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A Injúria Renal Aguda (IRA) é uma doença cujas principais causas são as doenças primárias, mas também pode ser resultado de terapias medicamentosas e procedimentos médicos. O aumento da expectativa de vida e consequente envelhecimento populacional, juntamente com maior incidência de condições comórbidas, principalmente Diabetes Mellitus (DM) e Hipertensão Arterial Sistêmica (HAS), pode levar ao desenvolvimento de Doença Renal Crônica (DRC) e, por conseguinte, ao desenvolvimento de Insuficiência Renal Aguda (IRA). Quanto à epidemiologia, a incidência de IRA é difícil de avaliar devido à falta de consenso em torno de sua definição. É importante que se estabeleça uma definição padrão para que possamos ter uma melhor compreensão da magnitude do problema. A incidência de infecções hospitalares depende de fatores como idade, sexo, comorbidades e local de internação dentro do hospital. Em países desenvolvidos, a incidência varia de 3 a 18,3%, enquanto em países menos desenvolvidos é de 21%. A IRA tem diversos subtipos que são importantes para identificar o prognóstico, as opções terapêuticas, as causas e outras condições associadas. Quanto às manifestações clínicas, incluem distúrbios neurológicos, cardiovasculares, respiratórios, hepáticos, digestivos, cutâneos e de mucosas e renais. O diagnóstico da IRA é feito com base na concentração sérica de creatinina ou na diminuição do débito urinário, para que o tratamento e prognóstico sejam melhores. Já a abordagem terapêutica, depende de vários fatores, incluindo idade, comorbidades crônicas, DRC subjacente, estágio e duração do episódio e gravidade da recuperação renal. Quanto mais grave, maior o risco de desfechos ruins. Para prevenir as IRA, é necessário realizar o manejo de fatores de risco modificáveis, como a retirada de medicamentos nefrotóxicos, o controle adequado de comorbidades pré-existentes, o controle precoce do foco infeccioso em casos de sepse, entre outros.

O acesso ao cuidado médico é essencial para o alcance da Atenção Primária à Saúde (APS) de qualidade. No Brasil, ainda persistem dificuldades de acesso. O Programa Médicos pelo Brasil (PMpB) pretende ampliar a oferta de serviços médicos em locais de difícil provimento ou alta vulnerabilidade. Ele traz como inovações a priorização das menores e mais isoladas cidades; a seleção de profissionais por processo isonômico; a formação em Medicina de Família e Comunidade e; a primeira carreira médica federal na APS, com salários competitivos, progressão e incentivos financeiros que valorizam a longitudinalidade e o desempenho. O PMpB é executado pela Agência para o Desenvolvimento da Atenção Primária à Saúde (Adaps), o que permite mais eficiência na gestão da política pública. Os primeiros nove meses do programa mostram resultados promissores, com aproximadamente 23 mil médicos interessados em ingressar no programa através de seu processo seletivo, 97,1% de ocupação das vagas e 95,4 % de permanência após o ingresso. Tais resultados sinalizam o avanço de qualidade do PMpB em relação às políticas anteriores, bem como a necessidade de continuar com sua implementação, a fim de que ela atinja todo o seu potencial de cobertura na APS do SUS.

International audience; The translocator protein (TSPO) is a ubiquitous transmembrane protein of great pharmacological interest thanks to its high affinity to many drug ligands. The only high-resolution 3D-structure known for mammalian TSPO was obtained by NMR for the mouse mTSPO in DPC detergent only in presence of the high-affinity PK 11195 ligand. An atomic structure of free-ligand mTSPO is still missing to better understand the interaction of ligands with mTSPO and their effects on the protein conformation.Here, we decipher the solution structures of the recombinant mTSPO without ligand both in (i) SDS, the detergent used to extract and purify the protein from E. coli inclusion bodies, and (ii) DPC, the detergent used to solve the PK 11195-binding mTSPO NMR structure.We report partially refolded and less flexible mTSPO helices in DPC compared to SDS. Besides, DPC stabilizes the tertiary structure of mTSPO, as shown by a higher intrinsic Trp fluorescence and changes in indole environment.We evaluate by SEC-MALLS that ∼135 SDS and ∼100 DPC molecules are bound to mTSPO. SEC-small-angle X-ray (SAXS) and neutron (SANS) scattering confirm a larger mTSPO-detergent complex in SDS than in DPC. Using the contrast-matching technique in SEC-SANS, we demonstrate that mTSPO conformation is more compact and less flexible in DPC than in SDS. Combining ab initio modeling with SANS, we confirm that mTSPO conformation is less elongated in DPC than in SDS. However, the free-ligand mTSPO envelope in DPC is not as compact as the PK 11195-binding protein NMR structure, the ligand stiffening the protein.

