Figure 7.

Evaluation of exocytotic activity of cells transformed with ND7 sequences. The dark-field image shows cells treated with picric acid. Clonal descendants of cells injected with pND7−, which do not secrete any trichocysts (exo−), are shown above an nd7 cell whose exocytotic capacity has been restored (exo+) by transformation with a functional ND7 gene (pND7+). The latter, which is indistinguishable from uninjected wild-type cells, is surrounded by a dense halo of trichocysts. Magnification, ×200.