Modified particle swarm optimization for pattern clustering

Data clustering is a common technique for statistical data analysis, which is used in many fields, including machine learning and data mining. Clustering is grouping of a data set or more precisely, the partitioning of a data set into subsets (clusters), so that the data in each subset (ideally) share some common trait according to some defined distance measure. In this paper we present the genetically improved version of particle swarm optimization algorithm which is a population based heuristic search technique derived from the analysis of the particle swarm intelligence and the concepts of genetic algorithms (GA). The algorithm combines the concepts of PSO such as velocity and position update rules together with the concepts of GA such as selection, crossover and mutation. The performance of the above proposed algorithm is evaluated using some benchmark datasets from Machine Learning Repository. The performance of our method is better than k-means and PSO algorithm.

Genetically engineered sensors of cell signaling

Measuring electrical activity in large numbers of cells with high spatial and temporal resolution is a fundamental problem for the study of neural development and information processing. To address this problem, we have constructed FlaSh: a novel, genetically-encoded probe that can be used to measure trans-membrane voltage in single cells. We fused a modified green fluorescent protein (GFP) into a voltage-sensitive potassium channel so that voltage dependent rearrangements in the potassium channel induce changes in the fluorescence of GFP. A voltage sensor encoded into DNA has the advantage that it may be introduced into an organism non-invasively and targeted to specific developmental stages, brain regions, cell types, and sub-cellular compartments.

We also describe modifications to FlaSh that shift its color, kinetics, and dynamic range. We used multiple green fluorescent proteins to produce variants of the FlaSh sensor that generate ratiometric signal output via fluorescence resonance energy transfer (FRET). Finally, we describe initial work toward FlaSh variants that are sensitive to G-protein coupled receptor (GPCR) activation. These sensors can be used to design functional assays for receptor activation in living cells.

Cryopreservation of sperm of common carp, Cyprinus carpio and silver barb, Barbonymus gonionotus for genetically improved seed production

Experiments were conducted to develop and standardize the protocols for cryopreservation of sperm of common carp, Cyprinus carpio and also for using the cryopreserved sperm for fertilization of eggs. Nine extender solutions as Alsever's solution, kurokura-1, kurokura-2, urea egg-yolk, egg-yolk citrate, 0.6% glucose, 0.9% NaCl, Ma and Mb, and five cryoprotectants namely ethanol, methanol, dimethylsulfoxide (DMSO), dimethylamine (DMA) and glycerol were tested. The cryoprotectants were mixed at 10% concentration of the extenders (v/v) to make the cryodiluents. Milt and cryodiluents were mixed at a ratio of 1:9 for Alsever's solution, kurokura-1, kurokura-2, 0.6% glucose and 0.9% NaCl, 1:4 for urea egg-yolk, egg-yolk citrate, Ma and Mb. Among the cryodiluents Alsever's solution mixed with either ethanol or methanol was found to be suitable and it produced more than 90% and 80% spermatozoan motility at equilibrium and post-thaw periods, respectively. Kurokura-1 and kurokura-2 when mixed with the same cryoprotectants showed good spermatozoan motility at equilibrium period (80-90%) but the motility was reduced (30-55%) at post-thaw state. Other extenders did not produce acceptable sperm-motility and in some cases the frozen milt became clotted. Different dilution ratios (1:1, 1:2, 1:4, 1:5, 1:7, 1:9, 1:12, 1:15, 1:20) were formulated for obtaining a suitable milt dilution, the dilution ratio of 1: 9 (milt : cryodiluent) demonstrated the highest post-thaw spermatozoan motility (80%) in Alserver's solution. The optimum concentration of cryoprotectants in the cryodiluents was determined, 10% concentration level was found to be effective to produce the highest number of spermatozoan motility in comparison to the other concentrations (5%, 15%, 20% 30%). Sperm preserved with the cryodiluent Alsever's solution along with either methanol or ethanol was found to be effective to fertilize eggs and produce hatchlings. The hatching rates ranged between 1.48% and 14.76%, compare to control. The fish produced through use of cryopreserved sperm and normal sperm were found to grow well and no significant (P<0.05) growth difference was observed between them. In case of silver barb, Barbonymus gonionotus, sperm tested against six extenders such as egg-yolk citrate, urea-egg-yolk, kurokura-1, kurokura-2, 0.9% NaCl and modified fish ringer (MFR) solution. Cryoprotectants used were the same as those of C. carpio. Milt was diluted with the cryodiluent at a ratio of 1:4 for egg-yolk citrate and urea-egg-yolk, 1:5 for kurokura-1 and 1:9 for 0.9% NaCl, MFR and kurokura-2. The cryoprotectant concentration was maintained at 10% of the extender (v/v) in all the cases. Among the extenders, egg-yolk citrate and urea-egg-yolk mixed with 10% DMSO, methanol and ethanol produced 50% post-thaw spermatozoan motility, whereas DMA and glycerol provided only 10% motility. Trials on milt dilution ratio and cryoprotectant concentration are being conducted. Fertilization trials are also underway.

