STER1, a novel receptor-like kinase, functions in MAMP signalling in Arabidopsis

S. epidermidis has long been recognized as an important opportunistic pathogen accounting for the majority of nosocomial infections alongside S. aureus. However, in spite of this, our understanding of the S. epidermidis virulence mechanisms is still limited. Previous studies have emphasized various analogies in innate immunity against pathogens in plant, invertebrate and mammalian hosts. When compared to in vivo animal models, plant models are an attractive alternative and experiments using the S.aureus-Arabidopsis pathosystem have shown potential for this approach with S. epidermidis. In this study, an Arabidopsis−S.epidermidis system was established aiming to identify possible bacterial virulence traits. As S. epidermidis is not a true plant pathogen it fails to multiply in planta; however, most S. epidermidis strains tested generated a salycilic acid (SA)-dependent necrotic phenotype in Arabidopsis 5 days−post inoculation. Additionally, inoculation with boiled bacteria generated the same visual response as live cells, suggesting a pre−existent, heat stable molecule underlies the plant visual response. Taken together, this data suggests the necrotic response is a visual expression of MAMP perception. Subsequent exploitation of the Arabidopsis natural variation through QTL analysis, resulted in the isolation of the STER1 (Staphylococcus elicitor response 1) gene. This gene is essential for the visual response to S. epidermidis 18888 and encodes a membrane localized DUF26−containing receptor−like kinase. The ster1-1 mutant remained asymptomatic following inoculation with Gram−positive S. epidermidis 18888 and Gram−negative B. ambifaria, suggesting STER1’s likely role in the recognition of a common molecule. Peptidoglycan (PGN), an essential bacterial membrane component was considered a likely candidate and isolated from both species. Inoculation with B. ambifaria PGN generates a plant response that mirrores the one seen with bacterial suspensions of the same organism. By contrast, pure S. epidermidis 18888 PGN does not trigger a visual response in Arabidopsis. Instead, an S. epidermidis 18888 membrane fraction (MF), consisting of PGN, teichoic acid (TA) and an uncharacterized capsular polysaccharide (CPS), was found to generate a necrotic response similar to live cells. Treatment with S. epidermidis MF and B. ambifaria PGN triggered stereotypical defence responses, such as PR1 up−regulation and cell death in wild−type plants, but not in the ster1-1 mutant. Additionally, pre-treatment with S. epidermidis MF and B. ambifaria PGN also restricted Pst DC3000 growth in wild−type plants only, thus emphasizing a likely role for STER1 in basal resistance and PGN perception. In conclusion, the data obtained in this study implicate STER1 in PGN and possibly specialized CPS recognition, either as a receptor, co-receptor or essential signalling component

BIOCHEMICAL AND HISTOLOGICAL EFFECTS OF DELTAMETHRIN EXPOSURE ON THE GILLS OF CARASSIUS AURATUS GIBELIO (Pisces Cyprinidae)

This study investigated the alterations in the activities of several antioxidant enzymesin the gills of the freshwater fish Carassius auratus gibelio exposed to deltamethrin.To get this goal, groups of 10 individuals were exposed for one, two, three, sevenand fourteen days to sublethal concentration of deltamethrin (2 g/L). Anothergroup was used as control. The activities of catalase, gluthatione peroxidase andgluthatione reductase were significantly decreased, while the glutathione-Stransferasewas up-regulated. All fish, exposed to 2glL deltamethrin revealed gillsmorphological alterations after 48h of exposure which were accentuated after 14days. In the gills hyperemia, fusion of secondary lamellae, epithelial layer ruptureand chloride cells proliferation were observed. These results suggest that animmediate adaptive response to the oxidative stress appeared, demonstratingalterations in the antoxidant defense mechanism in the gills of deltamethrinintoxicated fish

Systematic investigation and in vitro biocompatibility studies on mesoporous europium doped hydroxyapatite

International audienceThis paper reports a systematic investigation on europium doped hydroxyapatite (Eu:HAp). In this work, a set of complementary techniques Fourier Transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and, Brunauer-Emmett-Teller (BET) technique was used to allowing a proper understanding of Eu:HAp. The XPS analysis confirmed the substitution of Ca ions by Eu ions in Eu:HAp samples. Eu:HAp and pure HAp show the isotherms of type IV with a hysteresis loop at a relative pressure (P/P0) between 0.4 and 1.0, indicating the presence of mesopores. Finally, the in vitro biological effects of Eu:HAp nanoparticles were evaluated by focusing on F-actin filaments pattern and heat shock proteins (Hsp) expression in HEK293 human kidney cells. Fluorescence microscopy studies of the actin protein revealed no changes of the immunolabeling profile in the renal cells cultured in the presence of Eu:HAp nanoparticles. Hsp60, Hsp70 and Hsp90 expression measured by Western blot analysis were not affected after a 24 and 48 hours exposure. These results confirmed the lack of nanoparticles' toxicity and the biocompatibility of Eu:HAp nanoparticles and their possibility possible uses of using them in medical purposes without affecting the renal function

