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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Biological Based Risk Assessment for Space Exploration

Exposures from galactic cosmic rays (GCR) - made up of high-energy protons and high-energy and charge (HZE) nuclei, and solar particle events (SPEs) - comprised largely of low- to medium-energy protons are the primary health concern for astronauts for long-term space missions. Experimental studies have shown that HZE nuclei produce both qualitative and quantitative differences in biological effects compared to terrestrial radiation, making risk assessments for cancer and degenerative risks, such as central nervous system effects and heart disease, highly uncertain. The goal for space radiation protection at NASA is to be able to reduce the uncertainties in risk assessments for Mars exploration to be small enough to ensure acceptable levels of risks are not exceeded and to adequately assess the efficacy of mitigation measures such as shielding or biological countermeasures. We review the recent BEIR VII and UNSCEAR-2006 models of cancer risks and their uncertainties. These models are shown to have an inherent 2-fold uncertainty as defined by ratio of the 95% percent confidence level to the mean projection, even before radiation quality is considered. In order to overcome the uncertainties in these models, new approaches to risk assessment are warranted. We consider new computational biology approaches to modeling cancer risks. A basic program of research that includes stochastic descriptions of the physics and chemistry of radiation tracks and biochemistry of metabolic pathways, to emerging biological understanding of cellular and tissue modifications leading to cancer is described.

Cucinotta, Francis A.↗
NASA NTRS2011

Operations Research Flight Ground Service Education/Outreach

This viewgraph presentation describes a nutritional biochemistry assessment of astronauts in preflight, in-flight, and post-flight operations. In-flight collections of blood and urine samples from astronauts to test the effects of Vitamin K, Pro K, Vitamin D, Omega-3 Fatty Acids, Iron, and Sodium in spaceflight is shown. A demonstration of a 1-carbon metabolism pathway that determines the existence of enzymes and polymorphisms is also presented.

Smith, Scott M.↗
NASA NTRS2013

The Search for Nitrates on Mars by the Sample Analysis at Mars (SAM) Instrument

Planetary models suggest that nitrogen was abundant in the early Martian atmosphere as N2 but it was lost by sputtering and photochemical loss to space, impact erosion, and chemical oxidation to nitrates. A nitrogen cycle may exist on Mars where nitrates, produced early in Mars' history, may have been later decomposed back into N2 by the current impact flux. Nitrates are a fundamental source of nitrogen for terrestrial microorganisms, and they have evolved metabolic pathways to perform both oxidation and reduction to drive a complete biological nitrogen cycle. Therefore, the characterization of nitrogen in Martian soils is important to assess habitability of the Martian environment, particularly with respect to the presence of nitrates. The only previous mission that was designed to search for soil nitrates was the Phoenix mission but N-containing species were not detected by TEGA or the MECA WCL. Nitrates have been tentatively identified in Nakhla meteorites, and if nitrogen was oxidized on Mars, this has important implications for the habitability potential of Mars. Here we report the results from the Sample Analysis at Mars (SAM) instrument suite aboard the Curiosity rover during the first year of surface operations in Gale Crater. Samples from the Rocknest aeolian deposit and sedimentary rocks (John Klein) were heated to approx 835degC under helium flow and the evolved gases were analyzed by MS and GC-MS. Two and possibly three peaks may be associated with the release of m/z 30 at temperatures ranging from 180degC to 500degC. M/z 30 has been tentatively identified as NO; other plausible contributions include CH2O and an isotopologue of CO, 12C18O. NO, CH2O, and CO may be reaction products of reagents (MTBSTFA/DMF) carried from Earth for the wet chemical derivatization experiments with SAM and/or derived from indigenous soil nitrogenated organics. Laboratory analyses indicate that it is also possible that <550degC evolved NO is produced via reaction of HCl with nitrates arising from the decomposition of perchlorates. All sources of m/z 30 whether it be martian or terrestrial will be considered and their implications for Mars will be discussed.

Navarro-Gonzalez, Rafael↗
NASA NTRS2015

Vision Issues and Space Flight: Evaluation of One-Carbon Metabolism Polymorphisms

Intermediates of the one-carbon metabolic pathway are altered in astronauts who experience vision-related issues during and after space flight. Serum concentrations of homocysteine, cystathionine, 2-methylcitric acid, and methylmalonic acid were higher in astronauts with ophthalmic changes than in those without (Zwart et al., J Nutr, 2012). These differences existed before, during, and after flight. Potential confounding factors did not explain the differences. Genetic polymorphisms could contribute to these differences, and could help explain why crewmembers on the same mission do not all have ophthalmic issues, despite the same environmental factors (e.g., microgravity, exercise, diet). A follow-up study was conducted to evaluate 5 polymorphisms of enzymes in the one-carbon pathway, and to evaluate how these relate to vision and other ophthalmic changes after flight. Preliminary evaluations of the genetic data indicate that all of the crewmembers with the MTRR GG genotype had vision issues to one degree or another. However, not everyone who had vision issues had this genetic polymorphism, so the situation is more complex than the involvement of this single polymorphism. Metabolomic and further data analyses are underway to clarify these findings, but the preliminary assessments are promising.

