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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
DOE OSTI2025

Transcriptomic and metabolomic analysis of recalcitrant phosphorus solubilization mechanisms in Trametes gibbosa

Introduction Phosphorus (P) is a crucial growth-limiting nutrient in soil, much of which remains challenging for plants to absorb and use. Unlike chemical phosphate fertilizers, phosphate-solubilizing microorganisms (PSMs) offer a means to address available phosphorus deficiency without causing environmental harm. PSMs possess multiple mechanisms for phosphorus solubilization. Although the phosphorus-solubilizing mechanisms of phosphate-solubilizing bacteria (PSB) have been well characterized, the mechanisms utilized by phosphate-solubilizing fungi (PSF) remain largely unexplored. Methods This study isolated a PSF strain, Trametes gibbosa T-41, from soil and evaluated its phosphorus solubilizing capacity with organic (calcium phytin; Phytin-P) and inorganic (tricalcium phosphate; Ca-P) phosphorus sources. The phosphorus solubilization, enzyme activity, and organic acid production of T-41 were measured. And the P-solubilizing mechanism conducted by transcriptomic and metabolomic analyses. Results and discussion T-41 exhibited varying phosphorus solubilizing capacity when grown with organic (calcium phytin; Phytin-P) and inorganic (tricalcium phosphate; Ca-P) phosphorus sources (109.80 ± 8.9 mg/L vs. 57.5 ± 7.9 mg/L, p < 0.05). Compared with the Ca-P treatment, T-41 demonstrated a stronger alkaline phosphatase (ALP) production capacity under Phytin-P treatment (34.5 ± 1.2 μmol/L/h vs. 19.8 ± 0.8 μmol/L/h, p < 0.05). Meanwhile, the production of oxalic acid, maleic acid, and succinic acid was higher under Phytin-P treatment ( p < 0.05). Transcriptomic and metabolomic analysis revealed that different phosphorus sources altered metabolic pathways such as galactose metabolism, glyoxylate and dicarboxylic acid metabolism, and ascorbate and aldolate metabolism. Key metabolites like myo-inositol, 2-oxoglutarate, and pyruvate were found to impact the performance of T. gibbosa T-41 differently under the two P sources. Notably, synthesis in Ca-P vs. Pytin-P, T-41 upregulated genes involved in myo-inositol synthesis, potentially enhancing its P-solubilizing ability. These results provide new insights into the molecular mechanisms of PSF at the transcriptomic and metabolomic levels, laying a theoretical foundation for the broader application of PSF as bio-phosphorus fertilizers in the future.

Chen, Yulan↗
DOE OSTI2021

Impacts of Initial Ca/P on Amorphous Calcium Phosphate

Amorphous calcium phosphate (ACP) is a metastable phase in the crystallization pathway of calcium phosphates. Understanding its chemical and structural properties could provide critical insights into biomineralization mechanisms. Of particular interest is the impact of the initial Ca/P on the structure of ACP. Further, the influence of Ca/P on the size, precipitate chemistry, and transformation of ACP is crucial to understanding the metastability of amorphous phosphates. In situ pair distribution function (PDF) analysis results 5 min after mixing show that the Ca-P bonding geometry varies from predominantly monodentate, to mixed monodentate and bidentate, to predominantly bidentate as Ca/P increases from 0.2 to 5.0. This relationship is consistent across a pH range of 6-11. Samples with only monodentate Ca-P geometries transform directly to hydroxylapatite, while samples some or all bidentate geometries form brushite. Regardless of the initial ratio, the Ca/P of precipitates is close to 1.0. In situ small-angle X-ray scattering shows particle size increases with increasing Ca/P. This is the first evidence of structural variations in ACP and is directly linked to system chemistry. Finally, synthesis of ACP with monodentate Ca-P geometries is a promising method to control the crystallization pathway to form hydroxylapatite at circumneutral pH without stabilizing ions.

