Experimental concurrent infection of sheep with Oestrus ovis and Trichostrongylus colubriformis: effects of antiparasitic treatments on interactions between parasite populations and blood eosinophilic responses

The purpose of this experiment was to determine if an earlier infection with Oestrus ovis would down regulate an infection with Trichostrongylus colubriformis when the larvae of O. ovis were expelled from the nasal cavities of sheep by a specific treatment. Three groups of five lambs were used: group 1 was artificially infected with O. ovis larvae and later with T. colubriformis, group 2 received O. ovis larvae and later was treated with ivermectin 14 days before being infected with T. colubriformis. Group 3 was infected with T. colubriformis only. The criteria examined were: the effects on nematode egg excretion, worm fecundity, nematode burdens and the kinetics of blood eosinophils. Significant decreases of nematode egg excretion, worm fecundity, nematode burdens were observed in group 1 compared to group 3. However, no changes were observed in either group 2 or 3. In group 2 it was noted that antiparasitic treatment induced a rapid decrease in blood eosinophils to a range close to the non-infected control group and this was associated with the removal of the down regulation effects of nematode burdens. This experiment showed that there is no cross immunity between O. ovis and T. colubriformis and that eosinophils may act against any parasite without specific priming.     

Genetic basis for GPI-anchor merozoite surface antigen polymorphism of Babesia and resulting antigenic diversity

Glycosyl-phosphatidylinositol anchor merozoite surface antigens (GPI-anchor MSA) are proposed to act in the invasion process of infective merozoites of Babesia into host erythrocytes. Because of their essential function in the survival of Babesia parasites, they constitute good candidates for the development of vaccines against babesiosis and they have been extensively analyzed. These include Babesia bovis variable MSA (VMSA) and Babesia bigemina gp45/gp55 proteins of the agents of bovine babesiosis from tropical and subtropical countries, and the Babesia divergens Bd37 and Babesia canis Bc28 proteins of the main agents of bovine and canine babesiosis in Europe, respectively. However, these are very polymorphic antigens and Babesia parasites have evolved molecular mechanisms that enable these antigens to evade the host immune system as a survival strategy. This review focuses on the genetic basis of GPI-anchor MSA polymorphism and the antigenic diversity of B-cell epitopes that might be generated in each of these Babesia species. The picture is incomplete and no Babesia genome sequence is yet available. However, the available sequences suggest that two distinct, non cross-reactive GPI-anchor MSA (i.e., with unique B-cell epitopes) may be required by all Babesia species for invasion, and that these two distinct GPI-anchor MSA would be encoded by a multigene family. Furthermore, the data are consistent with the ability of biological clones from Babesia to use these multigene families for the expression of GPI-anchor MSA, either conserved (B. canis and B. bovis) or polymorphic (B. divergens and B. bigemina) in their amino acid sequence. Moreover, as a consequence for successful parasitism, the data suggest that both conserved and polymorphic GPI-anchor MSA would present unique B-cell epitopes.     

Chemically induced fast solid-state transitions of omega-VOPO4 in vanadium phosphate catalysts

Vanadium phosphates are important catalysts for the oxidation of alkanes, and commercial catalysts comprise a complex range of V4+ and V5+ phosphates. We used three complementary in situ characterization methodologies-powder x-ray diffraction and laser Raman and electron paramagnetic resonance spectroscopies-to show that the metastable phase omega-VOPO4 is very sensitive to many of the reactants and products of butane oxidation. A rapid transformation from omega-VOPO4 to delta-VOPO4 occurs on exposure to butane at the reaction temperature, and hence the metastable omega-VOPO4 may play a role in the formation of commercial catalysts.     

