Fluctuaci\uf3n poblacional de Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) en el cultivo de ma\uedz bajo tres sistemas de labranza

Pi\uf1ango L, Arnal E, Rodr\uedguez B. 2001. Population fluctuation of Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) on corn under three tillage systems. Entomotropica 16(3):173-179. Populations of the fall armyworm Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) on corn were evaluated to determine the effect of three tillage systems. The tested tillage systems were no-tillage (SD), conventional tillage (LC) and no-tillage with previous chisel pass (CSD). A randomized complete blocks design was used with three repetitions with treatments arranged in split plots. The study was conducted at Tierra Nueva farm during the year 1997, Municipality of Urdaneta, State of Aragua. Populations of the fall armyworm were evaluated weekly by choosing randomly twelve points inside each plot, each point with an area of 1 m2. In each point were determined: total number of plants, number of damaged plants, number of larvae, and number of infested plants. 20 larvae/ plot were collected at random; they were reared in the laboratory with artificial diet until adult emergency, for checking insidence of natural enemies. Infestation by the armyworm was 26.63 % in LC, 24.61% in CSD and 7.79% SD. Infestation reached its maximum (53.89%) to the 27 day after planting (DAP) and 66 DAP (34.34%). The number of larvae/plant was of 0.39 in LC, 0.36 in CSD and 0.24 in SD. The maximum observed values were 0.88 larvae/ plant were 21 DAP and 0.46 larvae/ plant 66 DAP. Parasitoids were identified as Meteorus laphygmae Viereck and Chelonus texanus Cresson (Hymenoptera: Braconidae) and flies of the genera Archytas sp. and Winthemia sp. (Diptera: Tachinidae). Entomopathogens found were fungi of the genus Paecilomyces , bacteria of the genus Erwinia and viruses. Total mortality observed was 41.76% in SD, 45.01% in CSD and 40.50% in LC. Mortality due to parasitism and diseases was 10.15% and 31.61% in SD; 12.10% and 32.91% in CSD and 13.16% and 27.34% in LC, respectively.Pi\uf1ango L, Arnal E, Rodr\uedguez B. 2001. Fluctuaci\uf3n poblacional de Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) en el cultivo de ma\uedz bajo tres sistemas de labranza. Entomotropica 16(3):173-179. Poblaciones del gusano cogollero, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) fueron evaluadas en el cultivo de ma\uedz, sometido a tres sistemas de labranza: labranza convencional (LC), siembra directa (SD) y siembra directa previo un pase de cincel (CSD), usando un bloques al azar con tres repeticiones con arreglo de los tratamientos en parcelas divididas. El estudio se realiz\uf3 en la Agropecuaria Tierra Nueva, Municipio Urdaneta del estado Aragua, durante el per\uedodo junio - septiembre del a\uf1o 1997. Las poblaciones del gusano cogollero se muestrearon semanalmente, escogiendo doce puntos al azar dentro de cada parcela. Posteriormente se midi\uf3 1 m2 por punto; en esta \ue1rea se determin\uf3 n\ufamero de: plantas, plantas infestadas y larvas/planta. Igualmente, se colectaron al azar 20 larvas/parcela; las cuales fueron criadas en el laboratorio con dieta artificial hasta la emergencia del adulto, observ\ue1ndose la incidencia de parasitoides y entomopat\uf3genos. Los porcentajes de plantas infestadas fueron: 26,63% en LC, 24,61% en CSD y 7,79% SD. En el per\uedodo de crecimiento del ma\uedz, la infestaci\uf3n alcanz\uf3 sus m\ue1ximos poblacionales a los 27 y 66 d\uedas despu\ue9s de la emergencia (DDE). Los niveles poblacionales de larvas/planta en los sistemas de labranza fueron: 0,40 en LC, 0,36 en CSD y 0,24 en SD. Los valores m\ue1ximos observados en la fluctuaci\uf3n poblacional correspondieron a: 0,88 larvas/planta a los 21 DDE y 0,46 larvas/planta a los 66 DDE. Se identificaron las avispas Meteorus laphygmae Viereck y Chelonus texanus Cresson (Hymenoptera: Braconidae) y las moscas de los g\ue9neros Archytas sp. y Winthemia sp. (Diptera: Tachinidae). Los entomopat\uf3genos encontrados fueron: un hongo del g\ue9nero Paecilomyces sp., bacterias del g\ue9nero Erwinia sp. y virus no determinados. Los porcentajes de mortalidad total fueron: 41,76% en SD, 45,01% en CSD y 40,50% en LC. Los niveles correspondientes a parasitismo y enfermedades alcanzaron valores de: 10,15 y 31,61%; 12,10 y 32,91% y 13,16 y 27,34% en SD, CSD y LC respectivamente

