Lime Rate in Clayey Soils Influences Chemical Fertility and Sugarcane Yield.

Liming contributes to the alleviation of acidity in highly weathered soils. For sugarcane, the use of green harvest methods and new soil tillage systems requires an adjustment of lime application rates. In the present study, the effects of different lime rates and tillage systems on sugarcane performance and soil chemical fertility parameters were assessed. Three experiments were conducted in two locations between April 2015 and October 2019. The study design was a randomized block field study with four replicates. Four lime rates were applied once at sugarcane establishments in each soil tillage system and location: no liming (control); lime recommended rate (LRR); two times LRR (2× LRR); and three times LRR (3× LRR). The three soil tillage systems were conventional (CT), deep-strip (DT), and modified deep-strip tillage (MDT). Soil chemical fertility, leaf nutrient concentrations, and sugarcane yield components were analyzed, and correlations were identified by principal component analysis (PCA). The soil acidity was adequately alleviated in all tillage systems. Increasing the lime rate improved the lime distribution and soil fertility parameters. Applying lime at rates higher than LRR improved stalk and sugar yields, longevity, agronomic efficiency index (AEI), and correlated with a longer residual effect of liming, mainly in the last ratoon.

Cardiomyocyte diffusible redox mediators control Trypanosoma cruzi infection: role of parasite mitochondrial iron superoxide dismutase.

Chagas disease (CD), caused by the protozoa Trypanosoma cruzi, is a chronic illness in which parasites persist in the host-infected tissues for years. T. cruzi invasion in cardiomyocytes elicits the production of pro-inflammatory mediators [TNF-α, IL-1ß, IFN-γ; nitric oxide (·NO)], leading to mitochondrial dysfunction with increased superoxide radical (O2·-), hydrogen peroxide (H2O2) and peroxynitrite generation. We hypothesize that these redox mediators may control parasite proliferation through the induction of intracellular amastigote programmed cell death (PCD). In this work, we show that T. cruzi (CL-Brener strain) infection in primary cardiomyocytes produced an early (24 h post infection) mitochondrial dysfunction with H2O2 generation and the establishment of an oxidative stress evidenced by FoxO3 activation and target host mitochondrial protein expression (MnSOD and peroxiredoxin 3). TNF-α/IL-1ß-stimulated cardiomyocytes were able to control intracellular amastigote proliferation compared with unstimulated cardiomyocytes. In this condition leading to oxidant formation, an enhanced number of intracellular apoptotic amastigotes were detected. The ability of H2O2 to induce T. cruzi PCD was further confirmed in the epimastigote stage of the parasite. H2O2 treatment induced parasite mitochondrial dysfunction together with intra-mitochondrial O2·- generation. Importantly, parasites genetically engineered to overexpress mitochondrial Fe-superoxide dismutase (Fe-SODA) were more infective to TNF-α/IL-1ß-stimulated cardiomyocytes with less apoptotic amastigotes; this result underscores the role of this enzyme in parasite survival. Our results indicate that cardiomyocyte-derived diffusible mediators are able to control intracellular amastigote proliferation by triggering T. cruzi PCD and that parasite Fe-SODA tilts the process toward survival as part of an antioxidant-based immune evasion mechanism.

Seeder performance under different pressures of vaccum and fuel consumption to soybean seeds / Deposição de sementes de soja em diferentes pressões de vácuo e consumo de combustível

