A prospective cohort study of digital cushion and corium thickness, Part 1: associations with body condition, lesion incidence and proximity to calving

Claw horn disruption lesions (CHDL) are a major cause of lameness in dairy cattle and are likely a result of excessive forces being applied to the germinal epithelium that produces claw horn. The digital cushion is a connective tissue structure, containing depots of adipose tissue, that sits beneath the distal phalanx and has been shown to be thicker in fatter cows. Body condition score (BCS) loss is a risk factor for CHDL, and one possible explanation is that fat is mobilised from the digital cushion during negative energy balance, causing the digital cushion to thin and lose force dissipating capacity, leading to disruption of claw horn growth. This prospective cohort study investigated the association between measures of body fat and sole soft tissues (SST) thickness (a combined measure of the corium and digital cushion beneath the distal phalanx) in a longitudinal manner. SST of 179 cows in two high yielding dairy herds were measured at five assessment points between 8 weeks prior to and 35 weeks post calving. BCS, back fat thickness (BFT) and lesion incidence were recorded. Data were analysed in a 4-level mixed effects regression model, with the outcome being SST thickness beneath the flexor tuberosity of the distal phalanx. Data from 827 assessment points were available for analysis. The overall mean of SST was 4.99 mm (SD: 0.95). SST was thickest 8 weeks prior to calving (5.22 mm, SD: 0.91) and thinnest one week post-calving (4.68 mm, SD: 0.87), suggesting that there was an effect of calving on SST. BFT was positively correlated with SST in the model with a small effect size (a 10 mm decrease in BFT corresponded with a 0.13 mm decrease in SST), yet the nadir of BFT was 11.0 mm at 9-17 weeks post calving (when SST was ~4.95 mm), rather than occurring with the nadir of SST immediately after calving. SST also varied with other variables, e.g. cows that developed a sole ulcer or severe sole haemorrhage during the study had thinner SST (-0.24 mm), except when a sole ulcer was present, when it was thicker (+0.53 mm). Cows that developed lesions had a thinner digital cushion prior to the lesion occurrence, which became thickened with sole ulcer presence, perhaps representing inflammation. Further, whilst BFT was correlated with SST over time, SST may also have been influenced by other factors such as integrity of the suspensory apparatus, which could have a major effect on CHDL. Measures of body fat likely contributed to having thin SST, but other factors including calving, herd and lesion presence also had an effec

Native drivers of fish life history traits are lost during the invasion process

Rapid adaptation to global change can counter vulnerability of species to population declines and extinction. Theoretically, under such circumstances both genetic variation and phenotypic plasticity can maintain population fitness, but empirical support for this is currently limited. Here, we aim to characterize the role of environmental and genetic diversity, and their prior evolutionary history (via haplogroup profiles) in shaping patterns of life history traits during biological invasion. Data were derived from both genetic and life history traits including a morphological analysis of 29 native and invasive populations of topmouth gudgeon Pseudorasbora parva coupled with climatic variables from each location. General additive models were constructed to explain distribution of somatic growth rate (SGR) data across native and invasive ranges, with model selection performed using Akaike's information criteria. Genetic and environmental drivers that structured the life history of populations in their native range were less influential in their invasive populations. For some vertebrates at least, fitness-related trait shifts do not seem to be dependent on the level of genetic diversity or haplogroup makeup of the initial introduced propagule, nor of the availability of local environmental conditions being similar to those experienced in their native range. As long as local conditions are not beyond the species physiological threshold, its local establishment and invasive potential are likely to be determined by local drivers, such as density-dependent effects linked to resource availability or to local biotic resistance

Cutting edge: Langerin+ dendritic cells in the mesenteric lymph node set the stage for skin and gut immune system cross-talk.

International audienceTopical transcutaneous immunization (TCI) presents many clinical advantages, but its underlying mechanism remains unknown. TCI induced Ag-specific IgA Ab-secreting cells expressing CCR9 and CCR10 in the small intestine in a retinoic acid-dependent manner. These intestinal IgA Abs were maintained in Peyer's patch-null mice but abolished in the Peyer's patch- and lymph node-null mice. The mesenteric lymph node (MLN) was shown to be the site of IgA isotype class switching after TCI. Unexpectedly, langerin(+)CD8alpha(-) dendritic cells emerged in the MLN after TCI; they did not migrate from the skin but rather differentiated rapidly from bone marrow precursors. Depletion of langerin(+) cells impaired intestinal IgA Ab responses after TCI. Taken together, these findings suggest that MLN is indispensable for the induction of intestinal IgA Abs following skin immunization and that cross-talk between the skin and gut immune systems might be mediated by langerin(+) dendritic cells in the MLN

Native drivers of fish life history traits are lost during the invasion process

Rapid adaptation to global change can counter vulnerability of species to population declines and extinction. Theoretically, under such circumstances both genetic variation and phenotypic plasticity can maintain population fitness, but empirical support for this is currently limited. Here, we aim to characterize the role of environmental and genetic diversity, and their prior evolutionary history (via haplogroup profiles) in shaping patterns of life history traits during biological invasion. Data were derived from both genetic and life history traits including a morphological analysis of 29 native and invasive populations of topmouth gudgeon Pseudorasbora parva coupled with climatic variables from each location. General additive models were constructed to explain distribution of somatic growth rate (SGR) data across native and invasive ranges, with model selection performed using Akaike's information criteria. Genetic and environmental drivers that structured the life history of populations in their native range were less influential in their invasive populations. For some vertebrates at least, fitness-related trait shifts do not seem to be dependent on the level of genetic diversity or haplogroup makeup of the initial introduced propagule, nor of the availability of local environmental conditions being similar to those experienced in their native range. As long as local conditions are not beyond the species physiological threshold, its local establishment and invasive potential are likely to be determined by local drivers, such as density-dependent effects linked to resource availability or to local biotic resistance

Thermal Parameters and Microstructural Development in Directionally Solidified Zn-Rich Zn-Mg Alloys

Transient directional solidification experiments have been carried out with Zn-Mg hypoeutectic alloys under an extensive range of cooling rates with a view to analyzing the evolution of microstructure. It is shown that the microstructure is formed by a Zn-rich matrix of different morphologies and competitive eutectic mixtures (Zn-ZnMg and Zn-ZnMg). For 0.3 wt-pct Mg and 0.5 wt-pct Mg alloys, the Zn-rich matrix is shown to be characterized by high-cooling rates plate-like cells (cooling rates >9.5 and 24 K/s, respectively), followed by a granular–dendritic morphological transition for lower cooling rates. In contrast, a directionally solidified Zn1.2 wt-pct Mg alloy casting is shown to have the Zn-rich matrix formed only by dendritic equiaxed grains. Experimental growth laws are proposed relating the plate-like cellular interphase, the secondary dendritic arm spacing, and the eutectic interphase spacings to solidification thermal parameters, i.e., cooling rate and growth rate. The experimental law for the growth of secondary dendritic spacings under unsteady-state solidifications is also shown to encompass results of hypoeutectic Zn-Mg alloys subjected to steady-state Bridgman growth.The authors acknowledge the financial support provided by FAPESP-São Paulo Research Foundation, Brazil (Grants 2012/08494-0, 2013/15478-3, 2013/25452-1, 2013/23396-7, 2014/50502-5), CNPq-The Brazilian Research Council, and CSIC-Spanish National Research Council (Project i-link0944).Peer Reviewe