desempeña el deterioro nutricional a pesar de sus interacciones potenciales con los balances de agua y carbono de los árboles. En este estudio, hemos realizado un análisis comparativo del crecimiento radial, la eficiencia intrínseca del uso del agua (iWUE), los isótopos de oxígeno (δ18O) y las concentraciones de nutrientes en hojas de árboles decaídos (DD) y no decaídos (ND) en cuatro abetares de los Pirineos españoles. También evaluamos las relaciones entre la predisposición al decaimiento, la variación de rasgos intraespecíficos (densidad de la madera y rasgos de las hojas) y las propiedades físico-químicas de la rizosfera. El inicio de la disminución del crecimiento en los árboles DD ocurrió hace más de dos décadas y posteriormente mostraron una baja resiliencia de crecimiento frente a las sequías. Los árboles DD presentaron concentraciones foliares consistentemente más bajas de nutrientes como P, K, Cu y Ni que los árboles ND. Los fuertes efectos del estado de los nutrientes foliares en los índices de resiliencia del crecimiento respaldan el papel clave que desempeña la nutrición mineral en el funcionamiento y el crecimiento de los árboles antes, durante y después de la sequía. En contraste, la variabilidad en la densidad de la madera y los rasgos morfológicos de las hojas, así como las propiedades del suelo, mostraron una relación débil con el estado nutricional de los árboles y la respuesta del crecimiento a la sequía. En los sitios más cálidos y de baja elevación, los árboles DD mostraron relaciones clima-crecimiento más fuertes y un δ18 O más bajo que los árboles ND. El desacoplamiento entre iWUE y δ18 O, junto con las correlaciones positivas entre las concentraciones foliares de P y K y δ18 O, apuntan a fuentes de agua más profundas del suelo/lecho rocoso y un desacoplamiento vertical entre la absorción de nutrientes y agua en los árboles DD. Este estudio proporciona información novedosa sobre los mecanismos que impulsan el decaimiento del abeto y destaca la necesidad de incorporar la nutrición de los árboles en los estudios de muerte regresiva del bosque.


Assuntos
Carbono , Secas , Florestas , Solo , Árvores , Água
8.
Ecol Appl ; 32(5): e2589, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35333426

RESUMO

Tree-ring data has been widely used to inform about tree growth responses to drought at the individual scale, but less is known about how tree growth sensitivity to drought scales up driving changes in forest dynamics. Here, we related tree-ring growth chronologies and stand-level forest changes in basal area from two independent data sets to test if tree-ring responses to drought match stand forest dynamics (stand basal area growth, ingrowth, and mortality). We assessed if tree growth and changes in forest basal area covary as a function of spatial scale and tree taxa (gymnosperm or angiosperm). To this end, we compared a tree-ring network with stand data from the Spanish National Forest Inventory. We focused on the cumulative impact of drought on tree growth and demography in the period 1981-2005. Drought years were identified by the Standardized Precipitation Evapotranspiration Index, and their impacts on tree growth by quantifying tree-ring width reductions. We hypothesized that forests with greater drought impacts on tree growth will also show reduced stand basal area growth and ingrowth and enhanced mortality. This is expected to occur in forests dominated by gymnosperms on drought-prone regions. Cumulative growth reductions during dry years were higher in forests dominated by gymnosperms and presented a greater magnitude and spatial autocorrelation than for angiosperms. Cumulative drought-induced tree growth reductions and changes in forest basal area were related, but initial stand density and basal area were the main factors driving changes in basal area. In drought-prone gymnosperm forests, we observed that sites with greater growth reductions had lower stand basal area growth and greater mortality. Consequently, stand basal area, forest growth, and ingrowth in regions with large drought impacts was significantly lower than in regions less impacted by drought. Tree growth sensitivity to drought can be used as a predictor of gymnosperm demographic rates in terms of stand basal area growth and ingrowth at regional scales, but further studies may try to disentangle how initial stand density modulates such relationships. Drought-induced growth reductions and their cumulative impacts have strong potential to be used as early-warning indicators of regional forest vulnerability.


