A canine vaccine against Leptospira serovars Icterohaemorrhagiae, Canicola and Grippotyphosa provides cross protection against Leptospira serovar Copenhageni.

Efficacy of the Leptospira components of multivalent vaccine DAPPi-L was previously demonstrated against virulent challenge with three serovars of Leptospira interrogans (Canicola, Icterohaemorrhagiae and Grippotyphosa) carried out 14 days after primary vaccination. In this study we demonstrate that this vaccine provides, two weeks after vaccination, an additional protection (prevention of mortality, clinical signs, renal infection, bacterial excretion, renal carriage and renal lesions) against fatal leptospirosis due to Leptospira interrogans serovar Copenhageni (serovar of major medical importance).

Compatibility between a rabies vaccine and a combined vaccine against canine distemper, adenovirosis, parvovirosis, parainfluenza virus and leptospirosis.

In many cicumstances, veterinarians are requiring to be able to administer rabies vaccine in dogs at the same time as vaccinating against canine distemper, adenovirus, parvovirus, parainfluenza virus and leptospirosis. The aim of this study was to assess the compatibility between a multivalent vaccine and a rabies vaccine when injected at two separate sites. Lack of interference was assessed by comparing serological response to viral components during one year following primary vaccination with vaccines administered alone or concomitantly. Antibody response to all tested components was comparable, irrespective of whether vaccines were administered individually or concurrently. Notably, the rabies vaccine induced very strong and protective seroconversion in dogs, whether it was administered concomitantly with the combo vaccine or not. This facilitates administration of rabies vaccine, which is a key factor for controlling the disease.

Modeling additive and non-additive effects in a hybrid population using genome-wide genotyping: prediction accuracy implications.

Hybrids are broadly used in plant breeding and accurate estimation of variance components is crucial for optimizing genetic gain. Genome-wide information may be used to explore models designed to assess the extent of additive and non-additive variance and test their prediction accuracy for the genomic selection. Ten linear mixed models, involving pedigree- and marker-based relationship matrices among parents, were developed to estimate additive (A), dominance (D) and epistatic (AA, AD and DD) effects. Five complementary models, involving the gametic phase to estimate marker-based relationships among hybrid progenies, were developed to assess the same effects. The models were compared using tree height and 3303 single-nucleotide polymorphism markers from 1130 cloned individuals obtained via controlled crosses of 13 Eucalyptus urophylla females with 9 Eucalyptus grandis males. Akaike information criterion (AIC), variance ratios, asymptotic correlation matrices of estimates, goodness-of-fit, prediction accuracy and mean square error (MSE) were used for the comparisons. The variance components and variance ratios differed according to the model. Models with a parent marker-based relationship matrix performed better than those that were pedigree-based, that is, an absence of singularities, lower AIC, higher goodness-of-fit and accuracy and smaller MSE. However, AD and DD variances were estimated with high s.es. Using the same criteria, progeny gametic phase-based models performed better in fitting the observations and predicting genetic values. However, DD variance could not be separated from the dominance variance and null estimates were obtained for AA and AD effects. This study highlighted the advantages of progeny models using genome-wide information.

Precocious sexual signalling and mating in Anastrepha fraterculus (Diptera: Tephritidae) sterile males achieved through juvenile hormone treatment and protein supplements.

Sexual maturation of Anastrepha fraterculus is a long process. Methoprene (a mimic of juvenile hormone) considerably reduces the time for sexual maturation in males. However, in other Anastrepha species, this effect depends on protein intake at the adult stage. Here, we evaluated the mating competitiveness of sterile laboratory males and females that were treated with methoprene (either the pupal or adult stage) and were kept under different regimes of adult food, which varied in the protein source and the sugar:protein ratio. Experiments were carried out under semi-natural conditions, where laboratory flies competed over copulations with sexually mature wild flies. Sterile, methoprene-treated males that reached sexual maturity earlier (six days old), displayed the same lekking behaviour, attractiveness to females and mating competitiveness as mature wild males. This effect depended on protein intake. Diets containing sugar and hydrolyzed yeast allowed sterile males to compete with wild males (even at a low concentration of protein), while brewer´s yeast failed to do so even at a higher concentration. Sugar only fed males were unable to achieve significant numbers of copulations. Methoprene did not increase the readiness to mate of six-day-old sterile females. Long pre-copulatory periods create an additional cost to the management of fruit fly pests through the sterile insect technique (SIT). Our findings suggest that methoprene treatment will increase SIT effectiveness against A. fraterculus when coupled with a diet fortified with protein. Additionally, methoprene acts as a physiological sexing method, allowing the release of mature males and immature females and hence increasing SIT efficiency.

