Rapid Visual Tests: Fast and Reliable Detection of Ochratoxin A

This paper reviews the early detection strategies that have been employed for the rapid monitoring of ochratoxin A (OTA) contamination of food. OTA, a mycotoxin mainly produced by some Aspergillus and Penicillium species, is found in cereals, coffee, wine, pork and grapes. To minimize the entry of this mycotoxin into the food chain, rapid diagnostic tools are required. To this end, the potential use of lateral flow devices has also been developed. In this study, we analyze the robustness of test strips using published methods for colorimetric detection. Different test formats are discussed, and challenges in the development of lateral flow devices for on-site determination of OTA, with requirements such as robustness, speed, and cost-effectiveness, are discussed

A combination of real-time PCR and high-resolution melting analysis to detect and identify CpGV genotypes involved in type I resistance

Cydia pomonella granulovirus, in particular CpGV-M isolate, is used as a biological control against the codling moth (CM), Cydia pomonella. As a result of intensive control over the years, codling moth populations have developed resistance against this isolate. This resistance is now called type I resistance. Isolates, among them, CpGV-R5, have been found that are able to overcome type I resistance. Both CpGV-M and CpGV-R5 are used in orchards to control the codling moth. High resolution melting (HRM) has been adapted to differentiate between CpGV-M and CpGV-R5 isolates. Specific PCR primers have been designed for the CpGV p38 gene, encompassing the variable region responsible for the ability to overcome resistance. Because each amplicon has a specific melting point, it is possible to identify the CpGV-M and CpGV-R5 genotypes and to quantify their relative proportion. This method has been validated using mixtures of occlusion bodies of each isolate at various proportions. Then, the HRM has been used to estimate the proportion of each genotype in infected larvae or in occlusion bodies (OBs) extracted from dead larvae. This method allows a rapid detection of genotype replication and enables the assessment of either success or failure of the infection in field conditions

Tracing baculovirus AcMNPV infection using a real time method based on ANCHORTM DNA labeling technology

Many steps in the baculovirus life cycle, from initial ingestion to the subsequent infection of all larval cells, remain largely unknown; primarily because it has hitherto not been possible to follow individual genomes and their lineages. Use of ANCHORTM technology allows a high intensity fluorescent labelling of DNA. When applied to a virus genome, it is possible to follow individual particles, and the overall course of infection. This technology has been adapted to enable labelling of the baculovirus Autographa californica Multiple NucleoPolyhedroVirus genome, as a first step to its application to other baculoviruses. AcMNPV was modified by inserting the two components of ANCHORTM: a specific DNA-binding protein fused to a fluorescent reporter, and the corresponding DNA recognition sequence. The resulting modified virus was stable, infectious, and replicated correctly in Spodoptera frugiperda 9 (Sf9) cells and in vivo. Both budded viruses and occlusion bodies were clearly distinguishable, and infecting cells or larvae allowed the infection process to be monitored in living cells or tissues. The level of fluorescence in the culture medium of infected cells in vitro showed a good correlation with the number of infectious budded viruses. A cassette that can be used in other baculoviruses has been designed. Altogether our results introduce for the first time the generation of autofluorescent baculovirus and their application to follow infection dynamics directly in living cells or tissues

Hydrochemical Characterization and Assessment of Groundwater Quality in the Mining Environment of Afema Township (South-East of Côte d’Ivoire)

Afema Township, located in the department of Aboisso, was mined from 1992 to 1998. At the end of the exploitation, the sites did not undergo any real rehabilitation work. In order to determine the impact of these mining activities on the physicochemical characteristics and quality of groundwater, this study was undertaken. The results of the water analyses collected in the mining area were processed using Piper's triangular diagram and Principal Component Analysis (PCA). The methodological approach consisted, first of all, in determining the hydro-facies of the waters studied, then in dividing them into different groups on the basis of their hydro-chemical similarity and in identifying the factors likely to explain both the origin of the parameters studied and their correlation. Finally, the overall quality of these waters was estimated from the calculation of the quality index. The results showed that the waters studied were divided into two main families: chloride-calcium-magnesium waters and bicarbonate-calcium-magnesium waters. They were on the whole weakly mineralized, with an average electrical conductivity of 195.76 μS.cm-1. This mineralization was controlled by two essential phenomena, the residence time of water in the aquifers and surface infiltration and leaching from unsaturated ground. The physico-chemical quality of the groundwater studied complied with the standards of potability recommended by the WHO. However, the results also showed high levels of cadmium (0.052 mg.L-1) and lead (0.058 mg.L-1); this explained the overall poor quality of these waters according to the water quality index. Thus, the studied waters presented a real risk for human consumption. The consumption of these waters by local communities exposes them to health risks

Hydrochemical Characterization and Assessment of Groundwater Quality in the Mining Environment of Afema Township (South-East of Côte d’Ivoire)