A genetically engineered thermally responsive sustained release curcumin depot to treat neuroinflammation.

Radiculopathy, a painful neuroinflammation that can accompany intervertebral disc herniation, is associated with locally increased levels of the pro-inflammatory cytokine tumor necrosis factor alpha (TNFα). Systemic administration of TNF antagonists for radiculopathy in the clinic has shown mixed results, and there is growing interest in the local delivery of anti-inflammatory drugs to treat this pathology as well as similar inflammatory events of peripheral nerve injury. Curcumin, a known antagonist of TNFα in multiple cell types and tissues, was chemically modified and conjugated to a thermally responsive elastin-like polypeptide (ELP) to create an injectable depot for sustained, local delivery of curcumin to treat neuroinflammation. ELPs are biopolymers capable of thermally-triggered in situ depot formation that have been successfully employed as drug carriers and biomaterials in several applications. ELP-curcumin conjugates were shown to display high drug loading, rapidly release curcumin in vitro via degradable carbamate bonds, and retain in vitro bioactivity against TNFα-induced cytotoxicity and monocyte activation with IC50 only two-fold higher than curcumin. When injected proximal to the sciatic nerve in mice via intramuscular (i.m.) injection, ELP-curcumin conjugates underwent a thermally triggered soluble-insoluble phase transition, leading to in situ formation of a depot that released curcumin over 4days post-injection and decreased plasma AUC 7-fold.

Implication of modified molecular structure of lipid through heat-related process to fatty acids supply in Brassica carinata seed.

This study was conducted to explore the effect of different autoclave heating times (30, 60 and 90 min) on fatty acids supply and molecular stability in Brassica carinata seed. Multivariate spectral analyses and correlation analyses were also carried out in our study. The results showed that autoclaving treatments significantly decreased the total fatty acids content in a linear fashion in B. carinata seed as heating time increased. Reduced concentrations were also observed in C18:3n3, C20:1, C22:1n9, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), omega 3 (ω-3) and 9 (ω-9) fatty acids. Correspondingly, the heated seeds showed dramatic reductions in all the peak intensities within lipid-related spectral regions. Results from agglomerative hierarchical cluster analysis (AHCA) and principal component analysis (PCA) indicated that the raw oilseed had completely different structural make-up from the autoclaved seeds in both CH3 and CH2 asymmetric and symmetric stretching region (ca. 2999–2800 cm−1) and lipid ester Cdouble bond; length as m-dashO carbonyl region (ca. 1787–1706 cm−1). However, the oilseeds heated for 30, 60 and 90 min were not grouped into separate classes or ellipses in all the lipid-related regions, indicating that there still exhibited similarities in lipid biopolymer conformations among autoclaved B. carinata seeds. Moreover, strong correlations between spectral information and fatty acid compositions observed in our study could imply that lipid-related spectral parameters might have a potential to predict some fatty acids content in oilseed samples, i.e. B. carinata. However, more data from large sample size and diverse range would be necessary and helpful to draw up a final conclusion.

