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Toluene is a solvent widely produced and used by the industrial sector. Noise is a nuisance present in many professional sectors. We aimed to investigate in the present study the impact of exposure to toluene (300 ppm) and/or noise 85 dB(A) on rat heart and to assess the preventive effect of olive leaf extract OLE (40 mg/Kg/day) administrated for six weeks (5 days/week). Forty-eight male Wistar rats were divided into 8 groups (n = 6/group): C: control group, C+OLE: control group received OLE, N: group exposed to noise, N+OLE: group exposed to noise and received OLE, T: group exposed to toluene, T+OLE: group exposed to toluene and received OLE, NT: group co-exposed to noise and toluene, NT+OLE: group co-exposed to noise and toluene received. At the end of the experimental period, heart and blood samples were collected. Plasma cholesterol (CHOL), triglycerides (TG), lactate dehydrogenase (LDH) and creatine kinase (CK) levels were determined. Histopathological investigation was determined by HE staining. Superoxide dismutase (SOD), catalase (CAT) activities and malondialdehyde (MDA) level in heart tissue were also measured. Our results showed that Simultaneous exposure to noise and toluene altered CHOL, TG, LDH and CK levels. In parallel, an increase in lipid peroxidation levels and Superoxide dismutase activity with a decrease in catalase activity in the heart were shown. A significant alteration in the myocardium was also recorded. OLE treatment modulated theses oxidative and histological changes. In conclusion, OLE was found to correct the deleterious effects induced by combined exposure to noise and toluene.

Pyruvate is an essential metabolite produced by the glycolytic pathway in the cytosol and must be transported across the inner mitochondrial membrane (IMM) into the mitochondrial matrix, where it is oxidized to fuel mitochondrial respiration. Pyruvate import is performed by Mitochondrial Pyruvate Carrier (MPC), which is a hetero-oligomeric complex composed by interdependent subunits MPC1 and MPC2. Pathogenic variants in MPC1 gene disrupt mitochondrial pyruvate uptake and oxidation and it was associated to autosomal-recessive early-onset neurological dysfunction in humans. However, no pathogenic variants have been related to the MPC2 gene. The present work describes the first pathogenic variants in MPC2 associated with human disease in four patients from two unrelated families. In the first family, patients presented with antenatal developmental abnormalities, harbored a homozygous c.148T>C (p.Trp50Arg) variant. In the second family, patients presented with infantile encephalopathy carried missense c.2T>G (p.Met1?) variant disrupting the initiation codon. Patient-derived skin fibroblasts exhibit decreased pyruvate-driven oxygen consumption rates with normal activities of the pyruvate dehydrogenase complex and mitochondrial respiratory chain and no defects in mitochondrial content nor morphology. Re-expression of wild type MPC2 restored pyruvate-dependent respiration rates in patient-derived fibroblasts. The discovery of pathogenic variants in MPC2 therefore broadens the clinical and genetic landscape associated with inborn errors in pyruvate metabolism.

International audience; Engineered nanomaterials are used in various applications due to their particular properties. Among them, Iron Oxide Nanoparticles (Fe2O3-NPs) are used in Biomedicine as theranostic agents i.e. contrast agents in Magnetic Resonance Imaging and cancer treatment. With the increasing production and use of these Fe2O3-NPs, there is an evident raise of Fe2O3-NPs exposure and subsequently a higher risk of adverse outcomes for the environment and Human. In the present paper, we investigated the effects of an intravenous daily Fe2O3-NPs exposure on Wistar rat for one week. As results, we showed that several hematological parameters and transaminase (ALT and AST) levels as well as organ histology remained unchanged in treated rats. Neither the catecholamine levels nor the emotional behavior and learning / memory capacities of rats were impacted by the sub-acute intravenous exposure to Fe2O3-NPs. However, iron level in plasma and iron content homeostasis in brain were disrupted after this exposure. Thus, our results demonstrated that Fe2O3-NPs could have transient effects on rat but the intravenous route is still safer that others which is encouraging for their use in medical and/or biological applications.

International audience; Over the last decades, engineered nanomaterials have been widely used in various applications due to their interesting properties. Among them, iron oxide nanoparticles (IONPs) are used as theranostic agents for cancer, and also as contrast agents in magnetic resonance imaging. With the increasing production and use of these IONPs, there is an evident raise of IONP exposure and subsequently a higher risk of adverse outcome for humans and the environment. In this work, we aimed to investigate the effects of sub-acute IONP exposure on Wistar rat, particularly (i) on the emotional and learning/memory behavior, (ii) on the hematological and biochemical parameters, (iii) on the neurotransmitter content, and (vi) on the trace element homeostasis. Rats were treated during seven consecutive days by intranasal instillations at a dose of 10 mg/kg body weight. The mean body weight increased significantly in IONP-exposed rats. Moreover, several hematological parameters were normal in treated rats except the platelet count which was increased. The biochemical study revealed that phosphatase alkaline level decreased in IONP-exposed rats, but no changes were observed for the other hepatic enzymes (ALT and AST) levels. The trace element homeostasis was slightly modulated by IONP exposure. Sub-acute intranasal exposure to IONPs increased dopamine and norepinephrine levels in rat brain; however, it did not affect the emotional behavior, the anxiety index, and the learning/memory capacities of rats.

