Use of pyrethroid analogues to identify key structural features for enhanced esterase resistance in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

It has been reported previously that the major resistance mechanism to pyrethroid insecticides by the cotton bollworm Helicoverpa armigera (Hübner) in Australia is a consequence of overproduction of esterase isoenzymes. This paper reports structure-activity relationships that support such a view, based on in vivo bioassays conducted with a range of pyrethroid structures containing a variety of acid and alcohol moieties and the correlation with in vitro esterase inhibition assays against the same structures, and identifies the critical regions of the molecule with regard to esterase inhibition, and hence resistance. The implications of this work in terms of possible resistance management are evaluated and discussed.     

PROGRESS ON IMPROVING AGRICULTURAL NITROGEN USE EFFICIENCY: UK-CHINA VIRTUAL JOINT CENTERS ON NITROGEN AGRONOM

● Virtual joint centers on N agronomy were established between UK and China. ● Key themes were improving NUE for fertilizers, utilizing livestock manures, and soil health. ● Improved management practices and technologies were identified and assessed. ● Fertilizer emissions and improved manure management are key targets for mitigation. Two virtual joint centers for nitrogen agronomy were established between the UK and China to facilitate collaborative research aimed at improving nitrogen use efficiency (NUE) in agricultural production systems and reducing losses of reactive N to the environment. Major focus areas were improving fertilizer NUE, use of livestock manures, soil health, and policy development and knowledge exchange. Improvements to fertilizer NUE included attention to application rate in the context of yield potential and economic considerations and the potential of improved practices including enhanced efficiency fertilizers, plastic film mulching and cropping design. Improved utilization of livestock manures requires knowledge of the available nutrient content, appropriate manure processing technologies and integrated nutrient management practices. Soil carbon, acidification and biodiversity were considered as important aspects of soil health. Both centers identified a range of potential actions that could be taken to improve N management, and the research conducted has highlighted the importance of developing a systems-level approach to assessing improvement in the overall efficiency of N management and avoiding unintended secondary effects from individual interventions. Within this context, the management of fertilizer emissions and livestock manure at the farm and regional scales appear to be particularly important targets for mitigation.     

Effects of changing temperature on benthic marine life in Britain and Ireland

• 1. The coastal waters surrounding Britain and Ireland became warmer during the 20th century and, according to the UK Climate Impact Programme 2002 scenarios of change and other sources, average annual seawater temperatures may rise a further 2°C or more by the 2050s. This warming is part of a global rise in sea‐ and air‐surface temperatures that will cause changes in the distribution and abundance of species.
• 2. Initially, there will not be a wholesale movement northwards of southern species or retreat northwards of northern species, because many additional factors will influence the responses of the different organisms. Such factors include the hydrodynamic characteristics of water masses, the presence of hydrographical and geographical barriers to spread and the life history characteristics (reproductive mode, dispersal capability and longevity) of species. Survey data over the past century show how organisms react to changes of the order of 0.5°C, and in the last two decades, when sea temperatures have risen by as much as 1°C, there have been significant local changes in the distribution of intertidal organisms. These past changes provide a clue to more extensive changes expected in the future if global warming develops as predicted.
• 3. Where species affected by climate change are dominant or key structural or functional species in biotopes, there may be a change in the extent and distribution of those biotopes. Some, dominated by predominantly northern species such as the horse mussel Modiolus modiolus, may decline and reduce their value as rich habitats for marine life. Others, characterized by southern species, for example the sea fan Eunicella verrucosa and the alcyonacean Alcyonium glomeratum, may increase in extent.
• 4. Using information on the life history characteristics of species, their present distribution and other factors, a key supported by a decision tree has been constructed to identify ‘types’ of organism according to their likely response to temperature rise. Conspicuous and easily identified rocky substratum species are good candidates to track change. Using the key, many species are shown as likely to increase their range northwards significantly. In contrast, fewer will decline in abundance and extent in the north. If, as anticipated, global warming continues, then species with distributions already accurately mapped, or being mapped at present, will provide baseline data to test forecasts.

Copyright © 2004 John Wiley & Sons, Ltd.     

The antimicrobial activity of honey against common equine wound bacterial isolates

Delayed healing associated with distal limb wounds is a particular problem in equine clinical practice. Recent studies in human beings and other species have demonstrated the beneficial wound healing properties of honey, and medical grade honey dressings are available commercially in equine practice. Equine clinicians are reported to source other non-medical grade honeys for the same purpose. This study aimed to assess the antimicrobial activity of a number of honey types against common equine wound bacterial pathogens. Twenty-nine honey products were sourced, including gamma-irradiated and non-irradiated commercial medical grade honeys, supermarket honeys, and honeys from local beekeepers. To exclude contaminated honeys from the project, all honeys were cultured aerobically for evidence of bacterial contamination. Aerobic bacteria or fungi were recovered from 18 products. The antimicrobial activity of the remaining 11 products was assessed against 10 wound bacteria, recovered from the wounds of horses, including methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa. Eight products were effective against all 10 bacterial isolates at concentrations varying from <2% to 16% (v/v). Overall, the Scottish Heather Honey was the best performing product, and inhibited the growth of all 10 bacterial isolates at concentrations ranging from <2% to 6% (v/v).Although Manuka has been the most studied honey to date, other sources may have valuable antimicrobial properties. Since some honeys were found to be contaminated with aerobic bacteria or fungi, non-sterile honeys may not be suitable for wound treatment. Further assessment of gamma-irradiated honeys from the best performing honeys would be useful.     

A rapid immunoperoxidase-based virus neutralization assay for salmonid alphavirus used for a serological survey in Northern Ireland

A modified virus neutralization (VN) assay was developed to replace an existing assay read on the presence or absence of virus-induced cytopathic effect (CPE). The modified assay used a monoclonal antibody to salmon pancreas disease virus as the first layer of an immunoperoxidase (IPX)-based immunostaining technique to detect viral growth. The IPX-based VN assay required only 3 days to perform, and the adoption of a 96-well microtitre format facilitated a high throughput of samples requiring small volumes of serum, cells and virus. When 352 sera from farmed salmon and 302 sera from farmed trout were tested by both the modified and the original CPE-based assays, overall correlations of 97.72 and 96.03% were, respectively, obtained (96.94% combined). When the modified assay was used to test 188 sera collected from wild salmonids in freshwater river systems in Northern Ireland, no positive results were recorded.