Abundance and diversity of Scelionidae (Hymenoptera: Platygastroidea), in cacao plantations in Aragua state, Venezuela

Abundance and diversity of Scelionidae was determined in three plots of cacao ( Theobroma cacao ), subjected to three different types of cultural management, at the localities of Choron\ued, Cuyagua and Cumboto. The sampling methods were: pan traps, interception traps, Malaise and sweeps. The samples were taken during the dry season (dry, beginning of the wet season, wet season, and end of the wet season, in 1999. The traps operated one week, and 250 sweeps were made in each plot byseason. A total of 14577 specimens of 183 morphospecies belonging to 39 genera were collected. Telenomus Haliday species can not be properly separated, and hence were not included in the analysis. Greatest abundance was found at Cuyagua (6 124 specimens), highest richness and diversity at Cumboto (166 species; \u3b1= 30,8). Interception traps caught 6594 specimens and yellow pan traps 5134 specimens; richness and diversity were similar with both methods (\u3b1=26,4 y \u3b1=25,8 respectively). Intensity of cultural practices and climatic season did not affect captures. Telenomus was the most abundant genus (5464 specimens). Other important genera were: Idris(1241 specimens and 47 species); Cremastobaeus (1065 specimens, 3 species); Trimorus (629 specimens, 18 species); Gryon (440 specimens, 17 species).Se determin\uf3 la abundancia y diversidad de los Scelionidae (Hymenoptera), en tres parcelas de cacao ( Theobroma cacao ), con tres niveles de manejo agron\uf3mico, en cada una de las siguientes localidades del Estado Aragua: Choron\ued, Cuyagua y Cumboto. Los m\ue9todos de captura fueron: trampas amarillas, interceptaci\uf3n, Malaise y barrido con malla entomol\uf3gica. Los muestreos se efectuaron en las \ue9pocas seca, entrada de lluvias, lluvias, y salida de lluvias del a\uf1o 1999; las trampas operaron durante una semana en cada una de las \ue9pocas; el barrido consisti\uf3 en 250 pases de malla por parcela y por \ue9poca. En total se colectaron 14577 ejemplares, pertenecientes a 39 g\ue9neros y 183 morfoespecies, sin tomar en consideraci\uf3n las morfoespecies del g\ue9nero Telenomus Haliday. La mayor abundancia se obtuvo en Cuyagua (6124 ejemplares), mientras que la mayor riqueza de morfoespecies (166 morfoespecies) y la mayor diversidad (\u3b1= 30,8) se present\uf3 en Cumboto. La mayor abundancia se obtuvo con las trampas de interceptaci\uf3n (6594 ejemplares), en segundo lugar las trampas amarillas (5134 ejemplares). La riqueza y diversidad fue similar en las dos trampas (\u3b1=26,4 y \u3b1=25,8 respectivamente). El nivel de manejo agron\uf3mico, y las \ue9pocas del a\uf1o no influenciaron las capturas. El g\ue9nero m\ue1s abundante fue Telenomus (5464 ejemplares). Otros g\ue9neros importantes en la captura fueron: Idris(1241 ejemplares, 47 morfoespecies); Cremastobaeus (1065 ejem., 3 esp.); Trimorus (629 ejem., 18 esp.); Gryon (440 ejem. 17 esp.)

Expression of RNA polymerase IV and V in Oryza sativa

Abstract RNA polymerase IV and V are principal players in the RdDM pathway, where their current study has shown interaction of several factors that control DNA silencing of intergenic regions and siRNA production. DNA silencing is an important process during cell differentiation, nuclear structure and viral control. However, RNA pol IV and V are yet to be study in model monocot systems like Oryza sativa that can provide further information on genetic silence mechanism in plats. We show the expression pattern of these polymerases in tissues extracts of Oryza sativa. Detectable amounts of these polymerases are found in specific adult plant tissues and particularly expressed during somatic embryogenesis but not during early stages of normal embryo development. The use of synthetic auxin leads to an induction of both RNA pol IV and V in scutellum tissue where nuclear localization may be required for genome reorganization and gene silencing

Scaling-up batch conditions for efficient sucrose hydrolysis catalyzed by an immobilized recombinant Pichia pastoris cells in a stirrer tank reactor

