Changes in a Rhodic Hapludox under no-tillage and urban waste compost in the northwest of Rio Grande do Sul, Brazil

The use of urban waste compost as nutrient source in agriculture has been a subject of investigation in Brazil and elsewhere, although the effects on soil physical and chemical properties and processes are still poorly known. The aim of this study was to evaluate the effect of application of urban waste compost and mineral fertilizer on soil aggregate stability and organic carbon and total nitrogen content of a Rhodic Hapludox under no-tillage in the northwestern region of Rio Grande do Sul, Brazil, in the 2009/2010 and 2010/2011 growing seasons. The experiment was arranged in a 2 × 6 (seasons and fertilization) factorial in a randomized complete block design with four replications. The factor time consisted of two growing seasons (sunflower in 2009/10 and maize in 2010/11) and the factor fertilization of five rates of urban waste compost (0, 25, 50, 75 and 100 m³ ha-1), and mineral fertilizer. Soil samples were collected from the 0.0-0.10 m layer to determine aggregate stability (mean weight and geometric diameter), soil organic carbon (SOC) and total nitrogen (TN). Rates of up to 75 m³ ha-1 of urban waste compost, after two years of application to no-tillage maize and sunflower, improved aggregation compared to mineral fertilization in a Rhodic Hapludox. After the second crop, the SOC and TN contents increased linearly with the levels of urban waste compost.

Agrobacterium-mediated genetic transformation of 'Hamlin' sweet orange

The development and optimization of efficient transformation protocols is essential in new citrus breeding programs, not only for rootstock, but also for scion improvement. Transgenic 'Hamlin' sweet orange (Citrus sinensis (L.) Osbeck) plants were obtained by Agrobacterium tumefaciens-mediated transformation of epicotyl segments collected from seedlings germinated in vitro. Factors influencing genetic transformation efficiency were evaluated including seedling incubation conditions, time of inoculation with Agrobacterium and co-culture conditions. Epicotyl segments were adequate explants for transformation, regenerating plants by direct organogenesis. Higher percentage of transformation was obtained with explants collected from seedlings germinated in darkness, transferred to 16 hours photoperiod for 2-3 weeks, and inoculated with Agrobacterium for 15-45 min. The best co-culture condition was the incubation of the explants in darkness, for three days in culture medium supplemented with 100 muM of acetosyringone. Genetic transformation was confirmed by performing beta-glucoronidase (GUS) assays and, subsequently, by PCR amplification for the nptII and GUS genes.

Optimization of particle bombardment parameters for the genetic transformation of Brazilian maize inbred lines

The objective of this work was to develop a genetic transformation system for tropical maize genotypes via particle bombardment of immature zygotic embryos. Particle bombardment was carried out using a genetic construct with bar and uidA genes under control of CaMV35S promoter. The best conditions to transform maize tropical inbred lines L3 and L1345 were obtained when immature embryos were cultivated, prior to the bombardment, in higher osmolarity during 4 hours and bombarded at an acceleration helium gas pressure of 1,100 psi, two shots per plate, and a microcarrier flying distance of 6.6 cm. Transformation frequencies obtained using these conditions ranged from 0.9 to 2.31%. Integration of foreign genes into the genome of maize plants was confirmed by Southern blot analysis as well as bar and uidA gene expressions. The maize genetic transformation protocol developed in this work will possibly improve the efficiency to produce new transgenic tropical maize lines expressing desirable agronomic characteristics.

Biodiversity of Collembola in urban soils and their use as bioindicators for pollution

The objective of this work was to evaluate the effects of pollutants on the abundance and diversity of Collembola in urban soils. The research was carried out in three parks (Cişmigiu, Izvor and Unirea) in downtown Bucharest, where the intense car traffic accounts for 70% of the local air pollution. One site in particular (Cişmigiu park) was highly contaminated with Pb, Cd, Zn and Cu at about ten times the background levels of Pb. Collembola were sampled in 2006 (July, September, November) using the transect method: 2,475 individuals from 34 species of Collembola were collected from 210 samples of soil and litter. Numerical densities differed significantly between the studied sites.The influence of air pollutants on the springtail fauna was visible at the species richness diversity and soil pollution levels. Species richness was lowest in the most contaminated site (Cismigiu, 11 species), which presented an increase in springtails abundances, though. Some species may become resistant to pollution and occur in high numbers of individuals in polluted sites, which makes them a good bioindicator of pollutants.