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

X-ray Spectroscopic Quantification of Phosphorus Transformation in Saharan Dust during Trans-Atlantic Dust Transport

Saharan dust is an important phosphorus (P) supply to remote and oligotrophic parts of the oceans and American lowland tropical rainforests. Phosphorus speciation in aeolian dust ultimately controls the release and bioavailability of P after dust deposition, but the speciation in Saharan dust and its change during the trans-Atlantic transport remains unclear. Here, using P K-edge X-ray absorption near edge structure (XANES) spectroscopy, we showed that with increasing dust traveling distance from the Sahara Desert to Cape Verde and to Puerto Rico, about 570 and 4000 km, respectively, the proportion of Ca-bound P (Ca-P), including both apatite and non-apatite forms, decreased from 68–73% to 50–71% and to 21–37%. The changes were accompanied by increased iron/aluminum-bound P proportion from 14–25% to 23–46% and to 44–73%, correspondingly. Laboratory simulation experiments suggest that the changes in P speciation can be ascribed to increasing degrees of particle sorting and atmospheric acidification during dust transport. The presence of relatively soluble non-apatite Ca-P in the Cape Verde dust but not in the Puerto Rico dust is consistent with the higher P water solubility of the former than the latter. Our findings provide insights into the controls of atmospheric processes on P speciation, solubility, and stability in Saharan dust.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1999

Reactions and Surface Transformations of a Bone-Bioactive Material in a Simulated Microgravity Environment

A comprehensive program to investigate the expeditious in vitro formation of three-dimensional bone-like tissue is currently underway at the University of Pennsylvania. The study reported here forms a part of that program. Three-dimensional bone-like tissue structures may be grown under the simulated microgravity conditions of NASA designed Rotating Wall Bioreactor Vessels (RWV's). Such tissue growth will have wide clinical applications. In addition, an understanding of the fundamental changes that occur to bone cells under simulated microgravity would yield important information that will help in preventing or minimizing astronaut bone loss, a major health issue with travel or stay in space over long periods of time. The growth of three-dimensional bone-like tissue structures in RWV's is facilitated by the use of microcarriers which provide structural support. If the microcarrier material additionally promotes bone cell growth, then it is particularly advantageous to employ such microcarriers. We have found that reactive, bone-bioactive glass (BBG) is an attractive candidate for use as microcarrier material. Specifically, it has been found that BBG containing Ca- and P- oxides upregulates osteoprogenitor cells to osteoblasts. This effect on cells is preceded by BBG reactions in solution which result in the formation of a Ca-P surface layer. This surface further transforms to a bone-like mineral (i.e., carbonated crystalline hydroxyapatite (c-HA)). At normal gravity, time-dependent, immersion-induced BBG reactions and transformations are greatly affected both by variations in the composition of the milieu in which the glass is immersed and on the immersion conditions. However, the nature of BBG reactions and phase transformations under the simulated microgravity conditions of RWV's are unknown, and must be understood in order to successfully use BBG as microcarrier material in RWV'S. In this paper, we report some of our recent findings in this regard using experimental and numerical methods. BBG composition 45S5, the most reactive among known bone-bioactive glasses, was chosen for the study. BBG 45S5 behavior in physiological solutions was tested in simulated microgravity and compared with that at normal gravity. On the basis of our numerical study, we have chosen the BBG granule size to be in the range 40-70 microns, and a RWV rotational speed of 10 rpm. Our numerical study has shown that these parameters enable the microcarrier to remain suspended in the medium without experiencing collisions with the wall of the vessel. Immersion-induced changes in the solution composition and the material surface were analyzed after immersion.

Radin, S.↗
NASA NTRS2003

The Effect of Simulated Microgravity Environment of RWV Bioreactors on Surface Reactions and Adsorption of Serum Proteins on Bone-bioactive Microcarriers

Biomimetically modified bioactive materials with bone-like surface properties are attractive candidates for use as microcarriers for 3-D bone-like tissue engineering under simulated microgravity conditions of NASA designed rotating wall vessel (RWV) bioreactors. The simulated microgravity environment is attainable under suitable parametric conditions of the RWV bioreactors. Ca-P containing bioactive glass (BG), whose stimulatory effect on bone cell function had been previously demonstrated, was used in the present study. BG surface modification via reactions in solution, resulting formation of bone-like minerals at the surface and adsorption of serum proteins is critical for obtaining the stimulatory effect. In this paper, we report on the major effects of simulated microgravity conditions of the RWV on the BG reactions surface reactions and protein adsorption in physiological solutions. Control tests at normal gravity were conducted at static and dynamic conditions. The study revealed that simulated microgravity remarkably enhanced reactions involved in the BG surface modification, including BG dissolution, formation of bone-like minerals at the surface and adsorption of serum proteins. Simultaneously, numerical models were developed to simulate the mass transport of chemical species to and from the BG surface under normal gravity and simulated microgravity conditions. The numerical results showed an excellent agreement with the experimental data at both testing conditions.

