The Ultrastructure of the Synaptonemal Complexes in Galleria mellonella (Lepidoptera) Spermatocytes

Fine structure of synaptonemal complexes (SCs) was investigated in primary spermatocytes of Galleria mellonella testes. In longitudinal sections, the SCs were discriminated as linear or curved rods in the prophase nuclei of the first meiotic division. These rods were attached to the inner surface of the nuclear envelope by their one end. Two electron dense axial or lateral elements were clearly distinguished in fine structure of the SCs. A central element was formed by parallel bands with a lesser electron density than the lateral elements. The diameters of the central and the lateral elements were 37 nm and 48.7 nm, respectively. The central element is embedded within the electron lucent central region. Fine transverse filaments crossing the central region between the lateral and central elements were seen. The width of this area was measured 40.4 nm. Taken together, total diameter of the SCs in the testes of G.mellonella reaches to 218 nm.