Lymphoid organ cell culture system from Penaeus monodon (Fabricius) as a platform for white spot syndrome virus and shrimp immune-related gene expression

Shrimp cell lines are yet to be reported and this restricts the prospects of investigating the associated viral pathogens, especially white spot syndrome virus (WSSV). In this context, development of primary cell cultures from lymphoid organs was standardized. Poly-l-lysine-coated culture vessels enhanced growth of lymphoid cells, while the application of vertebrate growth factors did not, except insulin-like growth factor-1 (IGF-1). Susceptibility of the lymphoid cells to WSSV was confirmed by immunofluoresence assay using monoclonal antibody against the 28 kDa envelope protein of WSSV. Expression of viral and immunerelated genes in WSSV-infected lymphoid cultures could be demonstrated by RT-PCR. This emphasizes the utility of lymphoid primary cell culture as a platform for research in virus–cell interaction, virus morphogenesis, up and downregulation of shrimp immune-related genes, and also for the discovery of novel drugs to combat WSSV in shrimp culture

Anti–white spot syndrome virus activity of Ceriops tagal aqueous extract in giant tiger shrimp Penaeus monodon

White spot syndrome virus (WSSV), the most contagious pathogen of cultured shrimp, causes mass mortality, leading to huge economic loss to the shrimp industry. The lack of effective therapeutic or prophylactic measures has aggravated the situation, necessitating the development of antiviral agents. With this objective, the antiviral activity in the aqueous extract of a mangrove plant Ceriops tagal in Penaeus monodon was evaluated. The Ceriops tagal aqueous extract (CTAE) was non-toxic to shrimps at 50 mg/ml when injected intramuscularly at a dosage of 10 lL/animal (0.5 mg/animal) and showed a protective effect against WSSV at 30 mg/ml when mixed with WSSV suspension at a 1:1 ratio. When the extract was administered along with the diet and the animals were challenged orally, there was a dose-dependent increase in survival, culminating in 100 % survival at a concentration of 500 mg/kg body weight/day. Neither hypertrophied nuclei nor the viral envelope protein VP28 could be demonstrated in surviving shrimps using histology and indirect immunofluorescence histochemistry (IIFH), respectively. To elucidate the mode of action, the temporal expression of WSSV genes and shrimp immune genes, including antimicrobial peptides, was attempted. None of the viral genes were found to be expressed in shrimps that were fed with the extract and challenged or in those that were administered CTAE-exposed WSSV. The overall results suggest that the aqueous extract from C. tagal can protect P. monodon from white spot syndrome virus infection.

Pathological changes in Fenneropenaeus indicus experimentally infected with white spot virus and virus morphogenesis

To demonstrate pathological changes due to white spot virus infection in Fenneropenaeus indicus, a batch of hatchery bred quarantined animals was experimentally infected with the virus. Organs such as gills, foregut, mid-gut, hindgut, nerve, eye, heart, ovary and integument were examined by light and electron microscopy. Histopathological analyses revealed changes hitherto not reported in F. indicus such as lesions to the internal folding of gut resulted in syncytial mass sloughed off into lumen, thickening of hepatopancreatic connective tissue with vacuolization of tubules and necrosis of rectal pads in hindgut. Virus replication was seen in the crystalline tract region of the compound eye and eosinophilic granules infiltrated from its base. In the gill arch, dilation and disintegration of median blood vessel was observed. In the nervous tissues, encapsulation and subsequent atrophy of hypertrophied nuclei of the neurosecretory cells were found. Transmission electron microscopy showed viral replication and morphogenesis in cells of infected tissue. De novo formed vesicles covered the capsid forming a bilayered envelop opened at one end inside the virogenic stroma. Circular vesicles containing nuclear material was found fused with the envelop. Subsequent thickening of the envelop resulted in the fully formed virus. In this study, a correlation was observed between the stages of viral multiplication and the corresponding pathological changes in the cells during the WSV infection. Accordingly, gill and foregut tissues were found highly infected during the onset of clinical signs itself, and are proposed to be used as the tissues for routine disease diagnosis.