Biosensor based on multi-walled carbon nanotubes paste electrode modified with laccase for pirimicarb pesticide quantification

This study focused on the development of a sensitive enzymatic biosensor for the determination of pirimicarb pesticide based on the immobilization of laccase on composite carbon paste electrodes. Multi- walled carbon nanotubes(MWCNTs)paste electrode modified by dispersion of laccase(3%,w/w) within the optimum composite matrix(60:40%,w/w,MWCNTs and paraffin binder)showed the best performance, with excellent electron transfer kinetic and catalytic effects related to the redox process of the substrate4- aminophenol. No metal or anti-interference membrane was added. Based on the inhibition of laccase activity, pirimicarb can be determined in the range 9.90 ×10- 7 to 1.15 ×10- 5 molL 1 using 4- aminophenol as substrate at the optimum pH of 5.0, with acceptable repeatability and reproducibility (relative standard deviations lower than 5%).The limit of detection obtained was 1.8 × 10-7 molL 1 (0.04 mgkg 1 on a fresh weight vegetable basis).The high activity and catalytic properties of the laccase- based biosensor are retained during ca. one month. The optimized electroanalytical protocol coupled to the QuEChERS methodology were applied to tomato and lettuce samples spiked at three levels; recoveries ranging from 91.0±0.1% to 101.0 ± 0.3% were attained. No significant effects in the pirimicarb electro- analysis were observed by the presence of pro-vitamin A, vitamins B1 and C,and glucose in the vegetable extracts. The proposed biosensor- based pesticide residue methodology fulfills all requisites to be used in implementation of food safety programs.

The effect of feeding modified soyabean oil enriched with C18 : 4 n-3 to broilers on the deposition of n-3 fatty acids in chicken meat

Supplementing broiler diets with conventional vegetable oils has little effect on the long-chain n-3 PUFA (LC n-3 PUFA) content of the meat. The present study investigated the effect on fatty acid composition and sensory characteristics of chicken meat when broilers were fed oil extracted from soyabeans (SDASOY) that had been genetically engineered to produce C18 : 4n-3 (stearidonic acid (SDA), 240 mg/g oil). Three diets were fed to 120 birds (eight replicate pens of five birds) from 15 d to slaughter (41–50 d). Diets were identical apart from the oil added to them (45 and 50 g/kg as fed in the grower and finisher phases, respectively), which was either SDASOY, near-isogenic soya (CON) or fish oil (FISH). The LC n-3 PUFA content of the meat increased in the order CON, SDASOY and FISH. In breast meat with skin, the SDA concentration was 522, 13 and 37 (sem 14·4) mg/100 g meat for SDASOY, CON and FISH, respectively. Equivalent values for C20 : 5n-3 (EPA) were 53, 13 and 140 (sem 8·4); for C22 : 5n-3 (docosapentaenoic acid (DPA)) 65, 15 and 101 (sem 3·5); for C22 : 6n-3 (DHA) 19, 9 and 181 (sem 4·4). Leg meat (with skin) values for SDA were 861, 23 and 68 (sem 30·1); for EPA 87, 9 and 258 (sem 7·5); for DPA 95, 20 and 165 (sem 5·0); for DHA 29, 10 and 278 (sem 8·4). Aroma, taste and aftertaste of freshly cooked breast meat were not affected. Fishy aromas, tastes and aftertastes were associated with LC n-3 PUFA content of the meat, being most noticeable in the FISH leg meat (both freshly cooked and reheated) and in the reheated SDASOY leg meat.

