315 research outputs found

    Formins Determine the Functional Properties of Actin Filaments in Yeast

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    The actin cytoskeleton executes a broad range of essential functions within a living cell. The dynamic nature of the actin polymer is modulated to facilitate specific cellular processes at discrete locations by actin-binding proteins (ABPs), including the formins and tropomyosins (Tms). Formins nucleate actin polymers, while Tms are conserved dimeric proteins that form polymers along the length of actin filaments. Cells possess different Tm isoforms, each capable of differentially regulating the dynamic and func- tional properties of the actin polymer. However, the mecha- nism by which a particular Tm localizes to a specific actin polymer is unknown. Here we show that specific formin family members dictate which Tm isoform will associate with a particular actin filament to modulate its dynamic and functional properties at specific cellular locations. Exchanging the localization of the fission yeast formins For3 and Cdc12 results in an exchange in localizations of Tm forms on actin polymers. This nucleator-driven switch in filament composition is reflected in a switch in actin dynamics, together with a corresponding change in the filament’s ability to regulate ABPs and myosin motor activity. These data establish a role for formins in dictating which specific Tm variant will associate with a growing actin filament and therefore specify the functional capacity of the actin filaments that they create

    The Transcriptional Regulator Np20 Is the Zinc Uptake Regulator in

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    Zinc is essential for all bacteria, but excess amounts of the metal can have toxic effects. To address this, bacteria have developed tightly regulated zinc uptake systems, such as the ZnuABC zinc transporter which is regulated by the Fur-like zinc uptake regulator (Zur). In Pseudomonas aeruginosa, a Zur protein has yet to be identified experimentally, however, sequence alignment revealed that the zinc-responsive transcriptional regulator Np20, encoded by np20 (PA5499), shares high sequence identity with Zur found in other bacteria. In this study, we set out to determine whether Np20 was functioning as Zur in P. aeruginosa. Using RT-PCR, we determined that np20 (hereafter known as zur) formed a polycistronic operon with znuC and znuB. Mutant strains, lacking the putative znuA, znuB, or znuC genes were found to grow poorly in zinc deplete conditions as compared to wild-type strain PAO1. Intracellular zinc concentrations in strain PAO-Zur (Δzur) were found to be higher than those for strain PAO1, further implicating the zur as the zinc uptake regulator. Reporter gene fusions and real time RT-PCR revealed that transcription of znuA was repressed in a zinc-dependent manner in strain PAO1, however zinc-dependent transcriptional repression was alleviated in strain PAO-Zur, suggesting that the P. aeruginosa Zur homolog (ZurPA) directly regulates expression of znuA. Electrophoretic mobility shift assays also revealed that recombinant ZurPA specifically binds to the promoter region of znuA and does not bind in the presence of the zinc chelator N,N′,N-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN). Taken together, these data support the notion that Np20 is the P. aeruginosa Zur, which regulates the transcription of the genes encoding the high affinity ZnuABC zinc transport system

    Letter from Matthew C. Perry, in Norfolk, Virginia aboard the U.S. Steam Frigate Mississippi, to William J.W. Clancy, commanding U.S. Steam Frigate Powhattan, directing him on the route by which he shall sail to Macau (China). November 23, 1852.

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    Intructions from Mathew C. Perry to William J.W. Clancy regarding his voyage on the Powhattan to China. Perry directs Clancy to stop in Madeira to refuel and then again at the Cape of Good Hope, and again at Mauritius or Isle of France. Perry also discusses other details of the voyage. November 23, 1852. Norfolk, Virginia, abourd the U.S Mississippi.https://digitalcommons.wofford.edu/littlejohnmss/1208/thumbnail.jp

    Energizers Classroom-based Physical Activities 3-5 : The way teachers integrate physical activity with academic concepts

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    Energizers are classroom-based physical activities that were designed to help teachers integrate physical activity with academic concepts. The energizers were developed by a team from the Activity Promotion Laboratory at East Carolina University. Teachers can download these activities free of charge and are encouraged to incorporate these activities into their classroom. Our research, published in the journal Medicine and Science in Sports and Exercise (2006, volume 38, number 12), demonstrated that: (a) Energizers are easy to implement; (b) both teachers and students enjoy the Energizers activities; (c) use of Energizers activities improves on-task behavior of students; and (d) use of Energizers increases the amount of physical activity accumulated over the course of the school day.Activity Promotion Laboratory: Projects Fulfilling a Nee

    Music Middle-School Energizers Classroom-based Physical Activities The way teachers integrate physical activity with academic concepts

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    Middle School Energizers are classroom-based physical activities that integrate physical activity with academic concepts. The Middle School Energizers were developed by a team from the Activity Promotion Laboratory at East Carolina University. We hope these 10-minute activities make it easier for teachers to implement physical activity into the classroom to improve classroom instruction and increase physical activity levels over the school day. Teachers can download these activities free of charge and are encouraged to incorporate these activities into their classroomActivity Promotion Laboratory: Projects Fulfilling a Nee

    Social Studies Middle-School Energizers Classroom-based Physical Activities The way teachers integrate physical activity with academic concepts

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    Activity Promotion Laboratory: Projects Fulfilling a NeedMiddle School Energizers Middle School Energizers are classroom-based physical activities that integrate physical activity with academic concepts. The Middle School Energizers were developed by a team from the Activity Promotion Laboratory at East Carolina University. We hope these 10-minute activities make it easier for teachers to implement physical activity into the classroom to improve classroom instruction and increase physical activity levels over the school day. Teachers can download these activities free of charge and are encouraged to incorporate these activities into their classroom.Activity Promotion Laboratory: Projects Fulfilling a Nee

