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Alexandre-Gouabau MC - Courant F - Moyon T - Küster A - Le Gall G - Tea I - Antignac JP - Darmaun D
Maternal and Cord Blood LC-HRMS Metabolomics Reveal Alterations in Energy and Polyamine Metabolism, and Oxidative Stress in Very-low Birth Weight Infants.
Journal of Proteome Research
To assess the global effect of preterm birth on fetal metabolism and maternal−fetal nutrient transfer, we used a mass spectrometric-based chemical phenotyping approach on cord blood obtained at the time of birth. We sampled umbilical venous, umbilical arterial, and maternal blood from mothers delivering very-low birth weight (VLBW, with a median gestational age and weight of 29 weeks, and 1210 g, respectively) premature or full-term (FT) neonates. In VLBW group, we observed a significant elevation in the levels and maternal-fetal gradients of butyryl-, isovaleryl-, hexanoyl- and octanoyl-carnitines, suggesting enhanced short- and medium chain fatty acid β-oxidation in human preterm feto-placental unit. The significant decrease in glutamineglutamate in preterm arterial cord blood beside lower levels of amino acid precursors of Krebs cycle suggest increased glutamine utilization in the fast growing tissues of preterm fetus with a deregulation in placental glutamate-glutamine shuttling. Enhanced glutathione utilization is likely to account for the decrease in precursor amino acids (serine, betaine, glutamate and methionine) in arterial cord blood. An increase in both the circulating levels and maternal−fetal gradients of several polyamines in their acetylated form (diacetylspermine and acetylputrescine) suggests an enhanced polyamine metabolic cycling in extreme prematurity. Our metabolomics study allowed the identification of alterations in fetal energy, antioxidant defense, and polyamines and purines flux as a signature of premature birth. © 2013 American Chemical Society.

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Guibert E - Prieur B - Cariou R - Courant F - Antignac JP - Brillard JP - Froment P
Effects of Mono-(2-ethylhexyl) phthalate (MEHP) on chicken germ cells cultured in vitro.
Environmental Science and Pollution Research
In recent decades, many toxicological tests based on in vivo or in vitro models, mainly from mammalian (rat–mouse) and fish species, were used to assess the risks raised by contact or ingestion of molecules of pharmaceutical, agricultural, or natural origin. But no, or few, in vitro tests using other non-mammalian models such as bird have been explored despite their advantages: the embryonic gonads of birds have a high plasticity of development sensitive to estrogen, and sperm production is nearly two times faster than in rodents. Hence, we have established an in vitro culture of germ cells and somatic cells from chicken postnatal testis, and we have evaluated the sensitivity against the endocrine disruptor compound mono-(2-ethylhexyl) phthalate (MEHP) in comparison to previous studies using rodent and human models. After 96 h of exposure in presence of 10 μM MEHP, chicken seminiferous tubules cultures present a structural alteration, a reduction in cell proliferation and in germ cells population. Apoptosis of germ and somatic cells increases in presence of 1 μM MEHP. Furthermore, MEHP does not affect inhibin B and lactate production by Sertoli cells. These results are in accordance with previous studies using rat, mice, or human culture of testicular cells and in similar range of exposures or even better sensitivity for some “end-points” (biological parameters). In conclusion, the establishment of this postnatal testicular cells culture could be considered as an alternative method to in vivo experiments frequently used for evaluating the impact on the terrestrial wildlife species. This method could be also complementary to mammal model due to the limiting number of animals used and its elevated sensitivity. © Springer-Verlag Berlin Heidelberg 2013.