The impact of secondary pests on Bacillus thuringiensis (Bt) crops

The intensification of agriculture and the development of synthetic insecticides enabled worldwide grain production to more than double in the last third of the 20th century. However, the heavy dependence and, in some cases, overuse of insecticides has been responsible for negative environmental and ecological impacts across the globe, such as a reduction in biodiversity, insect resistance to pesticides, negative effects on nontarget species (e.g. natural enemies) and the development of secondary pests. The use of recombinant DNA technology to develop genetically engineered (GE) insect resistant crops could mitigate many of the negative side effects of pesticides. One such genetic alteration enables crops to express toxic crystalline (Cry) proteins from the soil bacteria Bacillus thuringiensis (Bt). Despite the widespread adoption of Bt crops, there are still a range of unanswered questions concerning longer term agro-ecosystem interactions. For instance, insect species that are not susceptible to the expressed toxin can develop into secondary pests and cause significant damage to the crop. Here we review the main causes surrounding secondary pest dynamics in Bt crops and the impact of such outbreaks. Regardless of the causes, if non-susceptible secondary pest populations exceed economic thresholds, insecticide spraying could become the immediate solution at farmers’ disposal, and the sustainable use of this genetic modification technology may be in jeopardy. Based on the literature, recommendations for future research are outlined that will help to improve the knowledge of the possible longterm ecological trophic interactions of employing this technology.

JULES-crop: a parametrisation of crops in the Joint UK Land Environment Simulator

Studies of climate change impacts on the terrestrial biosphere have been completed without recognition of the integrated nature of the biosphere. Improved assessment of the impacts of climate change on food and water security requires the development and use of models not only representing each component but also their interactions. To meet this requirement the Joint UK Land Environment Simulator (JULES) land surface model has been modified to include a generic parametrisation of annual crops. The new model, JULES-crop, is described and evaluation at global and site levels for the four globally important crops; wheat, soybean, maize and rice. JULES-crop demonstrates skill in simulating the inter-annual variations of yield for maize and soybean at the global and country levels, and for wheat for major spring wheat producing countries. The impact of the new parametrisation, compared to the standard configuration, on the simulation of surface heat fluxes is largely an alteration of the partitioning between latent and sensible heat fluxes during the later part of the growing season. Further evaluation at the site level shows the model captures the seasonality of leaf area index, gross primary production and canopy height better than in the standard JULES. However, this does not lead to an improvement in the simulation of sensible and latent heat fluxes. The performance of JULES-crop from both an Earth system and crop yield model perspective is encouraging. However, more effort is needed to develop the parametrisation of the model for specific applications. Key future model developments identified include the introduction of processes such as irrigation and nitrogen limitation which will enable better representation of the spatial variability in yield.

Phenolic matrices and sisal fibers modified with hydroxy terminated polybutadiene rubber: Impact strength, water absorption, and morphological aspects of thermosets and composites

The aim of the present work was to investigate the toughening of phenolic thermoset and its composites reinforced with sisal fibers, using hydroxyl-terminated polybutadiene rubber (HTPB) as both impact modifier and coupling agent. Substantial increase in the impact strength of the thermoset was achieved by the addition 10% of HTPB. Scanning electron microscopy (SEM) images of the material with 15% HTPB content revealed the formation of some rubber aggregates that reduced the efficiency of the toughening mechanism. In composites, the toughening effect was observed only when 2.5% of HTPB was added. The rubber aggregates were found located mainly at the matrix-fiber interface suggesting that HTPB could be used as coupling agent between the sisal fibers and the phenolic matrix. A composite reinforced with sisal fibers pre-impregnated with HTPB was then prepared; its SEM images showed the formation of a thin coating of HTPB on the surface of the fibers. The ability of HTBP as coupling agent between sisal fibers and phenolic matrix was then investigated by preparing a composite reinforced with sisal fibers pre-treated with HTPB. As revealed by its SEM images, the HTPB pre-treatment of the fibers resulted on the formation of a thin coating of HTPB on the surface of the fibers, which provided better compatibility between the fibers and the matrix at their interface, resulting in a material with low water absorption capacity and no loss of impact strength. (C) 2009 Elsevier B.V. All rights reserved.