In pneumatic precision seeders, the regularity in seeds deposition is essential for a proper sowing process. Thus, the aim of this study was to verify the accuracy in the soy beans seed capturing in different vacuum pressures (3.5 kPa; 4.0 kPa; 5.0 kPa; 5.5 kPa and 6.0 kPa), the seed distribution in the seed lines as well as the fuel consumption in the tractor-seed set. The experiment was carried out at the College of Agronomy ­ FCA/UNESP, Botucatu-SP. The outline was random blocks, in subplots layout banded of 30 × 3.15 m, with four replicates per treatment. A tractor-seeder set was used to collect the sample of fuel consumption and seed population. The real population of seed was collected in plastic bags fastened to the end of the conductor pipe, obtaining the population of the 5 central lines of the seeders. The acquisition of the fuel consumption data for each plot, was carried out using a flow meter. Thus, it was observed that the seeder distribution on the vacuum pressure at 3.5; 4.0 and 5.5 kPa decreased in the farthest lines when compared to the central lines. For the hourly fuel consumption, per area and also for the deposition of seeds the regularity in the distribution of seeds is affected when there is vacuum pressure below 5.0 kPa and, consequently, highest consumption. For soybean sowing, seeds having the characteristics described in this study, it is recommended to use vacuum pressure of 6.0 kPa. As a result, this vacuum pressure leads to the lowest fuel consumption per hour, 11.49 L h¯¹ and worked area, 7.35 L ha¯¹.

Nas semeadoras de precisão pneumáticas a regularidade na deposição de sementes é primordial para uma correta semeadura. Assim, o objetivo deste estudo foi verificar a acurácia na captura de sementes de soja em diferentes pressões de vácuo (3,5 kPa; 4 kPa; 5 kPa; 5,5 kPa e 6 kPa), a distribuição das sementes nas linhas da semeadora e, também, verificar o consumo de combustível do conjunto trator-semeadora. Realizou-se o experimento na Faculdade de Ciências Agronômicas ­ FCA/UNESP, Botucatu-SP. O delineamento experimental foi de blocos ao acaso, em esquema de subparcelas (faixas de 30 × 3,15 m), com quatro repetições por tratamento. Um conjunto trator-semeadora foi utilizado coletando-se as amostras de consumo de combustível e população de sementes. Sendo as sementes coletadas em sacos plásticos fixados ao final do tubo condutor, obtendo as populações das 5 linhas centrais da semeadora. A obtenção dos dados de consumo de combustível para cada parcela foi realizada utilizando-se um fluxômetro. Assim verificou-se que a distribuição de sementes nas pressões de vácuo 3,5; 4 e 5,5 kPa decrescem nas linhas mais distantes do centro da semeadora. Para o consumo de combustível horário, por área e deposição de sementes verifica-se que a regularidade na distribuição de sementes é afetada quando se tem pressões de vácuo abaixo de 5 kPa e, consequentemente, maiores consumos. Para semeadura de soja, com as características das sementes como neste trabalho, é recomendando utilizar a pressão de vácuo de 6 kPa. Apresentando esta pressão de vácuo menor consumo de combustível por hora, 11,49 L h¯¹ e área trabalhada, 7,35 L ha¯¹.

Cardiomyocyte oxidants production may signal to T. cruzi intracellular development.

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, presents a variable clinical course, varying from asymptomatic to serious debilitating pathologies with cardiac, digestive or cardio-digestive impairment. Previous studies using two clonal T. cruzi populations, Col1.7G2 (T. cruzi I) and JG (T. cruzi II) demonstrated that there was a differential tissue distribution of these parasites during infection in BALB/c mice, with predominance of JG in the heart. To date little is known about the mechanisms that determine this tissue selection. Upon infection, host cells respond producing several factors, such as reactive oxygen species (ROS), cytokines, among others. Herein and in agreement with previous data from the literature we show that JG presents a higher intracellular multiplication rate when compared to Col1.7G2. We also showed that upon infection cardiomyocytes in culture may increase the production of oxidative species and its levels are higher in cultures infected with JG, which expresses lower levels of antioxidant enzymes. Interestingly, inhibition of oxidative stress severely interferes with the intracellular multiplication rate of JG. Additionally, upon H2O2-treatment increase in intracellular Ca2+ and oxidants were observed only in JG epimastigotes. Data presented herein suggests that JG and Col1.7G2 may sense extracellular oxidants in a distinct manner, which would then interfere differently with their intracellular development in cardiomyocytes.