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La Merrill M - Emond C - Goldmann T - Antignac JP - Le Bizec B - Clément K - Barouki R
Toxicological function of adipose tissue: focus on persistent organic pollutants
Environmental Health Perspectives
Background: Adipose tissue (AT) is involved in several physiological functions, including metabolic regulation, energy storage, and endocrine functions. Objectives: In this review we examined the evidence that an additional function of AT is to modulate persistent organic pollutant (POP) toxicity through several mechanisms. Methods: We reviewed the literature on the interaction of AT with POPs to provide a comprehensive model for this additional function of AT. Discussion: As a storage compartment for lipophilic POPs, AT plays a critical role in the toxicokinetics of a variety of drugs and pollutants, in particular, POPs. By sequestering POPs, AT can protect other organs and tissues from POPs overload. However, this protective function could prove to be a threat in the long run. The accumulation of lipophilic POPs will increase total body burden. These accumulated POPs are slowly released into the bloodstream, and more so during weight loss. Thus, AT constitutes a continual source of internal exposure to POPs. In addition to its buffering function, AT is also a target of POPs and may mediate part of their metabolic effects. This is particularly relevant because many POPs induce obesogenic effects that may lead to quantitative and qualitative alterations of AT. Some POPs also induce a proinflammatory state in AT, which may lead to detrimental metabolic effects. Conclusion: AT appears to play diverse functions both as a modulator and as a target of POPs toxicity.

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Bourgin M - Gervais G - Bichon E - Antignac JP - Monteau F - Leroy G - Barritaud L - Chachignon M - Ingrand V - Roche P - Le Bizec B
Differential chemical profiling to identify ozonation by-products of estrone-sulfate and first characterization of estrogenicity in generated drinking water.
Water Research
For a few years, the concern of water treatment companies is not only focused on the removal of target micropollutants but has been extended to the investigation of potential biologically active by-products generated during the treatment processes. Therefore, some methods dedicated to the detection and structural characterization of such by-products have emerged. However, most of these studies are usually carried out under simplified conditions (e.g. high concentration levels of micropollutants, drastic treatment conditions, use of deionized or ultrapure water) and somewhat unrealistic conditions compared to that implemented in water treatment plants. In the present study, a real field water sample was fortified at the part-per-billion level (50 mg.L-1) with estrone-3-sulfate (E1-3S) before being ozonated (at 1 mg.L-1) for 10 min. In a first step, targeted measurements evidenced a degradation of the parent compound (>80%) in 10 min. Secondly, a non-targeted chemical profiling approach derived from metabolomic profiling studies allowed to reveal 11 ozonation by-products, among which 4 were found predominant. The estrogenic activity of these water samples spiked with E1-3S before and after treatment was assessed by the ERCALUX assay and was found to decrease significantly after 10 min of ozonation. Therefore, this innovative methodological strategy demonstrated its suitability and relevancy for revealing unknown compounds generated from water treatment, and permitted to generate new results regarding specifically the impact of ozonation on estrone-3-sulfate. These results confirm that ozonation is effective at removing E1-3S in drinking water and indicate that the by-products generated have significantly lower estrogenic activity. © 2013 Elsevier Ltd. All rights reserved.

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Doué M - Bichon E - Dervilly-Pinel G - Pichon V - Chapuis-Hugon F - Lesellier E - West C - Monteau F - Le Bizec B
Molecularly imprinted polymer applied to the selective isolation of urinary steroid hormones: an efficient tool in the control of natural steroid hormones abuse in cattle
Journal of Chromatography A
The use of anabolic substances to promote growth in livestock is prohibited within the European Union as laid down in Directive 96/22/EC. Nowadays, efficient methods such as steroid profiling or isotopic deviation measurements allow to control natural steroid hormones abuse. In both cases, urine is often selected as the most relevant matrix and, due to its relatively high content of potential interferents, its preparation before analysis is considered as a key step. In this context, the use of a selective sorbent such as molecularly imprinted polymer (MIP) was investigated. A MIP was synthesized based on 17-estradiol, methacrylic acid and acetonitrile as template, monomer and porogen, respectively. Two approaches were then tested for non-conjugated (aglycons and glucuronides deconjugated) steroid purification: (i) molecularly imprinted solid phase extraction (MISPE) and (ii) semi-preparative supercritical fluid chromatography with a commercial MIP as stationary phase (SFC–MIP). Parameters for both approaches were optimized based on the main bovine metabolites of testosterone, estradiol, nandrolone and boldenone. The MISPE protocol developed for screening purposes allowed satisfactory recoveries (upper 65% for the 12 target steroids) with sufficient purification for gas chromatography–mass spectrometry (GC–MS) analysis. For confirmatory purposes, the use of isotopic ratio mass spectrometry (IRMS) requires a higher degree of purity of the target compounds, which can be reached by the SFC–MIP protocol with three steps less compared to the official and current method. Purity, concentration and absence of isotopic fractionation of target steroids extracted from urine of treated cattle (treated with testosterone, estradiol, androstenedione, and boldenone) allowed the measurement of 13C/12C isotopic ratios of corresponding metabolites and endogenous reference compounds (ERC) and proved the relevance of the strategy. © 2012 Elsevier B.V. All rights reserved.

