Characterization of a small PlcR-regulated gene co-expressed with cereolysin O

<p>Abstract</p> <p>Background</p> <p>In the human pathogen <it>Bacillus cereus</it>, the expression of most extracellular virulence factors is controlled by the transcriptional activator PlcR. Among these virulence factors, cereolysin O (Clo) is an haemolysin belonging to the cholesterol-dependant cytolysins, a protein family extensively studied in Gram-positive bacteria.</p> <p>Results</p> <p>In the genomes of bacteria belonging to the <it>B. cereus </it>group, including <it>Bacillus anthracis </it>and <it>Bacillus thuringiensis</it>, a small gene encoding a 26-amino acid peptide was present in multicopy. One copy was always found upstream from the gene encoding Clo. In <it>B. cereus </it>ATCC 14579, the small gene and the <it>clo </it>gene are co-transcribed. Transcriptional fusions showed that the three paralogues identified in this strain were expressed in a PlcR-dependent manner. We propose to name these peptides Spp for small PlcR-regulated peptides. We show that a synthetic peptide corresponding to the deduced product of the <it>spp </it>genes displayed antibacterial activity.</p> <p>Conclusion</p> <p>The co-expression of <it>spp</it>, a small PlcR-regulated multicopy gene with <it>clo </it>suggests a yet unidentified relationship between Spp and the cholesterol-dependent cytolysin in bacteria belonging to the <it>B.cereus </it>group.</p

Relation between respiratory variations in pulse oximetry plethysmographic waveform amplitude and arterial pulse pressure in ventilated patients.

IntroductionRespiratory variation in arterial pulse pressure is a reliable predictor of fluid responsiveness in mechanically ventilated patients with circulatory failure. The main limitation of this method is that it requires an invasive arterial catheter. Both arterial and pulse oximetry plethysmographic waveforms depend on stroke volume. We conducted a prospective study to evaluate the relationship between respiratory variation in arterial pulse pressure and respiratory variation in pulse oximetry plethysmographic (POP) waveform amplitude.MethodThis prospective clinical investigation was conducted in 22 mechanically ventilated patients. Respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude were recorded simultaneously in a beat-to-beat evaluation, and were compared using a Spearman correlation test and a Bland-Altman analysis.ResultsThere was a strong correlation (r2 = 0.83; P &lt; 0.001) and a good agreement (bias = 0.8 +/- 3.5%) between respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude. A respiratory variation in POP waveform amplitude value above 15% allowed discrimination between patients with respiratory variation in arterial pulse pressure above 13% and those with variation of 13% or less (positive predictive value 100%).ConclusionRespiratory variation in arterial pulse pressure above 13% can be accurately predicted by a respiratory variation in POP waveform amplitude above 15%. This index has potential applications in patients who are not instrumented with an intra-arterial catheter

Flexible right sized honing technology for fast engine finishing

The paper discusses a flexible honing technology by describing the new prototype machine with its specificity. Three original methods produced by the flexible honing prototype have been studied. A path combines the two contemporary methods of industrial honing: the helical slide honing at 135 ° at the bottom of the cylinder and the conventional honing at 45 ° on the upper part. This method of honing shows the effectiveness of specific motion tracking to remove traces of inversions. Circular trajectories with large radii can be traveled quickly without consuming too much energy. The high cutting speed promotes the removal of material thus saving time. Finally, the multi-circle paths can get original textures thus proving the feasibility of all patterns

Un modèle de recul des falaises pour évaluer les fréquences d'éboulement

International audienceQuantitative assessment of diffuse rock fall hazard needs rock fall inventories, which are difficult to obtain for small or large rock fall volumes. In the case of localized hazard, a quantitative assessment is not possible in the present state of knowledge. A power law relation between rock fall frequency and volume is proposed for a better estimation of the frequencies. This relation has been used to build a rock wall retreat model, which can determine the age of the rock surface. The model has been applied to the calcareous cliffs of the Grenoble area. The calculated age is of the same order of magnitude than the mean age measured using the cosmogenic nuclides. The rock fall frequencies given by the power law relation can thus be used for a better estimation of diffuse and localized hazard, for the whole range of rock fall volumes

Eddies and interface deformations induced by optical streaming

We study flows and interface deformations produced by the scattering of a laser beam propagating through non-absorbing turbid fluids. Light scattering produces a force density resulting from the transfer of linear momentum from the laser to the scatterers. The flow induced in the direction of the beam propagation, called 'optical streaming', is also able to deform the interface separating the two liquid phases and to produce wide humps. The viscous flow taking place in these two liquid layers is solved analytically, in one of the two liquid layers with a stream function formulation, as well as numerically in both fluids using a boundary integral element method. Quantitative comparisons are shown between the numerical and analytical flow patterns. Moreover, we present predictive simulations regarding the effects of the geometry, of the scattering strength and of the viscosities, on both the flow pattern and the deformation of the interface. Finally, theoretical arguments are put forth to explain the robustness of the emergence of secondary flows in a two-layer fluid system

Smart Borders Revisited: An Assessment of the Commission’s Revised Smart Borders Proposal

This study, commissioned by the European Parliament's Policy Department for Citizens' Rights and Constitutional Affairs at the request of the LIBE Committee, appraises the revised legislative proposals (‘package’) on EU smart borders adopted by the European Commission on 6 April 2016. It provides a general assessment of the package, focusing in particular on costs, technical feasibility and overall proportionality, and a fundamental rights check of the initiative

Numerical modelling of released dredged sediment dispersion from Pandop harbour (New Caledonia)

Hydrodynamic

Numerical modelling of bacteriologic impacts in the Laïta estuary (France)

Hydrodynamic

Absence of antibodies to Rickettsia spp., Bartonella spp., Ehrlichia spp. and Coxiella burnetii in Tahiti, French Polynesia

International audienceAbtractBackgroundIn the Pacific islands countries and territories, very little is known about the incidence of infectious diseases due to zoonotic pathogens. To our knowledge, human infections due to Rickettsia spp., Coxiella burnetii, Ehrlichia spp. and Bartonella spp. have never been reported in French Polynesia; and infections due to C. burnetti have been reported worldwide except in New Zealand. To evaluate the prevalence of this disease, we conducted a serosurvey among French Polynesian blood donors.MethodsThe presence of immunoglobulin G antibodies against R. felis, R. typhi, R. conorii, C. burnetii, B. henselae, B. quintana, and E. chaffeensis was evaluated by indirect immunofluorescence assay in sera from 472 French Polynesian blood donors collected from 2011 to 2013. In addition, 178 ticks and 36 cat fleas collected in French Polynesia were also collected and tested by polymerase chain reaction to detect Rickettsia spp., B. henselae and Ehrlichia spp.ResultsNone of the blood donors had antibodies at a significant level against Rickettsia spp., Coxiella burnetii, Ehrlichia spp. and Bartonella spp. All tested ticks and cat fleas were PCR-negative for Rickettsia spp., B. henselae, and Ehrlichia spp.ConclusionWe cannot conclude that these pathogens are absent in French Polynesia but, if present, their prevalence is probably very low. C. burnetii has been reported worldwide except in New Zealand. It may also be absent from French Polynesia