Assuntos
Magnoliopsida , Árvores , Mudança Climática , Secas , Florestas
9.
Glob Chang Biol ; 27(9): 1879-1889, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33508887

RESUMO

Climate warming is expected to positively alter upward and poleward treelines which are controlled by low temperature and a short growing season. Despite the importance of treelines as a bioassay of climate change, a global field assessment and posterior forecasting of tree growth at annual scales is lacking. Using annually resolved tree-ring data located across Eurasia and the Americas, we quantified and modeled the relationship between temperature and radial growth at treeline during the 20th century. We then tested whether this temperature-growth association will remain stable during the 21st century using a forward model under two climate scenarios (RCP 4.5 and 8.5). During the 20th century, growth enhancements were common in most sites, and temperature and growth showed positive trends. Interestingly, the relationship between temperature and growth trends was contingent on tree age suggesting biogeographic patterns in treeline growth are contingent on local factors besides climate warming. Simulations forecast temperature-growth decoupling during the 21st century. The growing season at treeline is projected to lengthen and growth rates would increase and become less dependent on temperature rise. These forecasts illustrate how growth may decouple from climate warming in cold regions and near the margins of tree existence. Such projected temperature-growth decoupling could impact ecosystem processes in mountain and polar biomes, with feedbacks on climate warming.


Assuntos
Ecossistema , Árvores , Mudança Climática , Temperatura Baixa , Temperatura
10.
Mol Cell ; 51(3): 283-96, 2013 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-23911927

RESUMO

The ability of cells to respond to changes in nutrient availability is critical for an adequate control of metabolic homeostasis. Mammalian target of rapamycin complex 1 (mTORC1) is a central complex kinase in these processes. The signaling adaptor p62 binds raptor, and integral component of the mTORC1 pathway. p62 interacts with TNF receptor associated factor 6 (TRAF6) and is required for mTORC1 translocation to the lysosome and its subsequent activation. Here we show that TRAF6 is recruited to and activates mTORC1 through p62 in amino acid-stimulated cells. We also show that TRAF6 is necessary for the translocation of mTORC1 to the lysosomes and that the TRAF6-catalyzed K63 ubiquitination of mTOR regulates mTORC1 activation by amino acids. TRAF6, through its interaction with p62 and activation of mTORC1, modulates autophagy and is an important mediator in cancer cell proliferation. Interfering with the p62-TRAF6 interaction serves to modulate autophagy and nutrient sensing.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Choque Térmico/metabolismo , Complexos Multiproteicos/metabolismo , Fator 6 Associado a Receptor de TNF/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Autofagia/fisiologia , Transporte Biológico , Linhagem Celular , Proliferação de Células , Ativação Enzimática , Células HEK293 , Humanos , Lisossomos/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Camundongos Knockout , Mutação , NF-kappa B/metabolismo , Interferência de RNA , RNA Interferente Pequeno , Proteína Sequestossoma-1 , Fator 6 Associado a Receptor de TNF/genética , Ubiquitinação
11.
Childs Nerv Syst ; 37(7): 2223-2232, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33751170

RESUMO

PURPOSE: The aim of this study was to describe our experience in the management of patients with ventriculoperitoneal shunt-related complications (abdominal pseudocyst, bowel-related complications, and ascites) and to propose treatment recommendations. MATERIAL AND METHODS: A retrospective descriptive study was conducted in patients with ventriculoperitoneal shunt-related abdominal complications seen between 2009 and 2019 at a tertiary-care pediatric center. Patients were classified according to their diagnosis into the following: group A (abdominal pseudocyst), group B (bowel-related complications), and group C (ascites). The following variables were studied in all three groups: age, sex, etiology of hydrocephalus, history of pyogenic ventriculitis, history of abdominal surgery, clinical presentation, presence of ventricular enlargement on computed tomography scan, abdominal ultrasonography, shunt series X-ray, cerebrospinal fluid cultures, urgent as well as elective surgical interventions, antibiotic treatment, length of hospital stay, follow-up, and outcome. RESULTS: Overall, 48 patients were analyzed: group A, n=29; group B, n=15; and group C, n=4. In all cases, surgical decision-making was based on symptom severity at the time of diagnosis, presence of ventricular enlargement on computed tomography scan, and cerebrospinal fluid culture results. In patients with positive cultures, the shunt system was removed, and an external ventricular drain was placed. In oligosymptomatic patients, cerebrospinal fluid culture results were awaited to define long-term treatment and in patients with ventricular enlargement or clinically difficult-to-treat symptoms, the distal catheter was exteriorized at the thoracic level. CONCLUSION: In patients with shunt-related abdominal complications, surgical management depends on symptom severity and/or whether infection is present at the time of diagnosis.


