3,887 research outputs found
The population structure of Pseudomonas aeruginosa is characterized by genetic isolation of exoU+ and exoS+ lineages
The diversification of microbial populations may be driven by many factors including adaptation to distinct ecological niches and barriers to recombination. We examined the population structure of the bacterial pathogen Pseudomonas aeruginosa by analyzing whole-genome sequences of 739 isolates from diverse sources. We confirmed that the population structure of P. aeruginosa consists of two major groups (referred to as Groups A and B) and at least two minor groups (Groups C1 and C2). Evidence for frequent intra-group but limited inter-group recombination in the core genome was observed, consistent with sexual isolation of the groups. Likewise, accessory genome analysis demonstrated more gene flow within Groups A and B than between these groups, and a few accessory genomic elements were nearly specific to one or the other group. In particular, the exoS gene was highly over-represented in Group A compared to Group B isolates (99.4% vs. 1.1%) and the exoU gene was highly over-represented in Group B compared to Group A isolates (95.2% vs. 1.8%). The exoS and exoU genes encode effector proteins secreted by the P. aeruginosa type III secretion system. Together these results suggest that the major P. aeruginosa groups defined in part by the exoS and exoU genes are divergent from each other, and that these groups are genetically isolated and may be ecologically distinct. Although both groups were globally distributed and caused human infections, certain groups predominated in some clinical contexts
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Exposure to Bisphenol A and Other Phenols in Neonatal Intensive Care Unit Premature Infants
Objective: We previously demonstrated that exposure to polyvinyl chloride plastic medical devices containing di(2-ethylhexyl) phthalate (DEHP) was associated with higher urinary concentrations of several DEHP metabolites in 54 premature infants in two neonatal intensive care units than in the general population. For 42 of these infants, we evaluated urinary concentrations of several phenols, including bisphenol A (BPA), in association with the use of the same medical devices. Measurements: We measured the urinary concentrations of free and total (free plus conjugated) species of BPA, triclosan, benzophenone-3, methyl paraben, and propyl paraben. Results: The percentage of BPA present as its conjugated species was > 90% in more than three-quarters of the premature infants. Intensity of use of products containing DEHP was strongly associated with BPA total concentrations but not with any other phenol. Adjusting for institution and sex, BPA total concentrations among infants in the group of high use of DEHP-containing products were 8.75 times as high as among infants in the low use group (p < 0.0001). Similarly, after adjusting for sex and DEHP-containing product use category, BPA total concentrations among infants in Institution A were 16.6 times as high as those among infants in Institution B (p < 0.0001). Conclusion: BPA geometric mean urinary concentration (30.3 μg/L) among premature infants undergoing intensive therapeutic medical interventions was one order of magnitude higher than that among the general population. Conjugated species were the primary urinary metabolites of BPA, suggesting that premature infants have some capacity to metabolize BPA. The differences in exposure to BPA by intensity of use of DEHP-containing medical products highlight the need for further studies to determine the specific source(s) of exposure to BPA
Characterisation of osteoprotegerin autoantibodies in coeliac disease
Objectives: Autoantibodies neutralising the effect of the bone regulatory cytokine osteoprotegerin (OPG) have been described in a patient with severe osteoporosis and coeliac disease. This study aimed to determine the prevalence and epitope specificity of autoantibodies to OPG in patients with coeliac disease, and correlate their presence with bone mineral density. Methods: A direct enzyme linked immunosorbent assay was developed and used to screen patients with coeliac disease for autoantibodies to OPG. Recombinant fragments of OPG were made to evaluate the epitope specificity and affinity of these antibodies. Phenotype information of the patients was obtained by case note review. Results: Raised titres of antibodies to OPG were found in 7/71 (9.8%) patients with coeliac disease, compared with 1/72 (1.4%) non-coeliac osteoporosis clinic control patients (p<0.05). Our results suggest a polyclonal antibody response to OPG is raised in these patients capable of recognising different epitopes of OPG with varying affinity. The titre of OPG antibodies was associated with lower bone mineral density Z score of the hip in coeliac patients on univariate (p<0.05) and multivariate analysis including age, sex height and weight as covariates (p<0.01). Conclusion: Polyclonal antibodies to OPG are more common in patients with coeliac disease and are independently associated with lower bone mineral density Z scores of the hip. Further work is required to establish the clinical utility of testing for OPG antibodies
Killing Tensors and Conformal Killing Tensors from Conformal Killing Vectors
Koutras has proposed some methods to construct reducible proper conformal
Killing tensors and Killing tensors (which are, in general, irreducible) when a
pair of orthogonal conformal Killing vectors exist in a given space. We give
the completely general result demonstrating that this severe restriction of
orthogonality is unnecessary. In addition we correct and extend some results
concerning Killing tensors constructed from a single conformal Killing vector.