Smith, Scott M.↗
NASA NTRS2015

Genetically Engineered Cyanobacteria

The disclosed embodiments provide cyanobacteria spp. that have been genetically engineered to have increased production of carbon-based products of interest. These genetically engineered hosts efficiently convert carbon dioxide and light into carbon-based products of interest such as long chained hydrocarbons. Several constructs containing polynucleotides encoding enzymes active in the metabolic pathways of cyanobacteria are disclosed. In many instances, the cyanobacteria strains have been further genetically modified to optimize production of the carbon-based products of interest. The optimization includes both up-regulation and down-regulation of particular genes.

Zhou, Ruanbao↗
NASA NTRS2017

Developing Model Benchtop Systems for Microbial Experimental Evolution

Understanding how microbes impact an ecosystem has improved through advances of molecular and genetic tools, but creating complex systems that emulate natural biology goes beyond current technology. In fact, many chemical, biological, and metabolic pathways of even model organisms are still poorly characterized. Even then, standard laboratory techniques for testing microbial impact on environmental change can have many drawbacks; they are time-consuming, labor intensive, and are at risk of contamination. By having an automated process, many of these problems can be reduced or even eliminated. We are developing a benchtop system that can run for long periods of time without the need for human intervention, involve multiple environmental stressors at once, perform real-time adjustments of stressor exposure based on current state of the population, and minimize contamination risks. Our prototype device allows operators to generate an analogue of real world micro-scale ecosystems that can be used to model the effects of disruptive environmental change on microbial ecosystems. It comprises of electronics, mechatronics, and fluidics based systems to control, measure, and evaluate the before and after state of microbial cultures from exposure to environmental stressors. Currently, it uses four parallel growth chambers to perform tests on liquid cultures. To measure the population state, optical sensors (LED/photodiode) are used. Its primary selection pressure is UV-C radiation, a well-studied stressor known for its cell- and DNA-damaging effects and as a mutagen. Future work will involve improving the current growth chambers, as well as implementing additional sensors and environmental stressors into the system. Full integration of multiple culture testing will allow inter-culture comparisons. Besides the temperature and OD sensors, other types of sensors can be integrated such as conductivity, biomass, pH, and dissolved gasses such as CO and O. Additional environmental stressor systems like temperature (extreme heat or cold), metal toxicity, and other forms of radiation will increase the scale and testing range.

Developing↗
NASA NTRS2017

Electrochemical Detection of the Molecules of Life

All forms of life on Earth contain cellular machinery that can transform and regulate chemical energy through metabolic pathways. These processes are oxidation-reduction reactions that are performed by four key classes of molecules: flavins, nicotinamaides, porphyrins, and quinones. By detecting the electrochemical interaction of these redox-active molecules with an electrode, a method of differentiating them by their class could be established and incorporated into future life-detecting missions. This body of work investigates the electrochemistry of ubiquitous molecules found in life and how they may be detected. Molecules can oxidise or reduce the surface of an electrode - giving or receiving electrons - and these interactions are represented by changes in current with respect to an applied voltage. This relationship varies with: electrolyte type and concentration, working electrode material, the redox-active molecule itself, and scan rate. Flavin adenine dinucleotide (FAD), riboflavin, nicotinamide adenine dinucleotide (NADH), and anthraquinone are all molecules found intracellularly in almost all living organisms. An organism-synthesised extracellular redox-active molecule, Plumbagin, was also selected as part of this study. The goal of this work is to detect these molecules in seawater and assess its application in searching for life on Ocean Worlds.

astrobiolog↗
NASA NTRSDate not supplied

Developing A Miniaturized Biology Assay for the Astrobiology Search Kit

Partnering with Retego Labs we will develop an acetate assay to use in the Astrobiology Search Kit advanced spectrometer. Our current knowledge of metabolic pathways (methanogeneis, and acetogenesis) both produce acetate. There is no known method of producing acetate abiotically, therefore the detection of acetate indicates the presence of biology. There is no current assays to directly detect acetate. We would be developing the first assay. Our development plan is based on the development of previous assays. We start with EPA standards then modify and increase the sensitivity based on our detection needs. In this case the detection is 10^2 cells/ml equivalent. This assay would be useful on Titan where if life exists the biogeochemistry is methane based instead of water based like Earth (possibly Mars, Europa).

