Will crawling Drosophila larvae lead to brain-injury treatments?

Watching body segments of fly larvae highlighted in green fluorescent protein crawling in a straight line in a very narrow channel is just plain cool. The scientific implications are pretty exciting, too.

Learning the mechanics of Drosophila larval movement is a project of University of Oregon postdoctoral researcher Ellie Heckscher. Her work is supported by a fellowship from the American Heart Association. She works in the Institute of Neuroscience lab run by biologist Chris Doe, a Howard Hughes Medical Institute investigator at the UO.

The researchers also are affiliated with the UO Institute of Molecular Biology.

The larger picture of research in Doe's lab is neurogenesis. As Heckscher puts it: "How do you go from a stem cell to getting the diversity of neurons in the brain?" Her research though is more focused, asking the question: "How do you go from getting the diversity of neurons to making them work together?" She says that this is an entry point into asking the fundamental question about how genes determine behavior.

In the case of newly hatched Drosophila larvae, she has tracked them moving forward and backward in a channel that measures barely 200 microns wide, 200 microns deep and a centimeter long. That's just barely enough room for a single larva to move linearly. The channel was created in the lab of UO biologist Shawn Lockery, with whom Doe and Heckscher have previously collaborated.

What Heckscher saw of the rhythmic whole body behavior with a stereo, or dissecting, optical microscope and of more detailed movement — seven segments and individual muscles — with spinning confocal microscopy provided enough fodder for a research paper.

In the Sept. 5 issue of the Journal of Neuroscience, Heckscher, Lockery and Doe reported that these larvae of insects don't move like already documented soft-bodied organisms, such as leaches and earthworms, which move their segments using a wave that passes through the organism traveling in the opposite direction of the path being taken.

nstead, Drosophila larvae move in two phases, Heckscher explained. First, like a plunger, their tails, heads and guts all jut forward together, next the segments individually catching up as a wave passing through the organism in the same direction as the organism moves.

This new information, Heckscher said, provides basic insight about the movement of an abundant group of animals and has implications at the evolutionary level, which might help determine how and why motion patterns vary from one class of organism to another.

Scientists on a practical level, she says, might tap such information as build robotic organisms with specific duties in mind.

Potential health ramifications surface also surface from this work. At a basic level, Heckscher says, they are documenting developmental stages of normal, or healthy, neuron-to-behavioral activity in an organism that could model the human pathway, albeit in a much more simpler form.

Next up, and already underway, is research in which these neuron-to-muscle pathways are deliberately perturbed to see what happens when defects or brain injuries occur. That line of experimentation may someday provide helpful information related to strokes in humans, and how repairs might be made to compensate for defects or injuries or, better yet, correct the brain's machinery.

"The translational aspect is far away, but it is there," Heckscher says.