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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.

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.

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.

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.

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.

Entre as estratégias para o controle da ferrugem da soja cita-se a nutrição mineral equilibrada. Objetivou-se, neste trabalho, verificar o efeito do cálcio e do potássio na severidade da ferrugem (Phakopsora pachyrhizi), na fotossíntese potencial e na nutrição de plantas de soja. O delineamento experimental foi em blocos casualizados, com 25 tratamentos, 4 repetições e 2 plantas por repetição. Utilizou-se esquema fatorial 5 x 5, com 5 doses de K (4, 5, 6, 7, 8 mmol L^-1), combinadas com 5 doses de Ca (3, 5, 7, 9, 11 mmol L^-1). As plantas foram inoculadas no estádio V4 e, após nove dias, iniciaram-se avaliações da severidade da ferrugem pelas porcentagens de tecido lesionado, as quais foram transformadas em área abaixo da curva de progresso da doença (AACPS).Também foram avaliados a fotossíntese potencial e o teor de nutrientes na matéria seca de raiz, caule e folhas. O suprimento de Ca reduziu a AACPS em todas as doses de K. O suprimento de K também reduziu a AACPS nas doses 5, 7 e 11 mmol L^-1 de Ca. A menor AACPS foi observada na combinação das doses de 8 e 11 mmol L^-1 de K e Ca, enquanto a maior AACPS foi observada nas doses de 4 e 5 mmol L^-1 de K e Ca. As plantas tratadas com as doses 6 e 5 mmol L^-1 de K e Ca e 5 e 5 mmol L^-1 de K e Ca apresentaram melhor resposta fotossintética. Com o incremento das doses de K na solução, houve aumento dos teores foliares de K e redução linear dos teores foliares de Ca. Com o incremento das doses de Ca em solução nutritiva verificaram-se aumentos nos teores desse elemento e redução linear dos teores de K nas folhas. A balanced mineral nutrition is among the strategies for the control of Asian soybean rust. This work aimed to evaluate the severity of the soybean rust (Phakopsora pachyrhizi), the potential photosynthesis and the nutrition of soybean plants with different levels of K and Ca. The experiment was arranged in a randomized block design with 25 treatments, 4 repetitions and 2 plants per repetition. A 5 x 5 factorial scheme with 5 doses of K (4, 5, 6, 7, 8 mmol L^-1) combined with 5 doses of Ca (3, 5, 7, 9, 11 mmol L^-1) was used. Plants were inoculated at growth stage V4 and after nine days weekly evaluations of disease severity were carried out using percentage of injured tissues, which were transformed into area under the disease progress curve (AUDPCS). Potential photosynthesis and nutrient content in the root, stem and leaf dry matter were also evaluated. The supply of Ca reduced AUDPCS at all doses of K. The supply of K also reduced the AUDPCS at the doses of 5, 7 and 11 mmol L^-1 of Ca. The smallest AUDPCS was observed at the combination 8 and 11 mmol L^-1 of K and Ca, respectively, while the largest AUDPCS was observed at the doses of 4 and 5 mmol L^-1 of K and Ca. The plants treated with 6 and 5 mmol L^-1 of K and Ca and 5 and 5 mmol L^-1 of K and Ca showed better photosynthetic response. Increasing doses of K in the solution promoted increase in K leaf contents and linear decrease in Ca leaf levels. Increasing the levels of Ca in nutrient solution promoted an increase in the content of this element and a linear reduction of K levels in the leaves.

Para quantificar a severidade da ferrugem, os teores de clorofilas a e b e os carotenóides e também a nutrição em plantas de soja supridas com silício, implantou-se um experimento em blocos casualizados com 6 tratamentos e 4 repetições. Os tratamentos consistiram em doses de silicato de potássio (0 mg/L, 56 mg/L, 112 mg/L, 168 mg/L, 224 mg/L e 280 mg/L). As plantas foram inoculadas no estádio V4. Nove dias após a inoculação, iniciaram-se as avaliações semanais do número de lesões de ferrugem da soja/cm² de área foliar, no total de cinco. Ao final do experimento, os dados foram integrados ao longo do tempo, obtendo-se a área abaixo da curva do número de lesões/cm² (AACNL). Após o término das avaliações, determinou-se a quantidade de clorofilas a e b, carotenóides e lignina das folhas das plantas de soja com as doses crescentes de silício. Os teores de macro e micronutrientes da parte aérea das plantas também foram analisados. Observou-se redução da AACNL com aumento das doses de silício na solução nutritiva. A AACNL reduziu, enquanto que os teores de fósforo, cálcio, enxofre e zinco, de clorofila b, carotenóides e lignina, na parte aérea, aumentaram com a adição de silício. Aiming to quantify the severity of Asian rust, the content of the chlorophylls a and b and carotenoids as well some nutritional aspects of soybean plants supplied with silicon in the form of soluble potassium silicate solution an experiment was carried out in a random block design with 6 treatments and four replicates. Treatments comprised potassium six silicate doses (0 mg/L, 56 mg/L, 112 mg/L, 168 mg/L, 224 mg/L and 280 mg/L). Plants were inoculated at the V4 stage and evaluated for rust severity five times starting at the 9th day after inoculation weekly. The severity data were integrated with time obtaining the area under the number lesions progress curve (AUNLC). At the end of experiment, shoots from plants that received increasing silicon doses were sampled in order to analyze the chlorophyll a and b, carotenoids, lignin, macro and micronutrients. Adding silicon reduced AUNLC and increase the level of chlorophyll b, carotenoids, lignin, P, Ca, S and Zn in soybean plants.

