| 1. |
- Legrand, M., et al.
(författare)
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Exposure to depleted uranium during development affects neuronal differentiation in the hippocampal dentate gyrus and induces depressive-like behavior in offspring
- 2016
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Ingår i: Neurotoxicology. - : Elsevier BV. - 0161-813X .- 1872-9711. ; 57, s. 153-162
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Tidskriftsartikel (refereegranskat)abstract
- The developing brain is known to be sensitive to uranium (U) and exposure to this element during postnatal brain development results in behavioral disorders in adulthood. Moreover, we have previously shown that U exposure during gestation and lactation affects neurogenesis, in particular neural cell proliferation and cell death. In this study, we investigated whether exposure to depleted U (DU) affects neuronal differentiation during prenatal and postnatal brain development. We assessed in situ expression of specific genes involved in neuronal differentiation and expression of neuronal protein markers. The effects of DU on neurobehavioral function were investigated in parallel. Neuronal differentiation involves many signaling pathways that regulate the balance between cell proliferation and the transition to neuronal differentiation. In the present study pregnant rats were exposed from gestational day (GD) 1 throughout lactation to postnatal day (PND) 21. Using in situ hybridization, our results show decreased expression of Wnt3a in the hippocampal neuroepithelium in GD 13 embryos from DU exposed dams and decreased expression of Notch1 and increased expression of Mash1 in the hippocampal and dentate neuroepithelia of GD 18 fetuses from DU exposed dams. Expression of the NeuroD and NeuroD2 genes was not modified in the hippocampal neuroepithelium of GD18 fetuses from DU exposed dams. There was no change in the expression of any of these genes in the dentate gyrus of PND 5 pups from DU exposed dams. No change in nestin or doublecortin immunestaining was observed in the prenatal or early postnatal stages. However, the number of doublecortin-positive cells increased in the granular cell layer of PND 21 pups from DU exposed dams. Finally, depressive-like behavior was induced in PND21 rats, without modification of locomotor and exploratory activities or of spatial memory. In conclusion, these results showed that exposure of pregnant and lactating rats to DU affects brain development by causing disturbed cell proliferation and neuronal differentiation at the prenatal stage. Moreover, this exposure increased the pool of immature neurons in the dentate gyrus and induced depressive-like behavior in neonatal rats. Therefore, these data strongly suggest that exposure to DU during gestation and lactation affects brain development in embryos, fetuses and neonates with behavioral consequences in the offspring.
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| 2. |
- Richards, Stephen, et al.
(författare)
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Genome Sequence of the Pea Aphid Acyrthosiphon pisum
- 2010
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 8:2, s. e1000313-
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Tidskriftsartikel (refereegranskat)abstract
- Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems.
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