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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Bovine eggs release zinc in response to parthenogenetic and sperm-induced egg activation

Upon fertilization or parthenogenesis, zinc is released into the extracellular space through a series of exocytic events termed zinc sparks, which are tightly coordinated with intracellular calcium transients. The zinc spark reduces the total amount of intracellular zinc, and this reduction is necessary and sufficient to induce egg activation even in the absence of calcium transients. In addition, this zinc release contributes to the block to polyspermy through modification of the zona pellucida. The zinc spark has been documented in all organisms examined to date including the mouse, two species of nonhuman primates, and human. Here we determined whether zinc sparks occur in the bovine, an important model of gamete development in mono-ovulatory mammalian species. We obtained metaphase II-arrested (MII) bovine eggs following in vitro maturation. Total zinc, assessed in single cells using X-Ray Fluorescence Microscopy, was significantly more abundant in the bovine egg compared to iron and copper. Studies with intracellular fluorescent probes revealed that labile zinc pools are localized to discrete cytoplasmic punctae enriched at the cortex. To determine whether zinc undergoes dynamic fluxes during egg activation, we parthenogenetically activated bovine eggs using two approaches: ionomycin or bovine phospholipase C zeta (b Plc ζ) Both these methods induced zinc sparks coordinately with intracellular calcium transients. The zinc spark was also observed in bovine eggs following intracytoplasmic sperm injection. Furthermore, these results establish that zinc is the most abundant transition metal in the bovine egg, and zinc flux during egg activation-induced by chemical activation or sperm-is a highly conserved event across mammalian species.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Free-moving artificial eggs containing temperature loggers reveal remarkable within-clutch variance in incubation temperature

Incubation is a crucial aspect of avian parental care and measuring incubation temperature in the wild can improve our understanding of life history tradeoffs and inform conservation efforts. However, there are challenges associated with measuring the temperature of eggs in natural nests. Most studies to date have measured incubation temperature by using a single, stationary logger in each nest. However, real eggs are rotated and moved throughout the nest by the parent during the incubation period, and thus, a stationary logger may not accurately represent the temperature experienced by individual eggs within the entire clutch. We recorded incubation temperature in nests by using multiple, mobile artificial egg temperature loggers. We installed six mobile loggers and one stationary logger in wood duck Aix sponsa nests to compare the two logger types in the field. We found that at a given ambient temperature, mobile loggers recorded lower average and more variable temperatures than stationary loggers. Further, temperatures recorded by stationary loggers showed no relationship with clutch size, while mobile loggers captured temperatures that were lower and more variable as clutch size increased. Also, the multiple mobile loggers revealed that eggs within a nest experienced a substantial range of temperatures throughout the incubation period. Here, we discuss potential limitations of this method, but believe that it is a promising way to collect biologically-relevant incubation temperature data and provides an opportunity to advance our understanding of incubation temperature as a parental effect.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Lead exposure to children from consumption of backyard chicken eggs

Highlights: • Backyard chicken eggs from most households providing egg samples (98%) contained detectable concentrations of lead. • IIn prediction models, backyard egg consumption increased overall blood lead levels in children • Infants < 1 year of age experience the greatest increase in predicted blood lead levels from backyard egg consumption. • Mean household egg lead concentration was strongly positively correlated with coop soil lead concentrations. Backyard chicken ownership is rapidly increasing in urban areas in the United States, largely as a way to provide eggs for household consumption. Despite elevated levels of environmental lead contamination in many US cities, the role of backyard chicken eggs as a pathway for lead exposure, particularly for children, has received limited scrutiny. To characterize lead exposure from consumption of backyard chicken eggs for children and predict related effects on blood lead level (BLL), we conducted a cross-sectional study of backyard chicken owners in the Greater Boston area (n = 51). We interviewed participants regarding egg consumption by household members and collected backyard eggs (n = 201) and coop soil samples (n = 48) for analysis. Inductively coupled plasma mass spectrometry (ICP-MS) was used to evaluate lead concentration in homogenized eggs and an X-ray fluorescence (XRF) portable device was used to assess soil lead levels in the laboratory. We used the USEPA's Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK) to assess the relative contribution of backyard egg consumption to aggregate BLL in children. Four scenarios were developed in the IEUBK model to address variability in egg consumption rates and egg lead contamination. Lead was detected in egg samples from 98% of the households that provided egg samples. Mean household lead concentration was 0.10 μg/g (SD: 0.18). Egg lead concentrations ranged from below the limit of detection (0.0014 μg/g) to 1.798 μg/g (<1.4–1198 ppb). Egg lead levels were strongly positively correlated with lead concentration in coop soil (r = 0.64; p < 0.001). In modeled scenarios where a child < 7 years frequently ate eggs highly contaminated with lead, BLLs are predicted to increase by 0.9–1.5 μg/dL. In three other scenarios reflecting more moderate egg lead contamination and consumption rates, BLLs were predicted to increase from 0.1 to 0.8 μg/dL. Consumption of backyard chicken eggs can contribute to lead exposure in children. Soil lead remediation prior to chicken ownership may reduce lead exposure from backyard eggs.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

