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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Automated, Miniaturized Instrument for Measuring Gene Expression in Space

To facilitate astrobiological studies on the survival and adaptation of microorganisms and mixed microbial cultures to space environment, we have been developing a fully automated, miniaturized system for measuring their gene expression on small spacecraft. This low-cost, multi-purpose instrument represents a major scientific and technological advancement in our ability to study the impact of the space environment on biological systems by providing data on cellular metabolism and regulation orders of magnitude richer than what is currently available. The system supports growth of the organism, lyse it to release the expressed RNA, label the RNA, read the expression levels of a large number of genes by microarray analysis of labeled RNA and transmit the measurements to Earth. To measure gene expression we use microarray technology developed by CombiMatrix, which is based on electrochemical reactions on arrays of electrodes on a semiconductor substrate. Since the electrical integrity of the microarray remains intact after probe synthesis, the circuitry can be employed to sense nucleic acid binding at each electrode. CombiMatrix arrays can be sectored to allow multiple samples per chip. In addition, a single array can be used for several assays. The array has been integrated into an automated microfluidic cartridge that uses flexible reagent blisters and pinch pumping to move liquid reagents between chambers. The proposed instrument will help to understand adaptation of terrestrial life to conditions beyond the planet of origin, identify deleterious effects of the space environment, develop effective countermeasures against these effects, and test our ability to sustain and grow in space organisms that can be used for life support and in situ resource utilization during long-duration space exploration. The instrument is suitable for small satellite platforms, which provide frequent, low cost access to space. It can be also used on any other platform in space, including the ISS. It can be replicated and used with only small modifications in multiple biological experiments with a broad range of goals in mind.

Pohorille, A.↗
NASA NTRS2014

Global Gene Expression Profiling in Lung Tissues of Rat Exposed to Lunar Dust Particles

The Moon's surface is covered by a layer of fine, potential reactive dust. Lunar dust contain about 1‐2% respirable very fine dust (less than 3 micrometers). The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to analyze the dynamics of global gene expression changes in lung tissues of rats exposed to lunar dust particles. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose‐only inhalation chambers to concentrations of 0 (control air), 2.1, 6.8, 21, and 61 mg/m3 of lunar dust. Animals were euthanized at 1 day and 13 weeks after the last inhalation exposure. After being lavaged, lung tissue from each animal was collected and total RNA was isolated. Four samples of each dose group were analyzed using Agilent Rat GE v3 microarray to profile global gene expression of 44K transcripts. After background subtraction, normalization, and log transformation, t tests were used to compare the mean expression levels of each exposed group to the control group. Correction for multiple testing was made using the method of Benjamini, Krieger, and Yekuteli (1) to control the false discovery rate. Genes with significant changes of at least 1.75 fold were identified as genes of interest. Both low and high doses of lunar dust caused dramatic, dose‐dependent global gene expression changes in the lung tissues. However, the responses of lung tissue to low dose lunar dust are distinguished from those of high doses, especially those associated with 61mg/m3 dust exposure. The data were further integrated into the Ingenuity system to analyze the gene ontology (GO), pathway distribution and putative upstream regulators and gene targets. Multiple pathways, functions, and upstream regulators have been identified in response to lunar dust induced damage in the lung tissue.

Yeshitla, Samrawit A.↗
NASA NTRS2016

Network Security via Biometric Recognition of Patterns of Gene Expression

Molecular biology provides the ability to implement forms of information and network security completely outside the bounds of legacy security protocols and algorithms. This paper addresses an approach which instantiates the power of gene expression for security. Molecular biology provides a rich source of gene expression and regulation mechanisms, which can be adopted to use in the information and electronic communication domains. Conventional security protocols are becoming increasingly vulnerable due to more intensive, highly capable attacks on the underlying mathematics of cryptography. Security protocols are being undermined by social engineering and substandard implementations by IT organizations. Molecular biology can provide countermeasures to these weak points with the current security approaches. Future advances in instruments for analyzing assays will also enable this protocol to advance from one of cryptographic algorithms to an integrated system of cryptographic algorithms and real-time expression and assay of gene expression products.

