666 research outputs found

    Effect of Media and Estrogen on Morphological Change in Candida albicans

    Get PDF
    Introduction: Candida albicans (C. albicans), an opportunistic pathogen, lives symbiotically within the intestine of its human host. Temperature and chemical factors have been shown to induce a morphological change in C. albicans from yeast to filamentous form turning C. albicans pathogenic. In this study, we investigated the intestinal cues that might be responsible for the change. We found that different solid media impact the morphological phenotype so we focused on characterizing these before further testing. We tested Estradiol (E2) because of its known linkage to sepsis and higher levels during infections. Experiments were conducted to compare solid agar plates of YEPD, Minimal Media (MM), and Spider Media (SP) for C. albicans growth to choose the best one for further testing with E2 and other factors that could be prone to causing morphological changes. Methods: C. albicans was inoculated through streak method on different solid media (YEPD, MM, SP) and incubated at 30℃. The effect of 0.1nM E2 on C. albicans morphology was also tested. Morphological changes were assayed through bright-field microscopy. Results: Using the three different medias, we found three distinctive phenotypes: A, B, and C. Out of 6 experiments of 14 MM plates, the expressed phenotype was 86% A and 14% inconclusive of the time. 8 experiments of 17 SP plates showed 100% of phenotype B. 6 experiments of 14 YEPD plates presented phenotype C 92% of the time and 8% inconclusive. For E2 trials, 2 experiments, 6 MM plates showed 50% phenotype A and 50% inconclusive. 4 experiments, 10 SP plates had phenotype B 100%. YEPD 2 experiments, 2 plates had phenotype C at 100%. Conclusion: We have established experimental conditions of media controls for further testing whether E2 and other cues, such as inflammatory cytokines, have inhibitory or positive effects on the growth of C. albicans

    High-fructose corn-syrup-sweetened beverage intake increases 5-hour breast milk fructose concentrations in lactating women

    Get PDF
    This study determined the effects of consuming a high-fructose corn syrup (HFCS)-sweetened beverage on breast milk fructose, glucose, and lactose concentrations in lactating women. At six weeks postpartum, lactating mothers (n = 41) were randomized to a crossover study to consume a commercially available HFCS-sweetened beverage or artificially sweetened control beverage. At each session, mothers pumped a complete breast milk expression every hour for six consecutive hours. The baseline fasting concentrations of breast milk fructose, glucose, and lactose were 5.0 ± 1.3 µg/mL, 0.6 ± 0.3 mg/mL, and 6.8 ± 1.6 g/dL, respectively. The changes over time in breast milk sugars were significant only for fructose (treatment × time, p < 0.01). Post hoc comparisons showed the HFCS-sweetened beverage vs. control beverage increased breast milk fructose at 120 min (8.8 ± 2.1 vs. 5.3 ± 1.9 µg/mL), 180 min (9.4 ± 1.9 vs. 5.2 ± 2.2 µg/mL), 240 min (7.8 ± 1.7 vs. 5.1 ± 1.9 µg/mL), and 300 min (6.9 ± 1.4 vs. 4.9 ± 1.9 µg/mL) (all p < 0.05). The mean incremental area under the curve for breast milk fructose was also different between treatments (14.7 ± 1.2 vs. −2.60 ± 1.2 µg/mL × 360 min, p < 0.01). There was no treatment × time interaction for breast milk glucose or lactose. Our data suggest that the consumption of an HFCS-sweetened beverage increased breast milk fructose concentrations, which remained elevated up to five hours post-consumption

    The Interaction Among Multiple Governance Mechanisms at Young, Newly Public Firms

    Get PDF
    We focus on the relations among inside ownership, board composition, unaffiliated block ownership, and compensation structure for a sample of firms following their IPOs. Specifically, we follow firms for up to eleven years after their IPOs and examine the full sample and subsamples of firms that survive, are acquired, or that file for bankruptcy during the sample period. We find that as CEO ownership declines, board independence, board seats held by venture capitalists, and unaffiliated block ownership increase. Our findings suggest that as inside ownership decreases alternative governance mechanisms evolve to help mitigate the resulting increase in agency costs. Interestingly, the associations between CEO ownership, the fraction of venture capital board membership, and unaffiliated block ownership exist only for firms that survive over the eleven-year sample period

