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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Effect of dietary vitamin E or selenium on prostaglandin dehydrogenase in hyperoxic rat lung

Weanling male rats were fed semipurified diets supplemented with 0, 60, or 600 IU/kg vitamin E or 0, 100, or 1000 ppb selenium. One group was injected daily with vitamin E at a rate equivalent to consumption of 60 IU/kg. Animals from all groups were sacrificed after exposure to normobaric oxygen or air for 48 h. Lung tissue was analyzed for the combined activity of prostaglandin dehydrogenase and reductase. Using the decline in enzyme activity as an indicator of susceptibility to oxygen poisoning, protection against hyperoxia was directly related to the level of vitamin E supplementation. Selenium supplemented at 100 ppb provided significant protection when compared to 0 ppb or 1000 ppb. The latter dose may have been marginally toxic. Thus dietary supplementation of vitamin E and selenium may influence the relative susceptibility of an animal to pulmonary oxygen poisoning.

North, L. N.↗
NASA NTRS1995

Connective tissue integrity is lost in vitamin B-6-deficient chicks

The objective of the present investigation was to characterize further the connective tissue disorder produced by pyridoxine (vitamin B-6) deficiency, as previously evidenced by electron microscopy. Following the second post-natal week, fast growing male chicks were deprived of pyridoxine for a 1-mo period. Six weeks post-natally, blood concentrations in the experimental deficiency group had declined to deficiency levels as registered by low concentrations of pyridoxal phosphate (coenzyme form) in erythrocytes, but did not reach levels associated with neurological symptoms. Light microscopic study showed abnormalities in the extracellular matrix of the connective tissues. Collagen cross-links and the aldehyde contents were not significantly lower in cartilage and tendon collagens of vitamin B-6-deficient animals than in age-matched controls; also, their proteoglycan degrading protease and collagenase activities measured in articular cartilages were not greater. Thus, proteolysis was an unlikely alternative mechanism to account for the loss of connective tissue integrity. These results point to the need for further investigation into adhesive properties of collagen associated proteoglycans or other proteins in vitamin B-6-deficient connective tissue.

Non-NASA Center↗
NASA NTRS1992

Decreased heterotopic osteogenesis in vitamin-D-deficient, but normocalcemic guinea pigs

The effect of vitamin D deficiency unhampered by hypocalcemia on de novo bone formation was studied in guinea pigs. Heterotopic induction of osteogenesis was evaluated 4 weeks after intramuscular transplantation of allogenic urinary bladder transitional epithelium from vitamin-D-repleted (+D) donors into +D and -D recipients. In -D recipients the frequency of osteogenesis and the amount of induced bone were significantly diminished; induced bone was less mature, scantly cellular woven bone poorly repopulated with bone marrow. No effect of vitamin D deficiency on orthotopic bone growth and on mineralization of orthotopic and heterotopically induced bone was observed. It is proposed that in addition to inducing factors (BMPs, growth factors) which may be responsible for transformation of mesenchymal cells to osteoprogenitor cells, normal concentrations of 1,25-(OH)2D3 may be required for proliferation and further differentiation of these cells into osteoblasts and for expression of genes engaged in extracellular matrix formation and maturation.

NASA Discipline Musculoskeletal↗
DOE OSTI2023

Vitamin interdependencies predicted by metagenomics-informed network analyses and validated in microbial community microcosms

Abstract Metagenomic or metabarcoding data are often used to predict microbial interactions in complex communities, but these predictions are rarely explored experimentally. Here, we use an organism abundance correlation network to investigate factors that control community organization in mine tailings-derived laboratory microbial consortia grown under dozens of conditions. The network is overlaid with metagenomic information about functional capacities to generate testable hypotheses. We develop a metric to predict the importance of each node within its local network environments relative to correlated vitamin auxotrophs, and predict that a Variovorax species is a hub as an important source of thiamine. Quantification of thiamine during the growth of Variovorax in minimal media show high levels of thiamine production, up to 100 mg/L. A few of the correlated thiamine auxotrophs are predicted to produce pantothenate, which we show is required for growth of Variovorax , supporting that a subset of vitamin-dependent interactions are mutualistic. A Cryptococcus yeast produces the B-vitamin pantothenate, and co-culturing with Variovorax leads to a 90-130-fold fitness increase for both organisms. Our study demonstrates the predictive power of metagenome-informed, microbial consortia-based network analyses for identifying microbial interactions that underpin the structure and functioning of microbial communities.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

