Blood and cloacal swab sampling for avian influenza monitoring has no effect on survival rates of free‐ranging ducks

Concerns about the spread of avian influenza viruses (AIVs) have led to cloacal swab sampling of hundreds of thousands of birds worldwide as part of AIV surveillance schemes, but the effects of cloacal swabbing have not been adequately evaluated. We tested for differences between swabbed, swabbed and bled, and non‐sampled wild ducks in terms of live re‐encounter and dead recoveries for Common Pochard Aythya ferina and Tufted Duck Aythya fuligula, and also determined re‐encounter and recovery rates for Mallard Anas platyrhynchos and Common Teal Anas crecca. No effects of sampling methods were detected, except in Teal. Re‐encounter rates were lower in sampled Teal than in controls, with annual re‐encounter probabilities being 25% and 35% lower in males and females, respectively. Teal possibly left or avoided sampling sites, or sought sites where they were less detectable after sampling. In general, no deleterious effects were found, suggesting that cloacal swabbing and blood sampling are suitable methods for conducting AIV surveillance in ducks.     

ΔRR vaccination protects from KA-induced seizures and neuronal loss through ICP10PK-mediated modulation of the neuronal-microglial axis

Ischemic brain injury and epilepsy are common neurodegenerative diseases caused by excitotoxicity. Their pathogenesis includes microglial production of inflammatory cytokines. Our studies were designed to examine whether a growth compromised HSV-2 mutant (ΔRR) prevents excitotoxic injury through modulation of microglial responses by the anti-apoptotic HSV-2 protein ICP10PK. EOC2 and EOC20 microglial cells, which are differentially activated, were infected with ΔRR or the ICP10PK deleted virus (ΔPK) and examined for virus-induced neuroprotective activity. Both cell lines were non-permissive for virus growth, but expressed ICP10PK (ΔRR) or the PK deleted ICP10 protein p95 (ΔPK). Conditioned medium (CM) from ΔRR-, but not ΔPK-infected cells prevented N-methyl-D-aspartate (NMDA)-induced apoptosis of primary hippocampal cultures, as determined by TUNEL and caspase-3 activation (76.9 ± 5.3% neuroprotection). Neuroprotection was associated with inhibition of TNF-α and RANTES and production of IL-10. The CM from ΔPK-infected EOC2 and EOC20 cells did not contain IL-10, but it contained TNF-α and RANTES. IL-10 neutralization significantly (p < 0.01) decreased, but did not abrogate, the neuroprotective activity of the CM from ΔRR-infected microglial cultures indicating that ICP10PK modulates the neuronal-microglial axis, also through induction of various microglial neuroprotective factors. Rats given ΔRR (but not ΔPK) by intranasal inoculation were protected from kainic acid (KA)-induced seizures and neuronal loss in the CA1 hippocampal fields. Protection was associated with a significant (p < 0.001) increase in the numbers of IL-10+ microglia (CD11b+) as compared to ΔPK-treated animals. ΔRR is a promising vaccination/therapy platform for neurodegeneration through its pro-survival functions in neurons as well as microglia modulation.     

Isoflavonoid exudation from white lupin roots is influenced by phosphate supply, root type and cluster-root stage

The internal concentration of isoflavonoids in white lupin (Lupinus albus) cluster roots and the exudation of isoflavonoids by these roots were investigated with respect to the effects of phosphorus (P) supply, root type and cluster-root developmental stage.To identify and quantify the major isoflavonoids exuded by white lupin roots, we used high-pressure liquid chromatography (HPLC) coupled to electrospray ionization (ESI) in mass spectrometry (MS).The major exuded isoflavonoids were identified as genistein and hydroxygenistein and their corresponding mono- and diglucoside conjugates. Exudation of isoflavonoids during the incubation period used was higher in P-deficient than in P-sufficient plants and higher in cluster roots than in noncluster roots. The peak of exudation occurred in juvenile and immature cluster roots, while exudation decreased in mature cluster roots.Cluster-root exudation activity was characterized by a burst of isoflavonoids at the stage preceding the peak of organic acid exudation. The potential involvement of ATP-citrate lyase in controlling citrate and isoflavonoid exudation is discussed, as well as the possible impact of phenolics in repelling rhizosphere microbial citrate consumers.     

