The chromosomes of the active previtellogenic oocytes of the dragonfly Cordulia aenea L. extrude into the cytoplasm a substance, which is subsequently found there in the form of granulofibrillar masses. These nuclear extrusions evolve ultrastructurally into two components, nematosomes and dense masses. The nematosomes are later found transitorily adjacent to the mitochondria and undergo transformations that are synchronized with changes in oocyte activity. It is suggested that the nematosomes are storage structures for long-lived informational RNA and that they man be widely distributed in various types of cells containing such RNA.
- © 1975 by Company of Biologists