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1.
Front Neurol ; 15: 1369443, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38638309

RESUMO

Background: Long-term follow-up of cerebral aneurysms treated with the Silk Vista Baby (SVB) flow diverter is lacking. This study aimed to assess the technical success, procedural safety, and efficacy of the SVB (Balt, Montmorency, France) for the treatment of intracranial aneurysms in small cerebral vessels over a mid-to long-term follow-up. Methods: We retrospectively analyzed a prospectively maintained database of patients treated with the SVB between September 2018 and June 2021. Data regarding patient demographics, aneurysm characteristics, and technical procedures were also collected. Angiographic and clinical findings were recorded during the procedure and over a period of at least 12 months. Results: Angiographic and clinical follow-up data were available for 50 patients/50 aneurysms. The procedural complication rate was 8%. At 12 months, the final results showed a technical success rate of 100%, the re rupture rate was 0%, neuromorbidity and mortality rates of 4 and 0%, respectively, and an almost complete occlusion rate of 94%. Conclusion: Treatment of complex intracranial aneurysms with the SVB was safe and effective. Long-term results showed high rates of adequate and stable occlusions.

2.
ESC Heart Fail ; 11(2): 1194-1204, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38287508

RESUMO

AIMS: Frailty and dependence are frequent in patients admitted for acute heart failure (AHF), but their prognostic significance is unknown, especially in young adults. We aimed to study in adults admitted for AHF, regardless of age, the effect of frailty and dependence on the incidence of mortality and a combined event of mortality, readmissions for AHF, and visits to the emergency room (ER) for AHF at 1 and 6 months. METHODS AND RESULTS: We designed a prospective cohort study by including all the patients with AHF admitted in our Cardiology Department from July 2020 through May 2021. A multidimensional geriatric assessment was performed during the admission. We clinically followed up the patients 6 months after discharge. We enrolled 202 patients. The mean age was 73 ± 12.32 years, and 100 (49.5%) of the patients were elderly (>75 years). Just 78 patients (38.6%) were women, and 100 (49.5%) had previous HF. Frailty (FRAIL ≥ 3) was observed in 68 (33.7%) patients (mean FRAIL score: 1.88 ± 1.48). Dependence (Barthel < 100) was observed in 65 (32.2%) patients (mean Barthel index: 94.38 ± 11.21). Frailty and dependence showed a significant association with both prognostic events at 1 and 6 months. In the multivariable analysis, frailty was associated with higher mortality at 1 month [hazard ratio (HR) 12.61, 95% confidence interval (CI) 1.57-101.47, P = 0.017] but not at 6 months (HR 2.25, 95% CI 0.61-8.26, P = 0.224) or with the combined endpoint at neither 1 month (HR 1.64, 95% CI 0.54-5.03, P = 0.384) nor 6 months (HR 1.35, 95% CI 0.75-2.46, P = 0.320). Dependence was related to higher mortality at 1 month (HR 13.04, 95% CI 1.62-104.75, P = 0.016) and 6 months (HR 7.18, 95% CI 1.99-25.86, P = 0.003) and to higher incidence of the combined event at 1 month (HR 5.93, 95% CI 1.63-21.50, P = 0.007) and 6 months (HR 2.62, 95% CI 1.49-4.61, P = 0.001). CONCLUSIONS: In AHF patients, frailty and dependence implied a worse prognosis, rising mortality, readmissions, and ER visits for AHF.