Environmental ageing studies of chemically modified micro and nanofibril phenol formaldehyde composites

Cellulose micro and nano fibrils were extracted from banana macro fibres and chemically modified using sodium hydroxide, formic acid, 3-methacryloxy propyltrimethoxy silane. These untreated and chemically treated fibrils were incorporated into PF resin and the specimens were prepared. The composites were subjected to long-term water ageing, thermal ageing soil burial and outdoor weathering. The mechanical properties are reduced under all ageing conditions. The present study investigates the effects of different types of ageing on macro fibre, microfibril and nanofibril reinforced PF composites. The effect of chemical modifications of fibres on the degradability of the composites at different environments also has been analysed. © 2013 Elsevier B.V.

Obtenção de plantas transgênicas de soja com a forma constitutiva do fator de transcrição AREB1

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Process for genetically engineering acidophilic bacteria and constructing a transformation vector

The present invention describes a method for transforming chemolithotrophic acidophilic bacteria using electroporation technology. The proposed method allows transforming a bacterial line using a transformation vector, the pAF vector, which contains an origin of vegetative replication that allows the vector to replicate inside the bacteria without altering the natural physiological functions of the latter. Also disclosed is the use of the bacteria modified according to the invention in bioleaching processes of sulphated copper, gold, uranium, nickel, zinc and cobalt ore, inter alia.

TILLING for Mutations in Model Plants and Crops

A growing world population, changing climate and limiting fossil fuels will provide new pressures on human production of food, medicine, fuels and feed stock in the twenty-first century. Enhanced crop production promises to ameliorate these pressures. Crops can be bred for increased yields of calories, starch, nutrients, natural medicinal compounds, and other important products. Enhanced resistance to biotic and abiotic stresses can be introduced, toxins removed, and industrial qualities such as fibre strength and biofuel per mass can be increased. Induced and natural mutations provide a powerful method for the generation of heritable enhanced traits. While mainly exploited in forward, phenotype driven, approaches, the rapid accumulation of plant genomic sequence information and hypotheses regarding gene function allows the use of mutations in reverse genetic approaches to identify lesions in specific target genes. Such gene-driven approaches promise to speed up the process of creating novel phenotypes, and can enable the generation of phenotypes unobtainable by traditional forward methods. TILLING (Targeting Induced Local Lesions IN Genome) is a high-throughput and low cost reverse genetic method for the discovery of induced mutations. The method has been modified for the identification of natural nucleotide polymorphisms, a process called Ecotilling. The methods are general and have been applied to many species, including a variety of different crops. In this chapter the current status of the TILLING and Ecotilling methods and provide an overview of progress in applying these methods to different plant species, with a focus on work related to food production for developing nations.

Influence of new integrated pest management strategies on aphidophagous predators in horticultural crops

