Identification of the sperm motility-initiating substance in the newt, Cynops pyrrhogaster, and its possible relationship with the acrosome reaction during internal fertilization

SummaryThe egg jelly of Discoglossus pictus contains sperm motility-activating activity, the molecular basis of which has not been studied. Discoglossus pictus sperm initiated motility immediately after immersion in egg-jelly extract, as well as after immersion in hyposmotic solution, which initiates sperm motility in the external fertilization of anuran amphibians. Sequential treatment of the D. pictus sperm with these two solutions revealed the predominant effect of hyposmolality in initiation of motility. The motility initiation induced by jelly extract was suppressed by a monoclonal antibody (mAb) that is specific for the 34 kDa sperm motility-initiating substance (SMIS) in the egg jelly of the newt, Cynops pyrrhogaster. Immunoblotting using the anti-SMIS mAb revealed several antigenic proteins that included major ones with sizes of 18- and 34-kDa in D. pictus jelly extract. Scanning electron microscopic observation revealed that granules of jelly matrix, in which SMIS localizes and which have a critical role in the internal fertilization of C. pyrrhogaster, were not observed near the surface of the D. pictus egg jelly. These results suggest that sperm motility-activating activity in egg jelly of D. pictus may be mediated by SMIS homologous proteins that act through a mechanism that is partially different from that of C. pyrrhogaster.

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Contribution of different Ca2+ channels to the acrosome reaction-mediated initiation of sperm motility in the newt Cynops pyrrhogaster

Zygote ◽

10.1017/s0967199413000609 ◽

2013 ◽

Vol 23 (3) ◽

pp. 342-351 ◽

Cited By ~ 6

Author(s):

Eriko Takayama-Watanabe ◽

Hiroto Ochiai ◽

Shunpei Tanino ◽

Akihiko Watanabe

Keyword(s):

Sperm Motility ◽

Acrosome Reaction ◽

Emission Spectrometry ◽

Cynops Pyrrhogaster ◽

Reliable Source ◽

Voltage Dependent ◽

Egg Jelly ◽

High Level ◽

Sequential Gating ◽

Ca2 Channels

SummaryInitiation of sperm motility in urodeles, which is induced by a sperm motility-initiating substance (SMIS) in the sequestered granules on the surface of egg jelly, is mediated by the acrosome reaction (AR), which is triggered by an AR-inducing substance (ARIS) on a sheet-like structure. Details of the unique process of the interaction between egg jelly and sperm in these species is still unclear. The current study showed the fine structure of egg jelly in the newt Cynops pyrrhogaster, a urodele species, revealing that its outer surface was covered by a sheet-like structure of approximately 0.29 μm in thickness. Granules of approximately 2 μm in diameter with small particles of approximately 54 nm were attached to its surface and distributed inhomogeneously just beneath the sheet-like structure. Emission spectrometry revealed that the Ca2+ concentration was maintained at a high level compared with that of the blood plasma and the vas deferens fluid, suggesting that egg jelly is a reliable source of Ca2+ for the sperm–egg interaction. Blockers of the T-type voltage-dependent Ca2+ channel (VDCC), but not the L-type VDCC, inhibited both AR and initiation of sperm motility. Conversely, Ni+, which affects the α1 H subunit of T-type VDCC, only inhibited the initiation of sperm motility. These data suggest that, in response to ARIS and SMIS, sequential gating of distinct Ca2+ channels occurs in the AR, followed by the initiation of sperm motility on the surface of the egg jelly in C. pyrrhogaster at fertilization.

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Molecular basis of adaptive evolution of sperm motility involved in in vivo fertilization of terrestrial animals

Impact ◽

10.21820/23987073.2020.6.73 ◽

2020 ◽

Vol 2020 (6) ◽

pp. 73-75

Author(s):

Akihiko Watanabe

Keyword(s):

Sexual Reproduction ◽

Sperm Motility ◽

Asexual Reproduction ◽

Acrosome Reaction ◽

Sperm Morphology ◽

Adaptive Potential ◽

Selective Pressures ◽

The Face ◽

Genetic Profiles

One of the unifying traits of life on this planet is reproduction, or life's ability to make copies of itself. The mode of reproduction has evolved over time, having almost certainly begun with simple asexual reproduction when the ancestral single celled organism divided into two. Since these beginnings' life has tried out numerous strategies, and perhaps one of the most important and successful has been sexual reproduction. This form of reproduction relies on the union of gametes, otherwise known as sperm and egg. Evolutionarily, sexual reproduction allows for greater adaptive potential because the genes of two unique individuals have a chance to recombine and mix in order to produce a new individual. Unlike asexual reproduction which produces genetically-identical clones of the parent individual, sex produces offspring with novel genes and combinations of genes. Therefore, in the face of new selective pressures there is a higher chance that one of these novel genetic profiles will produce an adaptation that is advantageous in the new circumstances. Dr Akihiko Watanabe is a reproductive biologist based in the Department of Biology, Faculty of Science Yamagata University in Japan, he is currently working on three research projects; a comparative study on the signalling pathways for inducing sperm motility and acrosome reaction in amphibians, the mechanism behind the adaptive modification of sperm morphology and motility, and the origin of sperm motility initiating substance (SMIS).

