407 research outputs found

    Environment, vector, or host? Using machine learning to untangle the mechanisms driving arbovirus outbreaks

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    Climatic, landscape, and host features are critical components in shaping out-breaks of vector-borne diseases. However, the relationship between the outbreaks of vector-borne pathogens and their environmental drivers is typically complicated, nonlinear, and mayvary by taxonomic units below the species level (e.g., strain or serotype). Here, we aim tountangle how these complex forces shape the risk of outbreaks of Bluetongue virus (BTV); avector-borne pathogen that is continuously emerging and re-emerging across Europe, with sev-ere economic implications. We tested if the ecological predictors of BTV outbreak risk wereserotype-specific by examining the most prevalent serotypes recorded in Europe (1, 4, and 8).We used a robust machine learning (ML) pipeline and 23 relevant environmental features to fitpredictive models to 24,245 outbreaks reported in 25 European countries between 2000 and2019. Our ML models demonstrated high predictive performance for all BTV serotypes (accu-racies>0.87) and revealed strong nonlinear relationships between BTV outbreak risk andenvironmental and host features. Serotype-specific analysis suggests, however, that each of themajor serotypes (1, 4, and 8) had a unique outbreak risk profile. For example, temperature andmidge abundance were as the most important characteristics shaping serotype 1, whereas forserotype 4 goat density and temperature were more important. We were also able to identifystrong interactive effects between environmental and host characteristics that were also sero-type specific. Our ML pipeline was able to reveal more in-depth insights into the complex epi-demiology of BTVs and can guide policymakers in intervention strategies to help reduce theeconomic implications and social cost of this important pathogen

    Manifestaciones orales en pacientes con diabetes mellitus tipo 2 atendidos en el Hospital Alberto Sabogal

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    Objective: To determine the most frequent oral manifestations of type 2 diabetes mellitus patients at the Sabogal Hospital during 2016. Methods: Descriptive, cross-sectional study. 47 patients were evaluated with an age range of <40 years, 40-65 years and > = 65 years and in the female / male ratio was 1/1, with type 2 diabetes mellitus from the Sabogal Hospital during October, 2016. Data were collected with a chart that included socio-demographic variables of the patients and oral cavity examinations. The statistical analysis was frequency distribution and association of variables with chi-square analysis. Results: The most frequent age group was, patients over 65 years of age (48.94%). Arterial hypertension was the most frequent comorbidity with 57.45% and retinopathy as a chronic complication with 42.55%. From the sample 63.83% were insulin-dependent. The most frequent oral manifestation was partial edentulism with 85.11%, followed by caries with 82.98%, 78.72% gingivitis,Objetivo: Determinar las manifestaciones orales más frecuentes de la diabetes mellitus tipo 2 durante el año 2016 en el Hospital Alberto Sabogal. Materiales y Métodos: Estudio descriptivo, transversal. Se evaluó a 47 pacientes con un rango de edades de < 40 años, 40 – 65 años y >= 65 años y en cuanto a razón femenina/masculino fue de 1/1, con diabetes mellitus tipo 2 del Hospital Sabogal, octubre de 2016. Los datos se recolectaron con una ficha que incluía variables sociodemográficas de los pacientes y evaluación de la cavidad oral. El análisis estadístico fue de distribución de frecuencias y de asociación de variables con chi2. Resultados: El grupo etario más frecuente fue el de mayores de65 años (48,94%). La hipertensión arterial fue la comorbilidad más frecuente (57,45%) y la retinopatía como complicación crónica (42,55%). El 63,83% usaba insulina. La manifestación oral más frecuente fue edentulismo parcial (85,11%), seguido de caries (82,98%), gingivitis (78,72%), p

    New Hybrid Properties of TiO2 Nanoparticles Surface Modified With Catecholate Type Ligands

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    Surface modification of nanocrystalline TiO2 particles (45 Å) with bidentate benzene derivatives (catechol, pyrogallol, and gallic acid) was found to alter optical properties of nanoparticles. The formation of the inner-sphere charge–transfer complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites. The binding structures were investigated by using FTIR spectroscopy. The investigated ligands have the optimal geometry for chelating surface Ti atoms, resulting in ring coordination complexes (catecholate type of binuclear bidentate binding–bridging) thus restoring in six-coordinated octahedral geometry of surface Ti atoms. From the Benesi–Hildebrand plot, the stability constants at pH 2 of the order 103 M−1 have been determined

