46 research outputs found

    As old as the hills: Pliocene palaeogeographical processes influence patterns of genetic structure in the widespread, common shrub Banksia sessilis

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    The impact of Quaternary glaciation on the development of phylogeographic structure in plant species is well documented. In unglaciated landscapes, phylogeographic patterns tend to reflect processes relating to persistence and stochasticity, yet other factors, associated with the palaeogeographical history of the landscape, including geomorphological events, can also have a significant influence. The unglaciated landscape of south‐western Western Australia is an ideal location to observe these ancient drivers of lineage diversification, with tectonic activity associated with the Darling Fault in the late Pliocene attributed to patterns of deep phylogeographic divergence in a widespread tree from this region. Interestingly, other species within this region have not shown this pattern and this palaeogeographical boundary therefore presents an opportunity to examine age and historical distribution of plant species endemic to this region. In this study, we assess patterns of genetic diversity and structure across 28 populations of the widespread shrub Banksia sessilis using three cpDNA markers and nine nuclear microsatellite markers. Sixteen cpDNA haplotypes were identified, comprising two major chloroplast DNA lineages that are estimated to have diverged in the Pliocene, approximately 3.3 million years ago. This timing coincides with major geomorphological processes in the landscape, including the separation of the Darling Plateau from the adjacent Swan Coastal Plain, as well as eustatic changes on the Swan Coastal Plain that are likely to have resulted in the physical isolation of historical plant lineages. Chloroplast lineages were broadly aligned with populations associated with older lateritic soils of the Darling Plateau and Geraldton sandplains or the younger sandy soils associated with the Swan Coastal Plain and Southern Coastline. This structural pattern of lateritic versus non‐lateritic division was not observed in the nuclear microsatellite data that identified three genetic clades that roughly corresponded to populations in the North, South, and Central portions of the distributions

    Localization of Quaternary slip rates in an active rift in 10(5) years: an example from central Greece constrained by U-234-Th-230 coral dates from uplifted paleoshorelines

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    Mapping, dating, and modeling of paleoshorelines uplifted in the footwall of the 1981 Gulf of Corinth earthquake fault, Greece (Ms 6.9–6.7), are used to assess its slip rate history relative to other normal faults in the area and study strain localization. The 234U-230Th coral ages from Cladocora caespitosa date uplifted shoreface sediments, and paleoshorelines from glacioeustatic sea level highstands at 76, (possibly) 100, 125, 175, 200, 216, 240, and 340 ka. Uplifted Quaternary and Holocene paleoshorelines decrease in elevation toward the western tip of the fault, exhibiting larger tilt angles with age, showing that uplift is due to progressive fault slip. Since 125 ka, uplift rates varied from 0.25 to 0.52 mm/yr over a distance of 5 km away from the fault tip. Tilting was also occurring prior to 125 ka, but uplift rates were lower because the 125 ka paleoshoreline is at 77% of the elevation of the 240 ka paleoshoreline despite being nearly half its age. Comparison of paleoshoreline elevations and sedimentology with the Quaternary sea level curve shows that slip rates increased by a factor of 3.2 ± 0.2 at 175 ± 75 ka, synchronous with cessation of activity on a neighboring normal fault at 382–112 ka. We suggest that the rapid localization of up to 10–15 mm/yr of extension into the narrow gulf (∌30 km wide) resulted from synchronous fault activity on neighboring faults followed by localization rather than sequential faulting, with consequences for the mechanism controlling localization of extension

    The Mitochondrial Apoptotic Effectors BAX/BAK Activate Caspase-3 and -7 to Trigger NLRP3 Inflammasome and Caspase-8 Driven IL-1beta Activation

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    Published: November 27, 2018Intrinsic apoptosis resulting from BAX/BAK-mediated mitochondrial membrane damage is regarded as immunologically silent. We show here that in macrophages, BAX/BAK activation results in inhibitor of apoptosis (IAP) protein degradation to promote caspase-8-mediated activation of IL-1ÎČ. Furthermore, BAX/BAK signaling induces a parallel pathway to NLRP3 inflammasome-mediated caspase-1-dependent IL-1ÎČ maturation that requires potassium efflux. Remarkably, following BAX/BAK activation, the apoptotic executioner caspases, caspase-3 and -7, act upstream of both caspase-8 and NLRP3-induced IL-1ÎČ maturation and secretion. Conversely, the pyroptotic cell death effectors gasdermin D and gasdermin E are not essential for BAX/BAK-induced IL-1ÎČ release. These findings highlight that innate immune cells undergoing BAX/BAK-mediated apoptosis have the capacity to generate pro-inflammatory signals and provide an explanation as to why IL-1ÎČ activation is often associated with cellular stress, such as during chemotherapy.James E. Vince, Dominic De Nardo, Wenqing Gao, Angelina J. Vince, Cathrine Hall, Kate McArthur, Daniel Simpson, Swarna Vijayaraj, Lisa M. Lindqvist, Philippe Bouillet, Mark A. Rizzacasa, Si Ming Man, John Silke, Seth L. Masters, Guillaume Lessene, David C.S. Huang, Daniel H.D. Gray, Benjamin T. Kile, Feng Shao, and Kate E. Lawlo

    Clinical utilization of genomics data produced by the international Pseudomonas aeruginosa consortium

