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1.
J Food Sci Technol ; 60(6): 1749-1760, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37179799

RESUMO

In vitro and in vivo studies have reported the potential cardioprotective effects of fermented milks (FM). The aim of the present study was to evaluate the inhibitory activities of angiotensin converting enzyme (ACE), thrombin enzyme (TI) and micellar solubility of cholesterol of FM after 24 and 48 h of fermentation with Limosilactobacillus fermentum (J20, J23, J28 and J38), Lactiplantibacillus plantarum (J25) or Lactiplantibacillus pentosus (J34 and J37) exposed to simulated gastrointestinal digestion. Results showed that FM with J20 and J23 at 48 h of fermentation presented significantly (p < 0.05) higher degree of hydrolysis than other FM, and were not significantly different (p > 0.05) between them. Conversely, peptide relative abundance was significantly (p < 0.05) higher in FM with J20 than FM with J23. Moreover, IC50 (protein concentration necessary to inhibit enzyme activity by 50%) for ACE inhibition were 0.33 and 0.5 mg/mL for FM with J20 and J23, respectively. For TI inhibition, the IC50 were 0.3 and 0.24 mg/mL for FM with J20 and J23, respectively. Results exhibited 51 and 74% inhibition of micellar solubility cholesterol for FM with J20 and J23, respectively. Therefore, these results showed that not only peptide abundance, but also specific peptides might be responsible for these potential cardioprotective effects.

2.
Front Plant Sci ; 13: 1058774, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36704154

RESUMO

Chloride (Cl-) and nitrate ( NO 3 - ) are closely related anions involved in plant growth. Their similar physical and chemical properties make them to interact in cellular processes like electrical balance and osmoregulation. Since both anions share transport mechanisms, Cl- has been considered to antagonize NO 3 - uptake and accumulation in plants. However, we have recently demonstrated that Cl- provided at beneficial macronutrient levels improves nitrogen (N) use efficiency (NUE). Biochemical mechanisms by which beneficial Cl- nutrition improves NUE in plants are poorly understood. First, we determined that Cl- nutrition at beneficial macronutrient levels did not impair the NO 3 - uptake efficiency, maintaining similar NO 3 - content in the root and in the xylem sap. Second, leaf NO 3 - content was significantly reduced by the treatment of 6 mM Cl- in parallel with an increase in NO 3 - utilization and NUE. To verify whether Cl- nutrition reduces leaf NO 3 - accumulation by inducing its assimilation, we analysed the content of N forms and the activity of different enzymes and genes involved in N metabolism. Chloride supply increased transcript accumulation and activity of most enzymes involved in NO 3 - assimilation into amino acids, along with a greater accumulation of organic N (mostly proteins). A reduced glycine/serine ratio and a greater ammonium accumulation pointed to a higher activity of the photorespiration pathway in leaves of Cl--treated plants. Chloride, in turn, promoted higher transcript levels of genes encoding enzymes of the photorespiration pathway. Accordingly, microscopy observations suggested strong interactions between different cellular organelles involved in photorespiration. Therefore, in this work we demonstrate for the first time that the greater NO 3 - utilization and NUE induced by beneficial Cl- nutrition is mainly due to the stimulation of NO 3 - assimilation and photorespiration, possibly favouring the production of ammonia, reductants and intermediates that optimize C-N re-utilization and plant growth. This work demonstrates new Cl- functions and remarks on its relevance as a potential tool to manipulate NUE in plants.

3.
J Exp Bot ; 72(14): 5246-5261, 2021 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-33783493

RESUMO

Chloride (Cl-), traditionally considered harmful for agriculture, has recently been defined as a beneficial macronutrient with specific roles that result in more efficient use of water (WUE), nitrogen (NUE), and CO2 in well-watered plants. When supplied in a beneficial range of 1-5 mM, Cl- increases leaf cell size, improves leaf osmoregulation, and reduces water consumption without impairing photosynthetic efficiency, resulting in overall higher WUE. Thus, adequate management of Cl- nutrition arises as a potential strategy to increase the ability of plants to withstand water deficit. To study the relationship between Cl- nutrition and drought resistance, tobacco plants treated with 0.5-5 mM Cl- salts were subjected to sustained water deficit (WD; 60% field capacity) and water deprivation/rehydration treatments, in comparison with plants treated with equivalent concentrations of nitrate, sulfate, and phosphate salts. The results showed that Cl- application reduced stress symptoms and improved plant growth during water deficit. Drought resistance promoted by Cl- nutrition resulted from the simultaneous occurrence of water deficit avoidance and tolerance mechanisms, which improved leaf turgor, water balance, photosynthesis performance, and WUE. Thus, it is proposed that beneficial Cl- levels increase the ability of crops to withstand drought, promoting a more sustainable and resilient agriculture.


