scholarly journals Characteristics and Possible Role of Bovine Sperm Head-to-Head Agglutination

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1865
Author(s):  
Kohei Umezu ◽  
Shouhei Kurata ◽  
Hironori Takamori ◽  
Takashi Numabe ◽  
Yuuki Hiradate ◽  
...  
Keyword(s):  
Mitochondrial Function ◽  
Mammalian Species ◽  
Biological Significance ◽  
Sperm Head ◽  
Sperm Viability ◽  
Fertilization Process ◽  
Bovine Sperm ◽  
Fertilizing Ability ◽  
The Relationship

Although sperm head-to-head agglutination has been reported in many mammalian species, the biological significance of this unique sperm–sperm interaction remains largely unknown. Here, we aimed to examine the functional characteristics of agglutinated bovine sperm to determine the possible role of sperm agglutination in the fertilization process. We initially examined temporal changes to the degree of head-to-head agglutination in culture, and found that bovine sperm agglutinated despite the lack of sperm agglutination inducers in medium. Sperm viability and motility were evaluated by SYBR14/PI and JC-1 staining, respectively, to identify the relationship between sperm agglutination and fertilizing ability. Agglutinated sperm had increased motility, viability, and intact mitochondrial function compared with unagglutinated sperm. Furthermore, we found that heparin significantly increased the percentage of unagglutinated sperm, but did not affect viability of both agglutinated and unagglutinated sperm, suggesting that sperm agglutination dictated the viability. In conclusion, agglutinated bovine sperm maintained viability and motility for a longer time than unagglutinated sperm. Thus, we propose that the head-to-head agglutination is a crucial sperm–sperm interaction to ensure the fertilizing ability of sperm.

scholarly journals Length of the Neurogenic Period—A Key Determinant for the Generation of Upper-Layer Neurons During Neocortex Development and Evolution

2021 ◽  
Vol 9 ◽  
Author(s):  
Barbara K. Stepien ◽  
Samir Vaid ◽  
Wieland B. Huttner
Keyword(s):  
Cognitive Abilities ◽  
Cortical Neurons ◽  
Mammalian Species ◽  
Critical Role ◽  
Exact Nature ◽  
Cortical Neurogenesis ◽  
Brain Functions ◽  
The Relationship ◽  
Development And Evolution

The neocortex, a six-layer neuronal brain structure that arose during the evolution of, and is unique to, mammals, is the seat of higher order brain functions responsible for human cognitive abilities. Despite its recent evolutionary origin, it shows a striking variability in size and folding complexity even among closely related mammalian species. In most mammals, cortical neurogenesis occurs prenatally, and its length correlates with the length of gestation. The evolutionary expansion of the neocortex, notably in human, is associated with an increase in the number of neurons, particularly within its upper layers. Various mechanisms have been proposed and investigated to explain the evolutionary enlargement of the human neocortex, focussing in particular on changes pertaining to neural progenitor types and their division modes, driven in part by the emergence of human-specific genes with novel functions. These led to an amplification of the progenitor pool size, which affects the rate and timing of neuron production. In addition, in early theoretical studies, another mechanism of neocortex expansion was proposed—the lengthening of the neurogenic period. A critical role of neurogenic period length in determining neocortical neuron number was subsequently supported by mathematical modeling studies. Recently, we have provided experimental evidence in rodents directly supporting the mechanism of extending neurogenesis to specifically increase the number of upper-layer cortical neurons. Moreover, our study examined the relationship between cortical neurogenesis and gestation, linking the extension of the neurogenic period to the maternal environment. As the exact nature of factors promoting neurogenic period prolongation, as well as the generalization of this mechanism for evolutionary distinct lineages, remain elusive, the directions for future studies are outlined and discussed.

Sex steroids-induced neurogenesis in adult brain: a better look at mechanisms and mediators

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hamideh Abotalebi ◽  
Babak Ebrahimi ◽  
Raziyeh Shahriyari ◽  
Reyhaneh Shafieian
Keyword(s):  
Sex Steroids ◽  
Ventricular Zone ◽  
Mammalian Species ◽  
Adult Brain ◽  
Sex Steroid ◽  
Subgranular Zone ◽  
Human Beings ◽  
The Relationship ◽  
The Brain

Abstract Adult neurogenesis is the production of new nerve cells in the adult brain. Neurogenesis is a clear example of the neuroplasticity phenomenon which can be observed in most of mammalian species, including human beings. This phenomenon occurs, at least, in two regions of the brain: the subgranular zone of the dentate gyrus in hippocampus and the ventricular zone of lateral ventricles. Numerous studies have investigated the relationship between sex steroid hormones and neurogenesis of adult brain; of which, mostly concentrated on the role of estradiol. It has been shown that estrogen plays a significant role in this process through both classic and non-classic mechanisms, including a variety of different growth factors. Therefore, the objective of this review is to investigate the role of female sex steroids with an emphasis on estradiol and also its potential implications for regulating the neurogenesis in the adult brain.