H. Smith↗
NASA NTRS2021

Mitigation and Use of Biofilms in Space for the Benefit of Human Space Exploration

Biofilms are groups of cells of the same or different species living in communities. Such structures are usually attached to surfaces, and on Earth, they have been found in diverse and extreme environments. Such agglomerations have been described as recalcitrant or protective when facing adversity. In space systems, biofilms have been found on a multitude of hardware surfaces. Different studies have identified genetic changes that may impact human health. The insufficiency of consistent research may return inconclusive arguments as to what extent microgravity encourages virulence and how biofilms could exacerbate crewed spaceflight–especially ones to remote areas with a lack of resupply and service missions. However, biofilms are also beneficial to plant biology, and they may supply in metabolic pathways that produce useful organic and inorganic components to maintain life in other celestial bodies. There are expansive areas of research that look into biofilms in space and scientific recommendations that reflect on expanding the aerospace industry’s knowledge of biofilms, how to mitigate, or use them to the advantage of spaceflight.

Yo-ann Velez Justiniano↗
NASA NTRSDate not supplied

B Complex 5-Methyltetrahydrofolate, Riboflavin, Pyridoxine, and Methylcobalamin Supplementation as a Non-Mechanical Countermeasure to Mitigate Optic Disc Edema Changes During Strict 6º Head-Down Tilt Bed Rest

A subset of astronauts on International Space Station missions have experienced optic disc edema, part of what is characterized as Spaceflight Associated Neuro-ocular Syndrome (SANS). While the precise cause of SANS is unknown, it is likely that there are multiple contributing factors, including genetic and environmental factors. Our recent work has shown that crewmembers with SANS have higher concentrations of metabolic biomarkers of impairments in the one-carbon metabolic pathway compared to unaffected astronauts - before, during, and after f light (1). B-vitamin status and the presence of one-carbon pathway single nucleotide polymorphism (SNP) variants predicted the incidence of SANS pathologies, including optic disc edema (2). Specifically, the G allele of methionine synthase reductase (MTRR) A66G and the C allele of serine hydroxymethyltransferase-1 (SHMT1) C1420T were associated with increased incidence of SANS pathologies (2). In a recent 30-d bed rest head-down tilt study with 0.5% CO2 exposure, 5 of 11 subjects developed optic disc edema (4) and the same SHMT1 C1420T and MTRR A66G genetic variants were associated with a larger increase in total retina thickness, a quantitative measure of optic disc edema (5). We published a multi-hit hypothesis of how genetics represents an indispensable element of SANS, which is a multifactorial problem (6). In brief: endothelial dysfunction secondary to genetic, biochemical/nutritional, and physiological (e.g., cardiovascular/fluid shift) f actors could lead to optic disc edema and the other ocular changes that occur in SANS. We expanded this hypothesis to include the possibility that genetic effects on B-vitamin status can alter nitric oxide synthesis and oxidative stress in the endothelium. This in turn could alter the turnover of structural components of the sclera, making it more susceptible to pathologic changes when faced with stressors related to the unrelenting headward fluid shift that occurs in weightlessness and strict head-down tilt bed rest (5). If the relationships that we have observed in flight and ground-based research hold true for the SANS Countermeasure Study, these genetic factors could predict who will be more susceptible to the development of SANS, and more importantly could also provide countermeasure options. As has been shown extensively in the literature, vitamin supplementation can serve to overcome genetic hindrances to one-carbon biochemistry and vascular physiology. Thus, based on our findings, publications, and hypotheses, supported by extensive supporting literature, we had hoped to test in the SANS Countermeasure Study the efficacy of a bioactive B-vitamin complex as a countermeasure to optimize function of the one-carbon pathway and prevent or mitigate optic disc edema during strict 6-degree head down tilt bed rest, and ultimately in space f light. While the supplement is no longer planned to be tested in the SANS Countermeasure Study because of laws regulating supplementation studies like this costing much more than initially planned, we will assess the contribution of one-carbon pathway genetics and B-vitamin status to SANS risk.

