Effect of soil composition and dissolved organic matter on pesticide sorption

The effect of the solid and dissolved organic matter fractions, mineral composition and ionic strength of the soil solution on the sorption behaviour of pesticides were studied. A number of soils, chosen so as to have different clay mineral and organic carbon content, were used to study the sorption of the pesticides atrazine (6-chloro-N-2-ethyl-N-4-isopropyl-1,3,5-triazine-2,4-diamine), 2,4-D ((2,4-dichlorophenoxy) acetic acid), isoproturon (3-(4-isopropylphenyl)1,1-dimethylurea) and paraquat (1,1'-dimethyl-4,4'-bipyridinium) in the presence of low and high levels of dissolved organic carbon and different background electrolytes. The sorption behaviour of atrazine, isoproturon and paraquat was dominated by the solid state soil components and the presence of dissolved organic matter had little effect. The sorption of 2,4-D was slightly affected by the soluble organic matter in the soil. However, this effect may be due to competition for adsorption sites between the pesticide and the soluble organic matter rather than due to a positive interaction between the pesticide and the soluble fraction of soil organic matter. It is concluded that the major factor governing the sorption of these pesticides is the solid state organic fraction with the clay mineral content also making a significant contribution. The dissolved organic carbon fraction of the total organic carbon in the soil and the ionic strength of the soil solution appear to have little or no effect on the sorption/transport characteristics of these pesticides over the range of concentrations studied. (C) 2002 Elsevier Science B.V. All rights reserved.

How does residue management impact soil organic matter composition and quality under Eucalyptus globulus plantations in southwestern Australia?

This study investigated the influence of harvest residue management practices on soil organic matter (SOM) composition and quality from two second-rotation Eucalyptus globulus plantations in southwestern Australia, using solid-state 13C nuclear magnetic resonance (NMR) spectroscopy with cross-polarisation and magic-angle-spinning (CPMAS). Soil samples (0–5 cm) were collected every 12 months for 5 years from two sites that had contrasting soil types and fertility. Harvest residue management treatments established at both sites were (a) no harvest residues; and (b) double harvest residues. The use of 13C CPMAS and DD NMR spectroscopy enabled the successful non-destructive detection of SOM quality changes in the two E. globulus plantations. Relative intensities of 13C CPMAS NMR spectral regions were similar at both sites, and for both harvest residue treatments, indicating that SOM composition was also similar. Dipolar dephasing (DD) NMR spectra revealed resonances in SOM assigned to lignin and tannin structures, with larger resonances in the carbonyl and alkyl C regions that were indicative of cuticular material, enabling detection of changes in SOM quality. Retention of double harvest residues on the soil surface increased the soil quality compared with removal of all harvest residues at both sites as indicated by the NMR aromaticities, but this was most noticeable at Manjimup, which had greater initial soil fertility.

The trans-membrane protein p25 forms highly specialized domains that regulate membrane composition and dynamics

Trans-membrane proteins of the p24 family are abundant, oligomeric proteins predominantly found in cis-Golgi membranes. They are not easily studied in vivo and their functions are controversial. We found that p25 can be targeted to the plasma membrane after inactivation of its canonical KKXX motif (KK to SS, p25SS), and that p25SS causes the co-transport of other p24 proteins beyond the Golgi complex, indicating that wild-type p25 plays a crucial role in retaining p24 proteins in cis-Golgi membranes. We then made use of these observations to study the intrinsic properties of these proteins, when present in a different membrane context. At the cell surface, the p25SS mutant segregates away from both the transferrin receptor and markers of lipid rafts, which are enriched in cholesterol and glycosphingolipids. This suggests that p25SS localizes to, or contributes to form, specialized membrane domains, presumably corresponding to oligomers of p25SS and other p24 proteins. Once at the cell surface, p25SS is endocytosed, together with other p24 proteins, and eventually accumulates in late endosomes, where it remains confined to well-defined membrane regions visible by electron microscopy. We find that this p25SS accumulation causes a concomitant accumulation of cholesterol in late endosomes, and an inhibition of their motility - two processes that are functionally linked. Yet, the p25SS-rich regions themselves seem to-exclude not only Lamp1 but also accumulated cholesterol. One may envision that p25SS accumulation, by excluding cholesterol from oligomers, eventually overloads neighboring late endosomal membranes with cholesterol beyond their capacity (see Discussion). In any case, our data show that p25 and presumably other p24 proteins are endowed with the intrinsic capacity to form highly specialized domains that control membrane composition and dynamics. We propose that p25 and other p24 proteins control the fidelity of membrane transport by maintaining cholesterol-poor membranes in the Golgi complex.

