2,341 research outputs found

    The Role of MAPK and SCF in the Destruction of Med13 in Cyclin C Mediated Cell Death

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    In response to stress, the yeast1 and mammalian2 cyclin C translocate from the nucleus to the cytoplasm, where it associates with the GTPase Drp1/Dnm1 to drive mitochondrial fragmentation and apoptosis. Therefore, the decision to release cyclin C represents a key life or death decision. In unstressed cells, the cyclin C‐Cdk8 kinase regulates transcription by associating with the Mediator of RNA polymerase II. We previously reported that the Mediator component Med13 anchors cyclin C in the nucleus3. Loss of Med13 function leads to constitutive cytoplasmic localization of cyclin C, resulting in fragmented mitochondria, hypersensitivity to stress and mitochondrial dysfunction due to loss of mtDNA. Recently we showed that this molecular switch operates in a two-step process

    Chronic Exposure of Corals to Fine Sediments: Lethal and Sub-Lethal Impacts

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    Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS) for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata) more than the upright branching species (Acropora millepora). The lowest sediment treatments that caused full colony mortality were 30 mg lβˆ’1 TSS (25 mg cmβˆ’2 dayβˆ’1) for M. aequituberculata and 100 mg lβˆ’1 TSS (83 mg cmβˆ’2 dayβˆ’1) for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue

    The Web Epoch of Reionization Lyman-Ξ±\alpha Survey (WERLS) I. MOSFIRE Spectroscopy of z∼7βˆ’8\mathbf{z \sim 7-8} Lyman-Ξ±\alpha Emitters

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    We present the first results from the Web Epoch of Reionization Lyman-Ξ±\alpha Survey (WERLS), a spectroscopic survey of Lyman-Ξ±\alpha emission using Keck I/MOSFIRE and LRIS. WERLS targets bright (J<26J<26) galaxy candidates with photometric redshifts of 5.5≲z≲85.5\lesssim z \lesssim 8 selected from pre-JWST imaging embedded in the Epoch of Reionization (EoR) within three JWST deep fields: CEERS, PRIMER, and COSMOS-Web. Here, we report 11 z∼7βˆ’8z\sim7-8 Lyman-Ξ±\alpha emitters (LAEs; 3 secure and 8 tentative candidates) detected in the first five nights of WERLS MOSFIRE data. We estimate our observed LAE yield is ∼13\sim13%, broadly consistent with expectations assuming some loss from redshift uncertainty, contamination from sky OH lines, and that the Universe is approximately half-ionized at this epoch, whereby observable Lyman-Ξ±\alpha emission is unlikely for galaxies embedded in a neutral intergalactic medium. Our targets are selected to be UV-bright, and span a range of absolute UV magnitudes with βˆ’23.1<MUV<βˆ’19.8-23.1 < M_{\text{UV}} < -19.8. With two LAEs detected at z=7.68z=7.68, we also consider the possibility of an ionized bubble at this redshift. Future synergistic Keck+JWST efforts will provide a powerful tool for pinpointing beacons of reionization and mapping the large scale distribution of mass relative to the ionization state of the Universe.Comment: 27 pages, 8 figures; ApJ submitte

    Dendritic Cells as Danger-Recognizing Biosensors

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    Dendritic cells (DCs) are antigen presenting cells that are characterized by a potent capacity to initiate immune responses. DCs comprise several subsets with distinct phenotypes. After sensing any danger(s) to the host via their innate immune receptors such as Toll-like receptors, DCs become mature and subsequently present antigens to CD4+ T cells. Since DCs possess the intrinsic capacity to polarize CD4+ helper cells, it is critical to understand the immunological roles of DCs for clinical applications. Here, we review the different DC subsets, their danger-sensing receptors and immunological functions. Furthermore, the cytokine reporter mouse model for studying DC activation is introduced
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