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Courant F - Royer AL - Morvan ML - Chéreau S - Monteau F - Antignac JP - Le Bizec B
Implementation of a semi‐automated strategy for the annotation of major compounds constituting metabolomic fingerprints generated by liquid chromatography ‐ high resolution mass spectrometry from biological samples
The Analyst
Metabolomics aims at detecting and semi-quantifying small molecular weight metabolites in biological samples in order to characterise the metabolic changes resulting from one or more given factors and/or to develop models based on diagnostic biomarker candidates. Nevertheless, whatever the objective of a metabolomic study, one critical step consists in the structural identification of mass spectrometric features revealed by statistical analysis and this remains a real challenge. Indeed, this requires both an understanding of the studied biological system, the correct use of various analytical information (retention time, molecular weight experimentally measured, isotopic golden rules, MS/MS fragment pattern interpretation.), or querying online databases. In gas chromatography-electro-ionisation (EI)-mass spectrometry, EI leads to a very reproducible fragmentation allowing establishment of universal EI mass spectra databases (for example, the NIST database – National Institute of Standards and Technology) and thus facilitates the identification step. Unfortunately, the situation is different when working with liquid chromatography-mass spectrometry (LC-MS) since atmospheric pressure ionisation exhibits high inter-instrument variability regarding fragmentation. Therefore, the constitution of LC-MS ‘‘in-house’’ spectral databases appears relevant in this context. The present study describes the procedure developed and applied to increment 133 and 130 metabolites in databanks dedicated to analyses performed with LC-HRMS in positive and negative electrospray ionisation, and the use of these databanks for annotating quickly untargeted metabolomics fingerprints. This study also describes the optimization of the parameters controlling the automatic processing in order to obtain a fast and reliable annotation of a maximum of organic compounds. This strategy was applied to bovine kidney samples collected from control animals or animals treated with steroid hormones. Thirty-eight compounds were identified successfully in the generated chemical phenotypes, among which five were found to be candidate markers of the administration of these anabolic agents, demonstrating the efficiency of the developed strategy to reveal and confirm metabolite structures according to the high-throughput objective expected from these integrative biological approaches.

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Suárez-Pantaleón C - Huet AC - Kavanagh O - Lei H - Dervilly-Pinel G - Le Bizec B - Situ C - Delahaut P
Production of specific polyclonal antibodies for the detection of recombinant bovine somatotropin
Analytica Chemica Acta
The administration of recombinant methionyl bovine somatotropin (rMbST) to dairy cows to increase milk yield remains a common practice in many countries including the USA, Brazil, Mexico, South Africa and Korea, whereas it has been forbidden within the European Union (EU) since 1999. A rapid screening immunoanalytical method capable of the unequivocal determination of rMbST in milk would be highly desirable in order to effectively monitor compliance with the EU-wide ban for home-made or imported dairy products. For decades, the production of specific antibodies for this recombinant isoform of bovine somatotropin (bST) has remained elusive, due to the high degree of sequence homology between both counterparts (e.g. methionine for rMbST in substitution of alanine in bST at the N-terminus). In this study, we compared several immunizing strategies for the production of specific polyclonal antibodies (pAbs), based on the use of the full-length recombinant protein, an rMbST N-terminus peptide fragment and a multiple antigen peptide (MAP) which consists of an oligomeric branching lysine core attached to the first two N-terminus amino acids of rMbST, methionine and phenylalanine (MF-MAP). The immunization with KLH-conjugated MF-MAP led to the production of the pAb with the highest rMbST/bST recognition ratio amongst the generated battery of antibodies. The pAb exhibited a specific binding ability to rMbST in a competitive antigen-coated ELISA format, which avidity was further improved after purification by rMbST N-terminus peptide-based affinity chromatography. These results suggest that immunodiscrimination between structurally related proteins can be achieved using immuno-enhanced immunogens such as MAPs. © 2012 Elsevier B.V. All rights reserved.

