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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Molecular aspects of stress-gene regulation during spaceflight

Spaceflight-associated stress has been the topic of investigation since the first terrestrial organisms were exposed to this unique environment. Organisms that evolved under the selection pressures of earth-normal environments can perceive spaceflight as a stress, either directly because gravity influences an intrinsic biological process, or indirectly because of secondary effects imparted by spaceflight upon environmental conditions. Different organisms and even different organs within an organism adapt to a spaceflight environment with a diversity of tactics. Plants are keenly sensitive to gravity for directed development, and are also sensitive to other stresses associated with closed-system spaceflight environments. Within the past decade, the tools of molecular biology have begun to provide a sophisticated evaluation of spaceflight-associated stress and the genetic responses that accompany metabolic adaptation to spaceflight.

manned↗
NASA NTRS1992

Opportunities for research on Space Station Freedom

NASA has allocated research accommodations on Freedom (equipment, utilities, etc.) to the program offices that sponsor space-based research and development as follows: Space Science and Applications (OSSA)--52 percent, Commercial Programs (OCP)--28 percent, Aeronautics and Space Technology (OAST)--12 percent, and Space Flight (OSF)--8 percent. Most of OSSA's allocation will be used for microgravity and life science experiments; although OSSA's space physics, astrophysics, earth science and applications, and solar system exploration divisions also will use some of this allocation. Other Federal agencies have expressed an interest in using Space Station Freedom. They include the National Institutes of Health (NIH), U.S. Geological Survey, National Science Foundation, National Oceanic and Atmospheric Administration, and U.S. Departments of Agriculture and Energy. Payload interfaces with space station lab support equipment must be simple, and experiment packages must be highly contained. Freedom's research facilities will feature International Standard Payload Racks (ISPR's), experiment racks that are about twice the size of a Spacelab rack. ESA's Columbus lab will feature 20 racks, the U.S. lab will have 12 racks, and the Japanese lab will have 10. Thus, Freedom will have a total of 42 racks versus 8 for Space lab. NASA is considering outfitting some rack space to accommodate small, self-contained payloads similar to the Get-Away-Special canisters and middeck-locker experiment packages flown on Space Shuttle missions. Crew time allotted to experiments on Freedom at permanently occupied capability will average 25 minutes per rack per day, compared to six hours per rack per day on Spacelab missions. Hence, telescience--the remote operation of space-based experiments by researchers on the ground--will play a very important role in space station research. Plans for supporting life sciences research on Freedom focus on the two basic goals of NASA 's space life sciences program: to ensure the health, safety, and productivity of humans in space and to acquire fundamental knowledge of biological processes. Space-based research has already shown that people and plants respond the same way to the microgravity environment: they lose structure. However, the mechanisms by which they respond are different, and researchers do not yet know much about these mechanisms. Life science research accommodations on Freedom will include facilities for experiments designed to address this and other questions, in fields such as gravitational biology, space physiology, and biomedical monitoring and countermeasures research.

Phillips, Robert W.↗
DOE OSTI2019

Effect of an Antimicrobial Peptide on Lateral Segregation of Lipids: A Structure and Dynamics Study by Neutron Scattering