Assuntos
Secas , Água , Cloretos , Fotossíntese , Folhas de Planta , Nicotiana
4.
Front Plant Sci ; 11: 442, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32528483

RESUMO

Chloride (Cl-) has traditionally been considered harmful to agriculture because of its toxic effects in saline soils and its antagonistic interaction with nitrate (NO3 -), which impairs NO3 - nutrition. It has been largely believed that Cl- antagonizes NO3 - uptake and accumulation in higher plants, reducing crop yield. However, we have recently uncovered that Cl- has new beneficial macronutrient, functions that improve plant growth, tissue water balance, plant water relations, photosynthetic performance, and water-use efficiency. The increased plant biomass indicates in turn that Cl- may also improve nitrogen use efficiency (NUE). Considering that N availability is a bottleneck for the plant growth, the excessive NO3 - fertilization frequently used in agriculture becomes a major environmental concern worldwide, causing excessive leaf NO3 - accumulation in crops like vegetables and, consequently, a potential risk to human health. New farming practices aimed to enhance plant NUE by reducing NO3 - fertilization should promote a healthier and more sustainable agriculture. Given the strong interaction between Cl- and NO3 - homeostasis in plants, we have verified if indeed Cl- affects NO3 - accumulation and NUE in plants. For the first time to our knowledge, we provide a direct demonstration which shows that Cl-, contrary to impairing of NO3 - nutrition, facilitates NO3 - utilization and improves NUE in plants. This is largely due to Cl- improvement of the N-NO3 - utilization efficiency (NUTE), having little or moderate effect on N-NO3 - uptake efficiency (NUPE) when NO3 - is used as the sole N source. Clear positive correlations between leaf Cl- content vs. NUE/NUTE or plant growth have been established at both intra- and interspecies levels. Optimal NO3 - vs. Cl- ratios become a useful tool to increase crop yield and quality, agricultural sustainability and reducing the negative ecological impact of NO3 - on the environment and on human health.

5.
Int J Mol Sci ; 20(19)2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31546641

RESUMO

Chloride (Cl-) has traditionally been considered a micronutrient largely excluded by plants due to its ubiquity and abundance in nature, its antagonism with nitrate (NO3-), and its toxicity when accumulated at high concentrations. In recent years, there has been a paradigm shift in this regard since Cl- has gone from being considered a harmful ion, accidentally absorbed through NO3- transporters, to being considered a beneficial macronutrient whose transport is finely regulated by plants. As a beneficial macronutrient, Cl- determines increased fresh and dry biomass, greater leaf expansion, increased elongation of leaf and root cells, improved water relations, higher mesophyll diffusion to CO2, and better water- and nitrogen-use efficiency. While optimal growth of plants requires the synchronic supply of both Cl- and NO3- molecules, the NO3-/Cl- plant selectivity varies between species and varieties, and in the same plant it can be modified by environmental cues such as water deficit or salinity. Recently, new genes encoding transporters mediating Cl- influx (ZmNPF6.4 and ZmNPF6.6), Cl- efflux (AtSLAH3 and AtSLAH1), and Cl- compartmentalization (AtDTX33, AtDTX35, AtALMT4, and GsCLC2) have been identified and characterized. These transporters have proven to be highly relevant for nutrition, long-distance transport and compartmentalization of Cl-, as well as for cell turgor regulation and stress tolerance in plants.


Assuntos
Osmorregulação/fisiologia , Plantas/metabolismo , Cloreto de Sódio/metabolismo , Transporte de Íons/genética , Transporte de Íons/fisiologia , Micronutrientes/metabolismo , Nitratos/metabolismo , Nitrogênio/metabolismo , Nutrientes/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Salinidade , Transdução de Sinais , Água/metabolismo
6.
Plant J ; 99(5): 815-831, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31148340

