scholarly journals New Insights into the Mammalian Egg Zona Pellucida

2021 ◽  
Vol 22 (6) ◽  
pp. 3276
Author(s):  
Carla Moros-Nicolás ◽  
Pascale Chevret ◽  
María Jiménez-Movilla ◽  
Blanca Algarra ◽  
Paula Cots-Rodríguez ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Mammalian Species ◽  
Protein Composition ◽  
Dynamic Structure ◽  
Cumulus Cells ◽  
Point Of View ◽  
Before And After ◽  
Duplication Events ◽  
The Many ◽  
Species Specific

Mammalian oocytes are surrounded by an extracellular coat called the zona pellucida (ZP), which, from an evolutionary point of view, is the most ancient of the coats that envelope vertebrate oocytes and conceptuses. This matrix separates the oocyte from cumulus cells and is responsible for species-specific recognition between gametes, preventing polyspermy and protecting the preimplantation embryo. The ZP is a dynamic structure that shows different properties before and after fertilization. Until very recently, mammalian ZP was believed to be composed of only three glycoproteins, ZP1, ZP2 and ZP3, as first described in mouse. However, studies have revealed that this composition is not necessarily applicable to other mammals. Such differences can be explained by an analysis of the molecular evolution of the ZP gene family, during which ZP genes have suffered pseudogenization and duplication events that have resulted in differing models of ZP protein composition. The many discoveries made in recent years related to ZP composition and evolution suggest that a compilation would be useful. Moreover, this review analyses ZP biosynthesis, the role of each ZP protein in different mammalian species and how these proteins may interact among themselves and with other proteins present in the oviductal lumen.

scholarly journals Update on mammalian sperm capacitation: how much does the horse differ from other species?

Reproduction ◽  
2019 ◽  
Vol 157 (5) ◽  
pp. R181-R197 ◽  
Author(s):  
Bart Leemans ◽  
Tom A E Stout ◽  
Catharina De Schauwer ◽  
Sonia Heras ◽  
Hilde Nelis ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Zona Pellucida ◽  
Mammalian Species ◽  
Cumulus Cells ◽  
Sperm Cells ◽  
Cholesterol Depletion ◽  
Sperm Capacitation ◽  
Sperm Plasma Membrane ◽  
Species Specific

In contrast to various other mammalian species, conventional in vitro fertilization (IVF) with horse gametes is not reliably successful. In particular, stallion spermatozoa fails to penetrate the zona pellucida, most likely due to incomplete activation of stallion spermatozoa (capacitation) under in vitro conditions. In other mammalian species, specific capacitation triggers have been described; unfortunately, none of these is able to induce full capacitation in stallion spermatozoa. Nevertheless, knowledge of capacitation pathways and their molecular triggers might improve our understanding of capacitation-related events observed in stallion sperm. When sperm cells are exposed to appropriate capacitation triggers, several molecular and biochemical changes should be induced in the sperm plasma membrane and cytoplasm. At the level of the sperm plasma membrane, (1) an increase in membrane fluidity, (2) cholesterol depletion and (3) lipid raft aggregation should occur consecutively; the cytoplasmic changes consist of protein tyrosine phosphorylation and elevated pH, cAMP and Ca2+ concentrations. These capacitation-related events enable the switch from progressive to hyperactivated motility of the sperm cells, and the induction of the acrosome reaction. These final capacitation triggers are indispensable for sperm cells to migrate through the viscous oviductal environment, penetrate the cumulus cells and zona pellucida and, finally, fuse with the oolemma. This review will focus on molecular aspects of sperm capacitation and known triggers in various mammalian species. Similarities and differences with the horse will be highlighted to improve our understanding of equine sperm capacitation/fertilizing events.

scholarly journals Mammalian spermatozoa and cumulus cells bind to a 3D model generated by recombinant zona pellucida protein-coated beads