scholarly journals Presence, induction and possible role of glucose 6-phosphatase in mammalian pancreatic islets

1969 ◽  
Vol 114 (2) ◽  
pp. 387-394 ◽  
Author(s):  
I.-B. Täljedal
Keyword(s):  
Enzyme Activity ◽  
Pancreatic Islets ◽  
Metabolic Regulation ◽  
Mammalian Species ◽  
Hydrolytic Activity ◽  
Simultaneous Action ◽  
Mouse Pancreatic Islets ◽  
Microsome Fraction ◽  
The Relationship

1. Pancreatic islets from several mammalian species were investigated for hydrolytic activity towards glucose 6-phosphate. Both the total phosphatase activity towards this substrate and the proportion cleaving glucose 6-phosphate in preference to β-glycerophosphate varied widely between species. In pancreatic-islet homogenates prepared from mice and guinea pigs there was a higher rate of liberation of Pi at pH6·7 from glucose 6-phosphate than from β-glycerophosphate. In these two species cortisone treatment enhanced the enzyme activity towards glucose 6-phosphate but not that towards β-glycerophosphate. Simultaneous injections of ethionine or puromycin blocked this stimulating effect of cortisone. 2. With whole homogenates of mouse pancreatic islets, inverse plots of the relationship between glucose 6-phosphate concentration and enzyme activity suggested the simultaneous action of two enzymes with different Km values. After fractionation of islets from obese–hyperglycaemic mice by differential centrifugation, one of these enzymes could be shown to be localized in the microsome fraction. It had Km for glucose 6-phosphate about 0·5mm and optimum pH6·7. It split glucose 6-phosphate in preference to β-glycerophosphate, glucose 1-phosphate, fructose 6-phosphate and fructose 1,6-diphosphate. Incubation of the microsomes at pH5·0 and 37° for 15min. decreased the enzyme activity by about 80%. Glucose was a potent inhibitor, the type of inhibition being neither strictly competitive nor non-competitive. It is suggested that the results indicate the presence of glucose 6-phosphatase in mammalian endocrine pancreas, and that this enzyme may play a role in the metabolic regulation of release of insulin.

scholarly journals Sperm-borne miR-202 targets SEPT7 and regulates first cleavage of bovine embryos via cytoskeletal remodeling

Development ◽  
2021 ◽  
pp. dev.189670
Author(s):  
Mengyun Wang ◽  
Yue Du ◽  
Song Gao ◽  
Zheng Wang ◽  
Pengxiang Qu ◽  
...  
Keyword(s):  
Nuclear Transfer ◽  
Target Gene ◽  
Preimplantation Embryos ◽  
Bovine Embryos ◽  
Cytoskeletal Remodeling ◽  
Cleavage Process ◽  
Bovine Sperm ◽  
The Relationship ◽  
Expression Libraries

In mammals, sperm-borne regulators can be transferred to oocytes during fertilization and have different effects on the formation of pronuclei, the first cleavage of zygotes, the development of preimplantation embryos and even the metabolism of individuals after birth. The regulatory role of sperm microRNAs (miRNAs) in the development of bovine preimplantation embryos has not been reported in detail. By constructing and screening miRNA expression libraries, we found that miR-202 was highly enriched in bovine sperm. As a target gene of miR-202, co-injection of SEPT7 siRNA can partially reverse the accelerated first cleavage of bovine embryos caused by miR-202 inhibitor. In addition, both a miR-202 mimic and SEPT7 siRNA delayed the first cleavage of somatic cell nuclear transfer (SCNT) embryos, suggesting that miR-202-SEPT7 mediates the delay of first cleavage of bovine embryos. By further exploring the relationship between miR-202 /SEPT7, HDAC6 and acetylated α-tubulin during embryonic development, we investigated how sperm-borne miR-202 regulated the first cleavage process of bovine embryos by SEPT7 and demonstrated the potential of sperm-borne miRNAs to improve the efficiency of SCNT.