Oil palm produces the most consumed vegetable oil in the world. In addition to being economically viable and having multiple uses, the crop has a strong ecological appeal, given its high level of carbon sequestration, its low environmental impact, and a low mechanization level in the harvest process, generating income and financial sustainability for the inhabitants of that biome. However, despite the large areas suitable for cultivation in harmony with the forest in Brazil, oil palm production has been limited by a disease known as fatal yellowing (FY). In 30 years of research to determine the causal agent of this disease, many epidemiology studies with insects and plant pathogens have been performed, but there is no consensus on its cause. Abiotic factors have also started to be considered a possible cause of these symptoms. Therefore, to clarify the relationship of this disease to environmental variables, we studied the nutritional status of the plant, the soil class and fertility, the climatic variables and attempted to verify the set of proteins with higher levels in diseased palms showing FY symptoms and healthy palms. FY occurred under constant rain and in clay soils; consequently, the roots of these palm trees suffered anoxia, which caused nutritional problems and the increase in levels of stress-related proteins. Under these conditions, the usually observed symptom was yellowing, which can lead to the death of the plant, giving the disease its name. In other words, the symptomatic picture is not associated with only a biotic cause. Thus, a pedological survey of the area, planting in soils not subject to waterlogging or with good drainage conditions, and the correct maintenance of soil fertility and plant nutrition may certainly contribute to the management and reduction of fatal yellowing without the use of agrochemicals.

The present study had the objective to evaluate the effect of blends of KCl and K2SO4 fertilizers and their influence on the yield and the nutritional state of coffee plants, as well as on the chemical composition and quality of the coffee beverage. The experimental design was in randomized blocks with four repetitions and six treatments (T1: 100% KCl; T2: 75% KCl + 25% K2SO4; T3: 50% KCl + 50% K2SO4; T4: 25% KCl + 75% K2SO4; T5: 100% K2SO4; and a control, without application of K). The following analyses were performed: K and Cl content in the leaves and the soil, stocks of Cl in soil, yield, removal of K and Cl with the beans, cup quality of the beverage, polyphenol oxidase activity (PPO), electric conductivity (EC), potassium leaching (KL), the content of phenolic compounds, the content of total sugars (TS), and total titratable acidity (TTA). The stocks of Cl in the soil decreased as the proportion of KCl in the fertilizer was reduced. The fertilization with KCl reduces the cup quality and the activity of the polyphenol oxidase, probably due to the ion Cl. The increase in the application of Cl directly relates to the increase in potassium leaching, electric conductivity, and titratable acidity. Indirectly, these variables indicate damages to the cells by the use of Cl in the fertilizer. The activity of the polyphenol oxidase enzyme and the cup quality indicate that the ion Cl- reduces the quality of the coffee beverage. K content in the leaves was not influenced by the application of blends of K fertilizer while Cl content increased linearly with KCl applied. The application of KCl and K2SO4 blends influenced coffee yield and the optimum proportion was 25% of KCl and 75% of K2SO4. The highest score in the cup quality test was observed with 100% K2SO4.

Calonectria leaf spot, caused by Calonectria pteridis, is a serious problem in Eucalyptus crops in both nursery and the field. Under ideal conditions, the disease can cause severe defoliation. It is known that calcium and potassium are directly related to the plant's resistance to pathogens. Thus, the knowledge of how a balanced fertilization of Ca and K interferes in the distribution of these nutrients at the infection site would contribute to elucidate the resistance of the plant related to its nutrition. This study investigated the effect of calcium and potassium fertilizer application on the content and distribution of these nutrients in the symptomatic leaf area, transition zone and asymptomatic leaf area over time. Eucalyptus seedlings were grown in nutrient solution under different Ca and K treatments (6 mmol/L K + 4 mmol/L Ca, 6 mmol/L K + 8 mmol/L Ca and 9 mmol/L K + 12 mmol/L Ca) and inoculated with C. pteridis. Leaves were removed at 24, 48 and 72 hr after inoculation (hai) and evaluated by X‐ray microanalysis. The highest calcium content among the different leaf areas was observed in the symptomatic area, and the levels in this area increased over time, with the highest mean value observed at 72 hai in the 6K + 8Ca treatment. In the other treatments, the mean calcium content peaked at 48 hai and then decreased. A similar pattern in asymptomatic tissue was observed for potassium in the 6K + 8Ca treatment. Fertilization with calcium and potassium directly affected the demand and availability of nutrients at different times during infection. These results demonstrate that plant defence responses and their continuity over time during infection rely on balanced calcium and potassium fertilization because these nutrients are directly involved in plant resistance to the pathogen.

