Motility is a characteristic function of the male gamete, which allows spermatozoa to actively reach and penetrate the female gamete in organisms with internal and external fertilization. Sperm motility is acquired under the control of many extrinsic and intrinsic factors and is based on a specialized structure of the sperm flagellum called "axoneme". An overview of how the sperm flagellum is organized, and it operates to support cell motility is presented, with special focus on the molecular mechanisms and factors involved in the development, maintenance and control of motility. Data obtained in aquatic organisms with external fertilization, such as sea urchins, ascidians or fishes are critically analyzed because they constitute model species on which most of the present day understanding of sperm motility function is based. In most animal species, sperm motility is dependent on a long appendage called flagellum. Flagella are essential organelles found in most eukaryotic cells; their basic structure is the axoneme, which consists of a scaffold of microtubules and is responsible for movement in an autonomous manner if ATP-energy is present. Flagellar beat propels the cell through the medium which surrounds sperm cells and is responsible of the translational drive of spermatozoa. The present paper includes: (1) an introduction to typical sperm morphology and ultrastructure in most aquatic species, (2) the motility apparatus or axoneme of the spermatozoa: the axoneme, (3) the structural and biochemical composition of the axoneme, (4) the axonemal motor or dynein, and its operation, (5) the regulation of motility at axoneme and cell membrane levels, including several effectors such as Ca2+ ions, (6) biophysical features of the wave propagation mechanism in motile spermatozoa, (7) the energy production and consumption, and (8) the building of a flagellum. Flagellar beating in aquatic animals is illustrated using several examples in figures and video-clips. These types of data are also used for computer simulation of various aspects of the modulation of sperm motility of marine animals.
Sexually mature males (BW = 1600 ± 150 g and TL = 235 ± 30 mm) of northern pike (Esox lucius L.) were randomly selected from a pond to record changes in their sperm quality parameters (spermatozoa morphology, sperm volume, density, and motility parameters) during the spawning season. The morphological and motility parameters changed significantly during the reproductive season with following trends. Only, head width was not changed during the spawning season. The longest spermatozoa and its flagellar length were found at the middle of spawning period (TL = 38.24 ± 0.37 μm and 35.14 ± 0.26 μm) and shortest at the beginning of spawning period (TL = 34.81 ± 0.29 μm and 32.53 ± 0.18 μm). Other morphological characters were always the lowest at the beginning of spawning period. Sperm volume was changed from 0.33 ± 0.3 ml in February, 0.43 ± 0.2 ml in March to 0.24 ± 0.1 ml in April, and density from 16.2 ± 0.2 × 109 spermatozoa ml-1 in February, 19.4 ± 0.2 × 109 spermatozoa ml-1 in March to 4.8 ± 0.2 × 109 spermatozoa ml-1 in April. Same sperm velocity was observed in all spawning terms at 10 and 20 s after activation. Higher velocity was found at 30 and 40 s after activation in sperm collected at the middle and the end of spawning period. Significantly, higher percentage of motile sperm was observed at 20, 30, and 40 s after activation in sperm sampled at the end of spawning period. This study supports the hypothesis that longer spermatozoa swim faster.
- MeSH
- analýza spermatu veterinární MeSH
- Esocidae anatomie a histologie růst a vývoj fyziologie MeSH
- motilita spermií * MeSH
- roční období MeSH
- rozmnožování MeSH
- sexuální chování zvířat * MeSH
- spermatogeneze * MeSH
- spermie fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