Past climate changes explain the phylogeography of Vitellaria paradoxa over Africa.

The evolution of the savanna biome has been deeply marked by repeated contraction/expansion phases due to climate perturbations during the Quaternary period. In this study, we investigated the impact of the last glacial maximum (LGM) on the present genetic pattern of Vitellaria paradoxa (shea tree), a major African savanna tree. A range-wide sampling of the species enabled us to sample 374 individuals from 71 populations distributed throughout sub-Sahelian Africa. Trees were genotyped using 3 chloroplasts and 12 nuclear microsatellites, and were sequenced for 2 polymorphic chloroplast intergenic spacers. Analyses of genetic diversity and structure were based on frequency-based and Bayesian methods. Potential distributions of V. paradoxa at present, during the LGM and the last interglacial period, were examined using DIVA-GIS ecological niche modelling (ENM). Haplotypic and allelic richness varied significantly across the range according to chloroplast and nuclear microsatellites, which pointed to higher diversity in West Africa. A high but contrasted level of differentiation was revealed among populations with a clear phylogeographic signal, with both nuclear (F(ST) = 0.21; R(ST) = 0.28; R(ST) > R(ST) (permuted)) and chloroplast simple sequence repeats (SSRs) (G(ST) = 0.81; N(ST) = 0.90; N(ST) > N(ST) (permuted)). We identified a strong geographically related structure separating western and eastern populations, and a substructure in the eastern part of the area consistent with subspecies distinction. Using ENM, we deduced that perturbations during the LGM fragmented the potential eastern distribution of shea tree, but not its distribution in West Africa. Our main results suggest that climate variations are the major factor explaining the genetic pattern of V. paradoxa.

Long-distance seed and pollen dispersal inferred from spatial genetic structure in the very low-density rainforest tree, Baillonella toxisperma Pierre, in Central Africa.

We analysed the spatial distribution of genetic diversity to infer gene flow for Baillonella toxisperma Pierre (Moabi), a threatened entomophilous pollinated and animal-dispersed Central African tree, with typically low density (5-7 adults trees/km(2)). Fifteen nuclear and three universal chloroplast microsatellites markers were used to type 247 individuals localized in three contiguous areas with differing past logging intensity. These three areas were within a natural forest block of approximately 2886 km(2) in Gabon. Expected heterozygosity and chloroplast diversity were He(nuc) = 0.570 and H(cp) = 0.761, respectively. F(IS) was only significant in one area (F(IS) = 0.076, P < 0.01) and could be attributed to selfing. For nuclear loci, Bayesian clustering did not detect discrete gene pools within and between the three areas and global differentiation (F(STnuc) = 0.007, P > 0.05) was not significant, suggesting that they are one population. At the level of the whole forest, both nuclear and chloroplast markers revealed a weak correlation between genetic relatedness and spatial distance between individuals: Sp(nuc) = 0.003 and Sp(cp) = 0.015, respectively. The extent of gene flow (σ) was partitioned into global gene flow (σ(g)) from 6.6 to 9.9 km, seed dispersal (σ(s)) from 4.0 to 6.3 km and pollen dispersal (σ(p)) from 9.8 to 10.8 km. These uncommonly high dispersal distances indicate that low-density canopy trees in African rainforests could be connected by extensive gene flow, although, given the current threats facing many seed disperser species in Central Africa, this may no longer be the case.

Small effect of fragmentation on the genetic diversity of Dalbergia monticola, an endangered tree species of the eastern forest of Madagascar, detected by chloroplast and nuclear microsatellites.