A number of examples demonstrate how it is possible to construct a much larger
class of reducible proper conformal Killing tensors and Killing tensors than
permitted by the Koutras algorithms. In particular, by showing that all
conformal Killing tensors are reducible in conformally flat spaces, we have a
method of constructing all conformal Killing tensors (including all the Killing
tensors which will in general be irreducible) of conformally flat spaces using
their conformal Killing vectors.Comment: 18 pages References added. Comments and reference to 2-dim case.
Typos correcte
Anchored enrichment dataset for true flies (order Diptera) reveals insights into the phylogeny of flower flies (family Syrphidae)
Background: Anchored hybrid enrichment is a form of next-generation sequencing that uses oligonucleotide probes to target conserved regions of the genome flanked by less conserved regions in order to acquire data useful for phylogenetic inference from a broad range of taxa. Once a probe kit is developed, anchored hybrid enrichment is superior to traditional PCR-based Sanger sequencing in terms of both the amount of genomic data that can be recovered and effective cost. Due to their incredibly diverse nature, importance as pollinators, and historical instability with regard to subfamilial and tribal classification, Syrphidae (flower flies or hoverflies) are an ideal candidate for anchored hybrid enrichment-based phylogenetics, especially since recent molecular phylogenies of the syrphids using only a few markers have resulted in highly unresolved topologies. Over 6200 syrphids are currently known and uncovering their phylogeny will help us to understand how these species have diversified, providing insight into an array of ecological processes, from the development of adult mimicry, the origin of adult migration, to pollination patterns and the evolution of larval resource utilization. Results: We present the first use of anchored hybrid enrichment in insect phylogenetics on a dataset containing 30 flower fly species from across all four subfamilies and 11 tribes out of 15. To produce a phylogenetic hypothesis, 559 loci were sampled to produce a final dataset containing 217,702 sites. We recovered a well resolved topology with bootstrap support values that were almost universally >95 %. The subfamily Eristalinae is recovered as paraphyletic, with the strongest support for this hypothesis to date. The ant predators in the Microdontinae are sister to all other syrphids. Syrphinae and Pipizinae are monophyletic and sister to each other. Larval predation on soft-bodied hemipterans evolved only once in this family. Conclusions: Anchored hybrid enrichment was successful in producing a robustly supported phylogenetic hypothesis for the syrphids. Subfamilial reconstruction is concordant with recent phylogenetic hypotheses, but with much higher support values. With the newly designed probe kit this analysis could be rapidly expanded with further sampling, opening the door to more comprehensive analyses targeting problem areas in syrphid phylogenetics and ecology.Peer reviewe
Armut im Kontext reicher Staaten: zur wissenschaftlichen Operationalisierung eines normativen Begriffs
Eine der Schwierigkeiten bei der wissenschaftlichen Beschäftigung mit dem Themenbereich "Armut" ist der normative Gehalt dieses Konzepts. Das hat unter anderem damit zu tun, dass der Begriff nicht nur in wissenschaftlichen Analysen, sondern auch in der Alltagssprache verwendet und dabei zum Teil deutlich unterschiedlich definiert wird. Vor dem Hintergrund dieser Problematik hat es etliche Versuche gegeben, die wissenschaftliche Definition von Armut stärker an das Alltagsverständnis der Bevölkerung anzugleichen. Dabei zeigt sich, dass theoretisch-konzeptuelle Arbeiten zur exakten Formulierung des sozialen Phänomens "Armut" im Verlauf des letzten Jahrhunderts weit gediehen sind. Die empirische Umsetzbarkeit dieser Überlegungen stößt allerdings nach wie vor auf Grenzen, wie anhand von jüngeren Beispielen der Armutsberichterstattung für den EU- und OECD-Raum gezeigt wird.One of the difficulties in the scientific analysis of poverty is the normative content of this concept. This is not least based on the fact that