391 research outputs found

    Soluble tumor necrosis factor receptor 1 and 2 predict outcomes in advanced chronic kidney disease : a prospective cohort study

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    Background : Soluble tumor necrosis factor receptors 1 (sTNFR1) and 2 (sTNFR2) have been associated to progression of renal failure, end stage renal disease and mortality in early stages of chronic kidney disease (CKD), mostly in the context of diabetic nephropathy. The predictive value of these markers in advanced stages of CKD irrespective of the specific causes of kidney disease has not yet been defined. In this study, the relationship between sTNFR1 and sTNFR2 and the risk for adverse cardiovascular events (CVE) and all-cause mortality was investigated in a population with CKD stage 4-5, not yet on dialysis, to minimize the confounding by renal function. Patients and methods : In 131 patients, CKD stage 4-5, sTNFR1, sTNFR2 were analysed for their association to a composite endpoint of all-cause mortality or first non-fatal CVE by univariate and multivariate Cox proportional hazards models. In the multivariate models, age, gender, CRP, eGFR and significant comorbidities were included as covariates. Results : During a median follow-up of 33 months, 40 events (30.5%) occurred of which 29 deaths (22.1%) and 11 (8.4%) first non-fatal CVE. In univariate analysis, the hazard ratios (HR) of sTNFR1 and sTNFR2 for negative outcome were 1.49 (95% confidence interval (CI): 1.28-1.75) and 1.13 (95% CI: 1.06-1.20) respectively. After adjustment for clinical covariables (age, CRP, diabetes and a history of cardiovascular disease) both sTNFRs remained independently associated to outcomes (HR: sTNFR1: 1.51, 95% CI: 1.30-1.77; sTNFR2: 1.13, 95% CI: 1.06-1.20). A subanalysis of the non-diabetic patients in the study population confirmed these findings, especially for sTNFR1. Conclusion : sTNFR1 and sTNFR2 are independently associated to all-cause mortality or an increased risk for cardiovascular events in advanced CKD irrespective of the cause of kidney disease

    Trisomy of a Down Syndrome Critical Region Globally Amplifies Transcription via HMGN1 Overexpression

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    Down syndrome (DS, trisomy 21) is associated with developmental abnormalities and increased leukemia risk. To reconcile chromatin alterations with transcriptome changes, we performed paired exogenous spike-in normalized RNA and chromatin immunoprecipitation sequencing in DS models. Absolute normalization unmasks global amplification of gene expression associated with trisomy 21. Overexpression of the nucleosome binding protein HMGN1 (encoded on chr21q22) recapitulates transcriptional changes seen with triplication of a Down syndrome critical region on distal chromosome 21, and HMGN1 is necessary for B cell phenotypes in DS models. Absolute exogenous-normalized chromatin immunoprecipitation sequencing (ChIP-Rx) also reveals a global increase in histone H3K27 acetylation caused by HMGN1. Transcriptional amplification downstream of HMGN1 is enriched for stage-specific programs of B cells and B cell acute lymphoblastic leukemia, dependent on the developmental cellular context. These data offer a mechanistic explanation for DS transcriptional patterns and suggest that further study of HMGN1 and RNA amplification in diverse DS phenotypes is warranted. How trisomy 21 contributes to Down syndrome phenotypes, including increased leukemia risk, is not well understood. Mowery et al. use per-cell normalization approaches to reveal global transcriptional amplification in Down syndrome models. HMGN1 overexpression is sufficient to induce these alterations and promotes lineage-associated transcriptional programs, signaling, and B cell progenitor phenotypes

    Conceptual Frameworks and Methods for Advancing Invasion Ecology

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    Invasion ecology has much advanced since its early beginnings. Nevertheless, explanation, prediction, and management of biological invasions remain difficult. We argue that progress in invasion research can be accelerated by, first, pointing out difficulties this field is currently facing and, second, looking for measures to overcome them. We see basic and applied research in invasion ecology confronted with difficulties arising from (A) societal issues, e.g., disparate perceptions of invasive species; (B) the peculiarity of the invasion process, e.g., its complexity and context dependency; and (C) the scientific methodology, e.g., imprecise hypotheses. To overcome these difficulties, we propose three key measures: (1) a checklist for definitions to encourage explicit definitions; (2) implementation of a hierarchy of hypotheses (HoH), where general hypotheses branch into specific and precisely testable hypotheses; and (3) platforms for improved communication. These measures may significantly increase conceptual clarity and enhance communication, thus advancing invasion ecology

    Endophytes vs tree pathogens and pests: can they be used as biological control agents to improve tree health?

