Monoallelic deletion of the microRNA biogenesis gene Dgcr8 produces deficits in the development of excitatory synaptic transmission in the prefrontal cortex

Abstract Background Neuronal phenotypes associated with hemizygosity of individual genes within the 22q11.2 deletion syndrome locus hold potential towards understanding the pathogenesis of schizophrenia and autism. Included among these genes is Dgcr8, which encodes an RNA-binding protein required for microRNA biogenesis. Dgcr8 haploinsufficient mice (Dgcr8+/-) have reduced expression of microRNAs in brain and display cognitive deficits, but how microRNA deficiency affects the development and function of neurons in the cerebral cortex is not fully understood. Results In this study, we show that Dgcr8+/- mice display reduced expression of a subset of microRNAs in the prefrontal cortex, a deficit that emerges over postnatal development. Layer V pyramidal neurons in the medial prefrontal cortex of Dgcr8+/- mice have altered electrical properties, decreased complexity of basal dendrites, and reduced excitatory synaptic transmission. Conclusions These findings demonstrate that precise microRNA expression is critical for the postnatal development of prefrontal cortical circuitry. Similar defects in neuronal maturation resulting from microRNA deficiency could represent endophenotypes of certain neuropsychiatric diseases of developmental onset

Detection of Multiple Variants of Grapevine Fanleaf Virus in Single Xiphinema index Nematodes

Grapevine fanleaf virus (GFLV) is responsible for a widespread disease in vineyards worldwide. Its genome is composed of two single-stranded positive-sense RNAs, which both show a high genetic diversity. The virus is transmitted from grapevine to grapevine by the ectoparasitic nematode Xiphinema index. Grapevines in diseased vineyards are often infected by multiple genetic variants of GFLV but no information is available on the molecular composition of virus variants retained in X. index following nematodes feeding on roots. In this work, aviruliferous X. index were fed on three naturally GFLV-infected grapevines for which the virome was characterized by RNAseq. Six RNA-1 and four RNA-2 molecules were assembled segregating into four and three distinct phylogenetic clades of RNA-1 and RNA-2, respectively. After 19 months of rearing, single and pools of 30 X. index tested positive for GFLV. Additionally, either pooled or single X. index carried multiple variants of the two GFLV genomic RNAs. However, the full viral genetic diversity found in the leaves of infected grapevines was not detected in viruliferous nematodes, indicating a genetic bottleneck. Our results provide new insights into the complexity of GFLV populations and the putative role of X. index as reservoirs of virus diversity

Lewy Body Variant of Alzheimer's Disease: Selective Neocortical Loss of t-SNARE Proteins and Loss of MAP2 and α-Synuclein in Medial Temporal Lobe

Lewy bodies (LBs) appear in the brains of nondemented individuals and also occur in a range of neurodegenerative disorders, such as dementia with Lewy bodies (DLB) and Parkinson's disease. A number of people with a definite diagnosis of Alzheimer's disease (AD) also exhibit these intraneuronal inclusions in allo- and/or neocortical areas. The latter, referred to as Lewy body variant of AD (LBV), bears a clinical resemblance to AD in terms of age at onset, duration of illness, cognitive impairment, and illness severity. Since the presence of LBs is accompanied by neuronal cytoskeleton changes, it is possible that the latter may influence neuronal connectivity via alterations to the synaptic network. To address this, we examined the expression of synaptic proteins (synaptophysin, syntaxin, SNAP-25, and α-synuclein) and two cytoskeletal proteins (tau and MAP2) in the brain tissue of subjects enrolled in a population-based autopsy study (n = 47). They were divided into groups with no memory problems (control group, n = 15), LBV (n = 5), AD devoid of LBs (n = 17), cerebrovascular dementia (n = 3), and mixed dementia (n = 7). The LBV and AD groups had a similar degree of cognitive impairment and neuropathological staging in terms of Braak staging and CERAD score. In comparison with the control group and the dementia groups without LBs, the LBV group had significantly lower levels of syntaxin and SNAP-25 (23%) in the neocortex, and depletion of MAP2 (64%), SNAP-25 (34%), and α-synuclein (44%) proteins in the medial temporal lobes. These findings suggest that the t-SNARE complex deficit present in LBV may be associated with the presence of LB-related pathology and may explain the more profound cholinergic loss seen in these patients

Growth and reproduction of the slug Limax valentianus Férussac in experimental conditions

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Daily variation in the number of slugs under refuge traps

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Comparison between the control efficacy of Trichogramma evanescens Wetswood (Hymenoptera : Trichogrammatidae) and two Trichogramma cacoeciae Marchal strains against grapevine moth (Lobesia botrana Den. Schiff.), depending on their release density

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La plateforme de transformation de la vigne et exemple d’application en virologie

National audienceSuite au séquençage du génome de la vigne (Jaillon et al., 2007) une forte demande en analyse fonctionnelle chez la vigne a émergé. Une enquête réalisée auprès des différents acteurs (2008- 2009) a permis d’estimer les besoins et de co-définir le mode de fonctionnement attendu par les laboratoires. La plateforme est fonctionnelle depuis le printemps 2010. Elle fait appel à une méthode de transformation génétique/régénération de la vigne optimisée adaptée notamment à la lignée de Pinot Noir (P.N.) 40024. La transformation est réalisée sur des cals embryogènes obtenus à partir du filet des anthères. De l’anthère jusqu’à l’obtention d’une plantule régénérée conforme à la plante d’origine, 6 mois sont nécessaires et les cultures de cellules doivent être renouvelées tous les deux ans (Perrin et al 2001, 2004). Après avoir testé la capacité à la régénération des cals embryogènes, la transformation par Agrobacterium tumefaciens est réalisée avec comme marqueur de sélection soit la Green Fluorescent Protein (GFP), soit la résistance aux antibiotiques (hygromycine, kanamycine). A partir de 100 μl de PVC (Pack Cell Volume), 10 à 30 transformants indépendants peuvent être obtenus en 6 à 8 mois, en fonction des génotypes (41B, Chardonnay, P.N. 40024, Nemadex AB). La plateforme produit 10 plantes transgéniques indépendantes caractérisées par analyses moléculaires (RT-PCR) 8 mois environ après réception de la construction du requérant. Nous présenterons la méthodologie de transformation, le mode d’interaction plateforme/laboratoire demandeur, les coûts de prestation ainsi que les premiers résultats obtenus sur une analyse fonctionnelle de promoteur et sur la création de porte-greffes transgéniques pour une résistance aux virus

Host density-dependence of discovery and exploitation rates of egg patches of Lobesia botrana (Lepidoptera : Tortricidae) and Ephestia kuehniella (Lepidoptera : Pyralidae) by the parasitoid Trichogramma cacoeciae (Hymenoptera : Trichogrammatidae)

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Survey of natural populations of Trichogramma (Hym., Trichogrammatidae) in the vineyards of Alsace (France)

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RNAi-mediated resistance to Grapevine fanleaf virus and Arabis mosaic virus in transgenic Nicotiana benthamiana

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