Tungsten is Essential for Long-Term Maintenance of Members of Candidate Archaeal Genus Aigarchaeota Group 4

Aigarchaeota, a deeply branching archaeal lineage with no cultivated representatives, is found in geothermal and hydrothermal systems worldwide and consists of at least 9 genus-level groups, each predicted to have diverse metabolic capabilities. This candidate archaeal phylum is part of the TACK superphylum, members of which possess eukaryotic-signature proteins, thus suggesting that they may represent evolutionary steps along the way to the genesis of the first eukaryotic cells. Cultivating members of Aigarchaeota would elucidate how eukaryotes arose in evolutionary history and provide biotechnological applications. Aigarchaeota Group 4 (AigG4), one genus in Aigarchaeota, was previously found to be abundant in corn stover in situ enrichments in Great Boiling Spring (GBS). AigG4 has been maintained in mixed laboratory cultures, where it composes ~ 0.5-1% of the community. However, these cultures could only be maintained when GBS water, which contains ~300 nM tungsten, was included in the medium. In addition, AigG4 metagenome bins from the in situ enrichments and laboratory cultures contained multiple genes encoding putative tungsten-containing aldehyde:ferredoxin oxidoreductases (TAORs). These observations led to the hypothesis that tungsten was the key component in GBS water that allowed for growth of AigG4. The requirement of tungsten for AigG4 long-term maintenance in mixed culture was tested using three different approaches: (1) Assessing the phylogeny of tungsten transporters and TAORs across the Aigarchaeota lineage, followed by confirmation of transcription of hypothesized AigG4 tungsten-associated genes in lab cultures, (2) Measuring tungsten levels in Great Boiling Spring (GBS) using ICP-OES (Inductively coupled plasma-optical emission spectroscopy), and (3) determining minimum amount of tungsten for long-term AigG4 maintenance in corn stover and in a defined mix of sugars (1% glucose, 1% xylose, 1% D-arabinose, 1% L-arabinose, 1% mannose). In addition, FISH (Fluorescent in situ hybridization) probes were designed to target the AigG4 lineage in the hopes that in conjunction with nanometer-scale secondary ion mass spectroscopy (Nano-SIMS), this would test whether tungsten has indirect or direct effects on AigG4 to track carbon substrate intake. Most Aigarchaeota lineages possess a tungsten transporter complex (TTC). AigG4 TTC groups most closely with the Tup family while other Aigarchaeota group with the Wtp family. Group 4 and Group 5 Aigarchaeota contained TAORs that grouped to other hypothesized TAORs but not to characterized counterparts suggesting diverse functional capabilities. Group 4 and Group 5 TAORs clustered together suggesting that these are conserved within these lineages. Gene expression of predicted AigG4 tungsten-associated enzymes was detected in culture. Tungsten was detected in GBS water as previously observed in 2005. In both corn stover and sugar mix, 1 nM tungsten was sufficient for long term AigG4 maintenance. In corn stover, AigG4 decreased to levels below detection after three 3-week transfer periods in 0 nM and 20 nM tungsten. In sugar mix, AigG4 abundance levels varied wildly in 0 nM tungsten after the fifth transfer period suggesting tungsten contamination. Two newly designed FISH probes exhibited lower fluorescence signal intensity than the previously designed FISH probe suggesting issues with either target site accessibility or conjugation of the fluorescent moiety to oligonucleotide probes

An Application of Evolutionary Game Theory to Social Dilemmas: The Traveler's Dilemma and the Minimum Effort Coordination Game

The Traveler's Dilemma game and the Minimum Effort Coordination game are two social dilemmas that have attracted considerable attention due to the fact that the predictions of classical game theory are at odds with the results found when the games are studied experimentally. Moreover, a direct application of deterministic evolutionary game theory, as embodied in the replicator dynamics, to these games does not explain the observed behavior. In this work, we formulate natural variants of these two games as smoothed continuous-strategy games. We study the evolutionary dynamics of these continuous-strategy games, both analytically and through agent-based simulations, and show that the behavior predicted theoretically is in accord with that observed experimentally. Thus, these variants of the Traveler's Dilemma and the Minimum Effort Coordination games provide a simple resolution of the paradoxical behavior associated with the original games

Silicon and tungsten oxide nanostructures for water splitting

Inorganic semiconductors are promising materials for driving photoelectrochemical water-splitting reactions. However, there is not a single semiconductor material that can sustain the unassisted splitting of water into H_2 and O_2. Instead, we are developing a three part cell design where individual catalysts for water reduction and oxidation will be attached to the ends of a membrane. The job of splitting water is therefore divided into separate reduction and oxidation reactions, and each catalyst can be optimized independently for a single reaction. Silicon might be suitable to drive the water reduction. Inexpensive highly ordered Si wire arrays were grown on a single crystal wafer and transferred into a transparent, flexible polymer matrix. In this array, light would be absorbed along the longer axial dimension while the resulting electrons or holes would be collected along the much shorter radial dimension in a massively parallel array resembling carpet fibers on a microscale, hence the term "solar carpet". Tungsten oxide is a good candidate to drive the water oxidation. Self-organized porous tungsten oxide was successfully synthesized on the tungsten foil by anodization. This sponge-like structure absorbs light efficiently due to its high surface area; hence we called it "solar sponge"

