Chemical and Genetic Detection Systems for Early Warning of Pond Crashes
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Algal Research
Algal biomass is a proposed feedstock for sustainable production of petroleum displacing commodities. However, production of 10% of US demand for liquid transportation fuel from algae would require a 60–150% increase over current agricultural demand for phosphorus fertilizers. Without efforts to recycle major nutrients, algal biomass production can be expected to catalyze a food versus fuel crisis. We have developed a novel and simple process for efficient liberation of phosphate from algal biomass and have demonstrated recycling at both laboratory and pilot scale, of up to 70% of total cellular phosphate from osmotically-shocked but non-denatured Microchloropsis salina biomass using a range of mild incubation conditions. The phosphate released in this process is bioavailable, can support the same level of algal growth as standard nutrients, and does not contain any growth inhibitory compounds as evidenced by its ability to support multiple sequential cycles of growth and remineralization.
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The following trade study was done to answer the following task from the Sandia JPL Collaboration for Europa Lander Statement of Work: Perform a trade study to assess the feasibility of other sterilization/decontamination methods for reducing forward biological contamination on S/C and assess their suitability for PP applications
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Algal Research
Productivity of algal mass culture can be severely reduced by contaminating organisms. It is, therefore, important to identify contaminants, determine their effect on productivity and, ultimately, develop countermeasures against such contamination. In the present study we utilized microbiome analysis by second-generation sequencing of small subunit rRNA genes to characterize the predator and pathogen burden of open raceway cultures of Nannochloropsis salina. Samples were analyzed from replicate raceways before and after crashes. In one culture cycle, we identified two algivorous species, the rotifer Brachionus and gastrotrich Chaetonotus, the presence of which may have contributed to the loss of algal biomass. In the second culture cycle, the raceways were treated with hypochlorite in an unsuccessful attempt to interdict the crash. Our analyses were shown to be an effective strategy for the identification of the biological contaminants and the characterization of intervention strategies.
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Biotechnology and Bioengineering
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Algal Research
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Algal Research
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RNA Biology
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Proposed for publication in Biotechnology and Bioengineering.
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Biotechniques
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Nucleic Acid Research
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The purpose of this LDRD was to generate data that could be used to populate and thereby reduce the uncertainty in global carbon cycle models. These efforts were focused on developing a system for determining the dissolution rate of biogenic calcite under oceanic pressure and temperature conditions and on carrying out a digital transcriptomic analysis of gene expression in response to changes in pCO2, and the consequent acidification of the growth medium.
Chemometrics and Intelligent Laboratory Systems
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Proposed for publication in Analytical Chemistry.
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This short-term, late-start LDRD examined the effects of nutritional deprivation on the energy harvesting complex in microalgae. While the original experimental plan involved a much more detailed study of temperature and nutrition on the antenna system of a variety of TAG producing algae and their concomitant effects on oil production, time and fiscal constraints limited the scope of the study. This work was a joint effort between research teams at Sandia National Laboratories, New Mexico and California. Preliminary results indicate there is a photosystem response to silica starvation in diatoms that could impact the mechanisms for lipid accumulation.
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Membrane proteins make up a diverse and important subset of proteins for which structural information is limited. In this study, chemical cross-linking and mass spectrometry were used to explore the structure of the G-protein-coupled photoreceptor bovine rhodopsin in the dark-state conformation. All experiments were performed in rod outer segment membranes using amino acid 'handles' in the native protein sequence and thus minimizing perturbations to the native protein structure. Cysteine and lysine residues were covalently cross-linked using commercially available reagents with a range of linker arm lengths. Following chemical digestion of cross-linked protein, cross-linked peptides were identified by accurate mass measurement using liquid chromatography-fourier transform mass spectrometry and an automated data analysis pipeline. Assignments were confirmed and, if necessary, resolved, by tandem MS. The relative reactivity of lysine residues participating in cross-links was evaluated by labeling with NHS-esters. A distinct pattern of cross-link formation within the C-terminal domain, and between loop I and the C-terminal domain, emerged. Theoretical distances based on cross-linking were compared to inter-atomic distances determined from the energy-minimized X-ray crystal structure and Monte Carlo conformational search procedures. In general, the observed cross-links can be explained by re-positioning participating side-chains without significantly altering backbone structure. One exception, between C3 16 and K325, requires backbone motion to bring the reactive atoms into sufficient proximity for cross-linking. Evidence from other studies suggests that residues around K325 for a region of high backbone mobility. These findings show that cross-linking studies can provide insight into the structural dynamics of membrane proteins in their native environment.