Suspended sediment pulse effects in rainbow trout (Oncorhynchus mykiss) - relating apical and systemic responses

To provide an integrated perspective on mineral particle effects in salmonids, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to daily mica particle pulses for 8 and 24 days. On day 8, increased immature erythrocyte proportions indicated a previous stress response. This response was absent on day 24, on which condition factor as well as plasma protein and aspartate aminotransferase activity decreased. The latter two related negatively to the hepato-somatic index, suggesting metabolic adaptations. The hepato-somatic index increased on days 8 and 24, while spleen-somatic index increased on day 24. No histopathological damage occurred in gills, liver, spleen, or kidney. However, splenic melano-macrophages increased on both days, and hyaline degenerations of kidney tubular cells were apparent on day 24. Overall, particle pulses affected rainbow trout more via turbidity rather than by physical damage. We conclude that (i) rainbow trout may adapt to sediment pulses as early as 8 days of exposure and (ii) particle pulses over 24 days can cause structural and metabolic changes in rainbow trout, even when gill damage is absent and apical effects on condition are moderate.

Characterization of a novel picornavirus isolate from a diseased European eel (Anguilla anguilla)

A novel picornavirus was isolated from specimens of a diseased European eel (Anguilla anguilla). This virus induced a cytopathic effect in eel embryonic kidney cells and high mortality in a controlled transmission study using elvers. Eel picornavirus has a genome of 7,496 nucleotides that encodes a polyprotein of 2,259 amino acids. It has a typical picornavirus genome layout, but its low similarity to known viral proteins suggests a novel species in the family Picornaviridae.

Prevalence and risk factors for carriage of multi-drug resistant Staphylococci in healthy cats and dogs

We investigated the distribution of commensal staphylococcal species and determined the prevalence of multi-drug resistance in healthy cats and dogs. Risk factors associated with the carriage of multi-drug resistant strains were explored. Isolates from 256 dogs and 277 cats were identified at the species level using matrix-assisted laser desorption ionisation-time of flight mass spectrometry. The diversity of coagulase-negative Staphylococci (CNS) was high, with 22 species in dogs and 24 in cats. Multi-drug resistance was frequent (17%) and not always associated with the presence of the mecA gene. A stay in a veterinary clinic in the last year was associated with an increased risk of colonisation by multi-drug resistant Staphylococci (OR = 2.4, 95% CI: 1.1˜5.2, p value LRT = 0.04). When identifying efficient control strategies against antibiotic resistance, the presence of mechanisms other than methicillin resistance and the possible role of CNS in the spread of resistance determinants should be considered.

Electroanatomic mapping of the endocardium. Implication for catheter ablation of ventricular tachycardia.

The electroanatomic mapping system Carto((R)) with its combination of anatomic and electrophysiologic information has substantially improved our understanding of arrhythmia mechanisms and substrates in patients with ventricular tachycardia (VT) and structural heart disease. Identification of the individual arrhythmogenic substrate and successful ablation guided by the combination of sinus rhythm voltage mapping and conventional electrophysiologic techniques like pace and activation/entrainment mapping are best described for patients with recurrent VT in remote myocardial infarction. In about 75-90% of the patients, the target VT can be ablated with acute success and the patients remain free of any VT recurrence in up to 75%. First results of electroanatomically guided ablation in patients with arrhythmogenic right ventricular dysplasia are promising. Data on ablation of VT in other structural heart diseases are very limited, since the arrhythmogenic substrate is very diffuse, e. g., in dilated cardiomyopathy, or there are only small patient numbers, e. g., for cardiac sarcoidosis or monomorphic VT after repair of congenital heart disease. In this article, the current status of electroanatomically guided endocardial mapping and ablation of VT in patients with structural heart disease is described.