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    Like all other plants, trees are vulnerable to attack by a multitude of pests and pathogens. Current control measures for many of these diseases are limited and relatively ineffective. Several methods, including the use of conventional synthetic agro-chemicals, are employed to reduce the impact of pests and diseases. However, because of mounting concerns about adverse effects on the environment and a variety of economic reasons, this limited management of tree diseases by chemical methods is losing ground. The use of biological control, as a more environmentally friendly alternative, is becoming increasingly popular in plant protection. This can include the deployment of soil inoculants and foliar sprays, but the increased knowledge of microbial ecology in the phytosphere, in particular phylloplane microbes and endophytes, has stimulated new thinking for biocontrol approaches. Endophytes are microbes that live within plant tissues. As such, they hold potential as biocontrol agents against plant diseases because they are able to colonize the same ecological niche favoured by many invading pathogens. However, the development and exploitation of endophytes as biocontrol agents will have to overcome numerous challenges. The optimization and improvement of strategies employed in endophyte research can contribute towards discovering effective and competent biocontrol agents. The impact of environment and plant genotype on selecting potentially beneficial and exploitable endophytes for biocontrol is poorly understood. How endophytes synergise or antagonise one another is also an important factor. This review focusses on recent research addressing the biocontrol of plant diseases and pests using endophytic fungi and bacteria, alongside the challenges and limitations encountered and how these can be overcome. We frame this review in the context of tree pests and diseases, since trees are arguably the most difficult plant species to study, work on and manage, yet they represent one of the most important organisms on Earth

    Diversity of Staphylococcus aureus associated with mastitis from dairy cows in Rwanda

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    Objectives The objective of the present study was to examine the diversity of Staphylococcus aureus from mastitis milk samples of cows in Rwanda. Methods A total of 1080 quarter milk samples from 279 dairy cows were collected in 80 different farms from all five provinces of Rwanda. In total, 135 S. aureus isolates were obtained and subjected to genotyping (spa typing, DNA microarray, whole-genome sequencing (WGS)), antimicrobial susceptibility testing (AST) and phenotypic profiling by Fourier Transform Infrared (FTIR) spectroscopy (including capsular serotyping). Results Resistance to penicillin and/or tetracycline was most frequently observed. Ten sequence types (STs) (ST1, ST151, ST152, ST5477, ST700, ST7110, ST7983, ST7984, ST8320, ST97) belonging to seven clonal complexes (CCs) (CC1, CC130, CC152, CC3591, CC3666, CC705, CC97) were detected. The Panton–Valentine leukocidin (PVL) genes (lukF-PV/lukS-PV), the bovine leukocidin genes (lukM/lukF-P83) and the human and bovine toxic shock syndrome toxin gene tst-1 variants were detected. FTIR-based capsular serotyping showed CC-specific differences. Most CC97 (cap5 allele) isolates were primarily nonencapsulated (82%), whereas isolates of CC3591 and CC3666 (cap8 allele) were mostly encapsulated (86.4% and 57.8%, respectively). Our results underline the widespread global distribution of cattle-adapted CC97. Conclusion The presence of CC3591 and CC3666 in bovine mastitis suggests an important role in cattle health and dairy production in Rwanda. The results of the present study support the need for a rigorous One-Health Surveillance program of the bovine–human interface

    Staphylococcus aureus in Rwandan dogs predominantly representing human-associated lineages

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    The present study aimed at examining the nasal and ear carriage of Staphylococcus aureus of Rwandan dogs and cats. Sixty-five S. aureus isolates were detected, all originating from the nostrils of dogs. Resistance to penicillin, penicillin/erythromycin/clindamycin, penicillin/tetracycline, and tetracycline solely was observed. The isolates were assigned to 23 different spa types, among them three novel (t21589, t21661, and t21662) variants, associated with eleven clonal complexes (CCs) (CC1, CC5, CC12, CC15, CC22, CC30, CC45, CC97, CC152, CC707, and CC834). Four isolates could not be assigned to any known CC. MLST revealed that one of them belonged to the new sequence type (ST) 9069. Panton–Valentine leukocidin (PVL) genes (lukF-PV/lukS-PV), the bovine leukocidin genes (lukM/lukF-P83), the toxic shock syndrome toxin gene tst-1, and various virulence-associated genes were detected. These findings demonstrate the dogs are colonized with human lineages of S. aureus. Coupled with the limited availability of S. aureus data from human medicine in Rwanda underscores the importance of hygiene measures and supports the need for a rigorous One-Health Surveillance program of the companion animals–human interface