BACKGROUND AND AIMS: The oriental forest ecosystem in Madagascar has been seriously impacted by fragmentation. The pattern of genetic diversity was analysed on a tree species, Dalbergia monticola, which plays an important economic role in Madagascar and is one of the many endangered tree species in the eastern forest. METHODS: Leaves from 546 individuals belonging to 18 small populations affected by different levels of fragmentation were genotyped using eight nuclear (nuc) and three chloroplast (cp) microsatellite markers. KEY RESULTS: For nuclear microsatellites, allelic richness (R) and heterozygosity (H(e,nuc)) differed between types of forest: R = 7.36 and R = 9.55, H(e,nuc) = 0.64 and H(e,nuc) = 0.80 in fragmented and non-fragmented forest, respectively, but the differences were not significant. Only the mean number of alleles (N(a,nuc)) and the fixation index F(IS) differed significantly: N(a,nuc) = 9.41 and N(a,nuc) = 13.18, F(IS) = 0.06 and F(IS) = 0.15 in fragmented and non-fragmented forests, respectively. For chloroplast microsatellites, estimated genetic diversity was higher in non-fragmented forest, but the difference was not significant. No recent bottleneck effect was detected for either population. Overall differentiation was low for nuclear microsatellites (F(ST,nuc) = 0.08) and moderate for chloroplast microsatellites (F(ST,cp) = 0.49). A clear relationship was observed between genetic and geographic distance (r = 0.42 P < 0.01 and r = 0.42 P = 0.03 for nuclear and chloroplast microsatellites, respectively), suggesting a pattern of isolation by distance. Analysis of population structure using the neighbor-joining method or Bayesian models separated southern populations from central and northern populations with nuclear microsatellites, and grouped the population according to regions with chloroplast microsatellites, but did not separate the fragmented populations. CONCLUSIONS: Residual diversity and genetic structure of populations of D. monticola in Madagascar suggest a limited impact of fragmentation on molecular genetic parameters.

Comparison of antibody responses after vaccination with two inactivated rabies vaccines.

Thirty laboratory dogs were randomly assigned to two groups (A and B) of 15 dogs and subcutaneously vaccinated with a single dose of one of two commercially available monovalent inactivated rabies vaccines: RABISIN (Merial, France) (group A) and NOBIVAC Rabies (Intervet International) (group B). Rabies antibodies were measured over a period of 4 months using the fluorescent antibody virus neutralization (FAVN) test. The two vaccines performed differently in terms of magnitude and persistence of rabies antibodies titers in dogs. Two weeks after vaccination, average rabies antibody titers peaked at 2.53 IU/mL (range, 0.17-13.77 IU/mL) and 1.26 IU/mL (range, 0.50-4.56 IU/mL) in groups A and B dogs, respectively. The average FAVN antibody titres against rabies on D28, D56, D84, D112 and D120 were significantly higher in group A than in group B. Although all dogs from group B serologically responded to vaccination, the proportion of dogs with antibody titres >or=0.5 IU/mL dropped significantly after D28 and was statistically significantly lower on D56, D84 and D112 compared to group A dogs. In conclusion, in the context of international trade, the choice of the vaccine and the timing of blood tests are critical factors in achieving successful serological test results after rabies vaccination. RABISIN induces high and sustained antibody titres against rabies, increasing the flexibility for the time of blood sampling after primo-vaccination.

Genetic diversity and gene flow in a Caribbean tree Pterocarpus officinalis Jacq.: a study based on chloroplast and nuclear microsatellites.

We analysed the molecular diversity of Pterocarpus officinalis, a tree species distributed in Caribbean islands, South and Central America to quantify the genetic variation within island, to assess the pattern of differentiation and infer levels of gene flow; with the overall goal of defining a strategy of conservation. Two hundred two individuals of 9 populations were analysed using three chloroplast and six nuclear microsatellite markers. The observed heterozygosity varied markedly among the populations for nuclear (H(Onuc )= 0.20-0.50) and chloroplast microsatellites (H (cp )= 0.22-0.68). The continental population from French Guyana showed a higher value of H(Onuc) than island populations, and the differences were significant in some cases. The fixation index F (IS) ranged from -0.043 to 0.368; a significant heterozygote deficit was detected in 7 populations. The heterozygosity excess method suggested that two populations in Guadeloupe have undergone a recent bottleneck. Global and pairwise F (ST) were high for both nuclear (F(STnuc )= 0.29) and chloroplast microsatellites (F(STcp )= 0.58). The neighbour-joining tree based on both markers, presented a differentiation pattern that can be explained by the seed dispersal by flotation and marine stream. The comparison of Bayesian approach and the method based on allelic frequency demonstrate a very limited number of migrants between populations.