Background: Invert sugar is used greatly in food and pharmaceutical industries. This paper describes scaling-up batch conditions for sucrose inversion catalyzed by the recombinant Pichia pastoris BfrA4X whole cells expressing Thermotoga maritima invertase entrapped in calcium alginate beads. For the first time, we describe the application of a kinetic model to predict the fractional conversion expected during sucrose hydrolysis reaction in both, a model and a prototype bioreactor with 0.5- and 5-L working volume, respectively. Results: Different scaled-up criteria used to operate the 0.5-L bioreactor were analyzed to explore the invert sugar large scale production. After model inversion studies, a 5-L scaled-up reaction system was performed in a 7-L stirred reactor. Both scaled-up criteria, immobilized biocatalyst dosage and stirring speed, were analyzed in each type of bioreactors and the collected data were used to ensure an efficient scale-up of this biocatalyst. Conclusions: To date, there is not enough information to describe the large-scale production of invert sugar using different scaled-up criteria such as dose of immobilized biocatalyst and stirring speed effect on mass transfer. The present study results constitute a valuable tool to successfully carry out this type of high-scale operation for industrial purposes

Modification of the activity of an \u3b1-amylase from Bacillus licheniformis by several surfactants

The influence of different commercial surfactants on the enzymatic activity of a commercial \u3b1-amylase from Bacillus licheniformis (Termamyl 300 L) has been studied. As non-ionic surfactants, alkyl polyglycosides (Glucopon\uae 215, Glucopon\uae 600 and Glucopon\uae 650) were studied, as were fatty alcohol ethoxylates (Findet 1214N/23 and Findet 10/15), and nonyl phenol ethoxylate (Findet 9Q/21.5NF). Also, an anionic surfactant, linear alkyl benzene sulfonate (LAS) was assayed. In general, none of the non-ionic surfactants studied, except Findet 10/15, vary substantially the enzymatic activity. Findet 10/15 has the strongest hydrophobic character and reduces the enzymatic activity more significantly the greater its concentration. Regarding LAS, this surfactant significantly depressed enzymatic activity, presumably due to the electrostatic interactions caused by its anionic character

Plasma lipidome and risk of atrial fibrillation: results from the PREDIMED trial

The potential role of the lipidome in atrial fibrillation (AF) development is still widely unknown. We aimed to assess the association between lipidome profiles of the Prevenci\uf3n con Dieta Mediterr\ue1nea (PREDIMED) trial participants and incidence of AF. We conducted a nested case–control study (512 incident centrally adjudicated AF cases and 735 controls matched by age, sex, and center). Baseline plasma lipids were profiled using a Nexera X2 U-HPLC system coupled to an Exactive Plus orbitrap mass spectrometer. We estimated the association between 216 individual lipids and AF using multivariable conditional logistic regression and adjusted the p values for multiple testing. We also examined the joint association of lipid clusters with AF incidence. Hitherto, we estimated the lipidomics network, used machine learning to select important network-clusters and AF-predictive lipid patterns, and summarized the joint association of these lipid patterns weighted scores. Finally, we addressed the possible interaction by the randomized dietary intervention. Forty-one individual lipids were associated with AF at the nominal level (p < 0.05), but no longer after adjustment for multiple-testing. However, the network-based score identified with a robust data-driven lipid network showed a multivariable-adjusted ORper+1SD of 1.32 (95% confidence interval: 1.16–1.51; p < 0.001). The score included PC plasmalogens and PE plasmalogens, palmitoyl-EA, cholesterol, CE 16:0, PC 36:4;O, and TG 53:3. No interaction with the dietary intervention was found. A multilipid score, primarily made up of plasmalogens, was associated with an increased risk of AF. Future studies are needed to get further insights into the lipidome role on AF. Current Controlled Trials number, ISRCTN35739639

Utilidad de los \ucdndices de Precios, Producci\uf3n y Consumo

La presente investigaci\uf3n centr\uf3 su objetivo principal en estudiar la utilidad de los \ucdndices de Precios, Producci\uf3n y Consumo y su relaci\uf3n con la recaudaci\uf3n del Impuesto al Valor Agregado, a fin de pronosticar el comportamiento de este tipo de impuesto que ayude a la mejor toma de decisiones en la econom\ueda del pa\ueds. El estudio se enmarc\uf3 dentro de tres tipos de investigaci\uf3n, a saber: Documental, por el uso de informes estad\uedsticos y boletines oficiales del Servicio Nacional Integrado de Administraci\uf3n Aduanera y Tributaria y el Banco Central de Venezuela; Descriptivo, a raz\uf3n de describir rasgos y situaciones reales; y Correlacional, por la relaci\uf3n que se realiza entre las variables con la finalidad de establecer el grado de influencia de los \uedndices sobre el impuesto estudiado. Asimismo se lleg\uf3 en esta investigaci\uf3n a las siguientes conclusiones: el Impuesto al Valor Agregado debe ser estudiado en forma interrelacionada con otras variables tributaria y/o econ\uf3micas con la finalidad de analizar de forma m\ue1s id\uf3nea su comportamiento, a tal raz\uf3n se recomienda incorporar otras variables tributarias y econ\uf3micas as\ued como realizar pruebas estad\uedsticas adicionales al modelo propuesto