Providing adequate nutrition to coffee plants is required to maintain plant health. The effect of five doses (0.05, 0.25, 0.50, 1.0, 2.0 and 4.0 mg L−1) of boron (B), zinc (Zn) and manganese (Mn) on the severity of rust on coffee plants grown in nutrient solution was evaluated. Micronutrients were supplied to seedlings having two pairs of fully developed leaves. The seedling plants were inoculated with spores (106 ml−1) of the coffee rust pathogen (Hemileia vastatrix). Five assessments of the severity of the rust symptoms were made starting on the 43rd day after inoculation. The area under the disease progress curve for severity (AUDPCS) was calculated. There was a statistical difference in AUDPCS (p

Oil palm produces the most consumed vegetable oil in the world. In addition to being economically viable and having multiple uses, the crop has a strong ecological appeal, given its high level of carbon sequestration, its low environmental impact, and a low mechanization level in the harvest process, generating income and financial sustainability for the inhabitants of that biome. However, despite the large areas suitable for cultivation in harmony with the forest in Brazil, oil palm production has been limited by a disease known as fatal Yellowing (FY). In 30 years of research to determine the causal agent of this disease, many epidemiology studies with insects and plant pathogens have been performed, but there is no consensus on its cause. Abiotic factors have also started to be considered a possible cause of these symptoms. Therefore, to clarify the relationship of this disease to environmental variables, we studied the nutritional status of the plant, the soil class and fertility, the climatic variables and attempted to verify the set of proteins and their isoforms expressed in diseased palms showing FY symptoms and healthy palms. FY occurred under constant rain and in clay soils; consequently, the roots of these palm trees suffered anoxia, which caused nutritional problems and the accumulation of stress-related proteins. Under these conditions, the usually observed symptom was yellowing, which can lead to the death of the plant, giving the disease its name. In other words, the symptomatic picture is not associated with only a biotic cause. Thus, a pedological survey of the area, planting in soils not subject to waterlogging or with good drainage conditions, and the correct maintenance of soil fertility and plant nutrition may certainly contribute to the management of and reduction in fatal yellowing without the use of agrochemicals.

Diseases of the coffee plant can be effectively managed via well-balanced nutrition. This study assessed the effect of nitrogen and potassium fertilizers on the intensity of coffee (Coffea arabica) rust (Hemileia vastatrix) under greenhouse conditions. The susceptible cultivar New World 376/4 was used as the test species. Treatments included five N rates (3, 7, 11, 15 and 19 mmol L−1) with five K rates (3, 5, 7, 9 and 11 mmol L−1) in a 5 × 5 factorial design, for a total of 25 treatments and three replications with each treatment involving two plants growing in a nutrient solution. The completely randomized experimental design permitted evaluation of N and K on rust incidence and disease severity. The portion below the severity progress curve (AUDPCS) was calculated. Disease severity increased 16.48% with a dose of 7 mmol N L−1 and 11 mmol K L−1. There was an interaction of N with K in the AUDPCS and dried plant mass occurred. The AUDPCS (42.00) was lower when the next dose used was a combination of 19:07 mmol L−1 of N and K. A significant negative correlation was seen with the dry mass of the coffee seedlings.

Brown eye spot is one of the main diseases of coffee trees. The aim of this study was to evaluate the severity of brown eye spot in coffee plantations subjected to different drip irrigation and fertilization management. The study was carried out in Lavras-MG, Brazil, in a plantation of the cultivar MGS Travessia. Disease assessments were performed monthly from March 2012 to June 2014. The experimental design was a randomized block design with 12 treatments. The irrigation treatments were the control without irrigation, irrigation all year, suspension of irrigation for 30 days in July, and for 70 days between July and September. Fertilization treatments were recommended rate of NK fertilizer, high rate of NK plus P and high rate of NK. severity of the disease integrated into area under the disease progress curve (AUDPC). There was a difference in AUDPC in the evaluated years, reflecting the biennial characteristic of the coffee crop. There was no significant interaction between irrigation and fertilization. However, when irrigation and fertilization treatments where analyzed separately, the suspension of irrigation for 70 days between July and September in 2012 favored brown eye spot and in the same year the high rates of NK increased productivity.

