Visualization of accessory nuclei from oocytes of the sawfly Athalia rosae (Hymenoptera: Tenthredinidae) by a spreading technique.

Oocytes of hymenopterans are equipped with specific organelles termed accessory nuclei (AN). These organelles are surrounded by a double envelope and contain RNA-positive inclusions. We have employed the spreading technique to analyse AN isolated from the ooplasm of the sawfly Athalia rosae. In electron microscopic spreading preparations AN appear as membranous, extensively folded structures. In their vicinity, numerous nuclear pore complexes have been found. This observation confirms the presence of pores in the envelopes of accessory nuclei.