Part 2. Carcass composition and fatty acid profiles of adipose tissue of male goats: effects of genotype and liveweight at slaughter

The dissected carcass composition and fatty acid profiles of intermuscular fat from 110 male goat kids from six genotypes i.e. Boer x Angora (BA), Boer x Feral (BF), Boer x Saanen (BS), Feral x Feral (1717), Saanen x Angora (SA) and Saanen x Feral (SF) and two slaughter weight groups i.e. Capretto and Chevon (liveweight at slaughter 14-22 and 30-35 kg, respectively) were compared. Carcass tissue distribution for various genotypes was: muscle (63-66%), fat (10-13%) and bone (21-24%). Genotype significantly (P < 0.05) influenced the carcass composition; BA and FF carcasses had significantly higher muscle to bone ratio, while carcasses from BS kids were leaner compared to other genotypes. However, the two slaughter weight groups did not differ significantly (P > 0.05) in terms of carcass composition, when compared at the same carcass weight. In the present study, significant (P < 0.01) correlations were observed between percentage of muscle, fat and bone in most of the primal cuts and that in the carcass side. The main saturated fatty acids (SFAs) identified were palmitic (16:0) and stearic acid (18:0), while oleic acid (18: 1, omega9) was the main unsaturated fatty acid (UFA) in the intermuscular fat from goat kids. There were significant (P < 0.05) differences between genotypes in the proportions of individual fatty acids. Adipose tissue from BS kids had significantly higher UFAs (mainly oleic acid) and thus had a significantly lower melting point compared to other genotypes. There were significantly higher proportions of palmitic acid (35%) in the adipose tissue from Capretto kids compared to that from Chevon kids (22%). The concentration of UFAs increased in the adipose tissue from Capretto to Chevon carcasses. (C) 2003 Elsevier Science B.V. All rights reserved.

Strawberries from integrated pest management and organic farming: phenolic composition and antioxidant properties

Consumer awareness, pesticide and fertilizer contaminations and environmental concerns have resulted in significant demand for organically grown farm produce. Consumption of berries has become popular among health-conscious consumers due to the high levels of valuable antioxidants, such as anthocyanins and other phenolic compounds. The present study evaluated the influence that organic farming (OF) and integrated pest management (IPM) practise exert on the total phenolic content in 22 strawberry samples from four varieties. Postharvest performance of OF and IPM strawberries grown in the same area in the centre of Portugal and harvested at the same maturity stage were compared. Chemical profiles (phenolic compounds) were determined with the aid of HPLC-DAD/MS. Total phenolic content was higher for OF strawberry extracts. This study showed that the main differences in bioactive phytochemicals between organically and IPM grown strawberries concerned their anthocyanin levels. Organically grown strawberries were significantly higher in antioxidant activity than were the IPM strawberries, as measured by DPPH and FRAP assays.

