Solubilization of CaHPO4 and AlPO4 by Aspergillus niger in culture media with different carbon and nitrogen sources

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Carbon, nitrogen and phosphorus mineralization in two soils amended with distillery yeast

The possibility of using yeast from alcohol distilleries as a source of nutrients in soil was investigated. The following treatments were used: no fertilization (control), 0.5% (w/w) yeast, 1% (w/w) yeast, and NPK. The decomposition of yeast was monitored for 90 days in two soils. The CO, production and the microbial biomass were increased by art average of 1- to 3-fold by yeast incorporation compared to control. Protease activity also was enhanced 3- to 8-fold in the soils supplemented with yeast compared to control. The phosphatase activities were higher than control only during the first days. While nitrate contents increased in all treatments compared to control, available P only increased in the soils amended with 1%, yeast or NPK by 45-119% and 309-489%, respectively. These results indicate that there exists an excellent potential for the use of yeast in the soil as a source of nitrate and available P for plant nutrition. (C) 2003 Elsevier Ltd. All rights reserved.

Production of polysaccharidases in different carbon sources by Leucoagaricus gongylophorus Moller (Singer), the symbiotic fungus of the leaf-cutting ant Atta sexdens linnaeus

Leucoagaricus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens, produces polysaccharidases that degrade leaf components by generating nutrients believed to be essential for ant nutrition. We evaluated pectinase, amylase, xylanase, and cellulase production by L. gongylophorus in laboratory cultures and found that polysaccharidases are produced during fungal growth on pectin, starch, cellulose, xylan, or glucose but not cellulase, whose production is inhibited during fungal growth on xylan. Pectin was the carbon source that best stimulated the production of enzymes, which showed that pectinase had the highest production activity of all of the carbon sources tested, indicating that the presence of pectin and the production of pectinase are key features for symbiotic nutrition on plant material. During growth on starch and cellulose, polysaccharidase production level was intermediate, although during growth on xylan and glucose, enzyme production was very low. We propose a possible profile of polysaccharide degradation inside the nest, where the fungus is cultured on the foliar substrate.

Screening Botryosphaeria species for lipases: Production of lipase by Botryosphaeria ribis EC-01 grown on soybean oil and other carbon sources

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Stable isotopes for determining carbon turnover in sheep feces and blood

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photodegradation of lincomycin and diazepam in sewage treatment plant effluent by photo-Fenton process

First, the effect of ferrioxalate or iron nitrate on the photo-Fenton degradation efficiency of the pharmaceuticals lincomycin (LCM) and diazepam (DZP) was evaluated. The degradation of both pharmaceuticals was improved in the presence of ferrioxalate in relation to Fe(NO(3)), either under black-light or solar irradiation. The degradation of the pharmaceuticals was then evaluated when present in an effluent from sewage treatment plant (STP) under black-light irradiation. Pharmaceuticals oxidation was not influenced by the matrix, since very similar results were obtained when compared to the experiments carried out in distilled water. However, DOC removal was slightly affected by the matrix, due probably to the generation of recalcitrant intermediates during effluent photodegradation and to the high content of inorganic carbon of STP effluent. Even so, high DOC removal percentages were achieved, 65% for lincomycin and 80% for diazepam after 60 min irradiation. (C) 2010 Elsevier B.V. All rights reserved.

Phosphorus, nitrogen, and carbon contents of macrophytes in lakes lateral to a tropical river (Paranapanema River, São Paulo, Brazil)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electrochemical reduction and determination of Cibacron Blue F3GA at poly-L-lysine modified glassy carbon electrode