D-Egg: a dual PMT optical module for IceCube

The D-Egg, an acronym for "Dual optical sensors in an Ellipsoid Glass for Gen2," is one of the optical modules designed for future extensions of the IceCube experiment at the South Pole. The D-Egg has an elongated-sphere shape to maximize the photon-sensitive effective area while maintaining a narrow diameter to reduce the cost and the time needed for drilling of the deployment holes in the glacial ice for the optical modules at depths up to 2700 m. The D-Egg design is utilized for the IceCube Upgrade, the next stage of the IceCube project also known as IceCube-Gen2 Phase 1, where nearly half of the optical sensors to be deployed are D-Eggs. With two 8-inch high-quantum efficiency photomultiplier tubes (PMTs) per module, D-Eggs offer an increased effective area while retaining the successful design of the IceCube digital optical module (DOM). The convolution of the wavelength-dependent effective area and the Cherenkov emission spectrum provides an effective photodetection sensitivity that is 2.8 times larger than that of IceCube DOMs. The signal of each of the two PMTs is digitized using ultra-low-power 14-bit analog-to-digital converters with a sampling frequency of 240 MSPS, enabling a flexible event triggering, as well as seamless and lossless event recording of single-photon signals to multi-photons exceeding 200 photoelectrons within 10 ns. Mass production of D-Eggs has been completed, with 277 out of the 310 D-Eggs produced to be used in the IceCube Upgrade. In this paper, we report the design of the D-Eggs, as well as the sensitivity and the single to multi-photon detection performance of mass-produced D-Eggs measured in a laboratory using the built-in data acquisition system in each D-Egg optical sensor module.

47 OTHER INSTRUMENTATION↗
DOE OSTI2019

Supplemental defatted microalgae affects egg and tissue fatty acid composition differently in laying hens fed diets containing corn and flaxseed oil

Effects of defatted microalgae (DFA) on fatty acid composition of eggs and tissues of hens have not been well studied. This experiment was to determine how low concentrations of supplemental DFA in the presence or absence of flaxseed oil (FO) altered fatty acid profiles of egg yolk, liver, adipose tissue, and plasma of layers. A total of 60 Shaver Leghorn layer hens (individually caged, 20-wk old) were allotted into 6 groups (n = 10) and fed a corn/soybean meal basal diet containing 0, 3, or 5% DFA and 0 (1.5% corn oil, CO) or 1.5% FO for 6 wk. BW, ADFI, egg production rate, and egg component weights were not affected by any of the dietary treatments at various time points, but egg yolk color was changed (P < 0.05) with increasing concentrations of DFA. The concentration of n-3 fatty acids in egg yolk and plasma were elevated by FO up to 9-fold (P < 0.05) starting at wk 1 or 2, and 39 to 83% (P < 0.05) by DFA. Supplemental DFA improved (P < 0.05) n-6/n-3 fatty acid ratios in egg yolk and plasma from 13 to 23 and 7 to 13, respectively, only in hens fed diets without FO. Fatty acid profiles of liver and adipose tissue (at wk 6) displayed responses to supplemental DFA and FO similar to those of egg yolk or plasma. In conclusion, supplemental 3 or 5% DFA caused moderate enrichments of n-3 fatty acids and decreased the n6/n3 fatty acid ratios of egg yolk and tissues in hens fed diets without FO.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1994