El 1 de enero de 2014 entró en vigor la Directiva Europea 2009/128/CE sobre uso sostenible de plaguicidas y el Real Decreto 1311/2012 por el cual se traspone dicha normativa comunitaria al ámbito nacional. Estos reglamentos establecen el marco legal por el que las explotaciones agrícolas deben cumplir los principios generales de la Gestión Integrada de Plagas (GIP). Los principios de la GIP dan preferencia a aquellos métodos de control que sean sostenibles y respetuosos con el medio ambiente, dando prioridad al control biológico, al físico y a otros de carácter no químico. Sin embargo, el uso de insecticidas selectivos con los enemigos naturales es necesario en ocasiones para el adecuado manejo de las plagas en cultivos hortícolas. Por ello, el objetivo general de esta Tesis ha sido aportar conocimientos para la mejora del control de plagas en cultivos hortícolas, mediante la integración de estrategias de lucha biológica, física y química. La primera de las líneas de investigación de esta Tesis se centró en el estudio del efecto de la presencia dos depredadores, larvas Chrysoperla carnea y adultos de Adalia bipunctata, en la dispersión del virus de transmisión no persistente Cucumber mosaic virus (CMV) y del virus de transmisión persistente Cucurbit aphid-borne yellows virus (CABYV), transmitidos por el pulgón Aphis gosypii en cultivo de pepino. La tasa de transmisión de CMV fue baja para los dos tiempos de evaluación ensayados (1 y 5 días), debido al limitado movimiento de su vector A. gossypii. Las plantas que resultaron infectadas se localizaron próximas a la fuente de inóculo central y la presencia de ambos enemigos naturales no incrementó significativamente el porcentaje de plantas ocupadas por pulgones ni la tasa de transmisión de CMV. Los patrones de distribución de A. gossypii y de CMV tan solo fueron coincidentes en las proximidades de la planta central infectada en la que se liberaron los insectos. En los ensayos con CABYV, la presencia de C. carnea y de A. bipunctata respectivamente provocó un incremento significativo de la dispersión de A. gossypii tras 14 días, pero no tras 7 días desde la liberación de los insectos. La reducción en el número inicial de pulgones en la planta central infectada con CABYV fue siempre mayor tras la liberación de C. carnea en comparación con A. bipunctata. Sin embargo, la tasa de transmisión de CABYV y su distribución espacial no se vieron significativamente modificadas por la presencia de ninguno de los depredadores, ni tras 7 días ni tras 14 días desde el inicio de los ensayos. Al igual que se estudió el efecto de la presencia de enemigos naturales en el comportamiento de las plagas y en la epidemiología de las virosis que transmiten, en una segunda línea de investigación se evaluó el posible efecto del consumo de pulgones portadores de virus por parte de los enemigos naturales. Este trabajo se llevó a cabo en el Laboratorio de Ecotoxicología del Departamento de Entomología de la Universidade Federal de Lavras (UFLA) (Brasil). En él se evaluó la influencia en los parámetros biológicos del enemigo natural Chrysoperla externa al alimentarse de Myzus persicae contaminados con el virus de transmisión persistente Potato leafroll virus (PLRV). El consumo de M. persicae contaminados con PLRV incrementó significativamente la duración de la fase larvaria, reduciendo también la supervivencia en comparación a otras dos dietas a base de M. persicae no contaminados con el virus y huevos del lepidóptero Ephestia kuehniella. La duración de la fase de pupa de C. externa no difirió significativamente entre las dietas a base de pulgones contaminados con PLRV y pulgones no contaminados, pero ambas fueron menores que con la dieta con huevos de E. kuehniella. Sin embargo, ni la supervivencia en la fase de pupa ni los parámetros reproductivos de los adultos emergidos mostraron diferencias significativas entre las dietas evaluadas. Por el contrario, la supervivencia de los adultos durante los 30 primeros días desde su emergencia sí se vio significativamente afectada por la dieta, siendo al término de este periodo del 54% para aquellos adultos de C. externa que durante su fase larvaria consumieron pulgones con PLRV. Dentro de la GIP, una de las estrategias de carácter físico que se emplean para el control de plagas y enfermedades en cultivos hortícolas protegidos es el uso de plásticos con propiedades fotoselectivas de absorción de la radiación ultravioleta (UV). Por ello, la tercera línea de investigación de la Tesis se centró en el estudio de los efectos directos e indirectos (mediados por la planta) de condiciones especiales de baja radiación UV sobre el crecimiento poblacional del pulgón A. gossypii y los parámetros biológicos del enemigo natural C. carnea, así como sobre las plantas de pepino en las que se