Biology subjects

Conti, E.

Publications and source records attributed to Conti, E..

5 recordsLinked to original sources

bioRxiv2018

Wide-field imaging of cortical neuronal activity with red-shifted functional indicators during motor task execution

Intracellular concentration of free calcium ions in neuronal populations can be longitudinally evaluated by using fluorescent protein indicators, called genetically encoded calcium indicators (GECIs). GECIs with long emission wavelengths are particularly attractive for deep tissue microscopy in vivo, and have the additional advantage of avoiding spectral overlap with commonly used neuronal actuators like Channelrhodopsin.\n\nHere we investigated the performances of selected red-shifted GECIs through an ex vivo characterization and in vivo imaging of cortical mouse activity during motor task execution. Cortical neurons were infected with adeno-associated virus (AAV) expressing one of the red GECI variants (jRCaMP1a, jRCaMP1b, jRGECO1a, jRGECO1b). First we characterized the transfection in terms of extension and intensity using wide-field fluorescence microscopy. Next, we used RCaMP1a to analyse the cortical neuronal activity during motor behaviour. To that end, wide-field fluorescent microscopy and a robotic device for motor control were combined for simultaneous recording of cortical neuronal-activity, force applied and forelimb position during task execution.\n\nOur results show that jRCaMP1a has sufficient sensitivity to monitor in vivo neuronal activity over multiple functional areas, and can be successfully used to perform longitudinal imaging in awake mice.

neuroscience↗

bioRxiv2018

Stavudine Reduces NLRP3-Inflammasome Activation and Upregulates Aβ-Autophagy

Alzheimers disease (AD) is associated with amyloid-beta (A{beta}) deposition and neuroinflammation, possibly driven by activation of the NLRP3 inflammasome. Nucleoside reverse transcriptase inhibitors (NRTI) hamper the assembly of the NLRP3 inflammasome; we analyzed whether stavudine (D4T), a prototypical NRTI, modulates A{beta}-mediated inflammasome activation; because neuroinflammation impairs A{beta} clearance by phagocytes, phagocytosis and autophagy were examined as well. THP-1-derived macrophages were stimulated in vitro with A{beta}42 alone or after LPS priming with/without D4T. NLRP3 and TREM2 expression was analyzed by RT-PCR, phagocytosis and ASC-Speck by AmnisFlowSight, NLRP3-produced cytokines by ELISA, authophagy by P-ELISA evaluation of P-ERK and P-AKT. Results showed that IL1{beta}, IL18 and caspase-1 were increased whereas A{beta}-phagocytosis and TREM2 were reduced in LPS+A{beta}42-stimulated cells. D4T reduced NLRP3 assembly as well as IL18 and caspase-1 production, but not IL1{beta}, phagocytosis, and TREM2. P-AKT expression was augmented and P-ERK was reduced by D4T, suggesting a stimulatory effect on autophagy. D4T reduces NLRP3 inflammasome-associated inflammation, possibly restoring autophagy, in an in vitro model of AD; it will be interesting to verify its possibly beneficial effects in the clinical scenario.

molecular biology↗

bioRxiv2018

High genetic diversity and presence of genetic structure characterise the Corso-Sardinian endemics Ruta corsica and Ruta lamarmorae (Rutaceae)

Corsica and Sardinia form one of the ten areas with highest biodiversity in the Mediterranean and are considered one of the priority regions for conservation in Europe. In order to preserve the high levels of endemism and biological diversity at different hierarchical levels, knowledge of the evolutionary history and current genetic structure of Corso-Sardinian endemics is instrumental. Microsatellite markers were newly developed and used to study the genetic structure and taxonomic status of Ruta corsica and Ruta lamarmorae, rare endemics of Corsica and Sardinia, respectively, and previously considered a single species. Our analyses identified high levels of genetic variation within each species (P=0.883, He=0.543 for R. corsica; P=0.972, He=0.627 for R. lamarmorae). Intrinsic traits of the species (hermaphroditism, proterandry and polyploidy) and island-dependent factors (i.e. age, origin and history of the islands) might explain the detected high levels of genetic variation. We discovered differentiation between R. corsica and R. lamarmorae, and genetic structure within each species, which are consistent with the observation of low dispersal ability for both species. Our genetic results support the recent taxonomic classification of R. corsica and R. lamarmorae as separate species and suggest that they diverge at only few loci. One R. corsica population (SA) strongly differed from all other studied populations and appeared to be the product of hybridization between the two species in STRUCTURE analyses. Our results provide important insights for the conservation of the two rare endemics. Further genetic analyses are recommended for R. lamarmorae and for population SA (R. corsica).

genetics↗

bioRxiv2017

Response of oriental xerophytes to the occidental industrial revolution

Since the Industrial Revolution, human activities have contributed substantially to climate change, by adding CO2 to the atmosphere, especially since the mid-20th century (the \"Great Acceleration\"). Climatic change does not have the same impact on different regions of the Earth, neither in the recorded past, nor in models of the future. Therefore, to anticipate on these changes, we need to understand and be able to predict the possible responses of the different regional vegetations of the world to these changes, and most significantly to increased drought conditions. The aim of this study is to understand the response of the xerophytes of the immense oriental Irano-Turanian bioregion to post-industrial global warming and to compare it with the response of the xerophytes of the neighbouring occidental Mediterranean bioregion. We measured stomata index and stomata density from 83 herbarium sheets (coll. 1821-2014) from species of the non-succulent xerophyte, Haplophyllum. We tested for differences before and after the \"Great Acceleration\" in both bioregions. SI decreased in the occidental species (significant only for abaxial leaf side), whereas SI significantly increased in the oriental species (both sides). We suggest that changes in both occidental and oriental species are linked to atmospheric CO2 due to the different constraints that act on their growth. In light-limited occidental species, atmospheric CO2 caused the stomata index decrease, whereas in the predominantly water-limited oriental species, increased drought stress and temperature (climatic change) caused stomata index increase. In conclusion, we propose that whereas atmospheric CO2 directly caused a decrease in stomata index in occidental xerophytes, it indirectly caused an increase in stomata index in oriental xerophytes via climate change (increase in aridity, drought stress, and temperature). This study highlights the considerable potential of research based on historical herbarium collections to answer ecological questions, especially regarding climatic change.

plant biology↗

bioRxiv2017

Rehabilitation Restores Cortical Activation Profiles And Stabilizes Synaptic Contacts After Stroke

Rehabilitation is the most effective treatment for promoting the recovery of motor deficits after stroke. Despite its importance, the processes associated with rehabilitative intervention are poorly understood. One of the most challenging experimental goals is to unambiguously link specific circuit changes induced by rehabilitation to improved behavior. Here, we investigate which facets of cortical remodeling are induced by rehabilitation by combining optical imaging and manipulation tools in a mouse model of stroke. We demonstrate the progressive restoration of cortical motor maps and of cortical activity in parallel with the reinforcement of inter-hemispheric connectivity after rehabilitation. Furthermore, we reveal that the increase in vascular density goes along with the stabilization of peri-infarct neural circuitry at synaptic level. The present work provides the first evidences that rehabilitation is sufficient to promote the combined recovery of distinct structural and functional features distinctive of healthy neuronal networks.

neuroscience↗