Molecular mobility, composition and structure analysis in glycerol plasticised chitosan films

This study was developed with the purpose to investigate the effect of polysaccharide/plasticiser concentration on the microstructure and molecular dynamics of polymeric film systems, using transmission electron microscope imaging (TEM) and nuclear magnetic resonance (NMR) techniques. Experiments were carried out in chitosan/glycerol films prepared with solutions of different composition. The films obtained after drying and equilibration were characterised in terms of composition, thickness and water activity. Results show that glycerol quantities used in film forming solutions were responsible for films composition; while polymer/total plasticiser ratio in the solution determined the thickness (and thus structure) of the films. These results were confirmed by TEM. NMR allowed understanding the films molecular rearrangement. Two different behaviours for the two components analysed, water and glycerol were observed: the first is predominantly moving free in the matrix, while glycerol is mainly bounded to the chitosan chain. (C) 2013 Elsevier Ltd. All rights reserved.

Landscape composition and climatic parameters significant in the spread of an invasive species (Pine wood Nematode)

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente

Chemical composition and antifungal activity of essential oil from Eucalyptus smithii against dermatophytes

ABSTRACT INTRODUCTION: In this study, we evaluated the chemical composition of a commercial sample of essential oil from Eucalyptus smithii R.T. Baker and its antifungal activity against Microsporum canis ATCC 32903, Microsporum gypseum ATCC 14683, Trichophyton mentagrophytes ATCC 9533, T. mentagrophytes ATCC 11480, T. mentagrophytes ATCC 11481, and Trichophyton rubrum CCT 5507. METHODS: Morphological changes in these fungi after treatment with the oil were determined by scanning electron microscopy (SEM). The antifungal activity of the oil was determined on the basis of minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values. RESULTS: The compound 1,8-cineole was found to be the predominant component (72.2%) of the essential oil. The MIC values of the oil ranged from 62.5μg·mL−1 to >1,000μg·mL−1, and the MFC values of the oil ranged from 125μg·mL−1 to >1,000μg·mL−1. SEM analysis showed physical damage and morphological alterations in the fungi exposed to this oil. CONCLUSIONS: We demonstrated the potential of Eucalyptus smithii essential oil as a natural therapeutic agent for the treatment of dermatophytosis.

Diversity of sand flies in domiciliary environment of Santarém, state of Pará, Brazil: species composition and abundance patterns in rural and urban areas

This paper aimed to evaluate the richness, abundance and frequency of sand fly occurrence in rural and urban areas American visceral Leishmaniasis -AVL is endemic in the study area of Santarém municipality, Pará state. Sand flies were collected during 1995-2000, using CDC light traps placed in neighborhoods and rural areas of the municipality. A total of 53.454 individuals and 26 species of sand flies were collected. The most abundant species in both urban and rural environments was Lutzomyia longipalpis, vector of AVL in the area. The highest species richness by capture was in rural area. In all years sampled, the largest number of species of sand fly collected was always in rural areas. The species of sand flies in urban and rural area were similar in 11 species. In the rural area other 11 species were found, a total of 22 species. Shannon-Wiener index ranged from 0.12 to 0.84 at rural areas and 0.08 to 0.34 at urban ones. In general, rural localities showed higher diversity (H') of phlebotomines than urban ones. Individual-based rarefaction curves for each area demonstrated that urban localities had the lowest expected number of phlebotomine species and the richest rural ones reach higher expected values with lower amount of individuals than urban sites. The most frequent species were Lutzomyia longipalpis, Evandromyia carmelinoi and Bichromomyia flaviscutellata.

