Thursday, 29 July 2010

It's A Knockout Gem's Appeal for the Fungal Research Trust

Newly formed charity Gem's Little Gems is holding a fundraising event for the Fungal Research Trust. The appeal has a website and donation page here

Wednesday, 28 July 2010

Detection of Aspergillus indoors - a new type of device

It has been announced in the business media that a US company (Universal Detection Technology) have developed a device that will identify several Aspergillus species and several other fungi by detecting them in the home environment.

There isn't much detail given about this device so far other than it being based on the same technology that the company use in devices intended to detect chemical hazards. Immunochromatography is a commonly used technology when specific proteins need to be detected quickly and reliably by unskilled operators in the home e.g. many pregnancy testing kits use similar technology.
This suggests that samples will have to be taken, extracted into a liquid which can then be run through the device. Most likely a swab of a mouldy area will be washed into a solution and drops of that solution applied to the device.

The manufacturers claim that the device can identify the most harmful species of Aspergillus, Penicillium and Stachybotrys.Up to now this type of information has only been possible to obtain using the services of a specialist company, so it is easy to see that this device could offer a cheaper alternative to that form of testing - though no price for this device is available yet so we don't know how cheap it might be.

If proven to be true this could be a very useful way to identify what fungi are growing in a building, however my first impression is that it won't tell you much about how much of each fungus is present.

These devices are usually very sensitive, which is great when you are trying to detect tiny amounts of protein in a fluid, but we all live in houses that have small amounts of fungi circulating within them and settling on surfaces in the form of spores. This is harmless to most of us, so if this device shows up a positive result for these tiny amounts of fungi it isn't really differentiating between harmful levels of fungi and relatively normal, safe levels of fungi.

Likewise the device is unlikely to be able to indicate whether or not that fungus is producing toxins.The presence of a fungus does not necessarily indicate the presence of a toxin, so again we cannot correlate what this device is telling us with the effect that the fungi might have on our health.

Overall this looks like a potentially useful device, but it may well need a lot of supporting advice to interpret the result effectively.

Friday, 23 July 2010

Your Hay Fever might actually be Allergy to Aspergillus

An article in the national media this week states that the Royal College of Physicians & Royal College of Pathologists in the UK have released a report emphasising the importance of the correct identification of the offending allergens for people who suffer from allergies.

Many sufferers seem to assume that the symptoms that they are experiencing - often pretty miserable symptoms - are hay fever that is an inevitable part of their summer. In fact for many something else is causing the problem;

12 most common inhaled allergens are:
  • grass pollen
  • house dust mite
  • cat
  • stinging nettle pollen
  • hazelnut pollen
  • birch pollen
  • latex
  • mugwort pollen
  • dog
  • moulds
    • Aspergillus fumigatus
      Alternaria alternata
      Cladosporium herbarum

Avoidance of the allergen is a fundamental part of improving the life of a sufferer but all to often the patient has no idea what this is - people who thought that they suffered from hay fever are often in fact suffering from allergies to quite different allergens.

There are now kits available that a person can use to home test some airborne allergens e.g. Imutest. These can be useful as a guide but far more detailed tests would be performed by your doctor.

Monday, 19 July 2010

Vitamin B3 Could Be Used to Treat Aspergillus Infections

Researchers have discovered that vitamin B3 (niacin) has antifungal properties that work against a wide range of fungi including Aspergillus. This is interesting as we already know quite a lot about vitamin B3 and it holds out the prospect of the development of a new antifungal drug family that has far fewer side effects compared with current antifungals drugs.

Even more interestingly vitamin B3 antifungal activity works on strains of the fungus which are resistant to current antifungals - they seem equally as effective against resistant or sensitive strains and this suggests that vitamin B3 works via an entirely different mechanism compared with current antifungal drugs. We mention how important this is in an earlier blog, but to summarise if we can exploit new targets for antifungal activity it should lead to drugs which can treat infections that are resistant to other antifungal drugs, Resistance to current antifungal drugs is something that is an increasing problem in the clinic.

In addition there is the possibility that two drugs that use two different targets for their antifungal activity could be used together and thus have far more effect than either drug when used alone (i.e. combination therapy). Vitamin B3 (or drugs developed from this research) could be a useful addition to this type of therapy.

This is also interesting scientifically as it seems to work through interference with a fungal enzyme that is intimately involved in DNA replication. DNA is closely associated with histone proteins during the cell cycle, effectively packaging it away  during quiet times when the cell is not replicating whilst also enabling efficient, ordered unpackaging and replication of DNA prior to cell division and growth (see cartoon animation of this & other processes here).

We have learned that chemical modification (acetylation) of histone is important for the correct control of the cell cycle however we do not know its precise function. Acetylation and deacetylation of histone is carried out by specific enzymes in the cell nucleus, one of which is a target for vitamin B3. Interference with the mechanism of acetylation of histone (by e.g. treating it with vitamin B3) results in the loss of histone and widespread abnormal growth of the fungus. This gives us a little more insight and another tool to look at how this whole mechanism works.

This mechanism of regulation of histone acetylation in fungi seems to be specific to fungi making it a highly attractive target for antifungal therapy, as interfering with this regulation should not interfere with human cell cycle histones, reducing side effects of any resulting antifungal drugs.

Monday, 12 July 2010

New biopesticide Aflasafe™ may solve Kenya's ongoing maize contamination problem.

A recurring issue for grain farmers in the developing world is the contamination of crops with harmful Aspergillus species which produce aflatoxins (mycotoxins).
Aflatoxin is a silent killer that causes liver cancer and suppresses the immune system. It also retards growth and development in children. People exposed to very high aflatoxin concentrations experience liver failure and rapid death. From 2004 to 2006, nearly 200 unsuspecting people in Kenya died in this manner after eating highly contaminated maize. Aflatoxin is a colorless toxin which is invisible and only laboratory tests can confirm its presence.

In Kenya this year, the contamination of the country's main crop - maize- with aflatoxin, a highly poisonous cancer-causing chemical produced by a fungus scientifically known as Aspergillus flavus, was the result of poor drying and storage of the grain following heavy rainfall near harvest time.

A particular toxigenic strain of Aspergillus flavus is largely responsible for the aflatoxin contamination of the crops. But there is a novel way to control contamination using a biological control approach. Experts have identified a locally occurring non-toxic strain of the fungus. This strain can be introduced to the crops prior to harvesting and will safely outcompete and virtually eliminate the toxic aflatoxin producing strain, effectively reducing contamination of the maize grains in fields.

A single application of this "biopesticide" AflasafeTM 2-3 weeks before maize flowering is sufficient to prevent aflatoxin contamination throughout the season and even during grain storage. Note this is not a chemically derived pesticide - but the use of naturally occurring strains of A.flavus to swamp the toxic strains.
Trials in the US have shown that biocontrol in this way has successfuly reduced contamination and in Nigeria provisional registration and use of Aflasafe™ in 2009 allowed farmers to reduce aflatoxin contamination of their crops by 80%.
Research has shown that Aflasafe™ treatments provide long-term benefits and that Aflasafe™ may not need to be applied every year.

Africa-based International Institute of Tropical Agriculture, in partnership with the Nigerian government and the United Nations Industrial Development Organization (UNIDO), is working on obtaining full registration and identifying an entity that would mass manufacture, market, and distribute Aflasafe™ in Nigeria to save the health and income of millions of families.

The researchers are now calling upon the government and the private sector in Kenya to partner with them and make this biocontrol option available to the farmers to save their essential harvests from future aflatoxin contamination.
Source Science Letter July 1st, (2010)

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