ZP3 is believed to mediate the initial binding of sperm and the acrosome
reaction, while ZP2 is involved in adhesion to the sperm's inner acrosomal membrane (Dell et al., 1999).
During the fertilization process, specific protein-degrading enzymes are added to the acrosomal membrane of spermatozoa in the epididymis, and spermatozoa are capacitated by the uterine environment and hormones, thereby completing the acrosome
reaction (Phelps et al., 1990; Barrett et al., 1998).
Labeling by LcH and PNA differed slightly in partially reacted sperm relative to fully opened acrosomes
. In M.
The sperm of Chitonida, including Callochitonidae, are quite different from the typical aquasperm of Lepidopleurida, having an acrosome
that is just a small vesicle at the tip of an elongated nuclear filament (Buckland-Nicks et al., 1988; Buckland-Nicks and Hodgson, 2000; Buckland-Nicks, 2006), and an acentric basal body comprising the two fused centrioles (Hodgson et al., 1988; Buckland-Nicks, 2008).
Proper acrosomal integrity is essential for the acrosome
reaction a prerequisite for successful fertilization and subsequent fertility.
Likewise, there was a significant decrease in intact acrosomes
in the 118-mJ/[cm.sup.2] irradiated sperm relative to the control based on a t-test (t = 4.7, df = 4, P = 0.0093) (Fig.
The ultrastructure of late stages of oogenesis has been reported (Morisawa, 1999b), but the fine structure of spermiogenesis in Myxine glutinosa and Eptatretus stouti (Alvestad-Graevner and Adam, 1977; Jespersen, 1975) was studied before papers about the acrosome
reaction (Morisawa, 1999a; Morisawa and Cherr, 2002) were published.
Freezing process accelerated the ROS production and reduced anti -oxidative activity which resulted in decreased motility, plasma membrane integrity and intact acrosomes
of buffalo bull spermatozoa (El-Sissy et al., 2007).
Although it was not possible to expose only sperm to CB because washing disrupted the fragile acrosomes
, polymerization of sperm MFs is not believed to be the critical component in sperm entry.
The mechanism of fertilization must be quite different in these lepidopleurids compared to Chitonina such as Stenoplax conspicua (Buckland-Nicks, 1995), or Acanthochitonina such as Tonicella lineata (Buckland-Nicks et al., 1988b), because of basic differences in sperm acrosomes
and egg hull structure.
In addition, capacitation, acrosome
reaction and the oocyte penetration require a biochemically active sperm plasma membrane (Jeyendran et al., 1984).
This method can better determine the size and position of spermatid acrosomes
. Using this latter approach, characterization of the seminiferous epithelium stages is determined based on the presence, angle, and size of the acrosome
, shape and location of spermatid nuclei, presence of meiotic division, and overall components of the testicular seminiferous epithelium.
Cryopreservation causes permanent functional damage to sperm viability that can be explained partially by the reduction in the percentage of normal intact acrosomes
and in total acrosin activity.
Two hundred heads of spermatozoa per slide were counted for acrosome
abnormalities such as swollen, ruffled or absent acrosomes
Under the oil immersion lens, we found in partial globozoospermia not only a large number of acrosomeless sperm, but also lots of sperm with small acrosomes
. The head of acrosomeless sperm looked like a ball (red arrow, [Figure 1]), and the head of small-acrosomal sperm was thin and pointy, which made it look like a sunflower seed (yellow arrow, [Figure 1]).