liberaron los insectos. Los ensayos se realizaron en jaulones dentro de invernadero, utilizándose en el primero de ellos plantas de pepino sanas, mientras que en el segundo las plantas de pepino fueron previamente infectadas con CABYV para estudiar de qué manera afectaba la incidencia del virus en las mismas condiciones. Las condiciones de baja radiación UV (bajo plástico Térmico Antivirus®) ejercieron un efecto directo en las fases iniciales del cultivo de pepino, promoviendo su crecimiento, mientras que en fases más avanzadas del cultivo indujeron un aumento en el contenido en nitrógeno de las plantas. Las plantas de pepino que fueron sometidas a mayor intensidad de radiación UV (bajo plástico Térmico Blanco®) al inicio del cultivo mostraron un engrosamiento significativo de las paredes de las células epidérmicas del haz de las hojas, así como de la cutícula. El uso del plástico Térmico Antivirus®, utilizado como barrera fotoselectiva para crear condiciones de baja radiación UV, no alteró con respecto al plástico Térmico Blanco® (utilizado como control) el desarrollo poblacional del pulgón A. gossypii ni los parámetros biológicos evaluados en el depredador C. carnea. En el segundo experimento, realizado con plantas infectadas con CABYV, la incidencia de la virosis enmascaró las diferencias encontradas en experimento con plantas sanas, reduciendo aparentemente la influencia de las distintas condiciones de radiación UV. Por último, para el desarrollo de las estrategias de GIP es importante estudiar los posibles efectos secundarios que los plaguicidas pueden tener en los enemigos naturales de las plagas. Es por ello que en la Tesis se evaluaron la toxicidad y los efectos subletales (fecundidad y fertilidad) de flonicamida, flubendiamida, metaflumizona, spirotetramat, sulfoxaflor y deltametrina en los enemigos naturales C. carnea y A. bipunctata. Los efectos secundarios fueron evaluados por contacto residual tanto para larvas como para adultos de ambos enemigos naturales en condiciones de laboratorio. Flonicamida, flubendiamida, metaflumizona y spirotetramat fueron inocuos para larvas de último estadio y adultos de C. carnea y A. bipunctata. Por este motivo, estos insecticidas se presentan como buenos candidatos para ser incorporados dentro de programas de GIP en combinación con estos enemigos naturales para el control de plagas de cultivos hortícolas. Sulfoxaflor fue ligeramente tóxico para adultos de C. carnea y altamente tóxico para larvas de último estadio de A. bipunctata. Para A. bipunctata, sulfoxaflor y deltametrina fueron los compuestos más dañinos. Deltametrina fue también el compuesto más tóxico para larvas y adultos de C. carnea. Por tanto, el uso de deltametrina y sulfoxaflor en programas de GIP debería tomarse en consideración cuando se liberasen cualquiera de estos dos enemigos naturales debido al comportamiento tóxico que mostraron en condiciones de laboratorio. ABSTRACT On 1 January 2014 came into effect the Directive 2009/128/EC of the European Parliament about sustainable use of pesticides and the Royal Decree 1311/2012 that transposes the regulation to the Spanish level. These regulations establish the legal framework that agricultural holdings must adhere to in order to accomplish the general principles of Integrated Pest Management (IPM). The guidelines of IPM give priority to sustainable and eco-friendly pest control techniques, such as biological and physical measures. Nevertheless, the use of pesticides that are selective to natural enemies is sometimes a necessary strategy to implement accurate pest management programs in horticultural protected crops. Therefore, the general objective of this Thesis was to contribute to the improvement of pest management strategies in horticultural crops, by means of the integration of biological, physical and chemical techniques. The first research line of this Thesis was focused on the evaluation of the effects of two aphidophagous predators, Chrysoperla carnea larvae and Adalia bipunctata adults, on the spread of the non-persistently transmitted Cucumber mosaic virus (CMV, Cucumovirus) and the persistently transmitted Cucurbit aphid-borne yellows virus (CABYV, Polerovirus), by the aphid vector Aphis gossypii in a cucumber crop under greenhouse conditions. The CMV transmission rate was generally low, both after 1 and 5 days, due to the limited movement of its aphid vector A. gossypii. Infected plants were mainly located around the central virusinfected source plant, and the percentage of aphid occupation and CMV-infected plants did not differ significantly in absence and presence of natural enemies. The distribution patterns of A. gossypii and CMV were only coincident close to the central plant where insects were released. In the CABYV experiments, the presence of C. carnea