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Fertility and Sterility Sep 1988ZIFT offers the embryologic follow-up of fertilization combined with the advantage of natural tubal transport of embryos to the uterus. Comparing ZIFT pregnancy data to...
ZIFT offers the embryologic follow-up of fertilization combined with the advantage of natural tubal transport of embryos to the uterus. Comparing ZIFT pregnancy data to the patients' failed IVF-ET cycles, it is premature to conclude that these pregnancies were exclusively due to the early intrafallopian transfer of zygotes, but the results are encouraging.
Topics: Adult; Fallopian Tubes; Female; Fertilization in Vitro; Humans; Infertility; Male; Pregnancy; Zygote
PubMed: 3410103
DOI: 10.1016/s0015-0282(16)60145-0 -
Current Opinion in Obstetrics &... Oct 1993It is well over a decade since the birth of the first test-tube baby and still the in-vitro conditions for early embryonic development remain suboptimal. The ideal... (Review)
Review
It is well over a decade since the birth of the first test-tube baby and still the in-vitro conditions for early embryonic development remain suboptimal. The ideal culture medium to increase longevity and improve viability of human embryos is not available. Since the metabolic requirements of the human embryo changes from one cleavage stage to another, the development of a single culture medium for all stages could not be expected. The use of helper cells (coculture) in vitro offers much promise as there are numerous documentations in both man and animals describing their ability to increase blastulation rates and improve embryo viability. This paper reviews the effect of coculture on human zygote development. The selection and establishment of cell-lines, biologic actions of coculture of gametes and zygotes, the outcome, and future prospects are discussed.
Topics: Cell Line; Cells, Cultured; Cleavage Stage, Ovum; Cryopreservation; Culture Media, Conditioned; Fallopian Tubes; Female; Fertilization in Vitro; Forecasting; Gamete Intrafallopian Transfer; Humans; Male; Pregnancy; Pregnancy Outcome; Pregnancy, Multiple; Zygote
PubMed: 8241433
DOI: No ID Found -
Current Topics in Developmental Biology 2015In Caenorhabditis elegans, the first zygotic transcription can be detected in the 4-cell stage C. elegans embryo, a little over 2h after fertilization. However, early... (Review)
Review
In Caenorhabditis elegans, the first zygotic transcription can be detected in the 4-cell stage C. elegans embryo, a little over 2h after fertilization. However, early development until the onset of gastrulation at approximately the 28-cell stage takes place normally even in the absence of zygotic transcription. Therefore, posttranslational and posttranscriptional regulation of the maternal proteins and mRNAs, respectively, that are loaded into the developing oocytes is sufficient to direct development prior to gastrulation. Protein phosphorylation is extensively used throughout the C. elegans maternal-to-zygotic transition (MZT): (1) for maternal protein activation, (2) for coordination of the meiotic and mitotic cell cycle, (3) to mark specific proteins for degradation, and/or (4) to switch the biochemical activity of specific proteins. Maternally loaded mRNAs are regulated primarily by a set of maternal RNA-binding proteins (RBPs), each of which binds to sometimes overlapping target sequences within the mRNA 3'UTRs and either promotes or inhibits translation. Most maternal transcripts are uniformly distributed throughout the embryo but specific transcripts are translated only in certain blastomeres. This control is achieved by the asymmetric distribution of the maternal RBPs, such that the blastomere-specific constellation of RBPs present, and their relative levels, determines the translational readout for their target transcripts. In certain well-studied cases, such as the specification of the sole endodermal precursor in the 8-cell embryo, the maternal transcripts and proteins along with their directly targeted zygotic genes have been identified.
Topics: Animals; Caenorhabditis elegans; Embryo, Nonmammalian; Female; Fertilization; Gene Expression Regulation, Developmental; Models, Biological; Zygote
PubMed: 26358869
DOI: 10.1016/bs.ctdb.2015.06.001 -
Biochemistry. Biokhimiia Dec 2015Events, manifesting transition from maternal to zygotic period of development are studied for more than 100 years, but underlying mechanisms are not yet clear. We... (Review)
Review
Events, manifesting transition from maternal to zygotic period of development are studied for more than 100 years, but underlying mechanisms are not yet clear. We provide a brief historical overview of development of concepts and explain the specific terminology used in the field. We further discuss differences and similarities between the zygotic genome activation and in vitro reprogramming process. Finally, we envision the future research directions within the field, where biochemical methods will play increasingly important role.
