Monday, July 7, 2008
Science Continues with Bacterial Gossip
Carol Turse, Graduate Student
School of Earth and Environmental Sciences
Washington State University
photo by Emily Taylor
One of the big mysteries in the history of life on our planet is the evolution of organisms from unicellular to multi-cellular life. This transition occurred during the Cambrian Explosion and neither the conditions nor the critical variables are clearly understood. To make matters even more interesting, transitional forms are poorly represented in the fossil record. However, we are extremely lucky to have Pavilion Lake and the microbialites found here as putative transitional forms. These microbialites support a wide variety of bacteria including Cyanobacteria such as Fischerella sp., Pseudoanabaena sp. and Synechoccus sp. These bacterial species have been shown to engage in cell-to-cell signaling (bacterial gossip), more commonly called quorum sensing. This quorum sensing could be extremely important in understanding the evolution of organisms on Earth as well as those that might exist on other planets.
Today I prepared four sets of microbialite samples from two different locations on the lake. The first three sets were from the Three Poles sample site and were collected at 36ft, 42ft and 84ft. I froze small pieces of these samples for later analysis via mass spectrometer and placed the rest in small beakers of a slightly acidic solution. This solution will dissolve the calcium structure allowing me to suspend the remaining microbes in a gelatin-type mix. The different sections of the microbial community can then be isolated from the gel and the DNA extracted for analysis. Another set of samples from Willow point was already suspended in gelatin, so I isolated all the layers in that sample for DNA analysis. In the past I have found several of the genes for quorum sensing in the microbial DNA and I hope this round of samples continues the trend!