Study on the Coffea arabica/Colletotrichum kahawae pathosystem: Impact of a biological plant protection product

Journal of Plant Diseases and Protection - Coffee berry disease (Colletotrichum kahawae) causes fruits rots on Arabica coffee leading to harvest losses of around 40%. Using biological molecules may...     

An African horse sickness virus serotype 4 recombinant canarypox virus vaccine elicits specific cell-mediated immune responses in horses

A recombinant canarypox virus vectored vaccine co-expressing synthetic genes encoding outer capsid proteins, VP2 and VP5, of African horse sickness virus (AHSV) serotype 4 (ALVAC(?)-AHSV4) has been demonstrated to fully protect horses against homologous challenge with virulent field virus. Guthrie et al. (2009) detected weak and variable titres of neutralizing antibody (ranging from <10 to 40) 8 weeks after vaccination leading us to hypothesize that there could be a participation of cell mediated immunity (CMI) in protection against AHSV4. The present study aimed at characterizing the CMI induced by the experimental ALVAC(?)-AHSV4 vaccine. Six horses received two vaccinations twenty-eight days apart and three horses remained unvaccinated. The detection of VP2/VP5 specific IFN-γ responses was assessed by enzyme linked immune spot (ELISpot) assay and clearly demonstrated that all ALVAC(?)-AHSV4 vaccinated horses developed significant IFN-γ production compared to unvaccinated horses. More detailed immune responses obtained by flow cytometry demonstrated that ALVAC(?)-AHSV4 vaccinations induced immune cells, mainly CD8(+) T cells, able to recognize multiple T-epitopes through all VP2 and only the N-terminus sequence of VP5. Neither VP2 nor VP5 specific IFN-γ responses were detected in unvaccinated horses. Overall, our data demonstrated that an experimental recombinant canarypox based vaccine induced significant CMI specific for both VP2 and VP5 proteins of AHSV4.     

A Bayesian zero-truncated approach for analysing capture-recapture count data from classical scrapie surveillance in France

Capture-recapture (CR) methods are used to study populations that are monitored with imperfect observation processes. They have recently been applied to the monitoring of animal diseases to evaluate the number of infected units that remain undetected by the surveillance system. This paper proposes three bayesian models to estimate the total number of scrapie-infected holdings in France from CR count data obtained from the French classical scrapie surveillance programme. We fitted two zero-truncated Poisson (ZTP) models (with and without holding size as a covariate) and a zero-truncated negative binomial (ZTNB) model to the 2006 national surveillance count dataset. We detected a large amount of heterogeneity in the count data, making the use of the simple ZTP model inappropriate. However, including holding size as a covariate did not bring any significant improvement over the simple ZTP model. The ZTNB model proved to be the best model, giving an estimation of 535 (CI(95%) 401-796) infected and detectable sheep holdings in 2006, although only 141 were effectively detected, resulting in a holding-level prevalence of 4.4‰ (CI(95%) 3.2-6.3) and a sensitivity of holding-level surveillance of 26% (CI(95%) 18-35). The main limitation of the present study was the small amount of data collected during the surveillance programme. It was therefore not possible to build complex models that would allow depicting more accurately the epidemiological and detection processes that generate the surveillance data. We discuss the perspectives of capture-recapture count models in the context of animal disease surveillance.     