Iron Oxide Nanoparticles (IONPs) are used in several fields of application, mainly in the biomedical field for their magnetic properties and in food additive known as “E172” for their colour. In the present investigation, we focused on IONP effects on Wistar rat following acute oral exposure. We performed a multiscale physiopathological investigation in order to elucidate potential toxic effects linked to IONP ingestion, especially on cognitive capacities, trace element distribution, blood constituents, organ functions, organ structure and iron deposit. We demonstrated that oral exposure to IONPs induces disturbances of certain parameters depending on the dose. Interestingly, the histopathological examination evidenced inflammatory effects of IONPs in the liver with iron deposits in hepatocytes and Kuppfer cells. Neurobehavioral examination showed that oral exposure to IONPs did not affect nor rat emotions, exploration and locomotion capacities, nor spatial reference memory status. Furthermore, oral administration of IONPs did not disrupt the trace element homeostasis nor in the liver neither in the stomach. Altogether, our study evidenced low signs of toxicity, but some effects lead us to a careful use of these NPs. Thereby, their use in foods should be further studied to better evaluate the potential toxic risks of the oral exposure to IONPs.

A novel concept of membrane bioreactor based on polymeric ionic liquids laccase membrane has been implemented in batch process for decolorization of the anthraquinonic dye Remazol Brillant Blue R (RBBR). New laccase immobilization strategy has been optimized by casting the enzyme into a polymeric inclusion membrane (PIM) using ionic liquids (ILs) and polyvinyl chloride (PVC) leading to laccase polymeric IL membrane (PILM). Four different ILs (1-octyl-3-metylimidazolium bis(trifluoromethylsulfonyl)imide, [OMIM][NTF2]; cholinium bis(trifluoromethylsulfonyl)imide, [Ch ol][NTF2]; cholinium dihydrogenphosphate, [Chol][H2PO4] and hydroxyethylammonium formate, [HEA][Fo]) have been screened and mixed to constitute the active phase of the support of PIM. This strategy has been fully succeeded since high laccase immobilization rates were recorded (about 98%) when using the optimal mixture containing three ILs (45% [OMIM][NTf2]/5% [Chol][NTf2]/2.5% [HEA][Fo]) and supplemented by 0.5% glutaraldehyde. It was found that such mixture contributes to increase the stability and reusability of laccase-PILM during eight successive assays in a batch discontinued stirred reactor. Decolorization rate of 75% has been reached in the batch decolorization process of RBBR with high reusability yield.

Engineered nanomaterials are used in various applications due to their particular properties. Among them, Iron Oxide Nanoparticles (Fe

A single-chamber air-cathode microbial fuel cell (MFC) was successfully applied for decolorization of the diazoic dye Reactive Black 5 (RB5) with simultaneous production of electricity. An innovative low-cost medium, the marine water-glucose-yeast extract medium (MWGY), was developed which appears as a textile marine effluent in terms of salinity. The anode compartment containing a single bacterial strain of Stenotrophomonas sp. showed almost complete dye decolorization with different RB5 concentrations after seven days of treatment. For the four dye concentrations used, a correlation between dye removal and production of electrical energy was found. The comparison of the decolorization process in the MFC with that in a batch reactor as control experiment highlights the efficiency of the single-chamber air-cathode MFC technology which improved the dye removal by the same bacterial strain.

The use of a wide range of water miscible and immiscible ionic liquids (ILs) as reaction media for ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) oxidation by Trametes versicolor laccase was studied. Thirteen ILs were shown to be suitable media for the laccase oxidation reaction, increasing the activity with respect to conventional media. Among them, the water-miscible IL choline dihydrogen phosphate [Chol][H2PO4] allowed over-laccase activity with an enhancement rate of 451% at 25 °C and pH 7.0. This ionic liquid improved the stability of the enzyme in the face of high temperature and high pH, while storage at room temperature in aqueous medium was increased up to 4.5 times. Moreover, it was found that in the reaction medium for decolourizing dyes (antraquinonic and azoic) using laccase increased the decolourization rate by up to 216% and 137% for the azoic dyes Acid Black 1 and Remazol Brilliant Blue R, respectively. A high decolorization rate was also obtained for a mixture of dyes (80% within 8 h). To understand the effect of [Chol][H2PO4] on the secondary protein structure of the laccase, several spectroscopic techniques were used such as Circular Dichroism (CD), Fourier transform infrared (FT-IR) and Fluorescence, all of which demonstrated that the β sheet structure was affected. A shift to an α-helix structure [Chol][H2PO4] could be responsible for the enhancement of the enzyme activity observed at 300 mM.

