Serum antibody responses in Creole kids experimentally infected with Haemonchus contortus

The objective of this study was to evaluate the relationship of parasite-specific serum antibodies with the resistance status of Creole kids. The average breeding values on egg output predicted in a context of natural infection at 11 months of age were distant of 1.07 genetic standard deviation between resistant and susceptible animals. After drenching the animals were maintained worm-free during 1 month until experimental infection with 10,000 Haemonchus contortus infective larvae (L3). Enzyme-linked immunosorbent assay was carried out in serum samples to determine the level of IgG, IgA and IgE anti-H. contortus L3 crude extracts and adult excretion/secretion products (ESP). Parasitological and blood immunological parameters were measured on the 2 extreme groups. Despite the absence of any typical signs of haemonchosis, susceptible kids had more than 11 times higher faecal egg counts (FEC) at 35 days post-infection (d.p.i.) than resistant kids had. Levels of immunoglobulin against H. contortus L3 and ESP increased significantly after infection in both groups. However, no difference in the host immune response mediated by immunoglobulin against H. contortus was evidenced between groups. This finding suggests that, in goats previously infected by H. contortus, a degree of protection occurred and the phenotypic and genetic segregation in resistant and susceptible animals were not related to the humoral immune response. The correlation coefficients between FEC and IgE anti-ESP (r=0.593; P<0.05 was significant in both resistant and susceptible animals. Such correlation suggesting a hypersensitivity reaction dependent on worm prolificacy has never been described. This result needs further studies to understand the mechanisms underlying this observation.     

Synthesis: Platforms for collective action in multiple-use common-pool resources

In this special issue, Steins and Edwards introduced the notion of nested platforms for resource use negotiation as a tool to facilitate collective action amongst multiple-users in complex common-pool resource management scenarios. Five discussion statements were put forward to aid the debate on multi-use platforms. This paper is a synthesis of the responses to these statements by the other contributors to this special issue. It aims to further stimulate the debate on the management of complex, multiple-use common-pool management scenarios.     

Impact of Co-Culture on the Metabolism of Marine Microorganisms

Natural products from plants have been listed for hundreds of years as a source of biologically active molecules. In recent years, the marine environment has demonstrated its ability to provide new structural entities. More than 70% of our planet’s surface is covered by oceans, and with the technical advances in diving and remotely operated vehicles, it is becoming easier to collect samples. Although the risk of rediscovery is significant, the discovery of silent gene clusters and innovative analytical techniques has renewed interest in natural product research. Different strategies have been proposed to activate these silent genes, including co-culture, or mixed fermentation, a cultivation-based approach. This review highlights the potential of co-culture of marine microorganisms to induce the production of new metabolites as well as to increase the yields of respective target metabolites with pharmacological potential, and moreover to indirectly improve the biological activity of a crude extract.     

Whole body barometric plethysmography: a screening method to investigate airway reactivity and acute lung injuries in freely moving pigs

The aim of this work was to investigate whether the Penh index, measured using whole body barometric plethysmography, can be used as a screening parameter to evaluate the airway reactivity and the intensity of the pulmonary response to endotoxins. Penh was firstly recorded in non-sedated freely moving piglets exposed (1) to a nebulized acetylcholine (Ach) pre-treated or not with clenbuterol, or (2) to endotoxin challenge. To measure Penh simultaneously with total pulmonary resistance (R(L)), dynamic compliance (C(dyn)) and intrapleural pressure changes (Max Delta Ppl), an oesophageal balloon catheter technique was used and the piglets were anaesthetised. The recordings were performed during (1) an intravenous metacholine (Mch) challenge and (2) in endotoxin-exposed animals. In freely moving animals, Ach induced a significant dose-dependent increase in Penh, which was significantly blocked by clenbuterol. Endotoxin instillation also resulted in a significant rise in Penh while the corresponding response measured under anaesthesia was significantly and positively correlated with R(L) and Max Delta Ppl. Similar results were obtained during Mch challenge but the Penh was negatively correlated with C(dyn). We conclude that Penh could be used in freely moving piglets as a screening index for airway reactivity and pulmonary functional changes in cholinergic and endotoxin challenges.     