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Sirot V - Tard A - Marchand P - Venisseau A - Brosseaud A - Le Bizec B - Leblanc JP
Dietary exposure to polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls of the French population: results of the second French Total Diet Study
Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) bioaccumulate through the food chain and are therefore of public health concern. Exposure to these compounds was assessed in the second French Total Diet Study (TDS). Food samples (n = 583) were collected to be representative of the whole diet of the population, prepared as consumed, and analyzed. Contamination data were combined with national individual food consumption data. Mean exposure (95th percentile) to PCDD/F + DL-PCBs was assessed to be 0.57 (1.29) pg TEQWHO-98 (kg bw)-1 d-1 in the adult population and 0.89 (2.02) pg TEQWHO-98 (kg bw)-1 d-1 in the child and teenager population. Less than 4% of the population exceeded the health-based guidance value for PCDD/F + DL-PCBs. Mean exposure (95th percentile) to the six indicator PCBs (PCB 28, 52, 101, 138, 153, 180) was estimated at 2.71 (7.90) ng (kg bw)-1 d-1 in the adult population and 3.77 (11.7) ng (kg bw)-1 d-1 in the child and teenager population. Only 2.6% of the adults [CI95%: 1.9; 3.3] and 6.5% of the children and teenagers [5.2; 7.8] exceeded the health-based guidance value for total PCBs. These results show that the contamination levels in food and therefore the exposure of the general French population to PCDD/Fs and PCBs have declined (by a factor of 3.2 for PCDD/F + DL-PCBs and about three for total PCBs) since the last evaluation, which was conducted using another methodology in 2005 and 2007, and show the efficiency of the European risk management measures which came into force after these evaluations. © 2012 Elsevier Ltd. All rights reserved.

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Auger B - Pouvreau JB - Pouponneau K - Yoneyama K - Montiel G - Le Bizec B - Delavault P - Delourme R - Simier P
Germination stimulants of Phelipanche ramosa in the rhizosphere of Brassica napus are derived from the glucosinolate pathway
Molecular Plant-Microbe Interactions
Phelipanche ramosa is a major parasitic weed of Brassica napus. The first step in a host-parasitic plant interaction is stimulation of parasite seed germination by compounds released from host roots. However, germination stimulants produced by B. napus have not been identified yet. In this study, we characterized the germination stimulants that accumulate in B. napus roots and are released into the rhizosphere. Eight glucosinolate-breakdown products were identified and quantified in B. napus roots by gas chromatography–mass spectrometry. Two (3-phenylpropanenitrile and 2-phenylethyl isothiocyanate [2-PEITC]) were identified in the B. napus rhizosphere. Among glucosinolatebreakdown products, P. ramosa germination was strongly and specifically triggered by isothiocyanates, indicating that 2-PEITC, in particular, plays a key role in the B. napus– P. ramosa interaction. Known strigolactones were not detected by ultraperformance liquid chromatography–tandem mass spectrometry, and seed of Phelipanche and Orobanche spp. that respond to strigolactones but not to isothiocyanates did not germinate in the rhizosphere of B. napus. Furthermore, both wild-type and strigolactone biosynthesis mutants of Arabidopsis thaliana Atccd7 and Atccd8 induced similar levels of P. ramosa seed germination, suggesting that compounds other than strigolactone function as germination stimulants for P. ramosa in other Brassicaceae spp. Our results open perspectives on the high adaptation potential of root-parasitic plants under host-driven selection pressures. © The American Phytopathological Society, 2012.

2012; 4(1):1-11
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Dervilly-Pinel G - Courant F - Chéreau S - Royer AL - Boyard-Kieken F - Antignac JP - Monteau F - Le Bizec B
Metabolomics in food analysis: application to the control of forbidden substances
Drug Testing and Analysis

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