The E-modulus of the oocyte is a non-destructive measure of zona pellucida hardening

After fertilization, the oocyte-specific metalloproteinase ovastacin is released and cleaves the zona pellucida protein 2 (ZP2), making the zona pellucida impermeable to sperm. Before fertilization, the zona remains permeable because previously released ovastacin is inhibited by fetuin-B. Consequently, in the absence of fetuin-B, ZP2 cleavage occurs prematurely and leads to infertility of female fetuin-B deficient mice. In contrast, fetuin-B/ovastacin double-deficient oocytes show a permanently permeable zona with intact ZP2. In this study, we asked if the elastic modulus of the zona pellucida informs about ZP2 cleavage and thus could serve as a new reference of oocyte fertility. Therefore, we determined the elastic modulus of mouse oocytes by nanoindentation as a direct measure of mechanical zona hardening. The elastic modulus reflects ZP2 cleavage, but with more than double sensitivity compared to immunoblot analysis. The elastic modulus measurement allowed to define the range of zona hardening, confined by the extreme states of the zona pellucida in fetuin-B and ovastacin-deficient oocytes with cleaved and uncleaved ZP2, respectively. We present here nanoindentation as a method to quantify the effect of potential contributing factors on the zona hardening of individual oocytes. To demonstrate this, we showed that mechanical hardening of the zona pellucida is forced by recombinant ovastacin, inhibited by additional administration of fetuin-B, and unaffected by zinc. Since the change in elastic modulus is induced by ZP2 cleavage, an automated elastic modulus measurement of oocytes may serve as a novel sensitive, non-destructive, marker-free, and observer-unbiased method for assessing individual oocyte quality.

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Pig zona pellucida 2 (pZP2) protein does not participate in zona pellucida formation in transgenic mice

Reproduction ◽

10.1530/rep.1.01016 ◽

2006 ◽

Vol 132 (3) ◽

pp. 455-464 ◽

Cited By ~ 4

Author(s):

Akiko Hasegawa ◽

Nozomi Kanazawa ◽

Hideaki Sawai ◽

Shinji Komori ◽

Koji Koyama

Keyword(s):

Extracellular Matrix ◽

Transgenic Mice ◽

Molecular Species ◽

Zona Pellucida ◽

Transgenic Protein ◽

Specific Manner ◽

Species Specific ◽

Deficient Mice

The zona pellucida, an extracellular matrix surrounding mammalian oocytes, is composed of three or four glycoproteins. It is well known that the zona pellucida plays several critical roles during fertilization, but there is little knowledge about its formation. The purpose of this study is to examine whether a pig zona pellucida glycoprotein 2 (pZP2) would assemble with mouse zona pellucida. A transgene construct was prepared by placing a minigene encoding pZP2 downstream from the promoter of mouse ZP2. The result showed that the transgenic protein was synthesized in growing oocytes but not incorporated into the zona pellucida. Furthermore, the pZP2 transgene did not rescue the phenotype in ZP2-knockout zona-deficient mice. These results indicate that pZP2 does not participate in mouse zona pellucida formation and the zona pellucida is constituted from its component proteins in a molecular species-specific manner between mice and pigs.

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The Effects of Creep on Elastic Modulus Measurement Using Nanoindentation

MRS Proceedings ◽

10.1557/proc-649-q7.1 ◽

2000 ◽

Vol 649 ◽

Cited By ~ 2

Author(s):

G. Feng ◽

A.H.W. Ngan

Keyword(s):

Elastic Modulus ◽

Elastic Deformation ◽

Elastic Moduli ◽

Holding Time ◽

Time Dependent ◽

Nanoindentation Test ◽

Modification Method ◽

Unloading Rate ◽

Modulus Measurement

ABSTRACTDuring the unloading segment of nanoindentation, time dependent displacement (TDD) accompanies elastic deformation. Consequently the modulus calculated by the Oliver-Pharr scheme can be overestimated. In this paper we present evidences for the influence of the measured modulus by TDD. A modification method is also presented to correct for the effects of TDD by extrapolating the TDD law in the holding process to the beginning of the unloading process. Using this method, the appropriate holding time and unloading rate can be estimated for nanoindentation test to minimise the effects of TDD. The elastic moduli of three materials computed by the modification method are compared with the results without considering the TDD effects.

