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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
DOE OSTI2017

Spatial mapping and profiling of metabolite distributions during germination

Germination is a highly complex process by which seeds begin to develop and establish themselves as viable organisms. In this paper, we utilize a combination of GC-MS, LC-fluorescence, and mass spectrometry imaging (MSI) approaches to profile and visualize the metabolic distributions of germinating seeds from two different inbreds of maize seeds, B73 and Mo17. GC and LC analyses demonstrate that the two inbreds are highly differentiated in their metabolite profiles throughout the course of germination, especially with regard to amino acids, sugar alcohols, and small organic acids. Crude dissection of the seed followed by GC-MS analysis of polar metabolites also revealed that many compounds were highly sequestered among the various seed tissue types. To further localize compounds, matrix-assisted laser desorption/ionization MSI is utilized to visualize compounds in fine detail in their native environments over the course of germination. Most notably, the fatty acyl chain-dependent differential localization of phospholipids and TAGs were observed within the embryo and radicle, showing correlation with the heterogeneous distribution of fatty acids. Furthermore, other interesting observations include unusual localization of ceramides on the endosperm/scutellum boundary, and subcellular localization of ferulate in the aleurone.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Bacillus anthracis spores germinate extracellularly at air-liquid interface in an in vitro lung model under serum-free conditions

Aims: To better understand the parameters that govern spore dissemination after lung exposure using in vitro cell systems. Methods and Results: We evaluated the kinetics of uptake, germination and proliferation of B. anthracis Sterne spores in association with human primary lung epithelial cells, Calu-3, and A549 cell lines. We also analyzed the influence of various cell culture media formulations related to spore germination. Conclusions: We found negligible spore uptake by epithelial cells, but germination and proliferation of spores in the extracellular environment was evident, and was appreciably higher in A549 and Calu-3 cultures than in primary epithelial cells. Additionally, our results revealed spores in association with primary cells submerged in cell culture media germinated 1 h

Powell, Joshua D.↗
DOE OSTI2017

How Germinal Centers Evolve Broadly Neutralizing Antibodies: the Breadth of the Follicular Helper T Cell Response

Many HIV-1-infected patients evolve broadly neutralizing antibodies (bnAbs). This evolutionary process typically takes several years and is poorly understood as selection taking place in germinal centers occurs on the basis of antibody affinity. B cells with the highest-affinity receptors tend to acquire the most antigen from the follicular dendritic cell (FDC) network and present the highest density of cognate peptides to follicular helper T (Tfh) cells, which provide survival signals to the B cell. bnAbs are therefore expected to evolve only when the B cell lineage evolving breadth is consistently capturing and presenting more peptides to Tfh cells than other lineages of more specific B cells. Here we develop mathematical models of Tfh cells in germinal centers to explicitly define the mechanisms of selection in this complex evolutionary process. Our results suggest that broadly reactive B cells presenting a high density of peptides bound to major histocompatibility complex class II molecules (pMHC) are readily outcompeted by B cells responding to lineages of HIV-1 that transiently dominate the within host viral population. Conversely, if broadly reactive B cells acquire a large variety of several HIV-1 proteins from the FDC network and present a high diversity of several pMHC, they can be rescued by a large fraction of the Tfh cell repertoire in the germinal center. Under such circumstances the evolution of bnAbs is much more consistent. Increasing either the magnitude of the Tfh cell response or the breadth of the Tfh cell repertoire markedly facilitates the evolution of bnAbs. Because both the magnitude and breadth can be increased by vaccination with several HIV-1 proteins, this calls for experimental testing. Many HIV-infected patients slowly evolve antibodies that can neutralize a large variety of viruses. Such broadly neutralizing antibodies (bnAbs) could in the future become therapeutic agents. bnAbs appear very late, and patients are typically not protected by them. At the moment, we fail to understand why this takes so long and how the immune system selects for broadly neutralizing capacity. Typically, antibodies are selected based on affinity and not on breadth. We developed mathematical models to study two different mechanisms by which the immune system can select for broadly neutralizing capacity. One of these is based upon the repertoire of different follicular helper T (Tfh) cells in germinal centers. In conclusion, we suggest that broadly reactive B cells may interact with a larger fraction of this repertoire and demonstrate that this would select for bnAbs. Intriguingly, this suggests that broadening the Tfh cell repertoire by vaccination may speed up the evolution of bnAbs.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2002

