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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Organic analysis of the Antarctic carbonaceous chondrites

Thus far, organic analysis of carbonaceous chondrites has proven the only fruitful means of examining complex organic matter of extraterrestrial origin. The present paper presents the results of organic analysis of two Antarctic meteorites, Allan Hills (77306) and Yamato (74662), which may be considered free from terrestrial contamination. Ion-exchange chromatography, gas chromatography and mass spectrometery of meteorite samples reveal the presence in Yamato of 15 and in Allan Hills of 20 protein and nonprotein amino acids, the most abundant of which are glycine and alanine. Abundances of the D and L enantiomers of each amino acid are also found to be nearly equal. Data thus indicate an abiotic extraterrestrial origin for the matter, and confirm a lack of terrestrial contamination.

Kotra, R. K.↗
NASA NTRS1981

Possible selective adsorption of enantiomers by Na-montmorillonite

Racemic amino acids including (D,L) alpha-alamine, (D,L) alpha-aminobutyric acid, (D,L) valine, and (D,L) norvaline were incubated with Na-montmorillonite at 100% CEC at three hydrogen ion concentrations, and amino acid adsorption was determined by ion exchange chromatography. Enantiomers were analyzed by gas chromatography. Differences in the quantities of D and L enantiomers in any of the fractions was no larger than a few percent. Although a large difference in the adsorption of the amino acid enantiomers was not observed, the analysis may indicate a small preferential adsorption (0.5-2%) of L-amino acids by Na-montmorillonite.

Friebele, E.↗
NASA NTRS1985

Chemical and electrochemical behavior of the Cr(III)/Cr(II) half-cell in the iron-chromium redox energy storage system

The Cr(III) complexes present in the acidified chromium solutions used in the iron-chromium redox energy storage system have been isolated and identified as Cr(H2O)6(3+) and Cr(H2O)5Cl(2+) by ion-exchange chromatography and visible spectrophotometry. The cell reactions during charge-discharge cycles have been followed by means of visible spectrophotometry. The spectral bands were resolved into component peaks and concentrations of the Cr(III) species calculated using Beer's law. During the charge mode, Cr(H2O)5Cl(2+) is reduced to Cr(H2O)5Cl(+), and during the discharge mode Cr(H2O)5Cl(+) is oxidized back to Cr(H2O)5Cl(2+). Electrode potential measurements also support this interpretation. Hysteresis effects in the charge-discharge curves can be explained by the slow attainment of equilibrium between Cr(H2O)6(3+) and Cr(H2O)5Cl(2+).

Johnson, D. A.↗
NASA NTRS1996

Feeding Frequency Affects Cultured Rat Pituitary Cells in Low Gravity

In this report, we describe the results of a rat pituitary cell culture experiment done on STS-65 in which the effect of cell feeding on the release of the six anterior pituitary hormones was studied. We found complex microgravity related interactions between the frequency of cell feeding and the quantity and quality (i.e. biological activity) of some of the six hormones released in flight. Analyses of growth hormone (GH) released from cells into culture media on different mission days using gel filtration and ion exchange chromatography yielded qualitatively similar results between ground and flight samples. Lack of cell feeding resulted in extensive cell clumping in flight (but not ground) cultures. Vigorous fibroblast growth occurred in both ground and flight cultures fed 4 times. These results are interpreted within the context of autocrine and or paracrine feedback interactions. Finally the payload specialist successfully prepared a fresh trypsin solution in microgravity, detached the cells from their surface and reinserted them back into the culture chamber. These cells reattached and continued to release hormone in microgravity. In summary, this experiment shows that pituitary cells are microgravity sensitive and that coupled operations routinely associated with laboratory cel1 culture can also be accomplished in low gravity.

