scholarly journals The Dynamic of the Apical Ectoplasmic Specialization between Spermatids and Sertoli Cells: The Case of the Small GTPase Rap1

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Giovanna Berruti ◽  
Chiara Paiardi
Keyword(s):  
Sertoli Cells ◽  
Human Population ◽  
Assisted Reproductive Technologies ◽  
Reproductive Technologies ◽  
Small Gtpase ◽  
Therapeutic Approaches ◽  
Tubule Lumen ◽  
Male Patients ◽  
Ectoplasmic Specialization

Despite advances in assisted reproductive technologies, infertility remains a consistent health problem worldwide. Spermiation is the process through which mature spermatids detach from the supporting Sertoli cells and are released into the tubule lumen. Spermiation failure leads to lack of mature spermatozoa and, if not occasional, could result into azoospermia, major cause of male infertility in human population. Spermatids are led through their differentiation into spermatozoa by the apical ectoplasmic specialization (aES), a testis-specific, actin-based anchoring junction restricted to the Sertoli-spermatid interface. The aES helps spermatid movement across the seminiferous epithelium, promotes spermatid positioning, and prevents the release of immature spermatozoa. To accomplish its functions, aES needs to undergo tightly and timely regulated restructuring. Even if components of aES are partly known, the mechanism/s through which aES is regulated remains still elusive. In this review, we propose a model by which the small GTPase Rap1 could regulate aES assembly/remodelling. The characterization of key players in the dynamic of aES, such as Rap1, could open new possibility to develop prognostic, diagnostic, and therapeutic approaches for male patients under treatment for infertility as well as it could lead to the identification of new target for male contraception.

Assisted Reproductive Technologies for Decision Support in Reproductive Management of Dairy Cattle in Ke

2021 ◽  
Vol 7 (1) ◽  
pp. 10-18
Author(s):  
Wilkister Nakami ◽  
◽  
Victor Tsuma ◽  
Keyword(s):  
Decision Support ◽  
Dairy Cattle ◽  
Human Population ◽  
Management Practices ◽  
Assisted Reproductive Technologies ◽  
Reproductive Technologies ◽  
Breeding Method ◽  
Reproductive Management ◽  
Low Levels ◽  
Livestock Products

The human population is expected to double in Africa by 2030 and with it a consequent rise in demand for livestock products. Reproductive technologies improve livestock productivity however, uptake of the technologies has been low in Africa, yet this is where there is a dire need for livestock products as the human population surges. This study aimed to assess knowledge extent and understanding the use of assisted reproductive technologies in decision support for reproductive management of dairy cattle in Kenya. Dairy farmers and veterinary practitioners were interviewed using a questionnaire to obtain relevant data on knowledge, attitude and practices in the use of assisted reproductive technologies in reproductive management in dairy farms. Observable heat signs was the only method used by participants to ascertain estrus in a cow. Artificial insemination technique was adopted by all farmers as the breeding method of choice. The analysis highlighted that the respondents with low levels of formal education had less knowledge on reproductive technologies and displayed risky practices. Overall, a larger proportion of respondents indicated that the assisted reproductive technologies would be important in reproductive management. The relatively low levels of awareness, higher levels of education and a willingness to use the assisted reproductive technologies in reproductive management of dairy cattle strengthen the logic of improving productivity through the application of these assisted reproductive technologies as well as improve levels of awareness of reproductive management practices. Keywords: attitude, heat detection, knowledge, pregnancy diagnosis, practices, progesterone

scholarly journals 99 Temporal and spatial characterization of interleukin-6 protein in the caprine testis

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 83-83
Author(s):  
Khalda Fadlalla
Keyword(s):  
Sertoli Cells ◽  
Interleukin 6 ◽  
Assisted Reproductive Technologies ◽  
The United States ◽  
Reproductive Technologies ◽  
Testicular Development ◽  
Cell Growth And Differentiation ◽  
And Function ◽  
Reproductive Processes

Abstract The demand for goat products is one of fastest growing segments of livestock production in the United States. Nonetheless, the development of efficient goat breeding stock remains in its infancy. Assisted reproductive technologies (ART) have the potential to enhance reproductive efficiency in goats to rapidly propagate superior genetics. In order to improve success with ART, it is pertinent to understand the factors that contribute to reproductive processes, such as spermatogenesis, as well as the factors that affect the production of viable sperm. Interleukin-6 (IL-6) is a multifunctional cytokine produced mainly by macrophages in response to foreign antigens, pathogens. In recent years, studies showed that mammalian testes produce IL-6. Under in vitro conditions, Sertoli cells secrete IL-6 following stimulation with low levels of testosterone and follicle stimulating hormone in mice. The binding of IL-6 promotes the transcription of genes important to cellular processes, such as cell growth and differentiation, which are critical to testicular function. The overall objective of this study was to characterize IL-6 protein in goat testes during three life stages: neonate (n = 3; 13- 21days), pre-pubertal (n = 3; 110–121 days) and adult (n = 3; 11–12 month) goats. Preliminary data from western blotting revealed that testicular goat tissues express IL-6. Immunohistochemical staining of IL-6 in the peritubular myoid cells and interstitial cells of neonate, pre-pubertal and adult goats; further Sertoli cells express IL-6 in adult goats. Our findings suggest that IL-6 may play a key role in testicular development and function; however, further research is needed.

