Assessing evidence of a potential Salmonella transmission across the poultry food chain

Enhanced Salmonella surveillance programmes in poultry were implemented in all European Member States, with minimum prevalence targets for a list of targeted serotypes to safeguard food and public health. Based on the Belgian Salmonella surveillance programme and focusing on poultry, the overarching aim of this study was to highlight possible Salmonella transmissions across the food chain (FC). For this purpose, firstly, the prevalence patterns of Salmonella (targeted and the most prevalent non-targeted) serotypes along the FC were described over time. Secondly, the effectiveness of the control measures against vertical transmission (breeders to 1-day-old broiler and layer chicks) was indirectly assessed by looking into the odds of targeted serotypes detection. Thirdly, it was appraised if Salmonella prevalence can significantly increase during broilers and layers production. In addition, it was tested if being tested negative at the end of production in broilers when tested positive at the entrance is serotype dependent (targeted vs. non-targeted serotypes). Results showed that, firstly, the prevalence patterns of the listed serotypes were inconstant over time and across the FC. Secondly, the odds of Salmonella targeted serotype detection in 1-day-old broiler and in 1-day-old layer flocks were lower than in breeder flocks while, thirdly, infection during broiler and layer production can lead to significant increase in positivity in subsequent samples. Finally, being infected by a targeted or by non-targeted serotype at the entrance of the flock poorly reflects the Salmonella status at the end of production. Note that this study did not make a distinction between the different sources of contamination and the effects of sampling methods and isolation methods should be subject to further investigation.     

Effect of extractives on vibrational properties of African Padauk (<Emphasis Type="Italic">Pterocarpus soyauxii</Emphasis> Taub.)

Extractives can affect the vibrational properties tanδ (damping coefficient) and E′/ρ (specific Young’s modulus), but this is highly dependent on species, compounds, and cellular locations. This paper investigates such effects for African Padauk (Pterocarpus soyauxii Taub.), a tropical hardwood with high extractives content and a preferred material for xylophones. Five groups of 26 heartwood specimens with large, yet comparable, ranges in vibrational properties were extracted in different solvents. Changes in vibrational properties were set against yields of extracts and evaluation of their cellular location. Methanol (ME) reached most of the compounds (13%), located about half in lumen and half in cell-wall. Water solubility was extremely low. tanδ and E′/ρ were very strongly related (R ² ≥ 0.93), but native wood had abnormally low values of tanδ, while extraction shifted this relation towards higher tanδ values. ME extracted heartwood became in agreement with the average of many species, and close to sapwood. Extractions increased tanδ as much as 60%, irrespective of minute moisture changes or initial properties. Apparent E′/ρ was barely changed (+2% to −4%) but, after correcting the mass contribution of extracts, it was in fact slightly reduced (down to −10% for high E′/ρ), and increasingly so for specimens with low initial values of E′/ρ.     

Reforestation of burned stands: The effect of ectomycorrhizal fungi on Pinus pinaster establishment

The area occupied by Pinus pinaster in Portugal is rapidly diminishing because of forest fires. Ectomycorrhizal fungi form obligate, mutually beneficial associations with P. pinaster which improve plant growth and resistance to adverse conditions. The aim of this work was to assess whether native ectomycorrhizal fungi could be a useful tool in the reforestation of burned areas. The work was conducted in a forest nursery greenhouse, where P. pinaster seedlings were inoculated with compatible ectomycorrhizal fungal isolates: Suillus bovinus, Pisolithus tinctorius, Rhizopogon roseolus, and a mixture of the three fungi, using burned and unburned forest soil as substrate. Inoculation significantly enhanced the growth of P. pinaster, with R. roseolus proving to be the most effective in burned soil, with an 8-fold increase in plant fresh weight. Overall, inoculation stimulated growth most in burned than in unburned soil.This study suggests that inoculation with selected ectomycorrhizal fungi in containerised nurseries can be an advantageous approach for the successful establishment of P. pinaster in burned soil. The obtained results point out to the interest of extending these studies into fire-impacted areas, using ectomycorrhizal fungi as a biological tool.     

Heterogeneous atmospheric aerosol production by acid-catalyzed particle-phase reactions

According to evidence from our laboratory, acidic surfaces on atmospheric aerosols lead to potentially multifold increases in secondary organic aerosol (SOA) mass. Experimental observations using a multichannel flow reactor, Teflon (polytetrafluoroethylene) film bag batch reactors, and outdoor Teflon-film smog chambers strongly confirm that inorganic acids, such as sulfuric acid, catalyze particle-phase heterogeneous reactions of atmospheric organic carbonyl species. The net result is a large increase in SOA mass and stabilized organic layers as particles age. If acid-catalyzed heterogeneous reactions of SOA products are included in current models, the predicted SOA formation will be much greater and could have a much larger impact on climate forcing effects than we now predict.     

No major schizophrenia locus detected on chromosome 1q in a large multicenter sample

Reports of substantial evidence for genetic linkage of schizophrenia to chromosome 1q were evaluated by genotyping 16 DNA markers across 107 centimorgans of this chromosome in a multicenter sample of 779 informative schizophrenia pedigrees. No significant evidence was observed for such linkage, nor for heterogeneity in allele sharing among the eight individual samples. Separate analyses of European-origin families, recessive models of inheritance, and families with larger numbers of affected cases also failed to produce significant evidence for linkage. If schizophrenia susceptibility genes are present on chromosome 1q, their population-wide genetic effects are likely to be small.     