Localization of the Rho GTPases and some Rho effector proteins in the sperm of several mammalian species

Zygote ◽  
2006 ◽  
Vol 14 (3) ◽  
pp. 249-257 ◽  
Author(s):  
Carl C. Ducummon ◽  
Trish Berger
Keyword(s):  
Rho Gtpases ◽  
Acrosome Reaction ◽  
Rho Gtpase ◽  
Mammalian Species ◽  
Effector Proteins ◽  
Mammalian Evolution ◽  
Bovine Sperm ◽  
Acrosomal Exocytosis ◽  
Rho Family

SummaryThe acrosome reaction is a fundamental event in the biology of the sperm and is a prerequisite to fertilization of the egg. Members of the Rho family of GTPases and their effectors are present in the cytoplasm and/or plasma membrane overlying the acrosome of porcine sperm. We have implicated the Rho family of GTPases and the Rho-activated kinase, ROCK-1, in mediating the zona-pellucida-induced acrosome reaction. Others have implicated the Rho GTPase in regulating the ionophore-induced acrosome reaction in the sperm of several mammalian species as well as in motility of bovine sperm. In this study, the localization of the Rho GTPases (RhoA, RhoB, Rac1 and Cdc42) as well as the effectors RhoGDI, PI(4)P5K and ROCK-1, was determined in boar, human, rat, ram, bull and elephant sperm. The four GTPases were each present in the sperm head of all species examined. RhoGDI was expressed in the head and tail of sperm from all species except pig, where it was present only in the head. PI(4)P5K was expressed in both head and tail of sperm from all species, but expression was typically weaker in the tail. Finally, ROCK-1 was expressed in the heads and tails of all sperm except that of the boar, where it was present only in the acrosomal region. These observations taken together suggest that the expression of Rho GTPases in sperm has been conserved throughout mammalian evolution, most likely due to the role of these GTPases in regulating acrosomal exocytosis.

scholarly journals Investigation Into the Relationship Between Sperm Cysteine-Rich Secretory Protein 2 (CRISP2) and Sperm Fertilizing Ability and Fertility of Boars

2021 ◽  
Vol 8 ◽  
Author(s):  
Fenglei Gao ◽  
Ping Wang ◽  
Kai Wang ◽  
Yushan Fan ◽  
Yuming Chen ◽  
...  
Keyword(s):  
Critical Role ◽  
Secretory Proteins ◽  
High Fertility ◽  
Cleavage Rate ◽  
Protein Levels ◽  
Fertilizing Ability ◽  
The Relationship ◽  
Sperm Fertilizing Ability

The proteins in the seminal plasma and on the sperm surface play important roles in sperm function and numerous reproductive processes. The cysteine-rich secretory proteins (CRISPs) are enriched biasedly in the male reproductive tract of mammals, and CRISP2 is the sole member of CRISPs produced during spermatogenesis; whereas the role of CRISP2 in fertilization and its association with fertility of boars are still unclear. This study aimed to investigate the relationship between the sperm CRISP2 and boar fertility, and explore its impact sperm fertilizing ability. The levels of CRISP2 protein in sperm were quantified by ELISA; correlation analysis was performed to evaluate the association between CRISP2 protein levels and boar reproductive parameters. Meanwhile, the expression of CRISP2 in boar reproductive organs and sperm, and the effects of CRISP2 on in vitro fertilization (IVF) were examined. The results showed that boars with high sperm levels of CRISP2 had high fertility. The protein levels of CRISP2 in sperm were positively correlated with the litter size (r = 0.412, p = 0.026), the number of live-born piglets (r = 0.421, p = 0.023) and the qualified piglets per litter (r = 0.381, p = 0.042). CRISP2 is specifically expressed in the testis and sperm of adult boars, and its location on sperm changed mainly from the post-acrosomal region to the apical segment of acrosome during capacitation. The cleavage rate was significantly decreased by adding the anti-CRISP2 antibody to the IVF medium, which indicates CRISP2 plays a critical role in fertilization. In conclusion, CRISP2 protein is specifically expressed in the adult testis and sperm and is associated with sperm fertilizing ability and boar fertility. Further mechanistic studies are warranted, in order to fully decipher the role of CRISP2 in the boar reproduction.

Aquaporin 11 is related to cryotolerance and fertilising ability of frozen–thawed bull spermatozoa

2018 ◽  
Vol 30 (8) ◽  
pp. 1099 ◽  
Author(s):  
Roser Morató ◽  
Noelia Prieto-Martínez ◽  
Rodrigo Muiño ◽  
Carlos O. Hidalgo ◽  
Joan E. Rodríguez-Gil ◽  
...  
Keyword(s):  
Sperm Head ◽  
Return Rates ◽  
Channel Proteins ◽  
Actual Role ◽  
Before And After ◽  
Bovine Fertility ◽  
Specific Band ◽  
The Relationship