BACKGROUND The bacterial Stenotrophomonas maltophilia AAP56 laccase (SmLac) has been purified from cell extracts and its spectral and kinetic properties studied. It shows a high decolorization rate (99%) of the diazoic dye Reactive Black 5 (RB5) in the presence of redox mediators such as ABTS (2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), ASGN (Acetosyringone), SGA (Syringaldehyde) and HOBT (1-Hydroxy-Benzotriazole). The optimal pH has been determined as neutral or basic compatible with textile wastewater pH for further treatment application. RESULTS This paper reports the characterization of the catalytic center of purified SmLac as not a classic blue laccase but a yellow one. Its redox potential has been determined at 638 mV, which indicates that the enzyme is a versatile laccase able to oxidase a wide range of substrates. Performance of the enzyme as catalyst for RB5 decolorization in association with a redox mediator has been demonstrated to be a promising bioremediation process since it presents high degradation ability (almost 99% in 1 h reaction time). The study also demonstrated, by electrochemical studies of redox potential of both mediators/protein and following the driving electron force, the importance of the choice of redox mediator and the limiting step in the laccase mediated reaction in azo dye decolorization. CONCLUSION It was demonstrated that the bacterial laccase SmLac has great potential for biotechnological applications (such as azo dye decolorization) compared with Trametes versicolor laccase. © 2013 Society of Chemical Industry

The fungus Sclerotinia sclerotiorum produces invertase activity during cultivation on many agroindustrial residues. The molasses induced invertase was purified by DEAE-cellulose chromatography. The molecular mass of the purified enzyme was estimated at 48 kDa. Optimal temperature was determined at 60 °C and thermal stability up to 65 °C. The enzyme was stable between pH 2.0 and 8.0; optimum pH was about 5.5. Apparent K(m) and V(max) for sucrose were estimated to be respectively 5.8 mM and 0.11 μmol/min. The invertase was activated by β-mercaptoethanol. Free enzyme exhibited 80 % of its original activity after two month's storage at 4 °C and 50 % after 1 week at 25 °C. In order to investigate an industrial application, the enzyme was immobilized on alginate and examined for invert sugar production by molasses hydrolysis in a continuous bioreactor. The yield of immobilized invertase was about 78 % and the activity yield was 59 %. Interestingly the immobilized enzyme hydrolyzed beet molasses consuming nearly all sucrose. It retained all of its initial activity after being used for 4 cycles and about 65 % at the sixth cycle. Regarding productivity; 20 g/l of molasses by-product gave the best invert sugar production 46.21 g/day/100 g substrate related to optimal sucrose conversion of 41.6 %.

A bacterial strain AAP56, isolated from a polluted soil (from Kelibia city) and identified as Stentrophomonas maltophilia, was particularly interesting for its ability to decolorize recalcitrant dyes of an industrial effluent: SITEX Black. The final percentage decolorization 60% was shown by bacterial culture after incubation in LB medium at 30°C under shaking conditions. The decolorization was closely correlated with the metabolic bacterial growth. The replacement of yeast extract in LB medium composition by soya flour was clearly efficient to enhance the percentage decolorization by 20% and also to reduce the growth medium cost 60-fold. The bacteria were able to reduce 23% from the initial COD and 28% from the initial BOD5 of the effluent. The immobilization of bacterial cells in calcium alginate beads improved by 25% the effectiveness of the biotransformation within 24 h in batch conditions. The potential of a downflow fixed column reactor (DFCR) to decolorize SITEX Black was evaluated under dilution rate. The best decolorization percentage (82%) was recorded at 0.3 h−1. This bioprocess seems to be a potentially useful method to remediate the colored textile wastewater.

Laccase activity was detected in a soil bacterium Stenotrophomonas maltophilia AAP56 identified by biochemical and molecular methods. It was produced in cells at the stationary growth phase in Luria Bertani (LB) medium added by 0.4 mM copper sulfate. The addition of CuSO4 in culture medium improved production of laccase activity. However, one laccase enzyme was detected by native polyacrylamide gel electrophoresis. The enzyme showed syringaldazine (K m = 53 μM), 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (K m = 700 μM), and pyrocatechol (K m = 25 μM) oxidase activity and was activated by addition of 0.1% (v/v) Triton-X-100 in the reaction mixture. Moreover, the laccase activity was increased 2.6-fold by the addition of 10 mM copper sulfate; the enzyme was totally inhibited by ethylenediaminetetraacetic acid (5 mM), suggesting that this laccase is a metal-dependant one. Decolorization activity of some synthetic dyes (methylene blue, methyl green, toluidine blue, Congo red, methyl orange, and pink) and the industrial effluent (SITEX Black) was achieved by the bacteria S. maltophilia AAP56 in the LB growth medium under shaking conditions.