Motility of the spermatozoa of rainbow trout, Salmo gairdneri, in solutions of various salinities as studied by quasi-elastic light scattering

Quasi-elastic light scattering (QELS) was used to study the motile properties of rainbow trout spermatozoa. It was possible to make motility evaluations at 10-sec intervals and to use the time course of these evaluations to study the effect of various concentrations of NaCl on motility. Concentrations of approximately 5% by weight were found to best prolong active swimming. Also, it was found that the motility of undiluted samples could be initiated after storage at 4 degrees C for at least 24 h.

Motility analysis of circularly swimming bull spermatozoa by quasi-elastic light scattering and cinematography

The Rayleigh-Gans-Debye approximation is used to predict the electric field autocorrelation functions of light scattered from circularly swimming bull spermatozoa. Using parameters determined from cinematography and modeling the cells as coated ellipsoids of semiaxes a = 0.5 micrometers, b = 2.3 micrometers, and c = 9.0 micrometers, we were able to obtain model spectra that mimic the data exactly. A coat is found to be a necessary attribute of the particle. It is also clear that these model functions at 15 degrees may be represented by the relatively simple function used before by Hallett et al. (1978) to fit data from circularly swimming cells, thus giving some physical meaning to these functional shapes. Because of this agreement the half-widths of experimental functions can now be interpreted in terms of an oscillatory frequency for the movement of the circularly swimming cell. The cinematographic results show a trend to chaotic behavior as the temperature of the sample is increased, with concomitant decrease in overall efficiency. This is manifested by a decrease in oscillatory frequency and translational speed.

Half-width scaling of electric field autocorrelation functions of light scattered from bull spermatozoa

The half-width scaling of experimental and model electric field autocorrelation functions of light scattered from normally swimming, defectively swimming, and immotile bull spermatozoa is examined. It is found that a scatter of size 9.0 x 2.3 x 0.45 micrometers is most appropriate for this Rayleigh-Gans-Debye ellipsoid model. In the case of the immotile cells, this model correctly predicts the features seen in the scaling data as well as the absolute value of the data. For the normally swimming and defective populations the model proves to predict correctly the features seen in experimental scaling curves, but not the absolute value of the data. This discrepancy appears to be related to a lack of detail in the model, since the agreement is poorest at large scattering angles.

Scaling properties of light scattering spectra for particles moving with helical trajectories

This investigation indicates that model quasi-elastic light scattering spectra from particles moving on a helical trajectory exhibit nonscaling behavior. At low q light scattering samples the average progressive speed of the center of mass, while at large q it is the trajectory speed which is important. The extent of this non-scaling depends critically on the pitch and radius of the helix. For spherical scatterers the largest effect is seen when the ratio of the pitch to the radius is ~0.1. Interpreting data from such a system by using a point particle approximation would lead to a sizable underestimate of the speed of the scatterer. In the high q limit the scaling level of the model correlation functions is independent of the product of the curvature of the helix and q. The results for rotating disk-shaped ellipsoidal scatterers parallel those for spheres. The critical parameter for cases where the radius of the disk is large compared with the radius of the helix is the radius of the disk itself. When the radius of the disk is larger than the wavelength of the light the scaling behavior is determined primarily by rotational motion. Deviation from this behavior due to helical motion occurs only at extremely low values of q.

Quasi-elastic light-scattering spectra of swimming spermatozoa. Rotational and translational effects

The electric field autocorrelation functions of light scattered from normal swimming bull spermatozoa are shown to be dependent on the mean head rotation frequency and not on the translational speed of the cells, as previously believed. This result was obtained from numerical generation of functions in which spermatozoa were modeled as Rayleigh-Gans-Debye ellipsoids having semiaxes a = 0.5 micrometer, b = 2.3 micrometer, and c = 9.0 micrometer. The magnitude of c required to achieve agreement with the experimental data is larger than the half-length of the head region of the cell. This implies that the midpiece, which also lies along c, contributes to the scattering power. Details regarding swimming trajectory and head orientation are included in the model. Analyses of the calculated functions and comparisons with experimentally determined ones suggest that at a scattering angle of 15 degrees the electric field autocorrelation function can be fit a simple Lorentzian whose half-width is inversely proportional to the scattering vector and the mean head rotational frequency.

Swimming speed distributions of bull spermatozoa as determined by quasi-elastic light scattering

88 semen samples from 39 bulls have been investigated by the quasi-elastic light scattering technique. Normal, defective, and dead cells each yielded characteristic autocorrelation functions. The form of these functions indicates that the swimming speed distribution of normal cells is a gamma distribution with two degrees of freedom while that for defective or circular swimmers is a gamma distribution with one degree of freedom. The resulting analysis of the experimental autocorrelation functions yields the fraction of the sample that is normal, the fraction that is defective, and the average speed of each group. The average helical swimming speed of normal cells was found to be 384 micron/s, while the average trajectory speed of the circular swimmers was found to be 103 micron/s. The overall quality of the semen samples as determined by light scattering is compared to quality determination on the same samples by technicians from the artificial insemination industry.