Natural Catastrophe Insurance Coverage Remains a Challenge for State Programs (open access)

Natural Catastrophe Insurance Coverage Remains a Challenge for State Programs

A letter report issued by the Government Accountability Office with an abstract that begins "Natural catastrophes can adversely affect U.S. residents and businesses by causing extensive property damage. The 2005 hurricanes and other recent natural disasters have had significant effects on the cost of obtaining insurance against such risks, especially in high-risk areas. As private market insurers have raised their premium rates, an increased number of residents have obtained coverage through state-sponsored natural catastrophe programs. In a previous report, GAO identified public policy goals for government involvement in natural catastrophe insurance and applied those goals to potential changes in the federal government's role. To assist Congress as it considers legislative proposals that would increase the federal role in natural catastrophe insurance coverage, Congress asked us to provide a briefing on (1) the current status of key state natural catastrophe insurance programs, and the extent to which the state programs support public policy goals identified in prior GAO reports; (2) the extent to which proposed changes to federal involvement in natural catastrophe insurance support policy goals identified in prior GAO reports; and (3) how natural catastrophe insurance is provided in selected other countries."
Date: May 17, 2010
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library

Alternations of Structure and Functional Activity of Below Ground Microbial Communities at Elevated Atmospheric Carbon Dioxide

The global atmospheric concentration of CO2 has increased by more than 30percent since the industrial revolution. Although the stimulating effects of elevated CO2 (eCO2) on plant growth and primary productivity have been well studied, its influences on belowground microbial communities are poorly understood and controversial. In this study, we showed a significant change in the structure and functional potential of soil microbial communities at eCO2 in a grassland ecosystem, the BioCON (Biodiversity, CO2 and Nitrogen) experimental site (http://www.biocon.umn.edu/) using a comprehensive functional gene array, GeoChip 3.0, which contains about 28,0000 probes and covers approximately 57,000 gene variants from 292 functional gene families involved in carbon, nitrogen, phosphorus and sulfur cycles as well as other functional processes. GeoChip data indicated that the functional structure of microbial communities was markedly different between ambient CO2 (aCO2) and eCO2 by detrended correspondence analysis (DCA) of all 5001 detected functional gene probes although no significant differences were detected in the overall microbial diversity. A further analysis of 1503 detected functional genes involved in C, N, P, and S cycles showed that a considerable portion (39percent) of them were only detected under either aCO2 (14percent) or eCO2 (25percent), indicating that the functional characteristics of the microbial …
Date: May 17, 2010
Creator: He, Zhili; Xu, Meiying; Deng, Ye; Kang, Sanghoon; Wu, Liyou; Van Nostrand, Joy D. et al.
Object Type: Poster
System: The UNT Digital Library

HuMiChip: Development of a Functional Gene Array for the Study of Human Microbiomes

Microbiomes play very important roles in terms of nutrition, health and disease by interacting with their hosts. Based on sequence data currently available in public domains, we have developed a functional gene array to monitor both organismal and functional gene profiles of normal microbiota in human and mouse hosts, and such an array is called human and mouse microbiota array, HMM-Chip. First, seed sequences were identified from KEGG databases, and used to construct a seed database (seedDB) containing 136 gene families in 19 metabolic pathways closely related to human and mouse microbiomes. Second, a mother database (motherDB) was constructed with 81 genomes of bacterial strains with 54 from gut and 27 from oral environments, and 16 metagenomes, and used for selection of genes and probe design. Gene prediction was performed by Glimmer3 for bacterial genomes, and by the Metagene program for metagenomes. In total, 228,240 and 801,599 genes were identified for bacterial genomes and metagenomes, respectively. Then the motherDB was searched against the seedDB using the HMMer program, and gene sequences in the motherDB that were highly homologous with seed sequences in the seedDB were used for probe design by the CommOligo software. Different degrees of specific probes, including gene-specific, …
Date: May 17, 2010
Creator: Tu, Q.; Deng, Ye; Lin, Lu; Hemme, Chris L.; He, Zhili & Zhou, Jizhong
Object Type: Poster
System: The UNT Digital Library
Development of Extraction Techniques for the Detection of Signature Lipids from Oil (open access)

