JAMS Report September 2012


In September, JAMS was back into top gear, with a bigger audience, and a room with a view. Kent Lim from Macquarie University led off with a talk on his PhD work on the biocontrol agent Pseudomonas strain Pf5. As is often the case in science, things didn’t work out as expected, and Kent found that knocking out suspected pyochelin transporters led to an increase rather than a decrease in efflux of this siderophore and its metabolic precursors. Kent valiantly soldiered on, applying qRT-PCR and Biolog phenotype microarrays to untangle the problem, but unfortunately, this released even more worms from the seemingly-bottomless can provided by strain Pf5. It seems that these transporters may in fact also be regulatory proteins, explaining the unexpected pleiotropic effects of the knockouts.
The second speaker was postdoc Ani Penesyan, also from the Paulsen lab at Maquarie Uni, who was attempting to discover the ‘natural’ substrates for the multidrug efflux pumps of Acinetobacter baumannii. Ani’s approach was to think about where Acinetobacter may have evolved before coming into contact with people and hospitals – this led her to soil and to biofilms; places where cells may be challenged by toxic plant metabolites, or the need to export signalling molecules. Using qRT-PCR, Ani showed that soil extract, plant metabolites, and biofilm conditions all up-regulated the ‘effluxome’ of A.baumanni. This work was especially interesting since the natural niche of A.baumanni is still controversial – could A.baumannii be a friendly rhizosphere bug that has recently turned to the dark side….?
The keynote speaker for the evening was Sabrina Beckmann, a postdoc working in the Manefield lab at UNSW, who talked about microbial methane formation from coal. The audience was greatly entertained by Sabrina’s slide show of sampling in deep, dark, abandoned German coal mines, where occupational hazards included the low oxygen content, the constant threat of mine collapse, the heavy fungal spore load in the air, and the hideous sight of your supervisor’s bottom filling the tunnel ahead. Sabrina provided evidence that methane in these environments is at least partially biogenic, due to the activity of acetoclastic methanogens. Some very unexpected microbes (eg. the “marine” crenarchaeote Nitrosopumilus) seem to play an important, though as-yet unknown, role in this process.
As the peak hour traffic died away, and quiet descended on the city, the remaining beers were swilled, the pizza boxes were stacked, and we left the Museum, eagerly awaiting next month’s instalment.