First insights into serum metabolomics of trenbolone/estradiol implanted bovines; screening model to predict hormone-treated and control animals’ status

International audienceThe use of anabolic agents in livestock production is a subject of much concern. Although prohibited for more than 20&nbsp;years within the EU, growth promoting practices are still widely suspected. To meet the current challenges for detecting illicit practices, ‘omics’ strategies have recently been demonstrated as important new investigative tools. These investigations, based on the observation of physiological disturbances, mainly in urine, demonstrated the possibility to monitor biomarkers enabling high throughput determination of animal status in terms of hormonal treatment. In this context, serum was investigated for the first time as an alternative and potential complementary sample type. A metabolomic approach based on liquid chromatography coupled to high resolution mass spectrometry, was exploited in order to, highlight metabolic perturbations in serum of Revalor-XS® (trenbolone acetate/estradiol) implanted bovines. Univariate and multivariate statistical analyses were carried out to establish descriptive and predictive models. These models enabled the discrimination of anabolised from control animals, and highlighted a number of metabolites which contributed the most in the observed discrimination. Further, a screening model combining a set of selected markers intensities was generated and it successfuly classified animals according to their status, up to 4&nbsp;weeks post Revalor-XS® implant. This research indicates, for the first time, that serum metabolomics has an important role in screening to detect for anabolic misuse in bovines.</p

Mixture Risk Assessment of Complex Real-Life Mixtures—The PANORAMIX Project

Humans are involuntarily exposed to hundreds of chemicals that either contaminate our environment and food or are added intentionally to our daily products. These complex mixtures of chemicals may pose a risk to human health. One of the goals of the European Union’s Green Deal and zero-pollution ambition for a toxic-free environment is to tackle the existent gaps in chemical mixture risk assessment by providing scientific grounds that support the implementation of adequate regulatory measures within the EU. We suggest dealing with this challenge by: (1) characterising ‘real-life’ chemical mixtures and determining to what extent they are transferred from the environment to humans via food and water, and from the mother to the foetus; (2) establishing a high-throughput whole-mixture-based in vitro strategy for screening of real-life complex mixtures of organic chemicals extracted from humans using integrated chemical profiling (suspect screening) together with effect-directed analysis; (3) evaluating which human blood levels of chemical mixtures might be of concern for children’s development; and (4) developing a web-based, ready-to-use interface that integrates hazard and exposure data to enable component-based mixture risk estimation. These concepts form the basis of the Green Deal project PANORAMIX, whose ultimate goal is to progress mixture risk assessment of chemicals.Horizon 2020 research and innovation programme, the Green Deal project PANORAMIX Grant Agreement No. 10103663

Production of polyclonal antibodies directed to recombinant methionyl bovine somatotropin

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

Aminoaciduria caused by fanconi syndrome in a heifer

A case study of renal tubular dysfunction consistent with idiopathic Fanconi syndrome is reported in an 18-month-old Holstein heifer. The clinical, biochemical, and histopathological features are described. The heifer had clinical signs of growth retardation, wasting, and persistent diarrhea. Biochemical blood analysis identified hypokalemia, hyponatremia, and hypo-chloremia. Urinalysis identified glycosuria, proteinuria, and acidic pH. Histological examination of the kidney disclosed mild tubular necrosis with proteinaceous casts in the lumina of renal tubules. We performed LC-HRMS on urine to confirm Fanconi syndrome. Using this technique, we identified severe generalized aminoaciduria suggestive of idiopathic renal Fanconi syndrome in this heifer

Specificity of monoclonal antibodies generated against arabinoxylans of cereal grains

TY - JOURInternational audienceXylooligosaccharides substituted by arabinose have been produced by degradation of wheat flour arabinoxylans with an endoxylanase. These oligosaccharides were coupled to carrier proteins (KLH and BSA) and three monoclonal antibodies were isolated. The specificity of antibody recognition was studied using arabino-xylo-oligosaccharides exhibiting different pattern of substitution by arabinose.ELISA competition tests and molecular modelling suggest that the conformation adopted by beta-(1->4) linked xylose residues is an antigenic determinant recognized by the different antibodies. Arabinose was not specifically involved in the interaction of antibody and epitope

Occurrence du Déchlorane plus et de composés apparentés chez des silures (Silurus spp.) provenant de rivières françaises

International audienceDechlorane related compounds (DRCs), including Dechlorane Plus (syn-DP and anti-DP), Dechlorane-601,-602, -603 and Chlordene Plus (CP), constitute a group of polychlorinated flame retardants (FRs) that are still of industrial use. In particular, DRCs have been detected in various nvironmental matrices and in different aquatic and terrestrial biota, thus exhibiting bioaccumulation and biomagnification potentials. The present study aimed at producing first occurrence data of a range of DRCs in Silurus spp. samples from different rivers located in France. Determination was carried out by gas chromatography high-resolution mass spectrometry after a sample clean-up based on a multilayer silica column and gel permeation chromatography. The concentration of monitored SDRCs ranged from 1.58 to 408 pg.g-1 wet weight (54 - 11100 pg.g-1 lipid weight). The fractional abundance of syn- and anti-DP stereoisomers was similar to that reported by other studies with an average equal to 0.60. Dec-601 was not detected in any sample. Detection frequencies ranged between 34 and 100% for other DRCs. Investigated correlations between DRCs and polychlorobiphenyls (PCBs) suggest a link with lipid content but independent contamination sources

Profiling of transcriptional biomarkers in FFPE liver samples: PLS-DA applications for detection of illicit administration of sex steroids and clenbuterol in veal calves

Administering growth promoters to meat-producing animals is strictly regulated within the European Community to preserve consumers' safety. Nevertheless, illicit misuse of steroids and other veterinary drugs to increase animal production has still been found by National Residues Control Plans (NRCPs), mainly based on expensive targeted multi-class/multi-residue analytical methods, used for confirming quantification analysis of these residues in tissues and biological fluids. The setup of complementary novel diagnostic methods, based on indirect biomarkers of exposure to anabolic substances is, therefore, needed to update current tests available in NRCPs at the screening level, where cheaper, sensitive and untargeted methods are required. Biological effects of illicit treatment transcriptomic analysis has reached a good grade of standardization, identified by microarray and RNAseq technologies of large panels of differentially expressed gene targets (DEG) related to abuse of different classes of anabolic molecules (e.g. sex steroids, thyreostats, beta 2-agonists, glucocorticoids, etc.). The aim of the work was to identify a minimum set of molecular markers able to detect illicit administration of two of the most recurrent classes of growth promoters (sex steroids and B2-agonists) on formalin-fixed paraffin-embedded (FFPE) tissues, being a potentially straightforward sampling strategy at the slaughterhouse level. A PCR array to allow quantitative profiling of 48 genetic targets was, therefore, developed on FFPE liver samples from veal calves. Conventional univariate and alternative approaches based on multivariate classification methods were considered for gene expression profiling of 92 samples collected from different animal trials, where effects of nandrolone, estradiol, their combination, and clenbuterol were studied.The developed Partial Least Squares-Discriminant Analysis (PLS-DA) models show the successful setup of a novel screening strategy based on multiple transcriptional biomarkers, able to expand tested sample sizes, and consequently strengthen current NRCPs