Development of Extraction Techniques for the Detection of Signature Lipids from Oil

Pure cultures, including Desulfovibrio vulgaris and Methanococcus maripaludus, were combined with model oil samples and oil/diesel mixtures to optimize extraction techniques of signature lipids from oil in support of investigation of microbial communities in oil deposit samples targets for microbial enhanced hydrocarbon recovery. Several techniques were evaluated, including standard phospholipid extraction, ether linked lipid for Archaeal bacterial detection, and high pressure extractiontechniques. Recovery of lipids ranged from 50-80percent as compared to extraction of the pure culture. Extraction efficiency was evaluated by the use of internal standards. Field samples will also be tested for recovery of signature lipids with optimized extraction techniques.
Date: May 17, 2010
Creator: Borglin, Sharon; Geller, Jil; Chakraborty, Romy; Hazen, Terry & Mason, Olivia
Object Type: Report
System: The UNT Digital Library
High Throughput Identification, Purification and Structural Characterization of Water Soluble Protein Complexes in Desulfovibrio vulgaris (open access)

High Throughput Identification, Purification and Structural Characterization of Water Soluble Protein Complexes in Desulfovibrio vulgaris

Our scheme for the tagless purification of water soluble complexes. 10 g of protein from a crude bacterial extract is first fractionated by ammonium sulfate precipitation and then by a series of chromatographic steps: anion exchange (IEX), hydrophobic interaction (HIC), and finally size exclusion (Gel Filtration). Fractions from the last chromatography step are trypsin digested and peptides labeled with iTRAQ reagents to allow multiplexing and quantitation during mass spectrometric analysis. Elution profiles of identified proteins are then subjected to clustering analysis.
Date: May 17, 2010
Creator: Dong,, Ming; Han, Bong-Gyoon; Liu, Hui-Hai; Malik, J.; Geller, Jil; Yang, Li et al.
Object Type: Report
System: The UNT Digital Library
Conservation of Modules but not Phenotype in Bacterial Response to Environmental Stress (open access)

Conservation of Modules but not Phenotype in Bacterial Response to Environmental Stress

Microbes live in changing environments and change their phenotype via gene regulation in response. Although this transcriptional response is important for fitness, very little is known about how it evolves in microbes. We started by asking a number of high-level questions about the evolution of transcriptional phenotype: (1) To what extent is transcriptional response conserved, i.e. do conserved genes respond similarly to the same condition; (2) To what extent are transcriptional modules conserved; and (3) Does there exist a general stress response to a variety of stressors? To illuminate these questions, we analyzed more than 500 microarray experiments across the bacterial domain. We looked for conservation of transcriptional regulation both in close sister species and vastly divergent clades. In addition, we produced and analyzed an extensive in-house compendium of environmental stress data in three metal-reducing bacteria.
Date: May 17, 2010
Creator: Timberlake, Sonia; Joachimiak, Marcin; Joyner, Dominique; Chakraborty, Romy; Baumohl, Jason; Dehal, Paramvir et al.
Object Type: Report
System: The UNT Digital Library
Effects of Nitrate Exposure on the Functional Structure of a Microbial Community in a Uranium-contaminated Aquifer (open access)

Effects of Nitrate Exposure on the Functional Structure of a Microbial Community in a Uranium-contaminated Aquifer