4'-Deoxypyridoxine disrupts vitamin B 6 homeostasis in Escherichia coli K12 through combined inhibition of cumulative B 6 uptake and PLP-dependent enzyme activity

Pyridoxal 5'-phosphate (PLP) is the active form of vitamin B 6 and a cofactor for many essential metabolic processes such as amino acid biosynthesis and one carbon metabolism. 4’-deoxypyridoxine (4dPN) is a long known B 6 antimetabolite but its mechanism of action was not totally clear. By exploring different conditions in which PLP metabolism is affected in the model organism Escherichia coli K12, we showed that 4dPN cannot be used as a source of vitamin B 6 as previously claimed and that it is toxic in several conditions where vitamin B 6 homeostasis is affected, such as in a B 6 auxotroph or in a mutant lacking the recently discovered PLP homeostasis gene, yggS . In addition, we found that 4dPN sensitivity is likely the result of multiple modes of toxicity, including inhibition of PLP-dependent enzyme activity by 4’-deoxypyridoxine phosphate (4dPNP) and inhibition of cumulative pyridoxine (PN) uptake. These toxicities are largely dependent on the phosphorylation of 4dPN by pyridoxal kinase (PdxK).

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1996

Vitamin D endocrine system after short-term space flight

The exposure of the body to microgravity during space flight causes a series of well-documented changes in Ca(2+) metabolism, yet the cellular/molecular mechanisms leading to these changes are poorly understood. There is some evidence for microgravity-induced alterations in the vitamin D endocrine system, which is known to be primarily involved in the regulation of Ca(2+) metabolism. Vitamin D-dependent Ca(2+) binding proteins, or calbindins, are believed to have a significant role in maintaining cellular Ca(2+) homeostasis. We used immunocytochemical, biochemical and molecular approaches to analyze the expression of calbindin-D(sub 28k) and calbindin-D(sub 9k) in kidneys and intestines of rats flown for 9 days aboard the Spacelab 3 mission. The effects of microgravity on calbindins in rats in space vs. 'grounded' animals (synchronous Animal Enclosure Module controls and tail suspension controls) were compared. Exposure to microgravity resulted in a significant decrease in calbindin-D(sub 28k) content in kidneys and calbindin-D(sub 9k) in the intestine of flight and suspended animals, as measured by enzyme-linked immunosorbent assay (ELISA). Immunocytochemistry (ICC) in combination with quantitative computer image analysis was used to measure in situ the expression of calbindins in kidneys and intestine, and insulin in pancreas. There was a large decrease in the distal tubular cell-associated calbindin-D(sub 28k) and absorptive cell-associated calbindin-D(sub 9k) immunoreactivity in the space and suspension kidneys and intestine, as compared with matched ground controls. No consistent differences in pancreatic insulin immunoreactivity between space, suspension and ground controls was observed. There were significant correlations between results by quantitative ICC and ELISA. Western blot analysis showed no consistent changes in the low levels of intestinal and renal vitamin D receptors. These findings suggest that a decreased expression of calbindins after a short-term exposure to microgravity and modelled weightlessness, may affect cellular Ca(2+) homeostasis and contribute to Ca(2+) and bone metabolism disorders induced by space flight.

