Ultrastructure of spermatozoa from Japanese quail

A monoclonal antibody (mAb) to epitopes on mitochondria from turkey spermat ozoa cross-reacted with Japanese quail spermatozoal mitochondria. However, the pattern of binding was different from that observed for turkey sperm Th e ultrastructure of quail spermatozoa was examined to determine the reason for this difference in antibody binding pattern. Light microscopy, as well as scanning (SEM) and transmission (TEM) electron microscopy, were used to study the morphology of spermatozoa from Japanese quail. Japanese quail had a sauropsid type of sperm cell, which is typical of nonpasserine birds. Th e spermatozoa were vermiform in shape, with a maximum width of 0.6 mu m and an overall length between 230 and 250 mu m. An acrosome (3.7 to 4.5 mu m), nucleus (20.8 to 23.8 mu m), midpiece (160 to 170 mu m), and tail (40 to 6 0 mu m) were observed. The TEM showed an acrosomal cap surrounding a perfor atorium that inserted into the nucleus at the posterior end. Only a distal centriole was observed, which gave rise to a central axoneme with a 9+2 mic rotubular structure. The axoneme was encased by a spiraled mitochondrial sh eath in the midpiece region (64 to 74% of the overall length of the sperm), and mitochondria numbers were estimated to be greater than 1,400 per sperm . In contrast, turkey sperm contain short midpieces with only 20 to 30 mito chondria per sperm. Differences in binding patterns of the mAb to turkey mi tochondria between quail and turkey sperm were due to the presence of mitoc hondria on the exceptionally long midpieces of quail sperm.