RESUMO

Chloride (Cl- ) has been recently described as a beneficial macronutrient, playing specific roles in promoting plant growth and water-use efficiency (WUE). However, it is still unclear how Cl- could be beneficial, especially in comparison with nitrate (NO3- ), an essential source of nitrogen that shares with Cl- similar physical and osmotic properties, as well as common transport mechanisms. In tobacco plants, macronutrient levels of Cl- specifically reduce stomatal conductance (gs ) without a concomitant reduction in the net photosynthesis rate (AN ). As stomata-mediated water loss through transpiration is inherent in the need of C3 plants to capture CO2 , simultaneous increase in photosynthesis and WUE is of great relevance to achieve a sustainable increase in C3 crop productivity. Our results showed that Cl- -mediated stimulation of larger leaf cells leads to a reduction in stomatal density, which in turn reduces gs and water consumption. Conversely, Cl- improves mesophyll diffusion conductance to CO2 (gm ) and photosynthetic performance due to a higher surface area of chloroplasts exposed to the intercellular airspace of mesophyll cells, possibly as a consequence of the stimulation of chloroplast biogenesis. A key finding of this study is the simultaneous improvement of AN and WUE due to macronutrient Cl- nutrition. This work identifies relevant and specific functions in which Cl- participates as a beneficial macronutrient for higher plants, uncovering a sustainable approach to improve crop yield.


Assuntos
Dióxido de Carbono/metabolismo , Cloretos/metabolismo , Nicotiana/metabolismo , Nutrientes/metabolismo , Água , Cloretos/farmacologia , Cloroplastos/metabolismo , Difusão , Células do Mesofilo/metabolismo , Nitrogênio , Osmose , Fotossíntese , Folhas de Planta/metabolismo , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/crescimento & desenvolvimento , Estômatos de Plantas/metabolismo , Nicotiana/efeitos dos fármacos , Nicotiana/crescimento & desenvolvimento
7.
Plant Physiol ; 180(4): 2198-2211, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31164395

RESUMO

Root water uptake is influenced by root system architecture, which is determined by root growth and branching and the hydraulics of root cells and tissues. The phytohormone abscisic acid (ABA) plays a major role in the adaptation of plants to water deficit (WD). Here we addressed at the whole-root level in Arabidopsis (Arabidopsis thaliana) the regulatory role of ABA in mechanisms that determine root hydraulic architecture. Root system architecture and root hydraulic conductivity (Lpr) were analyzed in hydroponically grown plants subjected to varying degrees of WD induced by various polyethylene glycol (PEG) concentrations. The majority of root traits investigated, including first- and second-order lateral root production and elongation and whole-root hydraulics, had a bell-shaped dependency on WD, displaying stimulation under mild WD conditions (25 g PEG L-1) and repression under more severe conditions. These traits also showed a bell-shaped dependency on exogenous ABA, and their regulation by WD was attenuated in genotypes altered in ABA biosynthesis and response. Thus, we propose that ABA acts as a coordinator and an integrator of most root responses to mild and moderate WD, whereas responses to strong WD (150 g PEG L-1) are largely ABA independent. We also found that roots exhibit different growth responses to both WD and ABA depending on their rank and age. Taken together, our results give further insights into the coordinated water acquisition strategies of roots deployed in relation to WD intensity.


Assuntos
Ácido Abscísico/metabolismo , Raízes de Plantas/metabolismo , Água/metabolismo , Regulação da Expressão Gênica de Plantas , Polietilenoglicóis/metabolismo
8.
Front Plant Sci ; 10: 1619, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31921262

RESUMO

Drought is now recognized as the abiotic stress that causes most problems in agriculture, mainly due to the strong water demand from intensive culture and the effects of climate change, especially in arid/semi-arid areas. When plants suffer from water deficit (WD), a plethora of negative physiological alterations such as cell turgor loss, reduction of CO2 net assimilation rate, oxidative stress damage, and nutritional imbalances, among others, can lead to a decrease in the yield production and loss of commercial quality. Nutritional imbalances in plants grown under drought stress occur by decreasing water uptake and leaf transpiration, combined by alteration of nutrient uptake and long-distance transport processes. Plants try to counteract these effects by activating drought resistance mechanisms. Correct accumulation of salts and water constitutes an important portion of these mechanisms, in particular of those related to the cell osmotic adjustment and function of stomata. In recent years, molecular insights into the regulation of K+, Cl-, and water transport under drought have been gained. Therefore, this article brings an update on this topic. Moreover, agronomical practices that ameliorate drought symptoms of crops by improving nutrient homeostasis will also be presented.

