Toxicity and sublethal effects of six insecticides to last instar larvae and adults of the biocontrol agents Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Adalia bipunctata (L.) (Coleoptera: Coccinellidae)

To further develop Integrated Pest Management (IPM) strategies against crop pests, it is important to evaluate the effects of insecticides on biological control agents. Therefore, we tested the toxicity and sublethal effects (fecundity and fertility) of flonicamid, flubendiamide, metaflumizone, spirotetramat, sulfoxaflor and deltamethrin on the natural enemies Chrysoperla carnea and Adalia bipunctata. The side effects of the active ingredients of the insecticides were evaluated with residual contact tests for the larvae and adults of these predators in the laboratory. Flonicamid, flubendiamide, metaflumizone and spirotetramat were innocuous to last instar larvae and adults of C. carnea and A. bipunctata. Sulfoxaflor was slightly toxic to adults of C. carnea and was highly toxic to the L4 larvae of A. bipunctata. For A. bipunctata, sulfoxaflor and deltamethrin were the most damaging compounds with a cumulative larval mortality of 100%. Deltamethrin was also the most toxic compound to larvae and adults of C. carnea. In accordance with the results obtained, the compounds flonicamid, flubendiamide, metaflumizone and spirotetramat might be incorporated into IPM programs in combination with these natural enemies for the control of particular greenhouse pests. Nevertheless, the use of sulfoxaflor and deltamethrin in IPM strategies should be taken into consideration when releasing either of these biological control agents, due to the toxic behavior observed under laboratory conditions. The need for developing sustainable approaches to combine the use of these insecticides and natural enemies within an IPM framework is discussed.

Toxicity of ZnO nanoparticles, ZnO bulk and ZnCl2 on earthworms in a spiked natural soil and toxicological effects of leachates on aquatic organisms

The present study assessed the uptake and toxicity of ZnO nanoparticles (NPs), ZnO bulk, and ZnCl2 salt in earthworms in spiked agricultural soils. In addition, the toxicity of aqueous extracts to Daphnia magna and Chlorella vulgaris was analyzed to determine the risk of these soils to the aquatic compartment. We then investigated the distribution of Zn in soil fractions to interpret the nature of toxicity. Neither mortality nor differences in earthworm body weight were observed compared with the control. The most sensitive end point was reproduction. ZnCl2 was notably toxic in eliminating the production of cocoons. The effects induced by ZnO-NPs and bulk ZnO on fecundity were similar and lower than those of the salt. In contrast to ZnO bulk, ZnO-NPs adversely affected fertility. The internal concentrations of Zn in earthworms in the NP group were greater than those in the salt and bulk groups, although bioconcentration factors were consistently <1. No relationship was found between toxicity and internal Zn amounts in earthworms. The results from the sequential extraction of soil showed that ZnCl2 displayed the highest availability compared with both ZnO. Zn distribution was consistent with the greatest toxicity showed by the salt but not with Zn body concentrations. The soil extracts from both ZnO-NPs and bulk ZnO did not show effects on aquatic organisms (Daphnia and algae) after short-term exposure. However, ZnCl2 extracts (total and 0.45-μm filtered) were toxic to Daphnia.

Bioavailability and extraction of heavy metals from contaminated soil by Atriplex halimus

Pot experiments were performed to evaluate the phytoremediation capacity of plants of Atriplex halimus grown in contaminated mine soils and to investigate the effects of organic amendments on the metal bioavailability and uptake of these metals by plants. Soil samples collected from abandoned mine sites north of Madrid (Spain) were mixed with 0, 30 and 60 Mg ha?1 of two organic amendments, with different pH and nutrients content: pine-bark compost and horse- and sheep-manure compost. The increasing soil organic matter content and pH by the application of manure amendment reduced metal bioavailability in soil stabilising them. The proportion of Cu in the most bioavailable fractions (sum of the water-soluble, exchangeable, acid-soluble and Fe?Mn oxides fractions) decreased with the addition of 60 Mg ha?1 of manure from 62% to 52% in one of the soils studied and from 50% to 30% in the other. This amendment also reduced Zn proportion in water-soluble and exchangeable fractions from 17% to 13% in one of the soils. Manure decreased metal concentrations in shoots of A. halimus, from 97 to 35 mg kg?1 of Cu, from 211 to 98 mg kg?1 of Zn and from 1.4 to 0.6 mg kg?1 of Cd. In these treatments there was a higher plant growth due to the lower metal toxicity and the improvement of nutrients content in soil. This higher growth resulted in a higher total metal accumulation in plant biomass and therefore in a greater amount of metals removed from soil, so manure could be useful for phytoextraction purposes. This amendment increased metal accumulation in shoots from 37 to 138 mg pot?1 of Cu, from 299 to 445 mg pot?1 of Zn and from 1.8 to 3.7 mg pot?1 of Cd. Pine bark amendment did not significantly alter metal availability and its uptake by plants. Plants of A. halimus managed to reduce total Zn concentration in one of the soils from 146 to 130 mg kg?1, but its phytoextraction capacity was insufficient to remediate contaminated soils in the short-to-medium term. However, A. halimus could be, in combination with manure amendment, appropriate for the phytostabilization of metals in mine soils.