Anaerobic conditions improve germination of a gibberellic acid deficient rice

Dwarf plants are useful in research because multiple plants can be grown in a small area. Rice (Oryza sativa L.) is especially important since its relatively simple genome has recently been sequenced. We are characterizing a gibberellic acid (GA) mutant of rice (japonica cv 'Shiokari,' line N-71) that is extremely dwarf (20 cm tall). Unfortunately, this GA mutation is associated with poor germination (70%) under aerobic conditions. Neither exogenous GA nor a dormancy-breaking heat treatment improved germination. However, 95% germination was achieved by germinating the seeds anaerobically, either in a pure N2 environment or submerged in unstirred tap water. The anaerobic conditions appear to break a mild post-harvest dormancy in this rice cultivar. Copyright 2002 Crop Science Society of America.

Non-NASA Center↗
NASA NTRS1991

Gene activity during germination of spores of the fern, Onoclea sensibilis: RNA and protein synthesis and the role of stored mRNA

Pattern of 3H-uridine incorporation into RNA of spores of Onoclea sensibilis imbibed in complete darkness (non-germinating conditions) and induced to germinate in red light was followed by oligo-dT cellulose chromatography, gel electrophoresis coupled with fluorography and autoradiography. In dark-imbibed spores, RNA synthesis was initiated about 24 h after sowing, with most of the label accumulating in the high mol. wt. poly(A) -RNA fraction. There was no incorporation of the label into poly(A) +RNA until 48 h after sowing. In contrast, photo-induced spores began to synthesize all fractions of RNA within 12 h after sowing and by 24 h, incorporation of 3H-uridine into RNA of irradiated spores was nearly 70-fold higher than that into dark-imbibed spores. Protein synthesis, as monitored by 3H-arginine incorporation into the acid-insoluble fraction and by autoradiography, was initiated in spores within 1-2 h after sowing under both conditions. Autoradiographic experiments also showed that onset of protein synthesis in the cytoplasm of the germinating spore is independent of the transport of newly synthesized nuclear RNA. One-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis of 35S-methionine-labelled proteins revealed a good correspondence between proteins synthesized in a cell-free translation system directed by poly(A) +RNA of dormant spores and those synthesized in vivo by dark-imbibed and photo-induced spores. These results indicate that stored mRNAs of O. sensibilis spores are functionally competent and provide templates for the synthesis of proteins during dark-imbibition and germination.

NASA Discipline Number 29-20↗
NASA NTRS2017

Zinnia Germination and Lunar Soil Amendment

Germination testing was performed to determine the best method for germinating zinnias. This method will be used to attempt to germinate the zinnia seeds produced in space. It was found that seed shape may be critically important in determining whether a seed will germinate or not. The ability of compost and worm castings to remediate lunar regolith simulant for plant growth was tested. It was found that neither treatment effectively improves plant growth in lunar regolith simulant. A potential method of improving lunar regolith simulant by mixing it with arcillite was discovered.

Reese, Laura↗
DOE OSTI2021

A prion-like protein regulator of seed germination undergoes hydration-dependent phase separation

Many organisms evolved strategies to survive desiccation. Plant seeds protect dehydrated embryos from various stressors and can lay dormant for millennia. Hydration is the key trigger to initiate germination, but the mechanism by which seeds sense water remains unresolved. Here we identified an uncharacterized Arabidopsis thaliana prion-like protein we named FLOE1, which phase separates upon hydration and allows the embryo to sense water stress. We demonstrate that biophysical states of FLOE1 condensates modulate its biological function in vivo in suppressing seed germination under unfavorable environments. We find intragenic, intraspecific, and interspecific natural variation in FLOE1 expression and phase separation and show that intragenic variation is associated with adaptive germination strategies in natural populations. This combination of molecular, organismal, and ecological studies uncovers FLOE1 as a tunable environmental sensor with direct implications for the design of drought-resistant crops, in the face of climate change.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Switchgrass-associated soil microbes have subtle but distinct effects on germination vs. growth under drought