9.
Curr Biol ; 26(16): 2213-20, 2016 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-27397895

RESUMO

Higher plants take up nutrients via the roots and load them into xylem vessels for translocation to the shoot. After uptake, anions have to be channeled toward the root xylem vessels. Thereby, xylem parenchyma and pericycle cells control the anion composition of the root-shoot xylem sap [1-6]. The fact that salt-tolerant genotypes possess lower xylem-sap Cl(-) contents compared to salt-sensitive genotypes [7-10] indicates that membrane transport proteins at the sites of xylem loading contribute to plant salinity tolerance via selective chloride exclusion. However, the molecular mechanism of xylem loading that lies behind the balance between NO3(-) and Cl(-) loading remains largely unknown. Here we identify two root anion channels in Arabidopsis, SLAH1 and SLAH3, that control the shoot NO3(-)/Cl(-) ratio. The AtSLAH1 gene is expressed in the root xylem-pole pericycle, where it co-localizes with AtSLAH3. Under high soil salinity, AtSLAH1 expression markedly declined and the chloride content of the xylem sap in AtSLAH1 loss-of-function mutants was half of the wild-type level only. SLAH3 anion channels are not active per se but require extracellular nitrate and phosphorylation by calcium-dependent kinases (CPKs) [11-13]. When co-expressed in Xenopus oocytes, however, the electrically silent SLAH1 subunit gates SLAH3 open even in the absence of nitrate- and calcium-dependent kinases. Apparently, SLAH1/SLAH3 heteromerization facilitates SLAH3-mediated chloride efflux from pericycle cells into the root xylem vessels. Our results indicate that under salt stress, plants adjust the distribution of NO3(-) and Cl(-) between root and shoot via differential expression and assembly of SLAH1/SLAH3 anion channel subunits.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Canais Iônicos/genética , Ânions/metabolismo , Proteínas de Arabidopsis/metabolismo , Canais Iônicos/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Tolerância ao Sal
10.
J Exp Bot ; 67(3): 873-91, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26602947

RESUMO

Chloride (Cl(-)) is a micronutrient that accumulates to macronutrient levels since it is normally available in nature and actively taken up by higher plants. Besides a role as an unspecific cell osmoticum, no clear biological roles have been explicitly associated with Cl(-) when accumulated to macronutrient concentrations. To address this question, the glycophyte tobacco (Nicotiana tabacum L. var. Habana) has been treated with a basal nutrient solution supplemented with one of three salt combinations containing the same cationic balance: Cl(-)-based (CL), nitrate-based (N), and sulphate+phosphate-based (SP) treatments. Under non-saline conditions (up to 5 mM Cl(-)) and no water limitation, Cl(-) specifically stimulated higher leaf cell size and led to a moderate increase of plant fresh and dry biomass mainly due to higher shoot expansion. When applied in the 1-5 mM range, Cl(-) played specific roles in regulating leaf osmotic potential and turgor, allowing plants to improve leaf water balance parameters. In addition, Cl(-) also altered water relations at the whole-plant level through reduction of plant transpiration. This was a consequence of a lower stomatal conductance, which resulted in lower water loss and greater photosynthetic and integrated water-use efficiency. In contrast to Cl(-), these effects were not observed for essential anionic macronutrients such as nitrate, sulphate, and phosphate. We propose that the abundant uptake and accumulation of Cl(-) responds to adaptive functions improving water homeostasis in higher plants.


Assuntos
Tamanho Celular/efeitos dos fármacos , Cloretos/farmacologia , Nicotiana/citologia , Nicotiana/fisiologia , Folhas de Planta/citologia , Água/metabolismo , Ânions , Cátions , Osmose/efeitos dos fármacos , Fosfatos/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/fisiologia , Sulfatos/farmacologia , Nicotiana/efeitos dos fármacos
11.
Reprod Sci ; 22(10): 1262-71, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25736327

RESUMO

Tubal ligation keeps the fimbriated end of the fallopian tube intact while interrupting the conduit for sperm and egg between the uterus and ovary. Tubal ligation is associated with an approximately 20% decreased risk of high-grade serous ovarian cancers, which mounting evidence suggests arise from the distal fallopian tube epithelium. We postulated that biological changes at the epithelial cellular level of the distal fallopian tube may account for the surgical procedure's observed risk reduction. We compared the histology, presence of epithelial progenitors (basally located CD44-positive cells), and degree of epithelial proliferation (Ki67-positive cells) of distal fallopian tube from 10 patients with previous tubal ligation and 10 age-matched patients with uncut fallopian tubes. A significantly reduced population of proliferating epithelial progenitors (basally located CD44/Ki67 dual-positive cells) was detected in the tubal ligated specimens (P = .0002). To functionally assess the effect of tubal ligation, a murine model was utilized to compare the growth capacity of distal fallopian tube epithelial cells isolated from either ligated or sham-operated tubal epithelia. Murine fallopian tube epithelial cells isolated after tubal ligation showed a significantly reduced capacity to grow organoids in culture compared to sham-operated controls (P = .002). The findings of this study show that tubal ligation is associated with a reduced presence and decreased proliferation of progenitor cells in the distal fallopian tube epithelium. These compositional and functional changes suggest that tubal ligation induces quiescence of distal fallopian tube epithelial cells.