B cell receptors and complement receptors target the antigen to distinct intracellular compartments

The processing of exogenous Ags is an essential step for the generation of immunogenic peptides that will be presented to T cells. This processing relies on the efficient intracellular targeting of Ags, because it depends on the content of the compartments in which Ags are delivered in APCs. Opsonization of Ags by the complement component C3 strongly enhances their presentation by B cells and increases their immunogenicity in vivo. To investigate the role of C3 in the targeting of Ags, we compared the intracellular traffic of proteins internalized by complement receptor (CR) and B cell receptor (BCR) in B lymphocytes. Whereas both receptors are able to induce efficient Ag presentation, their intracellular pathways are different. CR ligand is delivered to compartments containing MHC class II molecules (MHC-II) but devoid of transferrin receptor and Lamp-2, whereas BCR rapidly targets its ligand toward Lamp-2-positive, late endosomal MHC-II-enriched compartments through intracellular vesicles containing transferrin receptor. CR and BCR are delivered to distinct endocytic pathways, and the kinetic evolution of the protein content of these pathways is very different. Both types of compartments contain MHC-II, but CR-targeted compartments receive less neosynthesized MHC-II than do BCR-targeted compartments. The targeting induced by CR toward compartments that are distinct from BCR-targeted compartments probably participates in C3 modulation of Ag presentation.     

A molecular and karyological approach to the taxonomy of Nautilus

Nautiloids, the externally shelled cephalopods of Cambrian origin, are the most ancient lineage among extant cephalopods. Their ancestral characters are explored based on morphological and molecular data (18S rDNA sequence) to investigate the evolution of present cephalopod lineages. Among molluscs, nautilus 18S rDNA gene is the longest reported so far, due to large nucleotidic insertions. By comparison with other 18S sequences, the complete gene of N. macromphalus helps to clarify the taxonomic status of the three universally recognised Nautilus species. The range of interspecific molecular differences supports separation of the present species into two surviving ectocochleate genera, Nautilus and Allonautilus. Nautiloid 18S is considered as corresponding to the ancestral form of 18S as is the number of chromosomes in Nautilus (52), the lowest among cephalopods. Comparison of karyological characteristics amongst cephalopods in a phylogenetic context suggests a possible correlation between duplication events and lineage divergence.     

Functional and structural basis of carnitine palmitoyltransferase 1A deficiency

Carnitine palmitoyltransferase 1A (CPT1A) is the key regulatory enzyme of hepatic long-chain fatty acid beta-oxidation. Human CPT1A deficiency is characterized by recurrent attacks of hypoketotic hypoglycemia. We presently analyzed at both the functional and structural levels five missense mutations identified in three CPT1A-deficient patients, namely A275T, A414V, Y498C, G709E, and G710E. Heterologous expression in Saccharomyces cerevisiae permitted to validate them as disease-causing mutations. To gain further insights into their deleterious effects, we localized these mutated residues into a three-dimensional structure model of the human CPT1A created from the crystal structure of the mouse carnitine acetyltransferase. This study demonstrated for the first time that disease-causing CPT1A mutations can be divided into two categories depending on whether they affect directly (functional determinant) or indirectly the active site of the enzyme (structural determinant). Mutations A275T, A414V, and Y498C, which exhibit decreased catalytic efficiency, clearly belong to the second class. They are located more than 20 A away from the active site and mostly affect the stability of the protein itself and/or of the enzyme-substrate complex. By contrast, mutations G709E and G710E, which abolish CPT1A activity, belong to the first category. They affect Gly residues that are essential not only for the structure of the hydrophobic core in the catalytic site, but also for the chain-length specificity of CPT isoforms. This study provides novel insights into the functionality of CPT1A that may contribute to the design of drugs for the treatment of lipid disorders.