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The International Journal of... 2020Sexually reproducing organisms generate male and female haploid gametes, which meet and fuse at fertilization to produce a diploid zygote. The evolutionary process of... (Review)
Review
Sexually reproducing organisms generate male and female haploid gametes, which meet and fuse at fertilization to produce a diploid zygote. The evolutionary process of speciation is achieved and maintained by ensuring that gametes undergo productive fusion only within a species. In animals, hybrids from cross-species fertilization events may develop normally, but are usually sterile (Fitzpatrick, 2004). Metazoan sperm and eggs have several features to ensure that the gametes, which have evolved independently and also in conflict with each other, are competent to undergo fertilization (Firman, 2018). Fertilization is a specific process that is ideally supposed to result in randomized fusion of compatible egg and sperm. Here, I will discuss key processes driven by maternal factors in the egg that dictate earliest stages of gamete recognition, gamete choice and fusion in metazoans.
Topics: Animals; Biological Evolution; Female; Germ Cells; Male; Maternal Inheritance; Reproduction; Sperm-Ovum Interactions; Zygote
PubMed: 32659006
DOI: 10.1387/ijdb.190156sn -
Trends in Ecology & Evolution May 2023When biological material is transferred from one individual's body to another, as in ejaculate, eggs, and milk, secondary donor-produced molecules are often transferred... (Review)
Review
When biological material is transferred from one individual's body to another, as in ejaculate, eggs, and milk, secondary donor-produced molecules are often transferred along with the main cargo, and influence the physiology and fitness of the receiver. Both social and solitary animals exhibit such social transfers at certain life stages. The secondary, bioactive, and transfer-supporting components in socially transferred materials have evolved convergently to the point where they are used in applications across taxa and type of transfer. The composition of these materials is typically highly dynamic and context dependent, and their components drive the physiological and behavioral evolution of many taxa. Our establishment of the concept of socially transferred materials unifies this multidisciplinary topic and will benefit both theory and applications.
Topics: Animals; Sexual Behavior, Animal; Milk; Ovum; Semen
PubMed: 36543692
DOI: 10.1016/j.tree.2022.11.010 -
Advances in Anatomy, Embryology, and... 2016The acrosome, a single exocytotic vesicle on the head of sperm, has an essential role in fertilization, but the exact mechanisms by which it facilitates sperm-egg... (Review)
Review
The acrosome, a single exocytotic vesicle on the head of sperm, has an essential role in fertilization, but the exact mechanisms by which it facilitates sperm-egg interactions remain unresolved. The acrosome contains dozens of secretory proteins that are packaged into the forming structure during spermatogenesis; many of these proteins are localized into specific topographical areas of the acrosome, while others are more diffusely distributed. Acrosomal proteins can also be biochemically classified as components of the acrosomal matrix, a large, relatively insoluble complex, or as soluble proteins. This review focuses on recent findings using genetically modified mice (gene knockouts and transgenic "green acrosome" mice) to study the effects of eliminating acrosomal matrix-associated proteins on sperm structure and function. Some gene knockouts produce infertile phenotypes with obviously missing, specific activities that affect acrosome biogenesis during spermatogenesis or interfere with acrosome function in mature sperm. Mutations that delete some components produce fertile phenotypes with subtler effects that provide useful insights into acrosomal matrix function in fertilization. In general, these studies enable the reassessment of paradigms to explain acrosome formation and function and provide novel, objective insights into the roles of acrosomal matrix proteins in fertilization. The use of genetically engineered mouse models has yielded new mechanistic information that complements recent, important in vivo imaging studies.
