This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Holt, W. V. Articles by North, R. D. Search for Related Content PubMed Articles by Holt, W. V. Articles by North, R. D.

Thermotropic phase transitions in the plasma membrane of ram spermatozoa

Summary. A steady-state fluorescence polarization technique, using the membrane probe 1,6-diphenyl-1,3,5-hexatriene (DPH), showed that separately detectable transitions occurred in the regions of 17, 26 and 36°C in isolated preparations of ram sperm plasma membrane. An independent technique based on the temperature-related behaviour of calcium- and magnesium-activated ATPase detected a single phase transition in the region of 24°C. Modulation of ATPase by neighbouring lipid composition was inferred from findings that phospholipase A₂ caused significant stimulation of the enzyme. Cholesterol-rich liposomes caused an upward shift of the phase-transition temperature from 24°C to 30°C, but the reasons for this are unclear.

It is considered that these phase transitions may have profound effects on sperm survival and physiology, both during normal fertilization processes and in response to cryostorage.

This article has been cited by other articles:

				J.V. Ricker, J.J. Linfor, W.J. Delfino, P. Kysar, E.L. Scholtz, F. Tablin, J.H. Crowe, B.A. Ball, and S.A. Meyers Equine Sperm Membrane Phase Behavior: The Effects of Lipid-Based Cryoprotectants Biol Reprod, February 1, 2006; 74(2): 359 - 365. [Abstract] [Full Text] [PDF]

				P.S. James, C.A. Wolfe, A. Mackie, S. Ladha, A. Prentice, and R. Jones Lipid dynamics in the plasma membrane of fresh and cryopreserved human spermatozoa Hum. Reprod., July 1, 1999; 14(7): 1827 - 1832. [Abstract] [Full Text] [PDF]

				Y. Si Hyperactivation of Hamster Sperm Motility by Temperature-Dependent Tyrosine Phosphorylation of an 80-kDa Protein Biol Reprod, July 1, 1999; 61(1): 247 - 252. [Abstract] [Full Text]

				K Muller, T Pomorski, P Muller, and A Herrmann Stability of transbilayer phospholipid asymmetry in viable ram sperm cells after cryotreatment J. Cell Sci., January 1, 1999; 112(1): 11 - 20. [Abstract] [PDF]

				C. A. Wolfe, P. S. James, A. R. Mackie, S. Ladha, and R. Jones Regionalized Lipid Diffusion in the Plasma Membrane of Mammalian Spermatozoa Biol Reprod, December 1, 1998; 59(6): 1506 - 1514. [Abstract] [Full Text]

				B. Gadella, T. Gadella, B Colenbrander, L. van Golde, and M Lopes-Cardozo Visualization and quantification of glycolipid polarity dynamics in the plasma membrane of the mammalian spermatozoon J. Cell Sci., January 8, 1994; 107(8): 2151 - 2163. [Abstract] [PDF]