Increasing nitrogen deposition, increasing atmospheric CO2, and decreasing biodiversity are three main environmental changes occurring on a global scale. The BioCON (Biodiversity, CO2, and Nitrogen) ecological experiment site at the University of Minnesota's Cedar Creek Ecosystem Science Reserve started in 1997, to better understand how these changes would affect soil systems. To understand how increasing nitrogen deposition affects the microbial community diversity, heterogeneity, and functional structure impact soil microbial communities, 12 samples were collected from the BioCON plots in which nitrogenous fertilizer was added to simulate the effect of increasing nitrogen deposition and 12 samples from without added fertilizer. DNA from the 24 samples was extracted using a freeze-grind protocol, amplified, labeled with a fluorescent dye, and then hybridized to GeoChip, a functional gene array containing probes for genes involved in N, S and C cycling, metal resistance and organic contaminant degradation. Detrended correspondence analysis (DCA) of all genes detected was performed to analyze microbial community patterns. The first two axes accounted for 23.5percent of the total variation. The samples fell into two major groups: fertilized and non-fertilized, suggesting that nitrogenous fertilizer had a significant impact on soil microbial community structure and diversity. The functional gene numbers detected in fertilized …
Date: May 17, 2010
Creator: Van Nostrand, Joy; Waldron, P.; Wu, W.; Zhou, B.; Wu, Liyou; Deng, Ye et al.
Object Type: Report
System: The UNT Digital Library
GeoChip-based Analysis of Groundwater Microbial Diversity in Norman Landfill (open access)

GeoChip-based Analysis of Groundwater Microbial Diversity in Norman Landfill

The Norman Landfill is a closed municipal solid waste landfill located on an alluvium associated with the Canadian River in Norman, Oklahoma. It has operated as a research site since 1994 because it is typical of many closed landfill sites across the U.S. Leachate from the unlined landfill forms a groundwater plume that extends downgradient approximately 250 m from the landfill toward the Canadian River. To investigate the impact of the landfill leachate on the diversity and functional structure of microbial communities, groundwater samples were taken from eight monitoring wells at a depth of 5m, and analyzed using a comprehensive functional gene array covering about 50,000 genes involved in key microbial processes, such as biogeochemical cycling of C, N, P, and S, and bioremediation of organic contaminants and metals. Wells are located within a transect along a presumed flow path with different distances to the center of the leachate plume. Our analyses showed that microbial communities were obviously impacted by the leachate-component from the landfill. The number of genes detected and microbial diversity indices in the center (LF2B) and its closest (MLS35) wells were significantly less than those detected in other more downgradient wells, while no significant changes were observed …
Date: May 17, 2010
Creator: Lu, Zhenmei; He, Zhili; Parisi, Victoria; Kang, Sanghoon; Deng, Ye; Nostrand, Joy Van et al.
Object Type: Report
System: The UNT Digital Library
Tapered plasma channels to phase-lock accelerating and focusing forces in laser-plasma accelerators (open access)

Tapered plasma channels to phase-lock accelerating and focusing forces in laser-plasma accelerators

Tapered plasma channels are considered for controlling dephasing of a beam with respect to a plasma wave driven by a weakly-relativistic, short-pulse laser. Tapering allows for enhanced energy gain in a single laser plasma accelerator stage. Expressions are derived for the taper, or longitudinal plasma density variation, required to maintain a beam at a constant phase in the longitudinal and/or transverse fields of the plasma wave. In a plasma channel, the phase velocities of the longitudinal and transverse fields differ, and, hence, the required tapering differs. The length over which the tapered plasma density becomes singular is calculated. Linear plasma tapering as well as discontinuous plasma tapering, which moves beams to adjacent plasma wave buckets, are also considered. The energy gain of an accelerated electron in a tapered laser-plasma accelerator is calculated and the laser pulse length to optimize the energy gain is determined.
Date: May 17, 2010
Creator: Rittershofer, W.; Schroeder, C. B.; Esarey, E.; Gruner, F. J. & Leemans, W. P.
Object Type: Article
System: The UNT Digital Library

Taxa-area Relationship (TAR) of Microbial Functional Genes with Long-TGerm Fertilization