cybersecurity↗
NASA NTRS2017

Simple Analytical Expressions for Electron Pitch Angle Diffusion Coefficients

In the present paper, we have calculated electron pitch angle diffusion coefficients due to resonant interactions with whistler mode lower band chorus (LBC), upper band chorus (UBC), and electrostatic electron cyclotron harmonic (ECH) waves. Calculations have been performed at two values of the ratio of electron plasma frequency to gyro-frequency and thirteen representative values of electron energies for the plasma sheet electrons. The numerical data of diffusion coefficients have been fitted to simple analytical expressions for each wave mode. These analytical expressions allow for simple evaluation of pitch angle diffusion coefficients for the arbitrary pitch angle, energy, the ambient magnetic field, the wave amplitude, and the ratio of plasma frequency to gyro-frequency. In the case of LBC waves, the analytical coefficients are generally within a factor of two to the numerical coefficients, except at higher pitch angles where the numerical coefficients drop to show negligible values. Likewise, also for UBC waves, the analytical coefficients are generally within a factor of two to the numerical coefficients. The analytical coefficients for ECH waves are generally in agreement with numerical coefficients. However, the analytical expressions developed for ECH waves do not reproduce sharp fluctuations, dips, and gaps, the so-called banded structure observed in the data of numerical coefficients. The effect of the shape variation on the profile of the wave spectral intensity and the effect of cold temperature on the numerical coefficients are also investigated. Applications of the analytical expressions of diffusion coefficients are discussed.

coefficients↗
NASA NTRS2016

Unpredictable Variable Prenatal Stress Programs Expression of Genes Involved in Appetite Control and Energy Expenditure

Exposure to stress in the womb shapes neurobiological and physiological outcomes of offspring in later life, including body weight regulation and metabolic profiles. Our previous work utilizing a centrifugation-induced hypergravity demonstrated significantly increased (8-15) body mass in male, but not female, rats exposed throughout gestation to chronic 2-g from conception to birth. We reported the same outcome in adult offspring exposed throughout gestation to Unpredictable Variable Prenatal Stress (UVPS). Here we examine gene expression changes using our UVPS model to identify a potential role for prenatal stress in this hypergravity programming effect. Specifically we focused on appetite control and energy expenditure pathways in prenatally stressed adult (90-day-old) male Sprague-Dawley rats. Time-mated female rats were exposed throughout their 22-day pregnancy to UVPS consisting of white noise, strobe light, and tube restraint individually once per day on an unpredictable schedule for 15, 30 or 60 min. To control for potential changes in postnatal maternal care, newborn pups were fostered to non-manipulated, newly parturient dams. At 90-days of age, we analyzed plasma concentrations of hormones involved in appetite control and energy expenditure (leptin and adiponectin), and quantified expression of key genes in epididymal fat pads harvested from adult male offspring and controls. Leptin regulates energy balance by inhibiting hunger, and adiponectin modulates glucose levels and fatty acid breakdown. Our findings indicate significantly elevated plasma leptin concentrations and reduced expression of epididymal fat leptin (OB) and adiponectin (ADIPOQ) genes compared to controls. Analyses presently underway include quantification of plasma insulin and glucose, and the expression of ghrelin, a peptide that acts on the central nervous system and the body's perception of hunger. Collectively, these findings will further understanding of the consequences of UVPS on body weight regulation and metabolism, and provide further insight into the effect of gravity modulation on mammalian fetal development.