Assuntos
Cistos , Hidrocefalia , Abdome/diagnóstico por imagem , Abdome/cirurgia , Criança , Cistos/cirurgia , Humanos , Hidrocefalia/diagnóstico por imagem , Hidrocefalia/etiologia , Hidrocefalia/cirurgia , Estudos Retrospectivos , Derivação Ventriculoperitoneal/efeitos adversos
12.
Glob Chang Biol ; 26(8): 4521-4537, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32388882

RESUMO

Global climate change is expected to further raise the frequency and severity of extreme events, such as droughts. The effects of extreme droughts on trees are difficult to disentangle given the inherent complexity of drought events (frequency, severity, duration, and timing during the growing season). Besides, drought effects might be modulated by trees' phenotypic variability, which is, in turn, affected by long-term local selective pressures and management legacies. Here we investigated the magnitude and the temporal changes of tree-level resilience (i.e., resistance, recovery, and resilience) to extreme droughts. Moreover, we assessed the tree-, site-, and drought-related factors and their interactions driving the tree-level resilience to extreme droughts. We used a tree-ring network of the widely distributed Scots pine (Pinus sylvestris) along a 2,800 km latitudinal gradient from southern Spain to northern Germany. We found that the resilience to extreme drought decreased in mid-elevation and low productivity sites from 1980-1999 to 2000-2011 likely due to more frequent and severe droughts in the later period. Our study showed that the impact of drought on tree-level resilience was not dependent on its latitudinal location, but rather on the type of sites trees were growing at and on their growth performances (i.e., magnitude and variability of growth) during the predrought period. We found significant interactive effects between drought duration and tree growth prior to drought, suggesting that Scots pine trees with higher magnitude and variability of growth in the long term are more vulnerable to long and severe droughts. Moreover, our results indicate that Scots pine trees that experienced more frequent droughts over the long-term were less resistant to extreme droughts. We, therefore, conclude that the physiological resilience to extreme droughts might be constrained by their growth prior to drought, and that more frequent and longer drought periods may overstrain their potential for acclimation.


Assuntos
Secas , Pinus sylvestris , Europa (Continente) , Alemanha , Espanha , Árvores
13.
Proc Natl Acad Sci U S A ; 114(47): E10142-E10150, 2017 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-29109266

RESUMO

Warmer and drier climatic conditions are projected for the 21st century; however, the role played by extreme climatic events on forest vulnerability is still little understood. For example, more severe droughts and heat waves could threaten quaternary relict tree refugia such as Circum-Mediterranean fir forests (CMFF). Using tree-ring data and a process-based model, we characterized the major climate constraints of recent (1950-2010) CMFF growth to project their vulnerability to 21st-century climate. Simulations predict a 30% growth reduction in some fir species with the 2050s business-as-usual emission scenario, whereas growth would increase in moist refugia due to a longer and warmer growing season. Fir populations currently subjected to warm and dry conditions will be the most vulnerable in the late 21st century when climatic conditions will be analogous to the most severe dry/heat spells causing dieback in the late 20th century. Quantification of growth trends based on climate scenarios could allow defining vulnerability thresholds in tree populations. The presented predictions call for conservation strategies to safeguard relict tree populations and anticipate how many refugia could be threatened by 21st-century dry spells.


Assuntos
Abies/fisiologia , Modelos Estatísticos , Dispersão Vegetal/fisiologia , Mudança Climática/estatística & dados numéricos , Simulação por Computador , Secas/estatística & dados numéricos , Previsões , Florestas , Região do Mediterrâneo , Refúgio de Vida Selvagem , Estações do Ano , Árvores
14.
Mol Cell ; 44(1): 134-46, 2011 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-21981924

RESUMO

The signaling adaptor p62 is a critical mediator of important cellular functions, owing to its ability to establish interactions with various signaling intermediaries. Here, we identify raptor as an interacting partner of p62. Thus, p62 is an integral part of the mTORC1 complex and is necessary to mediate amino acid signaling for the activation of S6K1 and 4EBP1. p62 interacts in an amino acid-dependent manner with mTOR and raptor. In addition, p62 binds the Rags proteins and favors formation of the active Rag heterodimer that is further stabilized by raptor. Interestingly, p62 colocalizes with Rags at the lysosomal compartment and is required for the interaction of mTOR with Rag GTPases in vivo and for translocation of the mTORC1 complex to the lysosome, a crucial step for mTOR activation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Choque Térmico/metabolismo , Proteínas/metabolismo , Animais , Autofagia , Proteínas de Transporte/metabolismo , Dimerização , GTP Fosfo-Hidrolases/metabolismo , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Lisossomos/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Complexos Multiproteicos , Células NIH 3T3 , Plasmídeos/metabolismo , Proteína Quinase C/metabolismo , Proteína Regulatória Associada a mTOR , Proteína Sequestossoma-1 , Serina-Treonina Quinases TOR
15.
Proc Natl Acad Sci U S A ; 113(3): 662-7, 2016 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-26729860

