Acquisition of an environmental microscope/microfluidic system to enable new capabilities in the microbial sciences at Caltech
Abstract
Regardless of their context, the rules underpinning biofilm structure and function are poorly understood. Yet in order to design synthetic biofilms to perform specific tasks, we need to understand the rules governing natural biofilms. Our current ARO-supported research project (W911NF-17-1-0024) attempts to understand an aspect of what makes some biofilms metabolically robust: how do electron shuttles mediate extracellular electron transfer (EET) within biofilms? How is the metabolic activity of an electron shuttle-producing organism affected by the presence of other organisms that respond to that electron shuttle in different ways? These questions address a core challenge biofilm cells faceÑmaintaining metabolic activity in the face of oxidant limitation. We are using a simple biofilm system comprising Pseudomonas aeruginosa (a model extracellular electron shuttle (i.e. phenazine) producer) and a small number of other organisms that do not produce phenazines but respond to them in different ways (positively, neutrally, or negatively). We hope to better understand how phenazines mediate EET through the P. aeruginosa biofilm matrix, and how the presence of phenazine nonproducing organisms in the biofilm impacts the spatiometabolic organization of P. aeruginosa under different environment conditions, particularly gradients of oxygen. Because this experimental system is highly tractable, our hope is that a Òbottom upÓ approach will allow us to identify a set of principles that can be abstracted to more complex microbial communities that are oxidant-limited. Lessons learned from these studies will shed light on how microbial communities that rely on EET self-assemble as a function of the presence of an electron shuttle. A key limitation we face in achieving our goals is the lack of an appropriate environmental microscope/microfluidic system. Recently, innovations in microfluidics and wide-field image deconvolution have made it possible to observe single cells over the course of biofilm development with unprecedented spatial resolution and quantitative sophistication. Such systems are now the gold standard for the field, yet Caltech lacks one (please see letter of support from Dr. Andres Collazo, head of the Caltech Biological Imaging Center). Not only do we seek to acquire a wide-field fluorescence microscope and couple it to a robust microfluidic system, but we propose to employ this system within an environmental chamber where we can regulate oxygen and other environmental variables. Initially, the instrumentation will be located in the Newman lab, which is certified to study biosafety level two (BL-2) pathogens, but in a few years, we hope to move this system into a shared resource center at CaltechÕs Beckman Institute. Together, the combination of attributes this system will possess (quantitative single-cell tracking capability under different environmental conditions for a range of species, including BL-2 pathogens) will provide a unique campus resource and broadly benefit research and research related education at Caltech.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810236
Entities
People
- Dianne Newman
Organizations
- Army Contracting Command
- California Institute of Technology
- United States Army