Occurrence and intensity coffee leaf rust (Hemileia vastatrix) depend mainly on the irrigation system, soil fertility and plant nutrition. The aim of this study was to evaluate the spatial distribution of coffee leaf rust relative to soil fertility and plant nutrition in coffee plantations irrigated by drip and center pivot using geostatistics. The experiment was installed in two experimental areas, with a drip and center pivot irrigation system of 11 and 17 ha and 52 and 50 georeferenced sampling points, respectively. The incidence of the disease, soil fertility and plant nutritional status were evaluated at each point. For the drip system, there was no significant correlation between disease incidence and leaf contents of N, P, K, and Ca. Regarding fertility, there was a positive correlation only for P and the disease incidence. For the center pivot system, there was a positive correlation between coffee leaf rust and Ca, P, and K, and negative for P and K in the leaves, varying according to the assessment date. In soil, only Ca correlated negatively whereas K positively correlated with incidence. The spatial distribution of the disease and nutrients varied over the years, being observed a gradient from foci in the kriging maps elaborated after the adjustment of the exponential model.

Cell membranes represent a complex and variable medium in time and space of lipids and proteins. Their physico-chemical properties are determined by lipid components which can in turn influence the biological function of membranes. Here, we used hydrostatic pressure to study the close dynamic relationships between lipids and membrane proteins. Experiments on the β–barrel OmpX and the α–helical BLT2 G Protein-Coupled Receptor in nanodiscs of different lipid compositions reveal conformational landscapes intimately linked to pressure and lipids. Pressure can modify the conformational landscape of the membrane protein per se, but also increases the gelation of lipids, both being monitored simultaneously at high atomic resolution by NMR. Our study also clearly shows that a membrane protein can modulate, at least locally, the fluidity of the bilayer. The strategy proposed herein opens new perspectives to scrutinize the dynamic interplay between membrane proteins and their surrounding lipids.

G Protein-Coupled receptors represent the main communicating pathway for signals from the outside to the inside of most of eukaryotic cells. They define the largest family of integral membrane receptors at the surface of the cells and constitute the main target of the current drugs on the market. The low affinity leukotriene receptor BLT2 is a receptor involved in pro- and anti-inflammatory pathways and can be activated by various unsaturated fatty acid compounds. We present here the NMR structure of the agonist 12–HHT in its BLT2-bound state and a model of interaction of the ligand with the receptor based on a conformational homology modeling associated with docking simulations. Put into perspective with the data obtained with leukotriene B4, our results illuminate the ligand selectivity of BLT2 and may help define new molecules to modulate the activity of this receptor.

Brown eye spot is one of the most common and important diseases of coffee in Brazil. Using geostatistics, this study evaluated the spatio-temporal aspects of the disease and how they relate to plant nutrition and soil fertility in plots irrigated by center pivot and drip irrigation. The experiments were conducted in Carmo do Rio Claro City, in southern Minas Gerais state, southeast Brazil. The sampling grid was georeferenced with 50 points in 17 ha and 52 points in 11 ha for center pivot and drip irrigation, respectively. Disease incidence was assessed at 60-day intervals from August 2012 to March 2015. Yield, plant mineral nutrition, and soil fertility were evaluated at each point annually. Weather data were obtained from climatological stations with sensors for temperature, relative humidity, wind velocity, leaf wetness duration, and total precipitation that were located inside and outside the coffee canopy in both experimental plots. Climate data were correlated with disease incidence. Disease progress curves were plotted, and semivariogram models were fitted for assessments with a high disease incidence over time. Then, the data were interpolated by ordinary kriging, and maps of disease, yield, and leaf nutrients (B, P, and K) were constructed. The average temperatures and accumulated rainfall rates were lower in periods of higher incidence, but relative humidity was high. All variables exhibited space-time variation in both plots. There was a correlation (p

Soybeans (Glycine max) (V3 stage) were sprayed once with nanoparticles (NPs) of AgO, B, CeO, CuO, MnO, MoO3, SiO, TiO, or ZnO and exposed to Fusarium virguliforme, the cause of sudden death syndrome. Up to 80% root rot was observed in greenhouse experiments. However, NP CuO, B, MoO3, or ZnO reduced the root rot severity by 17–25%. Infected roots and shoots had significant changes in B, Mg, P, S, Si, and Zn, but NP treatment restored levels to that of the healthy control. For example, the increased root Mg and Mn contents induced by disease were reversed by NP B and Mn amendments. In vitro assays found that the NPs did not inhibit the pathogen. This, along with the restoration of altered nutrient levels in the plant tissue, suggests that modulated plant nutrition increased disease defense. Treatment of seedlings with nanoscale micronutrients may be a new tool in promoting soybean health.

