Beware the mulch! Adaptation to its natural habitat makes Aspergillus fumigatus a formidable human pathogen.
The fungus Aspergillus fumigatus can be found in decaying organic matter such as compost. As an adaptable environmental microbe it can survive in a wide range of habitats including the lungs of birds and mammals. It has become the most important cause of morbidity and mortality in immunosuppressed patients undergoing stem cell transplantation. The success of A. fumigatus as a pathogen can be attributed to its ability to cope with environmental stresses that are similar to the conditions encountered by microbes in the human body. In particular the fungus can survive interactions with host immune cells such as dendritic cells. In this talk the interaction of the fungus with human dendritic cells will be explored along with the usefulness of protozoan models to examine the pathogenicity of A. fumigatus.
The distribution of Phytophthora in the Greater Blue Mountains WHA.
Disease caused by Phytophthora cinnamomi is becoming increasingly prevalent within the Greater Blue Mountains World Heritage Area (GBMWHA), yet little is known of the distribution of pathogens or the impact of disease. An understanding of the disease distribution is required to develop management strategies in natural ecosystems like the GBMWHA. However where only sporadic information is available, conservation efforts may be limited by incomplete sampling for pathogen presences due to remoteness and inaccessibility of many sites. Risk models can overcome some of these drawbacks. Hence, we modelled the distribution of P. cinnamomi in the GBMWHA by combining landscape and environmental information using a GIS approach. Data layers were reclassified into risk layers using FUZZY logic such that localities conducive to dieback were given the highest risk rating enabling the compilations of a relative risk surface. The area identified with the highest risk was the Blue Mountains National Park primarily due to optimal temperatures for pathogen development, known infestations and an abundance of roads, tracks and paths To investigate the range of Phytophthora infestation soil sampling was conducted based on the risk levels in the model using a stratified random approach. Results indicate the pathogen is widespread across the WHA. However, infestation is sporadic with negative samples occurring frequently. Isolations were more common in areas of greater human activity, such as the highly visited Blue Mountains National Park. Results also implicate vehicles in anthropogenic dispersal. Further testing is being undertaken to improve our understanding of the pathogen-environment-disturbance relationship and genetic analysis of isolates will explore inter and intraspecific species variation. Information gained from the survey will allow managers to prioritise hygiene and quarantine measures, and facilitate the development of ecological models of the distribution of Phytophthora within the GBMWHA.
What is the substrate of the sMMO-like genes of Mycobacterium strain NBB4?
Monooxygenase (MO) enzymes are important for biogeochemistry, biocatalysis and bioremediation. In microbes, MOs are best known as the catalysts for methane oxidation, which is a process of immense importance for the global carbon cycle and for influencing climate change. Mycobacterium strain NBB4, an ethene-oxidising isolate from estuarine sediment, contains a diverse array of MO genes, including homologs of the particulate and soluble methane MOs (pMMO/sMMO), cytochrome p450's, and an ethene MO. We have previously shown that NBB4 can biodegrade several chlorinated pollutants, and that the pMMO homolog is actually an ethane/propane/butane MO. The function of the sMMO homolog in NBB4 (genes designated smoXYBCZ) is currently unknown. This gene cluster has only low identity to sMMO, and methane is not a substrate for growth of NBB4. The aim of this Honours project is to identify the substrate of this novel MO via knockout and heterologous expression experiments. Our hypothesis is that smoXYBCZ acts in the second step of the butane oxidation pathway to convert butanol to butanediol.
News to hand, we've just been informed that 2509 primary school and 2208 highschool students visited the JAMS exhibition during Science Unleashed. Add this to the 500 members of the public that dropped by on the family day and we have a grand total JAMS booth audience over 5000 people. The microbes should be very happy to get such attention!
A big thank you to all the volunteers who manned the JAMS exhibition booth at Science Unleashed over the last two weeks. In my humble opinion JAMS put together an exhibition booth that was about as engaging as an exhibition booth can get. Extra special thanks to Cathy Burke for organising the schedule. Top job! And finally the biggest thanks go to Michael Kertesz for pulling together the exhibition content. Hard to imagine it being done better. The booth was jam packed with interesting stories, ideas and seeds for future careers. We'll be at it again next year for sure. If you have ideas fresh in your mind for adding to the experience, send me an email
Mike Manefield (email@example.com)
Prepared by Valentina Wong (UNSW PhD student)
On a cold Tuesday night, Adrian Low from University of New South Wales warmed the JAMS audience with his passion on bioremediation of organochlorine contaminated groundwater. Adrian described the discovery of Australia’s first 1,2-dichloroethane (DCA) degrading consortium, AusDCA. His work in the field demonstrated the efficacy and sustainability of using organochlorine respiring bacteria to remediate organochlorine contaminants in situ. He plans to isolate the bacterial species responsible for performing this unique task.
JAMS Monthly Meeting Report 29th August 2012
Prepared by Mike Manefield
Though faced with a depleted audience owing to strong attendance of JAMS members at the 14th International Symposium on Microbial Ecology in Copenhagen, Denmark, speakers Dr Oliver Morton, Ms Jazmin Oszvar and Ms Zoe-Joy Newby gave three entertaining and informative presentations with JAMS trademark diversity of subject.
Oliver kicked off with confessions of a clinical microbiologist in his presentation entitled ‘Beware the mulch! Adaptation to its natural habitat makes Aspergillus fumigatus a formidable human pathogen’. The presentation illustrated violent interactions between germinating Aspergillus spores and human dendritic cells including a stunning transcriptomics analysis of the response of Aspergillus fumigatus to the presence of human immature dendritic cells over time.