Search results for "Embryonic Structure"
showing 10 items of 624 documents
Other astacin homologs
2013
Publisher Summary This chapter describes the activity, specificity and structural chemistry of astacin homologs. The astacins are members of the metzincin superfamily such as the serralysins, the reprolysins/adamalysins, the matrixins, the leishmanolysins, the pregnancy-associated plasma proteins, the snapalysins and the fragilysins. Proteins of the hatching subfamily have been shown to be important for the cleavage of membranes coating developing embryos of invertebrates and vertebrates. Other members of this subfamily have varying or even several functions. UVS.2 from Xenopus, originally shown to play a role in dorso-anterior development, has been identified as the frog hatching enzyme. T…
Extreme Methylation Values of Imprinted Genes in Human Abortions and Stillbirths
2010
Imprinted genes play an important role in fetal and placental development. Using quantitative bisulfite pyrosequencing assays, we determined the DNA methylation levels at two paternally methylated (H19 and MEG3) and four maternally methylated (LIT1, NESP55, PEG3, and SNRPN) imprinted regions in fetal muscle samples from abortions and stillbirths. Two of 55 (4%) spontaneous abortions and 10 of 57 (18%) stillbirths displayed hypermethylation in multiple genes. Interestingly, none of 34 induced abortions had extreme methylation values in multiple genes. All but two abortions/stillbirths with multiple methylation abnormalities were male, indicating that the male embryo may be more susceptible t…
Gene expression during early embryogenesis of sea urchin: The histone and homeobox genes
1997
Transcriptional regulators are thought to play a key role in cell fate determination and territorial specification in sea urchin. Our goals are to clone transcription factors for studying embryonic development. One approach has been to use promoter binding and gene transfer technology to investigate the mechanisms of transcriptional activation and repression of the early H2A histone gene. By this analysis we identified a transcriptional activator, the MBF-1, that binds to the modulator element of the H2A gene and enhances the activity of the H2A promoter. However, the enhancer activity of the modulator and its interaction with MBF-1 also occurs at the gastrula stage when the early histone g…
261 INFLUENCE OF IN VITRO MATURATION ON EPIGENETIC MARKS AND GENE EXPRESSION IN BOVINE OOCYTES
2011
In cattle, in vitro maturation (IVM) of oocytes is an integral part of assisted reproduction technology. However, only 30% of in vitro matured bovine oocytes develop to the blastocyst stage after fertilization (compared with 60% for in vivo matured oocytes), indicating critical involvement of maturation conditions in the developmental competence of oocytes. Oocytes for IVF and intracytoplasmic sperm injection in humans are typically allowed to mature in vivo after superovulation because IVM is not considered to be a safe medical procedure. Several studies have shown that assisted reproduction technology involving prolonged in vitro culture of human and ruminant embryos can be associated wi…
Genetische Untersuchungen zur Inkompatibilität im Culex-pipiens-Komplex
1970
In crosses between populations of the mosquito Culex pipiens of different geographical origin three crossing types have been found (1) crosses with normal offspring (2) crosses with reduced offspring and (3) crosses that show almost total incompatibility. In the case of incompatible crosses 99.9% of the developing embryos are lethal and only about 0.1% of the embryos hatch and develop into fertile diploid females. The origin of the exceptional diploid females has been investigated by means of the marker genes Kuf, r, w, var, y and ru. These females develop from a diploid oocyte or from a diploid nucleus that originated by fusion of the pronucleus and the last polar body. This has been concl…
Hutchinson Gilford Progeria Syndrome: A Therapeutic Approach via Adenoviral Delivery of CRISPR/cas Genome Editing System
2015
Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare human genetic disease caused by mutations in the LMNA gene. LMNA codes for structural components of the nuclear lamina. Alterations of nuclear lamina lead to a very variable class of diseases known as laminopathies. In detail, HGPS manifests a severe premature ageing phenotype due to the accumulation of a dominant negative form of lamin-A called progerin. With current treatments, the life expectancy of HGPS patients does not exceed their second decade. Death is usually due to cardiovascular complications. Recently, a new technology for mammals in vivo gene editing has been developed: the clustered regularly interspaced short palindromic …
L-citrulline ameliorates pathophysiology in a rat model of superimposed preeclampsia
2021
AbstractPreeclampsia, characterized by hypertension, proteinuria, and fetal growth restriction, is one of the leading causes of maternal and perinatal mortality. By far, there is no effective pharmacological therapy for preeclampsia. The present study was conducted to investigate the effects of L-citrulline supplementation in Dahl salt-sensitive rat, a model of superimposed preeclampsia. Parental DSSR were treated with L-citrulline (2.5 g/L in drinking water) from the day of mating to the end of lactation period. Blood pressure of the rats was monitored throughout pregnancy and markers of preeclampsia were assessed. Endothelial function of the pregnant DSSR was assessed by wire myograph. L-…
The ontogeny of the filter apparatus of anuran larvae (Amphibia, Anura)
1991
The pharynx ofBufo calamita, Rana temporaria andBombina variegata larvae (larval Types IV and III) changes considerably during the latter part of embryonic development. The entodermal regions between the visceral pockets flatten inward to form the anlagen of the filter plates. The ectoderm thrusts forward from the area of the persistent epidermal gills overlying the anlagen of the filter plates. The esophagus pushes dorsolaterally into the pharynx to give rise to the ciliary cushions. Comparison with the development ofXenopus laevis (larval Type I) reveals shared characters: (1) the filter plates are overlapped by the sensory layer of the epiderm and (2) the ciliary grooves are, like the ci…
Turning waste into gold: Sustainable feed made of discards from the food industries promotes gonad development and colouration in the commercial sea …
2021
Abstract Development of sustainable aquaculture practices is a suitable solution to reduce the pressure on overexploited stocks of the Mediterranean sea urchin, Paracentrotus lividus, and to respond to the increasing market demand. To move forward the Blue Growth and following the principles of circular economy, a three-month feeding experiment was conducted to test a sustainable feed based on food processing discards on sea urchins. Two feed formulations differing on the proportions of the two main ingredients (endive outermost leaves and European anchovy discards in a ratio of 60:40 and 80:20 respectively) were prepared and tested on P. lividus gonad yield, development and quality. The re…
Short- and long-term population dynamical consequences of asymmetric climate change in black grouse
2006
Temporal asymmetry in patterns of regional climate change may jeopardize the match between the proximate and ultimate cues of the timing of breeding. The consequences on short- and long-term population dynamics and trends as well as the underlying mechanisms are, however, often unknown. Using long-term data from Finland, we demonstrate that black grouse ( Tetrao tetrix ) have responded to spring warming by advancing both egg-laying and hatching. However, early summer (the time of hatching) has not advanced, and chicks have to face colder post-hatching conditions. Demonstrating that these conditions are critical to post-hatching survival, we show that chicks are increasingly suffering highe…