Citrinin as a possible cause of the pruritis, pyrexia, haemorrhagic syndrome in cattle

An outbreak of the pruritis, pyrexia, haemorrhagic syndrome affected eight of a herd of 175 cows which was divided into two groups of 115 and 60 according to yield. There was no difference in management between them but citrus pulp pellets were fed only to the larger group in which the eight cows were affected. Silage, which had been made without the use of additives, was also fed to both groups. The citrus pulp was visibly mouldy and contained 30 to 40 parts per billion of citrinin. Signs of the syndrome occurred within three days of the cows starting to ingest the citrus pulp, which was fed for 21 days, and the last case occurred six days after the feeding of citrus pulp ceased. Five calves whose dams had been fed citrus pulp were subsequently born with superior prognathism. In contrast to the eight cows that developed the syndrome only one out of 68 heifers which were fed larger quantities of citrus pulp for 10 days developed mild signs of the syndrome and then recovered, suggesting that older animals may be more susceptible. The clinical signs, gross pathology and histopathology are described and compared with those of previous outbreaks. Mycotoxins, particularly citrinin, were strongly implicated as the cause of this outbreak.     

Positive regulation of T cell activation and integrin adhesion by the adapter Fyb/Slap

The molecular adapter Fyb/Slap regulates signaling downstream of the T cell receptor (TCR), but whether it plays a positive or negative role is controversial. We demonstrate that Fyb/Slap-deficient T cells exhibit defective proliferation and cytokine production in response to TCR stimulation. Fyb/Slap is also required in vivo for T cell-dependent immune responses. Functionally, Fyb/Slap has no apparent role in the activation of known TCR signaling pathways, F-actin polymerization, or TCR clustering. Rather, Fyb/Slap regulates TCR-induced integrin clustering and adhesion. Thus, Fyb/Slap is the first molecular adapter to be identified that couples TCR stimulation to the avidity modulation of integrins governing T cell adhesion.     

Diverse juvenile life‐history behaviours contribute to the spawning stock of an anadromous fish population

Habitat quality often varies substantially across space and time, producing a shifting mosaic of growth and mortality trade‐offs across watersheds. Traditional studies of juvenile habitat use have emphasised the evolution of single optimal strategies that maximise recruitment to adulthood and eventual fitness. However, linking the distribution of individual behaviours that contribute to recruitment at the population level has been elusive, particularly for highly fecund aquatic organisms. We examined juvenile habitat use within a population of sockeye salmon (Oncorhynchus nerka) that spawn in a watershed consisting of two interconnected lakes and a marine lagoon. Otolith microchemical analysis revealed that the productive headwater lake accounted for about half of juvenile growth for those individuals surviving to spawn in a single river in the upper watershed. However, 47% of adults had achieved more than half of their juvenile growth in the downstream less productive lake, and 3% of individuals migrated to the estuarine environment during their first summer and returned to freshwater to overwinter before migrating back to sea. These results describe a diversity of viable habitat‐use strategies by juvenile sockeye salmon that may buffer the population against poor conditions in any single rearing environment, reduce density‐dependent mortality and have implications for the designation of critical habitat for conservation purposes. A network of accessible alternative habitats providing trade‐offs in growth and survival may be important for long‐term viability of populations.     

Body size distributions in North American freshwater fish: small‐scale factors and synthesis

The ecosystem size/trophic structure hypothesis predicts that the shape of body size distributions will change with ecosystem size because of increases in the relative importance of large, predatory, species. I test the hypothesis by examining the statistical moments, as measures of shape, of species body size distributions of North American freshwater fish assemblages in lakes. Species lists, coupled with dietary and body size information, are used to document the patterns. Body size distributions in small lakes are unimodal and right‐skewed, but distributions become more symmetrical and bimodal in large ecosystems. In small lakes, body sizes are generally small and fish trophic levels low, but size and trophic level increase up to lake volumes of about 0.001 km³, and change little in larger lakes. Adding trophic level to the analysis greatly improves the variance explained by the body size–lake size relation. The conclusions of Griffiths (2012, Global Ecology & Biogeography 21: 383‐392), that postglacial recolonisation and evolutionary change are important determinants of body size distributions at regional and larger scales, are combined with those of this study. Mean body size in local assemblages of lake‐dwelling species is larger than in regional and continental ones. Overall, body size distributions are affected by processes operating at a variety of spatial and temporal scales, with the type, size and duration of the ecosystem probably playing a central role by influencing the proportions of vagile and predatory species, the species which dominate the large size mode.     