Hymer, W. C.↗
NASA NTRSDate not supplied

Center for Isotope Cosmochemistry and Geochronology at NASA Johnson Space Center

Ten years in the making the Center for Isotope Cosmochemistry and Geochronology (CICG) at NASA Johnson Space Center is designed to be a cooperative analytical facility where novel techniques are developed and performed. Our team works collaboratively to operate this integrated lab suite comprising sample preparation, metal-free clean chemistry, and mass spectrometers to measure a wide variety of elements and isotopes in astromaterials. Contamination control is enacted throughout by a positive pressure cascade of HEPA filtered air, weekly surface cleaning and particle counting. Astromaterials processing is performed with application-specific mortar and pestles, heavy liquid separation, a Frantz magnetic separator, as well as hand-picking using optical microscopes in laminar flow boxes. Microsampling is also carried out using a New Wave MicroMill. Elements for isotopic analysis are isolated from acid-digested samples using ion-exchange chromatography. Cross-contamination is minimized with dedicated laminar flow boxes and labware for different purification protocols. Instrumentation includes a ThermoFisher Element XR inductively coupled plasma mass spectrometer (ICP-MS) for quantification of elemental concentrations in dissolved sample solutions. For in situ analysis, a Teledyne Photon Machines Analyte Excite+ laser ablation system is coupled to the Element XR. The ThermoFisher Triton thermal ionization mass spectrometer (TIMS) is used to measure the isotopic composition of elements such as CA, K, Cr, Rb, Sr, Sm, Nd at high precision in processed samples. For a more diverse range of isotopic analyses, CICG houses a Nu Sapphire 1700 multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS), which is a large geometry instrument with a multi-pole collision cell for interference removal. An Applied Spectra Instruments J200 femto-second laser is planned for install this Fall and will be coupled to the Nu Sapphire 1700. NASA’s Internal Scientist Funding Model (ISFM)supports this facility. Advanced analytical geochemistry techniques are applied to targeted astromaterials to address important problems in planetary sciences, with a longer-term goal of preparing for samples collected and returned by space missions. CICG is open to collaborations on projects that utilize the facility’s unique capabilities and are within its research scope. We are particularly eager to support and share expertise with the next generation of planetary scientists.

Justin I Simon↗
NASA NTRS1995

Purification and stability characterization of a cell regulatory sialoglycopeptide inhibitor

Previous attempts to physically separate the cell cycle inhibitory and protease activities in preparations of a purified cell regulatory sialoglycopeptide (CeReS) inhibitor were largely unsuccessful. Gradient elution of the inhibitor preparation from a DEAE HPLC column separated the cell growth inhibitor from the protease, and the two activities have been shown to be distinct and non-overlapping. The additional purification increased the specific biological activity of the CeReS preparation by approximately two-fold. The major inhibitory fraction that eluted from the DEAE column was further analyzed by tricine-SDS-PAGE and microbore reverse phase HPLC and shown to be homogeneous in nature. Two other fractions separated by DEAE HPLC, also devoid of protease activity, were shown to be inhibitory to cell proliferation and most likely represented modified relatives of the CeReS inhibitor. The highly purified CeReS was chemically characterized for amino acid and carbohydrate composition and the role of the carbohydrate in cell proliferation inhibition, stability, and protease resistance was assessed.

Non-NASA Center↗
NASA NTRS2001

RNA isolation and fractionation with compaction agents

A new approach to the isolation of RNA from bacterial lysates employs selective precipitation by compaction agents, such as hexammine cobalt and spermidine. Using 3.5 mM hexammine cobalt, total RNA can be selectively precipitated from a cell lysate. At a concentration of 2 mM hexammine cobalt, rRNA can be fractionated from low molecular weight RNA. The resulting RNA mixture is readily resolved to pure 5S and mixed 16S/23S rRNA by nondenaturing anion-exchange chromatography. Using a second stage of precipitation at 8 mM hexammine cobalt, the low molecular weight RNA fraction can be isolated by precipitation. Compaction precipitation was also applied to the purification of an artificial stable RNA derived from Escherichia coli 5S rRNA and to the isolation of an Escherichia coli-expressed ribozyme. Copyright 2001 Academic Press.

