Search results for "Embryonic Development"
showing 10 items of 86 documents
A biochemical study of the effects of tributyltin on unfertilized eggs, embryos and larvae of the sea squirt Ciona intestinalis
2009
We have used unfertilized eggs, embryos and larvae of the sea squirt Ciona intestinalis (Ascidiacea, Urochordata) to study the effects of tributyltin (TBT) on acetylcholine esterase (AChE) activity. Our results showed an increase of AChE enzyme activity levels after TBT exposure in both unfertilized eggs and embryos. The effects of TBT were more pronounced during the gastrula stage, while no differences between exposed larvae and controls were observed. A mechanism of TBT action on enzyme activity during ascidian embryonic development and the possibility of employing AChE in C. intestinalis as a biomarker of TBT exposure are suggested and discussed.
dfh is a Drosophila homolog of the Friedreich's ataxia disease gene
2000
Abstract A putative Drosophila homolog of the Friedreich's ataxia disease gene (FRDA) has been cloned and characterized; it has been named Drosophila frataxin homolog (dfh). It is located at 8C/D position on X chromosome and is spread over 1 kb, a much smaller genomic region than the human gene. Its genomic organization is simple, with a single intron dividing the coding region into two exons. The predicted encoded product has 190 amino acids, being considered a frataxin-like protein on the basis of the sequence and secondary structure conservation when compared with human frataxin and related proteins from other eukaryotes. The closest match between the Drosophila and the human proteins in…
Sustained activation of mTOR pathway in embryonic neural stem cells leads to development of tuberous sclerosis complex-associated lesions
2011
SummaryTuberous Sclerosis Complex (TSC) is a multisystem genetic disorder characterized by hamartomatous neurological lesions that exhibit abnormal cell proliferation and differentiation. Hyperactivation of mTOR pathway by mutations in either the Tsc1 or Tsc2 gene underlies TSC pathogenesis, but involvement of specific neural cell populations in the formation of TSC-associated neurological lesions remains unclear. We deleted Tsc1 in Emx1-expressing embryonic telencephalic neural stem cells (NSCs) and found that mutant mice faithfully recapitulated TSC neuropathological lesions, such as cortical lamination defects and subependymal nodules (SENs). These alterations were caused by enhanced gen…
The inhibitory effect of D-glucosamine on thymidine kinase in chick embryo retinas and HeLa cells
1984
D-Glucosamine markedly inhibits thymidine incorporation into the TCA-insoluble fraction and thymidine kinase activity in HeLa cells. Both the inhibitory effects are also observed in isolated retinas of chick embryos. In this case the inhibitory effects are age-dependent and the magnitude of the responses decreases with embryonic development. In addition the time of exposure to D-glucosamine which is necessary to reveal the inhibitory effect on thymidine kinase increases with the age of the embryos.
The influence of adult worm age and definitive host on the transmission of Echinostoma caproni: egg hatchability and miracidial infectivity.
2012
AbstractWe analysed the influence of different ages of Echinostoma caproni adult worms reared in different definitive host-species on egg hatchability and miracidial infectivity. Eggs obtained from 2-, 4- and 6-week-old adult worms collected from rats, hamsters and mice, hatched miracidia that were used to infect laboratory-reared specimens of Biomphalaria glabrata. Highest egg hatchability was obtained with eggs derived from hamsters and mice. Egg hatchability did not seem to be affected by the age of E. caproni adult worms. Miracidial infectivity was not affected by the definitive host species. However, miracidial infectivity was affected by the age of adult worms when they developed in t…
Rapid changes in heat-shock cognate 70 levels, heat-shock cognate phosphorylation state, heat-shock transcription factor, and metal transcription fac…
2010
The aim of the present study was to analyze and compare the effects of several metals on the embryos of the sea urchin Paracentrotus lividus, a key species within the Mediterranean Sea ecosystem. Embryos were continuously exposed from fertilization to the following metals: 0.6 mg/l copper, 3 mg/l lead, and 6 mg/l nickel. The embryos were then monitored for metal responses at the gastrula stage, which occurred 24 h after exposure. A biochemical multi-experimental approach was taken and involved the investigation of the levels of HSC70 expression and the involvement of heat shock factor (HSF) and/or metal transcription factor (MTF) in the response. Immunoblotting assays and electrophoretic mo…
Beneficial Effect of Two Culture Systems with Small Groups of Embryos on the Development and Quality of In Vitro-Produced Bovine Embryos
2014
Summary Currently, in vitro-produced embryos derived by ovum pick up (OPU) and in vitro fertilization (IVF) technologies represent approximately one-third of the embryos worldwide in cattle. Nevertheless, the culture of small groups of embryos from an individual egg donor is an issue that OPU-IVF laboratories have to face. In this work, we tested whether the development and quality of the preimplantation embryos in vitro cultured in low numbers (five embryos) could be improved by the addition of epidermal growth factor, insulin, transferrin and selenium (EGF-ITS) or by the WOW system. With this aim, immature oocytes recovered from slaughtered heifers were in vitro matured and in vitro ferti…
The increase in maternal expression of axin1 and axin2 contribute to the zebrafish mutant ichabod ventralized phenotype.
2014
β-Catenin is a central effector of the Wnt pathway and one of the players in Ca(+)-dependent cell-cell adhesion. While many wnts are present and expressed in vertebrates, only one β-catenin exists in the majority of the organisms. One intriguing exception is zebrafish that carries two genes for β-catenin. The maternal recessive mutation ichabod presents very low levels of β-catenin2 that in turn affects dorsal axis formation, suggesting that β-catenin1 is incapable to compensate for β-catenin2 loss and raising the question of whether these two β-catenins may have differential roles during early axis specification. Here we identify a specific antibody that can discriminate selectively for β-…
Embryonic development of corkwing wrasse, Symphodus melops
2016
Master's thesis Aquatic Ecology BIO500 - University of Agder 2016 Eggs from corkwing wrasse, Symphodus melops were described, photographed and illustrated to characterise the embryonic development of this species. Egg development was divided into 8 stages from fertilisation until hatching with descriptions of key features for each stage. The rate of development in corkwing wrasse eggs at temperatures commonly found along the Norwegian coast (12, 15 and 18 C) was also investigated. The rate of development was faster at higher temperatures. Keywords: labridae, cleaner fish, embryonic development, corkwing wrasse
Progenitor death drives retinal dysplasia and neuronal degeneration in a mouse model of Atrip-Seckel syndrome
2020
ABSTRACT Seckel syndrome is a type of microcephalic primordial dwarfism (MPD) that is characterized by growth retardation and neurodevelopmental defects, including reports of retinopathy. Mutations in key mediators of the replication stress response, the mutually dependent partners ATR and ATRIP, are among the known causes of Seckel syndrome. However, it remains unclear how their deficiency disrupts the development and function of the central nervous system (CNS). Here, we investigated the cellular and molecular consequences of ATRIP deficiency in different cell populations of the developing murine neural retina. We discovered that conditional inactivation of Atrip in photoreceptor neurons …