Educational variations in the consumption of foods containing fat in Finland and the Baltic countries

OBJECTIVE: To examine educational differences among people who consume foods containing fat in Finland and the Baltic countries. DESIGN: Data were collected from cross-sectional postal Finbalt Health Monitor surveys that were carried out in 1998, 2000 and 2002. SETTING: Estonia, Finland, Latvia and Lithuania. SUBJECTS: For each survey, nationally representative random samples of adults aged 20-64 years were drawn from population registers (Estonia, n = 3656; Finland, n = 9354, Latvia, n = 6015; Lithuania, n = 5944). RESULTS: Differences were revealed between the countries in the consumption of foods that contain fat. Finnish people consumed butter on bread, high-fat milk, meat and meat products, and vegetable oil for cooking less frequently than people in the Baltic countries. Cheese was most popular in Finland. Educational differences in fat-related food habits were examined by applying logistic regression analysis. A positive association was found between level of education and consumption of vegetable oil used in food preparation. Drinking high-fat milk was associated with low education in all countries. People with higher education tended to consume cheese more often. Educational patterns in the consumption of butter on bread and in the consumption of meat and meat products differed between countries. CONCLUSIONS: The consumption of foods containing fat was related to educational levels in all four countries. The diet of better-educated people was closer to recommendations for the consumption of saturated and unsaturated fats than the diet of people with lower level of education. The educational gradient was more consistent in Finland than in the Baltic countries. These existing educational differences in sources of fat consumed should be taken into account in the development of national cardiovascular disease prevention programmes.     

The successional status of tropical rainforest tree species is associated with differences in leaf carbon isotope discrimination and functional traits

We characterised the among species variability in leaf gas exchange and morphological traits under controlled conditions of seedlings of 22 tropical rainforest canopy species to understand the origin of the variability in leaf carbon isotope discrimination (Δ) among species with different growth and dynamic characteristics (successional gradient). Our results first suggest that these species pursue a consistent strategy in terms of Δ throughout their ontogeny (juveniles grown here versus canopy adult trees from the natural forest). Second, leaf Δ was negatively correlated with WUE and N, and positively correlated with g_s, but among species differences in Δ were mainly explained by differences in WUE. Finally, species belonging to different successional groups display distinct leaf functional and morphological traits. We confirmed that fast growing early successional species maximise carbon assimilation with high stomatal conductance. In contrast, fast and slow growing late successional species are both characterised by low carbon assimilation values, but by distinct stomatal conductance and leaf morphological features. Along the successional gradient, these differences result in much lower Δ for the intermediate species (i.e. fast growing late successional) as compared to the two other groups.     

Microbial biomass and N transformations in two soils cropped with annual and perennial species

A field study was undertaken to determine the effects of different plant species on soil microbial biomass and N transformations in a well drained silty clay loam (Typic Dystrochrept) and a poorly drained clay loam (Typic Humaquept). The crop treatments were faba bean (Vicia faba L.), alfalfa (Medicago sativa L.), timothy (Phleum pratense L.), bromegrass (Bromus inermis L.), reed canarygrass (Phalaris arundinacea L.), and wheat (Triticum aestivum L.). Measurements of microbial biomass C, denitrification capacity, and nitrification capacity were performed periodically in the top 2–10 cm of soil. On most sampling dates, all three parameters were higher under perennial than under annual species. The nitrification capacity was positively affected by the level of N applied to each species (r=0.65^** for the silty clay loam and 0.84^*** for the clay loam) and not directly by the plant. The differences found in microbial biomass C were significantly correlated with the water-soluble organic C present under each plant species (r=0.74^*** for the silty clay loam and 0.90^*** for the clay loam), suggesting differences in C deposition in the soil among plant species. In the silty clay loam, the denitrification capacity was positively related to the amount of organic C found under each plant species, while in the clay loam, it was dependent on the amount of N applied to each species. There was less denitrification activity per unit biomass under legume species than under graminease, suggesting that, depending on their composition, root-derived materials may be used differently by soil microbes.     