Non-NASA Center↗
NASA NTRS1996

Identification of Ser-543 as the major regulatory phosphorylation site in spinach leaf nitrate reductase

Spinach leaf NADH:nitrate reductase (NR) responds to light/dark signals and photosynthetic activity in part as a result of rapid regulation by reversible protein phosphorylation. We have identified the major regulatory phosphorylation site as Ser-543, which is located in the hinge 1 region connecting the cytochrome b domain with the molybdenum-pterin cofactor binding domain of NR, using recombinant NR fragments containing or lacking the phosphorylation site sequence. Studies with NR partial reactions indicated that the block in electron flow caused by phosphorylation also could be localized to the hinge 1 region. A synthetic peptide (NR6) based on the phosphorylation site sequence was phosphorylated readily by NR kinase (NRk) in vitro. NR6 kinase activity tracked the ATP-dependent inactivation of NR during several chromatographic steps and completely inhibited inactivation/phosphorylation of native NR in vitro. Two forms of NRk were resolved by using anion exchange chromatography. Studies with synthetic peptide analogs indicated that both forms of NRk had similar specificity determinants, requiring a basic residue at P-3 (i.e., three amino acids N-terminal to the phosphorylated serine) and a hydrophobic residue at P-5. Both forms are strictly calcium dependent but belong to distinct families of protein kinases because they are distinct immunochemically.

NASA Discipline Plant Biology↗
NASA NTRS1987

The evaporation path of seawater and the coprecipitation of Br- and K+ with halite

Brines and salt were sampled at the Morton Bahamas solar salt production facility on Great Inagua Island in the Bahamas. The brines were analyzed by ion chromatography to define more precisely than heretofore the evaporation path of seawater to the end of the halite facies. At Inagua, calcium carbonate begins to precipitate at a brine concentration factor of 1.8 times that of seawater. Gypsum begins to precipitate at a brine concentration of 3.8 times seawater, and halite at a concentration factor of 10.6. Three of the most concentrated brines from Inagua (40 times seawater) were evaporated further in the laboratory. Magnesium sulfate first precipitated at brine concentrations about 70 times those of seawater, and potassium-bearing phases began to precipitate for these brines at concentrations greater than 90 times those of seawater. The distribution of coefficients of Br- and K+ between brines and halite were determined by combining analytical data for the Inagua brines with measurements of the Br- and K+ content of halites from Inagua and of halite which had precipitated from Inagua brines during storage. The observed average value of DBr- is 0.032, in good agreement with some of the previous measurements. The measured values of DK+ are highly variable (0.001 to 0.021); DK+ for halite precipitated early in the halite facies is in the vicinity of 0.015.

NASA Discipline Exobiology↗
NASA NTRS1989

Purification and identification of the fusicoccin binding protein from oat root plasma membrane

Fusicoccin (FC), a fungal phytotoxin, stimulates the H(+) -ATPase located in the plasma membrane (PM) of higher plants. The first event in the reaction chain leading to enhanced H(+) -efflux seems to be the binding of FC to a FC-binding protein (FCBP) in the PM. We solubilized 90% of the FCBP from oat (Avena sativa L. cv Victory) root PM in an active form with 1% octyl-glucoside. The FCBP was stabilized by the presence of protease inhibitors. The FCBP was purified by affinity chromatography using FC-linked adipic acid dihydrazide agarose (FC-AADA). Upon elution with 8 molar urea, two major protein bands on sodium dodecyl sulfate-polyaerylamide gel electrophoresis with molecular weights of 29,700 and 31,000 were obtained. Successive chromatography on BBAB Bio-Gel A, hexyl agarose, and FC-AADA resulted in the same two bands when the FC-AADA was eluted with sodium dodecyl sulfate. A direct correlation was made between 3H-FC-binding activity and the presence of the two protein bands. The stoichiometry of the 29,700 and 31,000 molecular weight bands was 1:2. This suggests that the FCBP occurs in the native form as a heterotrimer with an apparent molecular weight of approximately 92,000.

