Maintenance of function in single epithelial cells spatially isolated from similar cells

We have found in an insect tissue, the Malpighian tubules of Rhodnius, instances of single epithelial cells which, as the result of a possible error in development, lie within the epithelium some distance from the main population of similar cells. This spatial separation makes it possible to measure the transport abilities of these cells. Their transport abilities were found to be the same as the cells in the main population. This finding shows that the maintenance of function in individual cells of epithelial tissues may not depend on direct contact with other similar cells.