Ribosomal ribonucleic acid synthesis in Rana pipiens embryos
Ribosomal ribonucleic acid synthesis in frog embryos
EMBRYO↗
SEARCH · Engineering Papers
Results for “embryo”
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Microgravity in the STS-29 space shuttle discovery affected the vestibular system of chick embryos
Out of 32 embryos flown (16 @ E2 + 16 @ E9) for 5 days, 16 survived. All sixteen E2 were dead at landing. Eight were opened and eight were incubated at 1.0G. Autopsy showed that 4 E2 survived over 24 hours in space. Eight E14 hatched without anatomical malformations, and 8 E14 were fixed. The height of the macular epithelia was 31 mu m (mean) in control and 26 mu m in flight chicks. The cross-sectional area of macular nuclei of control was 17 mu m(2) for hair cells and 14 mu m(2) in supporting cells. In flight, cross-sectional area was 17 mu m(2) in hair cells and 15 mu m(2) in supporting cells (n=250). The shape factor of cartilage cells (1.0 = perfect circle) between control (mean = 0.70) and flight (mean = 0.72), and the area of cartilaginous cells between controls (mean = 9 mu m(2)) and flight (mean = 9 mu m(2)) did not differ (n=300). The nuclei of support cells were closer to the basement membrane in flight than in control chicks. The immunoreactivity of otoconia with anti keratan, fibronectin or chrondroitin sulfate was not different between flight and control ears. There were more afferent fibers inside the macular epithelia of flight (p<0.05) than control. Three of 8 flight animals had elevated vestibular thresholds (VT), with normal mean response amplitudes and latencies. Modified afferent innervation patterns requiring weeks to compensate are sufficient to elevate VT, and should be investigated further. Other reversible (sublethal) microgravity effects on sensory epithelia (vacuoles, swelling, etc) require quantification.
Flight Experiment↗
Effects of Dissolved Organic Carbon on Copper Toxicity to Embryos of Mytilus galloprovincialis as Measured by Diffusive Gradient in Thin Films
Diffusive Gradient in Thin-film (DGT), a passive sampling method, has the potential to better quantify the bioavailable fraction of Cu in seawater, when determining toxicological endpoints, versus grab samples evaluated for total or dissolved Cu. In the present study, laboratory exposure of DGTs and Mediterranean mussel (M. galloprovincialis) embryos at varying concentrations of dissolved organic carbon (DOC) and Cu were performed to resolve the degree to which mimicry of toxicity-buffering occurs in passive sampler quantification. Studies were performed in water collected from Sequim Bay, Washington, USA, spiked with Suwannee River Natural Organic Matter (SRNOM) and Cu(II)SO4. The results provide preliminary EC50s ranging from 4.8 to 11.5 µg/L as CDGT Cu over the span of 0.892 to 8.28 mg/L DOC. M. galloprovincialis was selected as the relevant organism for this correlation based on current consensus for deriving water criteria values, which are based solely from Mytilus spp. toxicological study final acute values, maintaining the intent of protecting environmental and commercial interests to the fauna regarded as most sensitive to Cu input in the marine environment. The present study provides an initial DGT response by which coastal DOC pools with varying functional binding group mixtures can be compared to discern the applicability of broad use for quantifying biological effects at time scales integrated to account for pulsed-input to marine waters.
copper, Bioavailability, Diffusive Gradient in Thi↗
Connecting suborganismal data to bioenergetic processes: killifish embryos exposed to a dioxin-like compound
A core challenge for ecological risk assessment is to integrate molecular responses into a chain of causality to organismal or population level outcomes. Bioenergetic theory may be a useful approach for integrating suborganismal responses to predict organismal level responses that influence population dynamics. In this work, we describe a novel application of Dynamic Energy Budget (DEB), theory in the context of a toxicity framework (Adverse Outcome Pathways, AOP) to make quantitative predictions of chemical exposures to individuals, starting from suborganismal data. We use early life stage exposure of Fundulus heteroclitus to dioxin-like chemicals (DLCs) and connect AOP Key Events (KEs) to DEB processes through “damage” that is produced at a rate proportional to the internal toxicant concentration. We use transcriptomic data of fish embryos exposed to DLCs to translate molecular indicators of damage into changes in DEB parameters (damage increases somatic maintenance costs) and use DEB models to predict sublethal and lethal effects of young fish. By changing a small subset of model parameters, we predict the evolved tolerance to DLCs in some wild F. heteroclitus populations, a data set not used in model parameterization. The differences in model parameters points to reduced sensitivity and altered damage repair dynamics as contributing to this evolved resistance. Our methodology has potential extrapolation to untested chemicals of ecological concern.