    Cloning of somatolactin alpha, beta forms and the somatolactin receptor in Atlantic salmon: Seasonal expression profile in pituitary and ovary of maturing female broodstock

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    <p>Abstract</p> <p>Background</p> <p>Somatolactin (Sl) is a fish specific adenohypophyseal peptide hormone related to growth hormone (Gh). Some species, including salmonids, possess two forms: Sl alpha and Sl beta. The somatolactin receptor (slr) is closely related to the growth hormone receptor (ghr). Sl has been ascribed many physiological functions, including a role in sexual maturation. In order to clarify the role of Sl in the sexual maturation of female Atlantic salmon (Salmo salar), the full length cDNAs of slr, Sl alpha and Sl beta were cloned and their expression was studied throughout a seasonal reproductive cycle using real-time quantitative PCR (RTqPCR).</p> <p>Methods</p> <p>Atlantic salmon Sl alpha, Sl beta and slr cDNAs were cloned using a PCR approach. Gene expression of Sl alpha, SL beta and slr was studied using RTqPCR over a 17 month period encompassing pre-vitellogenesis, vitellogenesis, ovulation and post ovulation in salmon females. Histological examination of ovarian samples allowed for the classification according to the degree of follicle maturation into oil drop, primary, secondary or tertiary yolk stage.</p> <p>Results</p> <p>The mature peptide sequences of Sl alpha, Sl beta and slr are highly similar to previously cloned salmonid forms and contained the typical motifs. Phylogenetic analysis of Atlantic salmon Sl alpha and Sl beta shows that these peptides group into the two Sl clades present in some fish species. The Atlantic salmon slr grouped with salmonid slr amongst so-called type I ghr. An increase in pituitary Sl alpha and Sl beta transcripts before and during spawning, with a decrease post-ovulation, and a constant expression level of ovarian slr were observed. There was also a transient increase in Sl alpha and Sl beta in May prior to transfer from seawater to fresh water and ensuing fasting.</p> <p>Conclusion</p> <p>The up-regulation of Sl alpha and Sl beta during vitellogenesis and spawning, with a subsequent decrease post-ovulation, supports a role for Sl during gonadal growth and spawning. Sl could also be involved in calcium/phosphate mobilization associated with vitellogenesis or have a role in energy homeostasis associated with lipolysis during fasting. The up-regulation of both Sl alpha and Sl beta prior to fasting and freshwater transfer, suggests a role for Sl linked to reproduction that may be independent of the maturation induced fasting.</p

    Detrimental effects of tropisetron on permanent ischemic stroke in the rat

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    <p>Abstract</p> <p>Background</p> <p>Recent <it>in vitro </it>evidence indicates that blockade of 5-hydroxytryptamine (5-HT) receptor 3 (5-HT<sub>3</sub>) is able to confer protection in different models of neuronal injury. The purpose of the present study was to investigate the effect of tropisetron, a 5-HT<sub>3 </sub>receptor antagonist, on infarct size and neurological score in a model of ischemic stroke induced by permanent middle cerebral artery occlusion (pMCAO) in the rat.</p> <p>Methods</p> <p>Two different doses of tropisetron (5 and 10 mg/kg) or vehicle were administered intraperitoneally 30 min before pMCAO. Neurological deficit scores, mortality rate and infarct volume were determined 24 h after permanent focal cerebral ischemia.</p> <p>Results</p> <p>Tropisetron failed to reduce cerebral infarction. Animals receiving tropisetron showed a significant increase (p < 0.05) in neurological deficits and mortality rate.</p> <p>Conclusion</p> <p>Data from this study indicate that blockade of 5-HT<sub>3 </sub>receptors with tropisetron worsens ischemic brain injury induced by pMCAO. These findings could have important clinical implications. Patients taking tropisetron, and possibly other 5-HT<sub>3 </sub>antagonists, could potentially have a worse outcome following a brain infarct.</p