Positive and Negative Regulatory Elements in the HIV-1 5'UTR Control Specific Recognition by Gag

Biological Sciences (The Ohio State University Denman Undergraduate Research Forum)The 5ʹ untranslated region (5ʹUTR) of the human immunodeficiency virus type 1 (HIV-1) genomic RNA (gRNA) contains a structured RNA element (termed Psi) that is specifically recognized by the HIV-1 Gag polyprotein, ensuring that two strands of gRNA are packaged into newly assembled virions. However, the mechanism by which Gag recognizes gRNA over other cellular RNAs and spliced viral RNAs is not well understood. A recent study suggested that a negative regulatory element upstream of Psi reduces high-affinity Gag binding, and a positive regulatory element downstream of Psi counteracts the upstream element and restores high-affinity binding. The aim of this study is to determine how these elements affect the specificity and mode of Gag binding. Using a fluorescence anisotropy-based salt-titration binding assay, the electrostatic and nonelectrostatic (i.e., specific) components of binding were measured. We have previously shown that Gag interacts with a 109-nucleotide (nt) Psi RNA construct that lacks the putative regulatory elements with high specificity and relatively few electrostatic interactions. Using a 356-nt RNA construct that includes the negative regulatory element in addition to Psi, we observed a loss in Gag binding specificity and an increase in electrostatic interactions. Interestingly, a 400-nt construct that contains the positive and negative elements flanking Psi restored highly specific binding and reduced the electrostatic interactions made with the RNA. Furthermore, a construct wherein the 40-nt positive regulatory element was appended to Psi, demonstrated the same specificity as Psi alone. Taken together, these data are consistent with a mechanism whereby the negative and positive regulatory elements flanking Psi modulate Gag binding mode and specificity.Undergraduate Education Summer Research FellowshipArts & Sciences Undergraduate Research ScholarshipSOLAR Research GrantNo embargoAcademic Major: Biochemistr

Propuesta metodológica para la gestión de proyectos de investigación y desarrollo en el área de las tecnologías de información y comunicación(TIC), con participación academica y empresarial

Tesis (Ingeniero en Sistemas)--Universidad Americana, Managua, 2005Es una propuesta metodológica para la gestión de proyectos de investigación y desarrollo en el área de Tecnologías de Información y Comunicación (TIC), con participación académica y empresarial, a fin de brindar una herramienta que guíe a las universidades y empresas en la gestión de proyectos de I+D en el área de TIC, tomando en consideración que todo lo descrito a través de esta propuesta metodológica servirá de insumo para la realización de nuevas investigaciones, orientadas a renovar el conocimiento a partir de las experiencias obtenidas mediante el desarrollo de proyectos de I+D en el área de las TIC en el que participen universidades y empresas

Aplicación de Amilasa para la reducción de Aceites y Grasas de los efluentes generados en el proceso de lavado de autos Comas - Lima, 2017

El objetivo principal de este trabajo ha sido orientado a plantear solución al vertimiento de aguas residuales sin tratamiento, dichas aguas residuales son provenientes de los servicios de lavado de vehículos, en el que se utilizan aproximadamente 225 m3 de agua al mes. Las características que presenta este efluente son concentraciones elevadas de hidrocarburos. En la presente investigación se busca el control del parámetro aceites y grasas mediante la aplicación de Amilasa, para el proceso inicial del tratamiento se realizó la selección de la muestra de manera intencional tomándose una muestra de 11 litros teniendo como una muestra de testigo durante todo el tiempo de tratamiento. Durante el tiempo de tratamiento se controlaron los parámetros de pH y temperatura durante la aplicación de la Amilasa en el efluente, así mismo se controló los aceites y grasas antes de la aplicación y después del tratamiento para verificar la tendencia en reducción del parámetro aceites y grasas en el efluente. El periodo de tratamiento duro 10 semanas, en el que se realizó la aplicación de Amilasa en las siguientes concentraciones 4 gr, 5 gr, 6 gr, 7 gr. La aplicación de estas concentraciones al agua residual fue evaluada con una muestra de control o testigo en todas las repeticiones realizadas. Los resultados de los análisis realizados en la degradación del parámetro de los aceites y grasas cuando se realizó la aplicación de 7 gr de Amilasa, obteniendo el mejor resultado de 563.15 mg/L de aceites y grasas reduciéndose hasta un 49% de reducción. Este resultado fue contrastado con la muestra testigo que se manejó en todos los muestreos realizados. Por lo tanto, los resultados obtenidos respondieron satisfactoriamente a la hipótesis planteada en la presente investigación La aplicación de Amilasa en condiciones normales permite la degradación del parámetro aceites y grasas de las aguas residuales del proceso de lavado de vehículo