Losses of sediment,organic matter,and nutrients in the Argentinean Pampas through rainfall simulation experiments

Journal of Soils and Sediments - Runoff caused by rainfall events contributes to the watercourses pollution through the export of OM, nutrients, and sediments from soils. This study aimed to assess...     

Combined effects of technical grade fenitrothion, humic acids and particulate matter on cholinesterase activity in freshwater invertebrates

Purpose

The relative sensitivity of two freshwater invertebrate organisms to the organophosphorus insecticide fenitrothion was assessed by measuring cholinesterase (ChE) activity, a well-known biomarker of both exposure and effect to organophosphorus pesticides. The influence of different concentrations of humic acids (HAs) and particulate matter on fenitrothion bioavailability was assessed in the more sensitive species.

Materials and methods

The selected invertebrates were the dwelling feeding oligochaete Lumbriculus variegatus and the pulmonate gastropod Biomphalaria glabrata. Acute 48-h bioassays were performed exposing organisms to different fenitrothion concentrations. The concentrations that induced 50 % inhibition of enzyme activity (EC₅₀) were calculated. Fenitrothion bioavailability was investigated using different concentrations of commercial HA or particulate matter. Sand and a diverse selection of chromatographic resins that have been proposed as analogues of natural sediments were selected. For these experiments, animals were exposed to a fenitrothion value similar to the EC₅₀.

Results and discussion

The 48-h EC₅₀ values were 12?±?2 and 23?±?3 μg?l^?1 for L. variegatus and B. glabrata, respectively. Depending on HA concentration and the characteristics of particles, ChE activity was similar or higher than the value recorded for animals exposed only to the pesticide in aqueous solution.

Conclusion

The results indicated that L. variegatus was the more sensitive species of the two. In this species, fenitrothion bioavailability did not increase due to the presence of either different HA concentrations or particulate matter. The experimental approach may constitute a useful tool to predict the influence of dissolved organic matter and sediment particles on fenitrothion bioavailability and toxicity to non-target aquatic invertebrates.     

Advantages of using non-isothermal bioreactors in agricultural waste water treatment by means of immobilized urease. Study on the influence of spacer length and immobilization method

The behavior of three different catalytic membranes, obtained by immobilizing urease on nylon sheets chemically grafted with methyl methacrylate, was studied in a bioreactor operating under isothermal and non-isothermal conditions. Membrane activation was carried out by condensation or acyl azide reaction, and spacers of different lengths, such as hexamethylendiamine or hydrazine, were used. Under isothermal conditions, the activities of the catalytic membranes and soluble urease were characterized as a function of pH, temperature, and urea concentration. Both enzyme forms showed the same optimum pH, whereas the optimum temperature was lower for the immobilized enzymes. The spacer length appeared to determine broader pH- and temperature-activity profiles for the urease derivatives. The apparent K(m) values of the insoluble urease were dependent on membrane type and were higher than those of the soluble counterpart, thus indicating an affinity loss for urea. Under non-isothermal conditions, all membranes exhibited an increase of percentage activity proportional to the applied temperature difference and decreasing with the increase of urea concentrations. A decrease of the apparent K(m) was also observed. These results suggest that substrate diffusion limitations due to the immobilization process can be overcome in the presence of temperature gradients. In addition, the remarkable reduction of the production times supports the use of non-isothermal bioreactors for the treatment of urea-polluted waste waters.     

Age-Dependent Bioaccumulation of Organochlorine Compounds in Fish and their Selective Biotransformation in Top Predators from Lake Maggiore (Italy)

Fish and piscivorous bird eggs collected in 2003 from Lake Maggiore (Italy), were analysed for PCB and DDT contamination. Lake Maggiore has been severely polluted by DDT through production of the pesticide within its catchment. Although agricultural application of DDT was banned in Italy in the 1978, industrial production continued until 1996, with enough contamination of water and soil for serious bioaccumulation in the lake biota. PCB and DDT concentrations in a whitefish (Coregonus macrophthalmus Nusslin 1882) were seen to be dependent on season and fish age, but not on sex. The average increase of the lipid-normalised concentration of DDTs and PCBs was two-fold across season and also across age, resulting in an overall increase of four fold. The seasonal variation was related to the eco-physiological cycle of the fish and to the contamination dynamic of the lake, while the effect of the fish age was explained on the base of biomagnification-related mechanisms. A fugacity model was applied to predict the age-dependent bioaccumulation potential of PCBs, whose concentrations were rather stable in recent years in the lake. Predicted values for compounds with negligible biotransformation were in good agreement with experimental data (calculated vs. experimental mean difference of 14%), and a relationship between the increase of experimental age-dependent concentration and K _ow was observed. The good correspondence between the predicted and the measured values for most PCB congeners confirmed the general inability of fishes to biotransform these compounds. On the contrary, the importance of biotransformation processes was recognised in birds; eggs of a fish eating bird (Podiceps cristatus) from the same area selectively bioaccumulated p,p′-DDE. For PCBs, congener 149 appears to be completely metabolized by the bird species, and congeners 95, 101, 132, 151 and 174 were reduced as well. The role of the meta–para free position on at least one phenyl ring of PCB congeners in biotransformation processes was confirmed.     

