Morphological, histochemical and biochemical studies on germ cell mitochondria of normal rats

Abstract

Morphological changes in rat germ cell mitochondria are described. In diplotene and secondary spermatocytes and in the spermatids of the Golgi, cap and acrosomal phases, the mitochondria take on a rounded appearance with the inner space containing the matrix flattened against the outer membrane and the intracristal spaces considerably swollen ("condensed" mitochondria). Functional studies on "condensed" mitochondria isolated from the germ cells of normal rats have been performed. The following parameters have been evaluated: ADP/O ratio, respiratory control ratio (RCR) and ADP affinity. The ADP/O values found in the presence of various substrates are in agreement with the theoretical figures. The RCR is remarkably high. Moreover, the ADP affinity of these mitochondria is very high, as demonstrated by the low values of the "apparent Km". These biochemical findings, which demonstrate a high oxidative capacity coupled with a marked phosphorylation, suggest that the "condensed" appearance of germ cell mitochondria is the expression of an active functional state.

SPAF, a new AAA-protein specific to early spermatogenesis and malignant conversion

“…The immunostaining results show that SPAF protein is expressed in the mitochondria of spermatogonia and early spermatocytes in the basal compartment, but not in spermatids and late spermatocytes in the adluminal compartment. Such expression patterns in the seminiferous tubule parallel changes in mitochondrial morphology during spermatogenesis from an`orthodox' form in the basal cells to a`condensed' form in the adluminal cells (De Martino et al, 1979). This suggests an association of SPAF with`orthodox' mitochondrial morphogenesis.…”

“…The signi®cance of this mitochondrial morphological transformation remains to be elucidated. However, condensed mitochondria have been associated with higher oxidative phosphorylation e ciency (De Martino et al, 1979;Hackenbrock et al, 1971). Therefore, it is possible that mitochondrial transformation might be a cellular mechanism to compensate for decreased oxygen supply to cells in the adluminal compartment due to the blood-testis barrier (Waites and Gladwell, 1982).…”

Modifications ultrastructurales des cellules germinales femelles au cours de la prophase méiotique chez le rat : étude particulière des membranes après cryofracture

“…Le complexe synaptinémai a également fait l'objet de nombreuses descriptions ultrastructurales au cours des stades leptotène, zygotène et pachytène (Moens, 1969(Moens, , 1973Stockert et al, 1970 ;Comings et Okada, 1971 ;Esponda et Gimenez-Martin, 1972 ;Schleiermacher et Schmidt, 1973 ;Stack, 1973 ;Chevaillier, 1974 ;Rasmussen, 1976 ;Von Wettstein, 1977 Franchi, 1972 ;Bruslé, 1972 ; (Sotelo, 1959 ;Franchi et Mandl, 1962), ni chez la souris (Tsuda, 1965) Schuchner, 1975 ;chat : Morato, 1965 ;champignons : Stockert et al, 1970 ;plantes : La Cour, 1975 ;souris et cailie : Mirre et Stahl, 1976homme : Très, 1975 ;Stahl et al, 1978Stahl et al, , 1980Hartung et al, 1979 ;Mirre et al, 1980 (Curgy, 1972 ;André, 1962 ;De Martino et al, 1979). Les quelques études des mitochondries réalisées chez la femelle (lapin : Anderson, 1968 ;Anderson et al, 1970) Connell, 1975Connell, , 1976Connell, , 1978rat : Nagano, 1980) …”

Sex selection of sperm in farm animals: status report and developmental prospects

“…Correspondingly, in mice deficient for the calcium extrusion pump membrane calcium ATPase 4 (PMCA4), intracellular calcium overload promotes an increase in the number of condensed sperm mitochondria, which failed to achieve hyperactivated motility (Okunade et al 2004). Oscillatory ultrastructural modifications take place during rat spermatogenesis, transforming mitochondria from orthodox to condensed forms in spermatocytes and spermatids up to the early maturation phase (André 1962, De Martino et al 1979). These condensed mitochondria, which require activin A from Sertoli cells for maintenance (Meinhardt et al 2000), reverted to an 'orthodox-like' appearance during further maturation (De Martino et al 1979).…”

“…Oscillatory ultrastructural modifications take place during rat spermatogenesis, transforming mitochondria from orthodox to condensed forms in spermatocytes and spermatids up to the early maturation phase (André 1962, De Martino et al 1979). These condensed mitochondria, which require activin A from Sertoli cells for maintenance (Meinhardt et al 2000), reverted to an 'orthodox-like' appearance during further maturation (De Martino et al 1979).…”