    Effect of Media and Estrogen on Morphological Change in Candida albicans

    Get PDF
    Introduction: Candida albicans (C. albicans), an opportunistic pathogen, lives symbiotically within the intestine of its human host. Temperature and chemical factors have been shown to induce a morphological change in C. albicans from yeast to filamentous form turning C. albicans pathogenic. In this study, we investigated the intestinal cues that might be responsible for the change. We found that different solid media impact the morphological phenotype so we focused on characterizing these before further testing. We tested Estradiol (E2) because of its known linkage to sepsis and higher levels during infections. Experiments were conducted to compare solid agar plates of YEPD, Minimal Media (MM), and Spider Media (SP) for C. albicans growth to choose the best one for further testing with E2 and other factors that could be prone to causing morphological changes. Methods: C. albicans was inoculated through streak method on different solid media (YEPD, MM, SP) and incubated at 30℃. The effect of 0.1nM E2 on C. albicans morphology was also tested. Morphological changes were assayed through bright-field microscopy. Results: Using the three different medias, we found three distinctive phenotypes: A, B, and C. Out of 6 experiments of 14 MM plates, the expressed phenotype was 86% A and 14% inconclusive of the time. 8 experiments of 17 SP plates showed 100% of phenotype B. 6 experiments of 14 YEPD plates presented phenotype C 92% of the time and 8% inconclusive. For E2 trials, 2 experiments, 6 MM plates showed 50% phenotype A and 50% inconclusive. 4 experiments, 10 SP plates had phenotype B 100%. YEPD 2 experiments, 2 plates had phenotype C at 100%. Conclusion: We have established experimental conditions of media controls for further testing whether E2 and other cues, such as inflammatory cytokines, have inhibitory or positive effects on the growth of C. albicans

    Study Title-Based Framing Effects on Reports of Sexual Violence Factors in College Students

    Get PDF
    Objective: There are many methodological issues in studying sexual violence, including potential framing effects. Framing effects refer to how researchers communicate the purpose of a study to participants, such as, how the study is advertised or explained. The aim of the current study was to investigate if framing effects were associated with differences in participants’ self-reported experiences of sexual violence and related correlates. Methods: College students (N = 782) were recruited to participate in one of four identical studies that differed in the title: “Questionnaires about Alcohol,” “Questionnaires about Crime,” “Questionnaires about Health,” or “Questionnaires about Sexual Assault.” Participants chose one of the four studies and completed measures of sexual violence as well as attitudinal and behavioral measures in randomized order. Results: We found significantly more reports of childhood sexual abuse (33.6% vs. 18.5%), rape (33.9% vs. 21.1%), higher frequency of victimization (M = 11.35 vs. 5.44), and greater acknowledged rape for bisexual people (46.2% vs. 0.0%) in the Sexual Assault condition compared to other conditions. There were no differences in sexual violence perpetration or attitudinal or behavioral measures. Conclusion: These results revealed that framing effects, based on the study title, affect outcomes in sexual victimization research. Rape was reported 1.6x more in the “Sexual Assault” condition than in the “Health” condition. It is unclear whether these framing effects reflect self-selection bias or framing related increased reports in the Sexual Assault condition, suppression of reports in other conditions, or a combination thereof

    Role of Stone-Wales Defects on the Interfacial Interactions Among Graphene, Carbon Nanotubes, and Nylon 6: A First-Principles Study