Improved HPLC determination of phenolic compounds in cv. golden delicious apples using a monolithic column

A rapid HPLC-DAD determination of phenols in apple using an RP monolithic column is reported. Because of the hydrodynamic advantages offered by this kind of column and the use of acidified acetonitrile as eluent, assays of apple extracts can be performed in <21 min. Assays of pulp and peel extracts were carried out without the need for time-consuming sample pretreatment except filtration. Several flavanols, hydroxycinnamic acids, dihydrochalcones, and six quercetin glycosides were identified and quantified. A seventh quercetin derivative, two chalcone-related compounds, and three hydroxycinnamic derivatives were also found. Peels proved to be richer in phenols than pulps, the former being composed mainly of (-)-epicatechin, procyanidin B2, chlorogenic acid, phloridzin, hyperin, and avicularin. In pulps, where the chlorogenic acid was the principal phenolic compound, quercetin glycosides were found in very low amounts.     

Green tea protects cytoskeleton from oxidative injury in cardiomyocytes

Cardiac ischemia/reperfusion injury results in oxidative stress and poor physiological recovery. Episodes of hypoxia/reoxygenation (H/R) cause some subtle functional and structural alterations in sarcolemma, mithocondria, sarcoplasmic reticulum, nucleus, as well as cytoskeleton. In this report, by using cultured rat cardiomyocytes and laser confocal microscopy we have verified the possibility to counteract cytoskeleton alterations induced by H/R with the supplementation of an antioxidant agent, a green tea extract (GTE), and compared its effects to those of alpha-tocopherol. Moreover the effects of GTE on cell viability and cytosolic antioxidant activity have been evaluated. H/R induced myocardial damage occurs as histological alterations such as degeneration and disorganization of the cytoskeleton and loss of structural integrity of the nucleus. GTE supplementation increases cytosolic antioxidant activity and shows protective effects on cardiomyocyte cytoarchitecture and viability.     

Crystallization behavior of anhydrous milk fat-sunflower oil wax blends

This research evaluates the effect of sunflower oil wax (SFOw) addition on the crystallization behavior and functional properties of anhydrous milk fat (AMF). Induction times of nucleation, melting behavior, microstructure of crystals, and hardness were evaluated for samples of pure AMF and AMF with 0.1 and 0.25% SFOw. Results from this research show that the addition of waxes induced the onset of crystallization of AMF by inducing its nucleation, as evidenced by decreased induction times of nucleation and the formation of smaller crystals. Crystal growth after tempering was also promoted by waxes, and significantly harder lipid networks were obtained. Results presented in this paper suggest that SFOw can be used as an additive to alter the physiochemical properties of low trans-fatty acid lipids.     

Qualitative traits of perennial wheat lines derived from different Thinopyrum species

Four perennial wheat genotypes derived from crosses between Triticum aestivum and Thinopyrum elongatum, Th. intermedium or Th. ponticum were grown in Central Italy over 2 years of testing, and compared for their agronomical, biochemical, nutritional and technological traits with three commercial common wheat cultivars. Perennial wheat derivatives were characterized by post-harvest regrowth, small kernels, high number of tillers, high protein content and reduced sodium dodecyl sulphate sedimentation volume. Lines 11955 and OK72 exhibited soft kernel texture due to wild-type alleles at the puroindoline loci, whereas lines 235A and 280B produced medium-hard kernels for the presence of novel puroindolines A and B inherited from Th.elongatum and Th. intermedium, respectively. In addition, perennial wheat genotypes presented a high content of carotenoids and 5-n-alkylresorcinols compared with their annual counterparts. AR composition of line 235A, as determined by gas chromatography-mass spectrometry, was characterized by a high percentage (64.7 %) of long-chain (C21:0 + C23:0 + C25:0) homologues, which are claimed to prevent cardiovascular diseases and cancer. In addition, line OK72 was unique in having a C17/C21 homologue ratio as high as 0.34, likely inherited from Th. ponticum. This line along with line 280B also showed a high content of total dietary fiber. Finally, peculiar storage protein composition and kernel texture were observed in some perennial durum wheat derivatives obtained from crosses between T. turgidum subsp. durum and Th. junceiforme. This wheatgrass species was found to contain the 10-mer QQPQDAVQPF peptide, which is able to prevent prolamins from triggering inflammatory responses in celiac patients.     

Influence of carbonization temperature on the anatomical characteristics of Ocotea porosa (Nees & Mart. Ex Nees) L. Barroso

The carbonization process causes different physical and chemical transformations to wood, affecting the final properties of the charcoal produced. In Brazil, the cutting and use of Ocotea porosa (Nees & Mart. Ex Nees) L. Barroso is legally prohibited. But the difficulty of identifying the species used to produce charcoal hinders enforcement efforts to protect this and other endangered tree species. The aim of this work was to characterize the anatomy of charcoal made from O. porosa at different temperatures to provide information to facilitate differentiation of the species by the authorities in charge of suppressing illegal commerce. Samples were carbonized by direct heating and final temperatures of 350, 450 and 650 °C, besides a group under a ramp heating regime also with a final temperature of 450 °C. The qualitative characteristics of the O. porosa wood were preserved at the carbonization temperatures studied permitting the use of its anatomical structures for identification of carbonized wood to support control of the illegal trade in charcoal of this species.