Inoculation and bacterial analyses of fractions obtained from the reference inoculum TEC4 which experimentally reproduces epizootic rabbit enteropathy

[EN] The aetiology of epizootic rabbit enteropathy (ERE) is still unknown despite ten years of continuous research. A putative bacterial aetiology is the basis of current research. The fractionation of the reference inoculum (TEC4) is a major step towards finding the potential bacterial agent(s). In this study, TEC4 was fractionated by different techniques: centrifugation on discontinuous sucrose gradient, cell adherence and chloroform/ethanol treatment. The different fractions were inoculated into SPF rabbits and analyzed with classical bacteriological techniques. ERE was reproduced with two of the six fractions obtained. Four species never previously cultured from TEC were identified in the process but, to date, none of them seems to be the aetiology of ERE.This work was supported by a Grant from the «Service Publique Fédéral Santé Publique, sécurité de la chaîne alimentaire et environnement: Division Recherche contractuelle», contract RT 06/7 MINRABBIT. N. Huybens is a PhD fellow of the “Fonds pour la formation à la Recherche dans l’Industrie et dans l’Agriculture” (F.R.I.A.).Huybens, N.; Houeix, J.; Licois, D.; Mainil, J.; Marlier, D. (2009). Inoculation and bacterial analyses of fractions obtained from the reference inoculum TEC4 which experimentally reproduces epizootic rabbit enteropathy. World Rabbit Science. 17(4):185-193. https://doi.org/10.4995/wrs.2009.64318519317

Laser-synthesis of conductive carbon-based materials from two flexible commercial substrates: A comparison

One of the key challenges in the field of flexible electronics relies on finding conductive materials that can withstand bending and stretching stresses while maintaining their performance. In this context, this work presents a comparative study of laser-induced conductive materials from the direct laser-scribing of two commercial flexible films: the benchmark Kapton® HN polyimide (PI) precursor and the UltemTM 1000 polyetherimide (PEI) alternative contender. The synthesis process on both materials is optimized in terms of electrical conductivity using a high-performance galvanometric laser with a wavelength of 532 nm for the fabrication of multiple samples at different laser powers and speeds. The samples are structurally characterized using Scanning Electron Microscopy (SEM), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Fourier-Transform Infrared Spectroscopy (FTIR) aiming at understanding the chemical and physical changes of the ablated material. The results demonstrate that the proposed setup is feasible for the synthesis of uniform and reliable conductive patterns on the surface of both substrates with high reproducibility. In particular, it is proved that PEI is more suitable precursor for flexible electronics applications which demand high electrical conductivity, leading to a sheet resistance of 3.62 ± 0.35 Ω/sq at 0.8 W and 5 mm/s once the laser-synthesis process is optimized (against the 6.04 ± 0.63 Ω/sq at 0.6 W and 5 mm/s offered by the LIG on PI). The performance of both laser-induced patterns as electrodes for the fabrication of electrochemical capacitors is also studied and compared in terms of areal specific capacitance.FEDER/Junta de Andalucía-Consejería de Transformaci´on Econ´omica, IndustriaConocimiento y Universidades Project P20_00265 and Project BRNM-680-UGR20; Project TED2021-129949A-I00MCIN/AEI/10.13039/ 501100011033European Union NextGenerationEU/PRTRGrant PID2020-117344RB-I00MCIN/AEI 10.13039/ 501100011033Junta de Andalucía – Consejería de Universidad, Investigaci´on e Innovaci´on through the project ProyExcel_00268Spanish Ministry of Sciences and Innovation through the Ram´on y Cajal fellow RYC2019- 027457-I,María Zambrano fellow C21.I4.P1grant PRE2021-096886

Results of an inquiry about the quality of pig feeds in Brittany

International audienc

Pyrosequencing of epizootic rabbit enteropathy inocula and rabbit caecal samples.

peer reviewedaudience: researcher, professional, studentThe aetiological agent of epizootic rabbit enteropathy (ERE) is still unknown although a bacterial infection seems the most likely hypothesis. In this study, amplification of the V5 and V6 regions of 16SrDNA from four virulent and two non-virulent caecal samples was performed using a pyrosequencing platform. The virulent samples did not group in the same cluster. The bacterial flora identified was both different and richer than the cultivable bacterial flora. These findings highlight the need for biomolecular techniques to identify the aetiological agent of ERE

A cDNA microarray assessment of gene expression in the liver of rainbow trout (Oncorhynchus mykiss) in response to a handling and confinement stressor

