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Frontiers in Cell and Developmental... 2021Fertilization is one of the most important events in living organisms to generate a new life with a mixed genetic background. To achieve successful fertilization, sperm... (Review)
Review
Fertilization is one of the most important events in living organisms to generate a new life with a mixed genetic background. To achieve successful fertilization, sperm and eggs must undergo complex processes in a sequential order. Fertilization of marine invertebrate type has been studied for more than a hundred years. Ascidian sperm are attracted by chemoattractants from eggs and bind to the vitelline coat. Subsequently, sperm penetrate through the vitelline coat proteolytically and finally fuse with the egg plasma membrane. Here, we summarize the fertilization mechanisms of ascidians, particularly from sperm-egg interactions to sperm penetration of the egg coat. Since ascidians are hermaphrodites, inbreeding depression is a serious problem. To avoid self-fertilization, ascidians possess a self-incompatibility system. In this review, we also describe the molecular mechanisms of the self-incompatibility system in type A governed by three allelic gene pairs of and .
PubMed: 35186958
DOI: 10.3389/fcell.2021.827214 -
Cells Dec 2021The vitelline layer (VL) of a sea urchin egg is an intricate meshwork of glycoproteins that intimately ensheathes the plasma membrane. During fertilization, the VL plays...
The vitelline layer (VL) of a sea urchin egg is an intricate meshwork of glycoproteins that intimately ensheathes the plasma membrane. During fertilization, the VL plays important roles. Firstly, the receptors for sperm reside on the VL. Secondly, following cortical granule exocytosis, the VL is elevated and transformed into the fertilization envelope (FE), owing to the assembly and crosslinking of the extruded materials. As these two crucial stages involve the VL, its alteration was expected to affect the fertilization process. In the present study, we addressed this question by mildly treating the eggs with a reducing agent, dithiothreitol (DTT). A brief pretreatment with DTT resulted in partial disruption of the VL, as judged by electron microscopy and by a novel fluorescent polyamine probe that selectively labelled the VL. The DTT-pretreated eggs did not elevate the FE but were mostly monospermic at fertilization. These eggs also manifested certain anomalies at fertilization: (i) compromised Ca signaling, (ii) blocked translocation of cortical actin filaments, and (iii) impaired cleavage. Some of these phenotypic changes were reversed by restoring the DTT-exposed eggs in normal seawater prior to fertilization. Our findings suggest that the FE is not the decisive factor preventing polyspermy and that the integrity of the VL is nonetheless crucial to the egg's fertilization response.
Topics: Actins; Animals; Calcium; Dithiothreitol; Embryonic Development; Fertilization; Ovum; Sea Urchins
PubMed: 34944081
DOI: 10.3390/cells10123573 -
Open Biology Aug 2021Egg activation is a series of highly coordinated processes that prepare the mature oocyte for embryogenesis. Typically associated with fertilization, egg activation...
Egg activation is a series of highly coordinated processes that prepare the mature oocyte for embryogenesis. Typically associated with fertilization, egg activation results in many downstream outcomes, including the resumption of the meiotic cell cycle, translation of maternal mRNAs and cross-linking of the vitelline membrane. While some aspects of egg activation, such as initiation factors in mammals and environmental cues in sea animals, have been well-documented, the mechanics of egg activation in insects are less well-understood. For many insects, egg activation can be triggered independently of fertilization. In , egg activation occurs in the oviduct resulting in a single calcium wave propagating from the posterior pole of the oocyte. Here we use physical manipulations, genetics and live imaging to demonstrate the requirement of a volume increase for calcium entry at egg activation in mature oocytes. The addition of water, modified with sucrose to a specific osmolarity, is sufficient to trigger the calcium wave in the mature oocyte and the downstream events associated with egg activation. We show that the swelling process is regulated by the conserved osmoregulatory channels, aquaporins and DEGenerin/Epithelial Na channels. Furthermore, through pharmacological and genetic disruption, we reveal a concentration-dependent requirement of transient receptor potential M channels to transport calcium, most probably from the perivitelline space, across the plasma membrane into the mature oocyte. Our data establish osmotic pressure as a mechanism that initiates egg activation in and are consistent with previous work from evolutionarily distant insects, including dragonflies and mosquitos, and show remarkable similarities to the mechanism of egg activation in some plants.