Fenneropenaeus indicus is protected from white spot disease by oral administration of inactivated white spot syndrome virus

Fenneropenaeus indicus could be protected from white spot disease (WSD) caused by white spot syndrome virus (WSSV) using a formalin-inactivated viral preparation (IVP) derived from WSSV-infected shrimp tissue. The lowest test quantity of lyophilized IVP coated onto feed at 0.025 g–1 (dry weight) and administered at a rate of 0.035 g feed g–1 body weight d–1 for 7 consecutive days was sufficient to provide protection from WSD for a short period (10 d after cessation of IVP administration). Shrimp that survived challenges on the 5th and 10th days after cessation of IVP administration survived repeated challenges although they were sometimes positive for the presence of WSSV by a polymerase chain reaction (PCR) assay specific for WSSV. These results suggest that F. indicus can be protected from WSD by simple oral administration of IVP

Acute salinity stress alters the haemolymph metabolic profile of Penaeus monodon and reduces immunocompetence to white spot syndrome virus infection

Influence of acute salinity stress on the immunological and physiological response of Penaeus monodon to white spot syndrome virus (WSSV) infection was analysed. P. monodon maintained at 15‰ were subjected to acute salinity changes to 0‰ and 35‰ in 7 h and then challenged orally with WSSV. Immune variables viz., total haemocyte count, phenol oxidase activity (PO), nitroblue tetrazolium salt (NBT) reduction, alkaline phosphatase activity (ALP), acid phosphatase activity (ACP) and metabolic variables viz., total protein, total carbohydrates, total free amino acids (TFAA), total lipids, glucose and cholesterol were determined soon after salinity change and on post challenge days 2 (PCD2) and 5 (PCD5). Acute salinity change induced an increase in metabolic variables in shrimps at 35‰ except TFAA. Immune variables reduced significantly (Pb0.05) in shrimps subjected to salinity stress with the exception of ALP and PO at 35‰ and the reduction was found to be more at 0‰. Better performance of metabolic and immune variables in general could be observed in shrimps maintained at 15‰ that showed significantly higher post challenge survival following infection compared to those under salinity stress. Stress was found to be higher in shrimps subjected to salinity change to lower level (0‰) than to higher level (35‰) as being evidenced by the better immune response and survival at 35‰. THC (Pb0.001), ALP (Pb0.01) and PO (Pb0.05) that together explained a greater percentage of variability in survival rate, could be proposed as the most potential health indicators in shrimp haemolymph. It can be concluded from the study that acute salinity stress induces alterations in the haemolymph metabolic and immune variables of P. monodon affecting the immunocompetence and increasing susceptibility to WSSV, particularly at low salinity stress conditions

Effects of row spacing on productivity and nodulation of two soybean varieties under hot sub-moist tropical conditions in south-western Ethiopia

The objective of this study was to determine the optimum row spacing to improve the productivity of two soybean (Glycine max L.) varieties under the tropical hot sub-moist agroecological conditions of Ethiopia. A two-year split-plot design experiment was conducted to determine the effect of variety (Awasa-95 [early-maturing], Afgat [medium-maturing]) and row spacing (RS: 20, 25, 30, 35, 40, 45, 50, 55, 60 cm) on the productivity, nodulation and weed infestation of soybean. Seed and total dry matter (TDM) yield per ha and per plant, and weed dry biomass per m^2 were significantly affected by RS. Soybean variety had a significant effect on plant density at harvest and some yield components (plant height, number of seeds/pod, and 1000 seed weight). Generally, seed and TDM yield per ha and per plant were high at 40 cm RS, and weed dry biomass per m^2 was higher for RS >= 40 cm than for narrower RS. However, the results did not demonstrate a consistent pattern along the RS gradient. The medium-maturing variety Afgat experienced higher mortality and ended up with lower final plant density at harvest, but higher plant height, number of seeds per pod and 1000 seed weight than the early-maturing variety Awasa-95. The results indicate that 40 cm RS with 5 cm plant spacing within a row can be used for high productivity and low weed infestation of both soybean varieties in the hot sub-moist tropical environment of south-western Ethiopia.

Utilización de las Webquests y Treasure Hunts en el aula de inglés en combinación con Hot Potatoes.

Resumen basado en la publicación

Educar en imatge, la por : de la rondalla a l'espot publicitari. 'Educar en imagen, el miedo : de la Rondalla al spot publicitario'.

Este artículo quiere justificar la necesidad de analizar la transmisión de la emoción a través del lenguaje, teniendo en cuenta el actual cambio social e individual que suponen los avances tecnológicos. En primer lugar cabe señalar que el cambio al que se hace referencia es el paso de una cultura trasmitida básicamente mediante la palabra y la letra impresa a una cultura trasmitida mediante la imagen. La lengua escrita es desplazada por la icónica. Este cambio en la comunicación entre individuos es también un cambio en la manera de pensar, de ser, de sentir. El artículo se centra en una emoción, el miedo. Se concluye afirmando que los avances tecnológicos proporcionan una nueva percepción del mundo, nuevas emociones y nuevos miedos, y que el lenguaje publicitario es actualmente más eficaz para suscitar emociones a más cantidad de personas que el lenguaje escrito. Se hace referencia especial a las Rondalles Mallorquines, escritas por Mossèn Alcover en el siglo XIX, y el papel que tuvieron para despertar la imaginación y las emociones del niño.