Habitat selection of three cryptic Plecotus bat species in the European Alps reveals contrasting implications for conservation

Assessing the ecological requirements of species coexisting within a community is an essential requisite for developing sound conservation action. A particularly interesting question is what mechanisms govern the stable coexistence of cryptic species within a community, i.e. species that are almost impossible to distinguish. Resource partitioning theory predicts that cryptic species, like other sympatric taxa, will occupy distinct ecological niches. This prediction is widely inferred from eco-morphological studies. A new cryptic long-eared bat species, Plecotus macrobullaris, has been recently discovered in the complex of two other species present in the European Alps, with even evidence for a few mixed colonies. This discovery poses challenges to bat ecologists concerned with planning conservation measures beyond roost protection. We therefore tested whether foraging habitat segregation occurred among the three cryptic Plecotus bat species in Switzerland by radiotracking 24 breeding female bats (8 of each species). We compared habitat features at locations visited by a bat versus random locations within individual home ranges, applying mixed effects logistic regression. Distinct, species-specific habitat preferences were revealed. P. auritus foraged mostly within traditional orchards in roost vicinity, with a marked preference for habitat heterogeneity. P. austriacus foraged up to 4.7 km from the roost, selecting mostly fruit tree plantations, hedges and tree lines. P. macrobullaris preferred patchy deciduous and mixed forests with high vertical heterogeneity in a grassland dominated-matrix. These species-specific habitat preferences should inform future conservation programmes. They highlight the possible need of distinct conservation measures for species that look very much alike.

Delaying mowing and leaving uncut refuges boosts orthopterans in extensively managed meadows: Evidence drawn from field-scale experimentation

Semi-natural grasslands are widely recognized for their high ecological value. They often count among the most species-rich habitats, especially in traditional cultural landscapes. Maintaining and/or restoring them is a top priority, but nevertheless represents a real conservation challenge, especially regarding their invertebrate assemblages. The main goal of this study was to experimentally investigate the influence of four different mowing regimes on orthopteran communities and populations: (1) control meadow (C-meadow): mowing regime according to the Swiss regulations for extensively managed meadows declared as ecological compensation areas, i.e. first cut not before 15 June; (2) first cut not before 15 July (delayed treatment, D-meadow); (3) first cut not before 15 June and second cut not earlier than 8 weeks from the first cut (8W-meadow); (4) refuges left uncut on 10–20% of the meadow area (R-meadow). Data were collected two years after the introduction of these mowing treatments. Orthopteran densities from spring to early summer were five times higher in D-meadows, compared to C-meadows. In R-meadows, densities were, on average, twice as high as in C-meadows, while mean species richness was 23% higher in R-meadows than in C-meadows. Provided that farmers were given the appropriate financial incentives, the D- and R-meadow regimes could be relatively easy to implement within agri-environment schemes. Such meadows could deliver substantial benefits for functional biodiversity, including sustenance to many secondary consumers dependent on field invertebrates as staple food.

Landscape connectivity, habitat structure and activity of bat guilds in farmland-dominated matrices

Agricultural intensification has caused a decline in structural elements in European farmland, where natural habitats are increasingly fragmented. The loss of habitat structures has a detrimental effect on biodiversity and affects bat species that depend on vegetation structures for foraging and commuting. We investigated the impact of connectivity and configuration of structural landscape elements on flight activity, species richness and diversity of insectivorous bats and distinguished three bat guilds according to species-specific bioacoustic characteristics. We tested whether bats with shorter-range echolocation were more sensitive to habitat fragmentation than bats with longer-range echolocation. We expected to find different connectivity thresholds for the three guilds and hypothesized that bats prefer linear over patchy landscape elements. Bat activity was quantified using repeated acoustic monitoring in 225 locations at 15 study plots distributed across the Swiss Central Plateau, where connectivity and the shape of landscape elements were determined by spatial analysis (GIS). Spectrograms of bat calls were assigned to species with the software batit by means of image recognition and statistical classification algorithms. Bat activity was significantly higher around landscape elements compared to open control areas. Short- and long-range echolocating bats were more active in well-connected landscapes, but optimal connectivity levels differed between the guilds. Species richness increased significantly with connectivity, while species diversity did not (Shannon's diversity index). Total bat activity was unaffected by the shape of landscape elements. Synthesis and applications. This study highlights the importance of connectivity in farmland landscapes for bats, with shorter-range echolocating bats being particularly sensitive to habitat fragmentation. More structurally diverse landscape elements are likely to reduce population declines of bats and could improve conditions for other declining species, including birds. Activity was highest around optimal values of connectivity, which must be evaluated for the different guilds and spatially targeted for a region's habitat configuration. In a multi-species approach, we recommend the reintroduction of structural elements to increase habitat heterogeneity should become part of agri-environment schemes.