Influence of chronic exposure to thiamethoxam and chronic bee paralysis virus on winter honey bees.

Co-exposure to pesticides and viruses is likely to occur in honey bee colonies. Pesticides can be present in pollen, nectar, and persist in stored food (honey and bee bread), and viruses can be highly prevalent in honey bee colonies. Therefore, the present study describes the influence of chronic co-exposure to thiamethoxam and Chronic bee paralysis virus (CBPV) on bee survival, virus loads, expression level of immune and detoxication genes, and pesticide metabolism Experiments were performed on honey bees collected from a winter apiary with reduced viral contaminations. No synergistic effect of co-exposure was observed on bee survival, nor on the ability of bees to metabolise the pesticide into clothianidin. However, we found that co-exposure caused an increase in CBPV loads that reached the viral levels usually found in overt infections. The effect of co-exposure on CBPV replication was associated with down-regulation of vitellogenin and dorsal-1a gene transcription. Nevertheless, the observed effects might be different to those occurring in spring or summer bees, which are more likelyco-exposed to thiamethoxam and CBPV and exhibit a different physiology

Gene × Environment interactions in autism spectrum disorders: role of epigenetic mechanisms.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Several studies support currently the hypothesis that autism etiology is based on a polygenic and epistatic model. However, despite advances in epidemiological, molecular and clinical genetics, the genetic risk factors remain difficult to identify, with the exception of a few chromosomal disorders and several single gene disorders associated with an increased risk for autism. Furthermore, several studies suggest a role of environmental factors in autism spectrum disorders (ASD). First, arguments for a genetic contribution to autism, based on updated family and twin studies, are examined. Second, a review of possible prenatal, perinatal, and postnatal environmental risk factors for ASD are presented. Then, the hypotheses are discussed concerning the underlying mechanisms related to a role of environmental factors in the development of ASD in association with genetic factors. In particular, epigenetics as a candidate biological mechanism for gene × environment interactions is considered and the possible role of epigenetic mechanisms reported in genetic disorders associated with ASD is discussed. Furthermore, the example of in utero exposure to valproate provides a good illustration of epigenetic mechanisms involved in ASD and innovative therapeutic strategies. Epigenetic remodeling by environmental factors opens new perspectives for a better understanding, prevention, and early therapeutic intervention of ASD

