scholarly journals The role of mammalian foetal membranes in early embryogenesis: Lessons from marsupials

2020 ◽  
Author(s):  
Anthony M. Carter
Keyword(s):  
Early Embryogenesis ◽  
Foetal Membranes

Role of Auxin in Early Embryogenesis of Plants

2014 ◽  
Vol 48 (4) ◽  
pp. 371-380
Author(s):  
Song Lizhen ◽  
Wang Yi ◽  
Yang Qinghua ◽  
Cheng Youfa
Keyword(s):  
Early Embryogenesis

The role of neurohumours in early embryogenesis

Development ◽  
1970 ◽  
Vol 23 (3) ◽  
pp. 549-569
Author(s):  
G. A. Buznikov ◽  
A. N. Kost ◽  
N. F. Kucherova ◽  
A. L. Mndzhoyan ◽  
N. N. Suvorov ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Functional Activity ◽  
Early Onset ◽  
Active Sites ◽  
Physiological Effect ◽  
Early Embryogenesis ◽  
Dopamine Synthesis ◽  
Direct Involvement ◽  
Misgurnus Fossilis

In previous papers (Buznikov, Chudakova & Zvezdina, 1964; Buznikov, Chudakova, Berdysheva & Vyazmina, 1968) we reported that fertilized eggs of the sea-urchin Strongylocentrotus dröbachiensis synthesized a number of neurohumours, such as serotonin (5-hydroxytryptamine, 5-HT), acetylcholine (ACh), adrenalin (A), noradrenalin (NA) and dopamine. Synthesis of 5-HT was also demonstrated in the fertilized eggs of the loach Misgurnus fossilis and some marine Invertebrata. In experiments with sea-urchin embryos we were able to trace regular changes in the level of 5-HT, ACh, A and NA, related to the first cleavage divisions. This early onset of neurohumour synthesis, as well as regular changes in their level, suggests their direct involvement in the regulation of the first cleavage divisions. The functional activity of neurohumours (M) in adult organisms is realized through their reaction with the active sites of corresponding receptors (R) according to the following equation:The magnitude of the physiological effect under certain conditions is linearly proportional to the number of complexes MR formed (Turpayev, 1962; Ariëns, 1964).

Chromatin Diminution in Cyclops kolensis Lill. (Copepoda, Crustacea) as a Radical Way to Inactivate Redundant Genome in Somatic Cells

2018 ◽  
Vol 156 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Andrey K. Grishanin ◽  
Maxim V. Zagoskin
Keyword(s):  
Chromosome Number ◽  
Repetitive Sequences ◽  
Early Embryogenesis ◽  
Chromosome Size ◽  
Chromatin Diminution ◽  
Elimination Process ◽  
Dna Elimination ◽  
Molecular Studies ◽  
Cyclops Kolensis

Chromatin diminution (CD) is a phenomenon of programmed DNA elimination which takes place in early embryogenesis in some eukaryotes. The mechanism and biological role of CD remain largely unknown. During CD in the freshwater copepod Cyclops kolensis, the genome of cells of the somatic lineage is reorganized and reduced in size by more than 90% without affecting the genome of germline cells. Although the diploid chromosome number is unchanged, chromosome size is dramatically reduced by CD. The eliminated DNA consists primarily of repetitive sequences and localizes within granules during the elimination process. In this review, we provide an overview of CD in C. kolensis including both cytological and molecular studies.

ROLE OF THE OVIDUCT DURING EARLY EMBRYOGENESIS

1993 ◽  
Vol 28 (3) ◽  
pp. 189-192 ◽  
Author(s):  
F. Gandolfi ◽  
T. A. L. Brevini ◽  
S. Modina ◽  
R. Bianchi ◽  
L. Passoni
Keyword(s):  
Early Embryogenesis

scholarly journals The role of ZFP57 and additional KRAB-zinc finger proteins in the maintenance of human imprinted methylation and multi-locus imprinting disturbances

2020 ◽  
Vol 48 (20) ◽  
pp. 11394-11407
Author(s):  
Ana Monteagudo-Sánchez ◽  
Jose Ramon Hernandez Mora ◽  
Carlos Simon ◽  
Adam Burton ◽  
Jair Tenorio ◽  
...  
Keyword(s):  
Zinc Finger ◽  
Expression Profiling ◽  
Zinc Finger Proteins ◽  
Early Embryogenesis ◽  
Mouse Embryos ◽  
Parental Origin ◽  
Embryonic Genome ◽  
Repressor Complex ◽  
Genome Activation