Antimicrobial peptides are one of the most promising classes of antibiotic agents for drug-resistant bacteria. Although the mechanisms of their action are not fully understood, many of them are found to interact with the target bacterial membrane, causing different degrees of perturbations. In this work, we directly observed that a short peptide disturbs membranes by inducing lateral segregation of lipids without forming pores or destroying membranes. Aurein 1.2 (aurein) is a 13-amino acid antimicrobial peptide discovered in the frog Litoria genus that exhibits high antibiotic efficacy. Being cationic and amphiphilic, it binds spontaneously to a membrane surface with or without charged lipids. With a small-angle neutron scattering contrast matching technique that is sensitive to lateral heterogeneity in membrane, we found that aurein induces significant lateral segregation in an initially uniform lipid bilayer composed of zwitterionic lipid and anionic lipid. More intriguingly, the lateral segregation was similar to the domain formed below the order–disorder phase-transition temperature. To our understanding, this is the first direct observation of lateral segregation caused by a peptide. With quasi-elastic neutron scattering, we indeed found that the lipid lateral motion in the fluid phase was reduced even at low aurein concentrations. The reduced lateral mobility makes the membrane prone to additional stresses and defects that change membrane properties and impede membrane-related biological processes. Thus, our results provide insights into how a short peptide kills bacteria at low concentrations without forming pores or destroying membranes. With a better understanding of the interaction, more effective and economically antimicrobial peptides may be designed.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Rewiring the unfolded protein response for plant growth recovery after stress

The unfolded protein response (UPR) is a highly coordinated signaling network that alleviates endoplasmic reticulum (ER) stress, a condition induced by diverse environmental challenges in plants. Over the past two decades, substantial progress has been made in elucidating the genetic and molecular mechanisms of ER stress sensing and signal transduction in plants, largely through studies in the model plant Arabidopsis thaliana . These advances have established the UPR as a central regulator of proteostasis and underscored its broader relevance to plant growth and development and crop productivity under stress conditions. Despite this progress, critical knowledge gaps remain, particularly concerning the downstream biological processes required for growth recovery once ER stress has subsided and how these processes are coordinated by UPR regulators. Recent systems-level and integrative studies have begun to reveal critical roles of UPR signaling in pathways governing growth re-establishment and homeostasis of nutrient allocation and energy metabolism. In this review, we highlight recent findings on the functional roles of the plant UPR in recovery from ER stress, with a focus on mechanisms mediated by UPR regulators and downstream biological pathways that enable the transition from stress mitigation to growth restoration. Although this research area is still emerging, accumulating evidence supports a model in which the UPR functions as a dynamic regulatory network that actively coordinates post-stress physiological recovery to support plant fitness.

ER stress↗
DOE OSTI2026

Bioorthogonal Click Chemistry for Antibody-Free Profiling of Acetylation, Propionylation, and Butyrylation in Pseudomonas aeruginosa and Methicillin-Resistant Staphylococcus aureus

Lysine acylation is a posttranslational modification (PTM) conserved in all domains of life and is essential for regulating diverse biological processes. Traditional methods for investigating acylation rely on anti-acyl-lysine antibodies, which are costly and time-consuming and often exhibit variable affinity. To remedy these pitfalls, we developed an antibody-free method for bacterial acylome enrichment using bioorthogonal click chemistry coupled with tandem mass spectrometry. We applied this approach to the pathogens Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) to explore the biological significance of acylation in each organism. We characterized the acetylome, propionylome, and butyrylome in P. aeruginosa UCBPP-PA14 and the acetylome and propionylome in MRSA. Comparative analyses revealed unique PTM dynamics showing that acylation regulated a wide range of cellular functions, including metabolism, antibiotic resistance, virulence, and stress response. This work establishes the first antibody-free enrichment method for defining bacterial acylomes and provides new insight into global lysine acylation networks in pathogenic bacteria.

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

Cell-free gene expression: an expanded repertoire of applications

Cell-free biology is the activation of biological processes without the use of intact living cells. It has been used for more than 50 years across the life sciences as a foundational research tool, but a recent technical renaissance has facilitated high-yielding (grams of protein per litre), cell-free gene expression systems from model bacteria, the development of cell-free platforms from non-model organisms and multiplexed strategies for rapidly assessing biological design. These advances provide exciting opportunities to profoundly transform synthetic biology by enabling new approaches to the model-driven design of synthetic gene networks, the fast and portable sensing of compounds, on-demand biomanufacturing, building cells from the bottom up, and next-generation educational kits.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1988

