CTP synthase and transporter function in Coxiella burnetii

Coxiella burnetii is a gram negative, obligate intracellular parasite that can only replicate in the acidified environment of a phagosome. Like other intracellular parasites, C. burnetii depends on the host cell for many of the substrates required for growth, such as amino acids. It had been observed that avirulent C. burnetii Nine Mile strain (Phase II) organisms in BHK-21 fibroblasts displayed improved growth when extracellular cytidine was introduced to infected cultures. This improved growth was not observed in wild type organisms in the same cell system. This observation, coupled with early enzyme activity studies, suggested that Phase II organisms had an inactive CTP synthase enzyme. To verify this hypothesis, nucleoside transport studies were performed in vitro in acidified media that determined that both wild type C. burnetii and the avirulent variant are permeable to nucleosides, but not nucleotides or nucleobases. Further, the CTP synthase gene from the wild type and avirulent organisms were sequenced and compared. The enzyme activity was examined by using both cell-free extacts and hexahistidine-tagged recombinant CTP synthase cloned from the wild type C. burnetii genome. It was found that the Phase I and Phase II CTP synthase genes were identical. Further, it was shown that the avirulent organism had a functional CTP synthase enzyme and that neither nucleoside transport nor CTP synthase activity were the explanations for the lower growth rate of Phase II organisms in BHK-21 fibroblasts. While the hypothesis was found to be invalid, enzyme inhibition experiments suggest the C. burnetii CTP synthase may be a potential target for drug development

The Hip in Hip Hop: Toward a Discipline of Hip Hop Studies

Editorial

Asymmetric Corporate Exposures to Foreign Exchange Rates

Research examining firms\u27 economic exposures to exchange rate movements has not differentiated periods of foreign currency appreciation and depreciation when estimating exposure coefficients. Recent theoretical developments regarding real options and pricing-to-market suggest corporate exposures may be asymmetric (i.e., the financial performance impact of a foreign currency appreciation may not be offset by the currency\u27s depreciation). Through an empirical examination of manufacturing firms\u27 economic exposures to exchange rate movements, this paper furnishes evidence on exposure asymmetries

Approximate Inference for Constructing Astronomical Catalogs from Images

We present a new, fully generative model for constructing astronomical catalogs from optical telescope image sets. Each pixel intensity is treated as a random variable with parameters that depend on the latent properties of stars and galaxies. These latent properties are themselves modeled as random. We compare two procedures for posterior inference. One procedure is based on Markov chain Monte Carlo (MCMC) while the other is based on variational inference (VI). The MCMC procedure excels at quantifying uncertainty, while the VI procedure is 1000 times faster. On a supercomputer, the VI procedure efficiently uses 665,000 CPU cores to construct an astronomical catalog from 50 terabytes of images in 14.6 minutes, demonstrating the scaling characteristics necessary to construct catalogs for upcoming astronomical surveys.Comment: accepted to the Annals of Applied Statistic

Marine Archeological Survey of the Proposed Bolivar Ferry Dredge Spoil Pile Expansion Area, Galveston County, Texas

Archeologists from AmaTerra Environmental, Inc. (AmaTerra) and Southeastern Archaeological Research, Inc. (SEARCH; collectively the Team) conducted intensive underwater archeological remote sensing survey on behalf of the Texas Department of Transportation (TxDOT) on a proposed dredge spoil expansion area south of the Bolivar Peninsula at the mouth of Galveston Bay, Galveston County, Texas. The survey was required for compliance with the National Historic Preservation Act of 1966, as amended, due to dredge permits to be issued by the US Fish and Wildlife Service, and the Antiquities Code of Texas, due to its location on lands owned by a political subdivision of the State of Texas (the Texas General Land Office). Completed under Antiquities Permit 6272, the survey area includes the 51-acre dredge spoil expansion footprint and the original 16-acre dredge spoil pile (67 acres total). The archeologists utilized towed marine magnetometer and side-scan sonar survey along 12 parallel, 20-meter-interval transects to assess the full archeological Area of Potential Effects. The survey area was found to be littered with isolated modern metallic debris. Side-scan sonar imagery revealed a submerged surface that was generally flat with no indications of shipwrecks and a large oyster reef along the southwestern quarter. One large metallic feature located within the survey area (Anomaly M1) was identified as a fallen modern navigational sighting marker tower. None of the archeological survey data, sensor readings, or imagery from the proposed expansion area is consistent with expected signatures of historic-age shipwrecks. Archeologists did re-identify the previously-documented magnetic anomaly M44 that was recommended for avoidance or testing within the original dredge pile area. If the avoidance zone continues to be observed, it will not be impacted by the current undertaking. As such, the project is recommended to proceed with no Historic Properties, State Archeological Landmarks, or archeological sites impacted in accordance with guidelines outlined in 36 CFR 800 and 13 TAC 26. No sites were identified and no artifacts were collected during the course of the survey. Accordingly, all project-generated notes, forms, and other materials will be permanently curated at AmaTerra’s office in Austin, Texas and SEARCH’s office in Pensacola, Florida

