Membrane fluidity homeostasis is required for tobramycin-enhanced biofilm in .

is an opportunistic pathogen, which causes chronic infections, especially in cystic fibrosis (CF) patients where it colonizes the lungs via the build-up of biofilms. Tobramycin, an aminoglycoside, is often used to treat infections in CF patients. Tobramycin at sub-minimal inhibitory concentrations enhances both biofilm biomass and thickness ; however, the mechanism(s) involved are still unknown.

Practical identifiability in the frame of nonlinear mixed effects models: the example of the in vitro erythropoiesis.

Background: Nonlinear mixed effects models provide a way to mathematically describe experimental data involving a lot of inter-individual heterogeneity. In order to assess their practical identifiability and estimate confidence intervals for their parameters, most mixed effects modelling programs use the Fisher Information Matrix. However, in complex nonlinear models, this approach can mask practical unidentifiabilities.

The Temperature-Regulation of Operon Reveals an Intriguing Molecular Network Involving the Sigma Factors AlgU and SigX.

is a highly adaptable Gram-negative opportunistic pathogen, notably due to its large number of transcription regulators. The extracytoplasmic sigma factor (ECFσ) AlgU, responsible for alginate biosynthesis, is also involved in responses to cell wall stress and heat shock via the RpoH alternative σ factor. The SigX ECFσ emerged as a major regulator involved in the envelope stress response via membrane remodeling, virulence and biofilm formation.

Drugs modulating stochastic gene expression affect the erythroid differentiation process.

To better understand the mechanisms behind cells decision-making to differentiate, we assessed the influence of stochastic gene expression (SGE) modulation on the erythroid differentiation process. It has been suggested that stochastic gene expression has a role in cell fate decision-making which is revealed by single-cell analyses but studies dedicated to demonstrate the consistency of this link are still lacking. Recent observations showed that SGE significantly increased during differentiation and a few showed that an increase of the level of SGE is accompanied by an increase in the differentiation process.

Extracellular DNA release, quorum sensing, and PrrF1/F2 small RNAs are key players in tobramycin-enhanced biofilm formation.

Biofilms are structured microbial communities that are the leading cause of numerous chronic infections which are difficult to eradicate. Within the lungs of individuals with cystic fibrosis (CF), causes persistent biofilm infection that is commonly treated with aminoglycoside antibiotics such as tobramycin. However, sublethal concentrations of this aminoglycoside were previously shown to increase biofilm formation by , but the underlying adaptive mechanisms still remain elusive.

Calibration, Selection and Identifiability Analysis of a Mathematical Model of the in vitro Erythropoiesis in Normal and Perturbed Contexts.

The in vivo erythropoiesis, which is the generation of mature red blood cells in the bone marrow of whole organisms, has been described by a variety of mathematical models in the past decades. However, the in vitro erythropoiesis, which produces red blood cells in cultures, has received much less attention from the modelling community. In this paper, we propose the first mathematical model of in vitro erythropoiesis.

In vitro antimicrobial susceptibility of equine clinical isolates from France, 2006-2016.

Objectives: This study aimed to analyse antimicrobial susceptibility evolution of equine pathogens isolated from clinical samples from 2006-2016.

Methods: A collection of 25 813 bacterial isolates was studied, clustered according to their origins (respiratory tract, cutaneous, genital and other), and analysed for their antimicrobial susceptibility using the disk diffusion method.

Results: The most frequently isolated pathogens were group C Streptococci (27.

The absence of SigX results in impaired carbon metabolism and membrane fluidity in Pseudomonas aeruginosa.

In Pseudomonas aeruginosa, SigX is an extra-cytoplasmic function σ factor that belongs to the cell wall stress response network. In previous studies, we made the puzzling observation that sigX mutant growth was severely affected in rich lysogeny broth (LB) but not in minimal medium. Here, through comparative transcriptomic and proteomic analysis, we show that the absence of SigX results in dysregulation of genes, whose products are mainly involved in transport, carbon and energy metabolisms.

Extracytoplasmic function sigma factors in Pseudomonas aeruginosa.

The opportunistic pathogen Pseudomonas aeruginosa, like all members of the genus Pseudomonas, has the capacity to thrive in very different environments, ranging from water, plant roots, to animals, including humans to whom it can cause severe infections. This remarkable adaptability is reflected in the number of transcriptional regulators, including sigma factors in this bacterium. Among those, the 19 to 21 extracytoplasmic sigma factors (ECFσ) are endowed with different regulons and functions, including the iron starvation σ (PvdS, FpvI, HasI, FecI, FecI2 and others), the cell wall stress ECFσ AlgU, SigX and SbrI, and the unorthodox σ involved in the expression of virulence.

The absence of the Pseudomonas aeruginosa OprF protein leads to increased biofilm formation through variation in c-di-GMP level.

OprF is the major outer membrane porin in bacteria belonging to the Pseudomonas genus. In previous studies, we have shown that OprF is required for full virulence expression of the opportunistic pathogen Pseudomonas aeruginosa. Here, we describe molecular insights on the nature of this relationship and report that the absence of OprF leads to increased biofilm formation and production of the Pel exopolysaccharide.

Sucrose favors Pseudomonas aeruginosa pellicle production through the extracytoplasmic function sigma factor SigX.

Pseudomonas aeruginosa biofilm formation was increased by addition of sucrose to Luria-Bertani medium, whereas addition of NaCl to a final similar osmolarity and use of maltose instead of sucrose, were ineffective. In a previous study, we showed that the extracytoplasmic sigma factor SigX is activated in the presence of sucrose. The sucrose-mediated pellicle increase was abolished in a sigX mutant strain.

A proteomic approach of SigX function in Pseudomonas aeruginosa outer membrane composition.

Unlabelled: SigX is one of the 19 extracytoplasmic function sigma factors that have been predicted in the human opportunistic pathogen Pseudomonas aeruginosa genome. SigX is involved in the transcription of oprF, encoding the major outer membrane protein OprF, a pleiotropic porin that contributes to the maintaining of the wall structure, and is essential to P. aeruginosa virulence.

UT-A urea transporter protein in heart: increased abundance during uremia, hypertension, and heart failure.

Urea transporters have been cloned from kidney medulla (UT-A) and erythrocytes (UT-B). We determined whether UT-A proteins could be detected in heart and whether their abundance was altered by uremia or hypertension or in human heart failure. In normal rat heart, bands were detected at 56, 51, and 39 kDa.

Intraocular pressure change measured by Goldmann tonometry after laser in situ keratomileusis.

Purpose: To assess the accuracy of Goldmann tonometry after laser in situ keratomileusis (LASIK).

Setting: University-based refractive surgery group (Clinique du Laser Visuel).

Method: The database of patients who had LASIK was retrospectively reviewed.

[Polyethylene wear of the Optifix cementless acetabular component after 5 years].

The aim of this study is to review our experience with the Optifix porous-coated cementless acetabular component at an average 5 year follow-up. In a retrospective clinical investigation, the amount and rate of linear wear of the polyethylene of 26 cementless Optifix acetabular components implanted during a primary Hybrid (Spectron femoral component) total hip replacement in 24 patients, were determined by a comparison of the thicknesses of the cup as measured on the initial and most recent follow-up radiographs. The measurements were corrected for magnification error by direct measurement of the diameter of the femoral head on each radiograph according to the technique of Livermore et al.

[Non-cemented self-locking total arthroplasty of the hip. Clinical and radiological results after three years].

We reviewed 47 patients who had fifty-one (51) primary, cementless biofit total hip arthroplasties (THA) implanted at Maisonneuve-Rosemont Hospital between 1986 and 1990. An independent observer rated the patients on the Harris Hip Score (HHS) by questionnaire, physical examination and radiological assessment. The average follow-up was 40 months.

Hip fractures and Parkinson's disease. A clinical review of 94 fractures treated surgically.

A series of 87 parkinsonian patients with 94 hip fractures were reviewed to reexamine the evidence for internal fixation versus hemiarthroplasty. Forty-seven subcapital Garden Type I and Type II fractures and transcervical fractures were treated by nailing, and 47 Garden Type III and Type IV fractures were treated by hemiarthroplasty. There were twice as many complications in the hemiarthroplasty group as in patients treated by nailing, including four wound infections and five dislocations, all with uniformly bad results.

[Analysis of non-optimal behavior in a dichotomous choice situation].

Proteau and Girouard (1987) have recently proposed a model to explain the decisional process that takes place in a two-choice reaction time situation. Although the model was well supported by the experimental data reported by these authors, a few unexplained results were observed and hypotheses were suggested to account for them. The goal of the present experiment was, first, to replicate the results presented by Proteau and Girouard (1987) to support their model.

Bone imaging after cementless press fit total hip arthroplasty.

In view of the high rate of loosening of conventional cemented hip prostheses, cementless implants are gaining popularity in Europe and North America. Smooth-surfaced "press fit" prostheses are designed for autolocking in the femoral canal at the time of installation. Fifteen patients were prospectively followed by bone imaging with Tc-99m MDP at three-month intervals after cementless "press fit" hip arthroplasty to define the "normal" distribution of mechanical stress to the surrounding bone, as well as the incorporation of bone allografts used for reconstruction of resorption sites in cases of revision surgery.

Full oestrogenic activity of C19-delta 5 adrenal steroids in rat pituitary lactotrophs and somatotrophs.

Oestrogens are known to exert specific stimulatory effects on basal and dopamine (DA)-inhibited prolactin (PRL) release as well as on PRL cell content in rat adenohypophysial cells in primary culture. Recently, we have demonstrated that classical oestrogens increase growth hormone (GH) release and cellular GH content in rat pituitary somatotrophs. Since there is evidence that 5-androstene-3 beta, 17 beta-diol (delta 5-diol), a metabolite of dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEA-S) can induce typical oestrogenic responses in target tissues, we have investigated the effect of C19 adrenal steroids and compared them to that of 17 beta-oestradiol (E2) on the above-indicated parameters.

Pharmacological effects of meptazinol and its enantiomers on guinea-pig ileum and mouse vas deferens.

Electrically induced twitch responses of mouse vas deferens and guinea-pig ileum were inhibited by morphine, normorphine and the peptide opioid agonist RX783006; naloxone blocked the effects of all three opioid agonists yielding Ke values which were not significantly different and which were within the range (1-4 nM) expected for mu-type receptors. At concentrations between 0.1 and 10 microM (+)-meptazinol inhibited the twitch response of the ileum while (-)-meptazinol produced potentiation.