A dinâmica de adsorção / dessorção de ânions foi estudada como processos individuais na superfície de partículas de uma argila gibbsítica. Os dados sugerem um notável papel de gibbsita como retardante de lixiviação de nitrato no solo. O comportamento oposto do gibbsita em relação à adsorção / dessorção de silicato e fosfato sugere a necessidade de uma solução de compromisso adequada com relação às aplicações de intervalo e taxa de ânions em solos gibbsiticos cultivados. A alta adsorção de P verificada em valores de pH menores do que os relatados para o ponto de carga zero de hidróxidos de Al sintéticos, implica que este processo ocorre em gibbsites pedogênicos através da complexação da esfera interna. Made available in DSpace on 2018-10-24T00:32:11Z (GMT). No. of bitstreams: 1 PauloEmilioAdsorcaoporGibbsita.pdf: 297461 bytes, checksum: 5c2ce86ce74bf544309de05981f9efa2 (MD5) Previous issue date: 2009-12-10

A aplicação de silicatos pode promover incrementos na capacidade de troca de cátions, favorecer a disponibilização de ânions, especialmente o H2PO4- (fosfato diácido), elevar o pH, amenizar a toxidez de Al e, de maneira geral, incrementar a disponibilidade de nutrientes para as plantas, apresentando, porém, uma eficiência agronômica inferior em comparação aos carbonatos. Com o objetivo de avaliar o efeito da substituição do carbonato de Ca por silicato de Ca sobre as propriedades químicas dos solos, especialmente em relação à disponibilidade de P, foram realizados quatro experimentos em casa de vegetação, num delineamento inteiramente casualizado, com quatro repetições. Os tratamentos consistiram de cinco níveis de substituição (0, 25, 50, 75 e 100 %) do carbonato de Ca por silicato de Ca, mantendo uma relação estequiométrica Ca:Mg de 4:1 e o mesmo conteúdo de CaO, suficientes para elevar V = 60 %. Os tratamentos foram aplicados em amostras de 4 dm³ de Neossolo Quartzarênico órtico, Latossolo Vermelho-Amarelo textura média, Latossolo Vermelho-Amarelo textura argilosa e Latossolo Vermelho textura muito argilosa, sendo cada solo um experimento. Foram determinados os valores dos atributos químicos dos solos: pH em H2O, P, P remanescente (P-rem), K, Ca, Mg, Si, Al, H + Al, matéria orgânica (MO), Cu, Mn, Zn e B, soma de bases (S), a CTC efetiva (t), a CTC em pH 7,0 (T), a saturação por bases (V) e a saturação por Al (m), os quais foram submetidos à analise de variância e ao ajuste de modelos de regressão simples, considerando os níveis de substituição de CaCO3 por CaSiO3. Verificou-se que a substituição de carbonato por silicato promoveu aumentos significativos nos valores de Si, Al, H + Al e m e redução nos valores de P-rem, pH, S, t e V; já os valores de P Mehlich-1, K, Mg, MO, T, Mn, Cu e B não foram influenciados significativamente. Houve declínio na disponibilidade de Zn somente no solo RQo. A eficácia do silicato de Ca foi inferior à de carbonato de Ca na melhoria das condições químicas do solo.