Silicon (Si) is known to reduce the severity of pathogens on many plants. This study aimed to determine the effect of silicon (Si) in reducing the severity of yellow Sigatoka (Mycosphaerella musicola) on banana plants cultivated in nutrient solution. The treatments included five concentrations of silicic acid (H4SiO4): 0, 0.5, 1.0, 1.8 and 3.6 mmol L−1. The area under the disease severity progress curve (AUDSPC) was calculated for each treatment, and the nutrient content of the leaves determined. AUDSPC for plants receiving 3.05 mmol L−1 H4SiO4 was 49.27% lower compared to plants receiving no supplemental H4SiO4. In contrast, plants grown in a solution of 3.6 mmol L−1 H4SiO4 had 23.53% more Si content in the leaves compared to plants cultivated without supplemental H4SiO4. These results suggest Si could be used as a component in the integrated management of yellow Sigatoka.

The supply of nutrients in balanced proportions leads to greater crop yields and represents an alternative practice for the management of plant diseases. Accordingly, we investigated the effect of the doses of and the nutritional balance between calcium (Ca) and potassium (K) on the severity of leaf spot and defoliation caused by the fungus Calonectria pteridis. Moreover, the effect of the treatments on the growth of interspecific hybrid eucalyptus clone seedlings (Eucalyptus grandis Hill ex Maiden &times, E. urophylla S.T. Blake), which are highly susceptible to the disease, was evaluated. The 25 treatments comprised combinations of one of five doses of Ca (1.2, 3.0, 6.0, 9.0 and 12.0 mmol L&minus, 1) with one of five doses of K (0.8, 2.0, 4.0, 8.0 and 12.0 mmol L&minus, 1) and five replicates of each treatment were included in the study. The supply of high concentrations of K favoured C. pteridis infection and resulted in high disease severity, although defoliation was not observed. However, the supply of both nutrients in excess (12.0 mmol L&minus, 1 Ca &times, 9.0 mmol L&minus, 1 K) resulted in a higher disease severity and an increased defoliation percentage (82 and 64%, respectively). Defoliation not associated with Calonectria leaf blight disease was observed with the imbalanced treatments, that is, the treatments combining a low concentration of one nutrient and an excess concentration of the other nutrient. The supply of K at a level near the standard dose (6 mmol L&minus, 1) and of Ca at a dose above 4 mmol L&minus, 1 (standard dose) ensured high mean values for the morphological variables root and shoot biomass, plant height and chlorophyll a and b contents. These treatments also resulted in low disease severity and defoliation percentages, indicating that a balanced supply of Ca and K ensures reductions in disease severity and defoliation and contributes to higher growth.

Understanding the signal transduction mechanism mediated by the G Protein-Coupled Receptors (GPCRs) in eukaryote cells represents one of the main issues in modern biology. At the molecular level, various biophysical approaches have provided important insights on the functional plasticity of these complex allosteric machines. In this context, X-ray crystal structures published during the last decade represent a major breakthrough in GPCR structural biology, delivering important information on the activation process of these receptors through the description of the three-dimensional organization of their active and inactive states. In complement to crystals and cryo-electronic microscopy structures, information on the probability of existence of different GPCR conformations and the dynamic barriers separating those structural sub-states is required to better understand GPCR function. Among the panel of techniques available, nuclear magnetic resonance (NMR) spectroscopy represents a powerful tool to characterize both conformational landscapes and dynamics. Here, we will outline the potential of NMR to address such biological questions, and we will illustrate the functional insights that NMR has brought in the field of GPCRs in the recent years.

This study aimed at assessing the interaction of potassium (K) and boron (B) in the coffee rust intensity in a nutrient solution. The experiment which was performed in a greenhouse was set up in the randomized complete block design (DBC) with four replicates. The experimental unit involved a single vase with two Catuai Vermelho (IAC 144) cultivars. The treatments included five doses of boron (0.05, 0.50, 1, 2 and 4 mg L -1 ) and five of potassium (4.0, 5.0, 6.0, 7.0 and 8.0 mmol L -1 ), totaling to 25 treatments in a factorial variance analysis. All the coffee seedling leaves were inoculated with Hemileia vastatrix . For the next 24 hours, the vases were covered with a black plastic bag, and left in the greenhouse to ensure favorable conditions for the fungal infection. A significant interaction was observed between the potassium (K) and boron (B) nutrients in coffee rust intensity. As the boron dose increased from 0.05 to 2.0 mg L -1 , the coffee rust intensity was observed to rise. From the 0.50 mg L -1 dose of B a drastic drop in the dry plant mass was observed, which reached zero index at the highest boron dose due to phytotoxicity.