Appetite Control↗
NASA NTRS2021

Anaerobic Expression and Purification of Holo-CCIS, an Artificial Iron-sulfur Protein

Iron-sulfur proteins are ubiquitous among all living organisms and are indispensable for almost all metabolic pathways ranging from photosynthesis, respiration, nitrogen, and carbon dioxide cycles. The iron-sulfur clusters primarily serve as electron acceptors and donors and transfer electrons to active sites of various enzymes, thus driving the energy metabolism. Prokaryotes like E. coli have ISC and SUF pathways that help in the assembly and maturation of iron-sulfur proteins. These ironsulfur proteins, especially with [4Fe-4S] clusters, are highly sensitive to molecular oxygen, and it would be advantageous if the de novo proteins and native proteins having iron-sulfur binding sites are expressed and isolated under anaerobic conditions. Bacterially assembled iron-sulfur proteins, when isolated and purified anaerobically, exhibit improved biochemical and biophysical stabilities in comparison to the counterparts expressed and purified aerobically and reconstituted under anaerobic conditions. This protocol outlines the expression and purification of the artificial protein, Coiled-Coil IronSulfur (CCIS). It may be deployed to both natural and artificial [4Fe-4S] proteins when heterologously expressed in E. coli.

Bhanu P. Jagilinki↗
NASA NTRS2002

Patterns of gene expression in atrophying skeletal muscles: response to food deprivation

During fasting and many systemic diseases, muscle undergoes rapid loss of protein and functional capacity. To define the transcriptional changes triggering muscle atrophy and energy conservation in fasting, we used cDNA microarrays to compare mRNAs from muscles of control and food-deprived mice. Expression of >94% of genes did not change, but interesting patterns emerged among genes that were differentially expressed: 1) mRNAs encoding polyubiquitin, ubiquitin extension proteins, and many (but not all) proteasome subunits increased, which presumably contributes to accelerated protein breakdown; 2) a dramatic increase in mRNA for the ubiquitin ligase, atrogin-1, but not most E3s; 3) a significant suppression of mRNA for myosin binding protein H (but not other myofibrillar proteins) and IGF binding protein 5, which may favor cell protein loss; 4) decreases in mRNAs for several glycolytic enzymes and phosphorylase kinase subunits, and dramatic increases in mRNAs for pyruvate dehydrogenase kinase 4 and glutamine synthase, which should promote glucose sparing and gluconeogenesis. During fasting, metallothionein mRNA increased dramatically, mRNAs for extracellular matrix components fell, and mRNAs that may favor cap-independent mRNA translation rose. Significant changes occurred in mRNAs for many growth-related proteins and transcriptional regulators. These transcriptional changes indicate a complex adaptive program that should favor protein degradation and suppress glucose oxidation in muscle. Similar analysis of muscles atrophying for other causes is allowing us to identify a set of atrophy-specific changes in gene expression.

Non-NASA Center↗
NASA NTRS2003

The expression and function of the achaete-scute genes in Tribolium castaneum reveals conservation and variation in neural pattern formation and cell fate specification

The study of achaete-scute (ac/sc) genes has recently become a paradigm to understand the evolution and development of the arthropod nervous system. We describe the identification and characterization of the ac/sc genes in the coleopteran insect species Tribolium castaneum. We have identified two Tribolium ac/sc genes - achaete-scute homolog (Tc-ASH) a proneural gene and asense (Tc-ase) a neural precursor gene that reside in a gene complex. Focusing on the embryonic central nervous system we find that Tc-ASH is expressed in all neural precursors and the proneural clusters from which they segregate. Through RNAi and misexpression studies we show that Tc-ASH is necessary for neural precursor formation in Tribolium and sufficient for neural precursor formation in Drosophila. Comparison of the function of the Drosophila and Tribolium proneural ac/sc genes suggests that in the Drosophila lineage these genes have maintained their ancestral function in neural precursor formation and have acquired a new role in the fate specification of individual neural precursors. Furthermore, we find that Tc-ase is expressed in all neural precursors suggesting an important and conserved role for asense genes in insect nervous system development. Our analysis of the Tribolium ac/sc genes indicates significant plasticity in gene number, expression and function, and implicates these modifications in the evolution of arthropod neural development.

