RESUMEN
Two field experiments were conducted over three growing seasons (2006-07, 2008-09 and 2009-10) to evaluate Se-enriched pasta through foliar fertilization at various rates and timing of application on 4 durum wheat varieties. Our findings confirm the effectiveness of foliar Se fertilization to increase Se concentrations in durum wheat grain, even at high Se rates (120gSeha(-1)). Se fortification was significant across different genotypes, with greater Se accumulation in landraces ('Timilia') and obsolete varieties ('Cappelli'), with respect to modern varieties. The Se content in the grain was increased by up to 35-fold that of the untreated control. The Se concentration decreased during milling (11%), while processing and cooking of pasta did not show significant decreases. This biofortification stategy had no effects on grain quality parameters, except for reduced gluten index in the high-gluten variety PR22D89, as well as for the sensorial properties of the spaghetti.
Asunto(s)
Grano Comestible/clasificación , Alimentos Fortificados , Glútenes/análisis , Selenio/análisis , Triticum/química , Culinaria , Valor Nutritivo , Triticum/genéticaRESUMEN
Metal pollution in water and soil is an environmental and public health issue. Cadmium (Cd) is included in the list of priority hazardous substances in the European Water Framework Directive. Phytoremediation system is a cost-effective, plant-based approach that takes advantage of the ability of plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues. We studied the presence and the importance of an invasive species, such as Lemna minuta, in the environment and the effects of Cd pollution on this species. Growth, removal, and tolerance were evaluated for different Cd concentrations and different times of plant exposure. Overall, the results show that L. minuta has a good capacity of growth, metal bioconcentration, and tolerance up to 3 days of exposure at 0.5 and 1.5 mg L-1 of Cd. In particular, L. minuta was able to accumulate Cd up to 3771 mg kg-1 on dry mass basis. We can conclude that L. minuta possesses a great capability of Cd absorption and accumulation, thus supporting a potential use of this species in designing a metal bioremediation system in phytoremediation field.
Asunto(s)
Araceae/metabolismo , Cadmio/metabolismo , Contaminantes Químicos del Agua/metabolismo , Biodegradación Ambiental , Especies Introducidas , ItaliaRESUMEN
A number of water purification processes have been developed in recent years based on the utilisation of low-cost materials with high pollutant removal efficiency. Among these materials, fly ash and zeolite synthesised from fly ash are two examples of high-efficiency adsorbents. Column absorption tests were performed in order to compare the manganese sorption behaviour of an Italian coal fly ash and zeolite synthesised from it. Different masses of both materials (10-60 g) were exposed to solutions containing a total metal concentration of 10 mg/L. Batch adsorption studies were also conducted to determine the effect of time on the removal on Mn sequestration. The results indicate that both materials are effective for the removal of Mn from aqueous solution by precipitation due to the high pH of the solid/liquid mixtures. However, the leaching tests reveal that the amount of Mn removed from the fly ash was greater than that leached from the zeolite, thereby indicating that the metal is partially sequestrated by zeolite.
Asunto(s)
Ceniza del Carbón/química , Manganeso/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Zeolitas/química , Adsorción , Precipitación Química , SolucionesRESUMEN
Recently, the cloning of the ORF Dr0930 from Deinococcus radiodurans displaying, as primary activity, a lactonase activity and a promiscuous phosphotriesterase activity was reported. The crystal structure of the resulting recombinant enzyme has been solved, and many mutants have been generated in order to increase the phosphotriesterase activity, with the aim to reach the level of activity of the related pPTE from Pseudomonas diminuta. In this paper we report an additional biochemical characterization of DrPLL and show that this enzyme has an optimal temperature for catalysis of 85 °C and possesses promiscuous carboxylesterase, phophodiesterase and thioesterase activities which were not previously described. A metal analysis was performed on the purified protein by inductively coupled plasma mass spectrometry (ICP-MS ELAN DRC-e), which confirmed the presence of Ni(2+) as a main metal in the recombinant protein. Surprisingly, the specificity constants (s=k(cat)/K(M)) for the pNP-decanoate and pNP-dodecanoate esters were only one order of magnitude lower than that for the lactone substrate thio-buthyl-γ-butyric-lactone (TBBL), and the K(M) value for TBBL was more than ten-fold higher than those for the esters. We named this enzyme DrPLL, based on its structural and biochemical features it belongs to the Phosphotriesterase Like Lactonase group, a small protein family belonging to the amidohydrolase superfamily.
Asunto(s)
Amidohidrolasas/metabolismo , Hidrolasas de Éster Carboxílico/metabolismo , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Amidohidrolasas/química , Amidohidrolasas/genética , Hidrolasas de Éster Carboxílico/genética , Deinococcus/enzimología , Deinococcus/genética , Estabilidad de Enzimas , Calor , Espectrometría de Masas , Níquel/análisis , Hidrolasas de Triéster Fosfórico/metabolismo , Espectrofotometría Atómica , Especificidad por SustratoRESUMEN
Recently we reported on the characterization of an archaeal member of the amidohydrolase superfamily, namely Sulfolobus acidocaldarius lactonase, showing low but significant and extremely thermostable paraoxonase activity. This enzyme, that we have named SacPox, is a member of the new described family of phosphotriesterase-like lactonases (PLLs). In this family the binuclear metal centre, which is involved in the catalytic machinery, has been poorly studied up to now. In this work we describe the expression of the protein in presence of different metals showing Mn(2+) to support the higher activity. The enzyme has been over-expressed, purified and characterized as a Mn(2+)-containing enzyme by inductive plasma coupled mass spectrometry (ICP-MS), showing also surprising kinetic differences in comparison with the cadmium-containing enzyme. The Mn(2+) containing enzyme was about 30-fold more efficient with paraoxon as substrate and more stable than the Cd(2+) counterpart, even though the Mn(2+) affinity for the binuclear metal centre is apparently lower. These results increase our knowledge of the biochemical characteristics of SacPox mainly with regard to the metal-ions modulation of function.