Water Soluble Pleurotus ostreatus Polysaccharide Down-Regulates the Expression of MMP-2 and MMP-9 in Caco-2 Cells

Many polysaccharides and polysaccharide-protein complexes isolated from mushrooms have immunomodulatory and anti-cancer effects. Our aim was to study the regulatory mechanisms of Caco-2 cell response to water soluble P. ostreatus polysaccharide extract up to 72 hours. Specific enzymatic activities were assessed by kinetic measurements. The reduced glutathione content and the lipid peroxidation level were also analyzed. Protein expression of several heat shock proteins, Bcl-2 and metalloproteinases 2 and 9 were revealed by Western blot. Gelatin zymography assay was used to evaluate the MMP-2 and MMP-9 activities. Until the third day of exposure the total SOD activity decreased continuously by 30%, whereas GST and GR ones diminished by 17% respectively 30.5% compared to control. No significant changes were observed in CAT and G6PDH specific activities as well as in GSH and MDA concentration. After the third day of exposure a significant up-regulation of Hsp60 and Hsp90 expression and a down-regulation of Hsp70 one were registered. Bcl-2 protein levels were down-regulated by 50% in the first day of treatment but increased after 3 days. MMP-2 and 9 secretion in the culture medium was significantly reduced suggesting a diminished ability of invasion of colon cancer cells. Our data revealed that in vitro treatment with P. ostreatus aqueous polysaccharide extract does not induce apoptosis in Caco-2 cell line but it could inhibit the invasion of colon cancer cells through the basement membrane

AGEs and Glucose Levels Modulate Type I and III Procollagen mRNA Synthesis in Dermal Fibroblasts Cells Culture

In the dermis, fibroblasts play an important role in the turnover of the dermal extracellular matrix. Collagen I and III, the most important dermal proteins of the extracellular matrix, are progressively altered during ageing and diabetes. For mimicking diabetic conditions, the cultured human dermal fibroblasts were incubated with increasing amounts of AGE-modified BSA and D-glucose for 24 hours. The expression of procollagen α2(I) and procollagen α1(III) mRNA was analyzed by quantitative real-time PCR. Our data revealed that the treatment of fibroblasts with AGE-modified BSA upregulated the expression of procollagen α2(I) and procollagen α1(III) mRNA in a dose-dependent manner. High glucose levels mildly induced a profibrogenic pattern, increasing the procollagen α2(I) mRNA expression whereas there was a downregulation tendency of procollagen α1(III) mRNA

New Insights into the Biological Response Triggered by Dextran-Coated Maghemite Nanoparticles in Pancreatic Cancer Cells and Their Potential for Theranostic Applications

peer reviewedIron oxide nanoparticles are one of the most promising tools for theranostic applications of pancreatic cancer due to their unique physicochemical and magnetic properties making them suitable for both diagnosis and therapy. Thus, our study aimed to characterize the properties of dextran-coated iron oxide nanoparticles (DIO-NPs) of maghemite (γ-Fe2O3) type synthesized by co-precipitation and to investigate their effects (low-dose versus high-dose) on pancreatic cancer cells focusing on NP cellular uptake, MR contrast, and toxicological profile. This paper also addressed the modulation of heat shock proteins (HSPs) and p53 protein expression as well as the potential of DIO-NPs for theranostic purposes. DIO-NPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering analyses (DLS), and zeta potential. Pancreatic cancer cells (PANC-1 cell line) were exposed to different doses of dextran-coated ɣ-Fe2O3 NPs (14, 28, 42, 56 μg/mL) for up to 72 h. The results revealed that DIO-NPs with a hydrodynamic diameter of 16.3 nm produce a significant negative contrast using a 7 T MRI scanner correlated with dose-dependent cellular iron uptake and toxicity levels. We showed that DIO-NPs are biocompatible up to a concentration of 28 μg/mL (low-dose), while exposure to a concentration of 56 μg/mL (high-dose) caused a reduction in PANC-1 cell viability to 50% after 72 h by inducing reactive oxygen species (ROS) production, reduced glutathione (GSH) depletion, lipid peroxidation, enhancement of caspase-1 activity, and LDH release. An alteration in Hsp70 and Hsp90 protein expression was also observed. At low doses, these findings provide evidence that DIO-NPs could act as safe platforms in drug delivery, as well as antitumoral and imaging agents for theranostic uses in pancreatic cancer.2448 - TELEVIE-S SAUSSEZ- C Burtea - Theranostic approach for thyroïd cancer - Fédération Wallonie Bruxelle

Intoxication with some pesticides induce release of cytochrome C and DNA fragmentation in human cell line Huh 7