Afema Township, located in the department of Aboisso, was mined from 1992 to 1998. At the end of the exploitation, the sites did not undergo any real rehabilitation work. In order to determine the impact of these mining activities on the physicochemical characteristics and quality of groundwater, this study was undertaken. The results of the water analyses collected in the mining area were processed using Piper's triangular diagram and Principal Component Analysis (PCA). The methodological approach consisted, first of all, in determining the hydro-facies of the waters studied, then in dividing them into different groups on the basis of their hydro-chemical similarity and in identifying the factors likely to explain both the origin of the parameters studied and their correlation. Finally, the overall quality of these waters was estimated from the calculation of the quality index. The results showed that the waters studied were divided into two main families: chloride-calcium-magnesium waters and bicarbonate-calcium-magnesium waters. They were on the whole weakly mineralized, with an average electrical conductivity of 195.76 μS.cm-1. This mineralization was controlled by two essential phenomena, the residence time of water in the aquifers and surface infiltration and leaching from unsaturated ground. The physico-chemical quality of the groundwater studied complied with the standards of potability recommended by the WHO. However, the results also showed high levels of cadmium (0.052 mg.L-1) and lead (0.058 mg.L-1); this explained the overall poor quality of these waters according to the water quality index. Thus, the studied waters presented a real risk for human consumption. The consumption of these waters by local communities exposes them to health risks

Virus-based biological control facing climate change

International audienceClimate change will probably induce changes in the use of virus-based biocontrol agents at various levels. Climatic changes will affect host development, indirectly modifying virus behaviour. Invasive species will constitute potential new niches for virus populations, but also may reduce their traditional hosts. Introduction of new viruses adapted to such invasive species in their new geographic areas might be an appropriate strategy. Variation in UV radiation, in rain or wind will directly affect the survival or the availability of the virus for the appropriate hosts. Variation in temperatures influence insect host development, but also plant development, and will indirectly affect virus/host relationships.Instructions of use, timing and doses should be re-evaluated in function of new climate parameters. In addition, formulation changes might be required to optimise the persistence of virus-based products in new environmental conditions

Virus-based biological control facing climate change

International audienceClimate change will probably induce changes in the use of virus-based biocontrol agents at various levels. Climatic changes will affect host development, indirectly modifying virus behaviour. Invasive species will constitute potential new niches for virus populations, but also may reduce their traditional hosts. Introduction of new viruses adapted to such invasive species in their new geographic areas might be an appropriate strategy. Variation in UV radiation, in rain or wind will directly affect the survival or the availability of the virus for the appropriate hosts. Variation in temperatures influence insect host development, but also plant development, and will indirectly affect virus/host relationships.Instructions of use, timing and doses should be re-evaluated in function of new climate parameters. In addition, formulation changes might be required to optimise the persistence of virus-based products in new environmental conditions

Durabilité du contrôle du carpocapse des pommes et des poires (Cydia pomonella) avec le virus de la granulose (CpGV) (Résistance versus Virulence.)

Le Cydia pomonella granulovirus (CpGV) a été utilisé pendant plus de quinze ans pour le contrôle du carpocapse des pommes et des poires (C. pomonella). En 2004, une population résistante à l isolat viral CpGV-M utilisé au champ a été détectée pour la première fois dans un verger biologique du sud de la France. Le facteur de résistance de cette population a été estimé à 13 000 fois. Une colonie de laboratoire (RGV) a été établie à partir de ces insectes résistants, suivi d une introgression du caractère de résistance au sein d une colonie sensible de référence, Sv. La caractérisation génétique de la résistance a mis en évidence que la résistance est soit monogénique, soit contrôlée par un seul gène majeur, porté par le chromosome Z. Seul un faible coût biologique a été associé à ce caractère de résistance. Les points de blocage de l infection virale n ont pas été identifiés. Il semblerait néanmoins que la résistance ne soit pas liée au passage de la membrane péritrophique mais plutôt à un problème de réplication de l isolat viral CpGV-M dans la cellule hôte. Un nouvel isolat viral, NPP-R1, a été identifié et contournait partiellement la résistance des larves RGV au laboratoire. Des passages successifs ont été réalisés à partir de cet isolat NPP-R1 sur des larves RGV. Après 16 cycles d amplification, l isolat viral obtenu, 2016-r16, contournait totalement la résistance au laboratoire.The Cydia pomonella granulovirus (CpGV) has been used for fifteen years as a bioinsecticide in codling moth (C. pomonella) control. In 2004, an insect population with low susceptibility to the virus was detected for the first time in southeast France. The resistance factor was estimated to be 13,000-fold. A laboratory colony of codling moth that was resistant (RGV) to the CpGV-M isolate used in the field was established with resistant insects collected in field followed by an introgression of the resistant trait into a susceptible colony (Sv). The genetic characterization of the resistance showed that the resistance is either monogenic or controlled by a single major gene. The major resistant gene of RGV was localized on the sexual chromosome Z and only small fitness costs have been related to the resistant trait. Blocking points of the viral infection in RGV hosts have not been identified. Nevertheless, the investigations suggest that the peritrophic membrane is not implicated and that the resistance is rather related with a viral multiplication problem in the host cells. A new viral isolate called NPP-R1 was identified and overcome partially the resistance of RGV larvae in laboratory. Serial passages have been carried out on RGV larvae starting from the NPP-R1 isolate. After 16 cycles, the viral isolate, 2016-r16, totally overcome the RGV resistance in laboratory.PAU-BU Sciences (644452103) / SudocSudocFranceF

Transmission of the hereditary S character in Drosophila simulans: effects of aging and temperature treatments

International audienc

Caractérisation de pif, un gène de baculovirus essentiel pour l'infection de l'insecte

MONTPELLIER-SupAgro La Gaillarde (341722306) / SudocSudocFranceF