The objective of this work was to assess the incidence of Yellow Sigatoka in banana plants cultivated with deficiencies of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur or boron. The experimental design was a randomized complete block with 8 treatments, 4 repetitions and 1 plant per repetition. The treatments were supplied in solution culture and consisted of all the nutrients (control) or nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulphur (S) or boron (B) deficiency. Leaves 1 and 2 were inoculated on the abaxial surface with a suspension of conidia and assessed every 5 days to with a total of 5 assessments. The average number of lesions were integrated for the area under the disease progress curve (AUDPC). The greatest AUDPC occurred in plants deficient in K, N, P, S, or Mg. Plants deficient in N, P, K, Ca, Mg, S or B had lower leaf contents of these nutrients and showed morphological changes expressed in visual deficiency symptoms. Thus, banana plants deficient in K, N, P, S or Mg had a greater incidence of Yellow Sigatoka, compared with plants with full nutrients and plants deficient Ca or B.

This study analyzed the spatial distribution of Yellow Sigatoka Leaf Spot relative to soil fertility and plant nutritional status using geostatistics. The experimental area comprised 1.2 ha, where 27 points were georeferenced and spaced on a regular grid 18 × 18 m. The severity of Yellow Sigatoka, soil fertility and plant nutritional status were evaluated at each point. The spherical model was adjusted for all variables using restricted maximum likelihood. Kriging maps showed the highest infection rate of Sigatoka occurred in high areas of the field which had the highest concentration of sand, while the lowest disease was found in lower areas with lower silt, organic matter, total exchangeable bases, effective cation exchange capacity, base saturation, Ca and Mg in soil, and foliar sulfur (S). These results may help farmers manage Yellow Sigatoka disease more effectively, with balanced fertilization and reduced fungicide application. This practice minimizes the environmental impact and cost of production while contributing to production sustainability.

Knowing the structure and distribution of nutrients in plant tissues can clarify some mechanisms of pathogen attack in plants and plant defense against infection, thus helping management strategies. The aim of this study was verify differences in distribution of mineral nutrients in coffee leaf tissues around foliar lesions of bacterial blight of coffee, blister spot, cercospora leaf, phoma leaf spot and coffee leaf rust. Fragments of leaf tissue surrounding the lesions were dehydrated in silica gel, carbon covered and subjected to X-ray microanalysis (MAX). Thirty-three chemical elements were detected in leaf tissue; however, there was variation in potassium and calcium contents surrounding the lesions. The highest potassium content was found in asymptomatic tissues surrounding the lesions, decreasing toward the transition zone and reaching minimum content in symptomatic tissues. The highest calcium content was found in symptomatic tissues, decreasing toward the transition zone and reaching minimum content in asymptomatic tissues. Therefore, MAX can be used to analyze the composition and distribution of nutrients in plant tissues and, if associated with mineral nutrition, it may help understand host-pathogen relationships and plant disease management.

International audience; Mechanosensitive channels are detected in all cells and are speculated to play a key role in many functions including osmoregulation, growth, hearing, balance, and touch. In prokaryotic cells, a direct gating of mechanosensitive channels by membrane tension was clearly demonstrated because the purified channels could be functionally reconstituted in a lipid bilayer. No such evidence has been presented yet in the case of mechanosensitive channels from animal cells. TREK-1, a two-pore domain K(+) channel, was the first animal mechanosensitive channel identified at the molecular level. It is the target of a large variety of agents such as volatile anesthetics, neuroprotective agents, and antidepressants. We have produced the mouse TREK-1 in yeast, purified it, and reconstituted the protein in giant liposomes amenable to patch clamp recording. The protein exhibited the expected electrophysiological properties in terms of kinetics, selectivity, and pharmacology. Negative pressure (suction) applied through the pipette had no effect on the channel, but positive pressure could completely and reversibly close the channel. Our interpretation of these data is that the intrinsic tension in the lipid bilayer is sufficient to maximally activate the channel, which can be closed upon modification of the tension. These results indicate that TREK-1 is directly sensitive to membrane tension.