Exploring the living universe: A strategy for space life sciences

The status and goals of NASA's life sciences programs are examined. Ways and mean for attaining these goals are suggested. The report emphasizes that a stronger life sciences program is imperative if the U.S. space policy is to construct a permanently manned space station and achieve its stated goal of expanding the human presence beyond earth orbit into the solar system. The same considerations apply in regard to the other major goal of life sciences: to study the biological processes and life in the universe. A principal recommendation of the report is for NASA to expand its program of ground- and space-based research contributing to resolving questions about physiological deconditioning, radiation exposure, potential psychological difficulties, and life support requirements that may limit stay times for personnel on the Space Station and complicate missions of more extended duration. Other key recommendations call for strengthening programs of biological systems research in: controlled ecological life support systems for humans in space, earth systems central to understanding the effects on the earth's environment of both natural and human activities, and exobiology.

Source record↗
DOE OSTI2019

Identification of bioactive metabolites using activity metabolomics

The metabolome, the collection of small-molecule chemical entities involved in metabolism, has traditionally been studied with the aim of identifying biomarkers in the diagnosis and prediction of disease. However, the value of metabolome analysis (metabolomics) has been redefined from a simple biomarker identification tool to a technology for the discovery of active drivers of biological processes. It is now clear that the metabolome affects cellular physiology through modulation of other ‘omics’ levels, including the genome, epigenome, transcriptome and proteome. In this Review, we focus on recent progress in using metabolomics to understand how the metabolome influences other omics and, by extension, to reveal the active role of metabolites in physiology and disease. Furthermore, this concept of utilizing metabolomics to perform activity screens to identify biologically active metabolites — which we term activity metabolomics — is already having a broad impact on biology.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Linking Hydrobiogeochemical Processes and Management Techniques to Close Nutrient Loops in an Arid River

In this study, we explore opportunities to optimize food-energy-water (FEW) resources by closing nutrient loops in arid-land rivers. Specifically, we evaluate source and sink behavior of nitrogen as nitrate (NO 3 -N) in three characteristic channels in the Middle Rio Grande Basin (Delivery and Drain channels associated with agriculture and the main channel of the Rio Grande). All three channels are located downstream of a large wastewater treatment plant that is the main contributor of nutrients to this reach of the Rio Grande. We used a mass balance approach paired with stable isotope analysis to determine sources and processing of NO 3 -N within the channels over time (a year) and through space (along ~15 to 50 km reaches). Results indicated the growing season was an important period of sink behavior for the Delivery channel and the Rio Grande, but the Drain channel was a year-round source. Stable isotope analysis of 15 N and 18 O found a distinct nitrate signature in the Drain associated with biological processing, as well as Rio Grande sites impacted by agricultural outflow, but no equivalent signature was present in the Delivery channel. Based on our findings, we provide recommendations to help close nutrient loops in the study system and analogous aridland irrigation networks by 1) minimizing loss during the transfer of nutrients from wastewater facilities to agricultural areas, and 2) minimizing enrichment to downstream aquatic ecosystems by sequestering nutrients that escape the nutrient loop.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Bump-and-Hole Engineering Identifies Specific Substrates of Glycosyltransferases in Living Cells

Studying posttranslational modifications classically relies on experimental strategies that oversimplify the complex biosynthetic machineries of living cells. Protein glycosylation contributes to essential biological processes, but correlating glycan structure, underlying protein, and disease-relevant biosynthetic regulation is currently elusive. Here, we engineer living cells to tag glycans with editable chemical functionalities while providing information on biosynthesis, physiological context, and glycan fine structure. We introduce a non-natural substrate biosynthetic pathway and use engineered glycosyltransferases to incorporate chemically tagged sugars into the cell surface glycome of the living cell. We apply the strategy to a particularly redundant yet disease-relevant human glycosyltransferase family, the polypeptide N-acetylgalactosaminyl transferases. This approach bestows a gain-of-chemical-functionality modification on cells, where the products of individual glycosyltransferases can be selectively characterized or manipulated to understand glycan contribution to major physiological processes.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Fostering Peat Moss Feedbacks to Accelerate Peatland Restoration