Rhoten, William B.↗
NASA NTRS1997

Anabolic Vitamin D Analogs as Countermeasures to Bone Loss

We demonstrated for the first time that vitamin D3 influences the effect of PTH on bone cell calcium ion levels. This is a rapid effect, taking place within seconds/minutes. This may prove to be a critical contribution to our understanding of bone physiology in that these two hormones are among the most potent regulators of bone calcium content and of systemic calcium homeostasis. Together with the data gathered from the study of astronauts exposed to microgravity for extended periods, these observations suggest the interaction of vitamin D3 and PTH as a possible therapeutic target in the treatment of bone loss disorders such as osteoporosis and disuse atrophy. Chronic exposure of cultured osteoblasts to vitamin D, altered the number of voltage-sensitive Ca(+2) channels expressed. Estrogen treatment yielded a similar result, suggesting that there is overlap in the mechanism by which these hormones elicit long-term effects on bone cell calcium homeostasis.

Li, Wei↗
NASA NTRS2004

High Salt Intake Promotes Urinary Loss of Vitamin D Metabolites by Dahl Salt-Sensitive Rats in a Space Flight Model

Vitamin D metabolism in the Dahl salt-sensitive (S) rat, a model of salt-induced hypertension, differs from that in the Dahl salt-resistant (R) rat. We have demonstrated that female S rats are more vulnerable than female R rats to decreases in plasma 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) concentrations during hind limb unloading (a space flight model). We report here on the response of the vitamin D endocrine system of S and R rats to hind limb unloading during high salt intake. Dahl female rats (9.7-week-old) were tail-suspended (hind limb unloaded) for 28 days, while fed a diet containing twice the salt in standard rat chow (2 % sodium chloride). Control rats were fed the same diet, but were not hind limb unloaded. Vitamin D metabolites were analyzed by HPLC and radioimmunoassay kits from Diasorin.

Thierry-Palmer, M.↗
DOE OSTI2025

Vitamin-Mediated Glucose Flow Cell for Sustainable Power Generation

Glucose as biofuel asserts unique advantages, including low-temperature electricity generation, easy accessibility, low storage cost, and flexible application for on-demand power generation. Riboflavin, also known as Vitamin B 2 , is a critical component in biological systems and is involved in many metabolic reactions as enzyme cofactors. Inspired by these metabolic reactions, we demonstrate a flow cell for electrochemical glucose oxidation reaction (GOR), using riboflavin as an environmentally friendly mediator to replace traditional noble metal catalysts. When paired with O 2 under alkaline conditions, the glucose flow cell achieves a peak power density of 13 mW/cm 2 , 20 times higher than the previous report in alkaline conditions. The demonstrated vitamin-mediated engineered biofuel flow cell delivered high peak power density at room temperature/ambient pressure while maintaining low cost and environmental friendliness, eliminating the need for a noble metal catalyst.

electrolytes↗
DOE OSTI2021

Targeting a cell surface vitamin D receptor on tumor-associated macrophages in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive tumor with limited treatment options and poor prognosis. We applied the in vivo phage display technology to isolate peptides homing to the immunosuppressive cellular microenvironment of TNBC as a strategy for non-malignant target discovery. We identified a cyclic peptide (CSSTRESAC) that specifically binds to a vitamin D receptor, protein disulfide-isomerase A3 (PDIA3) expressed on the cell surface of tumor-associated macrophages (TAM), and targets breast cancer in syngeneic TNBC, non-TNBC xenograft, and transgenic mouse models. Systemic administration of CSSTRESAC to TNBC-bearing mice shifted the cytokine profile toward an antitumor immune response and delayed tumor growth. Moreover, CSSTRESAC enabled ligand-directed theranostic delivery to tumors and a mathematical model confirmed our experimental findings. Finally, in silico analysis showed PDIA3-expressing TAM in TNBC patients. This work uncovers a functional interplay between a cell surface vitamin D receptor in TAM and antitumor immune response that could be therapeutically exploited.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1974

Tibial bone mineral distribution as influenced by calcium, phosphorus, and vitamin D feeding levels in the growing turkey

Roentgen signs, subperiosteal, endosteal, and trabecular bone growth are evaluated in turkeys fed phosphorus at the 0.5, 0.56, 0.68, 0.90, and 2.70 percent levels. Calcium levels of 0.30, 0.40, 0.60, 1.2, and 3.60 percent were also tested. Vitamin D levels of 0, 100, 300, 900 and 27,000 I.U. per day were likewise evaluated. Roentgen signs, bone mineral as measured by T-125 gamma ray absorption, and bone mineral growth patterns as shown by radiograph area projection are correlated with calcium, phosphorus, and vitamin D feeding levels. Differences in bone growth at the various feeding levels were observed which were not reflected by differences in other studied parameters.

