Motility of spermatozoa at surfaces.

نویسنده

  • D M Woolley
چکیده

The hydrodynamic basis for the accumulation of spermatozoa at surfaces has been investigated. The general conclusion is that when spermatozoa arrive at a surface, they will remain there if the vector of the time-averaged thrust is directed towards that surface. This can arise in two basic ways. First, consider spermatozoa that maintain a three-dimensional waveform and roll (spin) as they progress: in this case, it is argued that the conical (rather than cylindrical) shape of the flagellar envelope will establish the direction-of-thrust necessary for capture by the surface. (Additional findings, for spermatozoa of this type, are that the swim-trajectory is curved and that the direction of its curvature reveals the roll-direction of the cell.) Second, consider spermatozoa that maintain a strictly two-dimensional waveform at the surface: in this case, spermatozoa can be captured because the plane-of-flattening of the sperm head is tilted slightly relative to the plane of the flagellar beat. The sperm head is acting as a hydrofoil and, in one orientation only, it comes to exert a pressure against the surface. (This pressure may possibly, in vivo, aid the penetration of the zona pellucida.) The hydrofoil action of sperm heads may explain any bias in the circling direction of spermatozoa that execute two-dimensional waves at surfaces. Finally, a more complex phenomenon is where interaction of the spermatozoa with the surface appears to induce a three-dimensional to two-dimensional conversion of the flagellar wave (thus permitting the hydrofoil effect described). This is characteristic of sperm with 'twisted planar' rather than helical waves. In mammalian spermatozoa, approximately half the beat cycle is planar and the other half generates a pattern of torque causing the head to roll clockwise (seen from ahead), producing a torsion of the neck region of the flagellum. It is the gradual suppression of this torsion, by either impedance at the solid boundary or by raised viscosity, that converts the 'twisted planar' shape into a planar wave.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Cryopreservation of Mesopotamian catfish (Silurus triostegus H., 1843) spermatozoa: Effects of diluents and osmotic pressure on spermatozoa DNA damage, rate and duration of motility

This study was performed to evaluate the effectiveness of three different conditions of osmotic pressure (325, 365 and 385 mOsm kg-1) in combination with dimethyl sulfoxide (DMSO) and NaCl or glucose on spermatozoa DNA damage, rate and duration of motility. Sperm was collected from eight healthy mature Mesopotamian catfish, evaluated microscopically and pooled at 25 °C. The pooled sperm samples...

متن کامل

Formation of Hydrogen Peroxide by Chilled Goat Spermatozoa and the Effects of Dead Spermatozoa on Motility Characteristics

In this study, the formation of hydrogen peroxide (H2O2) by chilled goat spermatozoa was measured. Furthermore, the effects of dead spermatozoa on motility characteristics were studied. Fresh collected ejaculates from five Shami bucks were centrifuged and virtually all seminal plasma was removed. A part of the collected spermatozoa was killed by two ways: the first by repe...

متن کامل

P-119: In Vitro Assessment of Sucrose for Preservation of Buffalo Epididymal Spermatozoa

Background: Epididymal spermatozoa have been used for production of offspring from genetically important animals after they are dead. To attain optimal fertility with epididymal spermatozoa, they should be preserved in a suitable medium in 37°C. Preservation media provides requirement for spermatozoa and affects its motility, viability, and fertility. Sucrose is one of the important components ...

متن کامل

The effect of platelet activating factor on the motility and acrosome reaction of ram spermatozoa

Platelet activating factor (PAF) is a novel signaling phospholipids that in addition to platelet activation has many biological properties. The acrosome reaction, as an essential step in mammalian fertilization, can occur in response to several agents such as PAF. Therefore, the present study aimed to assess the effect of PAF on the motility and acrosome reaction of ram spermatozoa. Semen was c...

متن کامل

Effects of storage duration at 5 ºC and type of cryoprotectant on cooled and frozen-thawed ram epididymal spermatozoa

Freezing of ejaculated and epididymal spermatozoa is currently a subject of interest with the purpose of establishing an efficient gene banking model for valuable animals or endangered species. Therefore, the present study evaluated the influence of different storage duration )0, 1.5 and 5 h) at 5 ºC and type of cryoprotectant on freezability of ram epididymal spermatozoa. With increasing the s...

متن کامل

Sperm characteristics in Grass carp, Ctenopharyngodon idella effect of ions on spermatozoa motility and fertilization capacity

In this study, sperm characteristics (motility parameters and ionic composition of seminal plasma) and effect of ions on motility (duration of motility of sperm and percentage of motile spermatozoa) and fertilization capacity (fertilization rate, hatching rate, survival rate and larvae length) were investigated in Ctenopharyngdon idella. The longest duration of motility obtained in solution con...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Reproduction

دوره 126 2  شماره 

صفحات  -

تاریخ انتشار 2003