Provisional bilateral symmetry in Xenopus eggs is established during maturation

Dorsal-ventral patterning in the Xenopus egg becomes established midway through the first cell cycle during a 30 degree rotation of the subcortical yolk mass relative to the egg cortex. This 'rotation of symmetrisation' is microtubule dependent, and its direction is thought to be cued by the usually eccentric sperm centrosome. The fact that parthenogenetically activated eggs also undergo a directed rotation, despite the absence of a sperm centrosome, suggests that an endogenous asymmetry in the unfertilised egg supports the directed polymerisation of microtubules in the vegetal cortex, in the way that an eccentric sperm centrosome would in fertilised eggs. Consistent with this idea, we noticed that the maturation spot is usually located an average of more than 15 degrees from the geometric centre of the pigmented animal hemisphere. In parthenogenetically activated eggs, this eccentric maturation spot can be used to predict the direction of rotation. Although in most fertilised eggs the yolk mass rotates toward the sperm entry point (SEP) meridian, occasionally this relationship is perturbed significantly; in such eggs, the maturation spot is never on the same side of the egg as the SEP. In oocytes tilted 90 degrees from upright during maturation in vitro, the maturation spot developed 15 degrees or more from the centre of the pigmented hemisphere, always displaced towards the point on the equator that was up during maturation. This experimentally demonstrated lability is consistent with an off-axis oocyte orientation during oogenesis determining its eccentric maturation spot position, and, in turn, its endogenous rotational bias.

NASA Discipline Number 40-20↗
NASA NTRS1984

Cytoplasmic rearrangements associated with amphibian egg symmetrization

Cytoplasmic rearrangements which follow fertilization were mentioned in normal and inverted eggs. A set of yolk compartments was resolved by cytological analyses of both normally oriented and inverted eggs. Those compartments were characterized by their yolk platelet compositions and movement during egg inversion. It is found that during egg inversion the yolk compartments shift minor cytoplasmic compartments which line the egg cortex. Those yolk mass shifts occurred only after the inverted egg was activated. The direction of shift of the major yolk components, rather than the sperm entrance site, determines the dorsal/ventral polarity of the inverted egg. Among different spawnings the rate of shift varied. Eggs that displayed the fastest rate of shift exhibited the highest frequency of developmental abnormalities during organogenesis. Interpretation of novel observations on cytoplasmic organization provide criticism of some earlier models. A new density compartment model is presented as a coherent way to view the organization of the egg cytoplasm and the development of bilateral symmetry.

Malacinski, G. M.↗
NASA NTRS1992

Activation of maternal centrosomes in unfertilized sea urchin eggs

Centrosomes are undetectable in unfertilized sea urchin eggs, and normally the sperm introduces the cell's microtubule-organizing center (MTOC) at fertilization. However, artificial activation or parthenogenesis triggers microtubule assembly in the unfertilized egg, and this study explores the reappearance and behavior of the maternal centrosome. During activation with A23187 or ammonia, microtubules appear first at the cortex; centrosomal antigen is detected diffusely throughout the entire cytoplasm. Later, the centrosome becomes more distinct and organizes a radial microtubule shell, and eventually a compact centrosome at the egg center organizes a monaster. In these activated eggs, centrosomes undergo cycles of compaction and decompaction in synchrony with the chromatin, which also undergoes cycles of condensation and decondensation. Parthenogenetic activation with heavy water (50% D2O) or the microtubule-stabilizing drug taxol (10 microM) induces numerous centrosomal foci in the unfertilized sea urchin egg. Within 15 min after incubation in D2O, numerous fine centrosomal foci are detected, and they organize a connected network of numerous asters which fill the entire egg. Taxol induces over 100 centrosomal foci by 15 min after treatment, which organize a corresponding number of asters. The centrosomal material in either D2O- or taxol-treated eggs aggregates with time to form fewer but denser foci, resulting in fewer and larger asters. Fertilization of eggs pretreated with either D2O or taxol shows that the paternal centrosome is dominant over the maternal centrosome. The centrosomal material gradually becomes associated with the enlarged sperm aster. These experiments demonstrate that maternal centrosomal material is present in the unfertilized egg, likely as dispersed undetectable material, which can be activated without paternal contributions. At fertilization, paternal centrosomes become dominant over the maternal centrosomal material.