Spurrell, F. A.↗
NASA NTRS1978

Experiment requirements: Vitamin D metabolites and bone demineralization, Spacelab 2, experiment no. 1

As a contribution toward an understanding of the molecular basis of bone loss, mineral imbalance, and increasing fecal calcium under conditions of prolonged space flight, the blood levels of biologically active vitamin D metabolites of flight crew members will be quantitatively measured. Prior to the mission, the refinement of existing and the development of new techniques for the assay of all vitamin D metabolites will provide an arsenal of methods suitable for a wide range of metabolite levels. In terms of practical application, the analysis of human and animal plasma samples, Spacelab crew plasma samples, and flight hardware are envisioned.

Schnoes, H. K.↗
NASA NTRS1985

The Role of Vitamin D in the Bone Changes Associated with Simulated Weightlessness

The role of vitamin D in the change in bone metabolism was examined. The serum concentrations in rats sacrificed after 2, 5, 7, 10, 12 and 15 days of suspension was measured. Between days 1 and 5 of suspension and then gradually decreased towards normal between days 5 and 15. The time course of the changes in the circulating concentrations of 1,25(OH)2D and 24,25(OH)2D mirror almost precisely the changes in bone metabolism. The relationship between the changes in vitamin D metabolism and bone metabolism is investigated. Whether the bone changes are due to the change in serum concentration of 1,25(OH)2D or the changes in bone formation causing a reduction in Ca flux out of the serum pool and thereby suppressing 1,25(OH)2D production is examined. It is found that suspension had no effect on hormone concentration in the 1,25(OH)2D infused animals. Nevertheless, both vehicle and 1,25(OH)2D infused suspended rats exhibited the same reduction in bone mineral, and uptake of (45)Ca. It is suggested that the transitory reduction in circulating 1,25(OH)2D during suspension is not likely to cause the abnormalities in bone metabolism but rather that the changes in bone metabolism are primary and cause the fall in serum 1,25(OH)2D concentration. This supports the hypothesis that the metabolic abnormalities in bone associated with simulated weightlessness are due to the direct effect of unweighting on the bone.

Halloran, B. P.↗
NASA NTRS1988

Vitamin D metabolites and bioactive parathyroid hormone levels during Spacelab 2

The effect of an 8-day space flight (Spacelab mission 2) on plasma levels of the vitamin D and parathyroid hormones is investigated experimentally in four crew members. The results are presented in tables and graphs and briefly characterized. Parathyroid hormone levels remained normal throughout the flight, whereas vitamin D hormone levels increased significantly on day 1 but returned to normal by day 7.

Morey-Holton, Emily R.↗
NASA NTRS2002

Vector-averaged gravity-induced changes in cell signaling and vitamin D receptor activity in MG-63 cells are reversed by a 1,25-(OH)2D3 analog, EB1089