Assuntos
Fragilidade , Insuficiência Cardíaca , Humanos , Feminino , Idoso , Pessoa de Meia-Idade , Idoso de 80 Anos ou mais , Lactente , Masculino , Prognóstico , Estudos Prospectivos , Avaliação Geriátrica
3.
Mar Environ Res ; 188: 106006, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37182324

RESUMO

Global change is imposing significant losses in the functional traits of marine organisms. Although areas of climatic refugia ameliorate local conditions and help them to persist, the extent to which mesoscale effects contribute for intraregional variability on population traits and conservation is uncertain. Here we assess patterns of conservation status of Fucus guiryi, the main intertidal habitat-forming seaweed in the Strait of Gibraltar (southern Spain and northern Morocco). We investigated the demography, reproductive phenology, and morphology at northern and southern side populations. Population traits were compared seasonally within populations from each side, and at spatial scale in early summer 2019. In the last decade three populations became extinct; two marginal populations had dispersed individuals with a narrower fertility season and miniaturized individuals below 3 cm; and five populations showed variable density and cover with more than 20% of reproductive individuals over the seasons. Highest density, cover, morphology, and reproductive potential was detected at one population from each side, suggesting local-scale climatic refugia in upwelling areas located inside marine protected areas. Southern recruits were more warm-tolerant but grew less at colder conditions than northern ones, revealing a mesoscale heterogeneity in thermal affinities. This study evidenced functional losses and distinct reproductive strategies experienced by F. guiryi at peripheral locations and urges to prioritize its conservation and restoration at contemporary climatic refugia.


Assuntos
Refúgio de Vida Selvagem , Alga Marinha , Humanos , Espanha , Ecossistema , Gibraltar , Mudança Climática
4.
Heart Lung ; 60: 133-138, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36996756

RESUMO

BACKGROUND: Heart failure prevalence is increasing in elder adults. These patients usually present geriatric syndromes, especially frailty. The effect of frailty on heart failure is under discussion but there are few data about the clinical characterization of frail patients who are admitted for acute heart failure decompensation. OBJECTIVE: The purpose of this study was to study the differences in clinical baseline variables and geriatric scales between frail and non-frail patients admitted to the Cardiology unit via the Emergency Department for acute heart failure. METHODS: We enrolled all patients with acute heart failure who were admitted to the Cardiology unit from the Emergency Department of our hospital from July 2020 through May 2021. A multidimensional and comprehensive geriatric assessment was performed at the moment of admission. We studied differences in baseline variables and geriatric scales according to the frailty status determined by the FRAIL scale. RESULTS: A total of 202 patients were included. In the whole population, 68 (33.7%) patients presented frailty defined by a FRAIL score ≥ 3. The frail patients were older (80±9 vs. 69±12 years; p<0.001), and had a worse quality of life (58.31±12.18 vs.39.26±13.71 points; p<0.001) according to the Minnesota scale, presented high comorbidity (47 (69.1%) vs. 67 (50.4%) patients; p = 0.011) defined as ≥3 points according to the Charlson scale and were more dependent (40 (58.8%) vs. 25 (18.8%) patients; p<0.001) according to the Barthel scale. The frail patients presented higher MAGGIC risk scores (24.09±4.99 vs. 18.89±6.26; p<0.001). Despite this adverse profile, the treatments prescribed during the admission and at the hospital discharge were similar. CONCLUSIONS: The prevalence of geriatric syndromes, especially frailty, is very high in patients admitted for acute heart failure. Frail patients with acute heart failure had an adverse clinical profile with more prevalence of concomitant geriatric syndromes. Therefore, we consider that a geriatric assessment should be performed during the admission of acute heart failure patients to improve care and attention.


Assuntos
Cardiologia , Fragilidade , Insuficiência Cardíaca , Humanos , Idoso , Fragilidade/epidemiologia , Fragilidade/complicações , Idoso Fragilizado , Qualidade de Vida , Avaliação Geriátrica/métodos , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/epidemiologia
6.
Biomolecules ; 12(2)2022 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-35204746

RESUMO

Frailty has traditionally been studied in the elderly population but scarcely in younger individuals. The objective of the present study is to analyze differences according to age in the diagnostic performance of cardiac biomarkers to predict frailty in patients admitted to the hospital for acute heart failure (AHF). A frailty assessment was performed with the SPPB and FRAIL scales (score > 3). We included 201 patients who were divided according to age: those older and younger than 75 years. In the younger group, no biomarker was related to the presence of frailty. This was mainly determined by age and comorbidities. In the elderly group, NT-proBNP was significantly related to the presence of frailty, but none of the baseline characteristics were. The best cut-off point in the elderly group for NT-proBNP was 4000 pg/mL. The area under the curve (AUC) for proBNP for frailty detection was 0.62 in the elderly. Another similar frailty scale, the SPPB, also showed a similar AUC in this group; however, adding the NT-proBNP (one point if NT-proBNP < 4000 pg/mL), it showed a slightly higher yield (AUC 0.65). The addition of biomarkers could improve frailty detection in members of the elderly population who are admitted to the hospital for AHF.