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Julieta Gabriela Hamze ◽  
Analuce Canha-Gouveia ◽  
Blanca Algarra ◽  
María José Gómez-Torres ◽  
María Concepción Olivares ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Molecular Mechanisms ◽  
3D Model ◽  
Mammalian Species ◽  
Three Dimensional ◽  
Cumulus Cells ◽  
Mammalian Sperm ◽  
Gamete Recognition ◽  
Specific Proteins ◽  
C And N

AbstractThe egg is a spherical cell encapsulated by the zona pellucida (ZP) which forms a filamentous matrix composed of several glycoproteins that mediate gamete recognition at fertilization. Studies on molecular mechanisms of sperm-egg binding are limited in many mammalian species by the scarcity of eggs, by ethical concerns in harvesting eggs, and by the high cost of producing genetically modified animals. To address these limitations, we have reproduced a three-dimensional (3D) model mimicking the oocyte’s shape, by means of magnetic sepharose beads coated with recombinant ZP glycoproteins (BZP) and cumulus cells. Three preparations composed of either ZP2 (C and N-termini; BZP2), ZP3 (BZP3) or ZP4 (BZP4) were obtained and characterized by protein SDS-PAGE, immunoblot and imaging with confocal and electron microscopy. The functionality of the model was validated by adhesion of cumulus cells, the ability of the glycoprotein-beads to support spermatozoa binding and induce acrosome exocytosis. Thus, our findings document that ZP-beads provide a novel 3D tool to investigate the role of specific proteins on egg-sperm interactions becoming a relevant tool as a diagnostic predictor of mammalian sperm function once transferred to the industry.

scholarly journals Immunohistochemical localization of inhibin/activin alpha, betaA and betaB subunits and follistatin in bovine oocytes during in vitro maturation and fertilization

Reproduction ◽  
2003 ◽  
pp. 33-42 ◽  
Author(s):  
CC Silva ◽  
NP Groome ◽  
PG Knight
Keyword(s):  
Oocyte Maturation ◽  
Zona Pellucida ◽  
Cumulus Cells ◽  
Immunohistochemical Localization ◽  
Intense Staining ◽  
Immature Oocytes ◽  
Before And After ◽  
Alpha Beta ◽  
Quantitative Changes

The aim of this study was to evaluate the distribution of inhibin/activin alpha, beta(A) and beta(B) subunits and follistatin in immature oocytes and in matured oocytes before and after IVF. Denuded oocytes were submitted to a whole-mount immunofluorescence procedure. Specimens were imaged and fluorescent intensities quantified by scanning laser confocal microscopy. Immunoreactivity for inhibin alpha subunit (both alpha(C) and pro-alpha regions), abundant in the ooplasm of immature oocytes, decreased after maturation (a 68% and 88% decrease, respectively; P < 0.001), but increased after IVF by 2- and 5.7-fold, respectively (P < 0.01). Intense staining for beta(A) was detected in immature oocytes (predominantly in the outer ooplasm and zona pellucida) but after maturation and fertilization it was localized mainly in the zona pellucida, perivitelline space and oolemma. Immunoreactivity for beta(A) in the ooplasm decreased by 58% after maturation (P < 0.001) but increased again by 75% after fertilization (P < 0.01). Immunoreactivity for beta(B) was localized mainly in the zona pellucida and did not change after maturation. However, immunoreactivity for beta(B) was not detected in the zona pellucida after fertilization, but remained unchanged in unfertilized oocytes. Immunoreactivity for follistatin was detected in the ooplasm and zona pellucida of immature oocytes but decreased progressively in the ooplasm after maturation (a 63% decrease; P < 0.001) and did not change after IVF. Examination of partially denuded cumulus-oocyte complexes confirmed abundant expression of alpha(C), pro-alpha, beta(A) and follistatin immunoreactivity in cumulus cells, whereas beta(B) subunit staining was weak or absent in cumulus cells, but intense in the zona pellucida. In conclusion, the present study shows that qualitative and quantitative changes in the distribution of inhibin/activin subunits and follistatin accompany oocyte maturation and fertilization. The possibility, indicated by these observations, that activin A and activin B may play distinct roles in bovine oocyte maturation and fertilization warrants further study.