Radin, Shula↗
DOE OSTI2020

Materials Data on CaP by Materials Project

CaP is alpha boron-derived structured and crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six P2- atoms. There are two shorter (2.96 Å) and four longer (3.00 Å) Ca–P bond lengths. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six P2- atoms. There are four shorter (2.89 Å) and two longer (2.93 Å) Ca–P bond lengths. There are two inequivalent P2- sites. In the first P2- site, P2- is bonded in a 7-coordinate geometry to six Ca2+ and one P2- atom. The P–P bond length is 2.25 Å. In the second P2- site, P2- is bonded in a 7-coordinate geometry to six Ca2+ and one P2- atom. The P–P bond length is 2.31 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca5P8 by Materials Project

Ca5P8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six P+1.25- atoms to form CaP6 octahedra that share corners with four equivalent CaP6 octahedra, corners with two equivalent PP4 tetrahedra, edges with ten CaP6 octahedra, and edges with two equivalent PP4 tetrahedra. The corner-sharing octahedral tilt angles are 8°. There are four shorter (2.89 Å) and two longer (3.13 Å) Ca–P bond lengths. In the second Ca2+ site, Ca2+ is bonded to six P+1.25- atoms to form CaP6 octahedra that share corners with four equivalent CaP6 octahedra, corners with two equivalent PP4 tetrahedra, edges with ten CaP6 octahedra, and edges with two equivalent PP4 tetrahedra. The corner-sharing octahedral tilt angles are 9°. There are a spread of Ca–P bond distances ranging from 2.90–3.04 Å. In the third Ca2+ site, Ca2+ is bonded to six P+1.25- atoms to form CaP6 octahedra that share corners with six CaP6 octahedra, corners with six equivalent PP4 tetrahedra, and edges with nine CaP6 octahedra. The corner-sharing octahedra tilt angles range from 8–9°. There are four shorter (2.95 Å) and two longer (2.97 Å) Ca–P bond lengths. There are three inequivalent P+1.25- sites. In the first P+1.25- site, P+1.25- is bonded to five Ca2+ and one P+1.25- atom to form PCa5P octahedra that share corners with seven PCa5P octahedra, a cornercorner with one PP4 tetrahedra, and edges with ten PCa5P octahedra. The corner-sharing octahedra tilt angles range from 0–94°. The P–P bond length is 2.16 Å. In the second P+1.25- site, P+1.25- is bonded to five Ca2+ and one P+1.25- atom to form PCa5P octahedra that share corners with seven PCa5P octahedra, a cornercorner with one PP4 tetrahedra, and edges with ten PCa5P octahedra. The corner-sharing octahedra tilt angles range from 0–94°. The P–P bond length is 2.18 Å. In the third P+1.25- site, P+1.25- is bonded to four P+1.25- atoms to form distorted PP4 tetrahedra that share corners with three PCa5P octahedra, corners with nine CaP6 octahedra, and edges with three CaP6 octahedra. The corner-sharing octahedra tilt angles range from 21–76°. The P–P bond length is 2.34 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaP3 by Materials Project

CaP3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight P+0.67- atoms. There are a spread of Ca–P bond distances ranging from 2.91–3.27 Å. There are three inequivalent P+0.67- sites. In the first P+0.67- site, P+0.67- is bonded to three equivalent Ca2+ and two P+0.67- atoms to form distorted PCa3P2 trigonal bipyramids that share corners with five equivalent PCaP3 tetrahedra, corners with two equivalent PCa3P2 trigonal bipyramids, and edges with two equivalent PCa3P2 trigonal bipyramids. There are one shorter (2.19 Å) and one longer (2.24 Å) P–P bond lengths. In the second P+0.67- site, P+0.67- is bonded to one Ca2+ and three P+0.67- atoms to form distorted corner-sharing PCaP3 tetrahedra. There are one shorter (2.21 Å) and one longer (2.26 Å) P–P bond lengths. In the third P+0.67- site, P+0.67- is bonded in a 6-coordinate geometry to four equivalent Ca2+ and two P+0.67- atoms. The P–P bond length is 2.23 Å.

36 MATERIALS SCIENCE↗