Search results for "embryonic structures"
showing 10 items of 623 documents
Long-term fitness consequences of high yolk androgen levels: sons pay the costs
2012
Summary 1. Early growth conditions, for example hormonal environment during embryonic development, may have long-lasting effects on behaviour and phenotype, with subsequent fitness consequences. Yolk androgens have been shown to affect various offspring traits in the short-term, but fitness consequences for either offspring or parents, a prerequisite for studying the adaptiveness of this maternal effect, are poorly known in the wild. 2. We experimentally elevated yolk androgen levels of whole clutches in a wild population of collared flycatchers (Ficedula albicollis) and investigated the long-term effects of yolk androgens on offspring local recruitment, parental return rate, and timing and…
Influence of warming temperatures on coregonine embryogenesis within and among species
2021
The greatest response of lakes to climate change has been the increase in water temperatures on a global scale. The responses of many lake fishes to warming water temperatures are projected to be inadequate to counter the speed and magnitude of climate change, leaving some species vulnerable to decline and extinction. We experimentally evaluated the responses of embryos from a group of cold, stenothermic fishes (Salmonidae Coregoninae) - within conspecifics across lake systems, between congeners within the same lake system, and among congeners across lake systems - to a thermal gradient using an incubation method that enabled global comparisons. Study groups included cisco (Coregonus artedi…
Active hiding of social information from information-parasites
2014
Background: Coevolution between pairs of different kind of entities, such as providers and users of information, involves reciprocal selection pressures between them as a consequence of their ecological interaction. Pied flycatchers ( Ficedula hypoleuca ) have been shown to derive fitness benefits (larger clutches) when nesting in proximity to great tits ( Parus major ), presumably because they this way discover and obtain information about nesting sites. Tits suffer from the resulting association (smaller clutches). An arms race between the tits (information host) and the flycatchers (information parasite) could thus result . Great tits often cover eggs with nesting material before, but no…
How to escape from insect egg parasitoids : a review of potential factors explaining parasitoid absence across the Insecta
2020
The egg is the first life stage directly exposed to the environment in oviparous animals, including many vertebrates and most arthropods. Eggs are vulnerable and prone to mortality risks. In arthropods, one of the most common egg mortality factors is attack from parasitoids. Yet, parasitoids that attack the egg stage are absent in more than half of all insect (sub)orders. In this review, we explore possible causes explaining why eggs of some insect taxa are not parasitized. Many insect (sub)orders that are not attacked by egg parasitoids lack herbivorous species, with some notable exceptions. Factors we consider to have led to escape from egg parasitism are parental egg care, rapid egg deve…
Direct and transgenerational effects of an experimental heatwave on early life stages in a freshwater snail
2019
1. Global climate change imposes a serious threat to natural populations of many species. Estimates of the effects of climate change‐mediated environmental stresses are, however, often based only on their direct effects on organisms, and neglect the potential transgenerational (e.g. maternal) effects. 2. We tested whether high temperature (i.e. an experimental heatwave), which is known to reduce the performance of adult Lymnaea stagnalis snails, affects the produced offspring (eggs and hatchlings) through maternal effects, and how strong these effects are compared with the effects of direct exposure of offspring to high temperature. We examined the effect of maternal thermal environment (15…
Type of chromosome abnormality affects embryo morphology dynamics.
2016
Objective To study the differences in the cleavage time between types of embryo chromosomal abnormalities and elaborate algorithm to exclude aneuploid embryos according to the likelihood to be euploid. Design Retrospective cohort study. Setting University affiliated private center. Patient(s) Preimplantational genetic screening patients (n = 112) including cases of advanced maternal age, repeated implantation failure, and recurrent miscarriage. A total of 485 embryos were analyzed. Intervention(s) None. Main Outcome Measure(s) All biopsied embryos were cultured in an incubator with time-lapse technology, cleavage timing from insemination to day 3 and all kinetic parameters that have been de…
Transcriptomic behavior of genes associated with chromosome 21 aneuploidies in early embryo development.
2019
To analyze how chromosome 21 (HSA21) ploidy affects global gene expression of early human blastocysts.Prospective study.University-affiliated in vitro fertilization clinic.A total of 26 high-quality donated embryos from in vitro fertilization (IVF) patients: trisomy 21 (n = 8), monosomy 21 (n = 10), and euploid (n = 8) blastocysts.None.Blastocyst transcriptome changes and its associated functions.Trisomy 21, monosomy 21, and euploid blastocysts were classified by comparative genomic hybridization. The global transcriptome of whole blastocysts was analyzed with small cell number RNA sequencing, and they were compared to understand the gene expression behavior at early development and its imp…
Esophageal Atresia with or without Tracheoesophageal Fistula (EA/TEF): Association of Different EA/TEF Subtypes with Specific Co-occurring Congenital…
2017
Background Esophageal atresia with or without tracheoesophageal fistula (EA/TEF) represents the most common developmental malformation of the upper digestive tract. It is classified into six subtypes according to the classification of Vogt, depending on anatomical variation of this malformation. Around 50% of the patients with EA/TEF present additional anomalies, which often influence, next to the EA/TEF subtype, the overall prognosis of EA/TEF newborns. Here, we investigated the association of the different EA/TEF subtypes with co-occurring congenital anomalies in EA/TEF patients and demonstrate their implications for postnatal diagnostic workup. Materials and Methods We investigated 333 …
SOX2 expression diminishes with ageing in several tissues in mice and humans.
2017
SOX2 (Sex-determining region Y box 2) is a transcription factor expressed in several foetal and adult tissues and its deregulated activity has been linked to chronic diseases associated with ageing. Nevertheless, the level of SOX2 expression in aged individuals at the tissue level has not previously been examined. In this work, we show that SOX2 expression decreases significantly in the brain with ageing, in both humans and rodents. The administration of resveratrol for 6 months in mice partly attenuated this reduction. We also identified an age-related decline in SOX2 mRNA and protein expression in several other organs, namely, the lung, heart, kidney, spleen and liver. Moreover, periphera…
Severe pre-eclampsia is associated with alterations in cytotrophoblasts of the smooth chorion.
2016
Pre-eclampsia (PE), which affects ∼8% of first pregnancies, is associated with faulty placentation. Extravillous cytotrophoblasts (CTBs) fail to differentiate properly, contributing to shallow uterine invasion and deficient spiral artery remodeling. We studied the effects of severe PE (sPE) on the smooth chorion portion of the fetal membranes. The results showed a significant expansion of the CTB layer. The cells displayed enhanced expression of stage-specific antigens that extravillous CTBs normally upregulate as they exit the placenta. Transcriptomics revealed the dysregulated expression of many genes (e.g. placental proteins, markers of oxidative stress). We confirmed an sPE-related incr…