Effects of physical exercise and hydration on homocysteine concentrations in physically active male adults = Efectos del ejercicio físico y la hidratación sobre las concentraciones de homocisteína en varones físicamente activos

La presente tesis analiza el efecto del ejercicio físico agudo y la hidratación sobre las concentraciones de homocisteína total (tHcy) y su relación con los parámetros implicados en el metabolismo de la homocisteína como el folato, la vitamina B12, y la creatina en una muestra de varones jóvenes físicamente activos. El trabajo se basa en los resultados del estudio realizado en la Facultad de Ciencias de la Actividad Física y del Deporte de la Universidad Politécnica de Madrid. Para el cual se contó con un total de 29 voluntarios sanos físicamente activos de la Comunidad de Madrid. Los principales resultados de esta tesis son: a) Las concentraciones de tHcy aumentaron después del ejercicio agudo tanto tras una prueba de intensidad máxima (VO2max) como una submáxima (65 % of VO2max) en varones físicamente activos independientemente de las sus concentraciones basales de tHcy. b) Las concentraciones de tHcy disminuyeron 2 h después del ejercicio físico aeróbico submáximo tras aplicar un protocolo de hidratación con una bebida para deportistas. c) Un adecuado protocolo de hidratación durante el ejercicio físico agudo previno el aumento de las concentraciones de tHcy hasta 2 h después del ejercicio. d) Las concentraciones de tHcy aumentaron a las 6 h tras la finalización del ejercicio únicamente en los test en los que no se siguió un protocolo de hidratación durante el ejercicio físico. e) A las 24 h tras el ejercicio, las concentraciones de tHcy volvieron a los niveles basales independientemente de si se aplicó un protocolo de hidratación durante el ejercicio o no. f) Es necesario aclarar si existen mecanismos subyacentes relacionados con el riesgo cardiovascular debido al aumento transitorio de las concentraciones de tHcy inducidas por el ejercicio agudo. Se necesitan más estudios que analicen la relación entre las concentraciones de tHcy después del ejercicio físico agudo y la implicación de la creatina, vitamina B12 y folato como parámetros relacionados en el metabolismo de la homocisteína. El efecto agudo del ejercicio físico aumenta las concentraciones de tHcy por encima de los valores recomendados; sin embargo, un adecuado protocolo de hidratación mantiene las concentraciones a niveles basales y previene el posterior aumento en una muestra de varones adultos físicamente activos. ABSTRACT The current thesis analyzes the effect of exercise and hydration on total homocysteine (tHcy) concentrations and the relationship with the implicated parameters, like folate, vitamin B12, and creatine in physically active male adults. The work is based on the results of the study conducted at the Faculty of Physical Activity and Sport Sciences of the Technical University of Madrid. A total of 29 physically active voluntary healthy males from the Region of Madrid were recruited. The main outcomes of this thesis are: a) tHcy concentrations increased after acute exercise with both, maximal (VO2max) and submaximal (65 % of VO2max) tests in physically active male subjects independently of their baseline tHcy status. b) After 2 h of rehydration with a sport drink, tHcy concentrations, which had previously increased during an acute exercise, decreased significantly, although they didn´t recover to baseline values. c) An adequate hydration protocol during acute aerobic submaximal exercise prevents the increase of tHcy concentrations and maintains these concentrations at baseline up to 2 h post-exercise. d) Serum tHcy concentrations increased after submaximal exercise when the hydration protocol during exercise was not applied. Furthermore, tHcy concentrations reached maximal values 6 h after the end of exercise. e) At 24 h, tHcy concentrations recovered baseline values independently whether or not there was a hydration protocol during exercise. f) There is a need to clarify the underlying mechanisms related to cardiovascular risk due to the transient increase of tHcy concentrations induced by acute exercise. Further research analayzing the relationship between tHcy concentrations after acute exercise and the implication of creatine, vitamin B12 and folate as related parameters in the homocysteine metabolism is needed. Finally, tHcy concentrations increased above the recommended values after an acute aerobic submaximal exercise; nevertheless, a good hydration protocol maintains tHcy concentrations at baseline and prevents the further increase in a sample of physically active male adults.