Soil microbial communities can play a large role in plant fitness, including plants’ response to drought. How microbes mediate drought response may also differ across the plants’ life stage, but studies rarely study causal effects of microbes on plant fitness at multiple stages. We conducted a greenhouse experiment on switchgrass (Panicum virgatum L.) to investigate how microbial presence (sterile bulk vs. live bulk soils) and microbial source (communities from bulk vs. rhizosphere soil) affect germination and seedling growth (life-stage) during drought. We also investigated how drought and life-stage alter the assembly of the inoculated communities. Both drought conditions and the absence of microbes reduced germination (49% and 50% fewer seedlings, respectively, p < 0.05), but there were few effects of microbial presence on older seedlings. In addition, microbial source had no effect on the evaluated plant traits, but interestingly, the initially similar bulk and rhizosphere communities became compositionally distinct after 34 days with germinating seeds, but not with seedlings. Therefore, it may be that the plants did respond to microbial source through changes in seed or root exudates, and calls for further study. Finally, while sometimes microbes did benefit plants under drought, we did not find evidence that they are especially beneficial in this condition. We suggest that microbes’ effects differ across plant life stage, and may be both positive and negative. Further research should advance understanding of plant stress tolerance within a framework of plant-microbiome co-development.

drought↗
DOE OSTI2016

Effect of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings

An investigation of the effects of UV-C radiation and hypergravity on germination, growth and content of chlorophyll of wheat seedlings has been done. The UV-C irradiation periods of exposure were 30, 60, 90, 120 and 180 minutes. The hypergravity used were 1000 g, 2000 g and 2500 g. The combination treatment is UV-C irradiation for 180 min followed by each hypergravity. The results showed that irradiation of UV-C on wheat seeds have stimulated the seed germination, but hypergravity and combination treatments on wheat seeds have inhibited the seed germination. Those treatments gave negative effects to growth rate, the content of chlorophyll a, b and total chlorophyll of wheat seedlings.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Methods to Promote Germination of Dormant Setaria viridis Seeds

Setaria viridis has recently emerged as a promising genetic model system to study diverse aspects of monocot biology. While the post-germination life cycle of S. viridis is approximately 8 weeks long, the prolonged dormancy of freshly harvested seeds can more than double the total time required between successive generations. Here we describe methods that promote seed germination in S. viridis. Our results demonstrate that treating S. viridis seeds with liquid smoke or a GA 3 and KNO 3 solution improves germination rates to 90% or higher even in seeds that are 6 days post-harvest with similar results obtained whether seeds are planted in soil or on gel-based media. Importantly, we show that these treatments have no significant effect on the growth of the adult plant. We have tested these treatments on diverse S. viridis accessions and show variation in their response. The methods described here will help advance research using this model grass species by increasing the pace at which successive generations of plants can be analyzed.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2014

A Simple and Versatile 2-Dimensional Platform to Study Plant Germination and Growth under Controlled Humidity

We describe a simple, inexpensive, but remarkably versatile and controlled growth environment for the observation of plant germination and seedling root growth on a flat, horizontal surface over periods of weeks. The setup provides to each plant a controlled humidity (between 56% and 91% RH), and contact with both nutrients and atmosphere. The flat and horizontal geometry of the surface supporting the roots eliminates the gravitropic bias on their development and facilitates the imaging of the entire root system. Experiments can be setup under sterile conditions and then transferred to a non-sterile environment. The system can be assembled in 1-2 minutes, costs approximately 8.78$\$$ per plant, is almost entirely reusable (0.43$\$$ per experiment in disposables), and is easily scalable to a variety of plants. We demonstrate the performance of the system by germinating, growing, and imaging Wheat (Triticum aestivum), Corn (Zea mays), and Wisconsin Fast Plants (Brassica rapa). Germination rates were close to those expected for optimal conditions.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Non-TZF Protein AtC3H59/ZFWD3 Is Involved in Seed Germination, Seedling Development, and Seed Development, Interacting with PPPDE Family Protein Desi1 in Arabidopsis