    Get PDF
    We investigate computationally the role of Stone-Wales (SW) defects on the interfacial interactions among graphene, carbon nanotubes (CNTs), and Nylon 6 using density functional theory (DFT) and the empirical force-field. Our first-principles DFT calculations were performed using the Quantum ESPRESSO electronic structure code with the highly accurate van der Waals functional (vdW-DF2). Both pristine and SW-defected carbon nanomaterials were investigated. The computed results show that the presence of SW defects on CNTs weakens the CNT-graphene interactions. Our result that CNT-graphene interaction is much stronger than CNT-CNT interaction indicates that graphene would be able to promote the dispersion of CNTs in the polymer matrix. Our results demonstrate that carbon nanomaterials form stable complexes with Nylon 6 and that the van der Waals interactions, as revealed by the electronic charge density difference maps, play a key stabilizing role on the interfacial interactions among graphene, CNTs, and Nylon 6. Using the density of states calculations, we observed that the bandgaps of graphene and CNTs were not significantly modified due to their interactions with Nylon 6. The Young’s moduli of complexes were found to be the averages of the moduli of their individual constituents. Published by AIP Publishing. https://doi.org/10.1063/1.503208

    Genome Sequence of Mycobacterium Phage Waterfoul

    Get PDF
    Waterfoul is a new isolated temperate siphovirus of Mycobacterium smegmatis mc2155. It was identified as a member of the K5 cluster of Mycobacterium phages and has a 61,248-bp genome with 95 predicted genes

    Turnover of variant surface glycoprotein in Trypanosoma brucei is a bimodal process

    Get PDF
    This work was supported by United States Public Health Service grant R01 AI035739 and funds from the Jacobs School of Medicine and Biomedical Sciences to J.D.B. and from United States Public Health Service grant 1S10OD021719-01A1 to the University of Georgia, which purchased the ImageStreamX Mk II. This work was also supported by the Wellcome Trust (grant 094476/Z/10/Z) for funding the purchase of the TripleTOF 5600 mass spectrometer at the BSRC Mass Spectrometry and Proteomics Facility.African trypanosomes utilize glycosylphosphatidylinositol (GPI)-anchored variant surface glycoprotein (VSG) to evade the host immune system. VSG turnover is thought to be mediated via cleavage of the GPI anchor by endogenous GPI-specific phospholipase C (GPI-PLC). However, GPI-PLC is topologically sequestered from VSG substrates in intact cells. Recently, A. J. Szempruch, S. E. Sykes, R. Kieft, L. Dennison, et al. (Cell 164:246-257, 2016, https://doi.org/10.1016/j.cell.2015.11.051) demonstrated the release of nanotubes that septate to form free VSG+ extracellular vesicles (EVs). Here, we evaluated the relative contributions of GPI hydrolysis and EV formation to VSG turnover in wild-type (WT) and GPI-PLC null cells. The turnover rate of VSG was consistent with prior measurements (half-life [t1/2] of ∼26 h) but dropped significantly in the absence of GPI-PLC (t1/2 of ∼36 h). Ectopic complementation restored normal turnover rates, confirming the role of GPI-PLC in turnover. However, physical characterization of shed VSG in WT cells indicated that at least 50% is released directly from cell membranes with intact GPI anchors. Shedding of EVs plays an insignificant role in total VSG turnover in both WT and null cells. In additional studies, GPI-PLC was found to have no role in biosynthetic and endocytic trafficking to the lysosome but did influence the rate of receptor-mediated endocytosis. These results indicate that VSG turnover is a bimodal process involving both direct shedding and GPI hydrolysis. IMPORTANCE African trypanosomes, the protozoan agent of human African trypanosomaisis, avoid the host immune system by switching expression of the variant surface glycoprotein (VSG). VSG is a long-lived protein that has long been thought to be turned over by hydrolysis of its glycolipid membrane anchor. Recent work demonstrating the shedding of VSG-containing extracellular vesicles has led us to reinvestigate the mode of VSG turnover. We found that VSG is shed in part by glycolipid hydrolysis but also in approximately equal part by direct shedding of protein with intact lipid anchors. Shedding of exocytic vesicles made a very minor contribution to overall VSG turnover. These results indicate that VSG turnover is a bimodal process and significantly alter our understanding of the "life cycle" of this critical virulence factor.Publisher PDFPeer reviewe
    corecore