Topics: Animals; Calcium; Calcium Signaling; Drosophila Proteins; Drosophila melanogaster; Embryonic Development; Female; Fertilization; Oocytes; Osmolar Concentration
PubMed: 34343463
DOI: 10.1098/rsob.210067 -
International Journal of Molecular... Jun 2021Early changes in hemocyte proteins in freshwater crayfish , in response to an injection with the fungal pattern recognition protein β-1,3-glucan (laminarin) were...
Early changes in hemocyte proteins in freshwater crayfish , in response to an injection with the fungal pattern recognition protein β-1,3-glucan (laminarin) were investigated, as well as changes after saline (vehicle) injection and in naïve animals. Injection of saline resulted in rapid recruitment of granular hemocytes from surrounding tissues, whereas laminarin injection on the other hand induced an initial dramatic drop of hemocytes. At six hours after injection, the hemocyte populations therefore were of different composition. The results show that mature granular hemocytes increase in number after saline injection as indicated by the high abundance of proteins present in granular cell vesicles, such as a vitelline membrane outer layer protein 1 homolog, mannose-binding lectin, masquerade, crustin 1 and serine protease homolog 1. After injection with the β-1,3-glucan, only three proteins were enhanced in expression, in comparison with saline-injected animals and uninjected controls. All of them may be associated with immune responses, such as a new and previously undescribed Kazal proteinase inhibitor. One interesting observation was that the clotting protein was increased dramatically in most of the animals injected with laminarin. The number of significantly affected proteins was very few after a laminarin injection when compared to uninjected and saline-injected crayfish. This finding may demonstrate some problematic issues with gene and protein expression studies from other crustaceans receiving injections with pathogens or pattern recognition proteins. If no uninjected controls are included and no information about hemocyte count (total or differential) is given, expressions data for proteins or mRNAs are very difficult to properly interpret.
Topics: Animals; Arthropod Proteins; Astacoidea; Biomarkers; Gene Expression; Hemocytes; Proteome; Proteomics; RNA, Messenger; beta-Glucans
PubMed: 34208769
DOI: 10.3390/ijms22126464 -
Animals : An Open Access Journal From... Mar 2021The yolk is the principal part of the egg that contains vitamins, minerals, lipids, and proteins which are essential for embryo development and hatching. The egg yolk...
The yolk is the principal part of the egg that contains vitamins, minerals, lipids, and proteins which are essential for embryo development and hatching. The egg yolk contains significant amounts of lipoproteins, triacylglycerides, and cholesterol, whose dynamics are indistinct during embryogenesis. The effects of cholesterol on the yolk protein abundance, intensity, and function are ill-defined during embryonic development. Using two-dimensional gel electrophoresis, eggs with respective high and low cholesterol protein abundance were investigated after 0, 2, 6, and 13 days of embryogenesis and further analyzed by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry. The results revealed that the vitellogenin proteins are the most abundant egg yolk protein that showed proximity and a high degree of variation in isoelectric point and molecular weight. The results demonstrated increased expression of vitellogenin-1 and vitellogenin-3 at two days and vitellogenin-2 protein at 13 days of embryogenesis in both egg types. The ovoinhibitor, immunoglobulin lambda light chain precursor, Ig-gamma (clone-36 chicken), and beta-2-glycoprotein-1 precursor proteins were significantly expressed in high cholesterol eggs while haptoglobin protein PIT-54 and vitelline membrane outer layer proteins intensities were significant in low cholesterol eggs at two days of embryogenesis. The high cholesterol eggs showed a modest increase in egg weight, yolk weight, albumen height, yolk color, and egg strength relative to the low cholesterol eggs. The gene ontology enrichment analysis revealed that the differentially expressed proteins such as vitellogenin proteins were involved in lipid transport and lipid localization biological processes and showed nutrient reservoir activity function. The ovotransferrin regulated the biological processes of plasminogen activation and extracellular matrix disassembly and characterized the anchored component of the plasma membrane. The ovoinhibitor protein was involved in response to mineralocorticoid and corticosterone biological processes whereas the vitellin membrane outer layer protein constituted the extracellular exosome, extracellular organelle, and membrane-bounded vesicle cellular components. Collectively, our study revealed yolk protein abundance, molecular function, cellular components, and biological processes and concluded that yolk protein intensities were significantly altered by cholesterol concentration.