Role of virus/pesticides interactions in honey bee decline

Les abeilles domestiques subissent des pertes de colonies sans précédents, ce qui pourrait à terme avoir un fort impact économique compte tenu de leur apport à l’agriculture en service de pollinisation. Ces pertes sont définies comme causées par des stress multifactoriels. Cependant, l’impact de ces stress est en général testé séparément sur les individus ou les colonies. Les colonies sont connues pour concentrer les pesticides provenant de l’environnement à travers le pollen et le nectar récoltés mais aussi les pathogènes. L’étude de la co-exposition entre le thiaméthoxam, un insecticide néonicotinoïde, et deux virus de l’abeille, le DWV et le CBPV, a mis en évidence l’existence d’interactions entre chacun de ces virus et le pesticide. Diverses méthodes de transmission des virus ont été testées afin de s’approcher au mieux des conditions naturelles et une méthode de transmission du CBPV par contact répétable a été développée. Une cinétique de métabolisation du thiamethoxam a été effectuée pour la première fois, renseignant sur la forte probabilité d’excrétion du métabolite en conditions naturelles. Lors d’expérimentations en cagettes la co-exposition entre le CBPV et le thiaméthoxam à fortes doses chroniques a causé des mortalités synergiques, ou une augmentation des charges virales atteignant le seuil en nombre de copies virales connu pour déclencher des infections apparentes chez les abeilles. Les différences de résultats entre des abeilles provenant de colonies dans diverse conditions a souligné un effet de tolérance aux stress encore non étudié chez l’abeille domestique. En parallèle, la co-exposition au sein de la colonie entre le thiaméthoxam à une dose sublétale aigüe et le DWV a causé des premières sorties de butinage extrêmement précoces chez les abeilles, ainsi que de fortes proportions de premiers vols sans retour, ce qui pourrait à terme avoir un effet dévastateur sur les colonies. L’étude de la transcription de gènes suggère que les effets obtenus sur les charges virales en CBPV seraient dus à un effet du thiaméthoxam sur dorsal-1a, un facteur de l’immunité, et les sorties précoces à une baisse significative de la transcription de la vittelogénine, entrant en jeu dans les mécanismes de vieillissement, due au DWV. Le développement de clones moléculaires du DWV a été amorcé, ce qui pourra à terme permettre des études de génétique inverse sur ce virus, qui pourront expliquer ses modes de transmission et d’infections encore inconnus à ce jour.Domestic honeybees are suffering from unprecedented colony losses, which could at term have a strong economic impact, considering their part in crop pollination, notably. These losses are defined as caused by multifactorial stresses. However, the impact of these stresses is usually measured separately, on individuals or colonies. Colonies are known to concentrate pesticides from their environment through collection of pollen and nectar, but they also concentrate pathogens. The study of a co-exposure between thiamethoxam, a neonicotinoid insecticide, and two honeybee viruses, DWV and CBPV, has shed light on the existence of interactions between each of these viruses and the pesticide. Different virus transmission methods have been tested to be as close as natural conditions, and a repeatable CBPV transmission method through contact has been developed. Metabolisation kinetics of thiamethoxam have been obtained for the first time, underlining the strong probability for excretion of the metabolite in natural conditions. During caged experiments, the co-exposure experiments between thiamethoxam at high chronic doses and CBPV cause synergistic mortalities, or an increase in viral loads which reached the number of viral copies threshold associated with clinical signs in bees. The varying results between bees from colonies kept in different conditions underlined a stress tolerance effect yet to be studied in the honeybee. In parallel, co-exposure in colonies between sublethal doses of thiamethoxam and DWV caused extremely precocious first foraging trips in bees, as well as large proportions of bees never returning to the hive after their firs exit, which both could in the end have a devastating effect on the colonies. The study of gene transcripts suggests that the obtained effects on CBPV viral loads could be due to a negative effect of thiamethoxam on dorsal-1a, an immune factor, and the precocious trips to a significant down-regulation of vitellogenin, which takes part in honeybee aging, cause by DWV. The development of molecular clones of DWV and a DWV recombinant was initiated, which will in the future allow for reverse genetics studies on this virus, which will help explain their transmission and infection mechanisms that are still unknown to this day

Belgique : Avortement toujours interdit

Coulon Marianne. Belgique : Avortement toujours interdit. In: Les Cahiers du GRIF, n°26, 1983. Jouir. pp. 147-150

