London, UK – Scientists have cracked the genetic code of a fungus responsible for some deadly infections and allergic reactions.
Aspergillus fumigatus, which has been shown to be a great health risk. Researchers at the Institute for Genomic Research hope their work could lead to better diagnostic tests, and treatments for fungal infections. Their international collaboration is reported in the journal Nature.
This study does for the first time start to give an indication of why such closely related species in nature can have such different effects. Experts believe that A. fumigatus has become an increasing threat in recent years as more people are suffering the effects of water damaged buildings. Chaetomium and stachybotrys have been linked to neurological conditions from long term exposure, Aspergillus fumigatus has been proven to be the most common cause of invasive aspergillosis and suppressing the human cellular immune response.
The fungus also appears to trigger asthma in some people with particularly sensitive immune systems. But it must be known that this fungus also produces mycotoxins which can cause permanent pathological and immunological damage.
It is unusual because it can thrive at a wide range of temperatures, from 70C – the temperature in a compost heap – to 37C, inside the human body. By altering ambient temperatures in the lab, scientists were able to track how different genes were turned on and off as the environment warmed.
The researchers, including scientists from the UK’s Wellcome Trust Sanger Institute, discovered that the genome of the fungus is made up of eight chromosomes bearing a total of almost 10,000 genes. They found 700 genes that were either significantly different, or did not occur at all in a similar, but less infectious, fungus, Neosartorya fischeri. They also identified for the first time nine allergy-causing substances produced by the fungus, although the toxins should be researched more.
The researchers are now searching these unique genes for clues to explain why A. fumigatus is so infectious. The key genes are likely to play a complex role in the control of many aspects of the way the fungal cells break down and construct chemicals.
The plan is to systematically ‘knock out’, or disable, genes to find out their individual effects. Lead researcher Dr. William Nierman said: “This genome sequence is going to be central for developing tools for effectively managing A. fumigatus infections as they become more prevalent in the aging population.”
Dr. Paul Dyer, an expert in fungi at the University of Nottingham, UK, said: “There is a lot of work ahead, and it is still early days. “But this study does for the first time start to give an indication of why such closely related species in nature can have such different effects.”
Dr. Dyer said A. fumigatus was incredibly abundant in the natural world. It has been estimated that everybody inhales around 200 spores each day. But more importantly, in a water damaged building, dangerous molds can proliferate into much higher numbers, leading to several illnesses, including mycotoxicosis.
More research is needed to find methods of destroying dangerous fungal species. The Mold-Help Organization is currently researching several strategies of eradicating fungal species under specific conditions.