Search results for "Embryo"

Functional Genomics of 5-to 8-Cell Stage Human Embryos by Blastomere Single-Cell cDNA Analysis

2010

Blastomere fate and embryonic genome activation (EGA) during human embryonic development are unsolved areas of high scientific and clinical interest. Forty-nine blastomeres from 5- to 8-cell human embryos have been investigated following an efficient single-cell cDNA amplification protocol to provide a template for high-density microarray analysis. The previously described markers, characteristic of Inner Cell Mass (ICM) (n = 120), stemness (n = 190) and Trophectoderm (TE) (n = 45), were analyzed, and a housekeeping pattern of 46 genes was established. All the human blastomeres from the 5- to 8-cell stage embryo displayed a common gene expression pattern corresponding to ICM markers (e.g., …

Specific expression of a TRIM-containing factor in ectoderm cells affects the skeletal morphogenetic program of the sea urchin embryo

2011

In the indirect developing sea urchin embryo, the primary mesenchyme cells (PMCs) acquire most of the positional and temporal information from the overlying ectoderm for skeletal initiation and growth. In this study, we characterize the function of the novel gene strim1, which encodes a tripartite motif-containing (TRIM) protein, that adds to the list of genes constituting the epithelial-mesenchymal signaling network. We report that strim1 is expressed in ectoderm regions adjacent to the bilateral clusters of PMCs and that its misexpression leads to severe skeletal abnormalities. Reciprocally, knock down of strim1 function abrogates PMC positioning and blocks skeletogenesis. Blastomere tran…

The dynamics of structural modifications of mitochondria at the early stages of sea urchin embryonic development

1992

The organization of the chondriome and the ultrastructure of mitochondria have been studied in eggs and embryos of the sea urchin Paracentrotus lividus. The egg chondriome is characterized by an arrangement in well-delimited clusters. Analysis of mitochondrial clusters on electron micrographs of ultrathin serial sections shows two kinds of mitochondria of different shapes, the rod-shaped and the spherical. The egg mitochondria have a dense matrix and a well-ordered arrangement of cristae which, in rod-shaped variety, are perpendicular to the major axis. Cell division is accompanied by significant changes in intracellular distribution of mitochondria and in their structure. At the stage of 2…

Human stem cells from single blastomeres reveal pathways of embryonic or trophoblast fate specification.

2015

Mechanisms of initial cell fate decisions differ among species. To gain insights into lineage allocation in humans, we derived ten human embryonic stem cell lines (designated UCSFB1-10) from single blastomeres of four 8-cell embryos and one 12-cell embryo from a single couple. Compared with numerous conventional lines from blastocysts, they had unique gene expression and DNA methylation patterns that were, in part, indicative of trophoblast competence. At a transcriptional level, UCSFB lines from different embryos were often more closely related than those from the same embryo. As predicted by the transcriptomic data, immunolocalization of EOMES, T brachyury, GDF15 and active β-catenin reve…

Expression of homeobox-containing genes in the sea urchin (Parancentrotus lividus) embryo

1994

Two homeobox-containing genes that belong to different homeodomain classes have been isolated from a sea urchin geonomic library. One, PlHbox11, is the sea urchin homologue of the human and mouse Hox B3 gene, the other, PlHbox12, shows about 55% identity with paired class genes. Expression profile analysis of the two sea urchin Hbox genes suggests that they play different roles during embryogenesis. In fact, PlHbox11 transcripts are rare and are detected only in the pluteus larva and in the Aristotle's lantern and intestine of the adult. The PlHbox12 gene is, on the contrary, transiently expressed in the very early embryo already at the four cell stage; it accumulates at the 64 cell stage a…

Is the nuclear status of an embryo an independent factor to predict its ability to develop to term?

2012

Objective To determine the prognostic impact of the embryo nuclear status at day 2 among other major morphologic parameters (first cleavage at day 1, number of blastomeres and anuclear fragmentation at day 2) on the birth rate. Design Retrospective study. Setting Hospital IVF department. Patient(s) Women undergoing 1,629 day 2 transfers of 2,732 embryos from May 2006 to November 2008. Intervention(s) Four groups according to the embryo nuclear status. Main Outcome Measure(s) Implantation, miscarriage, and birth rates. Result(s) Univariate analysis indicated significantly higher birth rates when all blastomeres were mononucleated (15.0%) compared with embryos with not all blastomeres mononuc…

Blood cells and the biosynthesis of hemocyanin in Sepia embryos.

2004

Microwave effects on isolated chick embryo hearts.

1986

This study was designed to examine the effects of microwaves on the electric activity of hearts as a means of elucidating interactive mechanisms of nonionizing radiation with cardiac tissue. Experiments were performed on isolated hearts of 9-12-day-old chick embryos placed in small petri dishes. Oxygenated isotonic Ringer's solution at 37 degrees C permitted heart survival. Samples were irradiated at 2.45 GHz with a power density of 3 mW/cm2. The heart signal was detected with a glass micropipet inserted into the sinoatrial node and examined by means of a Berg-Fourier analyzer. Pulsed microwaves caused the locking of the heartbeat to the modulation frequency, whereas continuous wave irradia…

Stably BDNF-GFP expressing embryonic stem cells exhibit a BDNF release-dependent enhancement of neuronal differentiation

2013

Brain-derived neurotrophic factor (BDNF) is known to be a crucial regulator of neuronal survival and synaptic plasticity in the mammalian brain. Furthermore, BDNF positively influences differentiation of embryonic neural precursors as well as of neural stem cells from adult neurogenic niches. To study the impact of cell-released BDNF on neural differentiation of embryonic stem cells (ESCs), which represent an attractive source for cell transplantation studies, we have generated BDNF-GFP overexpressing mouse ESC clones by knock-in technology. After neural differentiation in vitro, we observed that BDNF-GFP overexpressing ESC clones gave rise to an increased number of neurons as compared to c…

Effects of thrombin and of the phospholipase C inhibitor, D609, on the vascularity of the chick chorioallantoic membrane.

2000

Abstract Microvascular corrosion casting was used to assess the effects of thrombin and D609, a phospholipase C inhibitor, on the vascularity of the chick embryo chorioallantoic membrane (CAM). Discs containing vehicle, thrombin or D609 were placed on the CAM of fertilized white Leghorn eggs on Day 9 of gestation and vascularity was assessed on Day 11. Thrombin caused significant increases in the numbers (43%), diameters (5%) and lengths (17%), of both pre- and postcapillaries (first-order vessels by centripetal ordering). Conversely, D609 caused a decrease in the numbers (27%), lengths (12%) and diameters (8%) of first-order vessels. D609 decreased the total vascular volume of first- to th…