    Multiple plant traits shape the genetic basis of herbivore community assembly

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    1. Community genetics research has posited a genetic basis to the assembly of ecological communities. For arthropod herbivores in particular, there is strong support that genetic variation in host plants is a key factor shaping their diversity and composition. However, the specific plant phenotypes underlying herbivore responses remain poorly explored for most systems. 2. We address this knowledge gap by examining the influence of both genetic and phenotypic variation in a dominant host-plant species, Salix hookeriana, on its associated arthropod herbivore community in a common garden experiment. Specifically, we surveyed herbivore responses among five different arthropod feeding guilds to 26 distinct S. hookeriana genotypes. Moreover, we quantified the heritability of a suite of plant traits that determine leaf quality (e.g. phenolic compounds, trichomes, specific leaf area, C : N) and whole-plant architecture, to identify which traits best accounted for herbivore community responses to S. hookeriana genotype. 3. We found that total herbivore abundance and community composition differed considerably among S. hookeriana genotypes, with strong and independent responses of several species and feeding guilds driving these patterns. We also found that leaf phenolic chemistry displayed extensive heritable variation, whereas leaf physiology and plant architecture tended to be less heritable. Of these traits, herbivore responses were primarily associated with leaf phenolics and plant architecture; however, different herbivore species and feeding guilds were associated with different sets of traits. Despite our thorough trait survey, plant genotype remained a significant predictor of herbivore responses in most trait association analyses, suggesting that unmeasured host-plant characteristics and/or interspecific interactions were also contributing factors. 4. Taken together, our results support that the genetic basis of herbivore community assembly occurs through a suite of plant traits for different herbivore species and feeding guilds. Still, identifying these phenotypic mechanisms requires measuring a broad range of plant traits and likely further consideration of how these traits affect interspecific interactions.Fil: Barbour, Matthew A.. University Of British Columbia; CanadáFil: Rodriguez Cabal, Mariano Alberto. University Of British Columbia; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Wu, Elizabeth T.. Humboldt State University; Estados UnidosFil: Julkunen Tiitto, Riitta. University of Eastern Finland; FinlandiaFil: Ritland, Carol E.. University Of British Columbia; CanadáFil: Miscampbell, Allyson E.. University Of British Columbia; CanadáFil: Jules, Erik S.. Humboldt State University; Estados UnidosFil: Crutsinger, Gregory M.. University Of British Columbia; Canad

    New insights into the neolithisation process in southwest Europe according to spatial density analysis from calibrated radiocarbon dates

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    The agricultural way of life spreads throughout Europe via two main routes: the Danube corridor and the Mediterranean basin. Current archaeological literature describes the arrival to the Western Mediterranean as a rapid process which involves both demic and cultural models, and in this regard, the dispersal movement has been investigated using mathematical models, where the key factors are time and space. In this work, we have created a compilation of all available radiocarbon dates for the whole of Iberia, in order to draw a chronological series of maps to illustrate temporal and spatial patterns in the neolithisation process. The maps were prepared by calculating the calibrated 14C date probability density curves, as a proxy to show the spatial dynamics of the last hunter-gatherers and first farmers. Several scholars have pointed out problems linked with the variability of samples, such as the overrepresentation of some sites, the degree of regional research, the nature of the dated samples and above all the archaeological context, but we are confident that the selected dates, after applying some filters and statistical protocols, constitute a good way to approach settlement spatial patterns in Iberia at the time of the neolithisation process

    Molecular characterization, virulence and antimicrobial and biocidal susceptibility of selected bacteria isolated from the cloaca of nestling ospreys (Pandion haliaetus) from Mono Lake, California, USA

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    In the present study, the presence of the Enterobacterales, Staphylococcus spp., Mammaliicoccus spp., and Enterococcus spp. in cloacal samples of nestling ospreys (Pandion haliaetus), a fish-eating specialist, from Mono Lake, California, USA was examined by a multiphasic approach, including antimicrobial and biocide susceptibility testing, genotyping, and whole genome sequencing of selected isolates. The most commonly detected species was Escherichia coli, followed by Mammaliicoccus sciuri, Staphylococcus delphini, Enterococcus faecalis, Enterococcus faecium, Hafnia alvei, Klebsiella pneumoniae, Citrobacter braakii and single isolates of Edwardsiella tarda, Edwardsiella albertii, Klebsiella aerogenes, Plesiomonas shigelloides and Staphylococcus pseudintermedius. Multi-drug resistance (MDR) was observed in two E. coli isolates and in an Enterococcus faecium isolate. The MDR blaCTX-M-55-positive E. coli belonged to the pandemic clone ST58. The results of the present study suggest that nestling ospreys are exposed to MDR bacteria, possibly through the ingestion of contaminated fish. Ospreys may be good biosentinels for the presence of these microorganisms and antibiotic resistance in the local environment and the risk for other wildlife, livestock and humans
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