Assuntos
Proliferação de Células , Senescência Celular , Células Epiteliais/patologia , Tubas Uterinas/cirurgia , Células-Tronco/patologia , Esterilização Tubária , Adulto , Animais , Biomarcadores/metabolismo , Células Cultivadas , Células Epiteliais/metabolismo , Tubas Uterinas/metabolismo , Tubas Uterinas/patologia , Feminino , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Receptores de Hialuronatos/metabolismo , Antígeno Ki-67/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pessoa de Meia-Idade , Estudos Retrospectivos , Células-Tronco/metabolismo , Fatores de Tempo , Proteína Vermelha Fluorescente
12.
Mol Cancer Ther ; 12(12): 2917-28, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24222661

RESUMO

Earlier in vitro work demonstrated that PARP inhibition induces cell death in PTEN-null endometrial cancer cell lines, but the in vivo therapeutic efficacy of these agents against endometrial cancer remains unknown. Here, we test the efficacy of AZD2281 (olaparib), an oral PARP inhibitor, in the therapy of PTEN-null endometrial tumors in a preclinical endometrial cancer mouse model. Primary endometrial tumors were generated by epithelial loss of PTEN using an in vivo model. This model recapitulates epithelial-specific loss of PTEN seen in human tumors, and histologically resembles endometrioid carcinomas, the predominant subtype of human endometrial cancers. Olaparib was administered orally to tumor-bearing mice in two hormonal extremes: high or low estrogen. Olaparib treatment achieved a significant reduction in tumor size in a low estrogenic milieu. In striking contrast, no response to olaparib was seen in tumors exposed to high levels of estrogen. Two key observations were made when estrogen levels were dropped: (i) the serum concentration of olaparib was significantly increased, resulting in sustained PARP inhibition at the tumor bed; and (ii) the homologous recombination pathway was compromised, as evidenced by decreased Rad51 protein expression and function. These two mechanisms may account for the sensitization of PTEN-null tumors to olaparib with estrogen deprivation. Results of this preclinical trial suggest that orally administered PARP inhibitors in a low estrogenic hormonal milieu can effectively target PTEN-null endometrial tumors. Extension of this work to clinical trials could personalize the therapy of women afflicted with advanced endometrial cancer using well-tolerated orally administered therapeutic agents.


Assuntos
Neoplasias do Endométrio/genética , Neoplasias do Endométrio/metabolismo , Estrogênios/sangue , PTEN Fosfo-Hidrolase/deficiência , Poli(ADP-Ribose) Polimerases/metabolismo , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacologia , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias do Endométrio/tratamento farmacológico , Neoplasias do Endométrio/patologia , Feminino , Camundongos , Camundongos Knockout , Modelos Biológicos , PTEN Fosfo-Hidrolase/genética , Ftalazinas/administração & dosagem , Ftalazinas/farmacologia , Piperazinas/administração & dosagem , Piperazinas/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases , Rad51 Recombinase/metabolismo , Carga Tumoral/efeitos dos fármacos , Carga Tumoral/genética
13.
Cancer Res ; 73(15): 4697-710, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23744837

RESUMO

Progesterone, an agonist for the progesterone receptor (PR), can be an efficacious and well-tolerated treatment in endometrial cancer. The clinical use of progesterone is limited because of the lack of biomarkers that predict hormone sensitivity. Despite its efficacy in cancer therapy, mechanisms and site of action for progesterone remain unknown. Using an in vivo endometrial cancer mouse model driven by clinically relevant genetic changes but dichotomous responses to hormonal therapy, we show that signaling through stromal PR is necessary and sufficient for progesterone antitumor effects. Endometrial cancers resulting from epithelial loss of PTEN (PTENKO) were hormone sensitive and had abundant expression of stromal PR. Stromal deletion of PR as a single genetic change in these tumors induced progesterone resistance indicating that paracrine signaling through the stroma is essential for the progesterone therapeutic effects. A hormone-refractory endometrial tumor with low levels of stromal PR developed when activation of KRAS was coupled with PTEN-loss (PTENKO/Kras). The innate progesterone resistance in PTENKO/Kras tumors stemmed from methylation of PR in the tumor microenvironment. Add-back of stromal PR expressed from a constitutively active promoter sensitized these tumors to progesterone therapy. Results show that signaling through stromal PR is sufficient for inducing hormone responsiveness. Our findings suggest that epigenetic derepression of stromal PR could be a potential therapeutic target for sensitizing hormone-refractory endometrial tumors to progesterone therapy. On the basis of these results, stromal expression of PR may emerge as a reliable biomarker in predicting response to hormonal therapy.