Isolation and characterization of 15 nuclear microsatellite markers for Baillonella toxisperma Pierre (Sapotaceae), a low-density tree species of Central Africa.

Baillonella toxisperma is a scattered endemic species of the Guineo-Congolian forest. We developed 15 nuclear microsatellite markers specifically for B. toxisperma to analyse the genetic diversity of 188 individuals distributed in two natural populations in Gabon. On average, 8.3 alleles per locus were identified; observed heterozygosity ranged from 0.056 to 0.872 and expected heterozygosity from 0.282 to 0.823 among populations. Only three loci showed a significant departure to Hardy-Weinberg equilibrium, but no linkage disequilibrium was observed for any pair of loci.

Isolation and characterization of microsatellite markers for Casearia sylvestris Sw. (Salicaceae), a neotropical medicinal tree.

Casearia sylvestris Sw. is a widespread neotropical tree utilized in popular medicine. Recent research ranked Casearia as one of the most promising genus in the search of drugs against cancer. Despite its wide distribution and pharmacological importance, no microsatellite markers have yet been developed for this genus. In this study, we provide 10 polymorphic microsatellite loci specifically designed for C. sylvestris, used to analyse 90 individuals distributed in two populations from São Paulo state, Brazil. On average, 12.3 alleles per locus were identified, showing the ability of the markers to detect microsatellite polymorphism in this species.

Arbuscular mycorrhizal colonization and nodulation improve flooding tolerance in Pterocarpus officinalis Jacq. seedlings.

Pterocarpus officinalis (Jacq.) seedlings inoculated with the arbuscular mycorrhizal fungus, Glomus intraradices, and the strain of Bradyrhizobium sp. (UAG 11A) were grown under stem-flooded or nonflooded conditions for 13 weeks after 4 weeks of nonflooded pretreatment under greenhouse conditions. Flooding of P. officinalis seedlings induced several morphological and physiological adaptive mechanisms, including formation of hypertrophied lenticels and aerenchyma tissue and production of adventitious roots on submerged portions of the stem. Flooding also resulted in an increase in collar diameter and leaf, stem, root, and total dry weights, regardless of inoculation. Under flooding, arbuscular mycorrhizas were well developed on root systems and adventitious roots compared with inoculated root systems under nonflooding condition. Arbuscular mycorrhizas made noteworthy contributions to the flood tolerance of P. officinalis seedlings by improving plant growth and P acquisition in leaves. We report in this study the novel occurrence of nodules connected vascularly to the stem and nodule and arbuscular mycorrhizas on adventitious roots of P. officinalis seedlings. Root nodules appeared more efficient fixing N(2) than stem nodules were. Beneficial effect of nodulation in terms of total dry weight and N acquisition in leaves was particularly noted in seedlings growing under flooding conditions. There was no additive effect of arbuscular mycorrhizas and nodulation on plant growth and nutrition in either flooding treatment. The results suggest that the development of adventitious roots, aerenchyma tissue, and hypertrophied lenticels may play a major role in flooded tolerance of P. officinalis symbiosis by increasing oxygen diffusion to the submerged part of the stem and root zone, and therefore contribute to plant growth and nutrition.

Comparison of quantitative and molecular variation in agroforestry populations of the shea tree (Vitellaria paradoxa C.F. Gaertn) in Mali.