Biomonitoring of Trace Elements in Air and Soil Compartments Along the Major Motorway in France

The impact on the environment of Cd, Pb and Zn emissions from the A1 motorway, one of the busiest in France, was based on a simultaneous analysis of lichens, fungi and soil.The study was conducted in 12 rest areas located along a 55 kmstretch of the motorway. Cd, Pb and Zn concentrations in the top soil horizon (0–10 cm) largely exceeded their concentrations at the control site.The Cd-, Pb- and Zn levels in fruiting bodies of fungi Armillaria mellea, Coprinus comatus, Marasmius oreades and Paxillus involutus were highly variable between sites. The contamination degree of transplanted thalliof Parmelia caperata was well correlated to the cumulated traffic on the western side. On the eastern side, heavy metals originated from the traffic but also from neighbouring sources (urbanization and agricultural practices). Although lead levels are decreasing, leaded petrol is still on offer and lead remains an indicator of vehicle pollution.     

Freshwater protected areas: an effective measure to reconcile conservation and exploitation of the threatened European eels (Anguilla anguilla)?

Abstract – For decades, the European eel Anguilla anguilla (L.) population has been declining strongly despite several management attempts, so additional experiments need to be conducted on management measures. The use of freshwater protected areas has been advocated but their efficiency has never been assessed. In this study, we investigated whether the population structure and the silver eel (mature migrating stage) production differ in fished and protected areas within a marsh wetland (Brière, 7000 ha, Northwest France), using an intensive biological study (electrofishing and trapping) and a survey of the traditional fishery (licenses, questionnaires and creel surveys). First, we found that fishermen mainly targeted >320‐mm yellow eels (sedentary stage) using pots and square dipping nets and that harvest by fishermen was highly variable at different locations in the study area. Secondly, we found differences in the size‐class structures and mortality rates between protected and fished areas. Mortality rates of eels >320 mm was positively correlated with harvest by fishermen. Furthermore, the proportion of potentially migrating eels in the total population was found to be higher in the protected areas than in fished areas (6.38% vs. 1.42%, respectively). Thirdly, we found that protected areas potentially produce 8.4% of the total silver eel production whereas they only account for 2.4% of the aquatic habitat area. We estimated that a size adjustment of protected areas to 31.1% with maintaining the current fishery would produce 50% of the potential silver eel of a fully protected marsh. Protection of freshwater areas appears to be a promising management measure and a constructive consensual way to integrate the patrimonial and societal value of the traditional fishery and the international management plans for European eels. Furthermore, freshwater protective measures can be an effective local solution if they are integrated into the framework of freshwater biodiversity management and accompanied by other management measures that focus on all eel life stages.     

Legumes symbioses: absence of Nod genes in photosynthetic bradyrhizobia

Leguminous plants (such as peas and soybeans) and rhizobial soil bacteria are symbiotic partners that communicate through molecular signaling pathways, resulting in the formation of nodules on legume roots and occasionally stems that house nitrogen-fixing bacteria. Nodule formation has been assumed to be exclusively initiated by the binding of bacterial, host-specific lipochito-oligosaccharidic Nod factors, encoded by the nodABC genes, to kinase-like receptors of the plant. Here we show by complete genome sequencing of two symbiotic, photosynthetic, Bradyrhizobium strains, BTAi1 and ORS278, that canonical nodABC genes and typical lipochito-oligosaccharidic Nod factors are not required for symbiosis in some legumes. Mutational analyses indicated that these unique rhizobia use an alternative pathway to initiate symbioses, where a purine derivative may play a key role in triggering nodule formation.     

Bonnes pratiques de l’utilisation des dermocorticoïdes en dermatologie canine

The authors make recommendations for the optimal use of topical glucocorticoids in routine practice based on their experience in canine dermatology and evidence from the literature. The rationale behind the use of topical glucocorticoids is reminded, as are the main factors to consider in the selection of the appropriate product from current therapeutic armamentarium, taking into account notably the anti-inflammatory power and side effects of glucocorticoid compounds, their percutenous penetration and absorption, as well as available veterinary presentations. The specific circumstances and instructions for use of topical glucocorticoids are developed in each of their main indications (atopic dermatitis, flea allergy dermatitis, pyotraumatic dermatitis, contact dermatitis, auto-immune dermatitis, perianal fistulas), as are reminded the limits to their use and potential side effects, underlining the need for proper education of the owner and good therapeutic monitoring of the patient.Download : Download Acrobat PDF file (17MB)English Version. English Version