Assuntos
Resistencia a Medicamentos Antineoplásicos/fisiologia , Neoplasias do Endométrio/metabolismo , Receptores de Progesterona/metabolismo , Transdução de Sinais/fisiologia , Microambiente Tumoral/fisiologia , Animais , Western Blotting , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias do Endométrio/genética , Feminino , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , PTEN Fosfo-Hidrolase/biossíntese , PTEN Fosfo-Hidrolase/genética , Reação em Cadeia da Polimerase , Progesterona/farmacologia , Células Estromais/metabolismo , Microambiente Tumoral/efeitos dos fármacos
14.
J Sci Food Agric ; 93(2): 324-31, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22752850

RESUMO

BACKGROUND: A major problem in common bean (Phaseolus vulgaris L.) agriculture is the low yield due to terminal drought. Because common beans are grown over a broad variety of environments, the study of drought-resistant genotypes might be useful to identify distinctive or common mechanisms needed for survival and seed production under drought. RESULTS: In this study the relationship between terminal drought resistance and some physiological parameters was analysed using cultivars contrasting in their drought response from two different gene pools. Trials were performed in three environments. As expected, drought treatments induced a decrease in leaf relative humidity and an increase in leaf temperature; however, when these parameters were compared between susceptible and resistant cultivars under optimal irrigation and drought, no significant differences were detected. Similar results were obtained for chlorophyll content. In contrast, analysis of relative water content (RWC) and stomatal conductance values showed reproducible significant differences between susceptible and resistant cultivars grown under optimal irrigation and drought across the different environments. CONCLUSIONS: The data indicate that drought-resistant cultivars maximise carbon uptake and limit water loss upon drought by increasing stomatal closure during the day and attaining a higher RWC during the night as compared with susceptible cultivars, suggesting a water balance fine control to achieve enough yield under drought.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Secas , Phaseolus/crescimento & desenvolvimento , Folhas de Planta/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento , Água/metabolismo , Biomarcadores/metabolismo , Ciclo do Carbono , Clorofila/biossíntese , Produtos Agrícolas/metabolismo , Temperatura Alta/efeitos adversos , México , Phaseolus/metabolismo , Folhas de Planta/metabolismo , Reprodutibilidade dos Testes , Sementes/metabolismo , Especificidade da Espécie , Propriedades de Superfície
15.
Plant Physiol Biochem ; 56: 24-34, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22579941

RESUMO

Terminal drought is a major problem for common bean production because it occurs during the reproductive stage, importantly affecting seed yield. Diverse common bean cultivars with different drought susceptibility have been selected from different gene pools in several drought environments. To better understand the mechanisms associated with terminal drought resistance in a particular common bean race (Durango) and growth habit (type-III), we evaluated several metabolic and physiological parameters using two cultivars, Bayo Madero and Pinto Saltillo, with contrasting drought susceptibility. The common bean cultivars were submitted to moderate and severe terminal drought treatments under greenhouse conditions. We analyzed the following traits: relative growth rate, photosynthesis and transpiration rates, stomatal conductance, water-use efficiency, relative water content, proline accumulation, glycolate oxidase activity and their antioxidant response. Our results indicate that the competence of the drought-resistant cultivar (Pinto Saltillo) to maintain seed production upon terminal drought relies on an early response and fine-tuning of stomatal conductance, CO2 diffusion and fixation, and by an increased water use and avoidance of ROS accumulation.


Assuntos
Adaptação Fisiológica , Dióxido de Carbono/metabolismo , Secas , Phaseolus/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Água/metabolismo , Oxirredutases do Álcool/metabolismo , Antioxidantes/metabolismo , Biomassa , Phaseolus/classificação , Fotossíntese , Proteínas de Plantas/metabolismo , Estômatos de Plantas , Transpiração Vegetal , Prolina/metabolismo , Sementes , Especificidade da Espécie
16.
Int J Cardiovasc Imaging ; 28(4): 795-801, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21553076

