Profile of fatty acid lipid fractions of omega-3 fatty acid-enriched table eggs

The omega-3 fatty acid (FA) enrichment of yolk is a key means one of the main objectives to improve the nutraceutical properties of eggs. We evaluated the effect of the dietary inclusion of extruded linseed fed to laying hens on the fatty acid composition of the polar and non-polar lipid classes of the eggs. Two groups of 36 Lohmann White Leghorn layers (65 weeks old) were each fed one of two different diets for a period of 12 weeks. The two diets consisted of a conventional cereal-based diet concentrate (C) and a diet concentrate containing 5% linseed (L). The inclusion of linseed in the diet increased the content of α-linolenic (C18:3n-3), eicosapentaenoic (C20:5n-3) and docosahexaenoic (C22:6n-3) acids in neutral lipids, while a concomitant decrease in arachidonic acid (C20:4n-6) was observed. As regards the polar fraction, the fatty acid composition was slightly affected by the dietary treatments except for C18:0 (+1.14 fold), C18:2n-6 (+1.23 fold), C18:3n-3 (+2.8 fold) and C22:6n-3 (+1.41 fold). Principal component analysis demonstrated that very long-chain FAs were more representative of polar lipids, except for C20:5n-3, while neutral lipids were characterized by dietary n-3 FA (C18:3n-3).     

Profundal macrobenthos structure as a measure of long-term environmental stress in a polluted lake

Profundal macrobenthic community in a polluted lake (Lake Nemi, Italy) was analyzed in three distinct surveys from 1976 to 1984, in order to define long-term changes in environmental conditions of sediments. Profundal macrobenthos was mainly composed of Oligochaeta. Only a few Chironomidae and a few other taxa were characteristically found in the superior zone. The long-term stress, due to persistent hypolimnetic O₂ deficit, caused progressive simplification of the total community structure. This leads to a high faunal similarity among stations at different depths. The temporal trend of the community structure parameters and the significant role of some taxa (Potamothrix heuscheri, Procladius and Chaoborus flavicans) in the eutrophication process of the lake are also discussed.     

The genome of the African trypanosome Trypanosoma brucei

African trypanosomes cause human sleeping sickness and livestock trypanosomiasis in sub-Saharan Africa. We present the sequence and analysis of the 11 megabase-sized chromosomes of Trypanosoma brucei. The 26-megabase genome contains 9068 predicted genes, including approximately 900 pseudogenes and approximately 1700 T. brucei-specific genes. Large subtelomeric arrays contain an archive of 806 variant surface glycoprotein (VSG) genes used by the parasite to evade the mammalian immune system. Most VSG genes are pseudogenes, which may be used to generate expressed mosaic genes by ectopic recombination. Comparisons of the cytoskeleton and endocytic trafficking systems with those of humans and other eukaryotic organisms reveal major differences. A comparison of metabolic pathways encoded by the genomes of T. brucei, T. cruzi, and Leishmania major reveals the least overall metabolic capability in T. brucei and the greatest in L. major. Horizontal transfer of genes of bacterial origin has contributed to some of the metabolic differences in these parasites, and a number of novel potential drug targets have been identified.     

Determination of selenium content in different types of seed oils by cathodic stripping potentiometry (CSP)

Seed oils are consumed worldwide; moreover, they are used in the alimentary, cosmetic, pharmaceutical, and chemical industries. Due to their diffusion, it is interesting to investigate the presence of important micronutrients such as selenium in seed oils. The aim of this work was to develop a rapid, precise, and sensitive cathodic stripping potentiometry (CSP) method to determine the concentration of selenium in different types of seed oils. Selenium was extracted from the oily matrix by concentrated hydrochloric acid treatment at 90 degrees C. The analysis was executed by applying an electrolysis potential of -150 mV for 60 s and a constant current of -30 microA. Under these conditions, detection limits of <0.5 ng g(-1) were obtained. The method reproducibility (expressed as total RSD %) spanned from 0.2 to 0.8%. Recoveries ranged from 92.1 to 97.5%, providing evidence that selenium quantification remained unaffected by the extraction procedure described. The results obtained with the proposed method were compared with those obtained via graphite furnace atomic absorption spectroscopy (GFAAS), a common method for determining selenium. The results of the two methods agreed within 93.5-107.7%. The mean amounts of selenium found were 313.0 +/- 2.0, 458.3 +/- 1.3, 224.6 +/- 0.9, 99.5 +/- 0.8, 332.2 +/- 0.5, 144.0 +/- 0.7, and 295.5 +/- 1.2 ng g(-1), respectively, in peanut, soybean, sunflower, rice, corn, grapestone, and seed oils.     

Electrochemical bioassay for the investigation of chlorpyrifos-methyl in vine samples

This paper reports the optimization of an electrochemical bioassay for the determination of chlorpyrifos-methyl and its application to the analysis of grape and vine leaf samples treated with that pesticide. The analytical method was based on electrochemical determination of the extent of the inhibition exerted by the pesticide on acetylcholinesterase using the substrate acetylthiocholine. Two similar calibration plots were obtained, in the range of 1-300 ng/mL, respectively, for chlorpyrifos-methyl in pure standard form and in the commercial preparation Reldan, with comparable coefficients of variation (CV) in the range of 10% < CV < 20%. After an insecticide treatment, samples were analyzed to evaluate its persistence both in grapes and in vine leaves. Samples were evaluated using different extraction procedures: one based on solvent extraction of pesticide residue from grapes and the other based on aqueous extraction from vine leaves using phosphate buffer. The grape solvent extracts were analyzed using both gas chromatography and electrochemical bioassay, whereas the vine leaf buffer extracts were analyzed using the electrochemical bioassay. Quantitative analysis of chlorpyrifos-methyl determined in the two samples, with the electrochemical bioassay, showed a comparable decrease profile over the experimental period.     

