862 research outputs found

    An Annotated and Illustrated Key to Multistage Larvae of Ohio Salamanders

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    Author Institution: Department of Zoology, University of Illinois, Urban

    The Salamanders of Southeastern Ohio

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    Author Institution: Department of Zoology, Ohio University, Athens, Ohi

    Antibiotic resistance in Bacillus subtilis as affected by transcriptional derepression and the stringent response

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    Bacterial cells under conditions of starvation or prolonged non-lethal selective pressures accumulate mutations in highly transcribed genes. This process is part of cellular programs to increase genetic diversity in conditions of stress, also known as stationary phase or stress-induced mutagenesis. This experiment investigated mutation frequencies for antibiotic resistance as affected by the stringent response. The stringent response is a global cellular process that initiates at the cessation of growth and mediates changes in gene expression that repress synthesis of ribosome components. We used Bacillus subtilis strains that differ in RelA proficiency. The relA gene controls the synthesis of (p)ppGpp, the signaling molecule which mediates the stringent response. Since genes involved in protein synthesis are repressed during the stringent response, we hypothesize that relaxed mutants express a higher accumulation of mutations that confer resistance to tetracycline than cells that become stringent. Resistance to tetracycline may be acquired by altering components of the small subunit of bacterial ribosomes. Utilizing an overlay procedure and increasing times of incubation under nutritional stress, stationary cells were prompted for resistance to tetracycline. Our results showed that relA- cells expressed a higher accumulation of Tcr mutations than the one observed in wild type cells. These results provide evidence that transcriptional derepression in cells under non-lethal stress mediates mutagenic events. Implications in antibiotic resistance are further discussed

    Validity of Borg Ratings of Perceived Exertion During Active Video Game Play

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    International Journal of Exercise Science 6(2) : 164-170, 2013. During physically interactive video game play (e.g., Nintendo Wii), users are exposed to potential distracters (e.g., video, music), which may decrease their ratings of perceived exertion (RPE) throughout game play. The purpose of this investigation was to determine the association between RPE scores and heart rate while playing the Nintendo Wii. Healthy adults (N = 13, 53.5 ± 5.4 years old) participated in two exercise sessions using the Nintendo Wii Fit Plus. During each session participants played a five-minute warm-up game (Basic Run), two separate Wii Fit Plus games (Yoga, Strength Training, Aerobics or Balance Training) for fifteen minutes each, and then a five-minute cool down game (Basic Run). Borg RPE and heart rate were assessed during the final 30 seconds of the warm up and cool down, as well during the final 30 seconds of play for each Wii Fit Plus game. Correlation analysis combining data from both exercise sessions indicated a moderate positive relationship between heart rate and RPE (r = 0.32). Mixed-effects model regression analyses demonstrated that RPE scores were significantly associated with heart rate (p \u3c 0.001). The average percentage of age-predicted heart rate maximum achieved (58 ± 6%) was significantly greater (p = 0.001) than the percentage of maximum RPE indicated (43 ± 11%). Borg RPE scores were positively associated with heart rate in adults during exercise sessions using the Wii Fit Plus. However, this relationship was lower than observed in past research assessing RPE validity during different modes of exercise (e.g. walking, running) without distracters
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