Capacitation

Capacitation

:"This article is about a biological process related to reproduction; for the other use, see Capacitation (NGO)."

Capacitation is the penultimate [Essential Reproduction, Johnson, 6th edition, Blackwell Publishing] step in the maturation of mammalian spermatozoa and is required to render them competent to fertilize an oocyte.This step is a biochemical event; the sperm move normally and look mature prior to capacitation."" this step typically occurs after ejaculation, in the female reproductive tract."", capacitation can occur in sperm that have either undergone ejaculation or have been extracted from the epididymis.

By secreting sterol binding albumin, lipoproteins, proteolytic and glycosidasic enzymes such as heparin, the uterus aids in the steps of capacitation.

Non-mammalian spermatozoa do not require this capacitation step and are ready to fertilize an oocyte immediately after release from the male. After this capacitation the sperm must undergo activation involving the acrosome reaction.

Result of capacitation

Capacitation involves the destabilisation of the sperm head membrane rendering it more fusigenic. This change is facilitated by the removal of sterols (e.g. cholesterol) and non-covalently bound epididymal/seminal glycoproteins. The result is a more fluid membrane with an increased permiability to Ca2+.

An influx of Ca2+ produces increased intracellular cAMP levels and thus, an increase in motility. Hyperactivation is also part of capacitation and is the result of the increased Ca2+ levels. The enzyme FPP (fertilization promoting factor) produced by the male is essential for capacitation.

Discovery

The discovery of this process was independently reported in 1951 by both Min Chueh Chang [Chang, M. C. (1951) “Fertilizing capacity of spermatozoa deposited into the fallopian tubes,” "Nature", vol. 168, pages 697-698.] and Colin Russell Austin [Austin, C. R. (1951) “Observations of the penetration of sperm into the mammalian egg,” "Australian Journal of Scientific Research", Series B, vol. 4, pages 581-596.] [Austin, Colin Russell: obituary: “Colin Austin,” "Australian Academy of Science Newsletter", No. 60, page 11 (August-November 2004). Available on-line at: http://www.science.org.au/newsletters/aas60.pdf .] .

Historically, the term "capacitation" has evolved in meaning and this should be taken into account when consulting sources.

ee also

*Cortical reaction
*Acrosome reaction

Footnotes

References

* Beaudin, Stacey; Kipta, Donna; and Orr, Annamarie. (October 9, 1996). [http://www.ucalgary.ca/UofC/eduweb/virtualembryo/capacitation.html Current research into sperm capacitation: An Essay on Visconti, et al. Development 121: 1129-1150 (1995)] . Verified availability 2005-04-06.
* Visconti, Pablo E.; Bailey, Janice L.; Moore, Grace D.; Pan, Dieyun; Olds-Clarke, Patricia; and Kopf, Gregory S. (1995). Capacitation of mouse spermatozoa: I. Correlation between the capacitation state and protein tyrosine phosphorylation. "Development" 121, 1129-1137. PMID 7743926. full article text available on-line

External links

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Look at other dictionaries:

  • capacitation — capacitation. См. капацитация. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • capacitation — [ kapasitasjɔ̃ ] n. f. • 1974; mot angl. ♦ Biol. Transformation du spermatozoïde qui lui donne son pouvoir fécondant …   Encyclopédie Universelle

  • Capacitation — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Sur les autres projets Wikimedia : « Capacitation », sur le Wiktionnaire (dictionnaire universel) Capacitation peut être :… …   Wikipédia en Français

  • capacitation — noun Date: 1951 the change undergone by sperm in the female reproductive tract that enables them to penetrate and fertilize an egg …   New Collegiate Dictionary

  • capacitation — n. [L. capax, roomy] 1. Cause to become capable; qualify. 2. In spermatogenesis, the physiological changes between insemination and fertilization …   Dictionary of invertebrate zoology

  • capacitation — A process occurring in mammalian sperm after exposure to secretions in the female genital tract. Surface changes take place probably involved with the acrosome which are necessary before the sperm can fertilize an egg …   Dictionary of molecular biology

  • capacitation — See capacitate. * * * …   Universalium

  • capacitation — noun a) Enablement. b) The process of altering sperm to allow them to fertilize eggs. , Chinese: Mandarin …   Wiktionary

  • capacitation — C. is a process whereby the glycoprotein coat is modified and seminal proteins are removed from the surface of the sperm. There are no morphologic changes. C. occurs in in vitro fertilization; after c., the acrosomal reaction can occur. [L.… …   Medical dictionary

  • capacitation — n. accommodation; act of giving capacitance; process by which spermatozoa becomes able to fertilize an egg (Biology) …   English contemporary dictionary

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