In this study we investigated the within- and between-population genetic variation using microsatellite markers and quantitative traits of the shea tree, Vitellaria paradoxa, an important agroforestry tree species of the Sudano-Sahelian region in Africa. Eleven populations were sampled across Mali and in northern Côte d'Ivoire. Leaf size and form and growth traits were measured in a progeny test at the nursery stage. Eight microsatellites were used to assess neutral genetic variation. Low levels of heterozygosity were recorded (1.6-3.0 alleles/locus; H(E) = 0.25-0.42) and the fixation index (F(IS) = -0.227-0.186) was not significantly different from zero suggesting that Hardy-Weinberg equilibrium is encountered in all populations sampled. Quantitative traits exhibited a strong genetic variation between populations and between families within populations. The degree of population differentiation of the quantitative traits (Q(ST) = 0.055-0.283, Q(STmean) = 0.189) strongly exceeds that in eight microsatellite loci (F(ST) = -0.011-0.142, F(STmean) = 0.047). Global and pairwise F(ST) values were very low and not significantly different from zero suggesting agroforestry practices are amplifying gene flow (Nm = 5.07). The population means for quantitative traits and the rainfall variable were not correlated, showing variation was not linked with this climatic cline. It is suggested that this marked differentiation for quantitative traits, independent of environmental clines and despite a high gene flow, is a result of local adaptation and human selection of shea trees. This process has induced high linkage disequilibrium between underlying loci of polygenic characters.

Genetic diversity and population structure of an insular tree, Santalum austrocaledonicum in New Caledonian archipelago.

We present a study of the genetic diversity and structure of a tropical tree in an insular system. Santalum austrocaledonicum is endemic to the archipelago of New Caledonia and is exploited for oil extraction from heartwood. A total of 431 individuals over 17 populations were analysed for eight polymorphic microsatellite loci. The number of alleles per locus ranged from 3 to 33 and the observed heterozygosity per population ranged from 0.01 in Mare to 0.74 in Ile des Pins. The genetic diversity was lowest in the most recent islands, the Loyautes, and highest in the oldest island, Grande Terre, as well as the nearby small Ile des Pins. Significant departures from panmixia were observed for some loci-population combinations (per population FIS = 0-0.03 on Grande-Terre and Ile des Pins, and 0-0.67 on Loyautes). A strong genetic differentiation among all islands was observed (FST = 0.22), and the amount of differentiation increased with geographic distance in Iles Loyaute and in Grande Terre. At both population and island levels, island age and isolation seem to be the main factors influencing the amount of genetic diversity. In particular, populations from recent islands had large average FIS that could not be entirely explained by null alleles or a Wahlund effect. This result suggests that, at least in some populations, selfing occurred extensively. Conclusively, our results indicate a strong influence of insularity on the genetic diversity and structure of Santalum austrocaledonicum.

Silent antibodies.

Over the past years, progress has been made in understanding B cells and antibody recognition functions, particularly in the context of autoimmune diseases. In addition to the existence of "natural antibodies", recent studies suggest the existence of immunoglobulins with no apparent specificity that may acquire polyreactivity following a mild denaturation in inflammatory sites. They are called "silent antibodies". Together with related observations on B cell development, selection and signaling, the recent insights are providing clues into our understanding of autoimmunity.

Genetic diversity of the shea tree (Vitellaria paradoxa C.F. Gaertn), detected by RAPD and chloroplast microsatellite markers.

RAPDs and chloroplast microsatellites were used to quantify the genetic variation of Vitellaria paradoxa (an economically important tree species in sub-Saharan Africa, north of the equator) and to analyse the geographic distribution of diversity in relation to the refuge theory. A total of 13 locations were sampled in eight countries, covering most of the natural range from Senegal to Uganda. A total of 67 polymorphic and 15 monomorphic RAPD loci were detected in 179 individuals. No relationship was identified between diversity and longitude or latitude. An unrooted neighbour-joining tree suggested a western group and an eastern group, representing 7% (P = 0.000) of the total variation. A Mantel test suggested that genetic distances between populations were correlated to geographic distances (R = 0.88, P = 0.001). The three-chloroplast microsatellite primers, assayed in 116 individuals, revealed 10 different alleles and seven chlorotypes. Most of the populations comprised a single haplotype. It is proposed from these results that the difference between western and eastern populations results from putative refugia separated by the current 'Dahomey Gap' (a semiarid zone that meets the coast around the Ghana-Togo-Benin-Nigeria borders), an area that may have been exceptionally dry during glacial periods. In addition, it is suggested that the haplotype distribution and frequency in the western populations could be due to the more recent impact of humans, particularly shea tree selection and dispersal during traditional agroforestry.

