@*@ Header
Aspergillus fumigatus fungus. Canadian researchers have discovered the defence mechanism of the often deadly fungus and are developing ways to fight it  by using its own defences against it.

Aspergillus fumigatus fungus. Canadian researchers have discovered the defence mechanism of the often deadly fungus and are developing ways to fight it by using its own defences against it.
Photo Credit: handout MUHC

Canadian breakthrough against a deadly fungus

FacebookTwitterGoogle+PinterestWeChatEmailPrintPartager

Most of the time when we hear about sickness, we think of bacterial infections, but moulds, or fungi can also be killers.  There are  about 1.5 million species of fungus, some of which are deadly, and some which can become deadly given the right circumstances.

One common one called Aspergillus fumigatus, (AF) can cause serious infection- aspergillosis- and very often death in over a million people a year.

Why and how this particular fungus becomes so virulent and so hard to treat once it takes hold, has been a question stumping scientists. Now Canadian researchers have answered those questions.

Teams in Toronto and Montreal conducted the research. The research supervisor in Montreal is Dr. Donald Sheppard. He is a professor of medicine, microbiology and immunology  and Director of the Division of Infectious Diseases at  McGill University, Montreal, and a researcher at the Research Institute of the McGill University Health Centre (RI-MUHC)

Listen
Dr. Donald Sheppard is a microbiology professor and Director of the Division of Infectious Diseases at the Research Institute of the McGill University Health Centre (RI-MUHC)
Dr. Donald Sheppard is a microbiology professor and Director of the Division of Infectious Diseases at McGill University, and a researcher at the Research Institute of the McGill University Health Centre (RI-MUHC) © MUHC

We are breathing in millions of mould spores and bacteria every day, yet thanks to our immune system we never notice them.

As Dr Sheppard says, our immune system takes care of almost all such threats before they can do any harm. However, when that immune system is compromised, through chronic disease, such as cystic fibrosis or  heavy medical therapies such as chemotherapy against cancer,  Aspergillus fumigatus  can take hold, causing greatly increased concern about survival. In fact the majority of fungal infections are due to this particular mould, which is hard to eradicate.

Indeed even with currently available antifungal treatments, the mortality

of invasive aspergillosis remains over 50%

Dr. Sheppard says what their research has discovered is that our bodies defences such as the white blood cells or “neutrophils” are thwarted by a unique coating on this particular fungus which acts like an armoured defence.

The cover of this week's Jounral of Biological Chemistry features the Canadian research and shows the enzyme breaking through the GAG defence of AF
The cover of this week’s Jounral of Biological Chemistry features the Canadian research and shows the enzyme breaking through the GAG defence of AF ©  JBC

It prevents both the immune defences and anti-fungal drugs from getting through to Aspergillus to kill it. The researchers discovered sugary polysaccharide (galactosaminogalactan (GAG), which forms the protective shell along the length of the fungus.

The research was published in two recent scientific journal papers, one in PLOS –Pathogens in October entitled, “The Fungal Exopolysaccharide Galactosaminogalactan Mediates Virulence by Enhancing Resistance to Neutrophil Extracellular Traps  and another this week and featured on the cover as “paper of the week” of the Journal of Biological Chemistry. Vol 290, N0. 46 under the title, “ Sph3 Is a Glycoside Hydrolase Required for the Biosynthesis of Galactosaminogalactan in Aspergillus fumigatus.

The researchers discovered the sugary polysaccharide (galactosaminogalactan (GAG),) and that by manipulating it were able to adjust AF virulence.

Aspergillus fumigatus colony invading lung cells
Aspergillus fumigatus colony invading lung cells © MUHC

They also discovered a particular protein’s role Sph3 in producing GAG, and are now working on using that enzyme to develop ways to turn around the protein to break up the sugary matrix protecting the fungus.

As the protection is weakened by, it would then open up the fungus to attack by natural defence and by anti-fungals.