Diversity and spatial patterns in plant and animal communities are well documented as a positive-power law of a taxa-area relationship (TAR). At present little is known whether this also applies to soil microbial communities and whether long-term fertilization has an influence on the underlying microbial diversity. To test the effects of long-term fertilization on above-ground botanical diversity and below-ground microbial diversity, a nested sampling approach on Park Grass plots (12d& 11/2c) of Rothamsted Reseach in United Kingdom, both at ~;; pH 5 but with plant diversities of between 42 and 13 respectively were used. GeoChip 3.0, covering approximately 57, 000 gene sequences of 292 gene families involved in nitrogen, carbon, sulfur and phosphorus cycling, metal reduction and resistance, and organic contaminant degradation, was used to determine the gene area relationships for both functional and phylogenetic groups and the relationship to plant diversity. Our analysis indicated that the microbial communities were separated by different plant diversity based on DCA. The soil microbial diversity was in accord with plant diversity. Soil microbial community exhibited different z value with different plant diversity, z = 0.0449 with higher plant diversity and z = 0.0583 with lower plant diversity (P< 0.0001). These results suggest that …
Date: May 17, 2010
Creator: Liang, Yuting; Wu, Liyou; Clark, Ian; Xue, Kai; Van Nostrand, Joy D.; Deng, Ye et al.
Object Type: Poster
System: The UNT Digital Library

Functional Ecological Gene Networks to Reveal the Changes Among Microbial Interactions Under Elevated Carbon Dioxide Conditions

Biodiversity and its responses to environmental changes is a central issue in ecology, and for society. Almost all microbial biodiversity researches focus on species richness and abundance but ignore the interactions among different microbial species/populations. However, determining the interactions and their relationships to environmental changes in microbial communities is a grand challenge, primarily due to the lack of information on the network structure among different microbial species/populations. Here, a novel random matrix theory (RMT)-based conceptual framework for identifying functional ecological gene networks (fEGNs) is developed with the high throughput functional gene array hybridization data from the grassland microbial communities in a long-term FACE (Free Air CO2 Enrichment) experiment. Both fEGNs under elevated CO2 (eCO2) and ambient CO2 (aCO2) possessed general characteristics of many complex systems such as scale-free, small-world, modular and hierarchical. However, the topological structure of the fEGNs is distinctly different between eCO2 and aCO2, suggesting that eCO2 dramatically altered the interactions among different microbial functional groups/populations. In addition, the changes in network structure were significantly correlated with soil carbon and nitrogen dynamics, and plant productivity, indicating the potential importance of network interactions in ecosystem functioning. Elucidating network interactions in microbial communities and their responses to environmental changes are …
Date: May 17, 2010
Creator: Deng, Ye; Zhou, Jizhong; Luo, Feng; He, Zhili; Tu, Qichao & Zhi, Xiaoyang
Object Type: Poster
System: The UNT Digital Library
Comparative Genomics Analysis and Phenotypic Characterization of Shewanella putrefaciens W3-18-1: Anaerobic Respiration, Bacterial Microcompartments, and Lateral Flagella (open access)

Comparative Genomics Analysis and Phenotypic Characterization of Shewanella putrefaciens W3-18-1: Anaerobic Respiration, Bacterial Microcompartments, and Lateral Flagella

Respiratory versatility and psychrophily are the hallmarks of Shewanella. The ability to utilize a wide range of electron acceptors for respiration is due to the large number of c-type cytochrome genes present in the genome of Shewanella strains. More recently the dissimilatory metal reduction of Shewanella species has been extensively and intensively studied for potential applications in the bioremediation of radioactive wastes of groundwater and subsurface environments. Multiple Shewanella genome sequences are now available in the public databases (Fredrickson et al., 2008). Most of the sequenced Shewanella strains were isolated from marine environments and this genus was believed to be of marine origin (Hau and Gralnick, 2007). However, the well-characterized model strain, S. oneidensis MR-1, was isolated from the freshwater lake sediment of Lake Oneida, New York (Myers and Nealson, 1988) and similar bacteria have also been isolated from other freshwater environments (Venkateswaran et al., 1999). Here we comparatively analyzed the genome sequence and physiological characteristics of S. putrefaciens W3-18-1 and S. oneidensis MR-1, isolated from the marine and freshwater lake sediments, respectively. The anaerobic respirations, carbon source utilization, and cell motility have been experimentally investigated. Large scale horizontal gene transfers have been revealed and the genetic divergence between these …
Date: May 17, 2010
Creator: Qiu, D.; Tu, Q.; He, Zhili & Zhou, Jizhong
Object Type: Report
System: The UNT Digital Library
IMPACT-T User Document Version 1.6 (open access)