The effects of polycyclic aromatic hydrocarbons and heavy metals on terrestrial annelids in urban soils

The effect of soil contamination by polycyclic aromatic hydrocarbons (PAH) and heavy metals on earthworms and enchytraeids was studied in urban parks, in Brno, Czech Republic. In spring and autumn 2007, annelids were collected and soil samples taken in lawns along transects, at three different distances (1, 5 and 30 m) from streets with heavy traffic. In both seasons, two parks with two transects each were sampled. Earthworms were collected using the electrical octet method. Enchytraeids were extracted by the wet funnel method from soil cores. All collected annelids were counted and identified. Basic chemical parameters and concentrations of 16 PAH, Cd, Cu, Pb, and Zn were analysed from soil from each sampling point. PAH concentrations were rather low, decreasing with the distance from the street in spring but not in autumn. Heavy metal concentrations did not decrease significantly with increasing distance. Annelid densities did not significantly differ between distances, although there was a trend of increase in the number of earthworms with increasing distance. There were no significant correlations between soil content of PAH or heavy metals and earthworm or enchytraeid densities. Earthworm density and biomass were negatively correlated with soil pH; and enchytraeid density was positively correlated with soil phosphorus.

Induction of transgenic hairy roots in soybean genotypes by Agrobacterium rhizogenes‑mediated transformation

The objective of this work was to perform the screening of soybean genotypes as to their ability to respond to the induction of hairy roots by Agrobacterium rhizogenes‑mediated transformation. Four Brazilian soybean cultivars (BRSMG 68 Vencedora, BRS 137, Embrapa 48, and MG/BR 46 Conquista) and two North American ones adapted to Brazilian cropping conditions (Bragg and IAS‑5) were screened for their capacity to respond to A. rhizogenes in protocols for in vitro hairy root culture and ex vitro composite plant production. Four‑day‑old seedlings with uniform size were injected with A. rhizogenes harboring the plasmid p35S‑GFP. Seedlings expressing green fluorescent protein (GFP) in at least one hairy root were used to determine the transformation frequency. Using an axenic in vitro protocol, excised cotyledons from four‑day‑old seedlings were infected with A. rhizogenes harboring the pCAMBIA1301 plasmid, containing the gusA reporter gene. The transformation frequency and the number of days for hairy root emergence after bacterial infection (DAI) were evaluated. The transformation frequency and DAI varied according to the genotype. Cultivars MG/BR 46 Conquista and BRSMG 68 Vencedora are more susceptible to A. rhizogenes and can be recommended for transformation experiments.

Watermelon transformation with Zucchini yellow mosaic virus coat protein gene and comparison with parental cultivar

The objective of this work was to transfer Zucchini yellow mosaic virus coat protein (ZYMV-CP) and neomycin phosphotransferase II (NPT II) genes to the watermelon 'Crimson Sweet'(CS) genome, and to compare the transgenic progenies T1 and T2 with the nontransformed parental cultivar for morphological, pomological, growth and yield characteristics. The ZYMV-CP gene was transferred by Agrobacterium tumefaciens. The presence of the gene in transgenic T0, T1 and T2 plants was determined by polymerase chain reaction, and the results were confirmed by Southern blot. Two experiments were performed, one in the winter-spring and the other in the summer-autumn. In both experiments, the hypocotyl length of transgenic seedlings was significantly higher than that of nontransgenic parental ones. In the second experiment, the differences between transgenic and nontransgenic individuals were significant concerning fruit rind thickness, flesh firmness, fruit peduncle length, size of pistil scar, and a* values for fruit stripe or flesh color. Transferring ZYMV-CP gene to CS genome affected only a few characteristics from the 80 evaluated ones. The changes in rind thickness, flesh firmness and flesh color a* values are favorable, while the increase in the size of pistil scar is undesirable. The transgenic watermelon line having ZYMV-CP gene and the parental cultivar CS are very similar.

Genetic transformation of sweet oranges with the D4E1 gene driven by the AtPP2 promoter

The objective of this work was to produce transgenic 'Pêra' and 'Valência' sweet orange plants using the D4E1 gene driven by the Arabidopsis thaliana phloem protein (AtPP2) promoter and to quantify transgene expression in different transformation events. Genetic transformation experiments were carried out with epicotyl segments co‑cultivated with Agrobacterium tumefaciens. Six plants from 'Pêra' sweet orange and seven plants from 'Valência' sweet orange were confirmed as different transgenic events by means of the polymerase chain reaction (PCR) and the Southern blot techniques. Transgene expression was quantified using real‑time quantitative PCR. D4E1 gene expression levels vary from 5 up to 50 times among different transformation events.

Aerosol particle size distributions at a traffic exposed site and an urban background location in Oporto, Portugal

Aerosol size distributions from 6 to 700 nm were measured simultaneously at an urban background site and a roadside station in Oporto. The particle number concentration was higher at the traffic exposed site, where up to 90% of the size spectrum was dominated by the nucleation mode. Larger aerosol mode diameters were observed in the urban background site possibly due to the coagulation processes or uptake of gases during transport. Factor analysis has shown that road traffic and the neighbour stationary sources localised upwind affect the urban area thought intra-regional pollutant transport.

