scholarly journals Dynamics of flagellar force generated by a hyperactivated spermatozoon

Reproduction ◽  
2011 ◽  
Vol 142 (3) ◽  
pp. 409-415 ◽  
Author(s):  
Sumio Ishijima
Keyword(s):  
Zona Pellucida ◽  
High Speed ◽  
Beat Frequency ◽  
Transverse Force ◽  
Sperm Head ◽  
Propulsive Force ◽  
Resistive Force ◽  
High Speed Video ◽  
Sperm Penetration ◽  
Resistive Force Theory

The flagellar force generated by a hyperactivated monkey spermatozoon was evaluated using the resistive force theory applied to the activated (nonhyperactivated) and hyperactivated flagellar waves that were obtained using high-speed video microscopy and digital image processing in order to clarify the mechanism of sperm penetration through the zona pellucida. No difference in the maximum propulsive force, which was parallel to the longitudinal sperm head axis, was found between the activated and hyperactivated spermatozoa. The maximum transverse force (45 pN), which was perpendicular to the longitudinal sperm head axis, of the hyperactivated spermatozoon was ∼2.5 times its propulsive force. As the beat frequency of the flagellar beating remarkably decreased during the hyperactivation, the slowly oscillating transverse force (5 Hz) by the hyperactivated spermatozoon seems to be most effective for sperm penetration through the zona pellucida.

scholarly journals Unlocking the secrets of multi-flagellated propulsion: drawing insights from Tritrichomonas foetus

2014 ◽  
Vol 11 (93) ◽  
pp. 20131149 ◽  
Author(s):  
Scott C. Lenaghan ◽  
Stefan Nwandu-Vincent ◽  
Benjamin E. Reese ◽  
Mingjun Zhang
Keyword(s):  
High Speed ◽  
Experimental Approach ◽  
Flexural Rigidity ◽  
Tritrichomonas Foetus ◽  
Propulsive Force ◽  
High Speed Imaging ◽  
Resistive Force ◽  
Thrust Generation ◽  
Run And Tumble ◽  
Resistive Force Theory

In this work, a high-speed imaging platform and a resistive force theory (RFT) based model were applied to investigate multi-flagellated propulsion, using Tritrichomonas foetus as an example. We discovered that T. foetus has distinct flagellar beating motions for linear swimming and turning, similar to the ‘run and tumble’ strategies observed in bacteria and Chlamydomonas . Quantitative analysis of the motion of each flagellum was achieved by determining the average flagella beat motion for both linear swimming and turning, and using the velocity of the flagella as inputs into the RFT model. The experimental approach was used to calculate the curvature along the length of the flagella throughout each stroke. It was found that the curvatures of the anterior flagella do not decrease monotonically along their lengths, confirming the ciliary waveform of these flagella. Further, the stiffness of the flagella was experimentally measured using nanoindentation, allowing for calculation of the flexural rigidity of T. foetus' s flagella, 1.55×10 −21 N m 2 . Finally, using the RFT model, it was discovered that the propulsive force of T. foetus was similar to that of sperm and Chlamydomonas , indicating that multi-flagellated propulsion does not necessarily contribute to greater thrust generation, and may have evolved for greater manoeuvrability or sensing. The results from this study have demonstrated the highly coordinated nature of multi-flagellated propulsion and have provided significant insights into the biology of T. foetus .

scholarly journals Intracellular Cl− Regulation of Ciliary Beating in Ciliated Human Nasal Epithelial Cells: Frequency and Distance of Ciliary Beating Observed by High-Speed Video Microscopy

2020 ◽  
Vol 21 (11) ◽  
pp. 4052
Author(s):  
Makoto Yasuda ◽  
Taka-aki Inui ◽  
Shigeru Hirano ◽  
Shinji Asano ◽  
Tomonori Okazaki ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
High Speed ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Video Microscopy ◽  
Nasal Epithelial Cells ◽  
Ciliary Beating ◽  
High Speed Video ◽  
Human Nasal Epithelial Cells ◽  
Ciliary Beat

Small inhaled particles, which are entrapped by the mucous layer that is maintained by mucous secretion via mucin exocytosis and fluid secretion, are removed from the nasal cavity by beating cilia. The functional activities of beating cilia are assessed by their frequency and the amplitude. Nasal ciliary beating is controlled by intracellular ions (Ca2+, H+ and Cl−), and is enhanced by a decreased concentration of intracellular Cl− ([Cl−]i) in ciliated human nasal epithelial cells (cHNECs) in primary culture, which increases the ciliary beat amplitude. A novel method to measure both ciliary beat frequency (CBF) and ciliary beat distance (CBD, an index of ciliary beat amplitude) in cHNECs has been developed using high-speed video microscopy, which revealed that a decrease in [Cl−]i increased CBD, but not CBF, and an increase in [Cl−]i decreased both CBD and CBF. Thus, [Cl−]i inhibits ciliary beating in cHNECs, suggesting that axonemal structures controlling CBD and CBF may have Cl− sensors and be regulated by [Cl−]i. These observations indicate that the activation of Cl− secretion stimulates ciliary beating (increased CBD) mediated via a decrease in [Cl−]i in cHNECs. Thus, [Cl−]i is critical for controlling ciliary beating in cHNECs. This review introduces the concept of Cl− regulation of ciliary beating in cHNECs.

