Monday, 25 January 2010

Controlling insect numbers using fungi

Some insects are a health hazard to humans or are a threat to human food supplies. Controlling the numbers of insects is a high priority and the possibility of using fungi is being investigated.
Aspergillus is a known pathogen of some of these important insects e.g. mosquito, cockroach and locust so it is feasible that judicious use of Aspergillus could be developed into an important weapon against our tiny enemies.

One of the problems to be overcome before Aspergillus could be used in this way is how to safely infect large numbers of insects or their larvae (which live in water). Given that some species of Aspergillus are themselves pathogenic and/or poisonous to humans it wouldn't be a good idea to simply adopt a widespread air dispersal, so alternative options are being considered.

This paper investigates several factors that influence the mortality of insect larvae after treatment with fungal spores and found that the number of larvae killed were dependant of several factors (species of fungus, larval stage of the insect, density of larvae and nutrient availability) but not dependant on concentration of fungal spores applied (due to clumping together of the spores on the surface of the water) or the time of exposure of the insects to the spores. Better methods for ensuring an even spread of spores across the surface of the water the larvae were growing in was called for.

This study on fully grown mosquitoes addresses the need to avoid spraying fungal spores into the air, and instead tries to make progress on how to infect flying insects when they come to rest by coating the surface they land on with spores. Methods that used a particular solvent (Evaporative Shellsol T solvent) and a 'K-bar' stainless steel coating bar was found to be optimal for the purpose of coating paper in such a way that insects landing on the paper were given an effective dose of spores.
The coated paper achieved a consistent result and thus provides a tool that can be used to achieve comparable results between different labs throughout the world.

Monday, 18 January 2010

The Aspergillosis Patients Meeting, Rome 2010

The Fungal Research Trust are holding a meeting designed for people who have aspergillosis or people with an interest in aspergillosis in Rome on 3rd February 2010.

The program consists of the following talks:

How important is Aspergillus in cystic fibrosis?: Rick Moss, Stanford
Aspergillus and CGD: Brahm Segal, Buffalo
Chronic pulmonary aspergillosis: David Denning, Manchester
Why is invasive aspergillosis such a difficult disease to diagnose and treat?: Ben de Pauw, Nijmegen

Steroids, Aspergillus and antifungals: Russell Lewis, Houston
Surgery for aspergilloma and invasive aspergillosis: Gilbert Massard, Strasbourg
Getting antifungal drug levels right - why does it matter?: David Andes, Madison WI
How can I clean up my environment at home?: Malcolm Richardson, Manchester

Full program

Any patients or other interested parties who wish to attend can still register by going to the following link: Registration & Full details of meeting

If you have a question for one of our experts please send us an email and we will try to get you an answer if time allows

Friday, 15 January 2010

Building aflatoxin-resistant crops

Aflatoxin Contamination of Commercial Maize Products during an Outbreak of Acute Aflatoxicosis in Eastern and Central KenyaWe have mentioned in earlier blogs the devastating effects that Aspergillus and its toxins can have on food crops. At best a crop contaminated with aflatoxin is sellable at a reduced price, at worse it is worthless.

Some farmers are seeding their crops with strains of Aspergillus that do not produce aflatoxin and find that that is an effective way to reduce contamination, as the non-toxic strains can outgrown the toxic strains. That approach requires extra time, labour and expense of the farmer - how much better would it be if the plants themselves could be made resistant to contamination by aflatoxins?

It turns out that mutants of a family of genes present in most plants called LOX hold one of the keys to achieving this goal. This group identified LOX genes that when mutated allowed higher levels of aflatoxin contamination (LOX3) and suggests that this information could be used as part of the effort to produce strains of crops that are resistant to mycotoxin accumulation. It tells us that plants are not passive victims of mycotoxin contamination and can influence the outcome themselves - thus avoiding all of the extra work required by current strategies outlined above.

This recent review goes into the subject in much more detail and with a wider viewpoint taking in several gene mutations and more fungal pathogens. LOX gene activity may even mimic similar genes in the fungus that tell the fungus to sporulate and produce toxins, suggesting that the relationship between fungus and plant host is intimate and very complex.

Simplistically is is possible to speculate that growing crop strains  that do not contain genes that turn on mycotoxin production will lead to far lower levels of toxins in the resultant harvest. Before we can do that we need to know what effect that will have on the plant and what other effects that might have - for example it might be that mycotoxins protect the plant or its seed from other infections? After all, the plant is only 'interested' in its own survival rather than providing food for us.

This research is still in its infancy but shows great potential for increasing the efficiency with which we can grow food free of toxins despite the best efforts of our fungal foes.

Wednesday, 6 January 2010

Famous penguin in love triangle, falls ill with aspergillosis




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