scholarly journals Assisted Reproductive Technologies in Brazil: characterization of centers and profiles from patients treated

2020 ◽  
Author(s):  
Rosana Machin ◽  
Douglas Mendosa ◽  
Maria Helena Oliva Augusto ◽  
Pedro Augusto Araújo Monteleone
Keyword(s):  
Assisted Reproductive Technologies ◽  
Reproductive Technologies

scholarly journals Molecular characterization of a congenital overgrowth syndrome induced by assisted reproduction

2017 ◽  
Author(s):  
◽  
Zhiyuan Chen
Keyword(s):  
Molecular Mechanisms ◽  
Assisted Reproductive Technologies ◽  
Epigenetic Modification ◽  
Reproductive Technologies ◽  
Imprinted Genes ◽  
Aberrant Expression ◽  
Regulate Gene Expression ◽  
Loss Of Imprinting ◽  
Regulate Gene

Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth condition with increased likelihood to develop childhood tumors. Children conceived with the use of assisted reproductive technologies (ART) have an increased frequency to have BWS compared to naturally conceived individuals. In ruminants, the use of ART can induce a similar overgrowth condition that phenotypically recapitulates BWS, which is referred to as large offspring syndrome (LOS). It is believed that these two overgrowth conditions are the result of misregulation of a set of genes that are expressed only from the maternally- or paternally-inherited chromosomes. These genes are known as imprinted genes. In this dissertation, we demonstrate that multiple imprinted genes are misregulated in LOS, as in a subset of BWS. Further, we show that global misregulation of non-imprinted genes in addition to loss-of-imprinting characterizes LOS. Importantly, most of the genes with aberrant expression are not associated with differential DNA methylation, an epigenetic modification that can regulate gene expression. Our results lay the foundation to predict the occurrence of LOS and help understand the molecular mechanisms of these congenital overgrowth conditions.

scholarly journals New insights into the role of centrosomes in mammalian fertilization and implications for ART

Reproduction ◽  
2011 ◽  
Vol 142 (6) ◽  
pp. 793-801 ◽  
Author(s):  
Heide Schatten ◽  
Qing-Yuan Sun
Keyword(s):  
Molecular Mechanisms ◽  
Assisted Reproductive Technologies ◽  
Mammalian Species ◽  
Reproductive Technologies ◽  
Therapeutic Approaches ◽  
Mitotic Apparatus ◽  
Proper Diagnosis ◽  
Mammalian Fertilization ◽  
Molecular Aspects

In non-rodent mammalian species, including humans, the oocyte and sperm both contribute centrosomal components that are most important for successful fertilization. Centrosome pathologies in sperm and the oocyte can be causes for infertility which may be overcome by assisted reproductive technologies based on proper diagnosis of specific centrosomal pathologies. However, we do not yet fully understand the cell and molecular mechanisms underlying centrosome functions in germ cells and in the developing embryo, which calls for directed specific investigations to identify centrosome-related pathologies that include components in sperm, egg, or centrosome regulation within the fertilized oocyte. The present review highlights cellular and molecular aspects of centrosomes and centrosome–nuclear interactions focused on nuclear mitotic apparatus protein during fertilization and proposes future directions in expanding therapeutic approaches related to centrosome pathologies that may play a role in still unexplained causes of infertility.

Aberrant DNA Methylation of IGF2-H19 Locus in Human Fetus and in Spermatozoa From Assisted Reproductive Technologies

2018 ◽  
Vol 26 (7) ◽  
pp. 997-1004 ◽  
Author(s):  
Hangying Lou ◽  
Fang Le ◽  
Minhao Hu ◽  
Xinyun Yang ◽  
Lejun Li ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Assisted Reproductive Technologies ◽  
Quantitative Polymerase Chain Reaction ◽  
Methylation Status ◽  
Reproductive Technologies ◽  
Semen Parameters ◽  
Control Group ◽  
Expression Levels ◽  
Small Nuclear Ribonucleoprotein ◽  
Male Patients