Extensive knowledge exists on plant-species traits and functions, but we understand less about how population- or community-level emergent traits influence ecosystem functioning. This knowledge gap is important for ecosystems like peatlands, arid drylands, salt marshes, seagrass meadows and mangroves, where emergent traits of plant communities can create plant-environment feedbacks that amplify or dampen ecosystem processes. Recent insights from restoration ecology suggest that these feedbacks can critically influence restoration success. Despite growing recognition of emergent trait-driven feedbacks in other ecosystems, they remain underexplored in peatland restoration, world’s most carbon-dense ecosystem. Here, we review emergent self-amplifying and self-dampening feedbacks with net positive effects for peat moss-dominated systems. We show how these feedbacks can promote key physical, chemical, and biological processes that enhance peat moss growth, increase water retention, and reduce microbial decomposition of organic matter. Understanding and fostering these feedbacks offers a promising framework to accelerate peatland restoration across diverse degradation states.

Sphagnum↗
NASA NTRS2008

The Aerosol/Cloud/Ecosystems Mission (ACE)

The goals and measurement strategy of the Aerosol/Cloud/Ecosystems Mission (ACE) are described. ACE will help to answer fundamental science questions associated with aerosols, clouds, air quality and global ocean ecosystems. Specifically, the goals of ACE are: 1) to quantify aerosol-cloud interactions and to assess the impact of aerosols on the hydrological cycle and 2) determine Ocean Carbon Cycling and other ocean biological processes. It is expected that ACE will: narrow the uncertainty in aerosol-cloud-precipitation interaction and quantify the role of aerosols in climate change; measure the ocean ecosystem changes and precisely quantify ocean carbon uptake; and, improve air quality forecasting by determining the height and type of aerosols being transported long distances. Overviews are provided of the aerosol-cloud community measurement strategy, aerosol and cloud observations over South Asia, and ocean biology research goals. Instruments used in the measurement strategy of the ACE mission are also highlighted, including: multi-beam lidar, multiwavelength high spectra resolution lidar, the ocean color instrument (ORCA)--a spectroradiometer for ocean remote sensing, dual frequency cloud radar and high- and low-frequency micron-wave radiometer. Future steps for the ACE mission include refining measurement requirements and carrying out additional instrument and payload studies.

Schoeberl, Mark↗
DOE OSTI2017

A novel signal transduction protein: Combination of solute binding and tandem PAS-like sensor domains in one polypeptide chain: Periplasmic Ligand Binding Protein Dret_0059

We report the structural and biochemical characterization of a novel periplasmic ligand-binding protein, Dret_0059, from Desulfohalobium retbaense DSM 5692, an organism isolated from the Salt Lake Retba in Senegal. The structure of the protein consists of a unique combination of a periplasmic solute binding protein (SBP) domain at the N-terminal and a tandem PAS-like sensor domain at the C-terminal region. SBP domains are found ubiquitously and their best known function is in solute transport across membranes. PAS-like sensor domains are commonly found in signal transduction proteins. These domains are widely observed as parts of many protein architectures and complexes but have not been observed previously within the same polypeptide chain. In the structure of Dret_0059, a ketoleucine moiety is bound to the SBP, whereas a cytosine molecule is bound in the distal PAS-like domain of the tandem PAS-like domain. Differential scanning flourimetry support the binding of ligands observed in the crystal structure. There is significant interaction between the SBP and tandem PAS-like domains, and it is possible that the binding of one ligand could have an effect on the binding of the other. We uncovered three other proteins with this structural architecture in the non-redundant sequence data base, and predict that they too bind the same substrates. The genomic context of this protein did not offer any clues for its function. We did not find any biological process in which the two observed ligands are coupled. The protein Dret_0059 could be involved in either signal transduction or solute transport.