RESUMO

To explore left ventricular filling patterns in patients with a history of previous myocardial infarction (MI) using time-volume curves obtained from conventional cine-cardiac magnetic resonance (CMR) examinations. Consecutive patients with a history of previous MI who were referred for CMR evaluation constituted the study population, and a consecutive cohort of sex and age-matched patients with a normal CMR constituted the control group. The following CMR diastolic parameters were evaluated: peak filling rate (PFR), time to PFR (tPFR), normalised PFR adjusted for diastolic volume at PFR (nPFR), and percent RR interval between end systole and PFR. Fifty patients were included, 25 with a history of previous MI and 25 control. The mean age was 59.6 ± 13.9 years and 27 (54%) were male. Within the control group, age was significantly related to PFR (r = -0.53, p = 0.007), whereas among patients with previous MI age was not related to PFR (r = -0.16, p = 0.44). PFR (252.4 ± 96.7 ml/s vs. 316.0 ± 126.4 ml/s, p = 0.05) and nPFR (1.6 ± 1.2 vs. 3.3 ± 1.5, p < 0.001) were significantly lower in patients with previous MI, whereas no significant differences were detected regarding tPFR (143.0 ± 67.5 ms vs. 176.2 ± 83.9 ms, p = 0.13) and % RR to PFR (18.1 ± 9.7% vs. 20.6 ± 12.2%, p = 0.44). MI size was related to LV ejection fraction (r = -0.76, p < 0.001), PFR (r = -0.40, p = 0.004), nPFR (r = -0.52, p < 0.001) and left atrium area (r = 0.40, p = 0.004). Patients at the lowest PFR quartile (<200 ml/s) showed a larger MI size (Q1 26.5 ± 25.5%, Q2 15.5 ± 20.9%, Q3 6.3 ± 12.4%, Q4 8.8 ± 14.1%, p = 0.04). At multivariate analysis, MI size was the only independent predictor of the lowest PFR (p = 0.017). Infarct size has an impact on LV filling profiles, as assessed by conventional cine CMR without additional specific pulse sequences.


Assuntos
Imagem Cinética por Ressonância Magnética , Infarto do Miocárdio/diagnóstico , Função Ventricular Esquerda , Adulto , Idoso , Argentina , Estudos de Casos e Controles , Distribuição de Qui-Quadrado , Estudos Transversais , Diástole , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Infarto do Miocárdio/fisiopatologia , Valor Preditivo dos Testes , Volume Sistólico , Sístole , Fatores de Tempo
17.
EuroIntervention ; 6(6): 773-8, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21205604

RESUMO

Guidance of percutaneous coronary interventions (PCI) by intravascular ultrasound (IVUS) provides more precise information in terms of quantitative measurement and qualitative assessment of coronary artery disease (CAD) than does conventional angiography. Several studies have tested the efficacy of IVUS to guide stent implantation. However, the conflicting results have left behind a continued debate as to whether IVUS-guided PCI has an impact on clinical outcome and angiographic restenosis. IVUS and computed tomography coronary angiography (CTCA) share the ability to evaluate the lumen along with the vessel wall, enabling characterisation of proximal and distal reference segments. Nevertheless, IVUS imaging is expensive and usually precluded in severe stenoses. In the present article, we discuss the potential application of CTCA for the guidance of PCI, particularly of complex lesions such as chronic total occlusions (CTO) and bifurcations.


Assuntos
Angioplastia Coronária com Balão , Angiografia Coronária/métodos , Doença da Artéria Coronariana/terapia , Interpretação de Imagem Radiográfica Assistida por Computador , Tomografia Computadorizada por Raios X , Doença da Artéria Coronariana/diagnóstico por imagem , Humanos , Imageamento Tridimensional , Seleção de Pacientes , Valor Preditivo dos Testes , Índice de Gravidade de Doença , Resultado do Tratamento , Ultrassonografia de Intervenção
18.
J Sci Food Agric ; 91(1): 152-62, 2011 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20853276

RESUMO

BACKGROUND: The aim of this study was to examine how different environmental factors (temperature, solar radiation, and vapour-pressure deficit [VPD]) influenced nutritional quality and flavour of cherry tomato fruits (Solanum lycopersicum L. cv. Naomi) grown in two types of experimental Mediterranean greenhouses: parral (low technology) and multispan (high technology). RESULTS: Fruits were sampled three times during 3 years (2004, 2005 and 2006): at the beginning, middle and end of the fruit production period. Values for temperature, solar radiation, and VPD peaked in the third sampling in both greenhouses; values were higher in the parral-type greenhouse, triggering abiotic stress. This stress reduced the accumulation of lycopene and essential elements, augmenting the phytonutrient content and the antioxidant capacity of tomatoes. During the third sampling, sugars were increased while organic acid content diminished, producing tomatoes with a sweeter-milder flavour. The parral greenhouse produced tomatoes with higher phenolic compounds and ascorbic acid contents, together with a greater antioxidant capacity, without showing differences in flavour parameters. CONCLUSION: The higher phytonutrients content and antioxidant activity during the environmental stress, more pronounced in parral than multispan greenhouse, together with the sweeter-milder flavour, conferred a notable nutritional benefit, which considerably improved the nutritional and organoleptic quality of these tomatoes.


