The discovery of the pathways in the protozoan resulted from an observation made by Gavin about 10 years ago while simply watching cells through a microscope. "I am a patient and constant observer of living things," he says. "And I watch them all the time with no agenda in mind. Some people are window gazers. They stand in front of the window and just look. I do the same with cells."
During one of Gavin's agenda-less cell-watching sessions, he noticed phagosomes clustered around a cell's nucleus. "It made me wonder why the phagosomes were positioned in that way," Gavin said. Thereafter, Gavin periodically looked for this intriguing behavior again, and occasionally glimpsed it again.
But Gavin remained unable to systematically search for phagosome clusters around nuclei until he received NSF funding in 2006 to purchase a confocal microscope, which provides three dimensional views of the cell. Just like a person would eventually find a worm hidden in an apple by repeatedly slicing through the apple, Gavin found the intruiging phagosome behavior he sought by using the confocal microscope to repeatedly obtain views that sliced clear through the cell.
Specifically, the team tracked phagosomes carry extracellular material into the cell nuceli by introducing fluorescent latex beads into the area outside of the cell. They then observed the cells phagocytose (eat) the beads, which gradually moved to the nucleus. The arrival of the phagosomes and their loads at the nucleus was marked by the illumination of the nucleus by the beads. Similarly, the researchers also labeled the cellular membrane with a fluorescent dye, and then observed the pinched off, internalized membrane move to the nucleus.
"Biologists may now study the
|Contact: Lily Whiteman|
National Science Foundation