A 10‐g Laboratory Wet‐Milling Procedure for Maize and Comparison With Larger Scale Laboratory Procedures

A very small scale laboratory procedure (≈10 g) is needed to test wet‐milling characteristics of corn when amounts of corn available for testing are quite limited. The objective of this study was to downscale 100‐g laboratory wet‐milling methods already widely used to measure wet‐milling properties of 10 g of corn. A Standard 100‐g procedure, a Modified 100‐g procedure, and an Experimental 10‐g procedure were compared using three corn hybrids with known differences in wet‐milling properties. All three procedures ranked most fraction yields (all except for germ) of the three hybrids the same. Germ separation was conducted differently for each procedure and probably accounts for these differences. Flotation and screening methods were likely affected by germ density and germ size, and hand‐picking the germ was efficient in recovering a pure germ fraction. The two 100‐g procedures were performed very similarly except for fiber recovery. The Modified 100‐g procedure was more efficient in recovering fiber because of intensive washing. Hybrid effects on the starch/gluten separation were more pronounced when the Experimental 10‐g procedure was used, which may allow for more discrimination among hybrids. Although most fraction yields are too small to run replicates for analytical tests, the Experimental 10‐g procedure will be useful in measuring milling efficiency of early generations of corn hybrids where limited samples are available, such as when valuable recombinant proteins are expressed for therapeutics and industrial enzymes.     

Usefulness of single copy genes containing introns in Phytophthora for the development of detection tools for the regulated species P. ramorum and P. fragariae

Introns are generally highly polymorphic regions within genes and were proven to be of great interest for discriminating among phylogenetically-close Phytophthora species. Phytophthora ramorum and P. fragariae are considered as quarantine pathogens by the European Union and accurate detection tools are therefore necessary for their monitoring. From introns located in different single copy genes (GPA1, RAS-like, and TRP1), we developed a series of PCR primers specific to P. ramorum and P. fragariae. The specificity of these primers was successfully checked with a wide collection of Phytophthora isolates and a protocol was developed to detect both pathogens directly in infected plant tissues. These genes should be of particular interest for the development of additional species-specific detection tools within the Phytophthora genus.     

Disturbances in European beech water relation during an extreme drought

Context

In the context of a probable increase in intensity and frequency of extreme summer drought events, a better understanding of the key processes involved in water relations is needed to improve the theoretical foundations of predictive process-based models.

Aims

This paper aims to analyse how temperate deciduous trees cope with water shortage.

Methods

The exceptional summer drought of 2003 in Europe provided an opportunity to monitor stomatal conductance and twig water potential in European beech (Fagus sylvatica L.) at predawn and midday and to analyse variations with respect to leaf height within the canopy. By comparing our field measurements of twig water potential to values found in the literature, we confirmed the strong impact of soil water shortage on crown water relations.

Results

This paper shows that (1) the vertical gradient of stomatal conductance within the crown disappeared under extreme soil water depletion; (2) at maximum drought intensity, predawn twig water potential (ψ _pd) reached ?2.3 MPa at a height of 14 m in the crown and ?2.0 MPa at a height of 10 m. The significant differences in ψ _pd between the two measurement heights in the canopy may be due to night transpiration; (3) there was a close relationship between predawn twig water potential and relative extractable soil water; (4) as drought conditions intensified, there was a close relationship between canopy radiation interception and predawn water potential, as estimated daily from relative extractable soil water.     

Radial distribution of carbohydrate reserves in the trunk of declining European beech trees (Fagus sylvatica L.)

Context

European beech (Fagus sylvatica L.) is considered threatened by anticipated climate change, but the physiological causes of potential beech decline or mortality remains poorly understood.

Aims

The purpose of the present study was to fuel debate about the assumption that carbohydrate depletion is involved in the decline of mature European beech.

Methods

The health status of beech trees from a severely declining stand was visually assessed by examining their crown condition. Content and radial distribution of non-structural carbohydrates (starch and soluble carbohydrate) were analyzed in the trunks and compared to those reported earlier in trunks of healthy beech trees.

Results and discussion

The distribution of carbohydrate in the beech trunks recorded here seemed affected by decline. We found a stronger radial decrease of starch content than those reported earlier for healthy beech trees. Carbohydrate reserves appear partially maintained in the outermost rings while starch depletion occurred in older wood rings in declining trees that may be able to mobilize carbohydrate reserves from older wood rings in response to successive climatic constraints.