O objetivo deste trabalho foi quantificar a retenção e a dessorção competitivas dos ânions nitrato, sulfato, silicato e fosfato na fração argila gibbsítica de um Gleissolo Melânico. Amostras da fração argila foram agitadas em tubos de centrífuga com solução de NaCl 30 mmol c L-1 contendo estes ânions em quantidades equivalentes a 30% das respectivas capacidades máximas de retenção exibidas pela argila. Para fins comparativos, as amostras foram agitadas com a mesma solução contendo 1 mmol c L-1 de cada um dos ânions citados. Os tubos foram centrifugados e determinaram-se as concentrações aniônicas nos sobrenadantes. A dessorção foi realizada agitando-se a fração argila remanescente nos tubos de centrífuga com a solução de NaCl, quantificando-se os ânions liberados. Em outro ensaio, com o silício e o fósforo previamente adsorvidos à gibbsita, adicionou-se, na seqüência, o fósforo e o silício intercalados para avaliar a capacidade de dessorver o ânion previamente adsorvido. O fosfato foi preferencialmente adsorvido em relação aos demais ânions estudados e a aplicação prévia de silício reduziu a fixação de fosfato. Desse modo, a aplicação de silício previamente à de fósforo favorece a fitodisponibilidade deste em solos altamente intemperizados. The objective of this work was to quantify the competitive retention and desorption of nitrate, sulfate, silicate and phosphate anions on gibbsitic clay fraction of a Melanic Gleisol. Samples of clay fraction were shaken in centrifuge tubes with 30 mmol c L-1 NaCl solution containing these anions in quantities equivalent to 30% of the respective maximum adsorption capacity exhibited by clay. For comparative purposes, samples were also shaken with the same solution containing 1 mmol c L-1 of each mentioned anion. The tubes were centrifuged and the anionic concentrations in supernatants were determined. The dessorption was performed by shaking the residual clay fraction in centrifuge tubes with NaCl solution and quantifying the released anions. In another experiment, with the silicon phosphorus previously adsorbed to gibbsite, P and Si were added in the sequence, intercalated for evaluating the capacity of desorpting the previously adsorbed anion. The phosphate was preferentially adsorbed in relation to the other studied anions and the previous silicon application reduced the phosphate fixation. The silicon application previously to phosphate favours the bioavailability of P in highly weathered soils.

Foram realizados três experimentos para estudar a influência do silício na redução da antracnose, causada por Colletotrichum lindemuthianum, em feijoeiro (Phaseolum vulgaris). No primeiro experimento plantas tratadas com silicato de cálcio foram inoculadas com 0, 10³, 10(4), 5x10(4), 10(5), 5x10(5) e 10(6) conídios/ml de C. lindemuthianum. Na concentração de 10(6) conídios/ml avaliou-se a diferença entre o silicato de cálcio e uma fonte de cálcio (óxido de cálcio). No segundo experimento foi avaliado o silicato de cálcio e de sódio na redução da antracnose. No terceiro experimento, por meio da microscopia eletrônica de varredura (MEV) e da microanálise de raios-X (MAX), estudou-se o efeito do silício nos mecanismos de resistência. Foram realizadas cinco avaliações da doença, utilizadas para calcular a área abaixo da curva de progresso da incidência (AACPI), da severidade (AACPS) e a duração da área foliar sadia (HAD), nos dois primeiros experimentos. Com o aumento da concentração do inóculo houve aumento na AACPI e AACPS e redução na HAD, porém a testemunha inoculada com a maior concentração de inóculo, e tratada apenas com cálcio (CaO), sem silicato, teve maiores AACPI e AACPS do que as plantas tratadas com silicato de cálcio. No segundo experimento, a menor AACPS e maior HAD foram obtidas no tratamento com silicato de sódio via foliar, que proporcionou redução de 62,4% na AACPS. Na MEV e na microanálise de raios X não se observaram a formação de barreira física e o acúmulo de silício externamente com a aplicação de silicato de cálcio, embora o elemento tenha contribuído para reduzir a antracnose. Three experiments were performed to study the influence of the silicon on the reduction of the common bean (Phaseolum vulgaris) anthracnose. The first experiment involved a plant fertilized with calcium silicate and different inoculum concentrations of the Colletotrichum lindemuthianum (0, 10³, 10(4), 5x10(4), 10(5), 5x10(5) and 10(6) conidia/ml). In the concentration 10(6) conidia/ml the difference between calcium silicate and calcium oxide was evaluated for effects on the disease. The second experiment evaluated the influence of sodium and calcium silicate on the reduction of the anthracnose. In the third experiment, the scanning electron microscopy (SEM) and X-ray micro-analysis (EDAX) were used to study the effect of the silicon on the plant resistance mechanism. Five evaluations of the incidence, severity and leaf area were done, in the first and second experiment. Disease evaluation was made using area under disease progress curve for incidence (AUDPCI) and severity (AUDPCS) and healthy leaf area duration (HAD). Inoculum concentration was found to increase the AUDPCI and AUDPCS. In contrast, the HAD had decreased. Fertilization of plants with calcium silicate significantly reduced the AUDPCI and AUDPCS, when compared to inoculated control and fertilized plants by calcium oxide (CaO) with higher inoculum concentration. On the second trial, the application of sodium silicate on the leaves of the bean plant reduced AUDPCS by 62,4% when compared to control. When the treated leaves were scanned with SEM and EDAX was performed, although the silicon had reduced the disease, no accumulation of an external silicon barrier was observed with application of the element.