RESUMO

Forests play a key role in the carbon balance of terrestrial ecosystems. One of the main uncertainties in global change predictions lies in how the spatiotemporal dynamics of forest productivity will be affected by climate warming. Here we show an increasing influence of climate on the spatial variability of tree growth during the last 120 y, ultimately leading to unprecedented temporal coherence in ring-width records over wide geographical scales (spatial synchrony). Synchrony in growth patterns across cold-constrained (central Siberia) and drought-constrained (Spain) Eurasian conifer forests have peaked in the early 21st century at subcontinental scales (∼ 1,000 km). Such enhanced synchrony is similar to that observed in trees co-occurring within a stand. In boreal forests, the combined effects of recent warming and increasing intensity of climate extremes are enhancing synchrony through an earlier start of wood formation and a stronger impact of year-to-year fluctuations of growing-season temperatures on growth. In Mediterranean forests, the impact of warming on synchrony is related mainly to an advanced onset of growth and the strengthening of drought-induced growth limitations. Spatial patterns of enhanced synchrony represent early warning signals of climate change impacts on forest ecosystems at subcontinental scales.


Assuntos
Mudança Climática , Florestas , Árvores/crescimento & desenvolvimento , Modelos Lineares , Sibéria , Espanha , Especificidade da Espécie , Fatores de Tempo
16.
Glob Chang Biol ; 24(5): 2143-2158, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29488293

RESUMO

Forecasted increase drought frequency and severity may drive worldwide declines in forest productivity. Species-level responses to a drier world are likely to be influenced by their functional traits. Here, we analyse forest resilience to drought using an extensive network of tree-ring width data and satellite imagery. We compiled proxies of forest growth and productivity (TRWi, absolutely dated ring-width indices; NDVI, Normalized Difference Vegetation Index) for 11 tree species and 502 forests in Spain corresponding to Mediterranean, temperate, and continental biomes. Four different components of forest resilience to drought were calculated based on TRWi and NDVI data before, during, and after four major droughts (1986, 1994-1995, 1999, and 2005), and pointed out that TRWi data were more sensitive metrics of forest resilience to drought than NDVI data. Resilience was related to both drought severity and forest composition. Evergreen gymnosperms dominating semi-arid Mediterranean forests showed the lowest resistance to drought, but higher recovery than deciduous angiosperms dominating humid temperate forests. Moreover, semi-arid gymnosperm forests presented a negative temporal trend in the resistance to drought, but this pattern was absent in continental and temperate forests. Although gymnosperms in dry Mediterranean forests showed a faster recovery after drought, their recovery potential could be constrained if droughts become more frequent. Conversely, angiosperms and gymnosperms inhabiting temperate and continental sites might have problems to recover after more intense droughts since they resist drought but are less able to recover afterwards.


Assuntos
Cycadopsida/fisiologia , Secas , Florestas , Magnoliopsida/fisiologia , Região do Mediterrâneo , Espanha , Fatores de Tempo
17.
Cardiol Young ; 28(3): 351-353, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29151383

RESUMO

Inflammatory bowel disease is closely associated with an increased risk for thrombotic events. Thrombosis mostly occurs in the extremities, lungs, and liver; but it can also occur in the ventricles of the heart. The primary goal of this article is to increase awareness of the risk for ventricular thrombosis in this patient population among healthcare professionals and, thus, appropriate prompt use of thromboprophylaxis therapy for these patients during acute flare-ups. Early diagnosis and intervention are critical for ventricular thrombosis to prevent systemic embolisation of the thrombus. Concisely, inflammatory bowel disease predisposes to the development of thrombi. A low threshold for the use of imaging studies to detect such thrombi is warranted.


Assuntos
Cardiopatias/complicações , Doenças Inflamatórias Intestinais/complicações , Trombose/complicações , Técnicas de Imagem Cardíaca , Diagnóstico Precoce , Cardiopatias/diagnóstico por imagem , Ventrículos do Coração/diagnóstico por imagem , Humanos , Trombose/diagnóstico por imagem
18.
J BUON ; 23(4): 910-918, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30358193