Amelioration of a degraded acid soil from SW Spain by no-tillage and Ca-amendment

En los suelos, el exceso de acidez lleva asociado deficiencias en ciertos nutrientes y una alta disponibilidad de aluminio, tóxico para los cultivos propios del ambiente mediterráneo. Su laboreo, provoca la pérdida de materia orgánica (MO), deteriora su estructura y reduce la actividad biológica, provocando en última instancia una menor calidad del suelo. Es de esperar pues que cuando se labran suelos ácidos, sus problemáticas particulares tiendan a agravarse. En nuestra zona de estudio, la “raña” de Cañamero (Extremadura, España), predominan los suelos muy ácidos y degradados por un laboreo inadecuado. Las rañas constituyen amplias plataformas casi horizontales, con unos suelos muy viejos (Palexerults), que se caracterizan por tener el complejo de cambio dominado por el aluminio, y un pH ácido que decrece en profundidad. Poseen un potente horizonte Bt rico en arcillas caoliníticas, que propicia que en periodos con exceso de lluvia, se generen capas colgadas de agua cercanas a la superficie. En torno a los años 1940’s estos suelos, que previamente sostenían un alcornocal, o su matorral de sustitución, se pusieron en cultivo. El laboreo aceleró la mineralización de la materia orgánica, agravó los problemas derivados del exceso de acidez y condujo al abandono de los campos cultivados por falta de productividad. Para recuperar la calidad de estos suelos degradados y obtener unos rendimientos compatibles con su uso agrícola es necesario, por un lado, aplicar enmiendas que eleven el pH y reduzcan la toxicidad del aluminio y, por otro, favorecer el incremento en el contenido en MO. En 2005 se implantó en esta raña un ensayo de campo para estudiar la influencia del no laboreo y de la utilización de una enmienda cálcica en parámetros relacionados con la calidad del suelo en un cultivo forrajero. El diseño experimental fue en parcelas divididas con cuatro repeticiones donde el factor principal fue el tipo de laboreo, no laboreo (NL) frente a laboreo convencional (LC), y el factor secundario el uso o no de una enmienda cálcica. La enmienda consistió básicamente en una mezcla de espuma de azucarería y yeso rojo y se incorporó al comienzo del ensayo hasta los 7 cm de profundidad. Desde el comienzo del ensayo el NL influyó positivamente en el contenido de carbono orgánico total (COT) y particulado (COP), mientras que la enmienda tuvo una ligera influencia al principio del ensayo en ambos pero su efecto positivo se desvaneció con el paso del tiempo. Los mayores contenidos en COT y POC se observaron cuando se combinó el NL con la enmienda. La enmienda incrementó con rapidez el pH, y el Ca, y disminuyó el contenido en aluminio hasta una profundidad de 50 cm, incluso en NL, y mejoró ligeramente la agregación del suelo. El NL por sí solo, gracias al aumento en POC, TOC y las proteínas del suelo relacionadas con la glomalina (PSRG), que son capaces de formar compuestos estables no tóxicos con el aluminio, también contribuyó a la reducción de la toxicidad de aluminio en la capa más superficial. Cuando en las campañas con exceso de precipitaciones se generaron capas colgadas de agua próximas a la superficie, el NL generó unas condiciones más favorables para la germinación y desarrollo del cultivo, resultando en una producción más alta que el LC. A ello contribuyó la mayor capacidad de almacenamiento de agua y la mayor transmisividad de esta hacia abajo, en la capa más superficial (0-5 cm) que propició una menor saturación por agua que el LC. Respecto a los parámetros relacionados con la agregación, el NL aumentó los macroagregados hasta los 10 cm de profundidad y favoreció la acumulación de CO y N en todas las fracciones de tamaño de agregados. Sin embargo, la recuperación del grado de macroagregación tras el cese del laboreo resulta lenta en comparación con otros suelos, posiblemente debido al bajo contenido en arcilla en el horizonte Ap. En comparación con el NL, la enmienda mostró también un efecto positivo, aunque muy ligero, en la agregación del suelo. En contradicción con otros estudios en suelos ácidos, nuestros resultados indican la existencia de una jerarquía de agregados, y destacan el papel importante de la MO en la mejora de la agregación. Tanto el NL como la enmienda favorecieron por separado varias propiedades químicas, físicas y biológicas del suelo, pero, en general, encontramos los mayores beneficios con su uso combinado. Además, a largo plazo el efecto positivo de NL en las propiedades del suelo fue en aumento, mientras que el efecto beneficioso de la enmienda se limitó básicamente a las propiedades químicas y se desvaneció en pocos años. Destacamos que las condiciones meteorológicas a lo largo del ensayo beneficiaron la producción de biomasa en NL, y en consecuencia las propiedades relacionadas con la materia orgánica, por lo que son un factor a tener en cuenta a la hora de evaluar los efectos de la enmienda y el laboreo sobre las propiedades del suelo, especialmente en zonas donde esas condiciones son muy variables entre una campaña y otra. Los resultados de este estudio han puesto de manifiesto que el NL no ha mermado la eficacia de la enmienda caliza, posiblemente gracias a la alta solubilidad de la enmienda aplicada, es más, el manejo con NL y enmienda es el que ha favorecido en mayor medida ciertos parámetros de calidad del