O objetivo deste estudo foi avaliar o efeito dos silicatos de cálcio e de sódio sobre a intensidade da cercosporiose (Cercospora coffeicola) em mudas de cafeeiro (Coffea arabica), cultivar Catuaí IAC 99, nas doses 0; 0,32; 0,64; 1,26 g de SiO2.kg-1 de substrato. Foram realizadas cinco avaliações quinzenais nas quais se quantificou o número de plantas doentes, o número de folhas lesionadas por planta, o número de lesões por folha e o número total de lesões por planta. Essas avaliações foram utilizadas para construir a área abaixo da curva de progresso da doença. Ao término das avaliações, foram determinados os teores de macro, micronutrientes, silício e lignina na parte aérea das mudas de cafeeiro. A menor área abaixo da curva de progresso do total de lesões foi obtida com a dose de 0,84 g.kg-1 de silicato de sódio. Observou-se decréscimo linear para área abaixo da curva de progresso do número de plantas doentes e aumento na concentração de lignina nas folhas até a dose de 0,52 g.kg-1 de silicato de sódio, enquanto no caule houve acúmulo de SiO2 até 0,53 g.kg.-1. The objective of this work was to evaluate the effect of calcium and sodium silicate on the intensity of brown eye spot (Cercospora coffeicola) in coffee (Coffea arabica) seedlings (Catuaí IAC 99) by using doses (0; 0.32; 0.63 and 1.26 g of SiO2.kg-1) of substrate. Five evaluations were done by counting the number of diseased plants, number of leaves with lesions, number of lesions per leaf and total number of lesions per plant. The concentration of macro, micronutrients, silicon and lignin in the leaves was determined at the end of the experiment. The lowest area under the disease progress curve of the total number of lesions was observed with 0.84 g.kg-1 of sodium silicate. Diseased plants were found to have a linear decrease of area under the disease progress curve and an increase in the concentration of lignin up to the dose of 0.52 g.kg-1 of sodium silicate. The increase of sodium silicate and dose application into the soil up to 0.53 g.kg-1 decreased the concentration of SiO2 on the stem.

Overexpression of breast cancer resistance protein ABCG2 confers multidrug resistance in cancer cells. The GF120918-sensitive drug efflux activity of human wild-type (R482) ABCG2-transfected cells was used for rational screening of inhibitory flavonoids and establishment of structure-activity relationships. Flavones were found more efficient than flavonols, isoflavones, and flavanones. Differentially substituted flavone derivatives indicated positive OH effects at position 5, in contrast to positions 3 and 7. A methoxy at position 7 was slightly positive in tectochrysin, whereas a strong positive effect was produced by prenylation at position 6. The potency of 6-prenylchrysin was comparable with that of GF120918 (IC50 = 0.3 micromol/L). Both 6-prenylchrysin and tectochrysin seemed specific for ABCG2 because no interaction was detected with either P-glycoprotein or MRP1. The ABCG2 resistance profile in vitro is altered by mutation at amino acid 482. The R482T mutation limited the effect of prenylation on ABCG2 inhibition. Whereas GF120918 strongly inhibited the ATPase activity of wild-type ABCG2, neither 6-prenylchrysin nor tectochrysin altered the activity. In contrast, all three inhibitors stimulated the ATPase activity of mutant ABCG2. 6-Prenylchrysin at 0.5 micromol/L efficiently sensitized the growth of wild-type ABCG2-transfected cells to mitoxantrone, whereas higher concentrations were required for the mutant ones. In contrast, 1 micromol/L tectochrysin was sufficient to fully sensitize mutant ABCG2-transfected cells, whereas higher concentrations were required for the wild-type ones. Both flavones exhibited a lower intrinsic cytotoxicity than GF120918 and were apparently not transported by ABCG2. 6-Prenylchrysin and tectochrysin therefore constitute new and promising inhibitors for the reversal of ABCG2-mediated drug transport.Overexpression of breast cancer resistance protein ABCG2 confers multidrug resistance in cancer cells. The GF120918-sensitive drug efflux activity of human wild-type (R482) ABCG2-transfected cells was used for rational screening of inhibitory flavonoids and establishment of structure-activity relationships. Flavones were found more efficient than flavonols, isoflavones, and flavanones. Differentially substituted flavone derivatives indicated positive OH effects at position 5, in contrast to positions 3 and 7. A methoxy at position 7 was slightly positive in tectochrysin, whereas a strong positive effect was produced by prenylation at position 6. The potency of 6-prenylchrysin was comparable with that of GF120918 (IC50 = 0.3 micromol/L). Both 6-prenylchrysin and tectochrysin seemed specific for ABCG2 because no interaction was detected with either P-glycoprotein or MRP1. The ABCG2 resistance profile in vitro is altered by mutation at amino acid 482. The R482T mutation limited the effect of prenylation on ABCG2 inhibition. Whereas GF120918 strongly inhibited the ATPase activity of wild-type ABCG2, neither 6-prenylchrysin nor tectochrysin altered the activity. In contrast, all three inhibitors stimulated the ATPase activity of mutant ABCG2. 6-Prenylchrysin at 0.5 micromol/L efficiently sensitized the growth of wild-type ABCG2-transfected cells to mitoxantrone, whereas higher concentrations were required for the mutant ones. In contrast, 1 micromol/L tectochrysin was sufficient to fully sensitize mutant ABCG2-transfected cells, whereas higher concentrations were required for the wild-type ones. Both flavones exhibited a lower intrinsic cytotoxicity than GF120918 and were apparently not transported by ABCG2. 6-Prenylchrysin and tectochrysin therefore constitute new and promising inhibitors for the reversal of ABCG2-mediated drug transport.