PubMed: 33803097
DOI: 10.3390/ani11030744 -
Poultry Science Apr 2021The aim of the experiment was to evaluate the potential use of citric acid as a modifier of quality changes in table eggs during their storage. About 780 table hen eggs...
The aim of the experiment was to evaluate the potential use of citric acid as a modifier of quality changes in table eggs during their storage. About 780 table hen eggs were collected on the same day. They were numbered individually and placed on trays 30 pcs on each. Control group (CA0) consisted of eggs unmodified with any additional substances. In experimental groups CA10 and CA15, eggshells were sprayed with the aqueous solution of citric acid (10 and 15% concentration, respectively). At the start of the experiment, only quality traits of eggs from the control group were analyzed. The remaining eggs were stored at 14°C and 70% RH (typical storage conditions). Their quality was evaluated after 7, 14, 21, and 28 d. The depth of the air cell, egg weight and specific gravity, traits of shell (permeability, strength, weight, thickness, density), and egg content (pH of yolk and albumen, Haugh units, yolk weight and color) were evaluated each time. The use of citric acid decreased the severity of qualitative changes. Citric acid-treated eggs demonstrated smaller weight loss, shallower air cell, higher structural albumen, less-intensive water diffusion from albumen to yolk indicating the improved resistance of the vitelline membrane. Owing to the fact that citric acid is accepted and recognized as a safe food preservative is a relatively cheap and available substance, it seems that it can be used to inhibit quality changes in table eggs during their storage.
Topics: Animals; Chickens; Citric Acid; Egg Shell; Eggs; Food Handling; Food Preservatives; Vitelline Membrane
PubMed: 33610892
DOI: 10.1016/j.psj.2021.01.018 -
Scientific Reports Nov 2020In this study, we aimed to perform structural and proteomic analysis of the vitelline membrane (VM) of two species birds belonging to the family Turdidae: blackbird...
In this study, we aimed to perform structural and proteomic analysis of the vitelline membrane (VM) of two species birds belonging to the family Turdidae: blackbird (Turdus merula) and song thrush (Turdus philomelos). We performed structural analyses using scanning electron microscopy. The VM proteins were identified and compared to the best-known chicken VM proteins. According to our results, VM of both species has a typical three-layered structure: the outer layer, inner layer, and the continuous membrane between them. An unusual observation was the finding of "convexity" formed by the inner layer in blackbird. The role of these convex structures is not known, but they can be typical for the species and can be used in their identification. In addition, we identified two proteins in the VM of both species of birds, of which U3KEZ1 FICAL was not previously identified in any other bird species, and the U3JXV8 FICAL protein was confirmed only once in cockatiel parrot VM. The function of these proteins is not exactly known, but their structure shows similarities to the SERPIN proteins that are involved in microbiological defense, i.e., they are immune proteins. This study contributes to the current knowledge about the structure and composition of proteins of VM, especially because similar analyses have never been performed for Turdidae family. Knowledge of the structure and specific proteins of blackbird and song thrush VM can be beneficial in research on ecology and bird biology and also helpful in developing noninvasive and nongenetic identification methods.
Topics: Animals; Chickens; Egg Proteins; Egg Yolk; Female; Immune System; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Proteome; Songbirds; Species Specificity; Vitelline Membrane
PubMed: 33168893
DOI: 10.1038/s41598-020-76559-4 -
Poultry Science Sep 2020A study was conducted to determine differences between Histomonas meleagridis-infected and control pullets based on disease signs, hen growth, and egg production and...
