Mechanosensational
Kelly Grant (UCDHSC), Dave W. Raible (UCDHSC)

Immunofluorescent confocal microscopy, Adobe Photoshop
The photomicrograph shows the lateral line of a 4 day old-zebrafish. The lateral line is a sense organ in aquatic vertebrates that detects vibrations in the water. The cells that make up the lateral line have the same form and function as the cells in our inner ear that allow us to hear. Both the inner ear and lateral line are made up of specialized "hair cells," so named because they are topped with a tuft of cilia. The cilia on these cells bend in response to vibrations and send an electrical signal to the brain that we have heard a sound or that a big fish is approaching. So these hair cell serve an important function, but the mammalian inner ear is found inside the hardest bone of the body, making these cells difficult to study. Conveniently, the lateral line is on the surface of the fish's body making experiments much easier.

The living fish was soaked in the dye, FM1-43, which was taken up by the active mechanosensory hair cells (pink). The fish was then immunostained with an antibody that marks the nerve (green), as well as the long cilia of the hair cells (pseudo-colored blue). The image was duplicated and reflected in Adobe Photoshop. This particular fish is a mutant that lacks the glia that normally insulate the nerve. The absence of glia causes the nerve to become unanchored and curve inappropriately. Additionally, the nerve frays because the axons that make up the nerve fail to stick together. We have used these mutants to study the interaction between glia and lateral line stem cells; without glia, the stem cells become too active and make too many hair cell clusters.

Traveling