S R Zwart↗
NASA NTRS2022

Evaluating Mineral Lattices as Evolutionary Proxies for Metalloprotein Evolution

Protein coordinated iron-sulfur clusters drive electron flow within metabolic pathways for organisms throughout the tree of life. It is not known how iron-sulfur clusters were first incorporated into proteins. Structural analogies to iron-sulfde minerals present on early Earth, suggest a connection in the evolution of both proteins and minerals. The availability of large protein and mineral crystallographic structure data sets, provides an opportunity to explore co-evolution of proteins and minerals on a large-scale using informatics approaches. However, quantitative comparisons are confounded by the infnite, repeating nature of the mineral lattice, in contrast to metal clusters in proteins, which are fnite in size. We address this problem using the Niggli reduction to transform a mineral lattice to a fnite, unique structure that when translated reproduces the crystal lattice. Protein and reduced mineral structures were represented as quotient graphs with the edges and nodes corresponding to bonds and atoms, respectively. We developed a graph theory-based method to calculate the maximum common connected edge subgraph (MCCES) between mineral and protein quotient graphs. MCCES can accommodate differences in structural volumes and easily allows additional chemical criteria to be considered when calculating similarity. To account for graph size differences, we use the Tversky similarity index. Using consistent criteria, we found little similarity between putative ancient iron-sulfur protein clusters and iron-sulfur mineral lattices, suggesting these metal sites are not as evolutionarily connected as once thought. We discuss possible evolutionary implications of these findings in addition to suggesting an alternative proxy, mineral surfaces, for better understanding the coevolution of the geosphere and biosphere

Kenneth N. McGuinness↗
NASA NTRS2019

De novo design of symmetric ferredoxins that shuttle electrons in vivo

A symmetric origin for bacterial ferredoxins was first proposed over 50 y ago, yet, to date, no functional symmetric molecule has been constructed. It is hypothesized that extant proteins have drifted from their symmetric roots via gene duplication followed by mutations. Phylogenetic analyses of extant ferredoxins support the independent evolution of N- and C-terminal sequences, thereby allowing consensus-based design of symmetric 4Fe-4S molecules. All designs bind two [4Fe-4S] clusters and exhibit strongly reducing midpoint potentials ranging from −405 to −515 mV. One of these constructs efficiently shuttles electrons through a designed metabolic pathway in Escherichia coli. These finding establish that ferredoxins consisting of a symmetric core can be used as a platform to design novel electron transfer carriers for in vivo applications. Outer-shell asymmetry increases sequence space without compromising electron transfer functionality.

Andrew C. Mutter↗
NASA NTRS2021

Biophysical Characterization of Iron-Sulfur Proteins

Iron-sulfur proteins are primordial catalysts and biological electron carriers that today drive major metabolic pathways across all forms of life. They can access a diversity of oxidation states and can mediate electron transfer over an extended range of reduction potentials spanning more than 1 V. Depending on the protein micro-environment and geometry of ligand, co-ordination the iron-sulfur clusters can occur in different forms [2Fe-2S], [3Fe-4S], HiPIP [4Fe-4S], and [4Fe-4S]. There are several spectroscopic methods available to characterize the composition and electronic configuration of the iron-sulfur clusters, such as optical methods and electron paramagnetic resonance. This paper presents the protocols used to characterize the metal center of Coiled-Coil Iron-Sulfur (CCIS), an artificial metalloprotein containing one [4Fe-4S] cluster. It is expected that these protocols will be of general utility for other iron-sulfur proteins.

Iron-sulfur proteins↗
DOE OSTI2020

Microbial electro-photosynthesis

Methods and apparatus for growing photosynthetic organisms lacking Photosystem II (PSII) function using externally supplied electrons shuttled into the organism using redox mediators to improve photosynthetic output and to produce and recover chemicals of interest. By removing PSII, all PAR photons are funneled toward Photosystem I, thereby significantly increasing the theoretical photon utilization efficiency for CO2 fixation, energy storage and the capacity to synthesize valuable chemicals. Additional genetic modification can be performed to insert or enhance specific metabolic pathways to generate products of commercial interest.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Enzyme scaffolds and methods of use

Polypeptide scaffolds comprising enzymatic proteins are provided. The enzymatic polypeptide scaffolds comprise heterologous enzymes to form a heterologous metabolic pathway, and can be targeted to a substrate through a surface anchoring domain. The enzymatic polypeptide scaffolds leverage the high specificity and affinity protein/protein interaction between the cohesins and dockerins of microorganismal cellulosomes to form custom enzymatic arrays.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

BETO 2021 Peer Review - Cell Free and Immobilization Technologies (CFIT)

