HWN Suggests

Keeping sperm cells on track

One of the most specialized functions of microtubules is found in the sperm tail or flagellum. Sperm flagella are essential for male fertility and thus for sexual reproduction. They have to beat in a very precise and coordinated manner to allow progressive swimming of the spermatozoids, and failure to do so can lead to male infertility. To keep sperm swimming in a straight line, the modification of the protein tubulin by enzymes is essential. One modification is called glycylation, and was so far among the least-explored modifications of tubulin.

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 Why Do Sperm Cells Have Flagella

Imagine a tiny swimmer, navigating through the depths of a vast ocean. This is not just any swimmer; it’s a sperm cell, equipped with its own whip-like tail known as a flagellum. But why do these microscopic marvels need such specialized appendages? The answer lies in the intricate dance of reproduction...

Articles of Interest

The Wriggling Wonder: Do Sperm Cells Have Flagella?

This isn't just a decorative feature; it's the engine that powers the sperm's incredible journey. Its primary role is propulsion, allowing the sperm to swim through the female reproductive tract in search of the ovum, the egg. Without this whiplike appendage, the chances of fertilization would be astronomically slim. It's a marvel of biological engineering, designed for a singular, vital purpose.

Functional anatomy of the mammalian sperm flagellum

The eukaryotic flagellum is the organelle responsible for the propulsion of the male gamete in most animals. Without exception, sperm of all mammalian species use a flagellum for swimming. The mammalian sperm has a centrally located 9 + 2 arrangement of microtubule doublets and hundreds of accessory proteins that together constitute an axoneme.

Human sperm steer with second harmonics of the flagellar beat

Sperm are propelled by bending waves traveling along their flagellum. For steering in gradients of sensory cues, sperm adjust the flagellar waveform. Symmetric and asymmetric waveforms result in straight and curved swimming paths, respectively. Two mechanisms causing spatially asymmetric waveforms have been proposed: an average flagellar curvature and buckling. We image flagella of human sperm tethered with the head to a surface. The waveform is characterized by a fundamental beat frequency and its second harmonic

Mammalian sperm flagella and cilia

The sperm flagellum is responsible for the sperm motility, and defects in it often cause male infertility.

Molecular Architecture of the Sperm Flagella: Molecules for Motility and Signaling

As the tails of sperm, flagella comprise the motile apparatus necessary for the movement and penetration of sperm into the egg at fertilization (Fig. 1A, B). They show oscillatory movements at high speed. The motility is generated by the internal cytoskeletal structure called the axoneme, which is a highly organized microtubule-based structure that has been well conserved through evolution

Scientists Caught Sperm Ignoring a Major Physical Law

Highly viscous fluids would typically dissipate a flagellum's energy, preventing a sperm or single-celled algae from moving much at all. And yet somehow, the elastic flagella can propel these cells along without provoking a response from their surroundings. The researchers found that sperm tails and algal flagella have an 'odd elasticity', which allows these flexible appendages to move about without losing much energy to the surrounding fluid.

The synchronicity of sperm motility and zebra stripe formation

The study investigates a fascinating connection between two seemingly unrelated phenomena: sperm swimming and the formation of zebra stripes. Researchers from the University of Bristol have uncovered that the patterns governing the motility of sperm are strikingly similar to the ways that dictate the distinctive stripes on zebra coats.