Evaluation of sample preparation methods and optimization of nickel determination in vegetable tissues

Nickel, although essential to plants, may be toxic to plants and animals. It is mainly assimilated by food ingestion. However, information about the average levels of elements (including Ni) in edible vegetables from different regions is still scarce in Brazil. The objectives of this study were to: (a) evaluate and optimize a method for preparation of vegetable tissue samples for Ni determination; (b) optimize the analytical procedures for determination by Flame Atomic Absorption Spectrometry (FAAS) and by Electrothermal Atomic Absorption (ETAAS) in vegetable samples and (c) determine the Ni concentration in vegetables consumed in the cities of Lorena and Taubaté in the Vale do Paraíba, State of São Paulo, Brazil. By means of the analytical technique for determination by ETAAS or FAAS, the results were validated by the test of analyte addition and recovery. The most viable method tested for quantification of this element was HClO4-HNO3 wet digestion. All samples but carrot tissue collected in Lorena contained Ni levels above the permitted by the Brazilian Ministry of Health. The most disturbing results, requiring more detailed studies, were the Ni concentrations measured in carrot samples from Taubaté, where levels were five times higher than permitted by Brazilian regulations.

Physiological and anatomical characteristics of leaves of two clones of guarana

The objective of this work was to analyze gas exchange, photosynthetic characteristics, photochemical efficiency of photosystem II and anatomical characteristics of young plant leaves of two guarana (Paullinia cupana) clones (BRS-CG372RC and BRS-CG611RL) growing under open field. The variables of gas exchange and fluorescence of chlorophyll a were evaluated in mature leaves. The values of photosynthesis and transpiration found for BRS-CG372RC were 27% greater and 80% lesser than values found for BRS-CG611RL, respectively. The values of stomatal conductance found for the clones BRS-CG372RC and BRS-CG611RL were in the order of 224 and 614 mmol mm-2 s-1, respectively. The values of photorespiration, rate of carboxylation and rate electron transport were greater in BRS-CG372RC. The clone BRS-CG372RC exhibited stomatal density 26% greater than BRS-CG611RL. However, the area of ostiolar opening was 42% greater in BRS-CG611RL. The values of the water use efficiency in BRS-CG372RC were 134% greater than in BRS-CG611RL. High stomatal density and low stomatal conductance can be important characteristics in the selection of the clones with a good ability to assimilate carbon and optimize the use of water.

DETECTION AND QUANTIFICATION OF PHYTOCHEMICAL MARKERS OF Ilex paraguariensis BY LIQUID CHROMATOGRAPHY

Ilex paraguariensis (yerba-mate) is used as a beverage, and its extract requires adequate quality control methods in order to guarantee quality and safe use. Strategies to develop and optimize a chromatographic method to quantify theobromine, caffeine, and chlorogenic acid in I. paraguariensis extracts were evaluated by applying a quality by design (QbD) model and ultra high-performance liquid chromatography (UHPLC). The presence of these three phytochemical markers in the extracts was evaluated using UHPLC-MS and was confirmed by the chromatographic bands in the total ion current traces (m/z of 181.1 [M+H]+, 195.0 [M+H]+, and 353.0 [M−H]−, respectively). The developed method was then transferred to a high-performance liquid chromatography (HPLC) platform, and the three phytochemical markers were used as external standards in the validation of a method for analyses of these compounds in extracts using a diode array detector (DAD). The validated method was applied to quantify the chlorogenic acid, caffeine, and theobromine in the samples. HPLC-DAD chromatographic fingerprinting was also used in a multivariate approach to process the entire data and to separate the I. paraguariensis extracts into two groups. The developed method is very useful for qualifying and quantifying I. paraguariensis extracts.

Effect of harvest at different times of day on the physical and chemical characteristics of vegetable-type soybean

The objective of this study was to evaluate the effect of harvest at different times of day on the chemical and physical characteristics of vegetable-type soybean BRS 267 cultivar, harvested at the R6 stage (seed development) and to compare it with that on the grains harvested at the R8 stage (maturation). The pods of the BRS 267 cultivar were harvested at the R6 stage (at 8:00 AM, 12:00 AM, and 6:00 PM), the color parameters were evaluated, and the grains were analyzed for chemical composition, activity inhibitor trypsin, phytic acid content, starch, sugars, fatty acids, and isoflavones. No differences were observed among the different harvest times in terms of the chemical constituents of vegetable-type soybean BRS 267 cultivar harvested at the R6 stage. Isoflavones content did not change with different harvest times, and the aglycone forms (daidzein, glycitein, and genistein) were found in smaller quantities at the R6 stage compared to the R8 stage. The color of the pods of soybean BRS 267 cultivar, harvested at the R6 stage did not change with different harvest times. The grains harvested at the R6 stage had lower protein content, phytic acid, and sucrose and higher levels of lipids, carbohydrates, starch, glucose, fructose, stachyose, and linolenic acids than those collected at the R8 stage. The different times of harvest did not affect the quality of the vegetable-type soybean BRS 267 cultivar harvested at stage R6. Nevertheless, it is recommended to harvest in the morning, when the temperature is milder, like other vegetables, to facilitate and optimize its marketing and in natura consumption.

