The membranes of Limulus (horseshoe crab) sperm were examined before and during the acrosomal reaction by using the technique of freeze-fracturing and thin sectioning. We focused on three areas. First, we examined stages in the fusion of the acrosomal vacuole with the cell surface. Fusion takes place in a particle-free zone which is surrounded by a circlet of particles on the P face of the plas...

Sea urchin sperm motility is modulated by sperm-activating peptides. One such peptide, speract, induces changes in intracellular free calcium concentration ([Ca2+]i). High resolution imaging of single sperm reveals that speract-induced changes in [Ca2+]i have a complex spatiotemporal structure. [Ca2+]i increases arise in the tail as periodic oscillations; [Ca2+]i increases in the sperm head lag...

Male ICR mice were orally administered samarium nitrate [Sm(NO3)3] to investigate its effects on sperm concentration and sperm quality. After acute exposure to ≥2880.00 mg/kg Sm(NO3)3 via intragastric gavage, sperm motility and acrosome integrity were decreased, and the sperm malformation percentage was increased (P < 0.05). After subchronic exposure to ≥500.00 mg/L Sm(NO3)3 administered via dr...

Background: Mammalian spermatozoa are characterized by a high proportion of polyunsaturated fatty acids (PUFA) and the membrane structure of spermatozoa plays a crucial role in fertilization. Moreover, dietary fatty acid (FA) influence sperm FA profiles in several species. This study focused on responses to dietary omega-3 fatty acids and comprehensive fatty acid profiles analysis in men as wel...

Background: To clarify the mechanism of sperm penetration through the zona pellucida, the flagellar force generated by a hyperactivated spermatozoon was evaluated using the resistive force theory applied to the hyperactivated flagellar waves that were obtained from the mammalian spermatozoa. Materials and Methods: The hydrodynamic calculation of the flagellar force of the activated (non-hyperac...

The mouse oocyte can be activated by injection of a single, intact mouse spermatozoon or its isolated head. Isolated tails are unable to activate the oocyte. Active sperm-borne oocyte-activating factor(s) (SOAF) appears during transformation of the round spermatid into the spermatozoon. The action of SOAF is not highly species-specific: mouse oocytes are activated by injection of spermatozoa fr...

To clarify the physiological changes of sperm morphology in active Thoroughbred stallions during the breeding season, we examined the dismount semen collected from the penile urethra immediately after service. The spermatozoa were analyzed for relationships between the morphology and the stallion's age or the number of services. Seasonal variation was apparent in the rate of the sperm tail abno...

BACKGROUND One of the semen quality parameters use to determine fertility is the percentage of sperm that express normal morphology. Sperm head morphometry is also correlated with fertility. The objectives of this study were 1) to investigate the sperm morphology and normal sperm head morphometry of Thai native crossbred stallions, and 2) to compare our results with the characteristics of prove...

Commercial ostrich farming is constrained by the absence of a formal animal recording and evaluation scheme as well as by current farming practices. Artificial insemination may have an important role in overcoming these limitations, but requires a thorough knowledge of sperm morphology. Although the morphological characteristics of normal ostrich sperm have been documented, little information i...

Sperm morphology is unique among the known cells and 3 major parts can be immediately distinguished: head, midpiece and tail. Normal sperm exhibit an oval-shaped head with a regular outline and a cap (acrosome) covering more than one-third of the head surface. The midpiece is slender, less than one third of the width of the head, straight and regular in outline. The tail is slender, uncoiled an...