Assuntos
Agricultura/métodos , Antioxidantes/metabolismo , Ambiente Controlado , Frutas/química , Solanum lycopersicum/química , Estresse Fisiológico , Paladar , Adaptação Fisiológica , Ácido Ascórbico/metabolismo , Carotenoides/metabolismo , Sacarose Alimentar/metabolismo , Frutas/classificação , Licopeno , Solanum lycopersicum/crescimento & desenvolvimento , Valor Nutritivo , Fenóis/metabolismo , Especificidade da Espécie , Luz Solar , Temperatura , Pressão de Vapor
19.
J Sci Food Agric ; 90(11): 1914-9, 2010 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-20602511

RESUMO

BACKGROUND: Currently, biofortification programmes are being carried out with selenium (Se), since it is an essential element for humans and its ingestion depends partly on a vegetable diet, this not being so for plants. In this sense, few studies have tested the effect that Se has on some of the main plant metabolisms, such as nitrogen (N) metabolism. Thus the aim of this study was to establish the effect of the application of different doses (5, 10, 20, 40, 60, 80 and 120 micromol L(-1)) and forms (selenate and selenite) of Se on the reduction of nitrate (NO3-) and subsequent assimilation of ammonium (NH4+). RESULTS: The results showed an increase in all enzyme activities analysed (nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS) and glutamate synthase (GOGAT)), especially with application of the selenite form, in addition to a decline in foliar NO3- concentration. CONCLUSION: Se applied in both forms increased N metabolism, with selenite inducing this physiological process more strongly, since it prompted a stronger activation of NR, GS and GOGAT as well as a greater concentration of total reduced N.


Assuntos
Enzimas/metabolismo , Lactuca/metabolismo , Nitrogênio/metabolismo , Folhas de Planta/metabolismo , Selênio/metabolismo , Nitratos/metabolismo , Selênio/farmacologia
20.
J Cardiovasc Comput Tomogr ; 4(2): 99-107, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20060800

RESUMO

BACKGROUND: Hypoenhanced regions on multidetector CT (MDCT) coronary angiography correlate with myocardial hyperperfusion. In addition to a limited capillary density, chronic myocardial infarction (MI) commonly contains a considerable amount of adipose tissue. OBJECTIVE: We explored whether regional myocardial hypoenhancement on contrast-enhanced MDCT could be identified with standard coronary artery calcium (CAC) scoring acquisitions with noncontrast CT. METHODS: Consecutive patients with a history of MI who were referred for contrast-enhanced MDCT from November 2006 until March 2009 were studied. Noncontrast CT for CAC scoring was also performed. The correlation between regional myocardial hypoenhancement on contrast-enhanced CT and regional myocardial hypoattenuated areas on noncontrast CT was defined. RESULTS: Eighty-three patients (mean age, 61.5+/-12.5 years; n=67; 81% male) with previous MI were studied. A total of 1411 myocardial segments were evaluated. Two hundred thirty-nine segments (17%) showed myocardial hypoenhancement by MDCT and 140 segments (9.6%) by CAC. On a patient level, noncontrast CT showed a sensitivity, specificity, positive predictive value, (PPV) and negative predictive value (NPV) of 66% (95% CI, 0.53-0.77), 100% (95% CI, 0.76-1.00), 100% (95% CI, 0.90-1.00), and 41% (95% CI, 0.26-0.58), respectively, to detect myocardial hypoenhancement. On a per segment level, noncontrast CT showed a sensitivity, specificity, PPV, and NPV of 58% (95% CI, 0.51-0.64), 100% (95% CI, 0.99-1.00), 99% (95% CI, 0.94-1.00), and 92% (95% CI, 0.90-0.93), respectively, to detect myocardial hypoenhancement. CONCLUSIONS: Our findings suggest that chronic MI can be detected with standard CAC scoring acquisitions.


Assuntos
Calcinose/diagnóstico por imagem , Angiografia Coronária/métodos , Infarto do Miocárdio/diagnóstico por imagem , Revascularização Miocárdica , Tomografia Computadorizada por Raios X/métodos , Tecido Adiposo/diagnóstico por imagem , Tecido Adiposo/patologia , Idoso , Calcinose/patologia , Doença Crônica , Meios de Contraste , Circulação Coronária , Vasos Coronários/patologia , Feminino , Coração/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/patologia , Miocárdio/patologia , Necrose , Estudos Retrospectivos , Função Ventricular Esquerda
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