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
Expression and effects of TSP50 in mouse embryo and cardiac myocyte development
Highlights: • TSP50 expression increases during early embryonic development. • TSP50 expression decreases during embryonic heart and P19 myocardial development. • Higher or lower TSP50 causes abnormal zygote and P19 myocardial differentiation. TSP50, a testis-specific gene encoding a serine protease-like protein, was specifically expressed in the spermatocytes of testes but abnormally activated and expressed in many different kinds of cancers. Here, we aimed to analyze the expression of TSP50 in mouse embryo and its function in early embryonic development. Firstly, the distribution of TSP50 in oocytes and embryonic development was characterized by immunofluorescence, RT-PCR and western blotting, and the results showed that TSP50 was detected at all studied stages with a dynamic expression pattern. When overexpressed TSP50 in zygotes by microinjection, the zygotes development was highly accelerated. On the contrary, knocking down TSP50 expression by RNA interference greatly retarded the zygote development. Furthermore, TSP50 expression at embryonic day 6.5 (E6.5), day 8.5 (E8.5) and day 10.5 (E10.5) were increasingly enhanced, However, the expression of TSP50 decreased gradually in the development and differentiation of cardiac myocyte from E12.5 to postnatal (P0). Additionally, we found that TSP50 expression was decreased during cardiac myocyte differentiation of P19 cells. Overexpression of TSP50 could decrease the expression of GATA-4, and knockdown of TSP50 markedly increase the expression of GATA-4. Taken together, our data indicate that TSP50 may play an important role during the process of mouse embryonic development as well as myocardial cell differentiation.
60 APPLIED LIFE SCIENCES↗
Somatic mutations reveal asymmetric cellular dynamics in the early human embryo
Somatic cells acquire mutations throughout the course of an individual’s life. Mutations occurring early in embryogenesis are often present in a substantial proportion of, but not all, cells in postnatal humans and thus have particular characteristics and effects. Depending on their location in the genome and the proportion of cells they are present in, these mosaic mutations can cause a wide range of genetic disease syndromes and predispose carriers to cancer. They have a high chance of being transmitted to offspring as de novo germline mutations and, in principle, can provide insights into early human embryonic cell lineages and their contributions to adult tissues. Although it is known that gross chromosomal abnormalities are remarkably common in early human embryos, our understanding of early embryonic somatic mutations is very limited. Here we use whole-genome sequences of normal blood from 241 adults to identify 163 early embryonic mutations. We estimate that approximately three base substitution mutations occur per cell per cell-doubling event in early human embryogenesis and these are mainly attributable to two known mutational signatures. We used the mutations to reconstruct developmental lineages of adult cells and demonstrate that the two daughter cells of many early embryonic cell-doubling events contribute asymmetrically to adult blood at an approximately 2:1 ratio. As a result, this study therefore provides insights into the mutation rates, mutational processes and developmental outcomes of cell dynamics that operate during early human embryogenesis.
