The Roles of Mitochondrial Behavior and Morphology in Animal Performance

Auburn University, Auburn AL

Investigators

Abstract

Mitochondria are components of cells that produce energy in the form of the chemical ATP and perform numerous other core cellular processes. This project investigates how the shape and connectedness of mitochondria affect energy production at the cellular and whole-organism levels. ATP fuels nearly all physiological processes that occur in the body, shaping the energy utilization strategy and pace of life for each species. Mitochondria alter their shape (morphology) and move within the cell to interact with one another, a process referred to as mitochondrial behavior which appears to affect ATP production. The following hypotheses are being tested: 1) Changes in mitochondrial morphology and behavior increase ATP production, and 2) Mitochondrial behavior and morphology play key roles in the performance of animals, as indicated by how they respond to low food availability, reproduction, and aging. These ideas will be tested in two distantly related species, a copepod (a species of zooplankton found in tide pools) and the house mouse. In addition, research on mitochondria will be used as a platform for science education and the improvement of science literacy in Alabama. In collaboration with local biology teachers, an integrative and inspiring laboratory for high school students will be created. Teachers in East Alabama will be trained in the application of this laboratory. Once completed, the laboratory will be submitted to the Alabama State Board of Education for review. If approved, it will be available for use in every high school biology classroom in Alabama. The project also involves training and mentoring of graduate students, and a collaboration with a rural nature center to provide outdoors, hands-on experience with invertebrate biodiversity to more than 600 local participants. Organisms convert chemical energy into ATP to support essential processes including growth, self-maintenance, and reproduction. Mitochondria synthesize the majority of ATP that fuels energetically demanding processes in the body through oxidative phosphorylation. Mitochondria alter their shape, i.e., mitochondrial morphology, and move within the cell and interact with one another, a process termed mitochondrial behavior. Modifications to mitochondrial morphology and behavior affect the process of ATP synthesis. Biomedical research has shown that abnormal mitochondrial behavior and morphology can lead to disease. However, while mitochondrial behavior and morphology are altered under extreme conditions (e.g., parasitism, starvation), limited data exist that investigate how these key changes impact typical energetically demanding animal behaviors and life history strategies. The following overarching hypotheses are being tested in two distantly related species, the aquatic copepod Tigriopus californicus and the terrestrial house mouse Mus musculus: 1) Increased expression of inner mitochondrial membrane and inter-mitochondrial junctions improve the performance of the electron transport system, and 2) Mitochondrial behavior and morphology play key roles in the performance of animals, as indicated by how they respond to low food availability, reproduction, and aging. This project utilizes an integrative approach by linking cellular processes to whole-animal performance traits and by incorporating a wide array of research tools, including transmission electron microscopy, whole-organism and mitochondrial respiration assays, cell perforation, mitochondrial protein analysis, and direct manipulations of mitochondrial function and structure, including the alteration of electrochemical gradients within the electron transport system. This project is jointly funded by the BIO-IOS-Physiological Mechanisms and Biomechanics Program and the Established Program to Stimulate Competitive Research (EPSCoR). 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.