Despite increasing reports on the function of CCCH zinc finger proteins in plant development and stress response, the functions and molecular aspects of many non-tandem CCCH zinc finger (non-TZF) proteins remain uncharacterized. AtC3H59/ZFWD3 is an Arabidopsis non-TZF protein and belongs to the ZFWD subfamily harboring a CCCH zinc finger motif and a WD40 domain. In this study, we characterized the biological and molecular functions of AtC3H59, which is subcellularly localized in the nucleus. The seeds of AtC3H59-overexpressing transgenic plants (OXs) germinated faster than those of wild type (WT), whereas atc3h59 mutant seeds germinated slower than WT seeds. AtC3H59 OX seedlings were larger and heavier than WT seedlings, whereas atc3h59 mutant seedlings were smaller and lighter than WT seedlings. Moreover, AtC3H59 OX seedlings had longer primary root length than WT seedlings, whereas atc3h59 mutant seedlings had shorter primary root length than WT seedlings, owing to altered cell division activity in the root meristem. During seed development, AtC3H59 OXs formed larger and heavier seeds than WT. Using yeast two-hybrid screening, we isolated Desi1, a PPPDE family protein, as an interacting partner of AtC3H59. AtC3H59 and Desi1 interacted via their WD40 domain and C-terminal region, respectively, in the nucleus. Taken together, our results indicate that AtC3H59 has pleiotropic effects on seed germination, seedling development, and seed development, and interacts with Desi1 in the nucleus via its entire WD40 domain. To our knowledge, this is the first report to describe the biological functions of the ZFWD protein and Desi1 in Arabidopsis.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1999

A method for the imbibition and germination of wheat seeds in space

A method was developed for the reliable germination in space of wheat seeds on porous tube nutrient delivery systems. Germination paper strips were loosely rolled into cylinders and two seeds inserted close to the outer edges of each cylinder. This configuration: 1) directed the emerging shoots upward and roots downward, 2) was efficient in wicking moisture from the porous tubes, and 3) provided open areas for oxygen diffusion. Cotton tufts were inserted into the bottom crevices of the cylinders to fix the seeds in a mid-level position and cylinders were then storable (indefinitely) prior to the preprogrammed (on-orbit) initiation of imbibition. This method extends both the upper and lower ends of acceptable moisture levels for successful seed germination, increasing the probability of success for spaceflight applications where moisture availability is more variable than on Earth.

NASA Discipline Life Support Systems↗
DOE OSTI2013

Oral administration of drugs with hypersensitivity potential induces germinal center hyperplasia in secondary lymphoid organ/tissue in Brown Norway rats, and this histological lesion is a promising candidate as a predictive biomarker for drug hypersensitivity occurrence in humans

It is important to evaluate the potential of drug hypersensitivity as well as other adverse effects during the preclinical stage of the drug development process, but validated methods are not available yet. In the present study we examined whether it would be possible to develop a new predictive model of drug hypersensitivity using Brown Norway (BN) rats. As representative drugs with hypersensitivity potential in humans, phenytoin (PHT), carbamazepine (CBZ), amoxicillin (AMX), and sulfamethoxazole (SMX) were orally administered to BN rats for 28 days to investigate their effects on these animals by examinations including observation of clinical signs, hematology, determination of serum IgE levels, histology, and flow cytometric analysis. Skin rashes were not observed in any animals treated with these drugs. Increases in the number of circulating inflammatory cells and serum IgE level did not necessarily occur in the animals treated with these drugs. However, histological examination revealed that germinal center hyperplasia was commonly induced in secondary lymphoid organs/tissues in the animals treated with these drugs. In cytometric analysis, changes in proportions of lymphocyte subsets were noted in the spleen of the animals treated with PHT or CBZ during the early period of administration. The results indicated that the potential of drug hypersensitivity was identified in BN rat by performing histological examination of secondary lymphoid organs/tissues. Data obtained herein suggested that drugs with hypersensitivity potential in humans gained immune reactivity in BN rat, and the germinal center hyperplasia induced by administration of these drugs may serve as a predictive biomarker for drug hypersensitivity occurrence. - Highlights: • We tested Brown Norway rats as a candidate model for predicting drug hypersensitivity. • The allergic drugs did not induce skin rash, whereas D-penicillamine did so in the rats. • Some of allergic drugs increased inflammatory cells and IgE, but the others did not. • The allergic drugs commonly induced germinal center hyperplasia in lymphoid tissues. • Some of these allergic drugs transiently increased CD4{sup +}CD25{sup +} T cells in the spleen.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1991