In a press release by the team at McGill and Toronto’s Hospital for Sick Children, collaborator Dr. P. Lynne Howell (Hospital for Sick Children) wrote

“By using the hydrolases, you essentially chew up the protective matrix around the fungus and therefore reduce the tolerance the fungus has, and so the existing antibiotics we have now become more effective”.  Dr. Howell adds, “What we are currently trying to do is develop this particular enzyme, as well as other hydrolases, essentially for combination therapies where you’d use the hydrolase plus an antibiotic or antifungal.”

Dr. Sheppard’s team feels this could lead to a major breakthrough in potentially saving the lives of vast numbers of victims of aspergillosis.

Tagged with: , , , , , , , ,
Posted in Health, Science and Technology

Do you want to report an error or a typo? Click here!

@*@ Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

 characters available

Note: By submitting your comments, you acknowledge that Radio Canada International has the right to reproduce, broadcast and publicize those comments or any part thereof in any manner whatsoever. Radio Canada International does not endorse any of the views posted. Your comments will be pre-moderated and published if they meet netiquette guidelines.

Netiquette »

When you express your personal opinion in an online forum, you must be as courteous as if you were speaking with someone face-to-face. Insults and personal attacks will not be tolerated. To disagree with an opinion, an idea or an event is one thing, but to show disrespect for other people is quite another. Great minds don’t always think alike—and that’s precisely what makes online dialogue so interesting and valuable.

Netiquette is the set of rules of conduct governing how you should behave when communicating via the Internet. Before you post a message to a blog or forum, it’s important to read and understand these rules. Otherwise, you may be banned from posting.

  1. RCInet.ca’s online forums are not anonymous. Users must register, and give their full name and place of residence, which are displayed alongside each of their comments. RCInet.ca reserves the right not to publish comments if there is any doubt as to the identity of their author.
  2. Assuming the identity of another person with intent to mislead or cause harm is a serious infraction that may result in the offender being banned.
  3. RCInet.ca’s online forums are open to everyone, without regard to age, ethnic origin, religion, gender or sexual orientation.
  4. Comments that are defamatory, hateful, racist, xenophobic, sexist, or that disparage an ethnic origin, religious affiliation or age group will not be published.
  5. In online speak, writing in ALL CAPS is considered yelling, and may be interpreted as aggressive behaviour, which is unpleasant for the people reading. Any message containing one or more words in all caps (except for initialisms and acronyms) will be rejected, as will any message containing one or more words in bold, italic or underlined characters.
  6. Use of vulgar, obscene or objectionable language is prohibited. Forums are public places and your comments could offend some users. People who use inappropriate language will be banned.
  7. Mutual respect is essential among users. Insulting, threatening or harassing another user is prohibited. You can express your disagreement with an idea without attacking anyone.
  8. Exchanging arguments and opposing views is a key component of healthy debate, but it should not turn into a dialogue or private discussion between two users who address each other without regard for the other participants. Messages of this type will not be posted.
  9. Radio Canada International publishes contents in five languages. The language used in the forums has to be the same as the contents we publish. The usage of other languages, with the exception of some words, is forbidden. Messages that are off-topic will not be published.
  10. Making repetitive posts disrupts the flow of discussions and will not be tolerated.
  11. Adding images or any other type of file to comments is forbidden. Including hyperlinks to other websites is allowed, as long as they comply with netiquette. Radio Canada International  is in no way responsible for the content of such sites, however.
  12. Copying and pasting text written by someone else, even if you credit the author, is unacceptable if that text makes up the majority of your comment.
  13. Posting any type of advertising or call to action, in any form, to Radio Canada International  forums is prohibited.
  14. All comments and other types of content are moderated before publication. Radio Canada International  reserves the right to refuse any comment for publication.
  15. Radio Canada International  reserves the right to close a forum at any time, without notice.
  16. Radio Canada International  reserves the right to amend this code of conduct (netiquette) at any time, without notice.
  17. By participating in its online forums, you allow Radio Canada International to publish your comments on the web for an indefinite time. This also implies that these messages will be indexed by Internet search engines.
  18. Radio Canada International has no obligation to remove your messages from the web if one day you request it. We invite you to carefully consider your comments and the consequences of their posting.

*