Today, several key factors negatively impact the production of fuels and chemicals from renewable sources. Common hindrances in the biological production of biochemicals are: (1) end-product or intermediate toxicity to the microbial biocatalyst, (2) the diversion of carbon to biomass formation, and (3) co-production of undesired byproducts. A particularly attractive alternative is to eliminate the biocatalyst entirely and instead operate the desired metabolic pathways in isolation, thus circumventing the roadblocks of biological toxicity, lower yields, and lack of specificity. However, cell-free enzyme systems still suffer from low productivities owing in part to the effects of free diffusion of intermediates, lack of long term enzyme stability, cofactor cost or inefficient recycling rates, and finally, the cost of enzyme production/purification. This project represents a new effort to propose innovative and cost competitive routes to producing biochemicals from a variety of feedstocks using cell free approaches. These routes will help reduce the current risk and cost associated with classical cell free production. Cell free technologies show promise for application to the production of toxic/inhibitory products or products difficult to separate from microbial growth media and can help reduce the production barriers in multiple areas of biological conversion of feedstocks to biochemicals.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2023

Biochemical Process Modeling and Simulation (BPMS)

The Biochemical Process Modeling and Simulation project aims to reduce the cost and time of research by applying theory, modeling, and simulation to the most relevant bottlenecks in the biochemical process. We use molecular modeling, quantum mechanics, metabolic modeling, fluid dynamics, and reaction-diffusion methods in close collaboration with pretreatment, hydrolysis, upgrading, and TEA. The project's outcomes are increased yields and efficiency of the biochemical process, added value to products, and reduced price of fuels by specifically targeting catalytic efficiency, reactor design, enzyme efficiency, and microbial design. We work closely with experimental projects to identify problems and iterate with experiments to find and refine solutions. By working with experimentalists, we decide on problems that can be solved with simulation that could otherwise not be solved or would take too long with experiment alone to reach BETO's targets. Over the years, we have produced solutions that have resulted in determining the most likely fatty-acid derivative for passive transport out of bacteria that upgrade biomass, and we have also designed enzyme mutations for enhanced lignin upgrading. Metabolic models have been developed to tune the activity of 2,3 butanediol production for the 2030 target. A computational method to deliver understanding of how complex omics data can be interpreted in the metabolic pathways of organisms used in the Agile Biofoundry. We have found methods to overcome specific barriers and continue to develop those methods. Our reactor studies have guided the design of both the microbes and reactors for aerobic and micro-aerobic production at all scales and have been instrumental in improving the accuracy of techno-economic analysis models. This project is essential in the process of selecting the final processes for 2030 SAF production targets. More specifically, recently, we have: 1) Predicted the strength of the basic structural interactions in commodity plastics to provide guidance for plastics upcycling strategies. 2) Developed computational tool to improve the characterization of lignin-derived compounds 3) Developed new methodologies to enable Machine Learning-based Directed Evolution for protein engineering. 4) Developed Machine Learning methods to predict protein promiscuity and mutations to further improve microbial and enzymatic driven processes and demonstrated the utility of ML approaches to engineering proteins from sparse experimental datasets. 5) Developed new methods to enable high-fidelity simulation of aerobic fermentation at industrial scale and resolving mismatch of time scales through subcycling/operator splitting 7) Identified the difficulty in preventing local high-oxygen conditions in industrial bubble columns, which leads to less-desirable acetoin production, suggesting future research directions in alternative reactor configurations (e.g loop reactors, shallow-channel reactors).

BIOMASS FUELS↗
DOE OSTI2023

A Synthetic Transcription Factor and Core Promoter System in Picochlorum renovo Enables Tunable Gene Expression

Picochlorum renovo is a recently characterized microalga of industrial interest. Its rapid growth rate, and high temperature and salinity tolerances make P. renovo an attractive candidate for industrial scale cultivation and downstream production of sustainable fuels and chemicals. Currently, genetic tools for many non-model microalgae are limited and would greatly benefit from an orthogonal gene expression system to bypass host regulation. Additionally, the engineering of complex metabolic pathways in eukaryotic organisms to optimize growth or biosynthesize high value products often requires tunable expression of each gene in a pathway. Here we explore a tunable orthogonal gene expression system using a synthetic transcription factor (sTF) and core promoters (CPs) conferring expression of the fluorescent protein mCherry to quantify protein expression. The sTF paired with the relevant binding site (BS) led to an ~5X increase in reporter gene expression compared to the native RuBisCo promoter, however had limited tunability with increasing BS number. Quantification of mCherry expression under 34 different CPs paired with the sTF and BS showed an order of magnitude of expression tunability. Future work with this system will entail generation of an overexpression library via random integration of the relevant BS in an sTF expressing P. renovo strain. With this sTF and CP system we aim to greatly improve growth rates and product titers in photosynthetic organisms, while also providing a potentially universal gene expression system for microalgae.

algae↗