Germination and growth of wheat in simulated Martian atmospheres

One design for a manned Mars base incorporates a bioregenerative life support system based upon growing higher plants at a low atmospheric pressure in a greenhouse on the Martian surface. To determine the concept's feasibility, the germination and initial growth of wheat (Triticum aestivum) was evaluated at low atmospheric pressures in simulated Martian atmosphere (SMA) and in SMA supplemented with oxygen. Total atmospheric pressures ranged from 10 to 1013 mb. No seeds germinated in pure SMA, regardless of atmospheric pressure. In SMA plus oxygen at 60 mb total pressure, germination and growth occurred but were lower than in the earth atmosphere controls.

Schwartzkopf, Steven H.↗
NASA NTRS1992

A study of the effects of micro-gravity on seed germination

This study will identify characteristics of seed germination dependent upon gravity. To accomplish this objective, four different seed types will be germinated in space and then be compared to a control group germinated on Earth. Both the experimental and control groups will be analyzed on the cellular level for the size of cells, structural anomalies, and gravitational effects. The experiment will be conducted in a Get Away Special Canister (GAS Can no. 608) owned by the U.S. Space and Rocket Center and designed for students. The GAS Can will remain in the cargo bay of the Space Shuttle with minimal astronaut interaction.

Klein, Lynn Suzanne↗
NASA NTRS1995

Development of an Automated Seed Sowing and Induced Germination System for Space Flight Application

The successful utilization of higher plants in space flight is likely to require the effective transition of plants through all phases of growth and development. A particularly sensitive and critical stage in this cycle is seed germination. The present inflight capability to manipulate seed from a state of dormancy to germination and the performance of such activity under aseptic conditions is extremely limited. An Automated Sowing Mechanism (ASM) has been designed to address this area of science and technology. The self-contained system is readily compatible with the existing Shuttle middeck locker Plant Growth Unit (PGU) and planned Plant Growth Facility (PGF), presenting an opportunity to extend the experimental capability of these systems. The ASM design encompasses the controlled transition of seed from a dry to hydrated state utilizing solid media substrate as the source of water and nutrient support. System activation has been achieved with both photo and timing mechanisms. Controlled induced germination and development of various plant species has been achieved in ground-based trials. The system is presently being prepared for a KC-135 flight test.

Heyenga, A. G.↗
NASA NTRS1991

Phytochrome-mediated germination and early development in spores of Dryopteris filix-mas L.: phase-specific and non phase-specific inhibition by staurosporine

The alkaloid staurosporine, currently known as the most potent inhibitor of protein kinase C, PKC, was tested for its ability to inhibit phytochrome-mediated spore germination in Dryopteris filix-mas L., evaluated by the induction of chlorophyll synthesis. Approximately half-maximal inhibition was obtained at a concentration of 10(-5) M. This effect of staurosporine was phase-specific and was found during the same period in which the presence of extracellular calcium is necessary for realization of the light signal. Furthermore, the ability of staurosporine to prevent progression of a germinated spore into early gametophyte development, evaluated by the accumulation of chlorophyll, was examined. Again, staurosporine (10(-5) M) significantly diminished chlorophyll accumulation, determined quantitatively in vivo by single-cell measurements, in a non-phase specific way. The fact that the phase-specific inhibitory effect of staurosporine in preventing germination was coincident with the phase-specific requirement of Ca2+ suggests that both Ca2+ and staurosporine affect the same step in the signal-transduction chain. A phosphorylation event catalysed by PKC or any Ca2+ -dependent protein kinase is proposed as the target of staurosporine and Ca2+.

Non-NASA Center↗