Rôle des intéractions virus/ pesticides dans le déclin des abeilles

Domestic honeybees are suffering from unprecedented colony losses, which could at term have a strong economic impact, considering their part in crop pollination, notably. These losses are defined as caused by multifactorial stresses. However, the impact of these stresses is usually measured separately, on individuals or colonies. Colonies are known to concentrate pesticides from their environment through collection of pollen and nectar, but they also concentrate pathogens. The study of a co-exposure between thiamethoxam, a neonicotinoid insecticide, and two honeybee viruses, DWV and CBPV, has shed light on the existence of interactions between each of these viruses and the pesticide. Different virus transmission methods have been tested to be as close as natural conditions, and a repeatable CBPV transmission method through contact has been developed. Metabolisation kinetics of thiamethoxam have been obtained for the first time, underlining the strong probability for excretion of the metabolite in natural conditions. During caged experiments, the co-exposure experiments between thiamethoxam at high chronic doses and CBPV cause synergistic mortalities, or an increase in viral loads which reached the number of viral copies threshold associated with clinical signs in bees. The varying results between bees from colonies kept in different conditions underlined a stress tolerance effect yet to be studied in the honeybee. In parallel, co-exposure in colonies between sublethal doses of thiamethoxam and DWV caused extremely precocious first foraging trips in bees, as well as large proportions of bees never returning to the hive after their firs exit, which both could in the end have a devastating effect on the colonies. The study of gene transcripts suggests that the obtained effects on CBPV viral loads could be due to a negative effect of thiamethoxam on dorsal-1a, an immune factor, and the precocious trips to a significant down-regulation of vitellogenin, which takes part in honeybee aging, cause by DWV. The development of molecular clones of DWV and a DWV recombinant was initiated, which will in the future allow for reverse genetics studies on this virus, which will help explain their transmission and infection mechanisms that are still unknown to this day.Les abeilles domestiques subissent des pertes de colonies sans précédents, ce qui pourrait à terme avoir un fort impact économique compte tenu de leur apport à l’agriculture en service de pollinisation. Ces pertes sont définies comme causées par des stress multifactoriels. Cependant, l’impact de ces stress est en général testé séparément sur les individus ou les colonies. Les colonies sont connues pour concentrer les pesticides provenant de l’environnement à travers le pollen et le nectar récoltés mais aussi les pathogènes. L’étude de la co-exposition entre le thiaméthoxam, un insecticide néonicotinoïde, et deux virus de l’abeille, le DWV et le CBPV, a mis en évidence l’existence d’interactions entre chacun de ces virus et le pesticide. Diverses méthodes de transmission des virus ont été testées afin de s’approcher au mieux des conditions naturelles et une méthode de transmission du CBPV par contact répétable a été développée. Une cinétique de métabolisation du thiamethoxam a été effectuée pour la première fois, renseignant sur la forte probabilité d’excrétion du métabolite en conditions naturelles. Lors d’expérimentations en cagettes la co-exposition entre le CBPV et le thiaméthoxam à fortes doses chroniques a causé des mortalités synergiques, ou une augmentation des charges virales atteignant le seuil en nombre de copies virales connu pour déclencher des infections apparentes chez les abeilles. Les différences de résultats entre des abeilles provenant de colonies dans diverse conditions a souligné un effet de tolérance aux stress encore non étudié chez l’abeille domestique. En parallèle, la co-exposition au sein de la colonie entre le thiaméthoxam à une dose sublétale aigüe et le DWV a causé des premières sorties de butinage extrêmement précoces chez les abeilles, ainsi que de fortes proportions de premiers vols sans retour, ce qui pourrait à terme avoir un effet dévastateur sur les colonies. L’étude de la transcription de gènes suggère que les effets obtenus sur les charges virales en CBPV seraient dus à un effet du thiaméthoxam sur dorsal-1a, un facteur de l’immunité, et les sorties précoces à une baisse significative de la transcription de la vittelogénine, entrant en jeu dans les mécanismes de vieillissement, due au DWV. Le développement de clones moléculaires du DWV a été amorcé, ce qui pourra à terme permettre des études de génétique inverse sur ce virus, qui pourront expliquer ses modes de transmission et d’infections encore inconnus à ce jour

Belgique : Avortement toujours interdit

Coulon Marianne. Belgique : Avortement toujours interdit. In: Les Cahiers du GRIF, n°26, 1983. Jouir. pp. 147-150

Microbiomes, plausible players or not in alteration of host behavior

International audienc

Synthesis and Antimicrobial Activity of Burkholderia-Related 4-Hydroxy-3-Methyl-2-Alkenylquinolones (HMAQs) and Their N-Oxide Counterparts

ABSTRACT: The Burkholderia genus offers a promising potential in medicine because of the diversity of biologically active natural products encoded in its genome. Some pathogenic Burkholderia spp. biosynthesize a specific class of antimicrobial 2-alkyl-4(1H)-quinolones, i.e., 4-hydroxy-3-methyl-2-alkenylquinolones (HMAQs) and their N-oxide derivatives (HMAQNOs). Herein, we report the synthesis of a series of six HMAQs and HMAQNOs featuring a trans-∆2 double bond at the C2-alkyl chain. The quinolone scaffold was obtained via the Conrad-Limpach approach while the (E)-2-alkenyl chain was inserted through Suzuki-Miyaura cross-coupling under microwave radiation without noticeable isomerization according to the optimized conditions. Subsequent oxidation of enolate-protected HMAQs cleanly led to the formation of HMAQNOs following cleavage of the ethyl carbonate group. Synthetic HMAQs and HMAQNOs were in vitro evaluated for their antimicrobial activity against different Gram-negative and Gram-positive bacteria as well as against fungi and yeasts. The biological results support and extend the potential of HMAQs and HMAQNOs as antimicrobials, especially against Gram-positive bacteria. We also confirm the involvement of HMAQs in the autoregulation of the Hmq system in Burkholderia ambifaria

Evolution du virus des ailes déformées (Deformed wing virus, DWV)

National audienc

Evolution du virus des ailes déformées (Deformed wing virus, DWV)

National audienc