July 2013

Event Date: 
Wednesday, July 31, 2013 - 18:00 - 18:15
Institution: 
University of Sydney
Title: 

Genome evolution in Blattabacterium cuenoti

Abstract: 

In addition to harbouring intestinal symbionts, some animal species also possess intracellular symbiotic microbes. The relative contributions of gut-resident and intracellular symbionts to host metabolism, and how they coevolve are not well understood. Cockroaches and the termite Mastotermes darwiniensis present a unique opportunity to examine the evolution of spatially separated symbionts, as they harbour gut symbionts and the intracellular symbiont Blattabacterium cuenoti. The genomes of B.cuenoti from M.darwiniensis and the social wood-feeding cockroach Cryptocercus punctulatus are each missing most of the pathways for the synthesis of essential amino acids found in the genomes of relatives from non-wood-feeding hosts. Hypotheses to explain this pathway degradation include: (i) feeding on microbes present in rotting wood by ancestral hosts; (ii) the evolution of high-fidelity transfer of gut microbes via social behaviour. To test these hypotheses, we sequenced the B.cuenoti genome of a third wood-feeding species, the phylogenetically distant and non-social Panesthia angustipennis.We show that host wood-feeding does not necessarily lead to degradation of essential amino acid synthesis pathways in B.cuenoti, and argue that ancestral high-fidelity transfer of gut microbes best explains their loss in strains from M.darwiniensis and C.punctulatus.
 

Event Date: 
Wednesday, July 31, 2013 - 18:15 - 18:30
Institution: 
University of Technology Sydney
Title: 

The Sydney Harbour microbiome: bacterioplankton diversity and dynamics

Abstract: 

Sydney Harbour and its surrounding coast is an iconic habitat that supports a diverse ecosystem however the composition and dynamics of bacterioplankton in the system remain a major knowledge gap. The harbour and coast also provide a model system for investigating the spatiotemporal distribution of microorganisms across multiple physicochemical gradients and their response to anthropogenic input. Using next-generation DNA sequencing, we provide a comprehensive profile of microbial communities from a range of habitats inside the harbour and show strong biogeographic patterns in taxonomic composition.  Using network analysis to visualize correlations between community structure and environmental variables we have identified the key drivers of community partitioning. Combined these results lead to a more detailed understanding of the diversity and roles of bacterioplankton in Sydney Harbour and its surrounds, and provide insight into marine microbial ecology generally. 

Event Date: 
Wednesday, July 31, 2013 - 19:00 - 19:45
Institution: 
Australian National University
Title: 

Understanding Secondary Metabolite Biosynthesis as the Key to Unlock New Chemical Diversity in Fungi – from Viridicatumtoxin to the Immunosuppressive Neosartoricin

Abstract: 

The advancement of DNA sequencing technology has unlocked an unprecedented amount of microbial genomic information. These genome sequences also revealed a large number of secondary metabolite (SM) genes in both bacteria and fungi. For filamentous fungi in particular, the number of SM gene clusters encoded in the genome are often beyond the number of compounds that are reported for individual species. This is likely attributed to the tight regulation of the SM genes by the eukaryotic fungi compared to their prokaryotic counterparts, where some SM genes are only expressed in the presence of appropriate environmental signals. Research is currently going on to uncover new methods to activate these "silent" gene clusters. However, at the same time, continuously expanding our understanding of the relationship between SM compounds, the biosynthetic genes and microbial ecology will assists us in navigating the exponentially expanding seas of genomic information in the search for new bioactive compounds. The past four years, I have been involved in the elucidation of the SM pathways for viridicatumtoxin, griseofulvin, tryptoquialanine, cytochalasins, lovastatins, echinocandin, fumagilin and azaphilones. A specific example is given here on how the investigation into the genes and enzymes involved in the biosynthesis of an interesting molecule, viridicatumtoxin, eventually leads to the discovery of a new immunosuppressive compound, neosartoricin, from the human pathogens Aspergillus fumigatus and Neosartorya fischeri.

The Australian Museum Science Festival is fast approaching and JAMS Inc is registered to occupy an exhibition booth to introduce thousands of school children to the wonders of microbiology.

Michael Kertesz (USyd) has again agreed to be the scientific content manager of the exhibition but we're still in need of a human resources manager to schedule and advise volunteers for the exhibition. Email Mike Manefield if you're interested in the HR gig or if you're interested in volunteering.

Continue reading for the festival schedule.