59 BASIC BIOLOGICAL SCIENCES↗
High pressure suppression of plasticity due to an overabundance of shear embryo formation
Abstract High pressure shear band formation is a critical phenomenon in energetic materials due to its influence on both mechanical strength and mechanochemical activation. While shear banding is known to occur in a variety of these materials, the governing dynamics of the mechanisms are not well defined for molecular crystals. We conduct molecular dynamics simulations of shock wave induced shear band formation in the energetic material 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) to assess shear band nucleation processes. We find, that at high pressures, the initial formation sites for shear bands, “embryos”, form in excess and rapidly lower deviatoric stresses prior to shear band formation and growth. This results in the suppression of plastic deformation. A local cluster analysis is used to quantify and contrast this mechanism with a more typical shear banding seen at lower pressures. These results demonstrate a mechanism that is reversible in nature and that supersedes shear band formation at increased pressures. We anticipate that these results will have a broad impact on the modeling and development of high-strain rate application materials such as those for high explosives and hypersonic systems.
36 MATERIALS SCIENCE↗
An embryo of protocells: The capsule of graphene with selective ion channels
In this study, the synthesis of artificial cell is a route for searching the origin of protocell. Here, we create a novel cell model of graphene capsules with selective ion channels, indicating that graphene might be an embryo of protocell membrane. Firstly, we found that the highly oxidized graphene and phospholipid-graphene oxide composite would curl into capsules under a strongly acidic saturated solution of heavy metallic salt solution at low temperature. Secondly, L-amino acids exhibited higher reactivity than D-amino acids on graphene oxides to form peptides, and the formed peptides in the influence of graphene would be transformed into a secondary structure, promoting the formation of left-handed proteins. Lastly, monolayer nanoporous graphene, prepared by unfocused 84 Kr 25+ , has a high selectivity for permeation of the monovalent metal ions ( Rb + > K + > Cs + > Na + > Li + , based on permeation concentration), but does not allow Cl- go through. It is similar to K+ channels, which would cause an influx of K + into capsule of graphene with the increase of pH in the primitive ocean, creating a suitable inner condition for the origin of life. Therefore, we built a model cell of graphene, which would provide a route for reproducing the origin of life.
59 BASIC BIOLOGICAL SCIENCES↗
Trp53 deficient mice predisposed to preterm birth display region-specific lipid alterations at the embryo implantation site
Here we demonstrate that conditional deletion of mouse uterine Trp53 (p53d/d), molecularly linked to mTORC1 activation and causally linked to premature uterine senescence and preterm birth, results in aberrant lipid signatures within the heterogeneous cell types of embryo implantation sites on day 8 of pregnancy. In situ nanospray desorption electrospray ionization mass spectrometry imaging (nano-DESI MSI) was used to characterize the molecular speciation of free fatty acids, monoacylglycerols, unmodified and oxidized phosphatidylcholine (PC/Ox-PC), and diacylglycerol (DG) species within implantation sites of p53d/d mice and floxed littermates. Implantation sites from p53d/d mice exhibited distinct spatially resolved changes demonstrating accumulation of DG species, depletion of Ox-PC species, and increase in species with more unsaturated acyl chains, including arachidonic and docosahexaenoic acid. Understanding abnormal changes in the abundance and localization of individual lipid species early in the progression to premature birth is important for discovering novel targets for treatments and diagnosis.
Environmental Molecular Sciences Laboratory↗
Calculation of critical nucleation rates by the persistent embryo method: application to quasi hard sphere models
Here, we study the crystal nucleation of the Weeks–Chandler–Andersen (WCA) model, using the recently introduced persistent embryo method (PEM). The method provides detailed characterization of pre-critical, critical and post-critical nuclei, as well as nucleation rates that compare favorably with those obtained using other methods (umbrella sampling, forward flux sampling or seeding). We further map our results to a hard sphere model allowing comparison with other existing predictions. Implications for experiments are also discussed.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Two promoters integrate multiple enhancer inputs to drive wild-type knirps expression in the Drosophila melanogaster embryo
Abstract Proper development depends on precise spatiotemporal gene expression patterns. Most developmental genes are regulated by multiple enhancers and often by multiple core promoters that generate similar transcripts. We hypothesize that multiple promoters may be required either because enhancers prefer a specific promoter or because multiple promoters serve as a redundancy mechanism. To test these hypotheses, we studied the expression of the knirps locus in the early Drosophila melanogaster embryo, which is mediated by multiple enhancers and core promoters. We found that one of these promoters resembles a typical “sharp” developmental promoter, while the other resembles a “broad” promoter usually associated with housekeeping genes. Using synthetic reporter constructs, we found that some, but not all, enhancers in the locus show a preference for one promoter, indicating that promoters provide both redundancy and specificity. By analyzing the reporter dynamics, we identified specific burst properties during the transcription process, namely burst size and frequency, that are most strongly tuned by the combination of promoter and enhancer. Using locus-sized reporters, we discovered that enhancers with no promoter preference in a synthetic setting have a preference in the locus context. Our results suggest that the presence of multiple promoters in a locus is due both to enhancer preference and a need for redundancy and that “broad” promoters with dispersed transcription start sites are common among developmental genes. They also imply that it can be difficult to extrapolate expression measurements from synthetic reporters to the locus context, where other variables shape a gene’s overall expression pattern.
