Princeton Molecular Biology Outreach Program

April 23, 2009

Professor Zemer Gitai "Can understanding how bacterial cells are built help to combat infectious disease?" On a gorgeous spring evening, with magnolias in full bloom across campus, over 300 students and teachers streamed into McCosh auditorium to hear Professor Zemer Gitai share his research on bacterial cellular architecture. Professor Gitai immediately caught their attention by telling the audience that we are running out of antibiotics and losing the arms race against pathogens, such as MRSA. The incidence of MRSA has been on the rise in the last 20 years while the development of new antibiotics has declined in that same period. Most antibiotics target a bacterial cellular product. Showing a slide of variations in bacterial morphology, Professor Gitai explained that the variety of shapes as seen in spirals, rods, spheres and crescents, depends on the cytoskeleton. Professor Gitai made the observation that bacteria are excellent model organisms for research because they grow so fast. He calculated that one bacterial cell, doubling under perfect conditions every 20 minutes, would end up as a mass weighing more than the planet Jupiter in just 48 hours. This fast growth and amazing cell numbers allows scientists to study extremely rare mutations. His own research is focused on the organism Caulobacter crrescentus. This microbe does not divide in half, but rather off center, producing a smaller swarmer cell and a larger stalked cell. In order to study where proteins localize, Professor Gitai’s lab used GFP (green fluorescent protein) to make a fusion protein. By utilizing different colored fluorescent proteins, scientists can track multiple proteins and see where they localize over time. Approximately 20% of proteins made by bacteria are necessary for survival. Professor Gitai is searching for a way of disrupting the function of these essential proteins. Screening for promising new antibiotic compounds that target specific cytoskeletal proteins has led to one promising candidate, dubbed A22. A22 is a small molecule inhibitor of MreB, which is an actin homolog. MreB, an essential cytoskeletal protein, starts as a monomer then polymerizes into rods and gives shape to the cell. Professor Gitai fielded great questions following his talk. Among them were questions on the GFP fusion protein and whether the GFP segment would interfere in the normal function of the protein and whether if patients were treated with A22 would some bacteria eventually develop resistance to A22.

Dr. Manuel Llinás Fall '08

Dr. Dan Notterman Spring '08

Dr. Coleen Murphy Spring '07

Past TIGER Talks Speakers