Dynamics of flagellar force generated by a hyperactivated spermatozoon

Ishijima, Sumio

doi:10.1530/rep-10-0445

Cited by 39 publications

(37 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By using the mZP oscillatory spherical net model in our numerical experiments, we have come to the conclusion that sharp angles are more favorable, particularly π/4 and combinations π/4 and π/12 or π/4 and π/6. In addition to the findings in [40] and our own results, we consider that a lateral contact, i.e. sharp impact angle of spermatozoid collision, provides a larger contact surface between the spermatozoid and ZP which may facilitate receptor recognition between the two contact surfaces leading to a potentially easier penetration mediated predominantly by biochemical mechanisms.…”

Section: The Results and Discussionsupporting

confidence: 63%

“…There are articles where it is pointed that the transversal force generated by a spermatozoid is higher than the propulsive force [40,41] indicating that a sharp angle would be more favorable for the penetration. By using the mZP oscillatory spherical net model in our numerical experiments, we have come to the conclusion that sharp angles are more favorable, particularly π/4 and combinations π/4 and π/12 or π/4 and π/6.…”

Section: The Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of sperm impact angle on successful fertilization through mZP oscillatory spherical net model

Hedrih

Lazarević

Mitrovic-Jovanovic

2015

Computers in Biology and Medicine

View full text Add to dashboard Cite

Section: The Results and Discussionsupporting

confidence: 63%

Section: The Results and Discussionmentioning

confidence: 99%

Influence of sperm impact angle on successful fertilization through mZP oscillatory spherical net model

Hedrih

Lazarević

Mitrovic-Jovanovic

2015

Computers in Biology and Medicine

View full text Add to dashboard Cite

“…When hyperactivated sperm are immobilized by adhering to a surface, the bending of the midpiece region just proximal to the sperm head can be extremely severe resulting in strong lateral force exerted by the sperm head. Strong lateral movement of the sperm head during hyperactivation has been shown to be important in penetration of the zona pellucida (Ishijima, 2011). Ho et al (2009 showed that the head pivoting motion that accompanies the asymmetric beating in the early stages of beating is necessary for the sperm to detach from the sperm reservoir in the isthmus of the oviduct and also for entry into the upper oviduct.…”

mentioning

confidence: 99%

Functional anatomy of the mammalian sperm flagellum

2016

View full text Add to dashboard Cite

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 1 2 arrangement of microtubule doublets and hundreds of accessory proteins that together constitute an axoneme. However, they also possess several characteristic peri-axonemal structures that make the mammalian sperm tail function differently. These modifications include nine outer dense fibers (ODFs) that are paired with the nine outer microtubule doublets of the axoneme, and are anchored in a structure called the connecting piece located at the base. The presence of the ODFs and connecting piece, and the absence of a basal body, dictate that physical forces generated by the dynein motors are transmitted to the base of the flagellum through the ODFs. Mammalian sperm flagella also possess a mitochondrial and a fibrous sheath that encircle most of the axoneme. These sheaths and the ODFs add mechanical rigidity to the flagellum creating the functional effect of increasing bend wavelength, which requires the entrainment of more dynein motors in the production of a single wave. The sheaths also act as a retinaculum and maintain the integrity of the central axoneme when large bending torques are generated by dynein. Large torque production is crucial to the process of hyperactivation and the unique motility transitions associated with effective fertilizing capacity. Consequently, these specialized anatomical features are essential for the effective interaction of sperm with the female reproductive tract and ovum. V C 2016 Wiley Periodicals, Inc.Key Words: axoneme; outer dense fibers; fibrous sheath; outer doublets; dynein; connecting piece; hyperactivation; sperm motility Introduction E ukaryotic cilia and flagella are highly conserved and ubiquitous organelles present in most animals, as well as many lower plants and eukaryotic protozoa. In the vertebrate lineage, the eukaryotic flagellum is universally employed to propel the male gamete. In the mammalian branch of the vertebrates, the sperm tail is always a modified flagellum with some characteristic accessory features that are added onto the basic 9 1 2 axoneme of microtubules found in most cilia and flagella. Figure 1 shows transmission electron micrographs (TEMs) of a mouse sperm flagellum in cross section at several positions along the length of the flagellum. The central axoneme is visible with its nine outer doublets surrounding a pair of single central microtubules (central pair or CP). Each of the outer microtubule doublets bears two rows of projections called the inner row and outer row of dynein arms. These arms are composed of the dynein motor proteins that power motility. The dynein arms are the source of the motive force that bends the flagellum. The dynein heavy chains (DHC) of the arms form bridges between the outer doublets and undergo a Mg-ATP driven power stroke that generates a sliding (or shearing) action between t...

show abstract

“…From the computed time-averaged translation and rotation of an egg, the force and torque exerted by the single spermatozoon can be obtained using Stokes’s law of drag. The force and torque by sperm swimming on the zona have been estimated in various species and different settings212223. Our computational method also follows these literatures, but is based on a more accurate numerical scheme.…”

Section: Methodsmentioning

confidence: 99%

The mechanics clarifying counterclockwise rotation in most IVF eggs in mice

Ishimoto

Ikawa

Okabe

2017

Sci Rep

View full text Add to dashboard Cite

In mammalian fertilization, a small spermatozoon interacts with an egg that is a few thousand times larger in volume. In spite of the big difference in size and mass, when spermatozoa are bound to eggs, they begin rotating the eggs in in vitro observation. This was dubbed the ‘fertilization dance’. Interestingly, some papers reported that the rotation was counterclockwise, although the reason for this skewed rotation was not clarified. We focused on a chirality of helical beating of spermatozoa and found that eggs rotate counterclockwise in simulations under a certain geometrical condition where the eggs were situated. This theory of egg rotation was validated by demonstrating egg rotation in a clockwise direction by floating eggs to the upper surface of the IVF medium. The enigma of skewed rotation of IVF eggs was clarified.

show abstract

Dynamics of flagellar force generated by a hyperactivated spermatozoon

Cited by 39 publications

References 32 publications

Influence of sperm impact angle on successful fertilization through mZP oscillatory spherical net model

Influence of sperm impact angle on successful fertilization through mZP oscillatory spherical net model

Functional anatomy of the mammalian sperm flagellum

The mechanics clarifying counterclockwise rotation in most IVF eggs in mice

Contact Info

Product

Resources

About