The oxidation of a reactive dye, Cibacron Blue F3GA, CB, (C.I. 61211), widely used in the textile industries to color natural fibers, was studied by electrochemical techniques. The oxidation on glassy carbon electrode occurs in two steps at 2.0 < pH < 10 involving one electron transfer each to the amine group leading to the imide derivative. Stable films of poly-L-lysine (PLL) in the presence of glutaraldehyde (GA) 97.5%:2.5% on glassy carbon electrode can be used to detect low levels of dye using its oxidation peak at +0.75V by voltammetry. Linear calibration graphs were obtained for the CB reactive dye, from 1.0 X 10(-6) to 1.0 X 10(-5) mol L-1 in B-R buffer, pH 2.0, using a pre-concentration off-line during 10 min. The detection limit (3 sigma/slope) was calculated to be 4.5 X 10(-8) mol L-1. Films of PLL can readily be applied for the determination of CB dye bearing aminoanthraquinone as chromophore and chlorotriazinyl as reactive group at concentrations at least 100 times lesser than using a glassy carbon electrode without modification. The method described was applied for the determination of CB dye in tap water and raw water collected from the municipal treatment plant with a recovery of 89.2% +/- 5.4 and 88.0% +/- 6.5, respectively. (c) 2005 Elsevier Ltd. All rights reserved.

PALEOCLIMATIC CONTROLS ON STABLE OXYGEN AND CARBON ISOTOPES IN CALICHE OF THE ABO FORMATION (PERMIAN), SOUTH-CENTRAL NEW-MEXICO, USA

The stable oxygen and carbon isotopic composition of caliche in fluvial and supratidal rocks of the Abo Formation (Permian), south-central New Mexico, is controlled by palecoclimate and depositional environment. Fluvial caliche consists of low-Mg calcite nodules and vertically oriented tubules that display stage II texture. Micrite matrix support, brecciation, ooids/pisoliths, aveolar-septal texture, and peloids are common in the fluvial caliche and, along with red color and slickensides in the host shale, indicate pedogenesis in a well-oxidized vadose zone. In contrast, periodic waterlogging of the supratidal paleosols, probably due to high water table, is indicated by drab colors, carbonaceous flecks, horizontal rhizoliths, and the paucity of vadose textures in the stage II caliche nodules.Stable oxygen isotopes are similar in the fluvial and supratidal caliches and range from 21.6 to 30.5 parts per thousand (SMOW). The data exhibit a crude bimodality and delta-O-18 enrichment with a decrease in age (higher in the section). Consideration of these data in the context of delta-temperature relations suggests that 1) surface waters responsible for caliche formation increased in delta-O-18 (from roughly -8 to + 1 parts per thousand) over the 18 m.y. time interval that separated the lowest stratigraphic nodule horizon from the highest, 2) the increasing delta-O-18 values also reflect a warming trend (approximately 15-degrees to nearly 30-degrees-C) in the mean monthly temperature over this same time period, with perhaps an associated increase in Permian ocean temperatures, and 3) the significant variation in delta-O-18 from oldest to youngest caliche was probably enhanced by the amount effect, such that as the temperature increased, the amount of precipitation decreased, resulting in high delta-O-18 values.Caliches in the Abo are enriched in heavy carbon (-7.2 to -1.5 part per thousand PDB) compared to that of soil carbonate derived exclusively from C3 plants (-12 part per thousand PDB), and the supratidal caliches contain somewhat heavier carbon compared to the fluvial caliche. The delta-C-13 values for both environments increase with a decrease in caliche age. These results indicate that as the temperature increased and rainfall decreased with time, the level of C3 plant productivity apparently declined, allowing a greater influx of atmospheric CO2 into the soil. This can only occur when soil respiration rates are quite low or at very shallow depths (less than 10 cm), or both. Atmospheric CO2 seems to have invaded the supratidal soils to a somewhat greater extent than the fluvial soils.

