C-banding in sheep with balanced homolog interchromosomal translocation

International audienc

G-banding and fluorescent-banding in sheep with heterozygous and homozygous translocation

International audienc

Iron bioavailability in two commercial cultivars of wheat: a comparison between wholegrain and white flour and the effects of nicotianamine and 2'-deoxymugineic acid on iron uptake into Caco-2 cells

Iron bioavailability in unleavened white and wholegrain bread made from two commercial wheat varieties was assessed by measuring ferritin production in Caco-2 cells. The breads were subjected to simulated gastrointestinal digestion and the digests applied to the Caco-2 cells. Although Riband grain contained a lower iron concentration than Rialto, iron bioavailability was higher. No iron was taken up by the cells from white bread made from Rialto flour or from wholegrain bread from either variety, but Riband white bread produced a small ferritin response. The results probably relate to differences in phytate content of the breads, although iron in soluble monoferric phytate was demonstrated to be bioavailable in the cell model. Nicotianamine, an iron chelator in plants involved in iron transport, was a more potent enhancer of iron uptake into Caco-2 cells than ascorbic acid or 2'-deoxymugineic acid, another metal chelator present in plants

Scale effect in hazard assessment - application to daily rainfall

International audienceDaily precipitation is recorded as the total amount of water collected by a rain-gauge in 24h. Events are modelled as a Poisson process and the 24h precipitation by a Generalized Pareto Distribution (GPD) of excesses. Hazard assessment is complete when estimates of the Poisson rate and the distribution parameters, together with a measure of their uncertainty, are obtained. The shape parameter of the GPD determines the support of the variable: Weibull domain of attraction (DA) corresponds to finite support variables, as should be for natural phenomena. However, Fréchet DA has been reported for daily precipitation, which implies an infinite support and a heavy-tailed distribution. We use the fact that a log-scale is better suited to the type of variable analyzed to overcome this inconsistency, thus showing that using the appropriate natural scale can be extremely important for proper hazard assessment. The approach is illustrated with precipitation data from the Eastern coast of the Iberian Peninsula affected by severe convective precipitation. The estimation is carried out by using Bayesian techniques

Biophysical Factors Impacting Sea Lice Settlement and Survival

Atlantic salmon (Salmo salar L.) aquaculture production in Maine is a valuable contributor to the economy, the expansion of which has been challenged by the parasitic salmon louse Lepeophtheirus salmonis. As planktonic organisms, the life of the salmon louse is primarily dictated by the physical conditions of the environment: the temperature for development time, salinity for survival, and current velocity for transport. Salmon lice are obligate parasites for whom the successful infection of a suitable host is critical to completion of their life cycle. However, little is understood about the effects of current velocity on infection success. Hydrodynamic models are tools that describe the physical conditions of the marine environment and have been combined with particle tracking models to predict the dispersal of sea lice in salmon-farming areas in other countries, including Norway, Scotland, Canada, and the Faroe Islands. These models vary in scope, however, many lack a parameter for the effect of velocity on attachment. The purpose of the experiments conducted as part of this thesis is to provide such a parameter for inclusion in a model for sea lice dispersal in Cobscook Bay, one of the primary sites of net pen salmon farming in the United States. PIT-tagged Atlantic salmon were challenged with a standardized dose of salmon lice at low, moderate, and high current velocities commonly experienced by salmon in net-pens in Cobscook Bay at 5, 10, and 15 cm sec-1 (0.10, 0.19, and 0.29 knots), respectively. Mean percent settlement was calculated for each velocity group, and a permutation-based ANOVA was conducted to determine if significant differences existed between groups. Percent settlement was significantly different in all three velocity groups, with optimum settlement occurring at moderate velocity, with high velocity resulting in the lowest average settlement success. The results of this study exhibit similar patterns to what has been observed in other studies and are discussed with respect to sentinel cage surveys previously conducted in Cobscook Bay

Graphics for relatedness research

Studies of relatedness have been crucial in molecular ecology over the last decades. Good evidence of this is the fact that studies of population structure, evolution of social behaviours, genetic diversity and quantitative genetics all involve relatedness research. The main aim of this article is to review the most common graphical methods used in allele sharing studies for detecting and identifying family relationships. Both IBS and IBD based allele sharing studies are considered. Furthermore, we propose two additional graphical methods from the field of compositional data analysis: the ternary diagram and scatterplots of isometric log-ratios of IBS and IBD probabilities. We illustrate all graphical tools with genetic data from the HGDP-CEPH diversity panel, using mainly 377 microsatellites genotyped for 25 individuals from the Maya population of this panel. We enhance all graphics with convex hulls obtained by simulation and use these to confirm the documented relationships. The proposed compositional graphics are shown to be useful in relatedness research, as they also single out the most prominent related pairs. The ternary diagram is advocated for its ability to display all three allele sharing probabilities simultaneously. The log-ratio plots are advocated as an attempt to overcome the problems with the Euclidean distance interpretation in the classical graphics.Peer ReviewedPostprint (published version

Iron bioavailability in low phytate pea

Non-Peer ReviewedThe objectives of this study are to determine the effect of genotype and environment on iron bioavailability in a set of five pea varieties differing in phytate concentration using the in vitro digestion/Caco-2 human cell assay (Glahn 2009), to determine whether iron bioavailability in field pea is heritable by evaluating recombinant inbred lines (RILs) differing in phytate concentration using in vitro digestion/Caco-2 human cell assay, and to determine the effect of the pea low phytate trait on chicken performance and iron bioavailability in chicken. In a previous study, two low phytate pea lines (1-2347-144 and 1-150-81) were developed from CDC Bronco at the Crop Development Centre, University of Saskatchewan (Warkentin et al. 2012). As a powerful chelator of iron, phytate can reduce the iron bioavailability in diets. The low phytate peas may have increased iron bioavailability compared to the normal phytate peas. In the first objective of this project, the iron bioavailability of pea seeds of the two low phytate lines, their parent CDC Bronco and two other popular pea varieties in western Canada (CDC Meadow and CDC Golden), derived from 3 replicate field experiments conducted in 2009 and 2010 at SPG (Saskatchewan Pulse Growers land), Outlook and Rosthern, were assessed using the in vitro digestion/Caco-2 cell culture. The result shows that the iron bioavailability of the two low phytate lines is significantly higher than the other three normal phytate varieties, although their iron concentrations have not significant difference. The low phytate line 1-2347-144 and CDC Meadow were crossed to develop RILs