RsaI, a multifaceted regulatory RNA, modulates the metabolism of the opportunistic pathogen Staphylococcus aureus RsaI, un ARN régulateur aux multiples facettes, module le métabolisme du pathogène opportuniste Staphylococcus aureus

Staphylococcus aureus est une bactérie commensale retrouvée chez environ 30 % des individus sains dont elle colonise la peau et la muqueuse nasale. Cependant, c’est également une bactérie pathogène opportuniste responsable d’infections diverses telles que orgelet, ostéomyélite, endocardite, ou encore septicémie en envahissant un grand nombre de tissus et d’organes. Cette bactérie est capable de s’adapter à des conditions hostiles et variées, telles que carence nutritive et stress osmotique, oxydant, ou thermique, ainsi qu’à la réponse immunitaire de l’hôte, car elle produit une grande diversité de facteurs de virulence. La synthèse de ces facteurs est finement régulée par des protéines et des ARN régulateurs majoritairement non codants, souvent désignés par l’abréviation sARN (dérivée de l’anglais, small RNA). Les facteurs de transcription et les systèmes à deux composants contrôlent l’expression des gènes impliqués non seulement dans le métabolisme, mais aussi dans la réponse au stress et la virulence [1]. Par exemple, la protéine du contrôle catabolique (carbon catabolite control protein A, CcpA) a un rôle essentiel dans le choix de la source carbonée en régulant le métabolisme central de la bactérie ainsi que la virulence [2, 3]. CcpA se fixe à une séquence promotrice spécifique appelée cre (catabolite-responsive element), qui est très conservée chez les bactéries à Gram positif [2]. Quant aux sARN, ils interagissent principalement avec leurs ARN messagers (ARNm) cibles. L’hybridation peut conduire à la stabilisation/déstabilisation de l’ARNm ou à l’activation/répression de sa traduction [4]. Nous avons montré que la transcription du sARN RsaI (RNA Staphylococcus aureus I) est réprimée par CcpA en présence de glucose [5]. L’induction de la synthèse de RsaI signale que la concentration en glucose diminue dans le milieu extracellulaire et que la croissance des bactéries est ralentie. En interagissant avec ses ARNm cibles ou d’autres sARN, il permet à la population bactérienne de modifier son métabolisme lorsque la source carbonée primaire est consommée

Case report : De novo pathogenic variant in WFS1 causes Wolfram-like syndrome debuting with congenital bilateral deafness

Background: Congenital deafness could be the first manifestation of a syndrome such as in Usher, Pendred, and Wolfram syndromes. Therefore, a genetic study is crucial in this deficiency to significantly improve its diagnostic efficiency, to predict the prognosis, to select the most adequate treatment required, and to anticipate the development of other associated clinical manifestations. Case presentation: We describe a young girl with bilateral congenital profound deafness, who initially received a single cochlear implant. The genetic study of her DNA using a custom-designed next-generation sequencing (NGS) panel detected a de novo pathogenic heterozygous variant in the WFS1 gene related to Wolfram-like syndrome, which is characterized by the presence of other symptoms such as optic atrophy. Due to this diagnosis, a second implant was placed after the optic atrophy onset. The speech audiometric results obtained with both implants indicate that this work successfully allows the patient to develop normal speech. Deterioration of the auditory nerves has not been observed. Conclusion: The next-generation sequencing technique allows a precise molecular diagnosis of diseases with high genetic heterogeneity, such as hereditary deafness, while this was the only symptom presented by the patient at the time of analysis. The NGS panel, in which genes responsible for both syndromic and non-syndromic hereditary deafness were included, was essential to reach the diagnosis in such a young patient. Early detection of the pathogenic variant in the WFS1 gene allowed us to anticipate the natural evolution of the disease and offer the most appropriate management to the patient

Synthesis, characterization, and permeability evaluation of hybrid organic-inorganic films

The preparation and characterization of hybrid organic-inorganic films based on poly(dimethylsiloxane), PDMS, crosslinked with nanoclusters obtained from pentaerythrithol triacrylate (PETA) and 2-aminoethyl-3-aminopropyltrimethoxysilane (AS), are reported. The introduction of silica nanoclusters, obtained from tetraethoxysilane as an additional crosslinker, improved the mechanical stability of the films and also produced a noticeable decrease in the solvent sorption and in the distance between the nodes of the polymeric networks. The performance of these films as membranes for gas separation processes was similar to those reported for commercial PDMS, although they presented polar organic PETA/AS crosslinker nuclei. (C) 2004 Wiley Periodicals, Inc.42234281429