Topics: Acrosome; Animals; Female; Fertilization; Gene Expression Regulation; Gene Knockout Techniques; Infertility, Male; Male; Membrane Fusion; Membrane Proteins; Mice; Mice, Transgenic; Mutation; Ovum; Peptide Hydrolases; Sperm Maturation
PubMed: 27194348
DOI: 10.1007/978-3-319-30567-7_2 -
Frontiers in Bioscience (Scholar... Jun 2017Fertilization is a hallmark event of sexual reproduction marked by the fusion of male and female gamete to form zygote. It is a highly complex, yet a robust process that... (Review)
Review
Fertilization is a hallmark event of sexual reproduction marked by the fusion of male and female gamete to form zygote. It is a highly complex, yet a robust process that is intricately regulated by various signalling molecules. A healthy fertilization is determined by the quality of zygote which is contingent on the health of egg and sperm. The relationship between infertility and gametic health can be reciprocal. On one hand gametogenesis has to be dynamic and unremitting to sustain the reproductive health, while on the other hand it has to be error free for proper embryonic development. Complex cellular interactions make gametogenesis highly vulnerable to extrinsic as well as intrinsic intrusions. Molecular disparities during these phases may result in complete fertilization failure. Present review provides an overview of the regulation of gametogenesis, determinants of healthy gamete, players at fertilization window and what may go wrong during the development of zygote to embryo leading to implantation failure. We have outlined different 'windows' of vulnerability during gametogenesis supported by evidences affecting the fertility potential of both the partners.
Topics: Animals; Female; Fertilization; Humans; Infertility; Male; Oogenesis; Ovum; Spermatogenesis; Spermatozoa
PubMed: 28410126
DOI: 10.2741/s494 -
Poultry Science Oct 2017Eggs and egg products form an integral part of the food chain. As such, research into egg structure, function, and production has made an important contribution to the... (Review)
Review
Eggs and egg products form an integral part of the food chain. As such, research into egg structure, function, and production has made an important contribution to the field of poultry science. The past decade has seen significant advances in avian egg science research, with work supplementing our understanding of the nature of the avian egg, and its biological, chemical, and physical properties. Eggshell color, strength, and chemical composition, poultry nutrition, and genetics have all been intensively studied recently, with significant progress being made in a number of these areas. Indeed, with the prevalence of robust theoretical techniques, it is now commonplace to combine experimental investigations with theory, providing a balanced and interdisciplinary perspective.
Topics: Animal Husbandry; Animals; Chickens; Eggs; Ovum; Poultry
PubMed: 28938769
DOI: 10.3382/ps/pex187 -
Advances in Experimental Medicine and... 2015The key, versatile role of intracellular Ca2+ signaling during egg activation after fertilization has been appreciated for several decades. More recently, evidence has... (Review)
Review
The key, versatile role of intracellular Ca2+ signaling during egg activation after fertilization has been appreciated for several decades. More recently, evidence has accumulated supporting the concept that cytoplasmic Ca2+ is also a major signaling nexus during subsequent development of the fertilized ovum. This chapter will review the molecular reactions that regulate intracellular Ca2+ levels and cell function, the role of Ca2+ signaling during egg activation and specific examples of repetitive Ca2+ signaling found throughout pre- and peri-implantation development. Many of the upstream and downstream pathways utilized during egg activation are also critical for specific processes that take place during embryonic development. Much remains to be done to elucidate the full complexity of Ca2+ signaling mechanisms in preimplantation embryos to the level of detail accomplished for egg activation. However, an emerging concept is that because this second messenger can be modulated downstream of numerous receptors and is able to bind and activate multiple cytoplasmic signaling proteins, it can help the coordination of development through up- and downstream pathways that change with each embryonic stage.
Topics: Blastocyst; Calcium; Calcium Signaling; Embryonic Development; Female; Fertilization; Gene Expression Regulation, Developmental; Humans; Inositol 1,4,5-Trisphosphate; Integrins; Male; Ovum; Platelet Activating Factor; Pregnancy; Spermatozoa
PubMed: 25956298
DOI: 10.1007/978-1-4939-2480-6_6 -
Cells Aug 2021Self-organization of and by the cytoskeleton is central to the biology of the cell. Since their introduction in the early 1980s, cytoplasmic extracts derived from the... (Review)
Review
Self-organization of and by the cytoskeleton is central to the biology of the cell. Since their introduction in the early 1980s, cytoplasmic extracts derived from the eggs of the African clawed-frog, , have flourished as a major experimental system to study the various facets of cytoskeleton-dependent self-organization. Over the years, the many investigations that have used these extracts uniquely benefited from their simplified cell cycle, large experimental volumes, biochemical tractability and cell-free nature. Here, we review the contributions of egg extracts to our understanding of the cytoplasmic aspects of self-organization by the microtubule and the actomyosin cytoskeletons as well as the importance of cytoskeletal filaments in organizing nuclear structure and function.