USMF „N. Testemiţanu” Catedra Biochimie şi Biochimie Clinică; Universitatea din Bucureşti, Facultatea de Biologie, Catedra BiochimieLindane and deltametrine are insecticides with very large utilization in agriculture and public health wich are dangerous contaminants for human organism. We studied the capacity of lindane and deltametrin to induce release of cytochrome C and DNA fragmentation in human cell line Huh 7, as a posibele mecanism of toxiticity. Our results sugest that intoxication with lindane and deltametrin induce biochemical modifications related to apoptosis. Lindanul şi deltametrinul sunt insecticide pe larg utilizate în agricultură şi sănătate publică, periculoase ca contaminanţi pentru organismul uman. Noi am studiat capacitatea acestor insecticide de a provoca eliberarea citocromului c şi fragmentatrea ADN în culturi de hepatocite umane transformate Huh7, ca un posibil mecanism al toxicităţii lor urmat de declansarea prcesului apoptotic. Rezultatele obţinute, sugerează că intoxicaţia cu aceste pesticide induce modificările biochimice caracteristice apoptozei

Biomedical properties and preparation of iron oxide-dextran nanostructures by MAPLE technique

<p>Abstract</p> <p>Background</p> <p>In this work the chemical structure of dextran-iron oxide thin films was reported. The films were obtained by MAPLE technique from composite targets containing 10 wt. % dextran with 1 and 5 wt.% iron oxide nanoparticles (IONPs). The IONPs were synthesized by co-precipitation method. A KrF* excimer laser source (λ = 248 nm, τ_FWHM≅25 ns, ν = 10 Hz) was used for the growth of the hybrid, iron oxide NPs-dextran thin films.</p> <p>Results</p> <p>Dextran coated iron oxide nanoparticles thin films were indexed into the spinel cubic lattice with a lattice parameter of 8.36 Å. The particle sized calculated was estimated at around 7.7 nm. The XPS shows that the binding energy of the Fe 2p_3/2of two thin films of dextran coated iron oxide is consistent with Fe³⁺oxides. The atomic percentage of the C, O and Fe are 66.71, 32.76 and 0.53 for the films deposited from composite targets containing 1 wt.% maghemite and 64.36, 33.92 and 1.72 respectively for the films deposited from composite targets containing 5 wt.% maghemite. In the case of cells cultivated on dextran coated 5% maghemite γ-Fe₂O₃, the number of cells and the level of F-actin were lower compared to the other two types of thin films and control.</p> <p>Conclusions</p> <p>The dextran-iron oxide continuous thin films obtained by MAPLE technique from composite targets containing 10 wt.% dextran as well as 1 and 5 wt.% iron oxide nanoparticles synthesized by co-precipitation method presented granular surface morphology. Our data proved a good viability of Hep G2 cells grown on dextran coated maghemite thin films. Also, no changes in cells morphology were noticed under phase contrast microscopy. The data strongly suggest the potential use of iron oxide-dextran nanocomposites as a potential marker for biomedical applications.</p

Biomedical Properties and Preparation of Iron Oxide-Dextran Nanostructures by MAPLE Technique

Background: In this work the chemical structure of dextran-iron oxide thin films was reported. The films were obtained by MAPLE technique from composite targets containing 10 wt. % dextran with 1 and 5 wt.% iron oxide nanoparticles (IONPs). The IONPs were synthesized by co-precipitation method. A KrF* excimer laser source (λ = 248 nm, τFWHM≅25 ns, ν = 10 Hz) was used for the growth of the hybrid, iron oxide NPs-dextran thin films. Results: Dextran coated iron oxide nanoparticles thin films were indexed into the spinel cubic lattice with a lattice parameter of 8.36 Å. The particle sized calculated was estimated at around 7.7 nm. The XPS shows that the binding energy of the Fe 2p3/2 of two thin films of dextran coated iron oxide is consistent with Fe3+ oxides. The atomic percentage of the C, O and Fe are 66.71, 32.76 and 0.53 for the films deposited from composite targets containing 1 wt.% maghemite and 64.36, 33.92 and 1.72 respectively for the films deposited from composite targets containing 5 wt.% maghemite. In the case of cells cultivated on dextran coated 5% maghemite γ-Fe2O3, the number of cells and the level of F-actin were lower compared to the other two types of thin films and control. Conclusions: The dextran-iron oxide continuous thin films obtained by MAPLE technique from composite targets containing 10 wt.% dextran as well as 1 and 5 wt.% iron oxide nanoparticles synthesized by co-precipitation method presented granular surface morphology. Our data proved a good viability of Hep G2 cells grown on dextran coated maghemite thin films. Also, no changes in cells morphology were noticed under phase contrast microscopy. The data strongly suggest the potential use of iron oxide-dextran nanocomposites as a potential marker for biomedical applications