Identification of Neural Outgrowth Genes using Genome-Wide RNAi

While genetic screens have identified many genes essential for neurite outgrowth, they have been limited in their ability to identify neural genes that also have earlier critical roles in the gastrula, or neural genes for which maternally contributed RNA compensates for gene mutations in the zygote. To address this, we developed methods to screen the Drosophila genome using RNA-interference (RNAi) on primary neural cells and present the results of the first full-genome RNAi screen in neurons. We used live-cell imaging and quantitative image analysis to characterize the morphological phenotypes of fluorescently labelled primary neurons and glia in response to RNAi-mediated gene knockdown. From the full genome screen, we focused our analysis on 104 evolutionarily conserved genes that when downregulated by RNAi, have morphological defects such as reduced axon extension, excessive branching, loss of fasciculation, and blebbing. To assist in the phenotypic analysis of the large data sets, we generated image analysis algorithms that could assess the statistical significance of the mutant phenotypes. The algorithms were essential for the analysis of the thousands of images generated by the screening process and will become a valuable tool for future genome-wide screens in primary neurons. Our analysis revealed unexpected, essential roles in neurite outgrowth for genes representing a wide range of functional categories including signalling molecules, enzymes, channels, receptors, and cytoskeletal proteins. We also found that genes known to be involved in protein and vesicle trafficking showed similar RNAi phenotypes. We confirmed phenotypes of the protein trafficking genes Sec61alpha and Ran GTPase using Drosophila embryo and mouse embryonic cerebral cortical neurons, respectively. Collectively, our results showed that RNAi phenotypes in primary neural culture can parallel in vivo phenotypes, and the screening technique can be used to identify many new genes that have important functions in the nervous system

Continuous interactions between the brain and the surrounding world

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A Method for Analysing Heating Demand and Energy Saving Actions for Regional Residential Building Stocks

In this paper a method is described, originally conceived during the compilation of the Energy and Environmental Regional Plan of Sicily, aimed to: a) set up a lay-out model of an overall regional residential estate into a certain number of different building and heating system types; b) calculate the energy needs of every single type according to the procedures established by the national and European regulations; The method is particularly designed to evaluate the possible energy savings from the implementation of different interventions concerning the envelope and the HVAC systems to the various building types. The method, although based on several assumptions, shows to be reliable enough and is also characterized by a simple structure easily adoptable by planners and technicians in their attempt to lead regional energy policies toward more sustainable paths. The method has been validated against the aggregate value of the real energy demand deriving from the regional energy balance