Nitrous oxide production and potential denitrification in soils from riparian buffer strips: Influence of earthworms and plant litter

Vegetated riparian buffer strips have been established in Southern Quebec (Canada) in order to intercept nutrients such as nitrate (NO(3)(-)) and protect water quality near agricultural fields. Buffer strips may also favour denitrification through a combination of high soil moisture, NO(3)(-) and carbon supply, which could lead to the production of nitrous oxide (N(2)O), a greenhouse gas. Denitrification could be further amplified by the presence of earthworms, or by plant species that promote earthworm and bacterial activity in soils. Soils from four farms, comprising maize fields and adjacent buffer strips, were sampled in the fall of 2008. A total of six earthworm species were found, but average earthworm biomass did not differ between buffer strips and maize agroecoecosystems. Nitrate concentrations and net nitrification rates were higher in the maize fields than in the buffer strips: there was no difference in N(2)O production in soils collected from the two sampling locations. Potential denitrification, measured by acetylene inhibition, varied by two orders of magnitude, depending on experimental conditions: when amended with H(2)O or with H(2)O + NO3-, potential denitrification was higher (P < 0.05) in soils from buffer strips than from maize fields. Potential denitrification was highest in soils amended with H(2)O+glucose, or with H(2)O+ NO(3)(-) + glucose. Using microcosms, we tested the effect of litter-soil mixtures on earthworm growth, and the effect of earthworm-litter-soil mixtures on potential denitrification. Based on four categories of chemical assays, litters of woody species (oak, apple, Rhododendron) were generally of lower nutritional quality than litter from agronomic species (alfalfa, switchgrass, corn stover). Alfalfa litter had the most positive effect, whereas apple litter had the most negative effect, on earthworm growth. Potential denitrification was 2-4 times higher in earthworm-litter-soil mixtures than in plain soil. Litter treatments that included corn stover had lower potential denitrification than those that included alfalfa or switchgrass, whereas litter treatments that included oak had lower potential denitrification than those that included apple or Rhododendron. Results suggest that potential N(2)O emissions may be higher in riparian buffer strips than in adjacent maize fields, that N(2)O emissions in buffer strips may be amplified by comminuting earthworms, and that plant litters that reduce earthworm growth may not be best at mitigating N(2)O emissions. (c) 2010 Elsevier B.V. All rights reserved.

Carbon isotope composition and leaf anatomy as a tool to characterize the photosynthetic mechanism of Artemisia annua L.

Leaves of Artemisia annua L. are a plentiful source of artemisinin, a drug with proven effectiveness against malaria. The aim of this study was to classify the photosynthetic mechanism of A. annua through studies of the carbon isotope composition (δ 13C) and the leaf anatomy. A. annua presented a δ 13C value of - 31.76 ± 0.07, which characterizes the plants as a typical species of the C3 photosynthethic mechanism, considering that the average δ 13C values for C3 and C4 species are -28 and -14, respectively. The leaf anatomy studies were consistent with the δ 13C results, where, in spite of the existence of parenchymatic cells forming a sheath surrounding the vascular tissue, the cells do not contain chloroplasts or starch. This characteristic is clearly different from that of the Kranz anatomy found in C4 species.

Fatty acid production by four strains of Mucor hiemalis grown in plant oil and soluble carbohydrates

Four Mucor hiemalis strains (M1, M2, M3 and M4), isolated from soil at a depth of 0 - 15 cm in the Juréia-Itatins Ecology Station (JIES), in the state of São Paulo, Brazil and were evaluated for the production of γ-linolenic (GLA) and other unsaturated fatty acids. Five growth variables (temperature, pH, carbon source, nitrogen source, and vegetable oils) were studied. Liquid media containing 2% vegetable oil (palm oil, canola oil, soybean oil, sesame oil, or sunflower oil) or 2% carbohydrate (fructose, galactose, glycerol, glucose, lactose, maltose, sucrose, sorbitol or xylose) and 1% yeast extract as a nitrogen source were used. The greatest biomass production was observed with M3 and M4 strains in palm oil (91.5 g l -1) and sunflower oil (68.3 g l -1) media, respectively. Strain M4 produced greater quantities of polyunsaturated acids in medium containing glucose. The GLA production in the M4 biomass was 1,132.2 mg l -1 in glucose medium. Plant oils were inhibitors of fatty acid production by these strains. © 2007 Academic Journals.