Poly(n-alkylsilsesquioxane)s: Synthesis, Characterization, and Modification with Poly(dimethylsiloxane)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Self-supported translucent films constituted of poly(n-octylsilsesquioxane) or poly(n-dodecylsilsesquioxane) were obtained from the hydrolysis and condensation of n-octyltriethoxysilane (OTES) or n-dodecyltriethoxysi lane (DTES), respectively. Dense films were obtained in the absence of organic solvents, with dibutyltin diacetate as catalyst. These films exhibited good optical transparency and thermal stability. The incorporation of oligomeric dimethylsiloxane units (D(Me,Me)) in these materials, derived from silanol-terminated poly(dimethylsiloxane) (PDMS) or 1,1,3,3-tetramethyl-1,3-diethoxydisiloxane (TMDES), was carried out during the hydrolysis and condensation of OTES and DTES and was confirmed by solid-state (29)Si NMR. Poly(n-octylsilsesquioxane) showed a glass-transition temperature at -65 degrees C, due to the increase in the free volume, promoted by the bulky n-octyl groups. The differential scanning calorimetric (DSC) curves of the polymer derived from DTES were characterized by first-order transitions at temperatures ranging from -15.8 to -0.7 degrees C. Further studies of these networks by low-temperature XRD evidenced narrowing of the diffraction halos suggesting a partial order-disorder transition for these materials at lower temperatures. Good thermal stability up to 350 degrees C and the solvent-free production process make these polymers potential candidates for the development of self-supported hydrophobic protective coatings. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1220-1229, 201048512201229Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [03/09, 962-1]CNPq [305916/2006-8

Poly(dimethylsiloxane) networks modified with poly (phenylsilsesquioxane)s: Synthesis, structural characterisation and evaluation of the thermal stability and gas permeability

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Self-supported translucent films constituted of semi-inorganic polymeric materials were prepared by sol-gel process from poly(phenylsilsesquioxane) (PPSQ) and poly(dimethylsiloxane) (PDMS), modified by diphenylsilanediol (DPS), phenyltriethoxysilane (PTES) and/or tetraethoxysilane (TEOS). These materials were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA). Permeability to N-2, O-2, CH4 and CO2 and selectivity for a specific gas pair were investigated using the time-lag method. In the gas separation process high permeability and selectivity coefficients were observed, particularly for the membrane containing DPS and PTES as additives, which presented potential applications in the separation of CO2/CH4 and CO2/N-2. The materials also showed good thermal stability, which could be correlated to the relative amounts between di-functional (D), tri-functional (T) and tetra-functional (Q) silicon units. (c) 2008 Elsevier Ltd. All rights reserved.441030803086Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [03/09962-1]CNPq [305916/2006-8

RsaI, un ARN régulateur aux multiples facettes, module le métabolisme du pathogène opportuniste <i>Staphylococcus aureus</i>

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The auxin-resistant dgt tomato mutant grows less than the wild type but is less sensitive to ammonium toxicity and nitrogen deficiency

The low-auxin-sensitivity tomato mutant, dgt, despite displaying reduced plant growth, has been linked to greater resistance to N deficiency. This led us to test the role of auxin resistance of dgt in NH toxicity and N deficiency, compared to wild type tomato (cv. Micro-Tom, MT), grown in hydroponic media. A completely randomized design with three replications in a 2 × 4 factorial scheme was adopted, corresponding to the two tomato genotypes (MT and dgt), involving four nutritional treatments: NO (5 mM); NH (5 mM); NO (5 mM) plus exogenous auxin (10 μM IAA); and N omission. The results show that NH was toxic to MT but not to dgt. Under N deficiency, MT displayed a lower shoot NO content, a lower photosynthetic rate, and a decrease in both shoot and root dry weight. However, in dgt, no difference was observed in shoot NO content and photosynthetic rate between plants grown on NO or under N deficiency. In addition, dgt showed an increase in shoot dry weight under N deficiency. We highlight the role of auxin resistance in the adaptation of plants to NH toxicity and N deficiency