107 research outputs found
Characterizing the pathotype of neonatal meningitis causing <i>Escherichia coli</i> (NMEC)
Background
Neonatal meningitis-causing Escherichia coli (NMEC) is the predominant Gram-negative bacterial pathogen associated with meningitis in newborn infants. High levels of heterogeneity and diversity have been observed in the repertoire of virulence traits and other characteristics among strains of NMEC making it difficult to define the NMEC pathotype. The objective of the present study was to identify genotypic and phenotypic characteristics of NMEC that can be used to distinguish them from commensal E. coli.
Methods
A total of 53 isolates of NMEC obtained from neonates with meningitis and 48 isolates of fecal E. coli obtained from healthy individuals (HFEC) were comparatively evaluated using five phenotypic (serotyping, serum bactericidal assay, biofilm assay, antimicorbial susceptibility testing, and in vitro cell invasion assay) and three genotypic (phylogrouping, virulence genotyping, and pulsed-field gel electrophoresis) methods.
Results
A majority (67.92 %) of NMEC belonged to B2 phylogenetic group whereas 59 % of HFEC belonged to groups A and D. Serotyping revealed that the most common O and H types present in NMEC tested were O1 (15 %), O8 (11.3 %), O18 (13.2 %), and H7 (25.3 %). In contrast, none of the HFEC tested belonged to O1 or O18 serogroups. The most common serogroup identified in HFEC was O8 (6.25 %). The virulence genotyping reflected that more than 70 % of NMEC carried kpsII, K1, neuC, iucC, sitA, and vat genes with only less than 27 % of HFEC possessing these genes. All NMEC and 79 % of HFEC tested were able to invade human cerebral microvascular endothelial cells. No statistically significant difference was observed in the serum resistance phenotype between NMEC and HFEC. The NMEC strains demonstrated a greater ability to form biofilms in Luria Bertani broth medium than did HFEC (79.2 % vs 39.9 %).
Conclusion
The results of our study demonstrated that virulence genotyping and phylogrouping may assist in defining the potential NMEC pathotype
Evolution of Gaussian wave packets in capillary jets
A temporal analysis of the evolution of Gaussian wave packets in cylindrical capillary jets is
presented through both a linear two-mode formulation and a one-dimensional nonlinear numerical
scheme. These analyses are normally applicable to arbitrary initial conditions but our study focuses
on pure-impulsive ones. Linear and nonlinear findings give consistent results in the stages for which
the linear theory is valid. The inverse Fourier transforms representing the formal linear solution
for the jet shape is both numerically evaluated and approximated by closed formulas. After a
transient, these formulas predict an almost Gaussian-shape deformation with (i) a progressive drift
of the carrier wave number to that given by the maximum of the Rayleigh dispersion relation, (ii)
a progressive increase of its bell width, and (iii) a quasi-exponential growth of its amplitude. These
parameters agree with those extracted from the fittings of Gaussian wave packets to the numerical
simulations. Experimental results are also reported on near-Gaussian pulses perturbing the exit
velocity of a 2 mm diameter water jet. The possibility of controlling the breakup location along the
jet and other features, such as pinch-off simultaneity, are demonstrated
Stressed out symbiotes:hypotheses for the influence of abiotic stress on arbuscular mycorrhizal fungi
Abiotic stress is a widespread threat to both plant and soil communities. Arbuscular mycorrhizal (AM) fungi can alleviate effects of abiotic stress by improving host plant stress tolerance, but the direct effects of abiotic stress on AM fungi are less well understood. We propose two hypotheses predicting how AM fungi will respond to abiotic stress. The stress exclusion hypothesis predicts that AM fungal abundance and diversity will decrease with persistent abiotic stress. The mycorrhizal stress adaptation hypothesis predicts that AM fungi will evolve in response to abiotic stress to maintain their fitness. We conclude that abiotic stress can have effects on AM fungi independent of the effects on the host plant. AM fungal communities will change in composition in response to abiotic stress, which may mean the loss of important individual species. This could alter feedbacks to the plant community and beyond. AM fungi will adapt to abiotic stress independent of their host plant. The adaptation of AM fungi to abiotic stress should allow the maintenance of the plant-AM fungal mutualism in the face of changing climates. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00442-016-3673-7) contains supplementary material, which is available to authorized users
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
Gardens of happiness: Sir William Temple, temperance and China
This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordSir William Temple, an English statesman and humanist, wrote “Upon the
Gardens of Epicurus” in 1685, taking a neo-epicurean approach to happiness
and temperance. In accord with Pierre Gassendi’s epicureanism, “happiness” is
characterised as freedom from disturbance and pain in mind and body, whereas
“temperance” means following nature (Providence and one’s physiopsychological constitution). For Temple, cultivating fruit trees in his garden was
analogous to the threefold cultivation of temperance as a virtue in the humoral
body (as food), the mind (as freedom from the passions), and the bodyeconomic (as circulating goods) in order to attain happiness. A regimen that was
supposed to cure the malaise of Restoration amidst a crisis of unbridled
passions, this threefold cultivation of temperance underlines Temple’s reception
of China and Confucianism wherein happiness and temperance are highlighted.
Thus Temple’s “gardens of happiness” represent not only a reinterpretation of
classical ideas, but also his dialogue with China.European CommissionLeverhulme Trus
Hesperitin Esters : Highly Stable Flavanones With Both Free Radical Scavenging and Anti-Elastase Activities.
A one-step synthesis of 2-alkyl-5-hydroxychromones and 3-alkoyl-2-alkyl-5-hydroxychromones
International audienc
Discovery of Benzylidenebenzofuran-3(2H)-one (Aurones) as Potent Inhibitors of Human Tyrosinase
International audienc
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