Non-NASA Center↗
DOE OSTI2022

Human sperm TMEM95 binds eggs and facilitates membrane fusion

Tmem95 encodes a sperm acrosomal membrane protein, whose knockout has a male-specific sterility phenotype in mice. Tmem95 knockout murine sperm can bind to, but do not fuse with, eggs. How TMEM95 plays a role in membrane fusion of sperm and eggs has remained elusive. Here, we utilize a sperm penetration assay as a model system to investigate the function of human TMEM95. We show that human TMEM95 binds to hamster egg membranes, providing evidence for a TMEM95 receptor on eggs. Using X-ray crystallography, we reveal an evolutionarily conserved, positively charged region of TMEM95 as a putative receptor-binding surface. Amino acid substitutions within this region of TMEM95 ablate egg-binding activity. We identify monoclonal antibodies against TMEM95 that reduce the number of human sperm fused with hamster eggs in sperm penetration assays. Strikingly, these antibodies do not block binding of sperm to eggs. Taken together, these results provide strong evidence for a specific, receptor-mediated interaction of sperm TMEM95 with eggs and suggest that this interaction may have a role in facilitating membrane fusion during fertilization.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Organic Chemical Concentrations in Eggs and Nestlings of Cavity Nesting Birds at and around Los Alamos National Laboratory

In 1943, Los Alamos National Laboratory (LANL) was established as part of the Manhattan project to design atomic weapons. LANL now operates as a multidisciplinary research institution. As part of an ongoing assessment of siterelated ecological risk, organochlorine pesticides, their metabolites, polycyclic aromatic hydrocarbons, polychlorinated biphenyls (PCBs), and 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were evaluated in western bluebird (Sialia mexicana) and ash-throated flycatcher (Myiarchus cinerascens) eggs relative to a developed but non-industrial reference area; PCBs and TEQs were also evaluated in nestlings. Chemicals were below detection limits in the majority of samples. Western bluebird eggs collected from the study area had significantly lower concentrations of dieldrin, oxychlordane, and trans-nonachlor when compared with eggs from the reference area. No differences were observed in concentrations of dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyltrichloroethane (DDT), and heptachlor epoxide. Ash-throated flycatcher eggs contained higher total TEQ concentrations when compared with western bluebird eggs; however, no differences in concentrations of DDE, DDT, dieldrin, or total PCBs were observed. No differences were observed in total PCBs or TEQs in nestlings between the two species. Western bluebird eggs contained higher levels of total PCBs and TEQs when compared with nestlings; no differences were observed in total PCBs or TEQs between ash-throated flycatcher eggs and nestlings. Chemical concentrations detected in eggs of both species were below levels that are associated with adverse effects reported in the scientific literature, suggesting that concentrations of organic chemicals observed here appear to be at levels causing negligible risks to local bird populations.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Microscopic diffusion in hydrated encysted eggs of brine shrimp

We have studied microscopic diffusion of water in fully hydrated encysted eggs of brine shrimp (Artemia). We utilized quasielastic neutron scattering. Dry eggs of brine shrimp were rehydrated using (1) water without additives, (2) eutectic mixture of water and dimethyl sulfoxide, and (3) a concentrated aqueous solution of lithium chloride. Despite the complexity of the hydrated multicellular organism, measurable microscopic diffusivity of water is rather well defined. Pure hydration water in eggs exhibits freezing temperature depression, whereas hydration water in eggs mixed with dimethyl sulfoxide or lithium chloride does not crystallize at all. The characteristic size of the voids occupied by water or aqueous solvents in hydrated brine shrimp eggs is between 2 and 10 nm. Those voids are accessible to co-solvents such as dimethyl sulfoxide and lithium chloride. There is no evidence of intracellular water in the hydrated eggs. The lack of intracellular water in the fully hydrated (but still under arrested development) state must be linked to the unique resilience against adverse environmental factors documented not only for the anhydrous, but also hydrated encysted eggs of brine shrimp.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Can acceptable quality angel food cakes be made using pasteurized shell eggs? The effects of mixing factors on functional properties of angel food cakes