IMPACT-T User Document Version 1.6

IMPACT-T is a fully three-dimensional program to track relativistic particles taking into account space charge forces and short-range longitudinal and transverse wakenelds. IMPACT-T is one of the few codes used in the photoinjector community that has a parallel implementation, making it very useful for high statistics simulations of beam halos and beam diagnostics. It has a comprehensive set of beamline elements, and furthermore allows arbitrary overlap of their fields, which gives the IMPACT-T a capability to model both the standing wave structure and traveling wave structure. It is also unique in its use of space-charge solvers based on an integrated Green function to efficiently and accurately treat beams with large aspect ratio, and a shifted Green function to efficiently treat image charge effects of a cathode. It is also unique in its inclusion of energy binning in the space-charge calculation to model beams with large energy spread. IMPACT-T has a flexible data structure that allows particles to be stored in containers with common characteristics; for photoinjector simulations the containers represent multiple slices, but in other applications they could correspond, e.g., to particles of different species. Together, all these features make IMPACT-T a powerful and versatile tool for modeling beams in …
Date: May 17, 2010
Creator: Qiang, Ji
Object Type: Report
System: The UNT Digital Library
An Experimental and Theoretical Study on the Ionization Energies of Polyynes (H-(C = C)n-H; n = 1 - 9) (open access)

An Experimental and Theoretical Study on the Ionization Energies of Polyynes (H-(C = C)n-H; n = 1 - 9)

We present a combined experimental and theoretical work on the ionization energies of polyacetylene -- organic molecules considered as important building blocks to form polycyclic aromatic hydrocarbons (PAHs) in the proto planetary nebulae such as of CRL 618. This set of astrophysical data can be utilized with significant confidence in future astrochemical models of photon-dominated regions and also of the proto planetary nebulae CRL 618. We recommend ionization energies of polyacetylenes from diacetylene up to heptaacetylene with an experimental accuracy of +- 0.05 eV: 10.03 eV (diacetylene), 9.45 eV (triacetylene), 9.08 eV (tetraacetylene), 8.75 eV (pentaacetylene), 8.65 eV (hexaacetylene), and 8.50 eV (heptaacetylene); further, ionization energies and with an accuracy of +- 0.1 eV: 8.32 eV (octaacetylene) and 8.24 eV (nonaacetylene) were computed. Implications of these energies to the redox chemistry involved in the multiply charged metal-ion mediated chemistry of hydrocarbon-rich atmospheres of planets and their moons such as Titan are also discussed.
Date: May 17, 2010
Creator: Kaiser, Ralf I.; Sun, Bian Jian; Lin, Hong Mao; Chang, Agnes H. H.; Mebel, Alexander M.; Kostko, Oleg et al.
Object Type: Article
System: The UNT Digital Library
Radionuclide Inventory Distribution Project Data Evaluation and Verification White Paper (open access)

Radionuclide Inventory Distribution Project Data Evaluation and Verification White Paper

Testing of nuclear explosives caused widespread contamination of surface soils on the Nevada Test Site (NTS). Atmospheric tests produced the majority of this contamination. The Radionuclide Inventory and Distribution Program (RIDP) was developed to determine distribution and total inventory of radionuclides in surface soils at the NTS to evaluate areas that may present long-term health hazards. The RIDP achieved this objective with aerial radiological surveys, soil sample results, and in situ gamma spectroscopy. This white paper presents the justification to support the use of RIDP data as a guide for future evaluation and to support closure of Soils Sub-Project sites under the purview of the Federal Facility Agreement and Consent Order. Use of the RIDP data as part of the Data Quality Objective process is expected to provide considerable cost savings and accelerate site closures. The following steps were completed: - Summarize the RIDP data set and evaluate the quality of the data. - Determine the current uses of the RIDP data and cautions associated with its use. - Provide recommendations for enhancing data use through field verification or other methods. The data quality is sufficient to utilize RIDP data during the planning process for site investigation and closure. Project …
Date: May 17, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Revisiting Modes of energy generation in sulfate reducing bacteria (open access)