Skeletal unloading in an animal hindlimb suspension model and microgravity experienced by astronauts or as a result of prolonged bed rest causes site-specific losses in bone mineral density of 1%-2% per month. This is accompanied by reductions in circulating levels of 1,25-(OH)(2)D(3), the active metabolite of vitamin D. 1,25-(OH)(2)D(3), the ligand for the vitamin D receptor (VDR), is important for calcium absorption and plays a role in differentiation of osteoblasts and osteoclasts. To examine the responses of cells to activators of the VDR in a simulated microgravity environment, we used slow-turning lateral vessels (STLVs) in a rotating cell culture system. We found that, similar to cells grown in microgravity, MG-63 cells grown in the STLVs produce less osteocalcin, alkaline phosphatase, and collagen Ialpha1 mRNA and are less responsive to 1,25-(OH)(2)D(3). In addition, expression of VDR was reduced. Moreover, growth in the STLV caused activation of the stress-activated protein kinase pathway (SAPK), a kinase that inhibits VDR activity. In contrast, the 1,25-(OH)(2)D(3) analog, EB1089, was able to compensate for some of the STLV-associated responses by reducing SAPK activity, elevating VDR levels, and increasing expression of osteocalcin and alkaline phosphatase. These studies suggest that, not only does simulated microgravity reduce differentiation of MG-63 cells, but the activity of the VDR, an important regulator of bone metabolism, is reduced. Use of potent, less calcemic analogs of 1,25-(OH)(2)D(3) may aid in overcoming this defect. Copyright 2002 Elsevier Science Inc.

Foton Project↗
DOE OSTI2024

Soil microbial community response to corrinoids is shaped by a natural reservoir of vitamin B12

Abstract Soil microbial communities perform critical ecosystem services through the collective metabolic activities of numerous individual organisms. Most microbes use corrinoids, a structurally diverse family of cofactors related to vitamin B12. Corrinoid structure influences the growth of individual microbes, yet how these growth responses scale to the community level remains unknown. Analysis of metagenome-assembled genomes suggests that corrinoids are supplied to the community by members of the archaeal and bacterial phyla Thermoproteota, Actinobacteria, and Proteobacteria. Corrinoids were found largely adhered to the soil matrix in a grassland soil, at levels exceeding those required by cultured bacteria. Enrichment cultures and soil microcosms seeded with different corrinoids showed distinct shifts in bacterial community composition, supporting the hypothesis that corrinoid structure can shape communities. Environmental context influenced both community- and taxon-specific responses to specific corrinoids. These results implicate corrinoids as key determinants of soil microbiome structure and suggest that environmental micronutrient reservoirs promote community stability.

58 GEOSCIENCES↗
DOE OSTI2022

Astronauts Plasma-Derived Exosomes Induced Aberrant EZH2-Mediated H3K27me3 Epigenetic Regulation of the Vitamin D Receptor

There are unique stressors in the spaceflight environment. Exposure to such stressors may be associated with adverse effects on astronauts' health, including increased cancer and cardiovascular disease risks. Small extracellular vesicles (sEVs, i.e., exosomes) play a vital role in intercellular communication and regulate various biological processes contributing to their role in disease pathogenesis. To assess whether spaceflight alters sEVs transcriptome profile, sEVs were isolated from the blood plasma of 3 astronauts at two different time points: 10 days before launch (L-10) and 3 days after return (R+3) from the Shuttle mission. AC16 cells (human cardiomyocyte cell line) were treated with L-10 and R+3 astronauts-derived exosomes for 24 h. Total RNA was isolated and analyzed for gene expression profiling using Affymetrix microarrays. Enrichment analysis was performed using Enrichr. Furthermore, transcription factor (TF) enrichment analysis using the ENCODE/ChEA Consensus TF database identified gene sets related to the polycomb repressive complex 2 (PRC2) and Vitamin D receptor (VDR) in AC16 cells treated with R+3 compared to cells treated with L-10 astronauts-derived exosomes. Further analysis of the histone modifications using datasets from the Roadmap Epigenomics Project confirmed enrichment in gene sets related to the H3K27me3 repressive mark. Interestingly, analysis of previously published H3K27me3–chromatin immunoprecipitation sequencing (ChIP-Seq) ENCODE datasets showed enrichment of H3K27me3 in the VDR promoter. Collectively, our results suggest that astronaut-derived sEVs may epigenetically repress the expression of the VDR in human adult cardiomyocytes by promoting the activation of the PRC2 complex and H3K27me3 levels.

59 BASIC BIOLOGICAL SCIENCES↗