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    The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection, are available through the International Pseudomonas Consortium Database (http://ipcd.ibis.ulaval.ca/). Here, we present our strategy and the results that emerged from the analysis of the first 389 genomes. With as yet unmatched resolution, our results confirm that P. aeruginosa strains can be divided into three major groups that are further divided into subgroups, some not previously reported in the literature. We also provide the first snapshot of P. aeruginosa strain diversity with respect to antibiotic resistance. Our approach will allow us to draw potential links between environmental strains and those implicated in human and animal infections, understand how patients become infected and how the infection evolves over time as well as identify prognostic markers for better evidence-based decisions on patient care

    Oncogenic Signaling Pathways in The Cancer Genome Atlas

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    Genetic alterations in signaling pathways that control cell-cycle progression, apoptosis, and cell growth are common hallmarks of cancer, but the extent, mechanisms, and co-occurrence of alterations in these pathways differ between individual tumors and tumor types. Using mutations, copy-number changes, mRNA expression, gene fusions and DNA methylation in 9,125 tumors profiled by The Cancer Genome Atlas (TCGA), we analyzed the mechanisms and patterns of somatic alterations in ten canonical pathways: cell cycle, Hippo, Myc, Notch, Nrf2, PI-3-Kinase/Akt, RTK-RAS, TGFb signaling, p53 and beta-catenin/Wnt. We charted the detailed landscape of pathway alterations in 33 cancer types, stratified into 64 subtypes, and identified patterns of co-occurrence and mutual exclusivity. Eighty-nine percent of tumors had at least one driver alteration in these one alteration potentially targetable by currently available drugs. Thirty percent of tumors had multiple targetable alterations, indicating opportunities for combination therapy

    Cytokine genotype suggests a role for inflammation in nucleoside analog-associated sensory neuropathy (NRTI-SN) and predicts an individual's NRTI-SN risk

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    Nucleoside analog-associated sensory neuropathy (NRTI-SN) attributed to stavudine, didanosine, or zalcitabine (the dNRTIs) and distal sensory polyneuropathy (DSP) attributed to HIV are clinically indistinguishable. As inflammatory cytokines are involved in DSP, we addressed a role for inflammation in NRTI-SN by determining the alleles of immune-related genes carried by patients with and without NRTI-SN. Demographic details associated with risk of various neuropathies were included in the analysis. Alleles of 14 polymorphisms in 10 genes were determined in Australian HIV patients with definite NRTI-SN (symptom onset 6 months on dNRTIs, n = 20), patients with late onset NRTI-SN (neuropathy onset after >6 months of dNRTIs, n = 19), and HIV-negative controls. Carriage of TNFA-1031*2 was highest in NRTI-SN patients, suggesting potentiation of NRTI-SN. Carriage of IL12B (3â€Č UTR)*2 was higher in NRTI-SN-resistant patients than controls or NRTI-SN patients, suggesting a protective role. BAT1 (intron 10)*2 was more common in NRTI-SN than resistant patients, but neither group differed from controls. This marks the conserved HLA-A1, B8, DR3 haplotype. Of the demographic details considered, increasing height was associated with NRTI-SN risk. A model including cytokine genotype and height predicted NRTI-SN status (p < 0.0001, R 2 = 0.54). Late onset NRTI-SN patients clustered genetically with NRTI-SN-resistant patients, so these patients may be genetically "protected." In addition to patient height, cytokine genotype influenced NRTI-SN risk following dNRTI exposure, suggesting inflammation contributes to NRTI-SN

    In situ monitoring of the effect of ionic strength and pH on plasma polymer thin films

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    The effect of ionic strength and pH on the structure of hydrated plasma polymerized films of allylamine (ppAAm) and acrylic acid (ppAAc) has been analyzed in situ using quartz crystal microbalance with dissipation techniques, electrochemical impedance spectroscopy, ellipsomtery, and X‐ray photoelectron spectroscopy. Both materials showed a salt concentration and pH dependent uptake and release of water and ions. Depending on the type of monomer used, the effects showed reversible or non‐reversible behavior. The investigation of the electrochemical properties of the film further revealed a non‐homogeneous structure, especially in the case of ppAAc films, with regions of higher and lower cross‐linking density. The use of complimentary techniques to characterize the films in situ allowed for a deeper understanding of processes happening inside the plasma polymerized films, which can help to optimize film preparation conditions for selected applications

    Tissue-specific associations between mitochondrial DNA levels and current treatment status in HIV-Infected individuals

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    Background: Tissue mitochondrial DNA (mtDNA) levels have been proposed as a marker of nucleoside analouge reverse transcriptase inhibitor (NRTI) toxicity. However, clinical studies have yielded conflicting data regarding possible associations with mtDNA levels. This study examined mtDNA levels in matched samples of peripheral blood mononuclear cells (PBMCs) and subcutaneous fat from a large Australian cohort to examine treatment, clinical, and demographic associations with mtDNA depletion. Methods: mtDNA was quantified by real-time polymerase chain reaction. Results were compared across patient treatment and demographic details using linear mixed models. Results: One hundred sixty-three PBMCs and 161 fat samples were available from 61 individuals. Current NRTI exposure was the major determinant of mtDNA levels. Both ddI (didanosine) and d4T (stavudine) exposures were associated with mtDNA depletion in fat (P <= 0.0001 vs. those not on NRTIs). DdI exposure (P = 0.003), but not d4T exposure (P = 0.5), was associated with mtDNA depletion in PBMCs. No association between patient demographics or time on current therapy and mtDNA was observed. Conclusions: Current NRTI exposure is the major determinant of tissue mtDNA, but the precise determinants are tissue specific. Both ddI and d4T exposure are associated with fat mtDNA depletion, whereas ddI exposure was the only observed association with mtDNA depletion in PBMCs
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