Mitochondrial distribution, quantification, and architecture in functionally plastic sensory neurons.
By: Julio Espinosa Robles
Department: Cellular & Molecular Biology
Faculty Advisor: Dr. Ivan Anastassov
The mixed rod-cone retinae system, the kind found in humans, use rods to see in low light conditions while cones are used brighter settings. Rods and cones are the sensory neurons that detect light in all vertebrate retinas. Interestingly, the retina of a fish called a skate has only rods and no cones. It would follow that their vision would be limited to low light levels, however, skates are able to function at bright (i.e., photopic) light levels-a domain that is usually handled by cones. A better understanding of the rod physiology may shed light on the reason for this unique characteristic of the skate retina and this project focuses on the mitochondrial aspect of these cells. Reconstruct is a program that allows images obtained from serial block-face 3D electron microscopy to be traced and converted into a 3D object. These objects can be converted into models that allow for various measurements to be gathered, for example: how different organelles interact physically with one another, or the surface area and volume of an organelle. This approach was used to quantify the number of mitochondria present in the skate rod cell, as well as their dimensions, and to gather qualitative interactions between mitochondria. These data are important as cones consume more ATP than rods so there may be unique adaptations or differences present in the mitochondria of the skate rod cells that are not present in the mixed rod-cone retinae system, which could contribute to our understanding of how the pure-rod visual system of skate functions across light intensities.