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A harmless thin film elastic modulus measurement method through bending the nonlinear sliding cantilever beam

Measurement ◽

10.1016/j.measurement.2021.108984 ◽

2021 ◽

Vol 175 ◽

pp. 108984

Author(s):

Jianhua Tang ◽

Lezhang Liu ◽

Li Jiang ◽

Hui Huang ◽

Qiongyao Wang

Keyword(s):

Thin Film ◽

Elastic Modulus ◽

Cantilever Beam ◽

Measurement Method ◽

Modulus Measurement

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Calcium-free vitrification reduces cryoprotectant-induced zona pellucida hardening and increases fertilization rates in mouse oocytes

Reproduction ◽

10.1530/rep.1.00878 ◽

2006 ◽

Vol 131 (1) ◽

pp. 53-61 ◽

Cited By ~ 126

Author(s):

Mark G Larman ◽

Courtney B Sheehan ◽

David K Gardner

Keyword(s):

Ethylene Glycol ◽

Zona Pellucida ◽

Cell Number ◽

Blastocyst Stage ◽

Initial Increase ◽

Cell Stage ◽

Free Treatment ◽

Zona Hardening ◽

Free Media ◽

Oocyte Freezing

Despite the success of embryo cyropreservation, routine oocyte freezing has proved elusive with only around 200 children born since the first reported birth in 1986. The reason for the poor efficiency is unclear, but evidence of zona pellucida hardening following oocyte freezing indicates that current protocols affect oocyte physiology. Here we report that two cryoprotectants commonly used in vitrification procedures, dimethyl sulfoxide (DMSO) and ethylene glycol, cause a large transient increase in intracellular calcium concentration in mouse metaphase II (MII) oocytes comparable to the initial increase triggered at fertilization. Removal of extracellular calcium from the medium failed to affect the response exacted by DMSO challenge, but significantly reduced the ethylene glycol-induced calcium increase. These results suggest that the source of the DMSO-induced calcium increase is solely from the internal calcium pool, as opposed to ethylene glycol that causes an influx of calcium across the plasma membrane from the external medium. By carrying out vitrification in calcium-free media, it was found that zona hardening is significantly reduced and subsequent fertilization and development to the two-cell stage significantly increased. Furthermore, such calcium-free treatment appears not to affect the embryo adversely, as shown by development rates to the blastocyst stage and cell number/allocation. Since zona hardening is one of the early activation events normally triggered by the sperm-induced calcium increases observed at fertilization, it is possible that other processes are negatively affected by the calcium rise caused by cryoprotectants used during oocyte freezing, which might explain the current poor efficiency of this technique.

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Elastic Modulus Measurement

Reference Module in Materials Science and Materials Engineering ◽

10.1016/b978-0-12-803581-8.03417-2 ◽

2016 ◽

Author(s):

W. Hermann ◽

H.-G. Sockel ◽

K.L. Edwards

Keyword(s):

Elastic Modulus ◽

Modulus Measurement

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Elastic modulus measurement of ultrathin layer using gas cluster ion beam

Journal of Advanced Mechanical Design Systems and Manufacturing ◽

10.1299/jamdsm.2021jamdsm0076 ◽

2021 ◽

Vol 15 (6) ◽

pp. JAMDSM0076-JAMDSM0076

Author(s):

Hiroshi TANI ◽

Renguo LU ◽

Shinji KOGANEZAWA ◽

Norio TAGAWA

Keyword(s):

Elastic Modulus ◽

Ion Beam ◽

Cluster Ion ◽

Modulus Measurement ◽

Gas Cluster Ion Beam ◽

Ultrathin Layer

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Elastic modulus measurement of thermoplastic composites through modal analysis

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1189/1/012020 ◽

2021 ◽

Vol 1189 (1) ◽

pp. 012020

Author(s):

B Harshavardhan ◽

R Ravishankar ◽

B Suresha ◽

U Arun C Dixit

Keyword(s):

Elastic Modulus ◽

Modal Analysis ◽

Thermoplastic Composites ◽

Modulus Measurement

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A simple, high-resolution, non-destructive method for determining the spatial gradient of the elastic modulus of insect cuticle

Journal of The Royal Society Interface ◽

10.1098/rsif.2018.0312 ◽

2018 ◽

Vol 15 (145) ◽

pp. 20180312 ◽

Cited By ~ 8

Author(s):

S h. Eshghi ◽

M. Jafarpour ◽

A. Darvizeh ◽

S. N. Gorb ◽

H. Rajabi

Keyword(s):

Elastic Modulus ◽

High Resolution ◽

Three Dimensional ◽

Insect Cuticle ◽

Spatial Gradient ◽

Engineering Systems ◽

Small Complex ◽

Load Carrying ◽

Using Data ◽

Non Destructive

Nature has evolved structures with high load-carrying capacity and long-term durability. The principles underlying the functionality of such structures, if studied systematically, can inspire the design of more efficient engineering systems. An important step in this process is to characterize the material properties of the structure under investigation. However, direct mechanical measurements on small complex-shaped biological samples involve numerous technical challenges. To overcome these challenges, we developed a method for estimation of the elastic modulus of insect cuticle, the second most abundant biological composite in nature, through simple light microscopy. In brief, we established a quantitative link between the autofluorescence of different constituent materials of insect cuticle, and the resulting mechanical properties. This approach was verified using data on cuticular structures of three different insect species. The method presented in this study allows three-dimensional visualisation of the elastic modulus, which is impossible with any other available technique. This is especially important for precise finite-element modelling of cuticle, which is known to have spatially graded properties. Considering the simplicity, ease of implementation and high-resolution of the results, our method is a crucial step towards a better understanding of material–function relationships in insect cuticle, and can potentially be adapted for other graded biological materials.

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