Reaction acrosome

Tilney, L.G. Inoue, S. (1982). Acrosomal reaction or Thyone sperm. 11. The kinetics and possible mechanism of acrosomal process elongation. J. Cell Biol. 93, 820-827. 

Tumer KO, Syvanen M, Meizel S. 1997. The human acrosome reaction is highly sensitive to inhibition by cyclodiene insecticides. J Androl 18(6) 571-575. 

In addition, anandamide was found to parallel classical cannabinoid pharmacology in a series of nonbehavioral experimental systems. In isolated MVD, (Pertwee, 1992) and guinea pig ileum, it inhibited electrically evoked twitch responses (Pertwee, 1995). Moreover, anandamide was shown to decrease intraocular pressure in rabbits (Pate, 1995), to reduce sperm-fertilizing capacity in sea urchins by inhibition of the acrosome reaction (Schuel, 1994), and to produce hypotension in rats (Varga, 1995). 

Mature males given weekly intraperitoneal injections of 20 or 50 mg Pb/kg BW as lead acetate for 6 weeks vs. 20 or 50 mg sodium acetate/kg BW as controls Dose-dependent increases in blood and sperm lead concentrations. Serum testosterone levels reduced in lead-exposed rats, possibly from generation of reactive oxygen species, and resulting in premature acrosome reaction and reduced sperm oocyte-penetrating capability 39... 

Clapper, D.L., J.A. Davis, PJ. Lamothe, C. Patton, and D. Epel. 1985a. Involvement of zinc in the regulation of pH, motility, and acrosome reactions in sea urchin sperm. Jour. Cell Biol. 100 1817-1824. 

Fertilization is the fusion of the sperm and ovum. The sperm head binds to the plasma membrane of the egg (oolemma), and the entire spermatozoon enters the cytoplasm of the ovum. Only capacitated spermatozoa with intact acrosomes can enter and pass through the cumulus oophorus. The acrosome is a membrane-bound, cap-like structure covering the anterior portion of the sperm nucleus. The acrosomal reaction is the release of materials that lyse the glycoprotein coat (zona pellucida) surrounding the ovum. This is necessary for fertilization to take place. Before undergoing the acrosomal reaction, sperm go through a type of hypermotility called hyperactivation. The... 

The acrosome reaction is the loss of the acrosomal and plasma membranes in the acrosome region and the release of acrosin, hyaluronidase and other enzymes that disperse the cumulus complex and allow the sperm to penetrate the zona pellucida. After capacitation and the acrosome reaction, sperm penetrate the extracellular cumulus matrix and bind with zona protein 3, a heavily glycosylated protein of the zona pellucida. The first segment of the sperm to make contact with the oolemma is usually the inner acrosomal membrane, followed by the postacrosomal region. The plasma membrane of the sperm attaches to microvilli on the oolemma. Sperm-egg fusion is apparent from reduced movement of the sperm tail (Yanagimachi, 1970,1988 Takano et al.,... 

Sperm evaluations routinely include data on sperm number, morphology and motility (Berman etal., 1996). Testicular spermatid count or cauda epididymal weight are other useful measures of sperm production, but no surrogate measures are adequate to evaluate sperm morphology or motility. A number of other indices of sperm function have been employed (e.g., sperm-zona interactions, acrosome reaction, sperm swelling studies), but these have been of limited utility and infrequently used and have not been incorporated into any testing guidelines. 

Alves, A. P., Mulloy, B., Diniz, J. A., and Mourao, P. A. (1997). Sulfated polysaccharides from the egg jelly layer are species-specific inducers of acrosomal reaction in sperms of sea urchins. ]. Biol. Chem. 272, 6965-6971. 

There is considerable evidence that calcium acts as a primary trigger for egg maturation and fertilization in several phyla. Calcium regulation has been demonstrated or suggested for numerous specific events in fertilization, including sperm motility, the acrosome reaction, sperm-egg binding and fusion and metabolic activation of egg, etc. However, very little is known concerning the mechanisms whereby calcium exerts its effects. 

While acrosin has been localized to the acrosome, there are conflicting reports as to exactly where in the acrosomal compartment acrosin is localized before the acrosome reaction and the timing of its release in the fertilization process. From the description of acrosin as a ZP binding lectin, acrosin must be available to bind the ZP, and this would place the molecule on the surface of the intact sperm, or in some species, of the aerosome-reacted sperm. In the mouse, only acrosome intact sperm bind the ZP (66). Once the sperm has undergone the acrosome reaction and the outer membranes (limiting... 

Trevino, C.L., De la Vega-Beltran, J.L., Nishigaki, T, Eelix, R., and Darszon, A. 2005. Maitotoxin potently promotes Ca(2+) influx in mouse spermatogenic cells and sperm, and induces the acrosome reaction. J Cell Physiol, Epub. 

Skiba-Lahiani M, Auger J, Terribile J, Fattal E, Delattre J, Puisieux F, Jouannet P (1995) Stimulation of movement and acrosome reaction of human spermatozoa by PC12 liposomes encapsulating ATP. Int J Androl 18 287-294... 

Within an ecotoxicological perspective, mammalian methods cannot be extrapolated automatically to other species. Sperm of teleosts, for example, differs in a few very important aspects from that of mammals. Unlike mammalian sperm it is not motile on ejaculation and attains motility only on contact with water. After activation it only moves for a few minutes (for freshwater fish typically around 1 min). Furthermore it enters the egg via the micropyle rather than through an acrosomal reaction. The first minute after the start of motility is therefore crucial to its success in fertilizing an egg, and even when it is deposited on the egg s surface it still has to move fast enough in the right direction to reach the micropyle. Clearly the fertilizing ability of fish sperm is very dependent on its motility, and any pollutant that decreases this movement may be expected to affect fertilization. 

Chang MC, Berkery D, Schuel R, Laychock SG, Zimmerman AM, Zimmerman S, Schuel H (1993) Evidence for a cannabinoid receptor in sea urchin sperm and its role in blockade of the acrosome reaction. Mol Reprod Dev 36 507-516... 

Schuel H, BerkeryD, Schuel R, Chang MC, Zimmerman AM, Zimmerman S (1991) Reduction of the fertilizing capacity of sea urchin sperm by cannabinoids derived from marihuana. 1. Inhibition of the acrosome reaction induced by egg jelly. Mol Reprod Dev 29 51-59... 

Schuel H, Goldstein E, Mechoulam R, Zimmerman AM, Zimmerman S (1994) Anandamide (arachidonylethanolamide), a brain cannabinoid receptor agonist, reduces sperm fertilizing capacity in sea urchins by inhibiting the acrosome reaction. Proc Natl Acad Sci USA 91 7678-7682... 

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