RESUMO

PURPOSE: With advancements in radiation oncology techniques, the use of radiation therapy (RT) as a treatment modality for cancer has been steadily increasing. Incidental radiation exposure to surrounding tissue during breast cancer treatment has been known to cause myocardial damage, the extent of which can be detected with single-photon emission computed tomography (SPECT) perfusion studies. We undertook a systematic review and meta-analysis to investigate the impact of RT on myocardial perfusion. METHODS: A systematic review of the literature was conducted to identify 17 studies, of which 4 were included in this meta-analysis and 13 were included in the narrative synthesis. RESULTS: The incidence of post-radiation cardiac perfusion defects on SPECT was significantly higher in patients who received RT for left-sided breast cancer compared to those who had RT for right-sided breast cancer (OR=3.10, 95% CI 1.35-7.08, p=0.007). CONCLUSION: In patients who undergo RT for left-sided breast cancer, the incidence of post-radiation cardiac perfusion defects on SPECT is higher compared to patients who undergo RT for right-sided breast cancer.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/radioterapia , Coração/diagnóstico por imagem , Lesões por Radiação/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Neoplasias da Mama/patologia , Feminino , Coração/efeitos da radiação , Humanos , Miocárdio/patologia , Lesões por Radiação/patologia
19.
Glob Chang Biol ; 23(10): 4106-4116, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28100041

RESUMO

Ongoing changes in global climate are altering ecological conditions for many species. The consequences of such changes are typically most evident at the edge of a species' geographical distribution, where differences in growth or population dynamics may result in range expansions or contractions. Understanding population responses to different climatic drivers along wide latitudinal and altitudinal gradients is necessary in order to gain a better understanding of plant responses to ongoing increases in global temperature and drought severity. We selected Scots pine (Pinus sylvestris L.) as a model species to explore growth responses to climatic variability (seasonal temperature and precipitation) over the last century through dendrochronological methods. We developed linear models based on age, climate and previous growth to forecast growth trends up to year 2100 using climatic predictions. Populations were located at the treeline across a latitudinal gradient covering the northern, central and southernmost populations and across an altitudinal gradient at the southern edge of the distribution (treeline, medium and lower elevations). Radial growth was maximal at medium altitude and treeline of the southernmost populations. Temperature was the main factor controlling growth variability along the gradients, although the timing and strength of climatic variables affecting growth shifted with latitude and altitude. Predictive models forecast a general increase in Scots pine growth at treeline across the latitudinal distribution, with southern populations increasing growth up to year 2050, when it stabilizes. The highest responsiveness appeared at central latitude, and moderate growth increase is projected at the northern limit. Contrastingly, the model forecasted growth declines at lowland-southern populations, suggesting an upslope range displacement over the coming decades. Our results give insight into the geographical responses of tree species to climate change and demonstrate the importance of incorporating biogeographical variability into predictive models for an accurate prediction of species dynamics as climate changes.


Assuntos
Mudança Climática , Pinus sylvestris/crescimento & desenvolvimento , Clima , Florestas , Geografia , Temperatura , Árvores
20.
Glob Chang Biol ; 23(7): 2705-2719, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-27782362

RESUMO

Growth models can be used to assess forest vulnerability to climate warming. If global warming amplifies water deficit in drought-prone areas, tree populations located at the driest and southernmost distribution limits (rear-edges) should be particularly threatened. Here, we address these statements by analyzing and projecting growth responses to climate of three major tree species (silver fir, Abies alba; Scots pine, Pinus sylvestris; and mountain pine, Pinus uncinata) in mountainous areas of NE Spain. This region is subjected to Mediterranean continental conditions, it encompasses wide climatic, topographic and environmental gradients, and, more importantly, it includes rear-edges of the continuous distributions of these tree species. We used tree-ring width data from a network of 110 forests in combination with the process-based Vaganov-Shashkin-Lite growth model and climate-growth analyses to forecast changes in tree growth during the 21st century. Climatic projections were based on four ensembles CO2 emission scenarios. Warm and dry conditions during the growing season constrain silver fir and Scots pine growth, particularly at the species rear-edge. By contrast, growth of high-elevation mountain pine forests is enhanced by climate warming. The emission scenario (RCP 8.5) corresponding to the most pronounced warming (+1.4 to 4.8 °C) forecasted mean growth reductions of -10.7% and -16.4% in silver fir and Scots pine, respectively, after 2050. This indicates that rising temperatures could amplify drought stress and thus constrain the growth of silver fir and Scots pine rear-edge populations growing at xeric sites. Contrastingly, mountain pine growth is expected to increase by +12.5% due to a longer and warmer growing season. The projections of growth reduction in silver fir and Scots pine portend dieback and a contraction of their species distribution areas through potential local extinctions of the most vulnerable driest rear-edge stands. Our modeling approach provides accessible tools to evaluate forest vulnerability to warmer conditions.


Assuntos
Mudança Climática , Florestas , Árvores/crescimento & desenvolvimento , Clima , Secas , Modelos Teóricos , Espanha
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