Nitrous oxide emissions from an intermittent aeration activated sludge system of an urban wastewater treatment plant

This study investigated the emission of N2O during the sequential aerated (60-min) and non-aerated (30-min) stages of an intermittent aeration cycle in an activated sludge wastewater treatment plant (WWTP). N2O emission occurred during both stages; however, emission was much higher during aeration. Air stripping is the major factor controlling transfer of N2O from the sewage to the atmosphere. The N2O emissions exclusively from the aeration tank represented 0.10% of the influent total nitrogen load and the per capita emission factor was almost 3 times higher than that suggested by the IPCC for inventories of N2O emission from WWTPs.

Inhalable particulate matter characterization in a medium-sized urban region in Brazil (São José dos Campos Town) - Part I: Morphology

In this study, the concentration and morphological characteristics of inhalable particulate material (PM10) were evaluated and associated with climatic conditions. The mean annual concentration was 11.0 µg m−3, varying between 0,647 µg m−3 and 36.8 µg m−3. Wind speed has a higher influence on PM10 dispersion, but direction was associated with particle source. During the wet period, wind speed is the main dispersion factor, while speed and direction both are important during the dry period. Based on the morphological characteristics, it is concluded that biogenic particles prevail during the rainy season and terrigenous particles during the dry period, depending on the wind direction and intensity.

ACIDITY OF MODIFIED MORDENITES SYNTHESIZED FROM RICE HUSK SILICA AND CATALYTIC TRANSFORMATION OF METHYLBUTYNOL

Mordenite (MOR) was synthesized using rice husk silica and modified by base (B), acid (A) or acid-base (AB) and converted to H-form. The modification did not destroy the MOR structure but increased surface area and generated mesopores. Lewis acidity of the parent and modified MOR samples investigated by aluminum NMR and NH3-TPD showed a decrease in the following order: HMOR > BMOR > ABMOR > AMOR. For the catalytic transformation of methylbutynol, ABMOR provided the highest conversion and selectivity of products from acid sites.

Transformation of Xanthomonas axonopodis pv. citri by electroporation

This study describes the use of electroporation for transforming Xanthomonas axonopodis pv. citri (Xac), the causal agent of citrus (Citrus spp.) canker. It also evaluates the methodology used for this species under different electrical parameters. The bacterium used in the study (Xac 306) was the same strain used for recent complete sequencing of the organism. The use of a plasmid (pUFR047, gentamycin r) is reported here to be able to replicate in cells of Xac. Following the preparation and resuspension of competent cells of Xac at a density of ~4 x 10(10) cfu/ml, in 10% glycerol, and the addition of the replicative plasmid, an electrical pulse was applied to each treatment. Selection of transformants showed a high efficiency of transformation (1.1 x 10(6) transformants/mug DNA), which indicates an effective, and inverse, combination between electrical resistance (50 W) and capacitance (50 µF) for this species, with an electrical field strength of 12.5 kV.cm-1 and 2.7-ms pulse duration. Besides the description of a method for electroporation of Xac 306, this study provides additional information for the use of the technique on studies for production of mutants of this species.

Evaluation of the dioxin and furan formation thermodynamics in combustion processes of urban solid wastes

Specific combustion programs (Gaseq, Chemical equilibria in perfect gases, Chris Morley) are used to model dioxin and formation in the incineration processes of urban solid wastes. Thanks to these programs, it is possible to establish correlations with the formation mechanisms postulated in literature on the subject. It was found that minimum oxygen quantities are required to obtain a significant formation of these compounds and that more furans than dioxins are formed. Likewise, dioxin and furan formation is related to the presence of carbon monoxide, and dioxin and furan distribution among its different compounds depends on the chlorine and hydrogen relative composition. This is due to the fact that an increased chlorine availability leads to the formation of compounds bearing a higher chlorine concentration (penta-, hexa-, hepta-, and octachlorides), whereas an increased hydrogen availability leads to the formation of compounds bearing a lower chlorine number (mono, di-, tri-, and tetrachlorides).

Di-And Tri-Hydroxylated Kaurane Derivatives From Microbial Transformation Of Ent-Kaur-16-En-19-Ol By Cephalosporium Aphidicola And Their Allelopathic Activity On Lactuca Sativa (Lettuce)

The use of microorganisms to induce chemical modifications in organic molecules is a very useful tool in organic synthesis, to obtain biologically active substances. The fungus Cephalosporium aphidicola is known by its ability to hydroxylate several skeleton positions of many classes of organic compounds. In this work, the microbial transformation of ent-kaur-16-en-19-ol (1) by C. aphidicola, afforded two hydroxylated compounds, ent-kauran-16β,19-diol (2) and ent-kauran-16β,17,19-triol (3). Their structures were established by 1D and 2D-NMR studies. Both compounds were tested for their action on the growth of radical and shoot of Lactuca sativa.