NASA Discipline Number 29-20↗
NASA NTRS2000

Nonbiological fractionation of iron isotopes

Laboratory experiments demonstrate that iron isotopes can be chemically fractionated in the absence of biology. Isotopic variations comparable to those seen during microbially mediated reduction of ferrihydrite are observed. Fractionation may occur in aqueous solution during equilibration between inorganic iron complexes. These findings provide insight into the mechanisms of iron isotope fractionation and suggest that nonbiological processes may contribute to iron isotope variations observed in sediments.

NASA Discipline Exobiology↗
NASA NTRS1994

Responses of soybean to ammonium and nitrate supplied in combination to the whole root system or separately in a split-root system

To address the questions of whether allocation of carbohydrates to roots is influenced by ionic form of nitrogen absorbed and whether allocation of carbohydrates to roots in turn influences proportionality between NH4+ and NO3- uptake from mixed sources, NH4+ and NO3- were supplied separately to halves of a split-root hydroponic system and were supplied in combination to a whole-root system. Dry matter accumulation in the split-root system was 18% less in the NH4(+)-fed axis than in the NO3(-)-fed axis. This, however, does not indicate that partitioning of carbohydrate between the two axes was different. Most of the reduction in dry matter accumulation in the NH4(+)-fed axis can be accounted for by the retransport of CH2O equivalents from the root back to the shoot with amino acids produced by NH4+ assimilation. Uptake of NH4+ or NO3- by the respective halves of the split-root system was proportional to the estimated allocation of carbohydrate to that half. When NH4+ and NO3- were supplied to separate halves of the split-root system, the cumulative NH4+ to NO3- uptake ratio was 0.81. When supplied in combination to the whole-root system, the cumulative NH4+ to NO3- uptake ratio was 1.67. Thus, while the shoot may affect total nitrogen uptake through the export of carbohydrates to roots, the shoot (common for halves of the split-root system) apparently does not exert a direct effect on proportionality of NH4+ and NO3- uptake by roots. For whole roots supplied with both NH4+ and NO3-, the restriction in uptake of NO3- may involve a stimulation of NO3- efflux rather than an inhibition of NO3- influx. While only the net uptake of NH4+ and NO3- was measured by ion chromatography, monitoring at approximately hourly intervals during the first 3 days of treatment revealed irregularly occurring intervals of both depletion (net influx) and enrichment (net efflux) in solutions. In the case of NH4+, numbers of net efflux events were similar (21 to 24 out of 65 sequential sampling intervals) whether NH4+ was supplied with NO3- to whole-root systems or separately to an axis of the split-root system. In the case of NO3-, however, the number of net efflux events increased from 8 when NO3- was supplied to a separate axis of the split-root system to between 19 and 24 when NO3- was supplied with NH4+ to whole-root systems.

Non-NASA Center↗
NASA NTRS1996

Calcium kinetics with microgram stable isotope doses and saliva sampling

Studies of calcium kinetics require administration of tracer doses of calcium and subsequent repeated sampling of biological fluids. This study was designed to develop techniques that would allow estimation of calcium kinetics by using small (micrograms) doses of isotopes instead of the more common large (mg) doses to minimize tracer perturbation of the system and reduce cost, and to explore the use of saliva sampling as an alternative to blood sampling. Subjects received an oral dose (133 micrograms) of 43Ca and an i.v. dose (7.7 micrograms) of 46Ca. Isotopic enrichment in blood, urine, saliva and feces was well above thermal ionization mass spectrometry measurement precision up to 170 h after dosing. Fractional calcium absorptions determined from isotopic ratios in blood, urine and saliva were similar. Compartmental modeling revealed that kinetic parameters determined from serum or saliva data were similar, decreasing the necessity for blood samples. It is concluded from these results that calcium kinetics can be assessed with micrograms doses of stable isotopes, thereby reducing tracer costs and with saliva samples, thereby reducing the amount of blood needed.

