Effet de la fréquence de récolte et des milieux de dilution sur la qualité du sperme de taureau de race Borgou

La présente étude a pour but d’évaluer la production et la qualité de sperme de 17 taureaux Borgou. L’expérimentation a été réalisée sur la base des séances de récolte tous les 4 jours, pendant 36 jours au cours desquels l’efficacité in vitro de six milieux de dilution sur la motilité et la vitalité des spermatozoïdes (spz) a été testée pendant 28 jours. Les résultats ont montré que la fréquence de récolte expérimentée n’affecte pas la qualité des éjaculats qu’on pourrait utiliser pour l’insémination artificielle à l’état frais (+5 °C). L’effet des différents dilueurs sur la motilité et la viabilité des spermatozoïdes, a prouvé que ces spermatozoïdes supportaient moins bien le milieu à base de lait de coco que ceux à base de jaune d’oeuf et de lait de vache. Cependant, tous les milieux de dilution testés peuvent être utilisés pour conserver les semences +5 °C durant 48 heures. La durée de conservation peut être étendue à 72 heures pour le lait de vache et le jaune d’oeuf.Mots clés: Sperme, insémination artificielle, dilueurs, éjaculats, bovin, Beni

Presence of intestinal Mycobacterium avium subspecies paratuberculosis (MAP) DNA is not associated with altered MMP expression in ulcerative colitis

<p>Abstract</p> <p>Background</p> <p><it>Mycobacterium avium </it>subspecies <it>paratuberculosis </it>(MAP) is suspected to be a causative agent in human Crohn's disease (CD). Recent evidence suggests that pathogenic mycobacteria and MAP can induce the expression of Matrix Metalloproteinases (MMP), which are the main proteases in the pathogenesis of mucosal ulcerations in inflammatory bowel disease (IBD). Within this study we assessed the prevalence of intestinal MAP specific DNA in patients with Crohn's disease, ulcerative colitis (UC), and healthy controls. We further analysed regulation patterns of MMPs in mucosal tissues of UC patients with and without intestinal MAP DNA detection.</p> <p>Methods</p> <p>Colonic biopsy samples were obtained from 63 Norwegian and German IBD patients and 21 healthy controls. RNA was quantified by quantitative real-time polymerase chain reaction (PCR) to study MMP gene expression in both pathological and healthy mucosal specimens. The presence of MAP DNA in colonic mucosa was examined using MAP specific PCR.</p> <p>Results</p> <p>MAP DNA was detected in 20% of UC patients and 33% of healthy controls but only in 7% of patients with CD. UC patients treated with corticosteroids exhibited a significantly increased frequency of intestinal MAP DNA compared to those not receiving corticosteroids. Expression of MMP-1, -2, -7, -9, -13, -19, -28 and TNF-α did not differ between UC patients with presence of intestinal MAP DNA compared to those without. MMP-2, MMP-9 and MMP-13 were significantly decreased in UC patients receiving corticosteroids.</p> <p>Conclusions</p> <p>The presence of intestinal MAP specific DNA is not associated with altered MMP expression in UC <it>in vivo</it>. Corticosteroids are associated with increased detection of intestinal MAP DNA and decreased expression of certain MMPs. Frequent detection of MAP DNA in healthy controls might be attributable to the wide environmental distribution of MAP and its presence in the food-chain.</p

The anti-bacterial iron-restriction defence mechanisms of egg white; the potential role of three lipocalin-like proteins in resistance against Salmonella

Salmonella enterica serovar Enteritidis (SE) is the most frequently-detected Salmonella in foodborne outbreaks in the European Union. Among such outbreaks, egg and egg products were identified as the most common vehicles of infection. Possibly, the major antibacterial property of egg white is iron restriction, which results from the presence of the iron-binding protein, ovotransferrin. To circumvent iron restriction, SE synthesise catecholate siderophores (i.e. enterobactin and salmochelin) that can chelate iron from host iron-binding proteins. Here, we highlight the role of lipocalin-like proteins found in egg white that could enhance egg-white iron restriction through sequestration of certain siderophores, including enterobactin. Indeed, it is now apparent that the egg-white lipocalin, Ex-FABP, can inhibit bacterial growth via its siderophore-binding capacity in vitro. However, it remains unclear whether ex-FABP performs such a function in egg white or during bird infection. Regarding the two other lipocalins of egg white (Cal-γ and α-1-glycoprotein), there is currently no evidence to indicate that they sequester siderophores

Degree of simulated suppression of Atlantic tropical cyclones modulated by flavour of El Niño

El Nino/Southern Oscillation, the dominant mode of interannual climate variability, strongly influences tropical cyclone activity. During canonical El Nino, the warm phase, Atlantic tropical cyclones are suppressed. However, the past decades have witnessed different El Nino characteristics, ranging from warming over the east Pacific cold tongue in canonical events to warming near the warm pool, known as warm pool El Nino or central Pacific El Nino. Global climate models project possible future increases in intensity of warm pool El Nino. Here we use a climate model at a resolution sufficient to explicitly simulate tropical cyclones to investigate how these flavours of El Nino may affect such cyclones. We show that Atlantic tropical cyclones are suppressed regardless of El Nino type. For the warmest 10% of each El Nino flavour, warm pool El Nino is substantially less effective at suppressing Atlantic tropical cyclones than cold tongue El Nino. However, for the same absolute warming intensity, the opposite is true. This is because less warming is required near the warm pool to satisfy the sea surface temperature threshold for deep convection, which leads to tropical cyclone suppression through vertical wind shear enhancements. We conclude that an understanding of future changes in not only location, but also intensity and frequency, of El Nino is important for forecasts and projections of Atlantic tropical cyclone activity