Clinically Meaningful Change

Methodology ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 97-105
Author(s):  
Rodrigo Ferrer ◽  
Antonio Pardo
Keyword(s):  
Effect Size ◽  
False Negative ◽  
False Negative Rate ◽  
Point Of View ◽  
Skewed Distribution ◽  
Effect Sizes ◽  
False Negatives ◽  
Large Size ◽  
Before And After ◽  
Post Test

Abstract. In a recent paper, Ferrer and Pardo (2014) tested several distribution-based methods designed to assess when test scores obtained before and after an intervention reflect a statistically reliable change. However, we still do not know how these methods perform from the point of view of false negatives. For this purpose, we have simulated change scenarios (different effect sizes in a pre-post-test design) with distributions of different shapes and with different sample sizes. For each simulated scenario, we generated 1,000 samples. In each sample, we recorded the false-negative rate of the five distribution-based methods with the best performance from the point of view of the false positives. Our results have revealed unacceptable rates of false negatives even with effects of very large size, starting from 31.8% in an optimistic scenario (effect size of 2.0 and a normal distribution) to 99.9% in the worst scenario (effect size of 0.2 and a highly skewed distribution). Therefore, our results suggest that the widely used distribution-based methods must be applied with caution in a clinical context, because they need huge effect sizes to detect a true change. However, we made some considerations regarding the effect size and the cut-off points commonly used which allow us to be more precise in our estimates.

Diversity of Primary Structures of the Carboxy-terminal Regions of Mammalian Fibrinogen Aα-Chains

1993 ◽  
Vol 69 (04) ◽  
pp. 351-360 ◽  
Author(s):  
Masahiro Murakawa ◽  
Takashi Okamura ◽  
Takumi Kamura ◽  
Tsunefumi Shibuya ◽  
Mine Harada ◽  
...  
Keyword(s):  
Amino Acid ◽  
Rhesus Monkey ◽  
Syrian Hamster ◽  
Tandem Repeats ◽  
Mammalian Species ◽  
Amino Acid Sequences ◽  
Point Of View ◽  
Cross Linking ◽  
Amino Terminal ◽  
Rgd Sequence

SummaryThe partial amino acid sequences of fibrinogen Aα-chains from five mammalian species have been inferred by means of the polymerase chain reaction (PCR). From the genomic DNA of the rhesus monkey, pig, dog, mouse and Syrian hamster, the DNA fragments coding for α-C domains in the Aα-chains were amplified and sequenced. In all species examined, four cysteine residues were always conserved at the homologous positions. The carboxy- and amino-terminal portions of the α-C domains showed a considerable homology among the species. However, the sizes of the middle portions, which corresponded to the internal repeat structures, showed an apparent variability because of several insertions and/or deletions. In the rhesus monkey, pig, mouse and Syrian hamster, 13 amino acid tandem repeats fundamentally similar to those in humans and the rat were identified. In the dog, however, tandem repeats were found to consist of 18 amino acids, suggesting an independent multiplication of the canine repeats. The sites of the α-chain cross-linking acceptor and α2-plasmin inhibitor cross-linking donor were not always evolutionally conserved. The arginyl-glycyl-aspartic acid (RGD) sequence was not found in the amplified region of either the rhesus monkey or the pig. In the canine α-C domain, two RGD sequences were identified at the homologous positions to both rat and human RGD S. In the Syrian hamster, a single RGD sequence was found at the same position to that of the rat. Triplication of the RGD sequences was seen in the murine fibrinogen α-C domain around the homologous site to the rat RGDS sequence. These findings are of some interest from the point of view of structure-function and evolutionary relationships in the mammalian fibrinogen Aα-chains.

