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El Khoury A.,Saint - Joseph University | Atoui A.,Lebanese Atomic Energy Commission CNRS | Rizk T.,Saint - Joseph University | Lteif R.,Saint - Joseph University | And 2 more authors.
Journal of Food Science | Year: 2011

Aflatoxins (AFs) represent the most important single mycotoxin-related food safety problem in developed and developing countries as they have adverse effects on human and animal health. They are produced mainly byAspergillus flavusandA. parasiticus. Both species have different aflatoxinogenic profile. In order to distinguish betweenA. flavusandA. parasiticus, gene-specific primers were designed to target the intergenic spacer (IGS) for the AF biosynthesis genes,aflJandaflR. Polymerase chain reaction (PCR) products were subjected to restriction endonuclease analysis usingBglIIto look for restriction fragment length polymorphisms (RFLPs). Our result showed that both species displayed different PCR-based RFLP (PCR-RFLP) profile. PCR products fromA. flavuscleaved into 3 fragments of 362, 210, and 102 bp. However, there is only one restriction site for this enzyme in the sequence ofA. parasiticusthat produced only 2 fragments of 363 and 311 bp. The method was successfully applied to contaminated grapes samples. This approach of differentiating these 2 species would be simpler, less costly, and quicker than conventional sequencing of PCR products and/or morphological identification. © 2011 Institute of Food Technologists®. Source

Rioult D.,University of Le Havre | Pasquier J.,University of Le Havre | Boulange-Lecomte C.,University of Le Havre | Poret A.,University of Le Havre | And 4 more authors.
Aquatic Toxicology | Year: 2014

In marine and estuarine species, immunotoxic and/or immunomodulatory mechanisms are the crossroad of interactions between xenobiotics, microorganisms and physicochemical variations of the environment. In mussels, immunity relies exclusively on innate responses carried out by cells collectively called hemocytes and found in the open hemolymphatic circulatory system of these organisms. However, hemocytes do not form a homogenous population of immune cells since distinct subtypes of mussel blood cells can be distinguished by cytochemistry, flow cytometry or cell motility analysis. Previous studies have also shown that these cells are able to efflux xenobiotics by means of ATP binding cassette (ABC) transporter activities conferring a multixenobiotic resistance (MXR) phenotype. ABC transporters corresponding to vertebrate class B/P-glycoprotein (P-gp) and to class C/multidrug resistance related protein (MRP) are characterized in Mytilidae. Herein, we have investigated the relative contributions of ABCB- and ABCC-mediated efflux within the different hemocyte subpopulations of Mytilus edulis mussels, collected from areas differentially impacted by chemical contaminants in Normandy (France). RT-PCR analyses provide evidence for the presence of ABCB and ABCC transporters transcripts in hemocytes. Immunodetection of ABCB/P-gp with the monoclonal antibody UIC2 in living hemocytes revealed that expression was restricted to granular structures of spread cells. Efflux transporter activities, with calcein-AM as fluorescent probe, were measured by combining flow cytometry to accurate Coulter cell size measurements in order to get a cell-volume normalized fluorescence concentration. In these conditions, basal fluorescence levels were higher in hemocytes originating from Yport (control site) than in cells collected from the harbor of Le Havre, where mussels are more exposed to with persistent pollutants. By using specific ABCB/P-gp (verapamil, PSC833, zosuquidar) and ABCC/MRP (MK571) blockers, we show that MXR activity is only carried out by MRP-type transporters in M. edulis hemocytes. In addition, cell-type-gated flow cytometry and calculation of the MXR activity factor indicate that ABCC-efflux activity is higher and more inducible in eosinophilic granulocytes than in other hemocyte subtypes. We conclude that, in the hemocytes of M. edulis, MXR phenotype is mediated by an ABCC/MRP-type transporter activity principally supported by eosinophilic granulocytes. A role for ABC transporters in hemocyte migration is discussed. © 2013 Elsevier B.V. Source

Soueidan M.,Lebanese Atomic Energy Commission CNRS | Nsouli B.,Lebanese Atomic Energy Commission CNRS | Ferro G.,CNRS Materials Sciences and Technologies Laboratory | Younes G.,Beirut Arab University
Materials Science Forum | Year: 2011

In this work the capability of the proton induced X-ray emission (PIXE) technique to monitor a rapid, non-destructive and accurate quantification of Al on and in Si-based matrix is discussed. Optimization of PIXE acquisition parameters was performed using as reference a thin Al film (2.5 nm) thermally evaporated onto silicon substrate. In order to improve the sensitivity for Al detection and quantitative determination, a systematic study was undertaken using proton ion beam at different energies (from 0.3 to 3 MeV) with a different tilting angle (0°, 60°, and 80°). The limit of detection (LOD) was found to be lower than 0.2 nm. The optimum PIXE conditions (energy, angle) were applied for determining the Al doping concentration in thin (1 μm) 4H-SiC homoepitaxial layer. The Al concentration as determined by PIXE was found to be 3.9×10 20 at/cm 3 in good agreement with SIMS measurements, and the LOD was estimated to be 6×10 18 at/cm 3. © (2011) Trans Tech Publications. Source

el Khoury A.E.,Saint - Joseph University | Atoui A.,Lebanese Atomic Energy Commission CNRS
Toxins | Year: 2010

Ochratoxin A (OTA) is a mycotoxin produced by several species of Aspergillus and Penicillium fungi that structurally consists of a para-chlorophenolic group containing a dihydroisocoumarin moiety that is amide-linked to L-phenylalanine. OTA is detected worldwide in various food and feed sources. Studies show that this molecule can have several toxicological effects such as nephrotoxic, hepatotoxic, neurotoxic, teratogenic and immunotoxic. A role in the etiology of Balkan endemic nephropathy and its association to urinary tract tumors has been also proved. In this review, we will explore the general aspect of OTA: physico-chemical properties, toxicological profile, OTA producing fungi, contaminated food, regulation, legislation and analytical methods. Due to lack of sufficient information related to the molecular background, this paper will discuss in detail the recent advances in molecular biology of OTA biosynthesis, based on information and on new data about identification and characterization of ochratoxin biosynthetic genes in both Penicillium and Aspergillus species. This review will also cover the development of the molecular methods for the detection and quantification of OTA producing fungi in various foodstuffs. © 2010 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland. Source

Abboudy S.,Beirut Arab University | Abboudy S.,Alexandria University | Soueidan M.,Lebanese Atomic Energy Commission CNRS | Soueidan M.,CNRS Ampere Laboratory | And 6 more authors.
Advanced Materials Research | Year: 2011

In this work, the capability of the proton Induced γ-ray Emission (PIGE) technique to monitor a rapid, nondestructive and quantification of Boron in ultra-thin films of B xGa 1-xAs deposited on GaAs substrate using MOCVD is discussed. In order to improve the sensitivity for B detection, a systematic study was undertaken using proton induced beam at three different energies (from 1.7, 2.4 and 3 MeV) with different tilting angles (0, 60° and 80°). Best conditions were found to be at 1.7 MeV and at 80° for proton energy and tilting angle within ten minutes of acquisition time. © (2011) Trans Tech Publications, Switzerland. Source

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