The use of the carbon-13 in the partitioning of photosynthate in vegetative and reproductive twigs of 'Sweet' passion fruit

This study's objective is to evaluate the photosynthates partitioning and source-sink relationships, in vegetative and reproductive twigs of sweet passion fruit, using the carbon-13, stable isotope of carbon. The leaves of vegetative and reproductive twigs were placed in a sealed chamber and 13CO 2 were injected for 30 minutes. After six hours, the different organs of the twig were collected and immersed in liquid nitrogen (-196°C). All plant samples were oven-dried, powdered and combusted in an elemental analyzer. The results showed that the methodology was efficient to evaluate the partitioning of photosynthates. In the vegetative twigs, the new open leaves, the closed leaves and growth meristem were the principal sink for the source leaves enriched with 13CO 2. In the reproductive twigs with only flowers buds, the source-sink relationship was changed and the flowers buds turn to be the principal sink and the growing leaves were secondary sinks. The presence of young fruits changed again the source-sink relationship of the twig, and they were the principal sinks. The apical leaves, with 60% of final leaf area were also a sink for photosynthates.

Carbon dioxide emissions under different soil tillage systems in mechanically harvested sugarcane

Soil tillage and other methods of soil management may influence CO 2 emissions because they accelerate the mineralization of organic carbon in the soil. This study aimed to quantify the CO2 emissions under conventional tillage (CT), minimum tillage (MT) and reduced tillage (RT) during the renovation of sugarcane fields in southern Brazil. The experiment was performed on an Oxisol in the sugarcane-planting area with mechanical harvesting. An undisturbed or no-till (NT) plot was left as a control treatment. The CO2 emissions results indicated a significant interaction (p < 0.001) between tillage method and time after tillage. By quantifying the accumulated emissions over the 44 days after soil tillage, we observed that tillage-induced emissions were higher after the CT system than the RT and MT systems, reaching 350.09 g m-2 of CO2 in CT, and 51.7 and 5.5 g m-2 of CO2 in RT and MT respectively. The amount of C lost in the form of CO2 due to soil tillage practices was significant and comparable to the estimated value of potential annual C accumulation resulting from changes in the harvesting system in Brazil from burning of plant residues to the adoption of green cane harvesting. The CO 2 emissions in the CT system could respond to a loss of 80% of the potential soil C accumulated over one year as result of the adoption of mechanized sugarcane harvesting. Meanwhile, soil tillage during the renewal of the sugar plantation using RT and MT methods would result in low impact, with losses of 12% and 2% of the C that could potentially be accumulated during a one year period. © 2013 IOP Publishing Ltd.

Non-labile plant C contributes to long-lasting macroaggregation of an Oxisol

Decomposition of plant material influences soil aggregation dynamics in ways that are still poorly understood, especially for Oxisols, in which oxides are believed to play a dominant role. In an incubation experiment, we investigated (i) the effect of plant material addition from selected monocot and dicot species on soil organic C (SOC), carbohydrate composition, fungal and total microbial biomass, and aggregation of an Oxisol; and (ii) the relationship among these properties and C mineralization patterns. The experiment was carried out at 25 °C for 180 d after addition of 11 plant materials (4 g C kg-1 soil) and a control (no plant material added). Mineralization of C during the incubation was described considering two pools of C (labile and non-labile) using a first-order plus linear fitting. Compared to the control, corn materials showed larger pentose input, greater mineralization rates for the non-labile C pool (k), greater soil pentose content (xylose + arabinose) and larger mean weight diameter of soil water-stable aggregates at 180 d of incubation. These effects were independent of changes in SOC content, suggesting that total C accrual and macroaggregation may be decoupled processes in this Oxisol. Our results support the hypothesis that the non-labile plant C pool contributes to the long-lasting stability of macroaggregates of this Oxisol and that this effect is mediated by plant and soil pentoses. We propose that plant pentose content and the decomposition rate of the slow pool (k) are useful parameters for the prediction of plant effects on aggregation dynamics of Oxisols and the selection of soil conservation practices. © 2012.