Otimização dos parâmetros de produção de hidrolisados protéicos enzimáticos utilizando pescado de baixo valor comercial

The enzymatic modification of proteins has been widely studied with the aim of add value to low commercial value fish. The objective of this work was to evaluate and optimize the parameters involved in the production process of an enzymatic protein hydrolyzed with high protein content. The results showed that for Alcalase the most significant parameters were temperature, pH and substrate concentration and for Flavourzyme were pH, substrate concentration and enzyme concentration. It was obtained for Alcalase a predictive model for the recovered nitrogen and for Flavourzyme a predictive model for the hydrolysis degree.

Determinação de fósforo biodisponível em rações de peixes utilizando extração assistida por ultra-som e espectrofotometria no visível

The aim of the present work was to develop and optimize a method for determination of bioavailable phosphorus in samples of feces and fish feed using ultrasound extraction and subsequent quantification by visible spectrophotometry. Using as extractor solution HNO3 0.50 mol L-1, the great conditions of extraction established were: sample mass - 100 mg, samples granulometry - < 60 µm, sonification time - five cycles of 40 s and ultrasound potency - 136 W. The proposed method was applied in studies of digestibility of this nutrient in different feeds used in diets of juvenile of Nile tilapia.

Role of Notch signaling in the mammalian heart

Notch signaling is an evolutionarily ancient, highly conserved pathway important for deciding cell fate, cellular development, differentiation, proliferation, apoptosis, adhesion, and epithelial-to-mesenchymal transition. Notch signaling is also critical in mammalian cardiogenesis, as mutations in this signaling pathway are linked to human congenital heart disease. Furthermore, Notch signaling can repair myocardial injury by promoting myocardial regeneration, protecting ischemic myocardium, inducing angiogenesis, and negatively regulating cardiac fibroblast-myofibroblast transformation. This review provides an update on the known roles of Notch signaling in the mammalian heart. The goal is to assist in developing strategies to influence Notch signaling and optimize myocardial injury repair.

Optimization of the extraction process of polyphenols from cashew apple agro-industrial residues

The goal of this study was to determine the chemical composition of cashew apples agro-industrial residue and optimize the process of polyphenols extraction in this residue. The extraction process conditions were defined using a 24-1 fractional factorial experimental design using acetone and methanol as solvents. The independent variables were: time (30 to 90 min), temperature (30 to 50 °C), solvent concentrations (50% to 90%), agitation speed (100 to 300 rpm); the dependent variables were: total phenolic content and DPPH scavenging capacity. The optimized process was carried out by applying the Central Composite Rotational Design (CCRD) considering the results obtained with the 24-1 fractional factorial experimental design. The residue presented bioactive compounds in its composition, with emphasis on the content of total phenolic compounds (1975.64 mg/ 100 g). The extraction process was not affected by methanol; however, acetone affected the amounts of extracted phytochemicals. Extracts with high levels of polyphenols and strong DPPH scavenging capacity (> 80%) were obtained using 55% acetone, 30 minutes, 30 °C, and 150 rpm. The results showed that cashew apple residue is a potential natural source of bioactive compounds with strong antioxidant capacity. These compounds could be used partially or totally to replace synthetic antioxidants.

Leaf area and epicuticular wax content of Sida spp

Morpho-physiological characteristics and chemical composition are directly related to superior competitive ability of crops. This study intended to make a comparative analysis of dry matter production, leaf area and amount of epicuticular wax of three species of Sida spp: S. urens L., S. rhombifolia L. and S. spinosa L. Plants were collected at three growth stages: V1: stage described as up to 10 fully expanded leaves; V2: between 11 leaves and flowering; and R: after flowering. At stages V2 and R, the highest number of leaves was recorded for S. rhombifolia, followed by S. spinosa at V2 and S. urens at R. These results were relatively proportional to leaf area for all species. S. spinosa at the vegetative stage produced the highest values of specific leaf area (SLA), with no significant differences between species at the stage R. The amount of wax per unit of leaf area between species at the same developmental stage was significantly different only at the reproductive stage, where S. spinosa produced 23.18 and 6.23 fold more wax than S. urens and S. rhombifolia respectively. Between the growth stages of each species, there was decrease in the amount of wax with plant age and increase in leaf area (AFE), number of leaves and dry matter. The leaves of the Sida species exhibit different characteristics and this information can be used to optimize the use of herbicides in the control of these weeds.

The phosphate fixing capacities of two soils from the Piracicaba municipality: latosol and sands

An essay was carried out under laboratory conditions in order to know the phosphate fixing capcity of a Latosol and a Sands from the municipality of Piracicaba, State of São Paulo, Brazil. The results showed that they were able to fix about 1,588 and 274 kg/ha of P2O5> respectively.

