CAREER: Experimental Investigation of Morphogenesis and Locomotion of Multicellular Magnetotactic Bacteria

Clark University, Worcester MA

Investigators

Abstract

The study of Multicellular Magnetotactic Bacteria aggregates will elucidate the physical mechanisms underlying the evolution of multicellular life. These aggregates are unique in their ability to coordinate the growth and collective motion of their constituent cells. Understanding this ability will contribute to the design of biomimetic micro-systems. The proposed research is the first integrated experimental and theoretical study of the growth, form, and hydrodynamics of Multicellular Magnetotactic Bacteria. The PI will design a new course on "Modeling Biological Complexity." Unlike traditional biophysics courses, the course will focus on the tools and techniques necessary to study and model uncultured bacteria, microbial communities, ecosystems, and nutrient cycles. This course will help prepare students to address the challenges of climate change. Students of all levels will be recruited to join the PI's research group. The PI will participate in science expositions. The PI will design new demonstrations that will allow members of the public to observe living Multicellular Magnetotactic Bacteria under a microscope and guide them using magnets. The project aims to understand the physical mechanisms that facilitate the evolution of multicellular life. The research focuses on Multicellular Magnetotactic Bacteria, which represent an intermediate between unicellular and multicellular life. These bacteria live exclusively in spherical aggregates composed of 10–60 cells, which quickly die when separated from the aggregate. Cells in an aggregate precipitate magnetic crystals, which align in a common direction. The cells work together to push the aggregate along magnetic field lines. As cells in an aggregate reproduce, the aggregate grows, elongates, and divides into two similarly sized aggregates. The physical mechanisms that underlie this remarkable cooperative behavior are poorly understood. It is not known how cells coordinate their growth, align their magnetic moments, and coordinate their motility. The project will investigate, through a combination of experiment and theory, how the interactions between cells as they grow and rotate their flagella allow the cells to behave like a single multicellular organism. These types of interactions may have facilitated the evolution of complex life by allowing cells in a proto-multicellular group to cooperate before the evolution of shared chemical signaling pathways. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.