In mammals, hyperactivation is essential for sperm fertilization with oocytes in vivo. Two types of hyperactivation "full-type and nonfull-type patterns" can be observed in the spermatozoa from boars, bulls, and mice. We have a hypothesis that the full-type hyperactivation is a physiological (in vivo) pattern and are elucidating its molecular bases. The aims of this study were to detect calmodulin in boar sperm flagella by Western blotting and indirect immunofluorescence and to investigate effects of extracellular Ca and calmodulin antagonists "W-7 and W-5 (W-5; a less potent antagonist)" on the occurrence of full-type hyperactivation in boar spermatozoa. Calmodulin was specifically detected as the 17-kDa antigen in the flagella and postacrosomal region of the heads. Full-type hyperactivation could be induced effectively in the samples incubated with 3.42 mM CaCl for 120-180 min, and it was significantly reduced in the concentration-dependent manners of W-7 and W-5. Suppressing effects of W-7 on the full-type hyperactivation were stronger than those of W-5. These observations indicate that flagellar calmodulin is involved in the occurrence of extracellular Ca -dependent full-type hyperactivation in boar spermatozoa. This is the first indication of the intracellular Ca -sensing molecule which can function in the full-type hyperactivation.
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http://dx.doi.org/10.1111/asj.13552 | DOI Listing |
Anim Sci J
November 2022
Laboratory of Reproductive Biology, Division of Animal Science, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
This study aimed to verify the effects of polyvinyl alcohol (PVA) and bovine serum albumin (BSA) on the induction of full-type hyperactivation in boar spermatozoa treated with a cyclic AMP analog (cBiMPS). Washed spermatozoa were treated with cBiMPS (100 μM) for 180 min. As shown in the assessment of sperm motility, PVA (0.
View Article and Find Full Text PDFSci Rep
April 2022
Department of Animal Sciences and Institute of Genomic Biology, University of Illinois at Urbana-Champaign, 1207 West Gregory Drive, Urbana, IL, 61801, USA.
Fertilizing sperm are retained by adhesion to specific glycans on the epithelium of the oviduct forming a reservoir before sperm are released from the reservoir so fertilization can ensue. Capacitated sperm lose affinity for the oviduct epithelium but the components of capacitation that are important for sperm release are uncertain. One important correlate of capacitation is the development of hyperactivated motility.
View Article and Find Full Text PDFAnim Sci J
September 2021
Laboratory of Reproductive Biology, Division of Animal Science, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
In mammals, hyperactivation is essential for sperm fertilization with oocytes in vivo. Two types of hyperactivation "full-type and nonfull-type patterns" can be observed in the spermatozoa from boars, bulls, and mice. We have a hypothesis that the full-type hyperactivation is a physiological (in vivo) pattern and are elucidating its molecular bases.
View Article and Find Full Text PDFTheriogenology
September 2020
Laboratory of Reproductive Biology, Division of Animal Science, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo, Japan. Electronic address:
Previous researches of our laboratory reported that addition of cAMP analog cBiMPS and protein phosphatase inhibitor calyculin A (stimulators of cAMP signaling cascades) improved the capacity of incubation medium to induce full-type hyperactivation in bovine ejaculated spermatozoa. However, this modified medium was valid only for samples with relatively good survivability for incubation with stimulators of cAMP signaling cascades. Thus, it is necessary to make further modified medium for evaluation of potentials to exhibit full-type hyperactivation in bovine sperm samples with relatively lower survivability.
View Article and Find Full Text PDFTheriogenology
April 2019
Laboratory of Reproductive Biology, Division of Animal Science, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Japan. Electronic address:
In bull spermatozoa, extracellular Ca-dependent full-type hyperactivation, which is characterized by the asymmetrical beating in whole parts of the middle/principal pieces, is suppressed by calyculin A-sensitive protein phosphatases. The aim of this study was to identify isoforms of these protein phosphatases. Ejaculated spermatozoa were used for the investigation on effects of protein phosphatase inhibitors (calyculin A with high specificity for both of protein phosphatases 1 and 2A, and okadaic acid with relatively higher specificity for protein phosphatase 2A than protein phosphatase 1) on the induction of extracellular Ca-dependent full-type hyperactivation by incubation with CaCl and cAMP analog (cBiMPS).
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