Assuntos
Fragilidade , Insuficiência Cardíaca , Idoso , Área Sob a Curva , Biomarcadores , Fragilidade/diagnóstico , Insuficiência Cardíaca/diagnóstico , Humanos , Fragmentos de Peptídeos
7.
Ecol Evol ; 10(11): 5045-5055, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32551080

RESUMO

The overall mean levels of different environmental variables are changing rapidly in the present Anthropocene, in some cases creating lethal conditions for organisms. Under this new scenario, it is crucial to know whether the adaptive potential of organisms allows their survival under different rates of environmental change. Here, we used an eco-evolutionary approach, based on a ratchet protocol, to investigate the effect of environmental change rate on the limit of resistance to salinity of three strains of the toxic cyanobacterium Microcystis aeruginosa. Specifically, we performed two ratchet experiments in order to simulate two scenarios of environmental change. In the first scenario, the salinity increase rate was slow (1.5-fold increase), while in the second scenario, the rate was faster (threefold increase). Salinity concentrations ranging 7-10 gL-1 NaCl (depending on the strain) inhibited growth completely. However, when performing the ratchet experiment, an increase in salinity resistance (9.1-13.6 gL-1 NaCl) was observed in certain populations. The results showed that the limit of resistance to salinity that M. aeruginosa strains were able to reach depended on the strain and on the rate of environmental change. In particular, a higher number of populations were able to grow under their initial lethal salinity levels when the rate of salinity increment was slow. In future scenarios of increased salinity in natural freshwater bodies, this could have toxicological implications due to the production of microcystin by this species.

8.
Rev. esp. cardiol. (Ed. impr.) ; 72(2): 130-137, feb. 2019. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-182544

RESUMO

Introducción y objetivos: El hospital de día del área del corazón (HDC) es una alternativa asistencial a la hospitalización convencional relacionada con procedimientos cardiológicos programados. Los objetivos de este estudio son analizar la actividad asistencial, la calidad de la asistencia y el coste-efectividad del HDC. Métodos: Estudio observacional descriptivo de la actividad asistencial durante el primer año de funcionamiento del HDC. La calidad asistencial se analizó mediante el índice de sustitución (ambulatorización de los procedimientos programados), la tasa de cancelación, complicaciones y una encuesta de satisfacción. Para el coste-efectividad, se calculó el ahorro económico relacionado con las estancias hospitalarias evitadas. Resultados: Se atendió a un total de 1.646 pacientes (media de edad, 69 ± 15 años; el 60% varones). Se programaron 2.550 procedimientos con una tasa de cancelación del 4%; la cardioversión eléctrica fue el procedimiento con más suspensiones. La ambulatorización de los procedimientos invasivos programados fue del 66%. Únicamente fue necesario reingresar a 1 paciente por insuficiencia cardiaca. La mayoría de los pacientes encuestados consideraron buena o muy buena la atención recibida en el HDC (95%). La ambulatorización parcial de los procedimientos invasivos supuso un ahorro económico en estancias hospitalarias de 219.199,55 euros, superior a los costes del primer año de funcionamiento del HDC. Conclusiones: El HDC del centro ha permitido la ambulatorización de más de 2 tercios de los procedimientos invasivos manteniendo la calidad de la asistencia. En el primer año de funcionamiento se ha amortizado el gasto derivado de su puesta en marcha, gracias a una importante reducción de los ingresos hospitalarios