Combining permanent aerobiological networks and molecular analyses for large-scale surveillance of forest fungal pathogens: A proof-of-concept

Forest disease management relies principally on a preventive approach in which epidemiological surveillance plays a crucial role. However, efficient and cost-effective surveillance methods are not currently available for large spatial scales. Nevertheless, aerobiological networks have been set up for several decades in many countries to monitor pollen dispersal and provide real-time assessments of allergenic risk. Here, we suggest that the same approach could be used for the surveillance of forest pathogens. Using molecular methods, we analysed samples from 12 sites of the French aerobiological network, at different dates. Both metabarcoding by high-throughput sequencing (using two markers and two different bioinformatics approaches) and real-time PCR targeting eight important forest pathogens were conducted. To validate the approach, temporal and spatial trends of spore detection were compared with field disease data. The metabarcoding approach demonstrated that many fungal plant pathogens could be found in aerobiological samples. Moreover, five of the eight targeted forest pathogens were detected by real-time PCR, with temporal and spatial trends of spore capture consistent with field data. In particular, Hymenoscyphus fraxineus was detected at high frequency in aerobiological samples in the areas where ash dieback has been present for the longest period of time, and at lower frequency in areas with more recent invasion. Spore detection of seasonal pathogens showed a temporal pattern similar to that of disease reports. Overall, our study provides a proof of concept that permanent aerobiological networks combined with molecular methods may provide a useful tool for large-scale surveillance of forest pathogens.     

Biological characterization of bovine herpesvirus 1 recombinants possessing the vaccine glycoprotein E negative phenotype

Intramolecular recombination is a frequent event during the replication cycle of bovine herpesvirus 1 (BoHV-1). Recombinant viruses frequently arise and survive in cattle after concomitant nasal infections with two BoHV-1 mutants. The consequences of this process, related to herpesvirus evolution, have to be assessed in the context of large use of live marker vaccines based on glycoprotein E (gE) gene deletion. In natural conditions, double nasal infections by vaccine and wild-type strains are likely to occur. This situation might generate virulent recombinant viruses inducing a serological response indistinguishable from the vaccine one. This question was addressed by generating in vitro BoHV-1 recombinants deleted in the gE gene from seven wild-type BoHV-1 strains and one mutant strain deleted in the genes encoding gC and gE. In vitro growth properties were assessed by virus production, one step growth kinetics and plaque size assay. Heterogeneity in the biological properties was shown among the investigated recombinant viruses. The results demonstrated that some recombinants, in spite of their gE minus phenotype, have biological characteristics close to wild-type BoHV-1.     

Genetic Diversity of Pathogenic and Nonpathogenic Populations of Fusarium oxysporum Isolated from Carnation Fields in Argentina

ABSTRACT In order to elucidate the origin of Fusarium oxysporum f. sp. dianthi in Argentina, the genetic diversity among pathogenic isolates together with co-occurring nonpathogenic isolates on carnation was investigated. In all, 151 isolates of F. oxysporum were obtained from soils and carnation plants from several horticultural farms in Argentina. The isolates were characterized using vegetative compatibility group (VCG), intergenic spacer (IGS) typing, and pathogenicity tests on carnation. Seven reference strains of F. oxysporum f. sp. dianthi also were analyzed and assigned to six different IGS types and six VCGs. Twenty-two Argentinean isolates were pathogenic on carnation, had the same IGS type (50), and belonged to a single VCG (0021). The 129 remaining isolates were nonpathogenic on carnation and sorted into 23 IGS types and 97 VCGs. The same VCG never occurred in different IGS types. Our results suggest that the pathogen did not originate in the local populations of F. oxysporum but, rather, that it was introduced into Argentina. Given the genetic homogeneity within Argentinean isolates of F. oxysporum f. sp. dianthi, either IGS type or VCG can be used for the identification of the forma specialis dianthi currently in Argentina.     

Resistance to <Emphasis Type="Italic">Meloidogyne chitwoodi</Emphasis> Identified in Wild Potato Species

Meloidogyne chitwoodi (Columbia root-knot nematode, CRKN) can cause serious damage in potato production systems, decreasing tuber value in the fresh market and processing industries. Genetic resistance to CRKN was first identified from the wild diploid potato species Solanum bulbocastanum accession SB22 and was successfully introgressed into tetraploid potato breeding material. To expand the base of genetic resistance, 40 plant accessions representing nine wild potato species were screened for their resistance to M. chitwoodi. Greenhouse screening identified fifteen clones from S. hougasii, one clone from S. bulbocastanum, and one clone from S. stenophyllidium with moderate to high levels of resistance against three isolates of M. chitwoodi. Geographical mapping showed that the resistance sources identified in this and previous studies primarily originated in the states of Jalisco and Michoacán in west-central Mexico. These new sources of resistance will be introgressed into elite potato populations to facilitate the development of potato cultivars with durable resistance to M. chitwoodi.