Biophysical Society Bulletin | December 2021

Biophysicist in Profile

Julie Biteen Area of Research: Single-molecule fluorescence imaging

Institution University of Michigan

At-a-Glance

Julie Biteen has always had a quantitative mind, but thought she would pursue a career in civil engineering until she fell in love with basic research during her undergraduate years thanks to the influence of great teachers. Now, years later, she is a professor of chemistry and of biophysics at the University of Michigan.

Julie Biteen

Julie Biteen grew up in Montreal, Canada, where her father worked in human resources and her mother was a librarian. “My father worked in compensation and benefits, so he was the quantitative person in my family,” she shares. “My mother was a librarian, so she taught me that it’s more important to understand the underlying questions than to memorize any specific details as you can always look those up.” From an early age, Biteen enjoyed math and was intrigued by the idea of using quantitative skills to solve real-world prob- lems. “Growing up, I wanted to work at the interface of civil engineering and urban planning. However, I really fell in love with basic science in college thanks to some great chemistry teachers. I cannot imagine doing anything other than chemis- try and optics—if I wasn’t a biophysical chemist, I would likely be doing work on nanochemistry,” she says. “I’ve also always been fascinated by optics questions like ‘why is the sky blue?’ and ‘why do fireflies light up in the dark?’ so I did optics re- search as an undergraduate and PhD student in chemistry.” She attended Princeton University for her undergraduate studies, earning her degree in chemistry, followed by a mas- ter’s of science in applied physics from the California Institute of Technology, where she then earned her PhD in chemistry. “I first started thinking about biophysics when I was looking for a postdoctoral research position. The way I had previ- ously learned biology felt very observational, but biophysics provided the opportunity to apply quantitative methods and physical principles to biological problems!” she remembers. “In particular, toward my interests, I was thrilled to have the chance to apply my expertise in fluorescence and quantitative image analysis to understand how bacteria cells are orga- nized.” Biteen undertook a postdoctoral position in the lab of W. E. Moerner in the Chemistry Department of Stanford University. “I made the transition from solid-state physics in my PhD to biophysics in my postdoc when I was given the opportunity to work on applied bacteriology projects with W. E. Moerner,” she

explains. “From my time with W. E. and the rest of the Mo- erner lab, I became an expert in single-molecule fluorescence microscopy and bacterial cell imaging. Furthermore, I was fortunate to have great collaborators during my postdoc: we worked together with Lucy Shapiro in Developmental Biology at the Stanford University School of Medicine. From meetings and conversations with Lucy and the rest of the Shapiro lab, I began to develop real insight into bacterial cell biology.” During her postdoc, she developed the first super-resolution (photoactivated localization microscopy) images of protein assemblies in living bacterial cells: “We imaged the structural protein MreB in living Caulobacter crescentus and found that this protein organizes in helices or rings at different times in the cell cycle.” Biteen is a professor of chemistry and of biophysics at the University of Michigan. Her lab works on directly observing the positioning, dynamics, and interactions of proteins in microbial cells and relating these biophysical observations to biochemical processes in the cell. “We attack this challenge by developing single-molecule microscopy methods; by designing data analysis algorithms for tracking, background subtraction, and classification; and by integrating genetic mu- tations into our studies to relate motion and function. My lab has recently developed a new algorithm, NOBIAS, that uses Bayesian analysis to separate single-molecule trajectories into different states of motion and then uses machine learn- ing to assess anomalous diffusion behavior for each state. We are applying algorithms like this one to understand different fundamental subcellular processes in living microbes—cur- rent projects range from understanding carbohydrate utili- zation by gut microbes in collaboration with Nicole Koropatkin at the University of Michigan Medical School; to measuring epigenetic regulation via histone modifications in fission yeast in collaboration with Kaushik Ragunathan , also at the Univer- sity of Michigan Medical School; to quantifying the chromo- some stress response in Escherichia coli in collaboration with Anne Meyer at University of Rochester,” she shares. “We are also developing methods to enhance fluorescence with metal

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