Use of camera-traps in natural trails and shelters for the mammalian survey in the Atlantic Forest

In order to evaluate the efficiency of different mammalian survey methods, we compared traditional sampling techniques (use of camera-traps on roads and artificial trails, track censuses, and direct field visualization) with an alternative sampling design (camera-traps positioned in natural areas such as natural trails and shelters). We conducted the study in a deciduous Atlantic-Forest park in southern Brazil, and additionally compared our results with a previous intensive study carried out in the same area. Our considerably smaller sampling effort (example: 336 trap.day for our camera-traps versus 2,154 trap.day for the earlier study) registered the presence of 85% of the local known species, with camera-traps being 68% efficient. Moreover, shelter camera-traps revealed a different species composition regarding most of other sampling methods. This sampling strategy involving natural forest sites was therefore able to effectively optimize the chances of evaluating species composition in a shorter period, especially with respect to lower-density and cryptic species, as well as to detect species that avoid open, disturbed sites such as roads and man-made forest trails.

Environmental determinants of infectious and parasitic diseases

A review of the role of the environment as a determinant of infectious and parasitic diseases is presented. Historical considerations and the several environmental classifications of diseases are introduced. In a broader perspective the subject is analyzed in view of the emergence of the environmental health area, with its new paradigms. A review of epidemiological studies about environmental sanitation conditions and measures is presented, analyzing the conclusions derived from 256 studies. Finally, an epidemiological study carried out in Betim, Minas Gerais is briefly described, in order to illustrate the potentiality of this kind of study. Setting priorities of interventions regarding diarrhea control was the aim of this investigation. Conclusion about the role of this approach to optimize preventive measures for the control of infectious and parasitic diseases, of sound importance to the reality of the developing world, is stated.

Redescription of Anopheles (Nyssorhynchus) antunesi Galvão & Amaral and description of a new species of the Myzorhynchella Section (Diptera: Culicidae) from Serra da Mantiqueira, Brazil

Anopheles (Nyssorhynchus) pristinus Nagaki & Sallum, n. sp. of the Myzorhynchella Section is described based on morphological characters of adult females, males, fourth-instar larvae, pupae and male genitalia. Anopheles (Nyssorhynchus) antunesi Galvão & Amaral is characterized to fix its identity and distinguish it from An. pristinus. The eggs of An. antunesi are described for the first time. Molecular characterization employing sequences of the COI mitochondrial gene and the ITS2 region of ribosomal DNA are provided for each species. An. antunesi and An. pristinus are compared with morphologically similar species of the Myzorhynchella Section. The results of the present study suggest that the new species has been misidentified as both An. antunesi and Anopheles lutzii Cruz. An. antunesi and An. pristinus are sympatric, occurring at high altitudes in Serra da Mantiqueira, Southeastern Brazil.

Soil, water and nutrient losses by interrill erosion from green cane cultivation

Interrill erosion occurs by the particle breakdown caused by raindrop impact, by particle transport in surface runoff, by dragging and suspension of particles disaggregated from the soil surface, thus removing organic matter and nutrients that are essential for agricultural production. Crop residues on the soil surface modify the characteristics of the runoff generated by rainfall and the consequent particle breakdown and sediment transport resulting from erosion. The objective of this study was to determine the minimum amount of mulch that must be maintained on the soil surface of a sugarcane plantation to reduce the soil, water and nutrient losses by decreasing interrill erosion. The study was conducted in Pradópolis, São Paulo State, in 0.5 x 1.0 m plots of an Oxisol, testing five treatments in four replications. The application rates were based on the crop residue production of the area of 1.4 kg m-2 (T1- no cane trash; T2-25 % of the cane trash; T3- 50 % trash; T4-75 % trash; T5-100 % sugarcane residues on the surface), and simulated rainfall was applied at an intensity of 65 mm h-1 for 60 min. Runoff samples were collected in plastic containers and soon after taken to the laboratory to quantify the losses of soil, water and nutrients. To minimize soil loss by interrill erosion, 75 % of the cane mulch must be maintained on the soil, to control water loss 50 % must be maintained and 25 % trash controls organic matter and nutrient losses. This information can contribute to optimize the use of this resource for soil conservation on the one hand and the production of clean energy in sugar and alcohol industries on the other.

Nitrogen symbiotically fixed by cowpea and gliricidia in traditional and agroforestry systems under semiarid conditions

The objective of this work was to estimate the amounts of N fixed by cowpea in a traditional system and by cowpea and gliricidia in an agroforestry system in the Brazilian Northeast semiarid. The experiment was carried out in a randomized complete block design, in a split-plot arrangement, with four replicates, in the semiarid region of the state of Paraíba, Brazil. Plots consisted of agroforestry and traditional systems (no trees), and split-plots of the three crops planted between the tree rows in the agroforestry system. To estimate N fixation, plant samples were collected in the fourth growth cycle of the perennial species and in the fourth planting cycle of the annual species. In the agroforestry system with buffel grass and prickly-pear cactus, gliricidia plants symbiotically fix high proportions of N (>50%) and contribute with higher N amounts (40 kg ha-1 in leaves) than in the traditional system (11 kg ha-1 in grain and 18 kg ha-1 in straw). In the agroforestry system with maize and cowpea, gliricidia plants do not fix nitrogen, and N input is limited to the fixation by cowpea (2.7 kg ha-1), which is lower than in the traditional system due to its lower biomass production.