Topics: Actin Cytoskeleton; Animals; Cell Cycle; Cell Division; Cytoplasm; Cytoskeleton; Microtubules; Oocytes; Ovum; Xenopus laevis
PubMed: 34571847
DOI: 10.3390/cells10092197 -
Cold Spring Harbor Protocols Mar 2021Nearly a century ago, studies by Lancelot Hogben and others demonstrated that ovulation in female can be induced via injection of mammalian gonadotropins into the...
Nearly a century ago, studies by Lancelot Hogben and others demonstrated that ovulation in female can be induced via injection of mammalian gonadotropins into the dorsal lymph sac, allowing for egg production throughout the year independent of the normal reproductive cycles. Hormonally induced females are capable of producing thousands of eggs in a single spawning, which can then be fertilized to generate embryos or used as a substrate for generation of egg extracts. The protocol for induction of ovulation and subsequent egg collection is straightforward and robust, yet some of its details may vary among laboratories based on prior training, availability of necessary reagents, or the experimental objectives. As the goal of this protocol is not to describe every single variation possible for acquiring eggs but to provide a simple and clear description that can be easily applied by researchers with no prior working experience with , we focus on describing the method we use at the National Resource-that is, inducing ovulation in via dorsal lymph sac injection of gonadotropic hormones and the stimulation of egg laying through application of gentle pressure to the females.
Topics: Animals; Female; Gonadotropins; Ovum; Physiology; Xenopus laevis
PubMed: 33272976
DOI: 10.1101/pdb.prot106203 -
Philosophical Transactions of the Royal... Sep 2020Microorganisms are associated with the eggs of many animals. For some hosts, the egg serves as the ideal environment for the vertical transmission of beneficial... (Review)
Review
Microorganisms are associated with the eggs of many animals. For some hosts, the egg serves as the ideal environment for the vertical transmission of beneficial symbionts between generations, while some bacteria use the egg to parasitize their hosts. In a number of animal groups, egg microbiomes often perform other essential functions. The eggs of aquatic and some terrestrial animals are especially susceptible to fouling and disease since they are exposed to high densities of microorganisms. To overcome this challenge, some hosts form beneficial associations with microorganisms, directly incorporating microbes and/or microbial products on or in their eggs to inhibit pathogens and biofouling. Other functional roles for egg-associated microbiomes are hypothesized to involve oxygen and nutrient acquisition. Although some egg-associated microbiomes are correlated with increased host fitness and are essential for successful development, the mechanisms that lead to such outcomes are often not well understood. This review article will discuss different functions of egg microbiomes and how these associations have influenced the biology and evolution of animal hosts. This article is part of the theme issue 'The role of the microbiome in host evolution'.
Topics: Animals; Biological Evolution; Host Microbial Interactions; Invertebrates; Microbiota; Ovum; Symbiosis; Vertebrates
PubMed: 32772674
DOI: 10.1098/rstb.2019.0593 -
International Journal of Molecular... Mar 2021Mammalian 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... (Review)
Review
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.
Topics: Animals; Biomarkers; Cell Communication; Evolution, Molecular; Female; Gene Expression Regulation, Developmental; Male; Mammals; Oocytes; Ovum; Protein Transport; Spermatozoa; Zona Pellucida; Zona Pellucida Glycoproteins
PubMed: 33806989
DOI: 10.3390/ijms22063276