In vivo Bioluminescence Imaging of Ca(2+) Signalling in the Brain of Drosophila

Many different cells' signalling pathways are universally regulated by Ca(2+) concentration [Ca(2+)] rises that have highly variable amplitudes and kinetic properties. Optical imaging can provide the means to characterise both the temporal and spatial aspects of Ca(2+) signals involved in neurophysiological functions. New methods for in vivo imaging of Ca(2+) signalling in the brain of Drosophila are required for probing the different dynamic aspects of this system. In studies here, whole brain Ca(2+) imaging was performed on transgenic flies with targeted expression of the bioluminescent Ca(2+) reporter GFP-aequorin (GA) in different neural structures. A photon counting based technique was used to undertake continuous recordings of cytosolic [Ca(2+)] over hours. Time integrals for reconstructing images and analysis of the data were selected offline according to the signal intensity. This approach allowed a unique Ca(2+) response associated with cholinergic transmission to be identified by whole brain imaging of specific neural structures. Notably, [Ca(2+)] transients in the Mushroom Bodies (MBs) following nicotine stimulation were accompanied by a delayed secondary [Ca(2+)] rise (up to 15 min. later) in the MB lobes. The delayed response was sensitive to thapsigargin, suggesting a role for intra-cellular Ca(2+) stores. Moreover, it was reduced in dunce mutant flies, which are impaired in learning and memory. Bioluminescence imaging is therefore useful for studying Ca(2+) signalling pathways and for functional mapping of neurophysiological processes in the fly brain

Prise en charge de l'hépatite C chronique chez des patients immigrés de l'Europe de l'Est à Poitiers

POITIERS-BU Médecine pharmacie (861942103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Thrombose portale aiguë chez le patient cirrhotique sans carcinome hépatocellulaire

POITIERS-BU Médecine pharmacie (861942103) / SudocSudocFranceF

Rôle des inhibiteurs de la pompe à proton dans les infections bactériennes chez le patient cirrhotique en période hémorragique

POITIERS-BU Médecine pharmacie (861942103) / SudocSudocFranceF

Etude d'une cohorte de patients porteurs du syndrome de Budd-Chiari ou d'une thrombose portale aiguë

POITIERS-BU Médecine pharmacie (861942103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Are the SSB-Interacting Proteins RecO, RecG, PriA and the DnaB-Interacting Protein Rep Bound to Progressing Replication Forks in Escherichia coli?

International audienceIn all organisms several enzymes that are needed upon replication impediment are targeted to replication forks by interaction with a replication protein. In most cases these proteins interact with the polymerase clamp or with single-stranded DNA binding proteins (SSB). In Escherichia coli an accessory replicative helicase was also shown to interact with the DnaB replicative helicase. Here we have used cytological observation of Venus fluorescent fusion proteins expressed from their endogenous loci in live E. coli cells to determine whether DNA repair and replication restart proteins that interact with a replication protein travel with replication forks. A custom-made microscope that detects active replisome molecules provided that they are present in at least three copies was used. Neither the recombination proteins RecO and RecG, nor the replication accessory helicase Rep are detected specifically in replicating cells in our assay, indicating that either they are not present at progressing replication forks or they are present in less than three copies. The Venus-PriA fusion protein formed foci even in the absence of replication forks, which prevented us from reaching a conclusion

Distinctive features of Egr transcription factor regulation and DNA binding activity in CA1 of the hippocampus in synaptic plasticity and consolidation and reconsolidation of fear memory.

International audienceActivity-dependent regulation of Egr1/Zif268, a transcription factor (TF) of the Egr family, is essential for stabilization of dentate gyrus synaptic plasticity and consolidation and reconsolidation of several forms of memory. The gene can be rapidly induced in selective brain circuits after certain types of learning or after recall. Here, we focused on area CA1 and examined regulation of Egr1, Egr2, and Egr3 mRNA and protein, and their DNA binding activity to the Egr response element (ERE) at different times after LTP in vivo and after learning and recall of a fear memory. We found LTP in CA1 leads to rapid induction of the three Egrs, however only Egr1 protein was overexpressed without a co-ordinated change in binding activity, indicating a fundamental difference between CA1 and dentate gyrus LTP. Our investigations in fear memory reveal that both learning and retrieval lead to an increase in binding of constitutively expressed Egr1 and Egr3 to the ERE, but not Egr2. Memory recall was also associated with increased Egr1 protein translation. The nature and temporal dynamics of these changes and tests for interactions between TFs suggest that in addition to ERE-mediated transcription, Egr1 in CA1 may interact with the TF c-Fos to regulate genes via other DNA response elements

Assembly of bacterial microchamber.

<p>A) Picture of an assembled microchamber connected to a reservoir at one side and to a needle at the other side, which will be connected later to a syringe pump. B) Schematic of a cross section of the microchamber. C) Image of bacteria growing in 2 dimensions.</p

A proteomic screen of Ty1 integrase partners identifies the protein kinase CK2 as a regulator of Ty1 retrotransposition

Abstract Background Transposable elements are ubiquitous and play a fundamental role in shaping genomes during evolution. Since excessive transposition can be mutagenic, mechanisms exist in the cells to keep these mobile elements under control. Although many cellular factors regulating the mobility of the retrovirus-like transposon Ty1 in Saccharomyces cerevisiae have been identified in genetic screens, only very few of them interact physically with Ty1 integrase (IN). Results Here, we perform a proteomic screen to establish Ty1 IN interactome. Among the 265 potential interacting partners, we focus our study on the conserved CK2 kinase. We confirm the interaction between IN and CK2, demonstrate that IN is a substrate of CK2 in vitro and identify the modified residues. We find that Ty1 IN is phosphorylated in vivo and that these modifications are dependent in part on CK2. No significant change in Ty1 retromobility could be observed when we introduce phospho-ablative mutations that prevent IN phosphorylation by CK2 in vitro . However, the absence of CK2 holoenzyme results in a strong stimulation of Ty1 retrotransposition, characterized by an increase in Ty1 mRNA and protein levels and a high accumulation of cDNA. Conclusion Our study shows that Ty1 IN is phosphorylated, as observed for retroviral INs and highlights an important role of CK2 in the regulation of Ty1 retrotransposition. In addition, the proteomic approach enabled the identification of many new Ty1 IN interacting partners, whose potential role in the control of Ty1 mobility will be interesting to study

Neuro-Otology: Problems of Dizziness, Balance and Hearing

© 2016 John Wiley & Sons, Ltd. This chapter expalins basic concepts of dizziness and vertigo, and discusses neuro-otological assessment for dizziness and vertigo. Dizziness is a substantial cause of morbidity, loss of time from work, repeated medical attendances and costly investigation - one study showed that on average more than four physicians were visited before precise diagnosis of a vestibular problem. The chapter presents the vestibular investigations, clinical disorders, and management of vestibular disorders. Direct observation of eye movements is useful, while recording techniques such as electronystagmography, video-oculography (VOG) and spiral coil recordings allow detailed evaluation and provide a permanent record for comparative purposes. Acute unilateral loss of vestibular function gives rise to symptoms of vertigo, nausea, vomiting, sweating, pallor and diarrhea. The chapter also discusses anatomy, physiology, definitions, introduction and basic concepts for hearing disorders. It describes the clinical examination of the ear and hearing, audiological investigations, auditory processing disorders, management of auditory disorders