Bound ferulic acid from bran is more bioavailable than the free compound in rat

Ferulic acid (FA) is reported as a good antioxidant absorbed by human or rat but only few data deal with the influence of the food matrix on its bioavailability and with its potential protection against cardiovascular diseases and cancer. Wheat bran is used as a source of ferulic acid, the compound being mainly bound to arabinoxylans of the plant cell walls. Pharmacokinetic profiles of FA and its metabolites are established in rats. Free and conjugated FA quickly appear in plasma, reach a plateau 1 h after intake and remain approximately constant at 1 microM up to 24 h. 2.3% of FA are eliminated in urine. Compared with results obtained after intake of free FA, the presence of FA-arabinoxylans bonds in the food matrix increases the occurrence time of FA in the organism and decreases the level of urinary excretion in 24 h. Nevertheless, sulfated FA is still the main plasmatic form. The antioxidant activity of plasmas of rats fed with a standard diet (containing no FA), pure ferulic acid (5.15 mg FA/kg bw) or bran (4.04 mg FA/kg bw) are measured in an ex vivo test using AAPH as free radical inducer. Plasmas of rats fed with bran show a better antioxidant activity than the control group and the pure FA supplemented group, increasing the resistance of erythrocytes to hemolysis by factors of 2 and 1.5, respectively. These results show the good bioavailability of FA from bran and its potential efficiency to protect organism against pathology involving radical steps of development.     

THE ENGINEER AND CIVILIZATION

To sum up the whole matter, the engineer, either as an individual or as a collective type, is simply a link in the chain of human progress-a chain the links of which, in one form or another, run back into a past removed from our own time by tens of thousands of years, to go to no higher figures. With the trend of human progress as it now is, he seems, moreover, to be a very necessary link. He has taken upon himself the peculiar function of developing and translating into use for the needs of civilization the constructive materials of the earth and the inorganic energies of nature, and in connection with the exercise of such function he has acquired peculiar and weighty duties and responsibilities.     

Mechanisms of Nitrate Transfer from Soil to Stream in an Agricultural Watershed of French Brittany

In French Brittany, water pollution with nitrate due tointensive agriculture has become one of the major environmentalconcerns. In this article, the nitrate, sulfate and chlorideconcentrations from the groundwater and the stream of a first-order agricultural watershed, are analyzed to infer the mechanisms responsible for the distribution and transfer of nitrate within the watershed. The aquifer is constituted by three layers: the thin soil cover, the weathered shale and thefissured shale. The weathered shale groundwater appears to bea large reservoir of nitrate in the watershed. Indeed the amount of nitrate is estimated at about 450 kg N ha^-1, 5 to 9 times the total annual nitrate flux in the stream. In the upslope zones, this groundwater exhibited high nitrate concentrations (up to 138.4±10.5 mg NO₃ ^- L^-1), which decreased along the flow paths towards the stream (77.1±13.8 mg NO₃ ^- L^-1). Unlike nitrate, sulfate concentrations showed an increase from uphillto downhill (from 6.1±0.8 to 12.5±5.4 mg SO₄ ^2- L^-1) with little change in chloride concentrations. These patterns are presumed to result from upward flows from fissured shale groundwater where denitrification by oxidation of pyrite occurs with sulfate as end product. A scheme of nitrate transfer is proposed where stream discharge would result from the mixing of three end members which are: uphill weathered groundwater, deep groundwater and water in the uppermost soil horizons ofthe bottomlands. Temporal variability of nitrate concentrationsin base flow reflects changes in the relative contribution of each end member.     

Efficient profile-likelihood confidence intervals for capture-recapture models

In a capture-recapture analysis, uncertainty in the parameter estimates is usually expressed by presenting classical Wald-type confidence intervals. This approach involves (1) the assumption that the maximum likelihood estimates are asymptotically normal and (2) numerical computation of the variance-covariance matrix of these estimates. When the sample size is small or when the estimates are on the boundary of their domain, a Wald confidence interval often performs badly. A natural alternative is to use profile-likelihood confidence intervals. In general, these intervals require a greater amount of computation. We propose a new implementation of this approach that is efficient, both in reducing the amount of computation and in coping with boundary estimates. We also show how profile-likelihood confidence intervals can be adjusted for overdispersion. Simulations were used to check whether nominal coverage levels were attained, and allowed us to compare this approach with the classical Wald procedure. We illustrate this work by considering a multi-state model for a sooty shearwater (Puffinus griseus) population.