SPINAL SUB ARACHNOID CYSTS IN 13 DOGS

Thirteen dogs, including 6 Rottweiler dogs, exhibiting clinical signs of spinal cord dysfunction and myelographically confirmed subarachnoid space enlargement were investigated. To characterize the lesions and to get a better understanding of their pathogenesis, different imaging techniques were used in association with explorative surgical procedures (12 dogs) and histopathologic techniques (5 dogs). All subjects underwent preoperative myelography, five of which were examined by computed tomography (CT) scanning and one by magnetic resonance imaging (MRI) as well as cerebrospinal fluid (CSF) flow measurement (velocimetry). Most animals were <12 months old (7/13 dogs) and Rottweilers were over-represented (6/13 dogs). The lesions were mainly located dorsally with respect to the spinal cord (10/13 dogs) and in the cranial cervical area (8/13 dogs). MRI suggested spinal cord deviation with signs of ventral leptomeningeal adhesion opposite the enlarged space. In one dog, velocimetry confirmed that the "cyst" was freely communicating with the surrounding CSF space. Surgical investigation confirmed leptomeninges-induced ventral adhesion in 4/5 dogs. Follow-up studies, carried out from 6 months to 2.5 years postoperatively, showed there was full recovery in 8/13 dogs. This study suggests that the compression of the spinal cord is possibly not caused by a cyst. Adhesion resulting from a combination of microtrauma and chronic inflammatory processes induces a secondary enlargement of the subarachnoid space and may be a significant causative factor in spinal cord compression and dysfunction. The over-representation of Rottweilers and the young age of the animals in the study suggest a possible genetic predisposition and an inherited etiology.     

Temporal shifts in landscape connectivity for an ecosystem engineer,the roe deer,across a multiple-use landscape

Context

Routine movements of large herbivores, often considered as ecosystem engineers, impact key ecological processes. Functional landscape connectivity for such species influences the spatial distribution of associated ecological services and disservices.

Objectives

We studied how spatio-temporal variation in the risk-resource trade-off, generated by fluctuations in human activities and environmental conditions, influences the routine movements of roe deer across a heterogeneous landscape, generating shifts in functional connectivity at daily and seasonal time scales.

Methods

We used GPS locations of 172 adult roe deer and step selection functions to infer landscape connectivity. In particular, we assessed the influence of six habitat features on fine scale movements across four biological seasons and three daily periods, based on variations in the risk-resource trade-off.

Results

The influence of habitat features on roe deer movements was strongly dependent on proximity to refuge habitat, i.e. woodlands. Roe deer confined their movements to safe habitats during daytime and during the hunting season, when human activity is high. However, they exploited exposed open habitats more freely during night-time. Consequently, we observed marked temporal shifts in landscape connectivity, which was highest at night in summer and lowest during daytime in autumn. In particular, the onset of the autumn hunting season induced an abrupt decrease in landscape connectivity.

Conclusions

Human disturbance had a strong impact on roe deer movements, generating pronounced spatio-temporal variation in landscape connectivity. However, high connectivity at night across all seasons implies that Europe’s most abundant and widespread large herbivore potentially plays a key role in transporting ticks, seeds and nutrients among habitats.

     

Nutritional implications of feeding free-living birds in public urban areas

Supplementary feeding can affect populations of birds. It reduces energy spent on foraging and reduces the risk of starvation, but it also increases the risk of disease transmission and predation. Supplementary feeding may reduce species richness if some species are better able to exploit supplementary food resources than others. Feeding may also artificially inflate the carrying capacity of the ecosystem, leading to bird nuisance in the form of droppings and noise. The aim of this study was to characterise and quantify the risk factors and consequences of feeding free-living birds in public areas in the western part of the city of Amsterdam. In seven study areas, the following data were collected: bird population size and species composition, feeding events, and the type and amount of supplementary food offered. Estimations were made of the nutritional energy provided and the number of birds that could be supported by the food offered. Members of the public who fed the birds were invited to complete a questionnaire on various aspects of feeding. Results showed that supplementary feeding attracts juvenile gulls and feral pigeons, which could in the long-term affect biodiversity. Bread was the main category of supplementary food being offered (estimated to be 67% of the total amount of food). The majority of respondents fed birds so as not to waste bread and meal leftovers. In six of the seven areas studied, an overabundance of nutritional energy was calculated. We conclude that the current type and extent of supplementary feeding in the city of Amsterdam is nutritionally unbalanced and affects species diversity at a local level. The overabundance is undesirable for reasons of both animal health, because it can lead to malnutrition, and public health, because surplus food attracts rats and may also have a negative effect on water quality.     

Deep Subseafloor Fungi as an Untapped Reservoir of Amphipathic Antimicrobial Compounds

The evolving global threat of antimicrobial resistance requires a deep renewal of the antibiotic arsenal including the isolation and characterization of new drugs. Underexplored marine ecosystems may represent an untapped reservoir of novel bioactive molecules. Deep-sea fungi isolated from a record-depth sediment core of almost 2000 m below the seafloor were investigated for antimicrobial activities. This antimicrobial screening, using 16 microbial targets, revealed 33% of filamentous fungi synthesizing bioactive compounds with activities against pathogenic bacteria and fungi. Interestingly, occurrence of antimicrobial producing isolates was well correlated with the complexity of the habitat (in term of microbial richness), as higher antimicrobial activities were obtained at specific layers of the sediment core. It clearly highlights complex deep-sea habitats as chemical battlefields where synthesis of numerous bioactive compounds appears critical for microbial competition. The six most promising deep subseafloor fungal isolates were selected for the production and extraction of bioactive compounds. Depending on the fungal isolates, antimicrobial compounds were only biosynthesized in semi-liquid or solid-state conditions as no antimicrobial activities were ever detected using liquid fermentation. An exception was made for one fungal isolate, and the extraction procedure designed to extract amphipathic compounds was successful and highlighted the amphiphilic profile of the bioactive metabolites.     

Distribution and organoleptic impact of sotolon enantiomers in dry white wines

The enantiomers of sotolon, a flavor compound typical of oxidized white wines, were separated by preparative HPLC to determine their perception thresholds and distribution in wines. The enantiomeric ratios of chiral sotolon were evaluated in several dry white wines using gas chromatography and a chiral column (beta-cyclodextrin) connected to a 2 m precolumn (BP20). The perception threshold of (S)-sotolon (0.8 microg/L) in model wine solution was 100 times lower than that of the (R) form (89 microg/L), indicating that (S)-sotolon contributes to the characteristic aroma of prematurely aged dry white wines. Both enantiomers are detected in white wines. Analysis of commercial dry white wines from various vintages and origins revealed three types of distribution patterns: the racemic form, an excess of R, and an excess of S. The proportions found in these wines may be partially explained by the slow racemization kinetics (20 months) of optically active sotolon.