Revisiting Modes of energy generation in sulfate reducing bacteria

Sulfate reducing bacteria (SRB) play an important role in global sulfur and carbon cycling through their ability to completely mineralize organic matter while respiring sulfate to hydrogen sulfide. They are ubiquitous in anaerobic environments and have the ability to reduce toxic metals like Cr(VI) and U(VI). While SRB have been studied for over three decades, bioenergetic modes of this group of microbes are poorly understood. Desulfovibrio vulgaris strain Hildenborough (DvH) has served as a model SRB over the last decade with the accumulation of transcriptomic, proteomic and metabolic data under a wide variety of stressors. To further investigate the three hypothesized modes of energy generation in this anaerobe we conducted a systematic study involving multiple electron donor and acceptor combinations for growth. DvH was grown at 37oC in a defined medium with (a) lactate + thiosulfate, (b) lactate + sulfite (c) lactate + sulfate, (d) pyruvate + sulfate, (e) H2 + acetate + sulfate, (f) formate + acetate + sulfate, g) formate + sulfate and (h) pyruvate fermentation. Cells were harvested at mid-log phase of growth for all conditions for transcriptomics, when the optical density at 600nm was in the range 0.42-0.5. Initial results indicate that cells grown on lactate …
Date: May 17, 2010
Creator: Joachimiak, Marcin; Chakraborty, Romy; Zhou, Aifen; Fortney, Julian; Geller, Jil; Wall, Judy et al.
Object Type: Report
System: The UNT Digital Library

The Role of the Tetraheme Cytochrome c3 in Desulfovibrio vulgaris Hildenborough Metabolism

The role of tetraheme cytochrome c3 (CycA) in the metabolism of the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough (DvH) was investigated by deletion of the cycA gene using a marker-exchange deletion strategy. A highly abundant periplasmic cytochrome, CycA has the important function of transferring electrons from periplasmic hydrogenases (Hyd, Hyn, Hys) to transmembrane complexes which transport the electrons to the cytoplasm where sulfate is reduced. Previous studies have indicated that during its interaction with periplasmic hydrogenases, CycA is also involved in the reduction of toxic metals. Growth of the cycA mutant strain on lactate as the electron donor and sulfate as the terminal electron acceptor showed that, despite its abundance, CycA is not essential for DvH growth. However, the rate of growth of the mutant strain was significantly lower, and the extent of growth less, than rates and extents of growth of the wild type and complement strains on lactate/sulfate medium. This indicates that a portion of the electrons generated from cytoplasmic lactate oxidation are transported by CycA for energy production, possibly in a hydrogen cycling mechanism employed to generate ATP. Failure of the mutant strain to grow on either formate or H2, with sulfate or sulfite as electron acceptors, further …
Date: May 17, 2010
Creator: Semkiw, Elizabeth; Zane, Grant & Wall, Judy
Object Type: Poster
System: The UNT Digital Library
The Muon Collider (open access)

The Muon Collider

We describe the scientific motivation for a new type of accelerator, the muon collider. This accelerator would permit an energy-frontier scientific program and yet would fit on the site of an existing laboratory. Such a device is quite challenging, and requires a substantial R&D program. After describing the ingredients of the facility, the ongoing R&D activities of the Muon Accelerator Program are discussed. A possible U.S. scenario that could lead to a muon collider at Fermilab is briefly mentioned.
Date: May 17, 2010
Creator: Zisman, Michael S
Object Type: Article
System: The UNT Digital Library

Effects of experimental warming and clipping on metabolic change of microbial community in a US Great Plains tallgrass prairie

