Monday, August 18, 2008

ISME 12 Cairns - Highlights of Sunday and Monday

The first two days of ISME went quite well. First of all, I have to give the organizers high marks for actually providing a conference bag worth having (BTW, it would be interesting to figure out someday where and when the custom of "conference bags" started -- why does every conference assume that attendees need a conference-specific bag?) Rather than the nearly useless tote bags which one often gets, the ISME 12 bag is a nice high quality backpack that will be worth keeping after the conference. Conference bags may be a minor issue, but a quality bag is a nice touch.

Bo Barker Joergenson gave a nice keynote on Sunday night on the subject of the "deep biosphere" by which he means microbes living deep in the sediment at the bottom of the ocean. Ships have returned drilled cores even from a couple of kilometers down that contain microbial cells. For many years there was debate over whether these cells were actually alive or just the "corpses" of cells that drifted down and never decayed, but now there is general agreement that there are living cells. What there isn't agreement at this point is what type of cells there are. Some groups, using Q-PCR have concluded that the primary players are bacteria; others using FISH-IPL say archaea are. As a bioinformatician, I find this conflict of experimental methods disturbing. Still, the "deep biosphere" is a fascinating topic to me.

After the keynote we had appropriately Australian entertainment; a group of local indigenous Murri demonstrated some traditional songs and dances and the use of firesticks.

On Monday the main series of talks began. Curtis Suttle talked about inferring the host species of marine viruses through phylogeny. He began with some fascinating statistics; there are 10^30 viruses in the ocean, and if they were laid end to end, they would stretch for 10^7 light years! And they contain more carbon than 75 million blue whales. So what exactly are these viruses infecting? Suttle has developed an interesting method where he first calculates phylogenies of viruses with known hosts, calculates the average genetic distance between viruses that infect the same host, and uses this distance to cluster sequences of viruses that infect unknown hosts. He then looks for correlation between occurrences of members of these clusters with morphologically different hosts in micrographs to assign presumed hosts. Obviously, morphology is a crude measure of species in any set of organisms (and particularly so for microbes), but it is a useful start.

Forest Rohwer, probably the best known researcher of marine viruses, gave a talk about many different projects his lab is pursuing. What I found most interesting was his idea of measuring the energy usage of phages by measuring temperature in calorimeters containing bacterial cultures with and without phages.

C.D. Long presented a good example of what I find most interesting in science -- the application of a technique developed for one problem to a different one. In this case, she utilized the traditional "checkboard" method (developed by ecologists studying island biogeography) to analyze the co-occurrence of different microbial species living on human teeth. I'll have to read up on the method to see if maybe I could do something similar.

And Mitch Sogin presented on his idea of the "rare biosphere" -- the idea that most microbial species are very low abundance organisms. I've heard Mitch talk about this idea before, but this talk was more technical and included more details --- not only of his experimental methods but also of his VAMPS analysis system. I've spent a lot of time basically writing my own version of many of the methods there because I didn't know the system existed.

P.S. Qantas found Lisa's bags.

No comments: