Expression of the translocator protein (TSPO) from Pseudomonas fluorescens Pf0-1 requires the stress regulatory sigma factors AlgU and RpoH

International audienceThe translocator protein (TSPO), previously designated as peripheral-type benzodiazepine receptor, is an evolutionary conserved protein that is found in many Eukarya, Archae and Bacteria, in which it plays several important functions including membrane biogenesis, signaling and stress response. A tspo homologue gene has been identified in several members of the Pseudomonas genus, among which the soil bacterium P. fluorescens Pf0-1. In this bacterium, the tspo gene is located in the vicinity of a putative hybrid histidine kinase-encoding gene. Since tspo has been involved in water stress related response in plants, we explored the effects of hyperosmolarity and temperature on P. fluorescens Pf0-1 tspo expression using a strategy based on lux-reporter fusions. (B) Co-transcription of Pfl01_2810 and tspo by RT-PCR assay. RT-PCR was assayed on tspo (1), Pfl01_2810 (2) and on the putative operonic structure Pfl01_2810-tspo (3), using primers located into tspo (1) or Pfl01_2810 (2) ORFs, or into both tspo and Pfl01_2810 ORFs (3). RT-PCR achieved on total RNA did not lead to a PCR fragment (line 4, negative control). L: Ladder 1kb+ (Biorad ®), (C) Growth curves in microtitre wells in LB medium at 28 C and relative luminescence (RL) activity of pTSPO and pHK-TSPO in P. fluorescens Pf0-1. The tspo gene (Pfl01_2811) of P. fluorescens Pf0-1 forms an operonic structure with Pfl01_2810 and is expressed transiently during the bacterial growth. (A) Schematic representation of the genomic environment of tspo and of transcriptional fusions pTSPO and pHK-TSPO. Grey bars represent the beginning of the luxCDABE reporter cassette of the promoterless pAB133 vector. The position of the studied promoter region is indicated relatively to the translational initiation start of each ORF. Pfl01_ 2809 lux CDABE pHK-TSPO-253 bp lux CDABE pTSPO-227 bp P. fluorescens Pf0-1 chromosome lux transcriptional fusions Pfl01_2810 tsp

Lipoproteins of Enterococcus faecalis: bioinformatic identification, expression analysis and relation to virulence.

International audienceEnterococcus faecalis is a ubiquitous bacterium that is capable of surviving in a broad range of natural environments, including the human host, as either a natural commensal or an opportunistic pathogen involved in severe hospital-acquired infections. How such opportunistic pathogens cause fatal infections is largely unknown but it is likely that they are equipped with sophisticated systems to perceive external signals and interact with eukaryotic cells. Accordingly, being partially exposed at the cell exterior, some surface-associated proteins are involved in several steps of the infection process. Among them are lipoproteins, representing about 25 % of the surface-associated proteins, which could play a major role in bacterial virulence processes. This review focuses on the identification of 90 lipoprotein-encoding genes in the genome of the E. faecalis V583 clinical strain and their putative roles, and provides a transcriptional comparison of microarray data performed in environmental conditions including blood and urine. Taken together, these data suggest a potential involvement of lipoproteins in E. faecalis virulence, making them serious candidates for vaccine production

La drosophile et l’homme partagent des mécanismes similaires de régulation de la sécrétion d’insuline

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Structure-to-function relationships of bacterial translocator protein (TSPO): a focus on Pseudomonas

International audienceThe translocator protein (TSPO), which was previously designated as the peripheral-type benzodiazepine receptor, is a 3.5 billion year-old evolutionarily conserved protein expressed by most Eukarya, Archae and Bacteria, but its organization and functions differ remarkably. By taking advantage of the genomic data available on TSPO, we focused on bacterial TSPO and attempted to define functions of TSPO in Pseudomonas via in silico approaches. A tspo ortholog has been identified in several fluorescent Pseudomonas. This protein presents putative binding motifs for cholesterol and PK 11195, which is a specific drug ligand of mitochondrial TSPO. While it is a common surface distribution, the sense of insertion and membrane localization differ between α- and γ-proteobacteria. Experimental published data and STRING analysis of common TSPO partners in fluorescent Pseudomonas indicate a potential role of TSPO in the oxidative stress response, iron homeostasis and virulence expression. In these bacteria, TSPO could also take part in signal transduction and in the preservation of membrane integrity

Mesoporous Bioactive Glasses Cytocompatibility Assessment: A Review of In Vitro Studies

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Comparison of the Biological Behavior and Topographical Surface Assessment of a Minimally Invasive Dental Implant and a Standard Implant: An In Vitro Study

The current study aimed to assess the topographical and physical properties of a minimally invasive implant (MagiCore®: MC®, InnosBioSurg, IBS) and to evaluate its biological behavior compared to a gold standard implant (NobelParallel™: NB™, Nobel Biocare™). After surface characterization, the biological behavior assessment was conducted regarding human gingival fibroblasts (hGF) and osteoblast-like cells (MG63). Roughness values for NBTM were Ra = 1.28 µm and for MC® they were Ra = 2.02 µm. Alamar BlueTM assay LIVE/DEADTM staining results indicated equivalent biological development regarding both cell types for the two implants. Significant enhancement was found for hGF ALP activity in the presence of the two tested implants in a time-dependent manner from day 7 to day 14 (** p ® implant (** p ® than the NB™ surface. The MC® cytocompatibility was ranked as equivalent to the gold standard implant despite the surface properties differences. These findings provide new insights about the minimally invasive implant’s biological behavior and its potential clinical implication in different implantology situations

Cytotoxicity and inflammatory potential of two Pseudomonas mosselii strains isolated from clinical samples of hospitalized patients

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The parameters influencing the morphology of poly(?-caprolactone) microspheres and the resulting release of encapsulated drugs

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3D Electrospun Polycaprolactone Scaffolds to Assess Human Periodontal Ligament Cells Mechanobiological Behaviour

While periodontal ligament cells are sensitive to their 3D biomechanical environment, only a few 3D in vitro models have been used to investigate the periodontal cells mechanobiological behavior. The objective of the current study was to assess the capability of a 3D fibrous scaffold to transmit a mechanical loading to the periodontal ligament cells. Three-dimensional fibrous polycaprolactone (PCL) scaffolds were synthetized through electrospinning. Scaffolds seeded with human periodontal cells (10 3 mL −1) were subjected to static (n = 9) or to a sinusoidal axial compressive loading in an in-house bioreactor (n = 9). At the end of the culture, the dynamic loading seemed to have an influence on the cells' morphology, with a lower number of visible cells on the scaffolds surface and a lower expression of actin filament. Furthermore, the dynamic loading presented a tendency to decrease the Alkaline Phosphatase activity and the production of Interleukin-6 while these two biomolecular markers were increased after 21 days of static culture. Together, these results showed that load transmission is occurring in the 3D electrospun PCL fibrous scaffolds, suggesting that it can be used to better understand the periodontal ligament cells mechanobiology. The current study shows a relevant way to investigate periodontal mechanobiology using 3D fibrous scaffolds

Expression of the translocator protein (TSPO) from Pseudomonas fluorescens Pf0-1 requires the stress regulatory sigma factors AlgU and RpoH

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