While more and more studies are being conducted on the effects of global warming, little is known regarding the response of metabolic change of whole soil microbial communities to this phenomenon. In this study, functional gene changes at the mRNA level were analyzed by our new developed GeoChip 3.0. Soil samples were taken from a long-term climate warming experiment site, which has been conducted for ~;;8 years at the Kessler Farm Field Laboratory, a 137.6-ha farm located in the Central Redbed Plains, in McClain County, Oklahoma. The experiment uses a paired factorial design with warming as the primary factor nested with clipping as a secondary factor. An infrared heater was used to simulate global warming, and clipping was used to mimic mowing hay. Twelve 2m x 2m plots were divided into six pairs of warmed and control plots. The heater generates a constant output of ~;;100 Watts m-2 to approximately 2 oC increase in soil temperature above the ambient plots, which is at the low range of the projected climate warming by IPCC. Soil whole microbial communities? mRNA was extracted, amplified, labeled and hybridized with our GeoChip 3.0, a functional gene array covering genes involved in N, C, P, and …
Date: May 17, 2010
Creator: Xie, Jianping; Liu, Xinxing; Liu, Xueduan; Nostrand, Joy D. Van; Deng, Ye; Wu, Liyou et al.
Object Type: Poster
System: The UNT Digital Library
Genetic Adaptation to Salt Stress in Experimental Evolution of Desulfovibrio vulgaris Hildenborough (open access)

Genetic Adaptation to Salt Stress in Experimental Evolution of Desulfovibrio vulgaris Hildenborough

High salinity is one of the most common environmental stressors. In order to understand how environmental organisms adapt to salty environment, an experiment evolution with sulfate reducing bacteria Desulfovibrio vugaris Hildenborough was conducted. Control lines and salt-stressed lines (6 lines each) grown in minimal medium LS4D or LS4D + 100 mM NaCl were transferred for 1200 generations. The salt tolerance was tested with LS4D supplemented with 250 mM NaCl. Statistical analysis of the growth data suggested that all lines adapted to their evolutionary environment. In addition, the control lines performed better than the ancestor with faster growth rate, higher biomass yield and shorter lag phase under salty environment they did not evolve in. However, the salt-adapted lines performed better than the control lines on measures of growth rate and yield under salty environment, suggesting that the salt?evolved lines acquired mutations specific to having extra salt in LS4D. Growth data and gene transcription data suggested that populations tended to improve till 1000 generations and active mutations tended to be fixed at the stage of 1000 generations. Point mutations and insertion/deletions were identified in isolated colonies from salt-adapted and control lines via whole genome sequencing. Glu, Gln and Ala appears to be …
Date: May 17, 2010
Creator: Zhou, Aifen; Hillesland, Kristina; He, Zhili; Joachimiak, Marcin; Zane, Grant; Dehal, Paramvir et al.
Object Type: Report
System: The UNT Digital Library
Chemical structure of vanadium-based contact formation on n-AlN (open access)

Chemical structure of vanadium-based contact formation on n-AlN

We have investigated the chemical interaction between a Au/V/Al/V layer structure and n-type AlN epilayers using soft x-ray photoemission, x-ray emission spectroscopy, and atomic force microscopy. To understand the complex processes involved in this multicomponent system, we have studied the interface before and after a rapid thermal annealing step. We find the formation of a number of chemical phases at the interface, including VN, metallic vanadium, aluminum oxide, and metallic gold. An interaction mechanism for metal contact formation on the entire n-(Al,Ga)N system is proposed.
Date: May 17, 2010
Creator: Pookpanratana, S.; France, R.; Blum, M.; Bell, A.; Bar, M.; Weinhardt, L. et al.
Object Type: Article
System: The UNT Digital Library
Microbial community changes during sustained Cr(VI) reduction at the 100H site in Hanford, WA (open access)

Microbial community changes during sustained Cr(VI) reduction at the 100H site in Hanford, WA