Non-NASA Center↗
NASA NTRS2003

Expression and function of FGF10 in mammalian inner ear development

We have investigated the expression of FGF10 during ear development and the effect of an FGF10 null mutation on ear development. Our in situ hybridization data reveal expression of FGF10 in all three canal crista sensory epithelia and the cochlea anlage as well as all sensory neurons at embryonic day 11.5 (E11.5). Older embryos (E18.5) displayed strong graded expression in all sensory epithelia. FGF10 null mutants show complete agenesis of the posterior canal crista and the posterior canal. The posterior canal sensory neurons form initially and project rather normally by E11.5, but they disappear within 2 days. FGF10 null mutants have no posterior canal system at E18.5. In addition, these mutants have deformations of the anterior and horizontal cristae, reduced formation of the anterior and horizontal canals, as well as altered position of the remaining sensory epithelia with respect to the utricle. Hair cells form but some have defects in their cilia formation. No defects were detected in the organ of Corti at the cellular level. Together these data suggest that FGF10 plays a major role in ear morphogenesis. Most of these data are consistent with earlier findings on a null mutation in FGFR2b, one of FGF10's main receptors. Copyright 2003 Wiley-Liss, Inc.

NASA Discipline Developmental Biology↗
NASA NTRS2002

Computational Model of the Modulation of Gene Expression Following DNA Damage

High linear energy transfer (LET) radiation, such as heavy ions or neutrons, has an increased biological effectiveness compared to X rays for gene mutation, genomic instability, and carcinogenesis. In the traditional paradigm, mutations or chromosomal aberrations are causative of late effects. However, in recent years experimental evidence has demonstrated the important role of the description of the modification of gene expression by radiation in understanding the mechanisms of radiation action. In this report, approaches are discussed to the mathematical description of mRNA and protein expression kinetics following DNA damage. Several hypotheses for models of radiation modulation of protein expression are discussed including possible non-linear processes that evolve from the linear dose responses that follow the initial DNA damage produced by radiation.

NASA Center JSC↗
NASA NTRS2002

Differential effects of intermittent and continuous administration of parathyroid hormone on bone histomorphometry and gene expression

A mechanism explaining the differential skeletal effects of intermittent and continuous elevation of serum parathyroid hormone (PTH) remains elusive. Intermittent PTH increases bone formation and bone mass and is being investigated as a therapy for osteoporosis. By contrast, chronic hyperparathyroidism results in the metabolic bone disease osteitis fibrosa characterized by osteomalacia, focal bone resorption, and peritrabecular bone marrow fibrosis. Intermittent and continuous PTH have similar effects on the number of osteoblasts and bone-forming activity. Many of the beneficial as well as detrimental effects of the hormone appear to be mediated by osteoblast-derived growth factors. This hypothesis was tested using cDNA microgene arrays to compare gene expression in tibia of rats treated with continuous and pulsatile administration of PTH. These treatments result in differential expression of many genes, including growth factors. One of the genes whose steady-state mRNA levels was increased by continuous but not pulsatile administration was platelet-derived growth factor-A (PDGF-A). Administration of a PDGF-A antagonist greatly reduced bone resorption, osteomalacia, and bone marrow fibrosis in a rat model for hyperparathyroidism, suggesting that PDGF-A is a causative agent for this disease. These findings suggest that profiling changes in gene expression can help identify the metabolic pathways responsible for the skeletal responses to the hormone.