Effect of ornidazole on fertility of male rats: inhibition of a glycolysis-related motility pattern and zona binding required for fertilization in vitro

Reproduction ◽  
2000 ◽  
pp. 127-135 ◽  
Author(s):  
W Bone ◽  
NG Jones ◽  
G Kamp ◽  
CH Yeung ◽  
TG Cooper
Keyword(s):  
Zona Pellucida ◽  
Glucose Utilization ◽  
Cumulus Cells ◽  
Glycolytic Enzyme ◽  
Male Rats ◽  
Fertilization In Vitro ◽  
Swimming Pattern ◽  
Principal Piece ◽  
Free Media

The effects of the male antifertility agent ornidazole on glycolysis as a prerequisite for fertilization were investigated in rats. Antifertility doses of ornidazole inhibited glycolysis within mature spermatozoa as determined from the lack of glucose utilization, reduced acidosis under anaerobic conditions and reduced glycolytic enzyme activity. As a consequence, cauda epididymidal spermatozoa from ornidazole-fed rats were unable to fertilize rat oocytes in vitro, with or without cumulus cells, which was not due to transfer of an inhibitor in epididymal fluid with the spermatozoa. Under IVF conditions, binding to the zona pellucida was reduced in spermatozoa from ornidazole-fed males and the spermatozoa did not undergo a change in swimming pattern, which was observed in controls. The block to fertilization could be explained by the disruption of glycolysis-dependent events, since reduced binding to the zona pellucida and a lack of kinematic changes were demonstrated by control spermatozoa in glucose-free media in the presence of respiratory substrates. The importance of glycolysis for binding to, and penetration of, the zona pellucida, and hyperactivation in rats is discussed in relation to the glycolytic production of ATP in the principal piece in which local deprivation of energy may explain the reduced force of spermatozoa from ornidazole-fed males.

Public Investment Criteria: Benefit-Cost Analysis for Planned Economic Growth by Stephen A. Marglin. London: George Allen & Unwin Ltd., 1967. pp.103. 22s. 6d.********** Investments for Capacity Expansion: Size, Location and Time-Phasing edited by Alan S. Manne. London: George Allen & Unwin Ltd., 1967. pp.239. 45s.Investments for Capacity Expansion: Size, Location and Time-Phasing edited by Alan S. Manne. London: George Allen & Unwin Ltd., 1967. pp.239. 45s.

1967 ◽  
Vol 7 (3) ◽  
pp. 416-420
Author(s):  
Arthur MacEwan
Keyword(s):  
Cost Benefit Analysis ◽  
Public Investment ◽  
Cost Benefit ◽  
Capacity Expansion ◽  
Point Of View ◽  
Systematic Analysis ◽  
Benefit Cost Analysis ◽  
The Government ◽  
The Many ◽  
Benefit Cost

These books are numbers 4 and 5, respectively, in the series "Studies in the Economic Development of India". The two books are interesting complements to one another, both being concerned with the analysis of projects within national plan formulation. However, they treat different sorts of problems and do so on very different levels. Marglin's Public Investment Criteria is a short treatise on the problems of cost-benefit analysis in an Indian type economy, i.e., a mixed economy in which the government accepts a large planning responsibility. The book, which is wholely theoretical, explains the many criteria needed for evaluation of projects. The work is aimed at beginning students and government officials with some training in economics. It is a clear and interesting "introduction to the special branch of economics that concerns itself with systematic analysis of investment alternatives from the point of view of a government".

THE METADIALOGUE CONCEPT IN ITS LINGUISTIC ASPECT

2019 ◽  
Vol 29 (5) ◽  
pp. 721-726
Author(s):  
Yu.V. Kupriyanova ◽  
I.M. Vasilyanova
Keyword(s):  
Subject Matter ◽  
Dynamic Structure ◽  
Point Of View ◽  
Semantic Relations ◽  
Human Cognition ◽  
Main Research ◽  
Key Points ◽  
Research Findings ◽  
The Subject ◽  
Linguistic Aspect

The article summarizes the key points in the development of the metadialogue phenomenon from a linguistic point of view. Some stages of the development of this concept and the difficulties associated with its structuring are covered. The main research findings of modern foreign and domestic experts on its study are considered. Some characteristics of the subject of the research from the standpoint of various pragmatic installations are given. On the basis of the dynamic structure of the metadialogue development, certain principles of semantic relations connected with the dialectical nature of human cognition are presented. Excursion into the history and evolution of the concept is presented. Several types of formulation of the subject matter are given. In accordance with the goal of speech exposure, internal problems of the development of metadialogue are highlighted and the critical points related to solving these problems are described. The rules of metadialogue flow are explained at the level of steps, the success/failure of which directly affects the final result of communication. The prospects of development of the concept research in accordance with various types of discourse are indicated.

