NSF Minority Postdoctoral Research Fellowship for FY2008

Welander Paula V, Arlington MA

Investigators

Abstract

This action funds an NSF Minority Postdoctoral Fellowship for FY 2008. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Paula V. Welander is "Elucidating the biosynthesis and physiological function of hopanoid lipids in phototrophic bacteria" and is under the sponsorship of Professor Dianne K. Newman at the Massachusetts Institute of Technology. The atmosphere of the ancient Earth was composed primarily of carbon dioxide, some nitrogen, and essentially no oxygen. It is thought that, through oxygenic photosynthesis, cyanobacteria (also known as blue-green algae)were responsible for the oxygenation of the Earth's atmosphere. Modern cyanobacteria are significant producers of 2-methylhopanoids, which are lipids similar in structure to sterols such as cholesterol. Because cyanobacteria are the only microbes capable of oxygenic photosynthesis, 2-methylhopanoid fossils discovered in ancient rocks and sediments have been used as "biomarkers" for both cyanobacteria and oxygenic photosynthesis itself. However, significant 2-methylhopanoid production has been recently discovered in another bacterium, Rhodopseudomonas palustris, which also uses photosynthesis for growth, but does not produce oxygen in the process. The main objective of the research plan is to understand why bacteria produce 2-methylhopanoids and determine if these molecules are appropriate markers for oxygenic photosynthesis. This research is is identifying the genes required to produce 2-methylhopanoids in R. palustris and then create gene deletion mutants that are no longer able to produce 2-methylhopanoids. These mutants are being used to demonstrate how the lack of 2-methylhopanoids affects the growth, physiology and structure of this organism. This research provides an excellent opportunity for interdisciplinary training in molecular geobiology with extensive training in bacterial metabolism. The broader impacts include increasing the participation of an underrepresented group at the postdoctoral level. The Fellow is serving as a role model and mentoring students through outreach programs in biology.