A cercosporiose do cafeeiro (Coffea arabica), causada por Cercospora coffeicola, é uma das mais importantes doenças na fase de viveiro. O objetivo desse trabalho foi avaliar o efeito da aplicação de silício (1 g de CaSiO3 incorporada em 1 kg do substrato utilizado para encher os tubetes) no controle dessa doença em três variedades de cafeeiro (catuaí, mundo novo e icatú) e, determinar quais os possíveis fatores de resistência associados. As plantas com dois pares de folhas foram inoculadas com suspensão de 1,4 x 10(4) conídios de C. coffeicola por ml. Aos sete meses após a inoculação avaliaram-se a porcentagem de folhas lesionadas e o número total de lesões por planta. Após essa avaliação, retiraram-se amostras das folhas para o estudo em Microscopia Eletrônica de Varredura (MEV) e Microanálise de Raios-X (MAX). As plantas da variedade catuaí tratadas com silicato, tiveram redução de 63,2% nas folhas lesionadas e de 43% no total de lesões por planta, em relação à testemunha. A MAX e o mapeamento para Si indicaram distribuição uniforme do elemento em toda a superfície abaxial das folhas de cafeeiro nas três variedades tratadas. Nas folhas das plantas não tratadas, o Si foi raramente encontrado. Nas imagens de MEV também foi observada camada de cera bem desenvolvida na superfície inferior das folhas originárias de todas as plantas tratadas, sendo esta mais espessa em catuaí e rara ou ausente nas não tratadas.

Situada no sul de Minas Gerais, principal região cafeeira do país, a Clínica Fitossanitária da Universidade Federal de Lavras tem auxiliado os produtores, dando suporte na diagnose de doenças de origem biótica e abiótica, de modo a gerar subsídios para minimizar as perdas na produção. Nos últimos doze anos, foram analisadas 378 amostras de café. Em 78,6% das amostras, foram detectados fungos, destacando-se Colletotrichum sp. (29%), Rhizoctonia solani (18%), Cercospora coffeicola (13%), Phoma sp. (13%) e Fusarium sp (11%). Ocorreram ainda em números representativos casos de fitotoxidez, deficiência de nutrientes e problemas no sistema radicular. Devido à localização da Clínica, a maior parte das amostras foi proveniente de localidades na região sul do Estado (63%), seguido do Triângulo Mineiro (12%) e Zona da Mata (10%). The Phytossanitary Clinic of the Federal University of Lavras, situated in the south of the State of Minas Gerais has given support to coffee producers providing diagnoses of biotic and abiotic diseases, to generate subsidies to minimize losses in production of this crop. During the last twelve years, 378 samples have been analyzed. Fungi were detected in 78,6% of the samples. The major fungi found were Colletotrichum sp. (29%), Rhizoctonia solani (18%), Cercospora coffeicola (13%), Phoma sp. (13%), e Fusarium sp (11%). Other incidences were caused by phytotoxity, mineral deficiency and bad formation of the roots. Due to the location of the Phytossanitary Clinic, most of the samples came from locations of South of Minas Gerais (63%), followed by Triângulo Mineiro (12%) and Zona da Mata (10%).