Introduction and objectives: The cardiology day hospital (CDH) is an alternative to hospitalization for scheduled cardiological procedures. The aims of this study were to analyze the activity, quality of care and the cost-effectiveness of a CDH. Methods: An observational descriptive study was conducted of the health care activity during the first year of operation of DHHA. The quality of care was analyzed through the substitution rate (outpatient procedures), cancellation rates, complications, and a satisfaction survey. For cost-effectiveness, we calculated the economic savings of avoided hospital stays. Results: A total of 1646 patients were attended (mean age 69 ± 15 years, 60% men); 2550 procedures were scheduled with a cancellation rate of 4%. The most frequently cancelled procedure was electrical cardioversion. The substitution rate for scheduled invasive procedures was 66%. Only 1 patient required readmission after discharge from the CDH due to heart failure. Most surveyed patients (95%) considered the care received in the CDH to be good or very good. The saving due to outpatient-converted procedures made possible by the CDH was € 219 199.55, higher than the cost of the first year of operation. Conclusions: In our center, the CDH allowed more than two thirds of the invasive procedures to be performed on an outpatient basis, while maintaining the quality of care. In the first year of operation, the expenses due to its implementation were offset by a significant reduction in hospital admissions


Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Institutos de Cardiologia/organização & administração , Hospital Dia/organização & administração , Análise Custo-Benefício , Instituições de Assistência Ambulatorial/organização & administração , Procedimentos Cirúrgicos Ambulatórios/estatística & dados numéricos , Avaliação de Processos e Resultados em Cuidados de Saúde/estatística & dados numéricos
9.
Rev Esp Cardiol (Engl Ed) ; 72(2): 130-137, 2019 Feb.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-29793830

RESUMO

INTRODUCTION AND OBJECTIVES: The cardiology day hospital (CDH) is an alternative to hospitalization for scheduled cardiological procedures. The aims of this study were to analyze the activity, quality of care and the cost-effectiveness of a CDH. METHODS: An observational descriptive study was conducted of the health care activity during the first year of operation of DHHA. The quality of care was analyzed through the substitution rate (outpatient procedures), cancellation rates, complications, and a satisfaction survey. For cost-effectiveness, we calculated the economic savings of avoided hospital stays. RESULTS: A total of 1646 patients were attended (mean age 69 ± 15 years, 60% men); 2550 procedures were scheduled with a cancellation rate of 4%. The most frequently cancelled procedure was electrical cardioversion. The substitution rate for scheduled invasive procedures was 66%. Only 1 patient required readmission after discharge from the CDH due to heart failure. Most surveyed patients (95%) considered the care received in the CDH to be good or very good. The saving due to outpatient-converted procedures made possible by the CDH was € 219 199.55, higher than the cost of the first year of operation. CONCLUSIONS: In our center, the CDH allowed more than two thirds of the invasive procedures to be performed on an outpatient basis, while maintaining the quality of care. In the first year of operation, the expenses due to its implementation were offset by a significant reduction in hospital admissions.


Assuntos
Hospital Dia/normas , Qualidade da Assistência à Saúde , Idoso , Procedimentos Cirúrgicos Ambulatórios/economia , Procedimentos Cirúrgicos Ambulatórios/normas , Unidades de Cuidados Coronarianos/economia , Unidades de Cuidados Coronarianos/normas , Análise Custo-Benefício , Hospital Dia/economia , Atenção à Saúde/economia , Atenção à Saúde/normas , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Satisfação do Paciente , Complicações Pós-Operatórias/economia , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Espanha , Procedimentos Cirúrgicos Torácicos/economia , Procedimentos Cirúrgicos Torácicos/normas , Procedimentos Cirúrgicos Torácicos/estatística & dados numéricos
10.
Int J Mol Sci ; 19(6)2018 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-29795043