Ciliary beat frequency study by high speed video microscopy

2016 ◽  
Author(s):  
Gerardo Vizmanos-Lamotte ◽  
Sandra Rovira ◽  
Alba Torrent ◽  
Antonio Moreno-Galdó
Keyword(s):  
High Speed ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Video Microscopy ◽  
High Speed Video ◽  
Ciliary Beat

scholarly journals Mechanisms and fluid dynamics of foraging in heterotrophic nanoflagellates

2021 ◽  
Author(s):  
Sei Suzuki ◽  
Anders Andersen ◽  
Thomas Kiørboe
Keyword(s):  
High Speed ◽  
Foraging Strategies ◽  
Heterotrophic Nanoflagellates ◽  
Functional Responses ◽  
Ingestion Rates ◽  
Predator Prey ◽  
High Speed Video ◽  
Prey Handling ◽  
Resistive Force Theory ◽  
Prey Searching

ABSTRACTHeterotrophic nanoflagellates are the main consumers of bacteria and picophytoplankton in the ocean. In their micro-scale world, viscosity impedes predator-prey contact, and the mechanisms that allow flagellates to daily clear a volume of water for prey corresponding to 106 times their own volume is unclear. It is also unclear what limits observed maximum ingestion rates of about 104 bacterial prey per day. We used high-speed video-microscopy to describe feeding flows, flagellum kinematics, and prey searching, capture, and handling in four species with different foraging strategies. In three species, prey-handling times limit ingestion rates and account well for their reported maximum values. Similarly, observed feeding flows match reported clearance rates. Simple point-force models allowed us to estimate the forces required to generate the feeding flows, between 4-13 pN, and consistent with the force produced by the hairy (hispid) flagellum, as estimated using resistive force theory. Hispid flagella can produce a force that is much higher than the force produced by a naked flagellum with similar kinematics, and the hairy flagellum is therefore key to foraging in most nanoflagellates. Our findings provide a mechanistic underpinning of observed functional responses of prey ingestion rates in nanoflagellates.

Sperm Penetration of the Zona Pellucida of the Pig Egg

1964 ◽  
Vol 41 (3) ◽  
pp. 603-608
Author(s):  
Z. DICKMANN ◽  
P. J. DZIUK
Keyword(s):  
Zona Pellucida ◽  
Phase Contrast ◽  
Sperm Head ◽  
Narrow Slit ◽  
Penetration Curve ◽  
Phase Contrast Microscope ◽  
Sequence Of Events ◽  
Contrast Microscope ◽  
Sperm Penetration

1. Pig eggs were examined with the ordinary and phase-contrast microscope in search for clues about the process of sperm penetration of the zona pellucida. 2. The following observations were made, (i) The zona pellucida consists of three concentric layers--the inner-zona, the middle-zona, and the outer-zona. (ii) The fertilizing spermatozoon makes a narrow slit in the zona by penetrating through it. The slit has a particular shape referred to as ‘the penetration curve’. (iii) Extra spermatozoa (i.e. spermatozoa other than the fertilizing spermatozoon) enter the zona and follow a course very similar to that of the fertilizing spermatozoon, but they can penetrate it only as far as the middle-zona. Extra spermatozoa have not been observed in the inner-zona, indicating that in this layer the ‘zona reaction’ is normally absolute, (iv) A filament extending from the apex of the sperm head has been observed in spermatozoa embedded in the zona. It is suggested that the sperm path through the zona is determined by this filament, which is therefore termed the sperm-penetration filament (SPF). 3. On the basis of these observations the following sequence of events in the passage of a spermatozoon through the zona is suggested. First, the spermatozoon attaches to the zona; it then ejects into the zona the SPF. The SPF, in turn, guides the spermatozoon on its curved course through the zona.