The objective of this paper was to evaluate the potential of neural networks (NN) as an alternative method to the basic epidemiological approach to describe epidemics of coffee rust. The NN was developed from the intensities of coffee (Coffea arabica) rust along with the climatic variables collected in Lavras-MG between 13 February 1998 and 20 April 2001. The NN was built with climatic variables that were either selected in a stepwise regression analysis or by the Braincel® system, software for NN building. Fifty-nine networks and 26 regression models were tested. The best models were selected based on small values of the mean square deviation (MSD) and of the mean prediction error (MPE). For the regression models, the highest coefficients of determination (R²) were used. The best model developed with neural networks had an MSD of 4.36 and an MPE of 2.43%. This model used the variables of minimum temperature, production, relative humidity of the air, and irradiance 30 days before the evaluation of disease. The best regression model was developed from 29 selected climatic variables in the network. The summary statistics for this model were: MPE=6.58%, MSE=4.36, and R²=0.80. The elaborated neural networks from a time series also were evaluated to describe the epidemic. The incidence of coffee rust at four previous fortnights resulted in a model with MPE=4.72% and an MSD=3.95.

A ferrugem é a principal doença do cafeeiro, sendo sua ocorrência e intensidade afetada em razão do fornecimento de água e equilíbrio nutricional das plantas. Dessa forma objetivou-se avaliar a incidência da ferrugem, em lavoura cafeeira com diferentes manejos de irrigação e adubação. O estudo foi realizado em Lavras-MG, em cafeeiro da cultivar MGS Travessia. As avaliações da doença foram realizadas no período de março de 2012 a novembro de 2014. O delineamento experimental foi em blocos casualizados, com doze tratamentos, sendo 3 manejos de adubação, 4 manejos de irrigação e 3 repetições, totalizando 36 parcelas. O resultado referente a media da incidência da doença durante o período avaliado foi plotado em gráfico. Os dados de incidência foram integrados em área abaixo da curva de progresso da doença (AACPIF). Foi observada maior AACPIF (P

A nutrição equilibrada pode auxiliar no controle de doenças do cafeeiro. Assim, objetivou-se avaliar o efeito da adubação nitrogenada e potássica na intensidade da mancha aureolada do cafeeiro, em câmara de crescimento. Utilizou-se a cultivar Mundo Novo 376/4, suscetível à doença. Os tratamentos consistiram de cinco doses de N (3, 7, 11, 15 e 19 mmol L-1) combinadas com cinco doses de K (3, 5, 7, 9 e 11 mmol L-1), em esquema fatorial 5 x 5, totalizando 25 tratamentos e três repetições compostas por duas mudas em solução nutritiva. O delineamento experimental foi o inteiramente casualizado. Avaliou-se a incidência e a severidade da doença. A área abaixo da curva de progresso da incidência (AACPDI) e da severidade (AACPDS) foi calculada. Observou-se a maior incidência da doença (97,2%) na combinação das maiores doses de N e K. Houve diferença significativa apenas para o N na AACPDS, massa da planta seca e clorofilas a, b e total. A menor AACPDS (7,79) foi obtida com a dose 13,34 mmol L-1 de N. Houve correlação significativa e positiva para as clorofilas a, b e total com o N e a AACPS.

All prokaryotic nascent chains must be co-translationally deformylated to allow the further essential removal of the first methionine. This early nascent chain processing is ensured by peptide deformylases (PDFs), an enzyme shown to interact with ribosome at the exit tunnel. Recently, studies demonstrating in one hand the acquisition by different marine phages of modified version of bacterial PDF and in the other hand that also viral proteins undergo deformylation led to propose that phage PDFs could be important for viral fitness. Aside from this intriguing hypothesis, not much is known about these phage PDFs. Here, we show that most viral versions of the PDFs do not contain a C-terminal extension previously proposed to be responsible of direct PDF binding to ribosome. Nonetheless, we show that the smallest identified phage PDF, a fully C-terminally-truncated PDF, is still able to bind directly to ribosome via a new dedicated ribosome-binding domain, playing a master regulator function. Crosslinking expe...