Li, Lily (ORCID:0000000301986521)↗
Embryo development and chick growth in a helium-oxygen atmosphere.
Avian embryo through hatching and chick growth in helium-oxygen atmosphere at one atmosphere and in sealed system
EMBRYOLOGY↗
Metabolism and x-ray sensitivity of chick embryos incubated in a helium-oxygen atmosphere.
Metabolic rate respiratory activity and X-ray sensitivity of chick embryos incubated in air or helium-oxygen atmosphere
RADIATION RESISTANCE↗
Embryo development and chick growth in a helium-oxygen atmosphere.
Embryo development and chick growth in helium-oxygen atmosphere
OXYGEN↗
Crystalline embryos at ice-vapor interfaces
The nucleation of small monolayer ice-like clusters at the basal and prism ice-vapor interfaces is considered. It is found that the basal surfaces prefer triangular embryos with an orientation that reverses from layer to layer, whereas the most stable clusters on the prism surfaces are rectangular in configuration. At any given saturation ratio, the preferred prism clusters are found to have a critical energy of formation significantly lower than that of the basal clusters, basically because of differences in cluster corner free energies.
Bartley, D. L.↗
Morphogenesis of a higher plant from cultured cells and embryos in space
Reference is made to the Cosmos 782 experiment, which showed that cultured totipotent cells of carrot can give rise to embryos with well-developed roots but minimally developed shoots at near-zero g. The problem of whether the development of leafy shoots is sensitive to near-zero g conditions is considered. A test system that would allow this problem to be resolved in a future space flight is described.
Krikorian, A. D.↗
Morphogenesis and calcification of the statoconia in the chick (Gallus domesticus) embryo - Implications for future studies
The morphogenesis of the statoconia in the chick, Gallus domesticus, injected with a carbon anhydrase inhibitor is studied. The preparation of the embryo specimens for analysis is described. The early, middle, and late stages of embryonic development are examined. The data reveal that acetozolamide inhibits statoconia formation in the middle stage of development and the calcification process follows statoconia formation. The spatial relationship between the development of type 1 and type 2 hair cells and the appearance and maturation of the statoconia is investigated.
Fermin, C. D.↗
Immunofluorescence localization of dissociation supernatant and extracellular matrix components in Lytechinus pictus sectioned embryos
Indirect immunofluorescence was used to localize specific extracellular components in embryos of the sea urchin Lytechinus pictus. Hyalin and S2 (a group of components found in the disaggregation supernatant from Strongylocentrotus purpuratus blastulae) were uniformly present at all stages (unfertilized up to 32 hr) except hyalin could not be detected at the 12 hour early blastula stage. Laminin was found in 16 cell, 32 cell, 6 hour, 18 hour, 24 hour, and 32 hour stages, with especially bright fluorescence at 18 hours. Collagen I was present at all stages (freshly fertilized up to 32 hour) except little was detected at 12 hours. Fibronectin was uniformly present in blastocoelar fibers stained with anto-collagen I and anti-fibronectin. These results were compared with those for S. purpuratus to produce an overview of the localization of specific extracellular matrix components during development of two species of sea urchins. The results set the stage for future studies that will examine the function of these components at the various developmental stages.
Garciaflack, Ana Leticia↗