Clinical Trial↗
NASA NTRS1992

Purification and sequence analysis of two rat tissue inhibitors of metalloproteinases

Two protein inhibitors of metalloproteinases (TIMP) were isolated from medium conditioned by the clonal rat osteosarcoma line UMR 106-01. Initial purification of both a 30-kDa inhibitor and a 20-kDa inhibitor was accomplished using heparin-Sepharose chromatography with dextran sulfate elution followed by DEAE-Sepharose and CM-Sepharose chromatography. Purification of the 20-kDa inhibitor to homogeneity was completed with reverse-phase high-performance liquid chromatography. The 20-kDa inhibitor was identified as rat TIMP-2. The 30-kDa inhibitor, although not purified to homogeneity, was identified as rat TIMP-1. Amino terminal amino acid sequence analysis of the 30-kDa inhibitor demonstrated 86% identity to human TIMP-1 for the first 22 amino acids while the sequence of the 20-kDa inhibitor was identical to that of human TIMP-2 for the first 22 residues. Treatment with peptide:N-glycosidase F indicated that the 30-kDa rat inhibitor is glycosylated while the 20-kDa inhibitor is apparently unglycosylated. Inhibition of both rat and human interstitial collagenase by rat TIMP-2 was stoichiometric, with a 1:1 molar ratio required for complete inhibition. Exposure of UMR 106-01 cells to 10(-7) M parathyroid hormone resulted in approximately a 40% increase in total inhibitor production over basal levels.

NASA Discipline Musculoskeletal↗
NASA NTRS1995

Simultaneous concentration and purification through gradient deformation chromatography

Mobile-phase additives, commonly used to modulate absorbate retention in gradient elution chromatography, are usually assumed to be either linearly retained or unretained. Previous theoretical work from our laboratory has shown that these modulators, such as salts in ion-exchange and hydrophobic interaction chromatography and organic modifiers in reversed-phase chromatography, can absorb nonlinearly, giving rise to gradient deformation. Consequently, adsorbate peaks that elute in the vicinity of the head of the deformed gradient may exhibit unusual shapes, form shoulders, and/or be concentrated. These effects for a reversed-phase sorbent with aqueous acetonitrile (ACN) as the modulator are verified experimentally. Gradient deformation is demonstrated experimentally and agrees with simulations based on ACN isotherm parameters that are independently determined from batch equilibrium studies using the layer model. Unusual absorbate peak shapes were found experimentally for single-component injections of phenylalanine, similar to those calculated by the simulations. A binary mixture of tryptophan and phenylalanine is used to demonstrate simultaneous concentration and separation, again in agreement with simulations. The possibility of gradient deformation in ion-exchange and hydrophobic interaction chromatography is discussed.

NASA Discipline Number 93-10↗
NASA NTRS1999

Characterization of Human Bone Alkaline Phosphatase in Pichia Pastoris

A soluble form of human bone alkaline phosphatase has been expressed in a recombinant strain of the methylotrophic yeast Pichia pastoris. We constructed a plasmid containing cDNA encoding for human bone alkaline phosphatase, with the hydrophobic carboxyl terminal portion deleted. Alkaline phosphatase was secreted into the medium to a level of 32mg/L when cultured in shake flasks, and enzyme activity was 12U/mg, as measured by a spectrophotometric assay. By conversion to a fermentation system, a yield of 880mg/L has been achieved with an enzyme activity of 968U/mg. By gel electrophoresis analysis, it appears that greater than 50% of the total protein in the fermentation media is alkaline phosphatase. Although purification procedures are not yet completely optimized, they are expected to include filtration, ion exchange and affinity chromatography. Our presentation will focus on the purification and crystallization results up to the time of the conference. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

Malone, Christine C.↗