Retarded growth rate and delayed onset of egg production associated with spirochaete infection in pullets

Retarded growth rates and delayed onset of egg production were recorded in 22-week-old pullets reared on deep litter and with indirect contact with pigs. Birds reared in cages or transferred to cages were unaffected. Spirochaetes were isolated and identified from the intestines of the pullets reared on deep litter but not from those reared in cages. Birds kept solely on deep litter were more severely affected, with 24 per cent immature birds and 10 per cent mortality compared with those transferred from deep litter to cages where no mortality was recorded but 15 to 22 per cent were found to be immature. The histopathological changes are described and the significance of the findings is discussed.     

Remotely sensed spatial dynamics of the Illex argentinus fishery, Southwest Atlantic

Illex argentinus, the Argentine short-finned squid, is an important species within the Patagonian shelf ecosystem, where it supports a major multi-national fishery. The fishing fleet operating in this region is comprised of jigging vessels which attract squid using powerful incandescent lights. These fishing lights are detectable in remotely sensed satellite imagery which makes the fishery unusually amenable to a large-scale analysis of its spatial dynamics. In this paper, long-term inter-annual variability in fleet distribution and extent is examined using imagery from the Defence Meteorological Satellite Program-Operational Linescan System (DMSP-OLS) for the period 1993–2005. The fishery was found to occupy a wide area across the shelf and slope, with regions of consistent fishing activity observed on the high seas (45–47°S) and to the north of the Falkland Islands (Malvinas). Distribution of the fishery over the 13-year study period was variable, with 28% of the fished area occupied in 1–2 years, and 7% of the area occupied in 12–13 years. Annual catch levels were positively associated with the extent of the area occupied by the fleet. Higher catches corresponded to the fishery occupying a wide latitudinal range, whereas lower catches were observed during 2004 and 2005 corresponding to a contraction of the fishery away from the south of its range. In years of very high catches, fishing took place along almost the entire latitudinal range of the species. Due to the intensity of fishing, changes in the distribution of the fleet can reflect shifts in the distribution of I. argentinus; this has potential for the long-term monitoring of this highly variable squid fishery.     

A comparison of cerebral arteriography and cavernous sinus venography in the dog

The technique and relative merits of cerebral arteriography and cavernous sinus venography are reviewed. Of seven cases investigated by cerebral arteriography, only one case showed evidence of abnormality and this was confirmed at post-mortem. Of nine cases investigated by cavernous sinus venography, six cases had positive findings, five of which have subsequently been substantiated pathologically.
Résumé. On passe en revue les techniques et les mérites relatifs de l'artériographie cérébrale et de la veinographie du sinus cavnereux. Sur 7 cas soumis à l'artériographie cérébrale, un seul a presénté des anomalies confirmées à l'autopsie. Sur les 9 cas dans lesquels on a utilisé la veinographie du sinus caverneux, 6 ont donné des résultats positifs et parmi eux, 5 ont reçu une confirmation anatomo-pathologique ultérieure.
Zusammenfassung. Die Methoden und relativen Vorzüge der cerebralen Artériographie und der cavernösen Sinusvenographie werden besprochen. Von den sieben mit cerebraler Artériographie untersuchten Fällen zeigte nur einer Anzeichen von Anomalität, die bei der Autopsie bestätigt wurde. Von neun Fällen, die mit cavernösen Sinusvenographie untersucht wurden, ergaben sechs positive Befunde, von denen fünf später pathologisch bestätigt wurden.