Hexavalent Chromium is a widespread contaminant found in soil, sediment, and groundwater. In order to stimulate microbially-mediated reduction of Cr(VI), a poly-lactate compound (HRC) was injected into the Chromium-contaminated aquifer at the Hanford (WA) 100H site in 2004. Cr(VI) concentrations rapidly declined to below the detection limit and remained so for more than three years after injection. Based on the results of the bacterial community composition using high-density DNA 16S rRNA gene microarrays, we observed the community to transition through denitrifying, ironreducing and sulfate-reducing populations. As a result, we specifically focused isolation efforts on three bacterial species that were significant components of the community. Positive enrichments in defined anaerobic media resulted in the isolation of an iron-reducing Geobacter metallireducens-like isolate, a sulfate-reducing Desulfovibrio vukgaris-like strain and a nitrate-reducing Pseudomonas stutzeri-like isolate among several others. All of these isolates were capable of reducing Cr(VI) anoxically and have been submitted for genome sequencing to JGI. To further characterize the microbial, and geochemical mechanisms associated with in situ Cr(VI) reduction at the site, additional HRC was injected in 2008. The goal was to restimulate the indigenous microbial community and to regenerate the reducing conditions necessary for continued Cr(VI) bio-immobilization in the groundwater. Analysis …
Date: May 17, 2010
Creator: Chakraborty, Romy; Brodie, Eoin L; Faybishenko, Boris; Piceno, Yvette M; Tom, Lauren; Choudhuri, Swati et al.
Object Type: Report
System: The UNT Digital Library
Development of a Model, Metal-reducing Microbial Community for a System Biology Level Assessment of Desulfovibrio vulgaris as part of a Community (open access)

Development of a Model, Metal-reducing Microbial Community for a System Biology Level Assessment of Desulfovibrio vulgaris as part of a Community

One of the largest experimental gaps is between the simplicity of pure cultures and the complexity of open environmental systems, particularly in metal-contaminated areas. These microbial communities form ecosystem foundations, drive biogeochemical processes, and are relevant for biotechnology and bioremediation. A model, metal-reducing microbial community was constructed as either syntrophic or competitive to study microbial cell to cell interactions, cell signaling and competition for resources. The microbial community was comprised of the metal-reducing Desulfovibrio vulgaris Hildenborough and Geobacter sulfurreducens PCA. Additionally, Methanococcus maripaludis S2 was added to study complete carbon reduction and maintain a low hydrogen partial pressure for syntrophism to occur. Further, considerable work has been published on D. vulgaris and the D. vulgaris/ Mc. maripaludis co-culture both with and without stress. We are extending this work by conducting the same stress conditions on the model community. Additionally, this comprehensive investigation includes physiological and metabolic analyses as well as specially designed mRNA microarrays with the genes for all three organisms on one slide so as to follow gene expression changes in the various cultivation conditions as well as being comparable to the co- and individual cultures. Further, state-of -the-art comprehensive AMT tag proteomics allows for these comparisons at the …
Date: May 17, 2010
Creator: Elias, Dwayne; Schadt, Christopher; Miller, Lance; Phelps, Tommy; Brown, S. D.; Arkin, Adam et al.
Object Type: Report
System: The UNT Digital Library
Adaptation of the Biolog Phenotype MicroArrayTM Technology to Profile the Obligate Anaerobe Geobacter metallireducens (open access)

Adaptation of the Biolog Phenotype MicroArrayTM Technology to Profile the Obligate Anaerobe Geobacter metallireducens

The Biolog OmniLog? Phenotype MicroArray (PM) plate technology was successfully adapted to generate a select phenotypic profile of the strict anaerobe Geobacter metallireducens (G.m.). The profile generated for G.m. provides insight into the chemical sensitivity of the organism as well as some of its metabolic capabilities when grown with a basal medium containing acetate and Fe(III). The PM technology was developed for aerobic organisms. The reduction of a tetrazolium dye by the test organism represents metabolic activity on the array which is detected and measured by the OmniLog(R) system. We have previously adapted the technology for the anaerobic sulfate reducing bacterium Desulfovibrio vulgaris. In this work, we have taken the technology a step further by adapting it for the iron reducing obligate anaerobe Geobacter metallireducens. In an osmotic stress microarray it was determined that the organism has higher sensitivity to impermeable solutes 3-6percent KCl and 2-5percent NaNO3 that result in osmotic stress by osmosis to the cell than to permeable non-ionic solutes represented by 5-20percent ethylene glycol and 2-3percent urea. The osmotic stress microarray also includes an array of osmoprotectants and precursor molecules that were screened to identify substrates that would provide osmotic protection to NaCl stress. None of the …
Date: May 17, 2010
Creator: Joyner, Dominique; Fortney, Julian; Chakraborty, Romy & Hazen, Terry
Object Type: Report
System: The UNT Digital Library