Wu, R.↗
DOE OSTI2025

Unravelling the Glycan Code: Molecular Dynamics and Quantum Chemistry Reveal How O-Glycan Functional Groups Govern OgpA Selectivity in Mucin Degradation by Akkermansia muciniphila

Mucins, heavily O-glycosylated glycoproteins, are a key component of mucus, and certain gut microbiota, including Akkermansia muciniphila , can utilise mucin glycans as a carbon source. Akkermansia muciniphila produces the O-glycopeptidase enzyme OgpA, which cleaves peptide bonds at the N-terminus of serine (Ser) or threonine (Thr) residues carrying O-glycan substitutions, with selectivity influenced by the O-glycan functional groups. Using molecular dynamics (MD) simulations and quantum chemistry calculations, we explored how different O-glycan groups affect OgpA's selectivity. Our results show that peptides bind to the enzyme via hydrogen bonds, π–π interactions, van der Waals forces and electrostatic interactions, with key residues, including Tyr90, Val138, Gly176, Tyr210 and Glu91, playing important roles. The primary determinant of selectivity is the interaction between the peptide's functional group and the enzyme's binding cavity, while peptide–enzyme interface interactions are secondary. Quantum chemistry calculations reveal that OgpA prefers peptides with a lower electrophilic character. This study provides new insights into mucin degradation by gut microbiota enzymes, advancing our understanding of this critical biological process.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Organ-delimited gene regulatory networks provide high accuracy in candidate transcription factor selection across diverse processes

Organ-specific gene expression datasets that include hundreds to thousands of experiments allow the reconstruction of organ-level gene regulatory networks (GRNs). However, creating such datasets is greatly hampered by the requirements of extensive and tedious manual curation. Here, we trained a supervised classification model that can accurately classify the organ-of-origin for a plant transcriptome. This K-Nearest Neighbor-based multiclass classifier was used to create organ-specific gene expression datasets for the leaf, root, shoot, flower, and seed in Arabidopsis thaliana . A GRN inference approach was used to determine the: i. influential transcription factors (TFs) in each organ and, ii. most influential TFs for specific biological processes in that organ. These genome-wide, organ-delimited GRNs (OD-GRNs), recalled many known regulators of organ development and processes operating in those organs. Importantly, many previously unknown TF regulators were uncovered as potential regulators of these processes. As a proof-of-concept, we focused on experimentally validating the predicted TF regulators of lipid biosynthesis in seeds, an important food and biofuel trait. Of the top 20 predicted TFs, eight are known regulators of seed oil content, e.g., WRI1, LEC1, FUS3. Importantly, we validated our prediction of MybS2, TGA4, SPL12, AGL18, and DiV2 as regulators of seed lipid biosynthesis. We elucidated the molecular mechanism of MybS2 and show that it induces purple acid phosphatase family genes and lipid synthesis genes to enhance seed lipid content. This general approach has the potential to be extended to any species with sufficiently large gene expression datasets to find unique regulators of any trait-of-interest.

09 BIOMASS FUELS↗
DOE OSTI2021

Construct design for CRISPR/Cas-based genome editing in plants

CRISPR construct design is a key step in the practice of genome editing, which includes identification of appropriate Cas proteins, design and selection of guide RNAs (gRNAs), and selection of regulatory elements to express gRNAs and Cas proteins. Here, we review the choices of CRISPR-based genome editors suited for different needs in plant genome editing applications. We consider the technical aspects of gRNA design and the associated computational tools. We also discuss strategies for the design of multiplex CRISPR constructs for high-throughput manipulation of complex biological processes or polygenic traits. We provide recommendations for different elements of CRISPR constructs and discuss the remaining challenges of CRISPR construct optimization in plant genome editing.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

