In 2006, the CMBB started a long-term collaborative research program with the J. Craig Venter Institute, USA. This research program applies whole-environment DNA sequencing and functional screening of recombinant libraries in a high-throughput scale to microbial, biofilm communities on marine sponges and algae in Botany Bay, Sydney. These two approaches will give access to the large, microbial diversity that cannot be captured by traditional, culturing-based techniques. The aims of this program are to identify novel bioactives (e.g. novel antifoulants LINK & Quorum Sensing Blockers LINK) and link pyhylogenetic diversity with microbial function in the “unknown and unseen” microbial majority in the marine ecosystem.

Through funding from the US Department of Energy and the Betty and Gordon Moore Foundation several genome sequences of microbial model systems have

been determined and the CMB is currently analysing them for specific biological and ecological aspects. These include:

While surfaces in the marine environment generally become rapidly colonized by microbes followed by the settling of higher organisms, some bacteria can inhibit secondary settlers and prevent build-up of fouling communities. Two model genomes (Pseudoalteromonas tunicata and Roseobacter gallaeciensis) of the "inhibitor group" have been sequenced and analysed for their novel bioactives that kill "fouling" organisms (see also Marine Chemical Ecology and Prokaryote/Eukaryote Interactions & Novel Antifouling Technologies).

 

An emerging theme in marine ecology is the contribution of bacteria to disease and die-off of higher eukaryotes, especially seaweeds. The CMB has identified a potent pathogen that causes bleaching and death of the common red algae, Delisea pulchra. The genome of this novel pathogen has been determined and will give insight into virulence factors that are crucial for disease initiation and progression (see also Marine Chemical Ecology and Prokaryote/Eukaryote Interactions).

 

Microorganisms from natural environments are almost always faced with a limited supply of nutrients. Two strategies are found in microbes living in the marine environment: eat-fast-while-you-can-and-then-rest  (copiotrophic) or scavengewhatever-little-is-around-and-grow-slowly (oligotrophic). Two model genomes for each lifestyle have be sequenced and analysed (Photobacterium angustum and Sphingopyxis alaskensis in collaboration with Rick Cavicchioli, School of Biotechnology and Biomolecular Sciences, UNSW). An understanding of these adaptive responses has important implications for global nutrient and energy cycles.

 

Biofilms have recently been shown to be a major source for the creation of genetic diversity and hence could represent a major step in the evolution of multi-cellularity. In 2007 the CMB received funding from the Australian Cystic Fibrosis Research Trust to apply ultra-high throughput sequencing to characterise the large array of genetic variants produced in biofilm systems to gain new insight into fundamental mechanisms of evolution (see also Biofilms and Bacterial Signalling).

For any queries on this project please contact Dr. Torsten Thomas