Given the higher risk of developing imprinting disorders in assisted reproductive technology (ART)-conceived children, we hypothesized that ART may affect DNA methylation of the insulin-like growth factor 2 (IGF2), H19, small nuclear ribonucleoprotein polypeptide N (SNRPN) differentially methylated regions (DMRs) at the fetal stage, which in turn may be associated with sperm abnormalities. A total of 4 patient groups were recruited, namely, multifetal reduction following in vitro fertilization (IVF)/ intracytoplasmic sperm injection (ICSI; n = 56), multifetal reduction following controlled ovarian hyperstimulation (COH; n = 42), male patients with normal semen parameters denoted as normozoospermia group (NZ) for IVF (n = 36), and male patients presenting with asthenozoospermia (OAZ) for ICSI (n = 38). The expression levels and the DNA methylation status of IGF2- H19 and SNRPN DMRs in the fetuses and the semen samples were evaluated by real-time quantitative polymerase chain reaction and pyrosequencing. In our results, the expression levels of H19 were significantly higher, whereas the methylation rates were lower in IVF-conceived fetuses compared to the control group ( P < .05). Furthermore, higher methylation rates of IGF2 DMR2 and SNRPN DMR were detected both in IVF- and ICSI-conceived fetuses ( P < .05). The data further indicated that the patients who presented with the majority of the CpG sites in the H19 DMR region that were lower methylated were those in the OAZ group. The results demonstrated that the epigenetic dysregulations of IGF2-H19 and SNRPN DMRs that were caused by ART were noted in the fetuses. Moreover, the present study suggested that epigenetic perturbations of the H19 DMR might be a key biomarker for spermatogenesis defects in humans.

scholarly journals Calcium influx in mammalian eggs

Reproduction ◽  
2013 ◽  
Vol 145 (4) ◽  
pp. R97-R105 ◽  
Author(s):  
Chunmin Wang ◽  
Zoltan Machaty
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Assisted Reproductive Technologies ◽  
Calcium Influx ◽  
Critical Role ◽  
Reproductive Technologies ◽  
Signaling Cascades ◽  
Mammalian Eggs ◽  
Stimulation Of

Calcium (Ca2+) signals are involved in the regulation of oocyte maturation and play a critical role during fertilization. In the egg, Ca2+is stored in the lumen of the endoplasmic reticulum and a signal is generated when the stored Ca2+is released through specialized channels in the membrane of the endoplasmic reticulum to elevate the free Ca2+concentration in the cytoplasm. Extracellular Ca2+is also important, indicated by the fact that the mobilization of luminal Ca2+is typically followed by Ca2+entry across the plasma membrane. The transmembrane Ca2+flux replenishes the endoplasmic reticulum, and thus, it is essential to sustain prolonged Ca2+signals. It also seems to be responsible for the stimulation of important signaling cascades required for complete egg activation. Characterization of the pathway that mediates Ca2+entry implies that its major components include STIM1, a protein that senses the filling status of the stores, and ORAI1, a channel protein located in the plasma membrane. Defining the mechanism and functions of Ca2+entry will not only lead to a better understanding of egg physiology but may also help improving the efficiency of a number of assisted reproductive technologies.

Re-imagining Reproduction: Unsettling Metaphors in the History of Imperial Science and Commercial Surrogacy in India

Somatechnics ◽  
2015 ◽  
Vol 5 (1) ◽  
pp. 88-103 ◽  
Author(s):  
Kalindi Vora
Keyword(s):  
Assisted Reproductive Technologies ◽  
Reproductive Technologies ◽  
The Body ◽  
Body Parts ◽  
Colonial History ◽  
Women's Bodies ◽  
Commercial Surrogacy ◽  
Art Practices ◽  
History Of ◽  
Travel Industry

This paper provides an analysis of how cultural notions of the body and kinship conveyed through Western medical technologies and practices in Assisted Reproductive Technologies (ART) bring together India's colonial history and its economic development through outsourcing, globalisation and instrumentalised notions of the reproductive body in transnational commercial surrogacy. Essential to this industry is the concept of the disembodied uterus that has arisen in scientific and medical practice, which allows for the logic of the ‘gestational carrier’ as a functional role in ART practices, and therefore in transnational medical fertility travel to India. Highlighting the instrumentalisation of the uterus as an alienable component of a body and subject – and therefore of women's bodies in surrogacy – helps elucidate some of the material and political stakes that accompany the growth of the fertility travel industry in India, where histories of privilege and difference converge. I conclude that the metaphors we use to structure our understanding of bodies and body parts impact how we imagine appropriate roles for people and their bodies in ways that are still deeply entangled with imperial histories of science, and these histories shape the contemporary disparities found in access to medical and legal protections among participants in transnational surrogacy arrangements.

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