JAMS April 2012 Report

JAMS Meeting Report – April 2012
by Thomas Jeffries
 
There was a good turnout on ANZAC day eve for three interesting talks, pizza and free local beer.
 
Kicking off the evening was John Lee, from the University of Georgia, with his ambitiously titled talk “Bioluminescence: The First 3000 Years”.  After a historical introduction to the long running observation of bioluminescence, via the discovery in 1672 that oxygen was necessary for bacterial luminescence, John told us how it was determined that bioluminescence is an enzyme mediated chemical reaction involving “luciferase” and "luciferine". In the modern age of biochemistry it was determined that ATP is the substrate in this reaction.  Following the elucidation of the structure of firefly luciferase in 1959, modern techniques (i.e. picosecond dynamic fluorescence spectroscopy and NMR) have allowed researchers to uncover the enzymes and processes involved in bioluminescence.  One of the most important of these enzymes Green-fluorescent protein (GFP) was discovered in jellyfish by Shimomura (who evidently has a lab at his house!) and led to his Nobel prize in 2008.  Due to GFP’s widespread use in research, it is regarded as one of the most important proteins in science.
 

Next up was Ryan Jones, from the University of Sydney, with a discussion of microbial biogeography as mediated by insects.  Using tag-encoded pyrosequencing, he demonstrated that different insect species harbour distinct communities and that within species these community signatures vary both temporally and spatially.  This work focused on aphids and fleas as well as a meta-analysis of 87 insect species. In addition to these insect systems being great models for microbial ecology, one application of this work relates to understanding the spread of the Plague.  Using Prairie Dogs as a model, and some lab work that the average microbial ecologist tends to avoid,  Ryan showed us that the plague is still prevalent and that flea associated bacterial communities shift in response to infection by Yersinia pestis (the causative agent of plague).
 
Rounding off the somewhat American themed evening was Scott Rice, visiting from Nanyang Technological University in Singapore and formerly of UNSW.  His talk entitled “The Great Escape: Biofilm formation and dispersal” began with an introduction to bacterial biofilms, which are of huge relevance to ecology, industry and medicine.  Thus, understanding the molecular mechanisms of biofilm formation, to either eliminate or to encourage their establishment, is of great importance.  One factor which controls biofilm stability is nutrient concentration, with biofilms dispersing in nutrient limited conditions.  This is process is mediated by intracellular biochemical cascades.  Quorum sensing is also a vital process in the establishment of biofilms.  Using the clinically relevant Pseudomonas aeruginosa as a model, Scott showed how biofilm development and dispersal is also dependent on a prophage.  This phage plays an important role in development and stability and using genetic manipulations of this system the mechanisms which result in phage conversion and ultimately biofilm development have been elucidated.