A study was conducted to determine differences between Histomonas meleagridis-infected and control pullets based on disease signs, hen growth, and egg production and quality. Ross 708SF females were weighed and then placed in pens on the day of hatch (92 chicks/pen). At 25 D, 4 pens were infected with H. meleagridis in the cloaca, whereas 4 pens were control. At 5, 10, and 20 D after inoculation, 5 birds per pen (2 birds per pen at 20 D) were subjectively scored for blackhead disease. Birds were feed restricted based on BW and/or egg production. Individual BW were collected at 3, 5, 13, 15, 20, and 64 wk. Egg production was recorded at 24-63 wk. Egg quality was measured at 30, 34, 39, 42, and 56 wk and included shell and vitelline membrane strength, shell thickness, egg weight, and Haugh units. Hatchability was measured at 27, 37, and 60 wk and fertility at 27 and 37 wk. Treatment effects were determined by JMP Pro 14 using GLM with means separated using the Student t test (P ≤ 0.05). Cecal lesions were apparent on 5, 10, and 20 D and liver lesions on 10 and 20 D for the infected birds. The control had no histomoniasis lesions. Flock uniformity differed on wk 13 and 20 (P = 0.04; 0.04). Infected birds weighed less at 64 wk (P = 0.002). The onset of lay was not delayed. Infected birds produced more eggs during 1 period (P = 0.02). The infected birds produced heavier eggs at 30 wk (P = 0.04), eggs with a stronger and thicker shell at 42 wk (P = 0.05, 0.03), and eggs with a stronger vitelline membrane at 56 wk (P = 0.049). Hatchability and fertility did not differ (P > 0.05). H. meleagridis was observed in the infected birds' cecal samples at trial termination. This study indicates early infection with H. meleagridis has limited effects on pullet egg production and quality.
Topics: Animals; Body Weight; Chickens; Female; Fertility; Oviposition; Poultry Diseases; Protozoan Infections, Animal; Trichomonadida
PubMed: 32867968
DOI: 10.1016/j.psj.2020.05.020 -
International Journal of Biological... Dec 2020The chicken egg vitelline membrane (CEVM) is an important structure for the transmembrane transport of egg yolk components, protection of the blastodisc, and separation...
The chicken egg vitelline membrane (CEVM) is an important structure for the transmembrane transport of egg yolk components, protection of the blastodisc, and separation of egg white and egg yolk. In this study, the N-glycoproteome of the CEVM was mapped and analyzed in depth. Total protein of the CEVM was digested, and the glycopeptides were enriched by a hydrophilic interaction liquid chromatography microcolumn and identified by nano liquid chromatography/tandem mass spectrometry. A total of 435 N-glycosylation sites on 208 N-glycoproteins were identified in CEVM. Gene Ontology enrichment analysis showed that CEVM N-glycoproteins are mainly involved in the regulation of proteinases/inhibitors and transmembrane transport of lipids. Mucin-5B is the primary N-glycoprotein in the CEVM. Comparison of the main N-glycoproteins between the CEVM and other egg parts revealed the tissue specificity of N-glycosylation of egg proteins. The results provide insights into protein N-glycosylation in the chicken egg, CEVM functions and underlying mechanisms.
Topics: Animals; Chickens; Chromatography, Liquid; Egg Proteins; Gene Ontology; Glycoproteins; Mucin-5B; Tandem Mass Spectrometry; Vitelline Membrane
PubMed: 32860793
DOI: 10.1016/j.ijbiomac.2020.08.193 -
Molecular Reproduction and Development Mar 2020Fertilization by more than one sperm causes polyploidy, a condition that is generally lethal to the embryo in the majority of animal species. To prevent this occurrence,... (Review)
Review
Fertilization by more than one sperm causes polyploidy, a condition that is generally lethal to the embryo in the majority of animal species. To prevent this occurrence, eggs have developed a series of mechanisms that block polyspermy at the level of the plasma membrane or their extracellular coat. In this review, we first introduce the mammalian egg coat, the zona pellucida (ZP), and summarize what is currently known about its composition, structure, and biological functions. We then describe how this specialized extracellular matrix is modified by the contents of cortical granules (CG), secretory organelles that are exocytosed by the egg after gamete fusion. This process releases proteases, glycosidases, lectins and zinc onto the ZP, resulting in a series of changes in the properties of the egg coat that are collectively referred to as hardening. By drawing parallels with comparable modifications of the vitelline envelope of nonmammalian eggs, we discuss how CG-dependent modifications of the ZP are thought to contribute to the block to polyspermy. Moreover, we argue for the importance of obtaining more information on the architecture of the ZP, as well as systematically investigating the many facets of ZP hardening.
Topics: Animals; Exocytosis; Female; Glycosylation; Humans; Lectins; Male; Mice; Oocytes; Polyploidy; Sperm-Ovum Interactions; Spermatozoa; Zinc; Zona Pellucida; Zona Pellucida Glycoproteins
PubMed: 32003503
DOI: 10.1002/mrd.23320