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PACAP-mediated sperm–cumulus cell interaction promotes fertilization

Reproduction ◽

10.1530/rep-10-0201 ◽

2011 ◽

Vol 141 (2) ◽

pp. 163-171 ◽

Cited By ~ 30

Author(s):

Ichiro Tanii ◽

Tadashi Aradate ◽

Kouhei Matsuda ◽

Akira Komiya ◽

Hideki Fuse

Keyword(s):

Sperm Motility ◽

Acrosome Reaction ◽

Cumulus Cell ◽

Cumulus Cells ◽

Cell Interaction ◽

Fertilization Rate ◽

Type I ◽

Dependent Manner ◽

Sperm Penetration

The developing acrosome in spermatids contains pituitary adenylate cyclase-activating polypeptide (PACAP). However, the role of the acrosomal PACAP remains unclear because it has not been detected in mature spermatids and sperm. We reinvestigated whether the sperm acrosome contains PACAP. An antiserum produced against PACAP reacted to the anterior acrosome in epididymal sperm fixed under mild conditions, suggesting that PACAP acts on oocytes and/or cumulus cells at the site of fertilization. Immunolabeling and RT-PCR demonstrated the presence of PACAP type I receptor, a PACAP-specific receptor, in postovulatory cumulus cells. To investigate the role of PACAP in fertilization, we pretreated cumulus–oocyte complexes with the polypeptide. At a low concentration of sperm, the fertilization rate was significantly enhanced by PACAP in a dose-dependent manner. Sperm penetration through the oocyte investment, cumulus layer, and zona pellucida was also enhanced by PACAP. The enhancement was probably due to an enhancement in sperm motility and the zona-induced acrosome reaction, which were stimulated by a cumulus cell-releasing factor. Indeed, PACAP treatment increased the secretion of progesterone from the cumulus–oocyte complexes. These results strongly suggest that in response to PACAP, cumulus cells release a soluble factor that probably stimulates sperm motility and the acrosome reaction, thereby promoting fertilization.

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Effects of calpain and Rho-kinase inhibitors on the acrosome reaction and motility of fowl spermatozoa in vitro

Reproduction ◽

10.1530/rep.1.00588 ◽

2006 ◽

Vol 131 (1) ◽

pp. 71-79 ◽

Cited By ~ 7

Author(s):

K Ashizawa ◽

G J Wishart ◽

S Katayama ◽

D Takano ◽

M Maeda ◽

...

Keyword(s):

Sperm Motility ◽

Acrosome Reaction ◽

Kinase Inhibitors ◽

Rho Kinase ◽

Specific Inhibitor ◽

Immunoblot Analysis ◽

Calpain Inhibitor ◽

Cytoplasmic Matrix ◽

Sperm Extract

At the avian body temperature of 40 °C, intact fowl spermatozoa require Ca2+for the initiation of motility and a combination of both Ca2+and homogenized inner perivitelline layer (IPVL) together to induce the acrosome reaction. Within the range of 1–100 μmol/l, neither PD 150606 (a Ca2+-dependent calpain inhibitor) nor Y-27632 (an inhibitor of Ca2+-dependent Rho-kinase) were able to inhibit the acrosome reaction induced by the presence of Ca2+and IPVL. However, PD 150606, although not Y-27632, was able to inhibit sperm motility initiated by Ca2+, as well as motility initiated by calyculin A – a specific inhibitor of protein phosphatases, which also initiates sperm motility at 40 °C. The addition of PD 150606 did not reduce the ATP concentrations of intact spermatozoa, nor the motility of demembranated spermatozoa. Immunoblot analysis of sperm extract using a polyclonal antibody against calpain 12 revealed a cross-reacting protein of approximately 80 kDa. These results suggest that Rho-kinase is not involved in the regulation of the acrosome reaction or of motility in fowl spermatozoa. In contrast, calpain appears to be involved in the regulation of flagellar movement, but not izn that of the acrosome reaction. Furthermore, it seems that endogenous calpain is present in the cytoplasmic matrix and/or the plasma membrane, but not retained in the axoneme and/or accessory cytoskeletal components.

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Sphingomyelin Synthase 2 Participate in the Regulation of Sperm Motility and Apoptosis

Molecules ◽

10.3390/molecules25184231 ◽

2020 ◽

Vol 25 (18) ◽

pp. 4231

Author(s):

Xiatian Li ◽

Tao Luo ◽

Hua Li ◽

Nianlong Yan

Keyword(s):

Signaling Pathways ◽

Sperm Motility ◽

Acrosome Reaction ◽

Caspase 3 ◽

Human Sperm ◽

Erk Signaling ◽

Sperm Function ◽

Sphingomyelin Synthase ◽

Protein Levels ◽

Penetration Ability

Sphingomylin participates in sperm function in animals, and also regulates the Akt and ERK signaling pathways, both of which are associated with the asthenospermia. Sphingomyelin synthase 2 (SMS2) is involved in the biosynthesis of sphingomylin. To determine the relationship between SMS2 and human sperm function, we analyzed the distribution of SMS2 in human sperm and testes, and SMS2 expression in patients with asthenospermia and normozoospermia; human sperm were treated with anti-SMS2, and the sperm motility, penetration ability into methylcellulose, capacitation and acrosome reaction, and sperm [Ca2+]i imaging were evaluated, while the Akt and ERK pathway and cleaved caspase 3 were also analyzed. Results showed that SMS2 was localized in the testis and human sperm, and the protein levels of normozoospermia were higher than asthenospermia. Inhibition of SMS2 activity significantly decreased sperm motility and penetration ability into methylcellulose, but had no influence on capacitation and acrosome reaction, or on intracellular [Ca2+]i compared to IgG-treated control groups. Moreover, the phosphorylation level of Akt was decreased, whereas the phosphorylation of ERK and cleaved-caspase 3 levels were significantly increased. Taken together, SMS2 can affect sperm motility and penetration ability into methylcellulose, and participate in apoptosis associated with the Akt and ERK signaling pathways.

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