March 2012

Event Date: 
Tuesday, April 24, 2012 - 18:00 - 18:15
Institution: 
University of Georgia
Title: 

Bioluminescence: The First 3000 Years

Abstract: 

Bioluminescence along with astronomy, is one of the oldest subjects of scientific investigation.  Light from fireflies is mentioned in ancient Chinese poetry and later more systematic studies are in the writings of Aristotle and Pliny the Elder.  In the modern era, Robert Boyle in a 1672 Proc. Roy. Soc. paper, reported the requirement of bacterial bioluminescence for air, now known to be oxygen.  His paper contained the first published Table of experimental results.  In 1876 Dubois reported that the living light from the bioluminescent clam, could be extracted into solution.  He showed that bioluminescence was just a chemical reaction, an enzyme and substrate, which he dubbed “luciferase” and "luciferine".  In 1947, McElroy reported that Dubois' substrate was actually ATP.  Genuine firefly luciferin was not purified and structurally characterized until 1959.  In 1962, Shimomura noted the presence of a “green protein” in extracts of the bioluminescent jellyfish.  10 years later this was named “Green-fluorescent protein” (GFP), now the most famous protein in Science and the basis of Shimomura’s Nobel prize in 2008.
In the last two decades we have applied biophysical methods: picosecond dynamic fluorescence spectroscopy, NMR, and structural biology, for uncovering bioluminescence mechanisms.  I will show how this most primitive organism, the jellyfish, early discovered the most advanced physics, quantum correlation, to generate its characteristic green bioluminescence.

Event Date: 
Tuesday, April 24, 2012 - 18:15 - 18:30
Institution: 
University of Sydney
Title: 

Factors affecting insect-associated bacterial communities

Abstract: 

Like all animals, insects harbor bacteria that influence host traits. The factors affecting insect-associated bacterial assemblages have historically been difficult to study due to limited sampling, but recent technological advances in microbial ecology (namely, bar-tagged pyrosequencing) permit the characterization of hundreds of microbial communities. I used this approach to explore insect-associated bacterial communities in three separate studies: 1) Flea-associated bacteria across space, time, and species; 2) Aphid-associated bacteria across space, diet, and host species; 3) Insect-associated bacteria from 87 unique insect species. Results suggest that communities differ among insect species and that communities shift across space and time within insect species.

Event Date: 
Tuesday, April 24, 2012 - 19:15 - 20:00
Institution: 
Nanyang Technological University, Singapore / UNSW
Title: 

The Great Escape: Biofilm formation and dispersal

Abstract: 

Bacteria form biofilms on almost all surfaces, ranging from ship hulls to cooling towers, to indwelling biomedical devices.  Biofilms also play positive roles, for example, floc and granule formation for the biological remediation of contaminated water.  Therefore, there is strong drive to understand the processes of biofilm formation, to either eliminate biofilm formation in some industrial processes and human health, or to encourage their formation, for processes such as remediation.  To develop innovative, environmentally friendly, biofilm control technologies, it is essential to understand the process of biofilm formation and how bacteria control the process of dispersal. 
Bacteria rapidly respond to changes in nutrient conditions, and we have shown that depletion of nutrients, e.g. carbon limitation or nitrogen, can lead to dispersal of bacterial biofilms.  This process is mediated via an intracellular second messenger cascade, using cAMP and c-di-GMP and may also be linked to other physiological signals such as nitric oxide mediated dispersal. 
We have also shown that biofilm development and dispersal is dependent on a prophage carried by Pseudomonas aeruginosa.  The phage plays an important role in multiple aspects of biofilm development and stability and we are beginning to unravel the mechanisms result in phage conversion which ultimately are linked to biofilm development.

Last week’s ABC Science Show had a large chunk on microbial ecology, with interviews with Janet Jansson, Jack Gilbert, and Tiffany Nelson from UNSW at the AAAS meeting.
Here’s a link to the podcast

Sydney may have failed to deliver some sunshine on the last day of a slightly extended summer, but this didn’t dampen the spirits of Sydney’s microbiology community who turned out in numbers for the Inaugural JAMS Anniversary half-day meeting at the Australian Museum. This special meeting celebrated the first birthday of JAMS, an ASM special interest group that aims to bring together research microbiologists, post-docs and PhD students working in non-clinical research from all institutes.

Special thanks must go to the sponsors of the meeting: POCD scientific; Becton, Dickinson and Company; Macquarie University; The University of Sydney; The University of NSW; The University of Technology, Sydney, and; The University of Western Sydney. Another special thank you must also go to Federico Lauro (UNSW) and other members of the JAMS steering committee for organising the anniversary meeting and for their continued commitment to JAMS. The steering committee would also like to thank the Australian Museum who kindly provided the venue for our regular meetings and who hosted this special event.