Arthroscopy in Arthrosis: Is It Worth it? A case Presentation

2018 ◽  
Vol 69 (8) ◽  
pp. 2232-2235
Author(s):  
Marius Moga ◽  
Mark Edward Pogarasteanu ◽  
Antoine Edu
Keyword(s):  
Clinical Status ◽  
Loose Body ◽  
Point Of View ◽  
The Other ◽  
Joint Range Of Motion ◽  
Objective Evidence ◽  
Before And After ◽  
Total Knee ◽  
Joint Range

The role of arthroscopy in incipient and mild arthrosis, even combined with proximal tibial ostetomy, is well known and well documented. On the other hand, its role in the treatment of advanced arthrosis of the large joints, especially the knee, is a subject of controversy. The proponents of the use of arthroscopy in advanced arthrosis claim that meniscectomy, synovectomy, ostophytectomy, chondral lesion stabilization, arthroscopic release, plica and loose body removal greatly improve the quality of life for most patients, especially if followed by the use of viscoelastic injection, by diminishing pain and improving joint range of motion. The opponents claim that, even though the advantages are clear in the cases that refuse arthroplasty, in all the other cases the surgical indication should be total knee arthroplasty, as the clinical relief is temporary, but with all the risks of a surgical intervention. We have conducted an overview of the recent literature, in order to find objective evidence to sustain either point of view. We focused on articles published that included an objective measurement of before and after clinical status through clinical scores and objective measurements. We also focused on the follow-up period and on the evolution of the pathology after arthroscopy.

scholarly journals Systemic Lupus Erythematosus before and after COVID-19 Lockdown: How the Perception of Disease Changes through the Lenses of Narrative Medicine

Healthcare ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 726
Author(s):  
Fulvia Ceccarelli ◽  
Venusia Covelli ◽  
Giulio Olivieri ◽  
Francesco Natalucci ◽  
Fabrizio Conti
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Narrative Medicine ◽  
Good Control ◽  
Final Analysis ◽  
Point Of View ◽  
Systemic Lupus ◽  
Before And After ◽  
Text Content ◽  
Insight Into

Background: The COVID-19 pandemic contributes to the burden of living with different diseases, including Systemic Lupus Erythematosus (SLE). We described, from a narrative point of view, the experiences and perspectives of Italian SLE adults during the COVID-19 emergency, by distinguishing the illness experience before and after the lockdown. Methods: Fifteen patients were invited to participate. Illness narratives were collected between 22 and 29 March 2020 using a written modality to capture patients’ perspectives before and after the COVID-19 lockdown. We performed a two-fold analysis of collected data by distinguishing three narrative types and a qualitative analysis of content to identify the relevant themes and sub-themes reported. Results: Eight narratives included in the final analysis (mean length 436.9 words) have been written by eight females (mean age 43.3 ± 9.9 years, mean disease duration 13.1 ± 7.4 years). Six patients provided a quest narrative, one a chaos and the remaining one a restitution narrative. By text content analysis, we identified specific themes, temporally distinct before and after the lockdown. Before COVID-19, all the patients referred to a good control of disease, however the unexpected arrival of the COVID-19 emergency broke a balance, and patients perceived the loss of health status control, with anxiety and stress. Conclusions: We provided unique insight into the experiences of people with SLE at the time of COVID-19, underlining the perspective of patients in relation to the pandemic.

Sign in / Sign up

Export Citation Format

Share Document