Review↗
NASA NTRS1996

Expression of spicule matrix protein gene SM30 in embryonic and adult mineralized tissues of sea urchin Hemicentrotus pulcherrimus

We have isolated a cDNA clone for spicule matrix protein, SM30, from sea urchin Hemicentrotus pulcherrimus and have studied the expression of this gene in comparison with that of another spicule matrix protein gene, SM50. In cultured micromeres as well as in intact embryos transcripts of SM30 were first detectable around the onset of spicule formation and rapidly increased with the growth of spicules, which accompanied accumulation of glycosylated SM30 protein(s). When micromeres were cultured in the presence of Zn2+, spicule formation and SM30 expression were suppressed, while both events resumed concurrently after the removal of Zn2+ from the culture medium. Expression of SM50, in contrast, started before the appearance of spicules and was not sensitive to Zn2+. Differences were also observed in adult tissues; SM30 mRNA was detected in spines and tube feet but not in the test, while SM50 mRNA was apparent in all of these mineralized tissues at similar levels. These results strongly suggest that the SM30 gene is regulated by a different mechanism to that of the SM50 gene and that the products of these two genes are differently involved in sea urchin biomineralization. A possible role of SM30 protein in skeleton formation is discussed.

NASA Discipline Musculoskeletal↗
NASA NTRS1994

Prostanoid-induced expression of matrix metalloproteinase-1 messenger ribonucleic acid in rat osteosarcoma cells

Individual prostanoids have distinct potencies in activating intracellular signaling pathways and regulating gene expression in osteoblastic cells. The E-series prostaglandins (PGs) are known to stimulate matrix metalloproteinase-1 (MMP-1) synthesis and secretion in certain rodent and human osteoblastic cells, yet the intracellular events involved remain unclear. To further characterize this response and its signal transduction pathway(s), we examined prostanoid-induced expression of the MMP-1 gene in the rat osteoblastic osteosarcoma cell line UMR 106-01. Northern blot analysis demonstrated that prostaglandin E2 (PGE2) and PGE1 were very potent stimulators (40-fold) of MMP-1 transcript abundance, PGF2 alpha and prostacyclin were weak stimulators (4-fold), and thromboxane-B2 had no effect. The marked increase in MMP-1 transcript abundance after PGE2 treatment was first detected at 2 h, became maximal at 4 h, and persisted beyond 24 h. This response was dose dependent and elicited maximal and half-maximal effects with concentrations of 10(-6) and 0.6 x 10(-7) M, respectively. Cycloheximide, a protein synthesis inhibitor, completely blocked this effect of PGE2, suggesting that the expression of other genes is required. Nuclear run-on experiments demonstrated that PGE2 rapidly activates MMP-1 gene transcription, with a maximal increase at 2-4 h. The second messenger analog, 8-bromo-cAMP, mimicked the effects of PGE2 by stimulating a dose-dependent increase in MMP-1 messenger RNA (mRNA) levels, with a maximal effect quantitatively similar to that observed with PGE2. Thus, in UMR 106-01 cells, different prostanoids have distinct potencies in stimulating MMP-1 mRNA abundance. Our data suggest that PGE2 stimulation of MMP-1 synthesis is due to activation of MMP-1 gene transcription and a subsequent marked increase in MMP-1 mRNA abundance. This effect is dependent on de novo protein synthesis and is mimicked by protein kinase-A activation.

NASA Discipline Musculoskeletal↗
NASA NTRS1993

HSP86 and HSP84 exhibit cellular specificity of expression and co-precipitate with an HSP70 family member in the murine testis

This study extends to the protein level our previous observations, which had established the stage and cellular specificity of expression of hsp86 and hsp84 in the murine testis in the absence of exogenous stress. Immunoblot analysis was used to demonstrate that HSP86 protein was present throughout testicular development and that its levels increased with the appearance of differentiating germ cells. HSP86 was most abundant in the germ cell population and was present at significantly lower levels in the somatic cells. By contrast, the HSP84 protein was detected in the somatic cells of the testis rather than in germ cells. The steady-state levels of HSP86 and HSP84 paralleled the pattern of the expression of their respective mRNAs, suggesting that regulation at the level of translation was not a major mechanism controlling hsp90 gene expression in testicular cells. Immunoprecipitation analysis revealed that a 70-kDa protein coprecipitated with the HSP86/HSP84 proteins in testicular homogenates. This protein was identified as an HSP70 family member by immunoblot analysis, suggesting that HSP70 and HSP90 family members interact in testicular cells.