Aquaporins (AQPs) are channel proteins involved in the transport of water and solutes across biological membranes. In the present study we identified and localised aquaporin 11 (AQP11) in bull spermatozoa and investigated the relationship between the relative AQP11 content, sperm cryotolerance and the fertilising ability of frozen–thawed semen. Bull ejaculates were classified into two groups of good and poor freezability and assessed through immunofluorescence and immunoblotting analyses before and after cryopreservation. AQP11 was localised throughout the entire tail and along the sperm head. These findings were confirmed through immunoblotting, which showed a specific band of approximately 50 kDa corresponding to AQP11. The relative amount of AQP11 was significantly (P < 0.05) higher in both fresh and frozen–thawed spermatozoa from bull ejaculates with good freezability compared with those with poorer freezability. In addition, in vitro oocyte penetration rates and non-return rates 56 days after AI were correlated with the relative AQP11 content in fresh spermatozoa. In conclusion, AQP11 is present in the head and tail of bull spermatozoa and its relative amount in fresh and frozen–thawed spermatozoa is related to the resilience of the spermatozoa to withstand cryopreservation and the fertilising ability of frozen–thawed spermatozoa. Further research is needed to elucidate the actual role of sperm AQP11 in bovine fertility.

scholarly journals Downregulation of Mitofusin 2 in Placenta Is Related to Preeclampsia

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Jun Yu ◽  
Xijiao Guo ◽  
Ruibao Chen ◽  
Ling Feng
Keyword(s):  
Mitochondrial Function ◽  
Cellular Proliferation ◽  
Mitochondrial Protein ◽  
Mitofusin 2 ◽  
Atp Assay ◽  
Qrt Pcr ◽  
Trophoblastic Cells ◽  
Hypoxic Conditions ◽  
The Relationship

Background. Mitofusin 2 (Mfn2) is a novel mitochondrial protein that is implicated in cellular proliferation and metabolism; however, the role of Mfn2 in preeclampsia (PE) remains unknown. This study aimed to explore the relationship between Mfn2 and PE.Method. Preeclamptic and normal pregnancies were enrolled in a comparative study. The expression of Mfn2 in placenta was detected by qRT-PCR. And the mitochondrial function was detected by ATP assay. Then TEV-1 cells were cultured in hypoxic conditions. mRNA and protein expressions of Mfn2 were detected by qRT-PCR and western blot separately. Cells’ viability was detected by MTT. And the mitochondrial function was detected by ATP and mitochondrial membrane potential (MMP) assay. We further knocked down the Mfn2 gene in TEV-1 cells and evaluated the cells’ viability.Results. Mfn2 and ATP expressions were significantly decreased in preeclamptic placentae compared to normal placentae. Mfn2 expression level and the viability of TEV-1 cells were reduced during hypoxic conditions. TEV-1 cells’ viability, ATP, and MMP levels were also significantly decreased after knockdown of the Mfn2 gene.Conclusions. These results suggest that defects in Mfn2 could cause mitochondrial dysfunction and decrease trophoblastic cells’ viability. Therefore, Mfn2 may be functionally involved in the pathogenesis of PE.

Choosing a Markov blanket

2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr
Keyword(s):  
Markov Blanket ◽  
Target Article ◽  
The Relationship

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.

Staring Down Death

Crisis ◽  
2016 ◽  
Vol 37 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Thomas E. Joiner ◽  
Melanie A. Hom ◽  
Megan L. Rogers ◽  
Carol Chu ◽  
Ian H. Stanley ◽  
...  
Keyword(s):  
Suicide Risk ◽  
Clinical Utility ◽  
Blink Rate ◽  
Specific Task ◽  
Careful Planning ◽  
Eye Blink ◽  
Eye Blinks ◽  
Potential Clinical Utility ◽  
The Relationship

Abstract. Background: Lowered eye blink rate may be a clinically useful indicator of acute, imminent, and severe suicide risk. Diminished eye blink rates are often seen among individuals engaged in heightened concentration on a specific task that requires careful planning and attention. Indeed, overcoming one’s biological instinct for survival through suicide necessitates premeditation and concentration; thus, a diminished eye blink rate may signal imminent suicidality. Aims: This article aims to spur research and clinical inquiry into the role of eye blinks as an indicator of acute suicide risk. Method: Literature relevant to the potential connection between eye blink rate and suicidality was reviewed and synthesized. Results: Anecdotal, cognitive, neurological, and conceptual support for the relationship between decreased blink rate and suicide risk is outlined. Conclusion: Given that eye blinks are a highly observable behavior, the potential clinical utility of using eye blink rate as a marker of suicide risk is immense. Research is warranted to explore the association between eye blink rate and acute suicide risk.

Sign in / Sign up

Export Citation Format

Share Document