Composition and structure of the fig wasp community in Amazonia

An understanding of the complex ecological interaction between fig wasps and their host plants in Amazonia requires previous knowledge of their distribution and diversity. The objective of this study was to describe the composition and structure of the wasp community associated with four species of Ficus in the municipal area of Manaus, Amazonas, Brazil. A total of 600 syconia from four species were collected. The study species were: Ficus obtusifolia Kunth; Ficus citrifolia Mill; F. americana subspecies guianensis Desv. form mathewsii; and F. americana subspecies guianensis Desv. form parkeriana. Statistical analyses were used to examine the relationship between fig wasp diversity and syconium diameter, and the effect of non-pollinating wasps on numbers of pollinators and seeds. Forty three species of fig wasp were identified, distributed across seven genera (Pegoscapus, Idarnes, Aepocerus, Physothorax, Anidarnes, Heterandrium , Eurytoma). Idarnes (carme group) was the wasps genus non-pollinator with greatest number of individuals with the greatest number of infested syconia (7409 wasps in 376 syconia). Analysing non-pollinating wasp diversity in relation to fig diameter, a significant difference was observed between the four fig species. Ficus citrifolia and F. americana subspecies guianensis form mathewsii had the smallest diameter but the greatest diversity of fig wasp. Ficus obtusifolia was the only species in which the non-pollinating wasps had a significant negative effect on the number of Pegoscapus sp. and on seed production.

Composition and structure variation for magnetron sputtered tantalum oxynitride thin films, as function of deposition parameters

Tantalum oxynitride thin films were produced by magnetron sputtering. The films were deposited usinga pure Ta target and a working atmosphere with a constant N2/O2ratio. The choice of this constant ratiolimits the study concerning the influence of each reactive gas, but allows a deeper understanding of theaspects related to the affinity of Ta to the non-metallic elements and it is economically advantageous.This work begins by analysing the data obtained directly from the film deposition stage, followed bythe analysis of the morphology, composition and structure. For a better understanding regarding theinfluence of the deposition parameters, the analyses are presented by using the following criterion: thefilms were divided into two sets, one of them produced with grounded substrate holder and the otherwith a polarization of −50 V. Each one of these sets was produced with different partial pressure of thereactive gases P(N2+ O2). All the films exhibited a O/N ratio higher than the N/O ratio in the depositionchamber atmosphere. In the case of the films produced with grounded substrate holder, a strong increaseof the O content is observed, associated to the strong decrease of the N content, when P(N2+ O2) is higherthan 0.13 Pa. The higher Ta affinity for O strongly influences the structural evolution of the films. Grazingincidence X-ray diffraction showed that the lower partial pressure films were crystalline, while X-rayreflectivity studies found out that the density of the films depended on the deposition conditions: thehigher the gas pressure, the lower the density. Firstly, a dominant -Ta structure is observed, for lowP(N2+ O2); secondly a fcc-Ta(N,O) structure, for intermediate P(N2+ O2); thirdly, the films are amorphousfor the highest partial pressures. The comparison of the characteristics of both sets of produced TaNxOyfilms are explained, with detail, in the text.

Thin films composed of Ag nanoclusters dispersed in TiO2: Influence of composition and thermal annealing on the microstructure and physical responses

Noble metal powders containing gold and silver have been used for many centuries, providing different colours in the windows of the medieval cathedrals and in ancient Roman glasses. Nowadays, the interest in nanocomposite materials containing noble nanoparticles embedded in dielectric matrices is related with their potential use for a wide range of advanced technological applications. They have been proposed for environmental and biological sensing, tailoring colour of functional coatings, or for surface enhanced Raman spectroscopy. Most of these applications rely on the so-called localised surface plasmon resonance absorption, which is governed by the type of the noble metal nanoparticles, their distribution, size and shape and as well as of the dielectric characteristics of the host matrix. The aim of this work is to study the influence of the composition and thermal annealing on the morphological and structural changes of thin films composed of Ag metal clusters embedded in a dielectric TiO2 matrix. Since changes in size, shape and distribution of the clusters are fundamental parameters for tailoring the properties of plasmonic materials, a set of films with different Ag concentrations was prepared. The optical properties and the thermal behaviour of the films were correlated with the structural and morphological changes promoted by annealing. The films were deposited by DC magnetron sputtering and in order to promote the clustering of the Ag nanoparticles the as-deposited samples were subjected to an in-air annealing protocol. It was demonstrated that the clustering of metallic Ag affects the optical response spectrum and the thermal behaviour of the films.

