688 research outputs found

    Methanol production by a broad phylogenetic array of marine phytoplankton

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    © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS 11 (2016): e0150820, doi:10.1371/journal.pone.0150820.Methanol is a major volatile organic compound on Earth and serves as an important carbon and energy substrate for abundant methylotrophic microbes. Previous geochemical surveys coupled with predictive models suggest that the marine contributions are exceedingly large, rivaling terrestrial sources. Although well studied in terrestrial ecosystems, methanol sources are poorly understood in the marine environment and warrant further investigation. To this end, we adapted a Purge and Trap Gas Chromatography/Mass Spectrometry (P&T-GC/MS) method which allowed reliable measurements of methanol in seawater and marine phytoplankton cultures with a method detection limit of 120 nanomolar. All phytoplankton tested (cyanobacteria: Synechococcus spp. 8102 and 8103, Trichodesmium erythraeum, and Prochlorococcus marinus), and Eukarya (heterokont diatom: Phaeodactylum tricornutum, coccolithophore: Emiliania huxleyi, cryptophyte: Rhodomonas salina, and non-diatom heterokont: Nannochloropsis oculata) produced methanol, ranging from 0.8–13.7 micromolar in culture and methanol per total cellular carbon were measured in the ranges of 0.09–0.3%. Phytoplankton culture time-course measurements displayed a punctuated production pattern with maxima near early stationary phase. Stabile isotope labeled bicarbonate incorporation experiments confirmed that methanol was produced from phytoplankton biomass. Overall, our findings suggest that phytoplankton are a major source of methanol in the upper water column of the world’s oceans.This project was solely supported by a grant to TJM from the National Science Foundation (Award# CHE-OCE 1131415)

    Comparison of Sport Tourist and Local Participants’ Sponsorship and Charity Recall and Intentions

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    Running events have proliferated in the last decade and rely on sponsorships for income. However, more needs to be discovered about how effective these sponsorships are in encouraging purchase behavior and connecting to charity organizations. This study aims to develop a stronger understanding of running event participants and their attitudes toward sponsorships and charity organizations. Local participants were compared to sport tourists to determine if differences existed in the recall or potential use of the sponsor’s product. Also, this study used self-determination theory to determine the impact of motivation on sponsorship recall and purchase intentions. A total of 201 respondents completed a survey at a major running event. Results indicated sport participants were likely to recall sponsors with a high level of perceived fit. Additionally, participants intended to purchase products from the running shoe company. Participants also had a high level of recall for the main charity and intended to donate money. Local participants were more likely to donate time to charity and purchase sponsor products than sport event tourists. Finally, autonomously motivated participants were more likely to recall sponsors. Keywords: Sport, Sponsorship, Charit

    Vitamin C inhibits endothelial cell apoptosis in congestive heart failure

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    Background - Proinflammatory cytokines like tumor necrosis factor- and oxidative stress induce apoptotic cell death in endothelial cells (ECs). Systemic inflammation and increased oxidative stress in congestive heart failure (CHF) coincide with enhanced EC apoptosis and the development of endothelial dysfunction. Therefore, we investigated the effects of antioxidative vitamin C therapy on EC apoptosis in CHF patients. Methods and Results - Vitamin C dose dependently suppressed the induction of EC apoptosis by tumor necrosis factor- and angiotensin II in vitro as assessed by DNA fragmentation, DAPI nuclear staining, and MTT viability assay. The antiapoptotic effect of vitamin C was associated with reduced cytochrome C release from mitochondria and the inhibition of caspase-9 activity. To assess EC protection by vitamin C in CHF patients, we prospectively randomized CHF patients in a double-blind trial to vitamin C treatment versus placebo. Vitamin C administration to CHF patients markedly reduced plasma levels of circulating apoptotic microparticles to 32±8% of baseline levels, whereas placebo had no effect (87±14%, P<0.005). In addition, vitamin C administration suppressed the proapoptotic activity on EC of the serum of CHF patients (P<0.001). Conclusions - Administration of vitamin C to CHF patients suppresses EC apoptosis in vivo, which might contribute to the established functional benefit of vitamin C supplementation on endothelial function

    Are You Welcomed? A Racial and Ethnic Comparison of Perceived Welcomeness in Sport Participation

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    International Journal of Exercise Science 10(6): 833-844, 2017. Sport has become racialized such that minority youth accrue limited health and academic benefits from participation, compared to their White counterparts. Understanding the welcomeness that minorities feel in sport, leisure and physical activities plays an important role in breaking down barriers to participation. Thus, the overall aim of this study is to further examine the determinants of sport participation, particularly as it relates to race, socialization and perceived welcomeness. College students (N = 451) scored their perceived level of welcomeness for Whites, African Americans and Hispanic/Latinos in 14 sports. Results reveal significant differences in the perceived welcomeness felt by Whites, African Americans and Hispanic/Latinos in most of the sports analyzed. The discussion focuses on the socialization agents that facilitate such racialized perceptions and hinder access and opportunities for racial and ethnic minority youth to experience the health, academic and social benefits of sport participation

    Fire and grazing in a mesic tallgrass prairie: impacts on plant species and functional traits

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    Fire is a globally distributed disturbance that impacts terrestrial ecosystems and has been proposed to be a global “herbivore.” Fire, like herbivory, is a top-down driver that converts organic materials into inorganic products, alters community structure, and acts as an evolutionary agent. Though grazing and fire may have some comparable effects in grasslands, they do not have similar impacts on species composition and community structure. However, the concept of fire as a global herbivore implies that fire and herbivory may have similar effects on plant functional traits. Using 22 years of data from a mesic, native tallgrass prairie with a long evolutionary history of fire and grazing, we tested if trait composition between grazed and burned grassland communities would converge, and if the degree of convergence depended on fire frequency. Additionally, we tested if eliminating fire from frequently burned grasslands would result in a state similar to unburned grasslands, and if adding fire into a previously unburned grassland would cause composition to become more similar to that of frequently burned grasslands. We found that grazing and burning once every four years showed the most convergence in traits, suggesting that these communities operate under similar deterministic assembly rules and that fire and herbivory are similar disturbances to grasslands at the trait-group level of organization. Three years after reversal of the fire treatment we found that fire reversal had different effects depending on treatment. The formerly unburned community that was then burned annually became more similar to the annually burned community in trait composition suggesting that function may be rapidly restored if fire is reintroduced. Conversely, after fire was removed from the annually burned community trait composition developed along a unique trajectory indicating hysteresis, or a time lag for structure and function to return following a change in this disturbance regime. We conclude that functional traits and species-based metrics should be considered when determining and evaluating goals for fire management in mesic grassland ecosystems
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