Induction of a mucosal immune response to the streptococcal M protein by intramuscular administration of a PADRE-ASREAK peptide.

In a previous study, it was shown that an intramuscular administration of amino acid PADRE-ELDKWA sequence induced a mucosal immune response to a conserved epitope of human immunodeficiency virus in mice. In the same model, here it is shown that this method can be used with a selected peptide from the M protein of group A streptococci. The PADRE-ASREAK sequence was injected in mice by the intramuscular route. Antibodies against M protein were detected in extracts of mucosal tissues and in serum. The repertoire isotypes of serum immunoglobulin G (IgG) and mucosal IgA and IgG antibodies varied, according to the dose of injected peptide. The highest mucosal IgA antibody response was obtained with 0.01 micro g of antigen per injection, whereas the systemic IgG antibody response increased with 10 micro g of antigen. Mucosal antibody production against streptococci was confirmed by immunofluorescence analysis. These results provide evidence that this novel approach of mucosal vaccination may be of advantage for bacterial systems and suggest a new field of investigation based on synthetic peptide analogues.

Fibre remote optoelectronic gamma dosimetry based on optically stimulated luminescence of Al2O3:C.

Optically stimulated luminescence dosimetry (OSL-D) used in conjunction with fibre optics enables a remote measurement of dose, for the purpose of radioprotection in the nuclear industry and in medicine (radiology, radiotherapy). Alumina OSL crystals are used because of their low Z, low fading and optical transparency, which improves the sensitivity. An optoelectronic portable dosemeter has been designed and tested that shows a dose detection of 50 microGy with a 20 metre-long fibre. Following irradiation, all trapped electrons are released under light stimulation while the OSL is integrated to provide dose-equivalent measurements. A compensation technique is designed with the help of the MCNP4b code, so that both angular and photon energy characteristics comply with international standards (CEI 61066) for photon dose equivalent Hp(10). Two sensors are described that allow measurements over a wide solid angle (95% of 4piSr), for photon energies ranging from 15 keV to 3 MeV.

Prevalence of verotoxin-producing Escherichia coli (VTEC) in slurry, farmyard manure and sewage sludge in France.

AIMS: The aims of the present study were to determine VTEC prevalence in manure, slurry and sewage sludge in France and to characterize the VTEC strains isolated (virulence genes and serotype). METHODS AND RESULTS: Seven hundred and fifty-two samples from 55 farmyard manures, 136 bovine and porcine faeces, 114 slurries, 10 composts, and 437 samples from outflows of sewage wastewater treatment plants were analysed. Twenty-four percent contained isolates which were PCR positive for stx gene. Twenty-one VTEC strains were recovered from positive samples by colony hybridization: 76% of them were positive for stx(2) gene, 33% for stx(1) gene,and 19% for eae gene. One strain belonged to serotype O157:H7 and two others to serogroups O26 and O55, respectively. CONCLUSIONS: Some of the VTEC strains isolated from environments in France should be considered as potentially pathogenic for humans. SIGNIFICANCE AND IMPACT OF THE STUDY: Appropriate handling or use of manure, slurry and sewage sludge is necessary so that contamination of the environment and food by VTEC can be prevented.

Mucosal immunity induced by intramuscular administration of free peptides in-line with PADRE: IgA antibodies to the ELDKWA epitope of HIV gp41.

To improve the mucosal antibody response against a short amino acid (aa) sequence (ELDKWA) of HIV gp41, we have investigated a construction including this peptide in-line with the Pan DR epitope (PADRE). ELDKWA is a conserved peptide playing a key role in the pathogenicity of HIV transmission. PADRE is a non-natural peptide with multipotential immunogenic properties. The results show striking differences between mucosal and systemic immune systems, with a preferential response of the mucosal organs. In contrast with most mucosal immunizations, the intracellular response persists for over two months after the last injection. This strongly suggests that further investigations of conserved key epitopes from various pathogens may lead to safe and chemically defined mucosal vaccines with synthetic peptides. These candidate vaccines with free peptides may be suitable for mass campaigns even in developing countries.