Development of computational and experimental methods for biomass composition and evaluation of its impact in genome-scale models prediction

The use of genome-scale metabolic models has been rapidly increasing in fields such as metabolic engineering. An important part of a metabolic model is the biomass equation since this reaction will ultimately determine the predictive capacity of the model in terms of essentiality and flux distributions. Thus, in order to obtain a reliable metabolic model the biomass precursors and their coefficients must be as precise as possible. Ideally, determination of the biomass composition would be performed experimentally, but when no experimental data are available this is established by approximation to closely related organisms. Computational methods however, can extract some information from the genome such as amino acid and nucleotide compositions. The main objectives of this study were to compare the biomass composition of several organisms and to evaluate how biomass precursor coefficients affected the predictability of several genome-scale metabolic models by comparing predictions with experimental data in literature. For that, the biomass macromolecular composition was experimentally determined and the amino acid composition was both experimentally and computationally estimated for several organisms. Sensitivity analysis studies were also performed with the Escherichia coli iAF1260 metabolic model concerning specific growth rates and flux distributions. The results obtained suggest that the macromolecular composition is conserved among related organisms. Contrasting, experimental data for amino acid composition seem to have no similarities for related organisms. It was also observed that the impact of macromolecular composition on specific growth rates and flux distributions is larger than the impact of amino acid composition, even when data from closely related organisms are used.

Sewage impact on the composition and distribution of Polychaeta associated to intertidal mussel beds of the Mar del Plata rocky shore, Argentina

The polychaete composition and distribution within mussel beds were studied in order to assess organic pollution due to domestic sewage in a rocky shore of Mar del Plata (Argentina) during 1997. Four stations and a control site were randomly sampled around the local effluent. Quantitative data on polychaetes, as well as sediment accumulated among mussels and its organic carbon content were measured. Polychaete distribution patterns are related to the organic matter gradient, being Capitella cf. capitata, Neanthes succinea (Frey & Leuckart, 1847) and Boccardia polybranchia (Haswell, 1885) the dominant indicator species close to the effluent. At medial distances, the cirratulids Caulleriella alata (Southern, 1914) and Cirratulus cirratus (Müller, 1776) are very important in abundance. The syllids Syllis prolixa Ehlers, 1901 and S. gracilis Grube, 1840 are distributed along the study area, but dominate at the medial stations and at the control site. The orbiniid Protoariciella uncinata Hartmann-Schröder, 1962 is subdominant at the control station.

Composition and diversity of Trichoptera (Insecta) larvae communities in the middle section of the Jacuí river and some tributaries, State of Rio Grande do Sul, Brazil

The taxonomic composition and diversity of Trichoptera larvae communities were studied in four lotic sites in central region of State of Rio Grande do Sul. Sampling was done monthly from June, 2001 to May, 2002 in four sites located at the middle section of Jacuí River (Point 4) and in three tributaries (Carijinho River - Point 1; Lajeado da Gringa - Point 2 and Lajeado do Gringo - Point 3), with a Surber sampler. The total number of larvae collected was 29,143, belonging to 25 genera distributed in nine families; twenty of these genera are new records for the State. The highest abundance was found at Point 2 (n = 12,547). The highest standardized richness, for a 1,177 specimens sample chosen by chance, was recorded at Point 1, followed by Point 4 (17.7 and 16 genera, respectively). The highest diversity was found at Point 1, and the lowest at Point 3 (H' = 1.31 and H' = 0.77, respectively). Point 1 had the lowest anthropic influence and the best preserved riparian vegetation, while Point 3 presented the highest anthropic impact, and a very reduced riparian vegetation. The diversity of Trichoptera observed in this study is low, compared to the estimated maximum theoretical diversity. Low diversity values are related to the low evenness, since the richness was relatively high. The Trichoptera larvae communities seem to be related to the food availability and physical features (riparian vegetation and anthropic influence) of the study sites.