Caspase activation in equine influenza virus induced apoptotic cell death.

Equine influenza virus (EIV) is the leading cause of acute respiratory infection in horses worldwide. In recent years, the precise mechanism by which influenza infection kills host cells is being re-evaluated. In this report, we examined whether caspases, a group of intracellular proteases, are activated following EIV infection and contribute to EIV-mediated cell death. Western blotting analysis indicated that a nuclear target of caspase-3, poly(ADP-ribose) polymerase (PARP) was proteolytically cleaved in EIV-infected MDCK cells, but not in mock-infected cells. In comparison with caspase-3 specific inhibitor Ac-DEVD-CHO, a general caspase inhibitor Boc-D-FMK provided much stronger inhibition of EIV-induced cytopathic effect and apoptosis. Our results suggest that EIV may activate more than one caspase. Caspase activation and cleavage of its cellular targets may play a critical role in EIV-mediated cytotoxicity.     

Recurrent selection in oat for adaptation to diverse environments

In order to test if selection can improve a population's adaptation to diverse environments simultaneously, three cycles of recurrent selection based on grain yield in Iowa, Idaho, and Norway were practiced in an oat (Avena sativaL.) population developed from North American, Scandinavian, and wild species (A. sterilis L.) germplasm sources. Specific objectives were to determine if selection: increased mean yields across environments and within all environments; changed the genetic correlation of yields in different environments; and changed genetic variation for yield within the population. We evaluated 100 to 210 randomly-chosen families from each cycle of selection at three Iowa locations, in Idaho, and in Norway for two years. Grain yield within each location and mean yields across locations increased significantly over cycles of selection. Mean yields across locations expressed as a percent of the original population mean increased at a rate of 2.6% per year. Several families from the third cycle population exhibited both high mean yields across locations and consistently high yields within all locations. Average genetic correlations of yield in different environments were higher in the second cycle than in the original population. A trend of reduced genetic variation and heritability was observed in Iowa only. These results suggest that we successfully improved mean population yield both within and across locations, and yield stability across environments, and in developing families with outstanding adaptation to diverse environments. This revised version was published online in July 2006 with corrections to the Cover Date.     

Droplet Dynamics and Initial Field Tests for Microencapsulated Pesticide Formulations Applied at Ultra Low Volume Using Rotary Atomisers for Control of Locusts and Grasshoppers

The physical properties and field efficacy of microencapsulated acridicides (ME) were investigated to determine their suitability for application at Ultra Low Volume (ULV) rates in Sahelian conditions. Microcapsules were not damaged during application using Micronair AU7000 rotary atomisers. Drop size was dependent upon microcapsule size, smaller microcapsules tending to form dense aggregates within large droplets. The aggregation effect was counteracted by larger microcapsule sizes and by dilution of the concentrated formulation. There was a tendency for microcapsules to land dry at increasing distances from the point of application and at high temperatures and low humidities. In the field in Mali (W. Africa) diluted ME formulations were found to be suitable for ULV application by Berthoud C8 hand-held sprayers, vehicle-mounted Micronair AU7000 pest control kits and helicopter-mounted Beecomist rotary atomisers. ME formulations of fenitrothion, chlorpyriphos and diazinon all suppressed grasshopper populations in annual grassland and were as effective as fenitrothion applied at the standard ULV rate. The spatially heterogeneous and shifting nature of the grasshopper populations prevented the relative efficacy or persistence of the different products to be quantified and the potential for reduced environmental impact could not be tested.