A statistical approach to evaluate compost genotoxicity

Parallel experiments were carried out to evaluate the induction of genotoxic effects in Vicia faba seedlings treated both with aqueous and organic extracts (dimethyl sulphoxide 5%) of 13 composts, or grown on soil samples to which different doses of the same composts were added. Pearsons linear correlation coefficient and multiple regression were used to study how these two different methodological approaches (treatment with the extracts versus direct contact with the composts in soil) agree. In addition, multiple regression analysis was used to investigate the role of heavy metals and humic substances in genotoxic effects and to construct a model to be used to accurately predict potential genotoxicity of the composts. Experimental data obtained at the highest application rate of compost on soil were found to fit the model and evidenced the role of the humic substances in modulating the potential genotoxicity of the different composts.     

Estimating the variance of the sample mean in two-dimensional systematic sampling

This article investigates the problem of estimating the sampling error when the population mean (total) is estimated from a single two-dimensional systematic sample. In particular, two-dimensional extensions of known approximate variance estimators used in linear systematic sampling are introduced. These almost new variance estimators have the advantage of taking into account the spatial ordering of sample units and, consequently, the spatial autocorrelation among them. An investigation of their properties is carried out through a series of simulations and an empirical study.     

From Slope Morphometry to Morphogenetic Processes: An Integrated Approach of Field Survey,Geographic Information System Morphometric Analysis and Statistics in Italian Badlands

Calanchi (singular: calanco) represent a typical example of badlands in the Italian peninsula, which rapidly evolve on clayey terrains such as the widespread Pliocene–Pleistocene marine clays. The present study aimed at investigating the role of the slope morphometry on the typology and distribution of morphogenetic processes in a calanchi area located in southern Italy. The research included detailed geomorphological surveying as well as morphometric and statistical analyses. The study area was first subdivided into individual hydrographic units (HUs), for which field survey allowed to identify the dominant denudation processes, their intensity and the distribution of the associated landforms (pipes, rills, gullies and landslides). The morphometry of each HU was characterised by calculating the morphometric slope index (MSI) on a reconstructed digital elevation model. By statistically comparing the morphogenetic and morphometric data, the influence of the slope morphometry on the type, distribution and evolution of the calanchi erosion process has been highlighted. In particular, through a cluster analysis, the groups of HUs having similar dominant processes were identified, and by applying the analysis of variance, the effect of the MSI on the identified clusters was analysed. Two clusters were identified, which revealed the relative importance of morphogenetic processes and the strict connection between surface and subsurface landforms. These two clusters were discriminated by the MSI value (high MSI favoured mass movements, while low MSI favoured gully erosion and piping), highlighting the importance of slope morphometry in driving the morphogenetic hillslope processes. Copyright © 2015 John Wiley & Sons, Ltd.     

Biocontrol of soil-borne fungal plant diseases by 2,4-diacetylphloroglucinol-producing fluorescent pseudomonads with different restriction profiles of amplified 16S rDNA

Fluorescent pseudomonads producing the antimicrobial compound 2,4-diacetylphloroglucinol (Phl) are being studied extensively for use as biocontrol agents of soil-borne fungal diseases. Some of them can produce pyoluteorin (Plt) in addition to Phl, whereas others synthesise only Phl. Here, a collection of seven Phl⁺ Plt^- pseudomonads, seven Phl⁺ Plt⁺ pseudomonads and seven Phl^- biocontrol pseudomonads were compared for protection of plant roots against fungal pathogens. The seven Phl⁺ Plt⁺ pseudomonads were identical by restriction analysis of amplified spacer ribosomal DNA (spacer ARDRA), whereas the Phl⁺ Plt^- pseudomonads and especially the Phl^- biocontrol pseudomonads were quite diverse by spacer ARDRA. Collectively, the Phl⁺ Plt^- pseudomonads proved superior to the Phl⁺ Plt⁺ pseudomonads and the Phl^- biocontrol pseudomonads for protection of tomato against Fusarium crown and root rot (in rockwool microcosms) or cucumber against Pythium damping-off (in non-sterile soil microcosms). There was no correlation between protection in vivo and inhibition of the corresponding fungal pathogen on plates. However, there was a significant correlation between the amount of Phl produced on plates and protection of tomato against Fusarium crown and root rot, but not with protection of cucumber against Pythium damping-off. Interestingly, the minority of strains unable to produce HCN, an extracellular protease, or both, were among those unable to protect plants in both pathosystems. A seedling assay was developed to compare pseudomonads for suppression of Fusarium crown and root rot in vitro, and a significant correlation was found between disease severity in vitro and in vivo. Overall, results suggest that promising biocontrol pseudomonads may be identified based on the ability to produce Phl and/or specific ARDRA-based fingerprints.