Analysis of the humoral immune response against total and recombinant antigens of Leishmania infantum: correlation with disease progression in canine experimental leishmaniasis

Leishmaniasis by Leishmania infantum in the Mediterranean Basin constitutes an important problem in both human and veterinary medicine. Based in both the importance of canids as reservoirs for the human disease and the fact that the canine disease may be an excellent model for the human condition, the present work has been conducted to analyze clinical and immune mechanisms associated with canine experimental leishmaniasis. Six-month-old mixed-breed dogs were intravenously infected with L. infantum promastigotes and the infection course was monitored along a 343 days-period. On day 75 post-infection (p.i.), amastigotes were observed in the lymph nodes of all dogs. The analysis of the humoral response against total L. infantum antigens by both ELISA and Western blotting evidenced a correlation between the levels of IgG isotypes (IgG1 and IgG2) and disease progression. It was observed that in those animals showing either a regressive or an oligosymptomatic form of the disease, the anti-Leishmania IgG1 antibodies were undetectable whereas those animals developing active disease showed high levels of anti-Leishmania IgG1 antibodies. Additionally, the time-course of antibody production against L. infantum recombinant antigens in the experimentally infected dogs has been analyzed. The present data suggest that reactivity against the heat-shock protein 70 (HSP70) may be used as diagnostic marker of early steps of infection, and that the appearance of anti-histone antibodies is associated with progression of infection to disease status.     

Design and validation of a wireless sensor network architecture for precision horticulture applications

This paper proposes a general wireless sensor network architecture for monitoring horticultural crops that are distributed among small plots scattered at distances of up to 10 km from one another. The technology used for the real implementation of the architecture is based on the B-MAC (Berkeley Medium Access Control) medium access protocol to assure a high degree of sensor node power autonomy. To resolve this issue, a series of specialized sensor nodes (Soil-Mote, Environmental-Mote and Water-Mote) have been developed along with a gateway to interconnect them with the farm central offices. Before starting device development, simulations were conducted to ensure that acceptable performance would be achieved with the selected technology in terms of node autonomy, achieved throughput and delays. To that end, it was necessary to implement the selected B-MAC protocol in the ns-2 (Network Simulator-2) simulation framework. The final system was deployed on a real crop to check and validate the simulation results against experimental results.     

Behavioral switching in Magellanic woodpeckers reveals perception of habitat quality at different spatial scales

Context

The switching pattern between behavioral modes provides a mechanistic basis for understanding how animals perceive and memorize the habitat quality in their home ranges.

Objectives

We assessed if Magellanic woodpeckers (Campephilus magellanicus) move based on habitat quality at local (neighboring trees) and home range scales.

Methods

We used state-space models to examine the relationship between remotely-sensed estimates of habitat quality (tree decay) and movement of adult woodpeckers tracked with GPS telemetry in southern Chile.

Results

Woodpeckers spent most time (>?80%) in the area-restricted search (ARS) mode in contrast to the exploratory transient mode, characterized by frequent directional displacements (>?50 m). The extent to which individuals switched between behavioral modes was related to habitat quality at different scales. Woodpeckers switched to and remained in the ARS mode when encountering moderate levels of heterogeneity in habitat quality. At very low or high heterogeneity levels, however, individuals switched to and remained in the transient mode, respectively. Likewise, as habitat quality declined locally and across home range, woodpeckers were more likely to adopt a transient mode.

Conclusions

Although woodpeckers seemed to easily perceive and memorize habitat quality at different spatial scales, our results suggest that spatial memory will less effective under extreme levels of habitat heterogeneity.

     

Development and application of a liquid chromatography-mass spectrometry method to evaluate the glyphosate and aminomethylphosphonic acid dissipation in maize plants after foliar treatment

A simple and fast method has been developed and validated to measure glyphosate (GLYP) and aminomethylphosphonic acid (AMPA), which were previously derivatized with 9-fluorenylmethylchloroformate (FMOC-Cl), in maize plants using liquid chromatography (LC) coupled to fluorescence (FLD) and electrospray ionization mass spectrometry (ESI-MS) detection. The method has shown to be consistent, reliable, precise, and efficient. Moreover, the limits of detection (LOD) and quantification (LOQ) reached with the proposed method for GLYP and AMPA are lower than the established maximum residue levels (MRLs). The validated method was applied to quantify GLYP and AMPA in genetically modified (GM) maize foliar treated with the herbicide. It has been found that the GLYP dissipation was mainly due to the progressive dilution effect after herbicide treatment. Finally, it was also observed that the GLYP residue dissipation trend in maize shoot (leaves and stem) tissue determined by LC-ESI-MS matched that determined by liquid scintillation.