    Synchronized Retrovirus Fusion in Cells Expressing Alternative Receptor Isoforms Releases the Viral Core into Distinct Sub-cellular Compartments

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    Disparate enveloped viruses initiate infection by fusing with endosomes. However, the highly diverse and dynamic nature of endosomes impairs mechanistic studies of fusion and identification of sub-cellular sites supporting the nucleocapsid release. We took advantage of the extreme stability of avian retrovirus-receptor complexes at neutral pH and of acid-dependence of virus-endosome fusion to isolate the latter step from preceding asynchronous internalization/trafficking steps. Viruses were trapped within endosomes in the presence of NH4Cl. Removal of NH4Cl resulted in a quick and uniform acidification of all subcellular compartments, thereby initiating synchronous viral fusion. Single virus imaging demonstrated that fusion was initiated within seconds after acidification and often culminated in the release of the viral core from an endosome. Comparative studies of cells expressing either the transmembrane or GPI-anchored receptor isoform revealed that the transmembrane receptor delivered the virus to more fusion-permissive compartments. Thus the identity of endosomal compartments, in addition to their acidity, appears to modulate viral fusion. A more striking manifestation of the virus delivery to distinct compartments in the presence of NH4Cl was the viral core release into the cytosol of cells expressing the transmembrane receptor and into endosomes of cells expressing the GPI-anchored isoform. In the latter cells, the newly released cores exhibited restricted mobility and were exposed to a more acidic environment than the cytoplasm. These cores appear to enter into the cytosol after an additional slow temperature-dependent step. We conclude that the NH4Cl block traps the virus within intralumenal vesicles of late endosomes in cells expressing the GPI-anchored receptor. Viruses surrounded by more than one endosomal membrane release their core into the cytoplasm in two steps – fusion with an intralumenal vesicle followed by a yet unknown temperature-dependent step that liberates the core from late endosomes

    Evolution of metabolic divergence in <i>Pseudomonas aeruginosa</i> during long-term infection facilitates a proto-cooperative interspecies interaction

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    The effect of polymicrobial interactions on pathogen physiology and how it can act either to limit pathogen colonization or to potentiate pathogen expansion and virulence are not well understood. Pseudomonas aeruginosa and Staphylococcus aureus are opportunistic pathogens commonly found together in polymicrobial human infections. However, we have previously shown that the interactions between these two bacterial species are strain dependent. Whereas P. aeruginosa PAO1, a commonly used laboratory strain, effectively suppressed S. aureus growth, we observed a commensal-like interaction between the human host-adapted strain, DK2-P2M24-2003, and S. aureus. In this study, characterization by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) imaging mass spectrometry (IMS) and mass spectral (MS) molecular networking revealed a significant metabolic divergence between P. aeruginosa PAO1 and DK2-P2M24-2003, which comprised several virulence factors and signaling 4-hydroxy-2-alkylquinoline (HAQ) molecules. Strikingly, a further modulation of the HAQ profile was observed in DK2-P2M24-2003 during interaction with S. aureus, resulting in an area with thickened colony morphology at the P. aeruginosa–S. aureus interface. In addition, we found an HAQ-mediated protection of S. aureus by DK2-P2M24-2003 from the killing effect of tobramycin. Our findings suggest a model where the metabolic divergence manifested in human host-adapted P. aeruginosa is further modulated during interaction with S. aureus and facilitate a proto-cooperative P. aeruginosa–S. aureus relationship

    The route to transcription initiation determines the mode of transcriptional bursting in E. coli

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    Transcription is fundamentally noisy, leading to significant heterogeneity across bacterial populations. Noise is often attributed to burstiness, but the underlying mechanisms and their dependence on the mode of promotor regulation remain unclear. Here, we measure E. coli single cell mRNA levels for two stress responses that depend on bacterial sigma factors with different mode of transcription initiation (σ70 and σ54). By fitting a stochastic model to the observed mRNA distributions, we show that the transition from low to high expression of the σ70-controlled stress response is regulated via the burst size, while that of the σ54-controlled stress response is regulated via the burst frequency. Therefore, transcription initiation involving σ54 differs from other bacterial systems, and yields bursting kinetics characteristic of eukaryotic systems
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