Topics: Animals; Embryonic Stem Cells; Gene Expression Regulation, Developmental; Genome; Humans; Zygote
PubMed: 26878577
DOI: 10.1134/S0006297915130088 -
Journal of Assisted Reproduction and... Nov 2021
Topics: Animals; Embryonic Development; Humans; Mammals; Zygote
PubMed: 34796415
DOI: 10.1007/s10815-021-02360-5 -
Current Opinion in Genetics &... Aug 2011In all animals, a key event in the transition from maternal control of development to control by products of the zygotic genome is the elimination of a significant... (Review)
Review
In all animals, a key event in the transition from maternal control of development to control by products of the zygotic genome is the elimination of a significant fraction of the mRNAs loaded into the egg by the mother. Clearance of these maternal mRNAs is accomplished by two activities: the first is maternally encoded while the second requires zygotic transcription. Recent advances include identification of RNA-binding proteins that function as specificity factors to direct the maternal degradation machinery to its target mRNAs; small RNAs-most notably microRNAs-that function as components of the zygotically encoded activity; signaling pathways that trigger production and/or activation of the clearance mechanism in early embryos; and mechanisms for spatial control of transcript clearance.
Topics: Animals; Gene Expression Regulation, Developmental; Humans; Maternal-Fetal Relations; RNA Processing, Post-Transcriptional; RNA, Messenger; RNA, Messenger, Stored; Transcription, Genetic; Zygote
PubMed: 21497081
DOI: 10.1016/j.gde.2011.03.003 -
Current Opinion in Plant Biology Feb 2019Plant embryogenesis initiates with the fusion of sperm and egg cell, and completes the generation of the basic outline of the future plant. Here, we summarize the recent... (Review)
Review
Plant embryogenesis initiates with the fusion of sperm and egg cell, and completes the generation of the basic outline of the future plant. Here, we summarize the recent findings about the signaling cascade triggering the zygotic transcription, and the intracellular events and regulatory factors involved in the formation of the two major body axes. We highlight the lack of systematic de novo transcriptional activation in the zygote, and emphasize the importance of cytoskeletal reorganization to polarize the zygote and control the first asymmetric division that establishes the apical-basal axis. Finally, the limited knowledge of mechanisms that control the cell divisions separating the inner and outer cell layers is summarized and we propose approaches to enhance our understanding of basic principles of plant embryogenesis.
Topics: Body Patterning; Gene Expression Regulation, Plant; Models, Biological; Seeds; Transcription, Genetic; Zygote
PubMed: 30223185
DOI: 10.1016/j.pbi.2018.08.005 -
Current Topics in Developmental Biology 2015
Topics: Animals; Embryonic Development; Female; Humans; Zygote
PubMed: 26358880
DOI: 10.1016/S0070-2153(15)00076-9 -
Genetics Oct 2023The zygote has a daunting task ahead of itself; it must develop from a single cell (fertilized egg) into a fully functioning adult with a multitude of different cell... (Review)
Review
The zygote has a daunting task ahead of itself; it must develop from a single cell (fertilized egg) into a fully functioning adult with a multitude of different cell types. In the beginning, the zygote has help from its mother, in the form of gene products deposited into the egg, but eventually, it must rely on its own resources to proceed through development. The transfer of developmental control from the mother to the embryo is called the maternal-to-zygotic transition (MZT). All animals undergo this transition, which is defined by two main processes-the degradation of maternal RNAs and the synthesis of new RNAs from the zygote's own genome. Here, we review the regulation of the MZT in Drosophila, but given the broad conservation of this essential process, much of the regulation is shared among metazoans.
Topics: Animals; Zygote; Drosophila; Gene Expression Regulation, Developmental; Genome; RNA, Messenger; RNA; Embryonic Development
PubMed: 37616526
DOI: 10.1093/genetics/iyad142 -
Fertility and Sterility Aug 1989This study describes the zygote intrafallopian transfer treatment in patients with unexplained infertility. After retrieval, the oocytes were inseminated with 80,000...
This study describes the zygote intrafallopian transfer treatment in patients with unexplained infertility. After retrieval, the oocytes were inseminated with 80,000 progressive motile sperm cells per milliliter. If fertilization occurred, a maximum of three zygotes were replaced by laparoscopy in the fimbrial end of one healthy fallopian tube. A pregnancy rate of 48.1% per zygote intrafallopian transfer replacement was obtained. Seventeen pregnancies are actually ongoing, two patients delivered, and seven patients miscarried. Even after replacing a maximum of three zygotes, there were 6 twin and 2 triplet pregnancies.
Topics: Adult; Embryo, Mammalian; Fallopian Tubes; Female; Freezing; Humans; Infertility; Pregnancy; Preservation, Biological; Reproductive Techniques; Zygote
PubMed: 2666176
DOI: 10.1016/s0015-0282(16)60850-6