suelo. Por el contrario el LC sí parece anular los beneficios de la enmienda en relación con las propiedades relacionadas con la MO. Por tanto, cabe concluir que la combinación de NL y la enmienda es una práctica adecuada para mejorar las propiedades químicas y físicas de suelos ácidos degradados por el laboreo. ABSTRACT Excessive acidity in soils is associated with deficiencies in certain nutrients and high concentrations of available aluminum, which is toxic for most Mediterranean crops. Tilling these soils results in the loss of soil organic matter (SOM), damages soil structure and reduces biological activity, ultimately degrading soil quality. It is expected, therefore, that when acid soils are tilled, their particular problems will tend to get worse. In our study area, the "Cañamero’s Raña” (Extremadura, Spain), acid soils degraded by an inappropriate tillage prevail. Rañas are large and flat platforms with very old soils (Palexerults), which are characterized by an exchange complex dominated by aluminum and an acid pH which decreases with depth. These soils have a strong Bt horizon rich in kaolinite clays, which encourages the formation of perched water-tables near the soil surface during periods of excessive rain. During the first third of the 20th century, these soils, that previously supported cork oak or its scrub replacement, were cultivated. Tillage accelerated the mineralization of the SOM, aggravating the problems of excessive acidity, which finally led to the abandonment of the land due to low productivity. To recover the quality of these degraded soils and to obtain consistent yields it is necessary, first, to apply amendments to raise the pH and reduce aluminum toxicity, and second to encourage the accumulation of SOM. In 2005 a field trial was established in the Raña to study the influence of no-tillage and the use of a Ca-amendment on soil quality related parameters in a forage crop agrosystem. The experimental design was a split-plot with four replicates where the main factor was tillage type, no-tillage (NT) versus traditional tillage (TT) and the secondary factor was the use or not of a Ca-amendment. The Ca-amendment was a mixture of sugar foam and red gypsum that was incorporated into the top 7 cm of the soil. Since the beginning of the experiment, NT had a positive influence on total and particulate organic carbon (TOC and POC, respectively), while the Ca-amendment had a small positive influence at the beginning of the study but its effect diminished with time. The highest TOC and POC contents were observed when NT and the Ca-amendment were combined. The Ca-amendment, even under NT, rapidly increased pH and Ca, and decreased the aluminum content to a depth of 50 cm, as well as improving soil aggregation slightly. NT, due to the increased POC, TOC and Glomalin-related soil proteins (GRSP), which can form stable non-toxic compounds with aluminum, also contributed to the reduction of aluminum toxicity in the upper layer. When perched water-tables near the soil surface were formed in campaigns with excessive rainfall, NT provided more favorable conditions for germination and crop development, resulting in higher yields compared with TT. This was directly related to the higher water storage capacity and the greater transmissivity of the water downwards from the upper layers, which led to lower water saturation under NT compared with TT. With regards to the aggregation-related parameters, NT increased macroaggregation to a depth of 10 cm and favored the accumulation of OC and N in all aggregate size fractions. However, the degree of recovery of macroaggregation after tillage ceased was slow compared with other soils, possibly due to the low clay content in the Ap horizon. Compared with NT, the Ca-amendment had a slight positive effect on soil aggregation. In contrast to other studies in acid soils, our results indicate the existence of an aggregate hierarchy, and highlight the important role of SOM in improving aggregation. Both NT and the Ca-amendment separately favored various chemical, physical and biological soil properties, but in general we found the greatest benefits when the two treatments were combined. In addition, the positive effect of NT on soil properties increased with time, while the beneficial effect of the Ca-amendment, which was limited to the chemical properties, vanished after a few years. It is important to note that the meteorological conditions throughout the experiment benefited biomass production under NT and, as a consequence, organic matter related properties. This suggests that meteorological conditions are a factor to consider when evaluating the effects of Ca-amendments and tillage on soil properties, especially in areas where such conditions vary significantly from one campaign to another. The results of this study show that NT did not diminish the effectiveness of the Ca-amendment, possibly due to the high solubility of the selected amendment. Moreover, the combination of NT and the Ca-amendment was actually the management that favored certain soil quality parameters the most. By contrast, TT seemed to nullify the benefits of the Ca-amendment with regards to the OM related properties. In conclusion, the combination of NT and the application of a Ca-amendment is an advisable practice for improving the chemical and physical properties of acid soils degraded by tillage.