Movement of sea urchin sperm flagella.

Abstract

The motion of the sea urchin sperm flagellum was analyzed from high-speed cinemicrographs. At all locations on the flagellum the transversal motion and the curvature were found to vary sinusoidally in time. The curvatures of the flagella increase strongly near the proximal junction. Two sperm are described in transient from rest to normal motion. The full wave motion developed in both sperm within 40 ms.KEY WORDS sea urchin sperm 9 flagellum motion high-speed film -transientsIn recent years the understanding of the forceproducing mechanisms in sea urchin sperm flagella has advanced greatly. A sliding filament mechanism, in which cross bridges between the longitudinal fibers are formed by the dynein arms, has been shown to operate in these flagella (23, 10). The molecular understanding of the force-producing mechanisms has led several investigators to develop theoretical models for the processes that control and coordinate the attachment and breakage of the dynein cross bridges (3,4,16,17,19,21). The aim of these models is to reproduce the characteristics of the flagellar movements from an equation of motion that contains a prescription for the attachment and detachment of the dynein cross bridges. The somewhat surprising situation exists, however, that a detailed description of the sea urchin sperm flagellar motion has not been presented in the literature. The best data available are from "multiple flash" photographs (1, 6), in which three to five positions of a flagellum are registered on a single still frame. The time interval between the successive positions is of the order of one full period of the flagellar beat. The shape of the flagellar wave is well shown in these photographs, but the time resolution is not sufficient to provide an accurate description of the course of events within a cycle of the flagellar beat. In this paper a description of the motion of the sea urchin sperm flagellum is given, based on data from high-speed cinemicrographs at 400 frames/s. The filming speed was made possible by the application of a very highqntensity illumination of the specimens. MATERIALS AND METHODS Experimental MethodsSea urchins (Arbacia and Lytechinus) were obtained from N.E. Marine Supply Co. (Woods Hole, Mass.) (Arbacia) and Pacific BioMarine Laboratories, Inc.(Venice, Calif.) (Lytechinus). Sperm shedding was induced by injecting the sea urchins with 1-2 ml of 0.5 M KCt. The spermatozoa were collected and suspended in artificial seawater (Aquarium Systems, Inc., Eastlake, Ohio) to a concentration of approx. 2 x 107/ml. Several hundred sea urchin eggs were added per milliliter of the suspension to prolong the life of the sperm. When the spermatozoa were stored at room temperature, their motility in the suspension was, by visual estimate, approximately constant for a period of several hours. The pH of the artificial seawater was kept at 7.9. All specimen handling and observations were carried out at a room temperature of 22 _+ I~ A few drops of sperm suspension were placed on a microscope slide and co...

Progression of Flagellar Stages during Artificially Delayed Motility Initiation in Sea Urchin Sperm

“…4 of Goldstein, 1979); similar starting transients have been described by tracings of one spermatozoon at normal pH (Fig. 11 of Rikmenspoel, 1978). Thus, our findings indicate more evidently that the ability of autonomous P bend generation at and propagation from a portion of the axoneme is not exclusively possessed by the very basal region but can be unmasked throughout a wider region when the R bend is suppressed.…”

“…Starting and stopping transients of motility and the transition between different states of activity have been investigated to functionally dissect these interactions (Miller, and Brokaw, 1970;Rikmenspoel, 1978;Goldstein, 1979;Gibbons and Gibbons, 1980b;Baba and Mogami, 1987a). Sea-urchin sperm cells are stored in a quiescent state in the gonads, but upon release into seawater, flagellar motility is initiated, and a 50-fold activation of respiration occurs (Christen et al ., 1982(Christen et al ., , 1983.…”

High-throughput lensfree 3D tracking of human sperms reveals rare statistics of helical trajectories

“…Conventional microscopes equipped with high-magnification objective lenses and high-frame-rate cameras can only meet these requirements for imaging sperms along a 2D plane, which can infer limited information on their natural 3D motion (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). Estimation of the 3D trajectories of sperms from their 2D observations can also be feasible in some cases by assuming a known swimming pattern (15,29).…”

“…Partly due to this low throughput and the limited spatial and temporal sampling windows that conventional microscopes provide, natural 3D swimming patterns of human sperms and their statistics could not be reported so far. Earlier results (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) that were obtained using lens-based conventional microscopes either measured the 2D trajectories of the human sperms along a focal plane, or reported on sperms of other species such as sea urchin, which were significantly easier to resolve under a microscope since their 3D rotation diameter is larger (>13 μm) together with a lower rotation frequency compared to human sperms.…”

Application of a numerical simulation to improve the separation efficiency of a sperm sorter

“…Various flagellar [12][13][14] models have been proposed as models for sperm motion. Since the progressive velocity and the amplitude of sperm motion are important from the viewpoint of investigating the separation efficiency of motile sperm, the present study models sperm motion as a simple sinusoidal wave, as shown in Fig.…”