The multidrug resistance phenotype of cancer cells has been often related to overexpression of plasma membrane ATP-binding cassette transporters, which are able to efflux many types of drug by using the energy of ATP hydrolysis. ABCG2 is a half-transporter recently involved. Its purification would help to understand the mechanism of both transport and its inhibition. Biophysical, structural, and functional studies are consuming great amounts of homogeneous purified proteins and require efficient overexpression systems. Heterologous overexpression of human membrane proteins is actually a challenge because these proteins are toxic for the host, and both translation and chaperone systems of the host are not well adapted to the biosynthesis of human proteins. Overexpression of ABCG2 has been assayed in both bacterial and insect cell/baculovirus systems. Although it was highly overexpressed in bacterial system, neither transport nor ATPase activity was found within inverted membrane vesicles. By contrast, insect cells/baculovirus system produces a low amount of protein, a part of which is active.

The multidrug resistance phenotype of cancer cells has been often related to overexpression of plasma membrane ATP-binding cassette transporters, which are able to efflux many types of drug by using the energy of ATP hydrolysis. ABCG2 is a half-transporter recently involved. Its purification would help to understand the mechanism of both transport and its inhibition. Biophysical, structural, and functional studies are consuming great amounts of homogeneous purified proteins and require efficient overexpression systems. Heterologous overexpression of human membrane proteins is actually a challenge because these proteins are toxic for the host, and both translation and chaperone systems of the host are not well adapted to the biosynthesis of human proteins. Overexpression of ABCG2 has been assayed in both bacterial and insect cell/baculovirus systems. Although it was highly overexpressed in bacterial system, neither transport nor ATPase activity was found within inverted membrane vesicles. By contrast, insect cells/baculovirus system produces a low amount of protein, a part of which is active.

O objetivo deste trabalho foi avaliar o efeito do silicato de cálcio e do sulfato de cobre na intensidade da antracnose e no teor nutricional do feijoeiro. O experimento foi conduzido em blocos casualizados em arranjo fatorial 4 x 4 (quatro doses de silicato de cálcio, com quatro doses de sulfato de cobre) e dois tratamentos adicionais (plantas não-inoculadas e plantas pulverizadas com Benomyl). Foram feitas quatro avaliações da incidência e da severidade da doença, além de se mensurar a área foliar total. Ao término das avaliações, os dados de incidência e de severidade foram integrados ao longo do tempo, obtendo-se a área abaixo da curva de progresso da incidência (AACPI) e da severidade (AACPS). Os teores de N, P, K, Ca, Mg, B, Cu, Fe, Mn, Zn, Si e lignina foram avaliados na parte aérea. Observou-se decréscimo linear da AACPI com o aumento das doses de silicato de cálcio. Com o aumento das doses de cobre, houve redução de 35% na AACPS. O suprimento de silicato e de cobre alterou o teor de K, Mg, S, Zn, Ca e Si da parte aérea do feijoeiro. The objective of this work was to evaluate the effect of calcium silicate and copper sulfate on anthracnose intensity and nutrition of bean plants. The experiment was conducted using an experimental design in randomized blocks following a 4 x 4 factorial arrangement, (four levels of calcium silicate and four levels of copper sulfate) and two additional treatments (plants without inoculation and plants sprinkled with Benomyl). Four evaluations of the incidence and severity of anthracnose were done, in addition to measuring total leaf area. At the end of the evaluations, incidence and severity data were integrated over time, obtaining the area under disease progress curve (AUDPC). Contents of N, P, K, Ca, Mg, B, Cu, Fe, Mn, Zn, Si and lignin were determined in the aerial part. A linear decrease of the intensity AUDPC was observed with the increase of the doses of calcium silicate. The severity AUDPC was influenced by the doses of copper, obtaining a reduction of 35% on the higher dosage. The supply of silicon and copper altered the content of the K, Mg, S, Zn, Ca and Si in the aerial part of the bean plants.