Forecasting the spot prices of various coffee types using linear and non-linear error correction models

Este documento estima modelos lineales y no-lineales de corrección de errores para los precios spot de cuatro tipos de café. En concordancia con las leyes económicas, se encuentra evidencia que cuando los precios están por encima de su nivel de equilibrio, retornan a éste mas lentamente que cuando están por debajo. Esto puede reflejar el hecho que, en el corto plazo, para los países productores de café es mas fácil restringir la oferta para incrementar precios, que incrementarla para reducirlos. Además, se encuentra evidencia que el ajuste es más rápido cuando las desviaciones del equilibrio son mayores. Los pronósticos que se obtienen a partir de los modelos de corrección de errores no lineales y asimétricos considerados en el trabajo, ofrecen una leve mejoría cuando se comparan con los pronósticos que resultan de un modelo de paseo aleatorio.

Suministro de información y seguros de confiabilidad en el mercado SPOT de generación de electricidad colombiano.

Este artículo tiene como objetivo presentar algunos mecanismos de mercado que pueden inducir a mejorar la confiabilidad en el mercado de generación de electricidad spot colombiano; estos son:1) la provisión de información adicional al precio unitario spot, en un mercado que por su naturaleza es aleatorio, y 2) seguros de confiabilidad, al reconocerse que las demandas son altamente inflexibles. También se desarrolla una aplicación para mostrar cómo operarían en la práctica estos mecanismos y se determinan las restricciones que se deben corregir para que sean operativos. Este programa de seguros garantiza una confiabilidad eficiente, provee información importante para los agentes del mercado y reglas de asignación que minimizan los costos económicos en caso de fallas en la capacidad de generación de electricidad, que podrían ser aplicados a mercados de generación de electricidad como el colombiano, donde se han tenido recurrentes crisis de abastecimiento y se ha pensado profundizar en las reformas de este mercado.

TIC y radiografías de hot potatoes.

Se muestran las ventajas didácticas del grupo de seis herramientas gratuitas para profesores, Hot Potatoes, desarrollado por el Centro de Lenguas de la Universidad de Victoria, en Canadá. Asimismo, se explica su manejo y se muestra un ejemplo práctica para desarrollar con la asignatura de Física y Química.

Hot potatoes : aplicaciones educativas.

Curso en formato digital diseñado para personas con conocimientos previos de Windows y de la navegación por Internet, interesadas en conocer las posibilidades docentes del uso de documentos en formato de página Web en las aulas y de generar ejercicios multimedia para visualizar con un navegador.

1001 animals to spot.

El texto y las ilustraciones tienen por objeto ayudar a los niños de primaria a desarrollar habilidades como leer, contar, comparar e identificar. En cada doble página hay escenas de animales en diferentes ecosistemas del mundo, la selva, la montaña, el mar, el bosque, el Polo Norte. Alrededor de los márgenes de las páginas hay una lista de los animales que hay que buscar junto con el número de animales de este tipo que se encuentran en ese lugar. Otro juego se presenta casi al final del libro : En dibujos de Leo hay un grupo adicional de animales que este personaje pinta y el niño debe mirar hacia atrás para localizar las imágenes realizadas por Leo.

Hot and cold.

Se explican las causas de la energía térmica. Se introducen temas como la fricción, las reacciones químicas, la temperatura, el termómetro, las escalas Fahrenheit y Celsius y se explican los conductores, aisladores, y la radiación. Para aprender cómo el Sol calienta la Tierra, la forma en que afecta a nuestro clima, y cómo las plantas y los animales necesitan este calor. Ofrece tres experimentos con explicaciones paso a paso para el aprendizaje por descubrimiento. Los experimentos hacen hincapié en la necesidad del niño de investigar. Hay glosario, bibliografía y direcciones de páginas webs para ampliar información.

Spot goes splash! : and other stories.

Tres historias en las que se narra cómo Spot se divierte con sus amigos bajo la lluvia, va a al parque de atracciones con sus abuelos y, por último, tiene un ajetreado día en casa.