the notion "poverty" is not only used for scientific purposes, but also by the population at large - with partly profound differences with regard to its interpretation. Against the background of this difficulty, several efforts have been made to adopt the scientific definition of poverty to more closely capture its public meaning. The conceptual-theoretical work to operationalise poverty has gone a long way within the last century. However, there are still quite some difficulties in translating the "new" concepts (which also lead to the establishment of alternative terminologies, e.g. "poverty risk" or "social exclusion") into practice, as is shown regarding recent examples of poverty reports for the region of the European Union and the OECD
The Ursinus Weekly, June 8, 1970
289 students graduate Ursinus today: Brooks Hays selected speaker at graduation • 1970 Honorary Degree recipients • Ursinus College class of 1970 • Focus: Bob Keehn • Departmental honorshttps://digitalcommons.ursinus.edu/weekly/1162/thumbnail.jp
The neutrino as a tachyon
We investigate the hypothesis that at least one of the known neutrinos travels faster than light. The current experimental situation is examined within this purview
Incidence and phenotypes of childhood-onset genetic epilepsies:a prospective population-based national cohort
Epilepsy is common in early childhood. In this age group it is associated with high rates of therapy-resistance, and with cognitive, motor, and behavioural comorbidity. A large number of genes, with wide ranging functions, are implicated in its aetiology, especially in those with therapy-resistant seizures. Identifying the more common single-gene epilepsies will aid in targeting resources, the prioritization of diagnostic testing and development of precision therapy. Previous studies of genetic testing in epilepsy have not been prospective and population-based. Therefore, the population-incidence of common genetic epilepsies remains unknown. The objective of this study was to describe the incidence and phenotypic spectrum of the most common single-gene epilepsies in young children, and to calculate what proportion are amenable to precision therapy. This was a prospective national epidemiological cohort study. All children presenting with epilepsy before 36 months of age were eligible. Children presenting with recurrent prolonged (>10 min) febrile seizures; febrile or afebrile status epilepticus (>30 min); or with clusters of two or more febrile or afebrile seizures within a 24-h period were also eligible. Participants were recruited from all 20 regional paediatric departments and four tertiary children’s hospitals in Scotland over a 3-year period. DNA samples were tested on a custom-designed 104-gene epilepsy panel. Detailed clinical information was systematically gathered at initial presentation and during follow-up. Clinical and genetic data were reviewed by a multidisciplinary team of clinicians and genetic scientists. The pathogenic significance of the genetic variants was assessed in accordance with the guidelines of UK Association of Clinical Genetic Science (ACGS). Of the 343 patients who met inclusion criteria, 333 completed genetic testing, and 80/333 (24%) had a diagnostic genetic finding. The overall estimated annual incidence of single-gene epilepsies in this well-defined population was 1 per 2120 live births (47.2/100 000; 95% confidence interval 36.9–57.5). PRRT2 was the most common single-gene epilepsy with an incidence of 1 per 9970 live births (10.0/100 000; 95% confidence interval 5.26–14.8) followed by SCN1A: 1 per 12 200 (8.26/100 000; 95% confidence interval 3.93–12.6); KCNQ2: 1 per 17 000 (5.89/100 000; 95% confidence interval 2.24–9.56) and SLC2A1: 1 per 24 300 (4.13/100 000; 95% confidence interval 1.07–7.19). Presentation before the age of 6 months, and presentation with afebrile focal seizures were significantly associated with genetic diagnosis. Single-gene disorders accounted for a quarter of the seizure disorders in this cohort. Genetic testing is recommended to identify children who may benefit from precision treatment and should be mainstream practice in early childhood onset epilepsy
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