Due to recent Salmonella outbreaks, the pasteurized shell egg market is rapidly growing. One objection to using pasteurized eggs is the belief that they will produce unacceptable angel food cakes. Eggs were pasteurized using a hot water immersion process (56.7°C for 60 min) similar to that used by industry. Angel food cakes were made from the pasteurized egg white (PEW) as well as from raw egg white (REW) for comparison. Meringues were made using three mixer speed settings (low, medium, and high) and three durations for each speed. Functional qualities such as egg foaming were evaluated. Angel food cakes were compared in terms of cake volume, texture profile, and color values. When the optimal processing factors used for REW were applied to PEW, an inferior meringue was formed. However, by increasing the mixing time for PEW by 200% at the highest speed, an acceptable meringue was formed. The best angel food cake prepared from PEW had a volume only 6.8% less than that of the best cake prepared from REW. Texture profile analyses showed that the best angel food cake made from PEW was 13% firmer, 7.4% less springy, and 62% chewier than that from REW. Color analyses showed that PEW made a slightly darker colored cake crust than REW, although there were no significant differences in the crumb color. Modifying the mixing conditions for PEW resulted in angel food cakes with quality similar to that of cakes made with REW, thus overcoming an objection to using safer pasteurized shell eggs.

Food Science & Technology↗
DOE OSTI2018

Inorganic Elements in Eggs of Two Cavity-Nesting Passerine Species at and around Los Alamos National Laboratory, Los Alamos, New Mexico

Los Alamos National Laboratory (LANL) was established in 1943 as part of the Manhattan Project to build nuclear weapons, and currently operates as a national research laboratory. As part of an ongoing assessment of site-related ecological risk at LANL, western bluebird (Sialia mexicana) and ash-throated flycatcher (Myiarchus cinerascens) eggs were collected from 1997 to 2012 and analyzed for 18 inorganic elements. Concentrations of many inorganic elements in eggs were below reporting limits. Between species comparisons revealed that western bluebird eggs had higher levels of barium while ash-throated flycatcher eggs had higher levels of mercury. No statistically significant differences were observed in concentrations of inorganic elements in western bluebird eggs collected from the study area (which consists of areas within the current and historic LANL boundary) and from a non-industrial reference site; nor were any statistically significant differences observed between two canyons of interest, known to have received effluents and storm water runoff from LANL facilities, and the non-industrial reference site. Inorganic element levels detected in western bluebirds were typically within the range measured in eggs of other passerine in the published literature. Furthermore, these data suggest that concentrations of inorganic elements in passerine eggs collected from the study area appear to be at levels causing negligible risks to local bird populations.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1992

Understanding the organization of the amphibian egg cytoplasm - Gravitational force as a probe

A combination of hypergravity (centrifugation) and hypogravity (clinostat) studies have been carried out on amphibian (frog, Xenopus) eggs. The results reveal that the twinning caused by centrifugation exhibits substantial spawning to spawning variation. That variation can be attributed to the apparent viscosity of the egg's internal cytoplasm. Simulated hypogravity results in a relocation of the egg's third (horizontal) cleavage furrow, toward the equator. Substantial egg-to-egg variation is also observed in this 'cleavage effect'. For interpreting spaceflight data and for using G-forces as probes for understanding the egg's architecture the egg variation documented herein should be considered.

Neff, Anton W.↗
NASA NTRS1984

Delayed fertilization of anuran amphibian (Xenopus) eggs leads to reduced numbers of primordial germ cells

Several media were tested for the extent to which they promoted high fertilization efficiencies in ovulated, stripped Xenopus eggs. One medium was selected for maintaining eggs in a 'delayed fertilization' (DelF) condition. DelF eggs displayed several unusual characteristics, including shift of the center of gravity, prominent sperm entrance site, and occasional polyspermy. The frequency of normal pattern formation varied according to the length of time eggs were maintained in the DelF condition. Various developmental abnormalities were observed during gastrulation, neurulation, and organogenesis. Most abnormalities appeared, however, to be related to morphogenesis of the endoderm. Primordial germ cell (PGC) development was examined in DelF eggs which displayed normal external morphological features at the swimming tadpole stage. PGC counts were usually normal in short-duration (eg, 5 hr) DelF eggs, but frequently substantially reduced or completely diminished in longer-duration (eg, 25h) tadpoles. Six spawnings were compared and shown to exhibit considerable variability in fertility, morphogenesis, and PGC development. Yolk platelet shifts and developmental parameters were examined in two additional spawnings. The subcortical cytoplasm in which the germ plasm is normally localized appeared to be disrupted in longer duration DelF eggs. That observation may account for low PGC counts in DelF tadpoles.

NASA Discipline Number 40-20↗