A purpose-designed microarray platform (Stressgenes, Phase 1) was utilised to investigate the changes in gene expression within the liver of rainbow trout during exposure to a prolonged period of confinement. Tissue and blood samples were collected from trout at intervals up to 648 h after transfer to a standardised confinement stressor, together with matched samples from undisturbed control fish. Plasma ACTH, cortisol, glucose and lactate were analysed to confirm that the neuroendocrine response to confinement was consistent with previous findings and to provide a phenotypic context to assist interpretation of gene expression data. Liver samples for suppression subtractive hybridisation (SSH) library construction were selected from within the experimental groups comprising “early” stress (2–48 h) and “late” stress (96–504 h). In order to reduce redundancy within the four SSH libraries and yield a higher number of unique clones an additional subtraction was carried out. After printing of the arrays a series of 55 hybridisations were executed to cover 6 time points. At 2 h, 6 h, 24 h, 168 h and 504 h 5 individual confined fish and 5 individual control fish were used with control fish only at 0 h. A preliminary list of 314 clones considered differentially regulated over the complete time course was generated by a combination of data analysis approaches and the most significant gene expression changes were found to occur during the 24 h to 168 h time period with a general approach to control levels by 504 h. Few changes in expression were apparent over the first 6 h. The list of genes whose expression was significantly altered comprised predominantly genes belonging to the biological process category (response to stimulus) and one cellular component category (extracellular region) and were dominated by so-called acute phase proteins. Analysis of the gene expression profile in liver tissue during confinement revealed a number of significant clusters. The major patterns comprised genes that were up-regulated at 24 h and beyond, the primary examples being haptoglobin, β-fibrinogen and EST10729. Two representative genes from each of the six k-means clusters were validated by qPCR. Correlations between microarray and qPCR expression patterns were significant for most of the genes tested. qPCR analysis revealed that haptoglobin expression was up-regulated approximately 8-fold at 24 h and over 13-fold by 168 h.This project was part funded by the European Commission (Q5RS-2001-02211), Enterprise Ireland and the Natural Environment Research Council of the United Kingdom.peer-reviewe

Testes and brain gene expression in precocious male and adult maturing atlantic salmon (salmo salar)

Background: The male Atlantic salmon generally matures in fresh water upon returning after one or several years at sea. Some fast-growing male parr develop an alternative life strategy where they sexually mature before migrating to the oceans. These so called 'precocious' parr or 'sneakers' can successfully fertilise adult female eggs and so perpetuate their line. We have used a custom-built cDNA microarray to investigate gene expression changes occurring in the salmon gonad and brain associated with precocious maturation. The microarray has been populated with genes selected specifically for involvement in sexual maturation (precocious and adult) and in the parr-smolt transformation. Results: Immature and mature parr collected from a hatchery-reared stock in January were significantly different in weight, length and condition factor. Changes in brain expression were small - never more than 2-fold on the microarray, and down-regulation of genes was much more pronounced than up-regulation. Significantly changing genes included isotocin, vasotocin, cathepsin D, anamorsin and apolipoprotein E. Much greater changes in expression were seen in the testes. Among those genes in the testis with the most significant changes in expression were anti-Mullerian hormone, collagen 1A, and zinc finger protein (Zic1), which were down-regulated in precocity and apolipoproteins E and C-1, lipoprotein lipase and anti-leukoproteinase precursor which were up-regulated in precocity. Expression changes of several genes were confirmed in individual fish by quantitative PCR and several genes (anti-Mullerian hormone, collagen 1A, beta-globin and guanine nucleotide binding protein (G protein) beta polypeptide 2-like 1 (GNB2L1) were also examined in adult maturing testes. Down-regulation of anti-Mullerian hormone was judged to be greater than 160-fold for precocious males and greater than 230-fold for November adult testes in comparison to July testes by this method. For anti-Mullerian hormone and guanine nucleotide binding protein beta polypeptide 2-like 1 expression changes in precocious males mirrored mature adults (November) but for collagen 1A and beta-globin the pattern was more complex. Conclusions: Expression changes in the fish brain during the process of precocious sexual maturation were small compared to those in the testes. Microarray analysis suggested down-regulation of housekeeping functions and up-regulation of a small number of specific processes. Transcriptional changes in the testes were much more pronounced with anti-Mullerian hormone playing a major role. Expression profiles for mature parr and maturing adult testes indicate subtle differences in gene expression between these two related groups