Para avaliar a dose e a forma de aplicação de sulfato de zinco foliar no crescimento e produtividade do cafeeiro Mundo Novo, instalou-se um experimento de campo em LATOSSOLO VERMELHO Distroférrico, na Fazenda Experimental da Epamig em São Sebastião do Paraíso. O delineamento experimental foi em blocos casualizados, em esquema fatorial 4 x 2, com cinco repetições e parcela de 30 plantas com seis úteis. As quantidades de sulfato de zinco (ZnSO4) foram aplicadas nas concentrações de 0; 0,5; 1,0 e 1,5%, testadas em duas ou quatro aplicações por ano agrícola. Foram avaliados por oito anos os teores foliares de P e Zn e as produções. Concluiu-se que o cafeeiro respondeu positivamente às aplicações de doses crescentes de ZnSO4 via foliar, aumentando a produção e também os teores foliares de Zn. Maior número de pulverizações de ZnSO4 em menores concentrações foi superior aos tratamentos com menor número de pulverizações mais concentradas, promovendo maiores produções. As produções máximas foram obtidas com doses de 10,8 e 12,6 kg ha-1 de ZnSO4, para duas e quatro aplicações anuais, respectivamente. Sugerem-se valores entre 10 e 28 mg kg-1 como faixa crítica foliar de Zn, e valores de 100 a 150 para relação P/Zn. Aiming to evaluate the dose and application schedule of foliar Zn-sulfate spraying in growing and yield of Arabic coffee Mundo Novo, a field experiment was set up on Distroferric Red Latosol, at the Experimental Station of the EPAMIG in São Sebastião do Paraíso. The statistical design used was randomized blocks in s 4 x 2 factorial scheme with five replications and a 30-plant plot with six central valid plants. Zinc sulfate (ZnSO4) was sprayed under 4 concentrations 0; 0.5; 1.0 and 1.5%, two or four applications per agricultural year. Phosphorus and zinc leaf levels were evaluated for eight years and the yields. It was possible to conclude that there is a positive response to the increasing concentrations of ZnSO4 applied on the leaves in terms of yield, and to Zn levels in the leaves. Four low concentrations sprayings promoted higher yields than two high concentrations. The highest yields were achieved with 10.8 and 12.6 kg ha-1 of ZnSO4, for 2 and 4 yearly applications, respectively. It is suggested as a critical range for the Zn leaves values between 10 and 28 mg kg-1 and for P/Zn ratio, between 100 and 150.

The multidrug transporter ABCG2, a membrane protein with six transmembrane segments, can be overexpressed with the baculovirus/insect cell system. However, ABCG2 is produced as two species with different migration behavior via SDS-PAGE. Evidences suggest that this is due to the accumulation of an immature ABCG2 species, since: (i) the upper species, with higher apparent molecular weight, was favored by treatments reducing the rate of protein synthesis; (ii) the lower species was accumulated in presence of an endoplasmic reticulum stress inducer, and could be converted into the upper species during electrophoresis with 9 M urea; (iii) each species was differently solubilized by detergents: the upper species was partially solubilized by non-ionic and zwitterionic detergents, whereas the lower one required stronger surfactants; (iv) membrane ATPase activity from infected insect cells was essentially associated to the upper species. Altogether, these results suggest that although the insect cell/baculovirus system is not ideally adapted to overexpress human ABCG2, it is able to produce appreciable amounts of purified protein and the addition of agents reducing the rate of protein synthesis improves the homogeneity, making it a suitable heterologous expression system.

Human ABCG2 was efficiently overexpressed in insect cell membranes, solubilized with 3-[(3-cholamidopropyl)dimethyl ammonio]-1-propanesulfonate, and purified through N-terminal hexahistidine tag. Its functionality was assessed by high vanadate-sensitive ATPase activity, and nucleotide-binding capacity. Interestingly, the R482T point mutation increased both maximal hydrolysis rate and affinity for MgATP, and lowered sensitivity to vanadate inhibition. Direct nucleotide binding, as monitored by quenching of intrinsic fluorescence, indicated a mutation-related preference for ATP over ADP. The R482T mutation only produced a limited change, if any, on the binding of drug substrates, indicating that methotrexate, on the one hand, and rhodamine 123 or doxorubicin, on the other hand, bound similarly to wildtype and mutant transporters whether or not they were subject to cellular transport. In addition, the characteristic inhibitors GF120918 and 6-prenylchrysin, which alter mitoxantrone efflux much better for wild-type than mutant ABCG2, bound similarly to purified ABCG2, while the highly-potent Ko143 bound in the nanomolar range also effective in inhibition of drug transport. All results indicate that the role of the arginine-482 mutation on substrate drug transport and inhibitor efficiency is not mediated by changes in drug binding. © Birkhäuser Verlag, 2006.

Corrigendum Corrigendum to ‘‘Overexpression of homogeneous and active ABCG2 in insect cells” [Protein Express. Purif. 63 (2009) 75–83] Alexandre Pozza , Jose M. Perez-Victoria , Attilio Di Pietro a,* a Proteines de resistanceaux agents chimiotherapeutiques, Equipe labellisee Ligue 2009, Institut de Biologie et Chimie des Proteines, UMR5086 CNRS-Universite Lyon 1 et IFR128 BioSciences Gerland-Lyon Sud, 7 Passage du Vercors, 69637 Lyon Cedex 07, Lyon, France b Instituto de Parasitologiay Biomedicina ‘Lopez-Neyra’, CSIC, Granada, Spain