RESUMO

Posidonia oceanica (L.) Delile is a seagrass, the only group of vascular plants to colonize the marine environment. Seawater is an extreme yet stable environment characterized by high salinity, alkaline pH and low availability of essential nutrients, such as nitrate and phosphate. Classical depletion experiments, membrane potential and cytosolic sodium measurements were used to characterize the high-affinity NO3-, Pi and amino acids uptake mechanisms in this species. Net uptake rates of both NO3- and Pi were reduced by more than 70% in the absence of Na⁺. Micromolar concentrations of NO3- depolarized mesophyll leaf cells plasma membrane. Depolarizations showed saturation kinetics (Km = 8.7 ± 1 µM NO3-), which were not observed in the absence of Na⁺. NO3- induced depolarizations at increasing Na⁺ also showed saturation kinetics (Km = 7.2 ± 2 mM Na⁺). Cytosolic Na⁺ measured in P. oceanica leaf cells (17 ± 2 mM Na⁺) increased by 0.4 ± 0.2 mM Na⁺ upon the addition of 100 µM NO3-. Na⁺-dependence was also observed for high-affinity l-ala and l-cys uptake and high-affinity Pi transport. All together, these results strongly suggest that NO3-, amino acids and Pi uptake in P. oceanica leaf cells are mediated by high-affinity Na⁺-dependent transport systems. This mechanism seems to be a key step in the process of adaptation of seagrasses to the marine environment.


Assuntos
Alismatales/metabolismo , Aminoácidos/metabolismo , Membrana Celular/metabolismo , Nitratos/metabolismo , Fosfatos/metabolismo , Sódio/metabolismo , Transporte Biológico , Membrana Celular/fisiologia , Citoplasma/metabolismo , Potenciais da Membrana , Proteínas de Membrana Transportadoras/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo
11.
Photosynth Res ; 127(3): 295-305, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26275764

RESUMO

Mechanisms of inorganic carbon assimilation were investigated in the four deep-water kelps inhabiting sea bottoms at the Strait of Gibraltar; these species are distributed at different depths (Saccorhiza polysiches at shallower waters, followed by Laminaria ochroleuca, then Phyllariopsis brevipes and, at the deepest bottoms, Phyllariopsis purpurascens). To elucidate the capacity to use HCO3(-) as a source of inorganic carbon for photosynthesis in the kelps, different experimental approaches were used. Specifically, we measured the irradiance-saturated gross photosynthetic rate versus pH at a constant dissolved inorganic carbon (DIC) concentration of 2 mM, the irradiance-saturated apparent photosynthesis (APS) rate versus DIC, the total and the extracellular carbonic anhydrase (CAext), the observed and the theoretical photosynthetic rates supported by the spontaneous dehydration of HCO3(-) to CO2, and the δ(13)C signature in tissues of the algae. While S. polyschides and L. ochroleuca showed photosynthetic activity at pH 9.5 (around 1.0 µmol O2 m(-2) s(-1)), the activity was close to zero in both species of Phyllariopsis. The APS versus DIC was almost saturated for the DIC values of natural seawater (2 mM) in S. polyschides and L. ochroleuca, but the relationship was linear in P. brevipes and P. purpurascens. The four species showed total and CAext activities but the inhibition of the CAext originated the observed photosynthetic rates at pH 8.0 to be similar to the theoretical rates that could be supported by the spontaneous dehydration of HCO3(-). The isotopic (13)C signatures ranged from -17.40 ± 1.81 to -21.11 ± 1.73 ‰ in the four species. Additionally, the δ(13)C signature was also measured in the deep-water Laminaria rodriguezii growing at 60-80 m, showing even a more negative value of -26.49 ± 1.25 ‰. All these results suggest that the four kelps can use HCO3(-) as external carbon source for photosynthesis mainly by the action of external CAext, but they also suggest that the species inhabiting shallower waters show a higher capacity than the smaller kelps living in deeper waters. In fact, the photosynthesis in the two Phyllariopsis species could be accomplished by the spontaneous dehydration of HCO3(-) to CO2. These differences in the capacity to use HCO3(-) in photosynthesis among species could be important considering the increasing levels of atmospheric CO2 predicted for the near future.