NASA Discipline Number 40-20↗
NASA NTRS1992

Changes in skeletal muscle gene expression consequent to altered weight bearing

Skeletal muscle is a dynamic organ that adapts to alterations in weight bearing. This brief review examines changes in muscle gene expression resulting from the removal of weight bearing by hindlimb suspension and from increased weight bearing due to eccentric exercise. Acute (less than or equal to 2 days) non-weight bearing of adult rat soleus muscle alters only the translational control of muscle gene expression, while chronic (greater than or equal to 7 days) removal of weight bearing appears to influence pretranslational, translational, and posttranslational mechanisms of control. Acute and chronic eccentric exercise are associated with alterations of translational and posttranslational control, while chronic eccentric training also alters the pretranslational control of muscle gene expression. Thus alterations in weight bearing influence multiple sites of gene regulation.

NASA Discipline Musculoskeletal↗
NASA NTRS2004

Modeled microgravity-induced protein kinase C isoform expression in human lymphocytes

In long-term space travel, the crew is exposed to microgravity and radiation that invoke potential hazards to the immune system. T cell activation is a critical step in the immune response. Receptor-mediated signaling is inhibited in both microgravity and modeled microgravity (MMG) as reflected by diminished DNA synthesis in peripheral blood lymphocytes and their locomotion through gelled type I collagen. Direct activation of protein kinase C (PKC) bypassing cell surface events using the phorbol ester PMA rescues MMG-inhibited lymphocyte activation and locomotion, whereas the calcium ionophore ionomycin had no rescue effect. Thus calcium-independent PKC isoforms may be affected in MMG-induced locomotion inhibition and rescue. Both calcium-dependent isoforms and calcium-independent PKC isoforms were investigated to assess their expression in lymphocytes in 1 g and MMG culture. Human lymphocytes were cultured and harvested at 24, 48, 72, and 96 h, and serial samples were assessed for locomotion by using type I collagen and expression of PKC isoforms. Expression of PKC-alpha, -delta, and -epsilon was assessed by RT-PCR, flow cytometry, and immunoblotting. Results indicated that PKC isoforms delta and epsilon were downregulated by >50% at the transcriptional and translational levels in MMG-cultured lymphocytes compared with 1-g controls. Events upstream of PKC, such as phosphorylation of phospholipase Cgamma in MMG, revealed accumulation of inactive enzyme. Depressed calcium-independent PKC isoforms may be a consequence of an upstream lesion in the signal transduction pathway. The differential response among calcium-dependent and calcium-independent isoforms may actually result from MMG intrusion events earlier than PKC, but after ligand-receptor interaction.

Lymphocytes/enzymology↗
NASA NTRS2001

Mars Express: exploration of Phobos

The ESA Mars Express Orbiter will be nearly polar and have an initial orbital period of 7.6 hours for the first 440 days and then will reduce its period to 6.7 hours. As periapsis of the elliptical orbit walks around Mars every 2 years, the ascending and descending nodes of the Mars Express orbit on the Mars equatorial plane will have the same radius as the orbit of Phobos and close encounters of Phobos will occur when Phobos is near the node as Mars Express passes.

Mars Express exploration of Phobos↗
NASA NTRS2001

Mars Express: exploration of Phobos

The ESA Mars Express Orbiter will be nearly polar and have an initial orbital period of 7.6 hours for the first 440 days and then will reduce its period to 6.7 hours. As periapsis of the elliptical orbit walks around Mars every 2 years, the ascending and descending nodes of the Mars Express orbit on the Mars equatorial plane will have the same radius as the orbit of Phobos and close encounters of Phobos will occur when Phobos is near the node as Mars Express passes.

Mars Express exploration of Phobos↗