Bioavailability of Cadmium in Inexpensive Jewelry

Objectives: We evaluated the bioavailability of Cd in 86 components of 57 jewelry items found to contain high levels of Cd (> 10,000 ppm) by X-ray fluorescence (XRF), using extractions that simulate mouthing or swallowing of jewelry items

‘No One Should Destroy the Forest\u27: Using photo-based vignette interviews to understand Kenyan teachers\u27 views of the environment

In the midst of the current environmental crisis, scientists, academics, authors, and politicians worldwide are urging citizens to create sustainable communities. However, there is little capability to build a sustainable society without an informed, active, and engaged populous. This requires more than just environmentally knowledgeable citizens. It requires a society that understands the principles of the environment and can also exemplify them in daily life. In order to create a more environmentally literate world, there has been a push for environmental education integrated into schools. This qualitative study sought to examine Kenyan teachers’ perspectives on the human–nature interaction by conducting vignette focus-group interviews. It is a subject not widely explored but vital for conservation not only in this area, but also other areas that seek to have an ecological informed populous. The vignettes were created using photographs and explanations of the photographs that the participants collected and emailed to the authors. For the focus-group vignette interviews, there were a total of 55 participants (30 females and 25 males). After InVivo analysis, we had 6 codes (resentment, pride, perils, blame, pragmatism, and self-interested) within 3 major themes. This study has implications for informing science education to combat these traditions of subjecting students to a science curriculum that demotes Kenyan cultural heritage and lifestyle. By incorporating local knowledge such as the ideas discussed in this paper into Kenyan science education, Kenyans can reach one of most challenging objectives of education, which is to produce children who are fundamentally aware of their environment

Multitissue molecular, genomic, and developmental effects of the deepwater horizon oil spill on resident Gulf killifish (Fundulus grandis)

The Deepwater Horizon oil rig disaster resulted in crude oil contamination along the Gulf coast in sensitive estuaries. Toxicity from exposure to crude oil can affect populations of fish that live or breed in oiled habitats as seen following the Exxon Valdez oil spill. In an ongoing study of the effects of Deepwater Horizon crude oil on fish, Gulf killifish (Fundulus grandis) were collected from an oiled site (Grande Terre, LA) and two reference locations (coastal MS and AL) and monitored for measures of exposure to crude oil. Killifish collected from Grande Terre had divergent gene expression in the liver and gill tissue coincident with the arrival of contaminating oil and up-regulation of cytochrome P4501A (CYP1A) protein in gill, liver, intestine, and head kidney for over one year following peak landfall of oil (August 2011) compared to fish collected from reference sites. Furthermore, laboratory exposures of Gulf killifish embryos to field-collected sediments from Grande Terre and Barataria Bay, LA, also resulted in increased CYP1A and developmental abnormalities when exposed to sediments collected from oiled sites compared to exposure to sediments collected from a reference site. These data are predictive of population-level impacts in fish exposed to sediments from oiled locations along the Gulf of Mexico coast. © 2013 American Chemical Society

Investigation of the Prebiotic Synthesis of Amino Acids and RNA Bases from CO2 Using FeS/H2S As a Reducing Agent

An autotrophic theory of the origin of metabolism and life has been proposed in which carbon dioxide is reduced by ferrous sulfide and hydrogen sulfide by means of a reversed citric acid cycle, leading to the production of amino acids. Similar processes have been proposed for purine synthesis. Ferrous sulfide is a strong reducing agent in the presence of hydrogen sulfide and can produce hydrogen as well as reduce alkenes, alkynes, and thiols to saturated hydrocarbons and reduce ketones to thiols. However, the reduction of carbon dioxide has not been demonstrated. We show here that no amino acids, purities, or pyrimidines are produced from carbon dioxide with the ferrous sulfide and hydrogen sulfide system. Furthermore, this system does not produce amino acids from carboxylic acids by reductive amination and carboxylation. Thus, the proposed autotrophic theory, using carbon dioxide, ferrous sulfide, and hydrogen sulfide, lacks the robustness needed to be a geological process and is, therefore, unlikely to have played a role In the origin of metabolism or the origin of life

Investigation of the Prebiotic Synthesis of Amino Acids and RNA Bases from CO2 using FeS/H2S as a Reducing Agent

An autotrophic theory of the origin of metabolism and life has been proposed in which carbon dioxide is reduced by ferrous sulfide and hydrogen sulfide by means of a reversed citric acid cycle, leading to the production of amino acids. Similar processes have been proposed for purine synthesis. Ferrous sulfide is a strong reducing agent in the presence of hydrogen sulfide and can produce hydrogen as well as reduce alkenes, alkynes, and thiols to saturated hydrocarbons and reduce ketones to thiols. However, the reduction of carbon dioxide has not been demonstrated. We show here that no amino acids, purines, or pyrimidines are produced from carbon dioxide with the ferrous sulfide and hydrogen sulfide system. Furthermore, this system does not produce amino acids from carboxylic acids by reductive amination and carboxylation. Thus, the proposed autotrophic theory, using carbon dioxide, ferrous sulfide, and hydrogen sulfide, lacks the robustness needed to be a geological process and is, therefore, unlikely to have played a role in the origin of metabolism or the origin of life