Assuntos
Carbono/metabolismo , Compostos Inorgânicos/metabolismo , Kelp/metabolismo , Fotossíntese , Água do Mar/química , Anidrases Carbônicas/metabolismo , Gibraltar , Concentração de Íons de Hidrogênio , Kelp/efeitos da radiação , Luz , Oxigênio/metabolismo , Fotossíntese/efeitos da radiação
12.
Microb Ecol ; 71(4): 860-72, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26677166

RESUMO

The cyanobacterium Microcystis aeruginosa is a mesophilic freshwater organism, which cannot tolerate sulphide. However, it was possible to isolate a sulphide-resistant (S(r)) mutant strain that was able to survive in a normally lethal medium sulphide. In order to evaluate the cost of the mutation conferring sulphide resistance in the S(r) strain of M. aeruginosa, the morphology and the photosynthetic performance were compared to that found in the wild-type, sulphide-sensitive (S(s)) strain. An increase in size and a disrupted morphology was observed in S(r) cells in comparison to the S(s) counterpart. Phycoerythrin and phycocyanin levels were higher in the S(r) than in the S(s) cells, whereas a higher carotenoid content, per unit volume, was found in the S(s) strain. The irradiance-saturated photosynthetic oxygen-production rate (GPR max) and the photosynthetic efficiency (measured both by oxygen production and fluorescence, α(GPR) and α(ETR)) were lower in the S(r) strain than in the wild-type. These results appear to be the result of package effect. On the other hand, the S(r) strain showed higher quantum yield of non-photochemical quenching, especially those regulated mechanisms (estimated throughout qN and Y(NPQ)) and a significantly lower slope in the maximum quantum yield of light-adapted samples (Fv'/Fm') compared to the S(s) strain. These findings point to a change in the regulation of the quenching of the transition states (qT) in the S(r) strain which may be generated by a change in the distribution of thylakoidal membranes, which somehow could protect metalloenzymes of the electron transport chain from the lethal effect of sulphide.


Assuntos
Microcystis/efeitos dos fármacos , Microcystis/metabolismo , Mutação , Sulfetos/farmacologia , Carotenoides/análise , Carotenoides/metabolismo , Clorofila/metabolismo , Água Doce/microbiologia , Microcystis/genética , Microcystis/ultraestrutura , Microscopia Eletrônica de Transmissão , Oxigênio/metabolismo , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Ficocianina/análise , Ficoeritrina/análise , Espanha
13.
Microb Ecol ; 66(4): 742-51, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23880793

RESUMO

Los Baños de Vilo (S Spain) is a natural spa characterized by extreme sulphureous waters; however, populations of chlorophyceans inhabit in the spa. The adaptation mechanisms allowing resistance by photosynthetic microorganisms to the extreme sulphureous waters were studied by using a modified Luria-Delbrück fluctuation analysis. For this purpose, the adaptation of the chlorophycean Dictyosphaerium chlorelloides and the cyanobacterium Microcystis aeruginosa (both isolated from non-sulphureous water) were analysed in order to distinguish between physiological adaptation (acclimation) and genetic adaptation by the selection of rare spontaneous mutations. Acclimation to the extreme water was achieved by D. chlorelloides; however, M. aeruginosa cells proliferated as a consequence of selection of favoured mutants (i.e. genetic adaptation). The resistant cells of M. aeruginosa appeared with a frequency of 7.1 × 10(-7) per cell per generation, and the frequency of the resistant allele, under non-selective conditions, was estimated to be 1.1 × 10(-6) per cells as a consequence of the balance mutation-selection. It could be hypothesized that the populations of eukaryotic algae living in the Los Baños de Vilo could be the descendants of chlorophyceans that arrived fortuitously at the spa in the past. On the other hand, cyanobacteria could quickly adapt by the selection of favoured mutants. The single mutation that allows resistance to sulphureous water from Baños de Vilo in M. aeruginosa represents a phenotypic burden impairing growth rate and photosynthetic performance. The resistant-variant cells of M. aeruginosa showed a lower acclimated growth rate and a decreased maximum quantum yield and photosynthetic efficiency, in comparison to the wild-type cells.


