Ants indirectly reduce the reproductive performance of a leafless shrub by benefiting aphids through predator deterrence

Ant–aphid mutualisms can generate cascade effects on the host plants, but these impacts depend on the ecological context. We studied the consequences of ant–aphid interactions on the reproductive performance of a Mediterranean leafless shrub (Retama sphaerocarpa), through direct and indirect effects on the arthropod community. By manipulating the presence of ants and aphids in the field, we found that ants increased aphid abundance and their persistence on the plant and reduced aphid predators by nearly half. However, the presence of ants did not affect the abundance of other plant herbivores, which were relatively scarce in the studied plants. Aphids, and particularly those tended by ants, had a negative impact on the plant reproductive performance by significantly reducing the number of fruits produced. However, fruit and seed traits were not changed by the presence of aphids or those tended by ants. We show that ants favoured aphids by protecting them from their natural enemies but did not indirectly benefit plants through herbivory suppression, resulting in a net negative impact on the plant reproductive performance. Our study suggests that the benefits obtained by plants from hosting ant–aphid mutualisms are dependent on the arthropod community and plant traitsWe would like to thank J. Seoane and F.M. Azcarate for their comments and suggestions, N. Perez and F.M. Azcarate for identifying aphids and ants, respectively, J. Herranz for helping in the identification of other arthropods and M. Silvestre for her contribution in the fieldwork. We appreciate the comments and suggestions made by two anonymous reviewers. PO was granted with an aid for postgraduate students of the Universidad Autonoma de Madrid. This paper is a contribution to the Project CGL2014-53789-R funded by the Spanish MICINN and the REMEDINAL 3 network (S2013/mae-2719) of the Comunidad de Madrid-European Social Fund

Lipid Involvement in Viral Infections: Present and Future Perspectives for the Design of Antiviral Strategies

Optical physic

West Nile Virus Replication Requires Fatty Acid Synthesis but Is Independent on Phosphatidylinositol-4-Phosphate Lipids

West Nile virus (WNV) is a neurovirulent mosquito-borne flavivirus, which main natural hosts are birds but it also infects equines and humans, among other mammals. As in the case of other plus-stranded RNA viruses, WNV replication is associated to intracellular membrane rearrangements. Based on results obtained with a variety of viruses, different cellular processes have been shown to play important roles on these membrane rearrangements for efficient viral replication. As these processes are related to lipid metabolism, fatty acid synthesis, as well as generation of a specific lipid microenvironment enriched in phosphatidylinositol-4-phosphate (PI4P), has been associated to it in other viral models. In this study, intracellular membrane rearrangements following infection with a highly neurovirulent strain of WNV were addressed by means of electron and confocal microscopy. Infection of WNV, and specifically viral RNA replication, were dependent on fatty acid synthesis, as revealed by the inhibitory effect of cerulenin and C75, two pharmacological inhibitors of fatty acid synthase, a key enzyme of this process. However, WNV infection did not induce redistribution of PI4P lipids, and PI4P did not localize at viral replication complex. Even more, WNV multiplication was not inhibited by the use of the phosphatidylinositol-4-kinase inhibitor PIK93, while infection by the enterovirus Coxsackievirus B5 was reduced. Similar features were found when infection by other flavivirus, the Usutu virus (USUV), was analyzed. These features of WNV replication could help to design specific antiviral approaches against WNV and other related flaviviruses

The nuclear receptor LXRα controls the functional specialization of splenic macrophages.

Macrophages are professional phagocytic cells that orchestrate innate immune responses and have considerable phenotypic diversity at different anatomical locations. However, the mechanisms that control the heterogeneity of tissue macrophages are not well characterized. Here we found that the nuclear receptor LXRα was essential for the differentiation of macrophages in the marginal zone (MZ) of the spleen. LXR-deficient mice were defective in the generation of MZ and metallophilic macrophages, which resulted in abnormal responses to blood-borne antigens. Myeloid-specific expression of LXRα or adoptive transfer of wild-type monocytes restored the MZ microenvironment in LXRα-deficient mice. Our results demonstrate that signaling via LXRα in myeloid cells is crucial for the generation of splenic MZ macrophages and identify an unprecedented role for a nuclear receptor in the generation of specialized macrophage subsets

A Low-Cost Trap to Monitor Parasitism of Macadamia Felted Coccid (Hemiptera: Eriococcidae) and Other Scale Insects

We designed and tested a custom-made parasitoid emergence trap that can be installed on macadamia trees in the field to study parasitism of macadamia felted coccid, Acanthococcus ironsidei (Williams) (Hemiptera: Eriococcidae). The cost of materials for the trap is approximately $3.00 each, and a trap can be constructed in ~15 min. Optimal methods for determining percent parasitism using these traps are still under development, but two proposed methods gave estimates of 0.24 and 4.85% for mortality due to parasitism by Encarsia lounsburyi (Hymenoptera: Aphelinidae). The trap could be an effective and low-cost tool for future parasitism studies or in determining population structure of macadamia felted coccid as it captures parasitoids and other mobile, positively phototactic insects that are present under the covered area of the trap

Un Entorno de Modelado Inteligente y Simulación Distribuida de Plantas de Proceso

[ES] Se describen un conjunto de aplicaciones informáticas que abordan diferentes aspectos del modelado y simulación de procesos continuos. Primero, se presenta un prototipo universitario SIMPD, que es un generador de código de simulación de sistemas de la industria de proceso y cuyo algoritmo básico trata de emular el modo de razonamiento de un experto en modelado cuando escribe un modelo de simulación. Se compara con otros enfoques y se analizan tanto las ventajas que presenta desde la perspectiva del usuario final como los inconvenientes para el programador que trate de aumentar el conjunto de sistemas modelables. Segundo, se describe tanto una arquitectura de simulación distribuida cuyas comunicaciones se basan en el estándar de facto OPC (OLE for Process Control) como el conjunto de herramientas informáticas desarrolladas para diseñar estos escenarios de simulación. Esta arquitectura se aplica a un proceso industrial, explicando el criterio usado para dividir el modelo de simulación global.Los autores quieren agradecer el soporte financiero de la empresa Ebro Agrícolas así como a la Junta de Castilla y León por medio del proyecto “Desarrollo de un entorno de modelado inteligente y simulación distribuida de plantas de proceso”.Acebes, L.; Alves, R.; Merino, A.; De Prada, C. (2010). Un Entorno de Modelado Inteligente y Simulación Distribuida de Plantas de Proceso. Revista Iberoamericana de Automática e Informática industrial. 1(2):42-48. http://hdl.handle.net/10251/146626OJS42481

Melvin Calvin (1911-1997): un Premio Nobel de Química que revolucionó la fisiología vegetal

Artículo dedicado a la memoria de Melvin Calvin, premio Nobel de química en 1961, con ocasión del primer centenario de su nacimiento (2011