Abstract Genomic imprinting is an epigenetic process regulated by germline-derived DNA methylation that is resistant to embryonic reprogramming, resulting in parental origin-specific monoallelic gene expression. A subset of individuals affected by imprinting disorders (IDs) displays multi-locus imprinting disturbances (MLID), which may result from aberrant establishment of imprinted differentially methylated regions (DMRs) in gametes or their maintenance in early embryogenesis. Here we investigated the extent of MLID in a family harbouring a ZFP57 truncating variant and characterize the interactions between human ZFP57 and the KAP1 co-repressor complex. By ectopically targeting ZFP57 to reprogrammed loci in mouse embryos using a dCas9 approach, we confirm that ZFP57 recruitment is sufficient to protect oocyte-derived methylation from reprogramming. Expression profiling in human pre-implantation embryos and oocytes reveals that unlike in mice, ZFP57 is only expressed following embryonic-genome activation, implying that other KRAB-zinc finger proteins (KZNFs) recruit KAP1 prior to blastocyst formation. Furthermore, we uncover ZNF202 and ZNF445 as additional KZNFs likely to recruit KAP1 to imprinted loci during reprogramming in the absence of ZFP57. Together, these data confirm the perplexing link between KZFPs and imprint maintenance and highlight the differences between mouse and humans in this respect.

scholarly journals Lipid Rafts: Keys to Sperm Maturation, Fertilization, and Early Embryogenesis

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Natsuko Kawano ◽  
Kaoru Yoshida ◽  
Kenji Miyado ◽  
Manabu Yoshida
Keyword(s):  
Cell Membrane ◽  
Cell Signaling ◽  
Membrane Fusion ◽  
Lipid Rafts ◽  
Gene Transcription ◽  
Early Embryogenesis ◽  
Sperm Maturation ◽  
Protein Receptors ◽  
Structure And Functions

Cell membranes are composed of many different lipids and protein receptors, which are important for regulating intracellular functions and cell signaling. To orchestrate these activities, the cell membrane is compartmentalized into microdomains that are stably or transiently formed. These compartments are called “lipid rafts”. In gamete cells that lack gene transcription, distribution of lipids and proteins on these lipid rafts is focused during changes in their structure and functions such as starting flagella movement and membrane fusion. In this paper, we describe the role of lipid rafts in gamete maturation, fertilization, and early embryogenesis.

scholarly journals The role of maternal CREB in early embryogenesis of Xenopus laevis

2003 ◽  
Vol 261 (2) ◽  
pp. 337-352 ◽  
Author(s):  
Nambirajan Sundaram ◽  
Qinghua Tao ◽  
Chris Wylie ◽  
Janet Heasman
Keyword(s):  
Xenopus Laevis ◽  
Early Embryogenesis

Hormonal responses during early embryogenesis in maize

2014 ◽  
Vol 42 (2) ◽  
pp. 325-331 ◽  
Author(s):  
Junyi Chen ◽  
Andreas Lausser ◽  
Thomas Dresselhaus
Keyword(s):  
Early Embryogenesis ◽  
Hormonal Response ◽  
Two Component System ◽  
Hormonal Responses ◽  
Embryo Patterning ◽  
Auxin Signalling ◽  
Model Plant Arabidopsis Thaliana ◽  
Endosperm Formation ◽  
Cytokinin Response

Plant hormones have been shown to regulate key processes during embryogenesis in the model plant Arabidopsis thaliana, but the mechanisms that determine the peculiar embryo pattern formation of monocots are largely unknown. Using the auxin and cytokinin response markers DR5 and TCSv2 (two-component system, cytokinin-responsive promoter version #2), as well as the auxin efflux carrier protein PIN1a (PINFORMED1a), we have studied the hormonal response during early embryogenesis (zygote towards transition stage) in the model and crop plant maize. Compared with the hormonal response in Arabidopsis, we found that detectable hormone activities inside the developing maize embryo appeared much later. Our observations indicate further an important role of auxin, PIN1a and cytokinin in endosperm formation shortly after fertilization. Apparent auxin signals within adaxial endosperm cells and cytokinin responses in the basal endosperm transfer layer as well as chalazal endosperm are characteristic for early seed development in maize. Moreover, auxin signalling in endosperm cells is likely to be involved in exogenous embryo patterning as auxin responses in the endosperm located around the embryo proper correlate with adaxial embryo differentiation and outgrowth. Overall, the comparison between Arabidopsis and maize hormone response and flux suggests intriguing mechanisms in monocots that are used to direct their embryo patterning, which is significantly different from that of eudicots.

Evidence for cleavage of [26-14C]cholesterol side-chain by human foetal membranes in vitro

1983 ◽  
Vol 102 (2) ◽  
pp. 288-291 ◽  
Author(s):  
R. Gunasegaram ◽  
A. Loganath ◽  
K. L. Peh ◽  
S. C. Ng ◽  
S. M. M. Karim ◽  
...  
Keyword(s):  
Isotope Dilution ◽  
Strong Evidence ◽  
Side Chain ◽  
Isotope Dilution Analysis ◽  
Spontaneous Labour ◽  
Foetal Membranes

Abstract. With a view to establish the hitherto undescribed role of cholesterol in foetal-membranous steroidogenesis, homogenates of term chorion pars reflexa and amnion pars reflexa and pars placentaris collected from 6 women after spontaneous labour at term (38 to 41 weeks gestation) were incubated with [26-14C]cholesterol. Using reverse-isotope dilution analysis, [14C]isocaproic acid was isolated and characterized. This conversion constitutes strong evidence that C-20, 22-desmolase activity, normally present in the adrenal, gonadal and placental tissues, is present in the homogenates of both membranes. The efficiency of the enzymic conversion suggests that the chorion possesses a more active desmolase system compared to that of the amnion.

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