    Healthful Living Middle-School Energizers Classroom-based Physical Activities The way teachers integrate physical activity with academic concepts

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    Middle School Energizers Middle School Energizers are classroom-based physical activities that integrate physical activity with academic concepts. The Middle School Energizers were developed by a team from the Activity Promotion Laboratory at East Carolina University. We hope these 10-minute activities make it easier for teachers to implement physical activity into the classroom to improve classroom instruction and increase physical activity levels over the school day. Teachers can download these activities free of charge and are encouraged to incorporate these activities into their classroom.Activity Promotion Laboratory: Projects Fulfilling a Nee

    The role of PPARγ in carbon nanotube-elicited granulomatous lung inflammation

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    BACKGROUND: Although granulomatous inflammation is a central feature of many disease processes, cellular mechanisms of granuloma formation and persistence are poorly understood. Carbon nanoparticles, which can be products of manufacture or the environment, have been associated with granulomatous disease. This paper utilizes a previously described carbon nanoparticle granuloma model to address the issue of whether peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear transcription factor and negative regulator of inflammatory cytokines might play a role in granulomatous lung disease. PPARγ is constitutively expressed in alveolar macrophages from healthy individuals but is depressed in alveolar macrophages of patients with sarcoidosis, a prototypical granulomatous disease. Our previous study of macrophage-specific PPARγ KO mice had revealed an intrinsically inflammatory pulmonary environment with an elevated pro-inflammatory cytokines profile as compared to wild-type mice. Based on such observations we hypothesized that PPARγ expression would be repressed in alveolar macrophages from animals bearing granulomas induced by MWCNT instillation. METHODS: Wild-type C57Bl/6 and macrophage-specific PPARγ KO mice received oropharyngeal instillations of multiwall carbon nanotubes (MWCNT) (100 μg). Bronchoalveolar lavage (BAL) cells, BAL fluids, and lung tissues were obtained 60 days post-instillation for analysis of granuloma histology and pro-inflammatory cytokines (osteopontin, CCL2, and interferon gamma [IFN-γ] mRNA and protein expression. RESULTS: In wild-type mice, alveolar macrophage PPARγ expression and activity were significantly reduced in granuloma-bearing animals 60 days after MWCNT instillation. In macrophage-specific PPARγ KO mice, granuloma formation was more extensive than in wild-type at 60 days after MWCNT instillation. PPARγ KO mice also demonstrated elevated pro-inflammatory cytokine expression in lung tissue, laser-microdissected lung granulomas, and BAL cells/fluids, at 60 days post MWCNT exposure. CONCLUSIONS: Overall, data indicate that PPARγ deficiency promotes inflammation and granuloma formation, suggesting that PPARγ functions as a negative regulator of chronic granulomatous inflammation

    Variation in pigmentation gene expression is associated with distinct aposematic color morphs in the poison frog Dendrobates auratus

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    Background: Color and pattern phenotypes have clear implications for survival and reproduction in many species. However, the mechanisms that produce this coloration are still poorly characterized, especially at the genomic level. Here we have taken a transcriptomics-based approach to elucidate the underlying genetic mechanisms affecting color and pattern in a highly polytypic poison frog. We sequenced RNA from the skin from four different color morphs during the final stage of metamorphosis and assembled a de novo transcriptome. We then investigated differential gene expression, with an emphasis on examining candidate color genes from other taxa. Results: Overall, we found differential expression of a suite of genes that control melanogenesis, melanocyte differentiation, and melanocyte proliferation (e.g., tyrp1, lef1, leo1, and mitf) as well as several differentially expressed genes involved in purine synthesis and iridophore development (e.g., arfgap1, arfgap2, airc, and gart). Conclusions: Our results provide evidence that several gene networks known to affect color and pattern in vertebrates play a role in color and pattern variation in this species of poison frog

    Correlation of pretreatment drug induced apoptosis in ovarian cancer cells with patient survival and clinical response

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    Background This study was performed to determine if a chemotherapy-induced apoptosis assay (MiCK) could predict the best therapy for patients with ovarian cancer. Methods A prospective, multi-institutional and blinded trial of the assay was conducted in 104 evaluable ovarian cancer patients treated with chemotherapy. The MiCK assay was performed prior to therapy, but treating physicians were not told of the results and selected treatment only on clinical criteria. Outcomes (response, time to relapse, and survival) were compared to the drug-induced apoptosis observed in the assay. Results Overall survival in primary therapy, chemotherapy naïve patients with Stage III or IV disease was longer if patients received a chemotherapy which was best in the MiCK assay, compared to shorter survival in patients who received a chemotherapy that was not the best. (p < 0.01, hazard ratio HR 0.23). Multivariate model risk ratio showed use of the best chemotherapy in the MiCK assay was the strongest predictor of overall survival (p < 0.01) in stage III or IV patients. Standard therapy with carboplatin plus paclitaxel (C + P) was not the best chemotherapy in the MiCK assay in 44% of patients. If patients received C + P and it was the best chemotherapy in the MiCK assay, they had longer survival than those patients receiving C + P when it was not the best chemotherapy in the assay (p = 0.03). Relapse-free interval in primary therapy patients was longer if patients received the best chemotherapy from the MiCK assay (p = 0.03, HR 0.52). Response rates (CR + PR) were higher if physicians used an active chemotherapy based on the MiCK assay (p = 0.03). Conclusion The MiCK assay can predict the chemotherapy associated with better outcomes in ovarian cancer patients. This study quantifies outcome benefits on which a prospective randomized trial can be developed
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