larvae and A. bipunctata adults induced significant A. gossypii dispersal after 14 days but not after 7 days. The reduction in the initial aphid population established in the central plant was always higher for C. carnea than for A. bipunctata. Nevertheless, CABYV spread was not significantly modified by the presence of each predator either in the short term (7 days) or in the long term (14 days). Furthermore, the percentage of CABYV-infected plants did not significantly differ when each natural enemy was present in any evaluation period. It is important to evaluate the influence that natural enemies have on pest dynamics and on the spread of viral diseases, but it should be also taken into account the possible effect on the performance of natural enemies when they feed on preys that act as vectors of viruses. Thus, in a second research line developed in the Laboratory of Ecotoxicology, Department of Entomology, of the Universidade Federal de Lavras (UFLA) (Brazil), it was evaluated the performance of Chrysoperla externa under the condition of consuming Myzus persicae acting as vector of Potato leafroll virus (PLRV). The diet composed of PLRV-infected M. persicae significantly increased the length and reduced the survival rate, of the larval period in regard to the other two diets, composed of non-infected M. persicae and Ephestia kuehniella eggs. The lengths of the pupal stage were not significantly different between the aphid diets, but both were significantly shorter than that of E. kuehniella eggs. Neither pupal survival nor reproductive parameters revealed significant differences among the diets. Nevertheless, the adult survival curves during the first 30 days after emergence showed significant differences, reaching at the end of this interval a value of 54% for those C. externa adults fed on PLRVinfected aphids during their larval period. According to the IPM guidelines, one of the physical strategies for the control of pests and diseases in horticultural protected crops is the use of plastic films with photoselective properties that act as ultraviolet (UV) radiation blocking barriers. In this sense, the third research line of the Thesis dealt with the study of the direct and plant-mediated influence of low UV radiation conditions on the performance of the aphid A. gossypii and on the biological parameters of the natural enemy C. carnea, as well as on the cucumber plants where insects were released. The experiments were conducted inside cages under greenhouse conditions, using for the first one healthy cucumber plants, while for the second experiment the cucumber plants were previously infected with CABYV in order to assess the influence of the virus in the same conditions. The low UV radiation conditions (under Térmico Antivirus® plastic film) seemed to exert a direct effect in the early stages of cucumber plants, enhancing their growth, and in an increasing nitrogen content at further developmental stages. The higher UV radiation exposure (under Térmico Blanco® plastic film) in the early stages of the cucumber crop induced the thickening of the adaxial epidermal cell walls and the cuticle of leaves. The use of Térmico Antivirus® plastic film as a photoselective barrier to induce low UV radiation conditions did not modify, in regard to Térmico Blanco® plastic film (used as control), neither the population development of A. gossypii nor the studied biological parameters of the predator C. carnea. In the second experiment, done with CABYV-infected cucumber plants, the incidence of the virus seemed to mask the direct and plant-mediated influence of the different UV radiation conditions. In last term, for the development of IPM strategies it is important to study the potential side effects that pesticides might have on natural enemies. For this reason, in the Thesis were tested the toxicity and sublethal effects (fecundity and fertility) of flonicamid, flubendiamide, metaflumizone, spirotetramat, sulfoxaflor and deltamethrin on the natural enemies C. carnea and A. 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 under laboratory conditions. Flonicamid, flubendiamide, metaflumizone and spirotetramat were innocuous to last instar larvae and adults of C. carnea and A. bipunctata. Therefore, these pesticides are promising candidates for being incorporated into IPM programs in combination with these natural enemies for the control of particular greenhouse pests. In contrast, sulfoxaflor was slightly toxic to adults of C. carnea and was highly toxic to last instar larvae of A. bipunctata. For A. bipunctata, sulfoxaflor and deltamethrin were the most damaging compounds. Deltamethrin was also the most toxic compound to larvae and adults of C. carnea. In accordance with this fact, 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.