Assuntos
Clorófitas/fisiologia , Microcystis/metabolismo , Fotossíntese , Sulfetos/metabolismo , Adaptação Fisiológica , Clorófitas/genética , Microcystis/genética , Mutação , Seleção Genética , Espanha , Sulfetos/análise , Água/análise
14.
Plant Cell Environ ; 36(12): 2135-49, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23550888

RESUMO

The endosomal LeNHX2 ion transporter exchanges H(+) with K(+) and, to lesser extent, Na(+) . Here, we investigated the response to NaCl supply and K(+) deprivation in transgenic tomato (Solanum lycopersicum L.) overexpressing LeNHX2 and show that transformed tomato plants grew better in saline conditions than untransformed controls, whereas in the absence of K(+) the opposite was found. Analysis of mineral composition showed a higher K(+) content in roots, shoots and xylem sap of transgenic plants and no differences in Na(+) content between transgenic and untransformed plants grown either in the presence or the absence of 120 mm NaCl. Transgenic plants showed higher Na(+)/H(+) and, above all, K(+)/H(+) transport activity in root intracellular membrane vesicles. Under K(+) limiting conditions, transgenic plants enhanced root expression of the high-affinity K(+) uptake system HAK5 compared to untransformed controls. Furthermore, tomato overexpressing LeNHX2 showed twofold higher K(+) depletion rates and half cytosolic K(+) activity than untransformed controls. Under NaCl stress, transgenic plants showed higher uptake velocity for K(+) and lower cytosolic K(+) activity than untransformed plants. These results indicate the fundamental role of K(+) homeostasis in the better performance of LeNHX2 overexpressing tomato under NaCl stress.


Assuntos
Antiporters/metabolismo , Proteínas de Plantas/metabolismo , Potássio/metabolismo , Tolerância ao Sal , Solanum lycopersicum/fisiologia , Antiporters/genética , Citosol/efeitos dos fármacos , Citosol/metabolismo , Endossomos/efeitos dos fármacos , Endossomos/metabolismo , Fluorescência , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Homeostase/genética , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/metabolismo , Cinética , Solanum lycopersicum/efeitos dos fármacos , Solanum lycopersicum/genética , Solanum lycopersicum/crescimento & desenvolvimento , Potenciais da Membrana/efeitos dos fármacos , Fenótipo , Proteínas de Plantas/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Transporte Proteico/efeitos dos fármacos , Prótons , Tolerância ao Sal/efeitos dos fármacos , Tolerância ao Sal/genética , Sódio/metabolismo , Cloreto de Sódio/farmacologia , Fatores de Tempo
15.
Ecol Evol ; 2(6): 1251-9, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22833798

RESUMO

The roles of adaptation, chance, and history on evolution of the toxic dinoflagellate Alexandrium minutum Halim, under selective conditions simulating global change, have been addressed. Two toxic strains (AL1V and AL2V), previously acclimated for two years at pH 8.0 and 20°C, were transferred to selective conditions: pH 7.5 to simulate acidification and 25°C. Cultures under selective conditions were propagated until growth rate and toxin cell quota achieved an invariant mean value at 720 days (ca. 250 and ca. 180 generations for strains AL1V and AL2V, respectively). Historical contingencies strongly constrained the evolution of growth rate and toxin cell quota, but the forces involved in the evolution were not the same for both traits. Growth rate was 1.5-1.6 times higher than the one measured in ancestral conditions. Genetic adaptation explained two-thirds of total adaptation while one-third was a consequence of physiological adaptation. On the other hand, the evolution of toxin cell quota showed a pattern attributable to neutral mutations because the final variances were significantly higher than those measured at the start of the experiment. It has been hypothesized that harmful algal blooms will increase under the future scenario of global change. Although this study might be considered an oversimplification of the reality, it can be hypothesized that toxic blooms will increase but no predictions can be advanced about toxicity.

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