The Relationship Between Sperm Velocity and Pressures Applied to the Zona Pellucida During Early Sperm-Oocyte Penetration

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Amit Gefen
Keyword(s):  
Zona Pellucida ◽  
Early Phase ◽  
Sperm Quality ◽  
Sperm Head ◽  
Velocity Measurements ◽  
Sperm Velocity ◽  
Important Indicator ◽  
Sperm Penetration ◽  
The Relationship ◽  
Relevant Range

Sperm velocity is long known to be an important indicator of sperm quality but without much biophysical theory explaining it. Contact mechanics based modeling was developed here to determine the effects that sperm velocity (vs) and sperm head density (ρs)—which is an indicator of the stiffness of the head, have on the peak sperm-zona pellucida contact pressure (pm) during the early phase of sperm penetration. The modeling identified vs as being more influential on pm compared with the influence that ρs has, which means that for spermatozoa competing on the same oocyte, greater vs is a more important advantage than higher ρs. Specifically, pm was more sensitive by a power of 2 to changes in vs than to changes in ρs. It was further demonstrated that each 0.1 g/cc increase in ρs (within the physiologically relevant range of 1.3–1.7 g/cc) would be equivalent to just ∼3% rise in vs, indicating again that faster swimming is a better strategy for spermatozoa compared with head stiffening. The modeling hence provided some useful insights regarding sperm biomechanics, which theoretically elucidate the well-recognized importance of sperm velocity measurements as being indicative of sperm quality.

Reproductive characteristics of the african pygmy hedgehog, atelerix albiventris

Reproduction ◽  
2000 ◽  
pp. 143-150 ◽  
Author(s):  
JM Bedford ◽  
OB Mock ◽  
SK Nagdas ◽  
VP Winfrey ◽  
GE Olson
Keyword(s):  
Fallopian Tube ◽  
Zona Pellucida ◽  
Sperm Head ◽  
Reproductive Characteristics ◽  
Cumulus Oophorus ◽  
The Matrix ◽  
Main Components ◽  
Initial Binding ◽  
Structural Matrix

To obtain further perspective on reproduction and particularly gamete function among so-called primitive mammals presently grouped in the Order Insectivora, we have examined the African hedgehog, Atelerix albiventris, in light of unusual features reported in shrews and moles. Atelerix proves to share many but not all of the characteristics seen in these other insectivores. The penis of Atelerix has a 'snail-like' form, but lacks the surface spines common in insectivores and a number of other mammals. Hedgehog spermatozoa display an eccentric insertion of the tail on the sperm head, and they manifest the barbs on the perforatorium that, in shrews, probably effect the initial binding of the sperm head to the zona pellucida. As a possible correlate, the structural matrix of the hedgehog acrosome comprises only two main components, as judged by immunoblotting, rather than the complex of peptides seen in the matrix of some higher mammals. The Fallopian tube of Atelerix is relatively simple; it displays only minor differences in width and in the arborized epithelium between the isthmus and ampulla, and shows no evidence of the unusual sperm crypts that characterize the isthmus or ampulla, depending on the species, in shrews and moles. In common with other insectivores, Atelerix appears to be an induced ovulator, as judged by the ovulation of some 6-8 eggs by about 23 h after injection of hCG. The dense cumulus oophorus appeared to have little matrix, in keeping with the modest dimensions of the tubal ampulla and, while it was not quite as discrete as that of soricids, it did show the same insensitivity to 0.5% (w/v) ovine or bovine hyaluronidase.

APPLICATION OF THE EARLY DAMAGE DIAGNOSTICS TECHNIQUE TO EXAMINATION OF THE AVIATION PANEL

2019 ◽  
Vol 85 (6) ◽  
pp. 53-63 ◽  
Author(s):  
I. E. Vasil’ev ◽  
Yu. G. Matvienko ◽  
A. V. Pankov ◽  
A. G. Kalinin
Keyword(s):  
Acoustic Emission ◽  
Damage Detection ◽  
High Speed ◽  
Early Stage ◽  
Video Data ◽  
High Speed Video ◽  
Damage Diagnostics ◽  
Subsurface Defect ◽  
Sensitive Coating ◽  
Early Damage

The results of using early damage diagnostics technique (developed in the Mechanical Engineering Research Institute of the Russian Academy of Sciences (IMASH RAN) for detecting the latent damage of an aviation panel made of composite material upon bench tensile tests are presented. We have assessed the capabilities of the developed technique and software regarding damage detection at the early stage of panel loading in conditions of elastic strain of the material using brittle strain-sensitive coating and simultaneous crack detection in the coating with a high-speed video camera “Video-print” and acoustic emission system “A-Line 32D.” When revealing a subsurface defect (a notch of the middle stringer) of the aviation panel, the general concept of damage detection at the early stage of loading in conditions of elastic behavior of the material was also tested in the course of the experiment, as well as the software specially developed for cluster analysis and classification of detected location pulses along with the equipment and software for simultaneous recording of video data flows and arrays of acoustic emission (AE) data. Synchronous recording of video images and AE pulses ensured precise control of the cracking process in the brittle strain-sensitive coating (tensocoating)at all stages of the experiment, whereas the use of structural-phenomenological approach kept track of the main trends in damage accumulation at different structural levels and identify the sources of their origin when classifying recorded AE data arrays. The combined use of oxide tensocoatings and high-speed video recording synchronized with the AE control system, provide the possibility of definite determination of the subsurface defect, reveal the maximum principal strains in the area of crack formation, quantify them and identify the main sources of AE signals upon monitoring the state of the aviation panel under loading P = 90 kN, which is about 12% of the critical load.

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