MicroRNA-630 inhibits breast cancer progression by directly targeting BMI1

Highlights: • MiR-630 initiates apoptosis, blocks cell cycle progression and suppresses cell proliferation in breast cancer cells. • BMI1, a member of polycomb group family, is identified as a novel direct target of miR-630. • BMI1 mediates miR-630-suppressed breast cancer progression including apoptosis induction, cell cycle arrest, and proliferation inhibition. MicroRNAs (miRNAs) play critical roles in breast cancer cell biological processes, including proliferation and apoptosis by inhibiting the expression of their target genes. Herein, we reported that miR-630 overexpression initiates apoptosis, blocks cell cycle progression and suppresses cell proliferation in breast cancer cells. Furthermore, BMI1, a member of polycomb group family, was identified as a direct target of miR-630, and there was a negative correlation between the expression levels of BMI1 and miR-630 in human breast cancer samples. With a series of biology approaches, subsequently, we proved that BMI1 was a functional downstream target of miR-630 and mediated the property of miR-630-dependent inhibition of breast cancer progression. Taken together, these findings provide further evidence on the tumor-suppression function of miR-630 in breast cancer, and clarify BMI1 as a novel functional target gene of miR-630.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Intra-Molecular Isotope Study of Light Hydrocarbons

Light hydrocarbons (C 1 -C 10 ) are the largest fraction of petroleum hydrocarbons and some of the most ubiquitous and mobile fluids within sedimentary basins. It has been increasingly recognized that hydrocarbons of varying chain-lengths can be stable even under mantle conditions and that their fluxes may play a key role in the carbon dynamics of the Earth. Major formation mechanisms of these light hydrocarbons include microbial, thermogenic, and abiogenic origins. Despite their proven utility, conventional approaches using the bulk or global stable isotopes of light hydrocarbons are often not sufficient to distinguish their sources (particularly, biogenic vs. abiogenic), maturation stages/temperatures, and migration-degradation processes. Most natural compounds, including light hydrocarbons, are composed of a set of diverse isotopic molecules that differ in the number of isotopic substitutions and/or positions of isotopic substitution within a given molecules. Many of light hydrocarbon molecules contain hydrogen and carbon in energetically non-equivalent positions: isotopomers or position-specific (intra-molecular) isotope fractionation. Position-specific isotopic compositions can differ due either to equilibrium or to path-dependent kinetic or biological processes. Thus, the position-specific isotopic fractionation between different carbon and hydrogen positions within a single molecular compound could be used regardless of their reactants and other products. We hypothesize that the formation, transport and degradation processes of light hydrocarbons in the subsurface induce and control significant, perhaps unique position-specific 13 C/ 12 C and 2 H/ 1 H isotope fractionation. In this proposal, we propose to develop a new dimension in stable isotope geochemistry of light hydrocarbons: intra-molecular isotope study of light hydrocarbons. The specific objectives of our proposal include: (a) develop robust and routine quantitative nuclear magnetic resonance (NMR) methods for high-precision/high-accuracy isotopomer analysis of propane and other light hydrocarbons (C 3 -C 10 ), (b) gain a first clear picture on position-specific δ 2 H and δ 13 C values of select light hydrocarbons of both natural and industrial sources, including samples of natural gases (C 3 and possibly C 4 -C 5 ) collected from select sedimentary basins with conventional and unconventional reservoirs, (c) acquire information on position-specific 13 C/ 12 C and 2 H/ 1 H isotope fractionation of light hydrocarbons in key natural processes (thermogenic formation and oxidative degradation) based on well-controlled laboratory experiments, and (d) establish a general framework for interpreting/modeling position-specific 13 C/ 12 C and 2 H/ 1 H isotope compositions of light hydrocarbons. Intra-molecular isotope study of light hydrocarbons is expected to open up great potentials that the bulk and position-specific isotope fractionation of light hydrocarbons, in combination with mathematical/theoretical kinetic models, could provide unprecedented wealth of information on the sources, transport, and sinks of light hydrocarbons in sedimentary basins and deep Earth.

03 NATURAL GAS↗