The Dachsous/Fat/Four-jointed Signalling Coordinates the Uniform Orientation of Planar Cell Alignement in the Drosophila Abdominal Epithelium

[eng] Within multicellular organism, mature tissues and organs reach high degrees of order in the arrangement of their constituent cells. During morphogenesis the emergence of long-range order is subjected to multiple and multilevel developmental constrains. Complex series of temporal and spatial instructions must be integrated to account for reproducible and stereotyped mature tissue arrangements. A remarkable example is given by mature epithelial monolayers were cells are ringed together in specific morphologies via cell-cell adhesion and show highly organized planar patterns. Cells in epithelial tissues acquire a precise planar geometry that is often, if not always, evenly aligned with the tissue axes. Little is still known on the cellular mechanisms governing the axial orientation of cell arrangement and planar polarity. The research presented in this Thesis addressed these issues through the analysis of the developing abdominal epithelium of Drosophila melanogaster. We found that the abdominal epithelial cells reach their final arrangement within about 2 days of pupation. During this time, the abdominal epithelial tissue undergoes extensive morphogenesis by tissue expansion and cellular remodelling. During expansion, epithelial cells divide randomly relative to the tissue axis while migrating dorsally, while during remodelling cell adjust their final position within the plane of the epithelium while migrating anteriorly. When cell movements arrest, a stable arrangement of the cells within the plane of the segmental field is attained. At this time, epithelial cells are oriented and aligned among each other and throughout the tissues invariably in parallel to the A/P axis. We indicated as uniform orientation of planar cell alignment (PCA). We found that the axis orientation of PCA is evolving in a spatiotemporal precise manner along the A/P axis, and that this dynamic oriented behaviour was progressively modulated through expansion and remodelling. We found that the Dachsous/Fat/Four-jointed planar polarity pathway was specifically involved in the orientation of PCA. The steps followed to reach the axial orientation of PCA over developmental times correlates with the pattern of expression of the Dachsous/Fat/Four- jointed pathway. Such correlation was sustained by genetic interferences with the pathway components. We found that both the dynamics of the axis orientation of PCA and the attainment of its uniformity along the A/P axis were disrupted rearrangements in dachsous, fat or four-jointed mutants. We further found that loss of the axial uniform orientation of PCA in these mutants is accompanied by an overall reduction in mutual cell alignment and in cell shape elongation. These effects were also sustained through local interference in the activity of the pathway through clonal analyses. Local changes in pathway components induce the mutant clones to minimize cell-cell contacts with surrounding wild-type cells, suggesting differential adhesive properties between dachsous, fat, four-jointed mutant cells and the rest of the tissue. Surprisingly, we found that this effect was also directional and that Dachsous has an instructive role in driving the axis orientation of PCA, possibly by regulating the Fat localization across the cells/tissue. Therefore, from these findings, we propose that the Dachsous/Fat/Four-jointed pathway guide the orientation of PCA by favouring oriented cell-cell contact adhesiveness between abdominal epithelial cells. In particular, different adhesive properties imposed throughout the cell perimeter by Ds-Ft heterodimeric interaction at opposite edges of the cell might align epithelial cells changing and orienting their shape. Over time this biased interaction responding to the Dachsous gradient would be reinforced in response to the activity of Dachsous and Four-jointed onto Fat.[spa] En los organismos multicelulares, tejidos y órganos tienen una disposición altamente organizada de las células que los constituyen. En particular, los tejidos epiteliales están constituidos por células que se disponen de manera ordenada con respecto a los ejes del cuerpo aunque los mecanismos que gobiernan esta disposición ordenada son poco conocidos. En esta tesis nos hemos focalizado en el estudio de los mecanismos que guían la orientación del eje celular en el plano de un epitelio en crecimiento. El epitelio abdominal de Drosophila constituye un sistema modelo para estudiar in vivo las dinámicas celulares que ocurren a lo largo de la morfogénesis tisular. Nuestros resultados demuestran que las células del epitelio abdominal empiezan a orientarse progresivamente llegando a una disposición espacial altamente ordenada. En esta disposición las células demuestran una preferencia en alinearse con el eje anteroposterior del tejido dando lugar a una orientación uniforme del alineamiento celular. Por otro lado, hemos descubierto que la vía de señalización de Dachsous/Fat/Four-jointed está involucrada en guiar el eje de orientación celular con respecto a el eje anteroposterior. Nuestros datos indican que los patrones de expresión de los genes dachsous, fat y four-jointed juegan un papel clave para el correcto alineamiento celular con el eje anteroposterior. De hecho, mutaciones en estos genes alteran el alineamiento espacial y afectan la elongación celular. Además, alteraciones locales en la actividad de cada uno de estos genes indican que están involucrados en la modulación orientada de los contactos adhesivos entre células vecinas. En resumen, estos resultados sugieren que la vía de señalización de Dachsous/Fat/Four- jointed tiene un papel clave en el alcance de una orientación celular uniforme a lo largo del tejido abdominal y, posiblemente, en otros epitelios

Ultrafast flow of interacting organic polaritons

The strong-coupling of an excitonic transition with an electromagnetic mode results in composite quasi-particles called exciton-polaritons, which have been shown to combine the best properties of their bare components in semiconductor microcavities. However, the physics and applications of polariton flows in organic materials and at room temperature are still unexplored because of the poor photon confinement in such structures. Here we demonstrate that polaritons formed by the hybridization of organic excitons with a Bloch Surface Wave are able to propagate for hundreds of microns showing remarkable third-order nonlinear interactions upon high injection density. These findings pave the way for the studies of organic nonlinear light-matter fluxes and for a technological promising route of dissipation-less on-chip polariton devices working at room temperature.Comment: Improved version with polariton-polariton interactions. 13 pages, 4 figures, supporting 6 pages, 6 figure

Tra affettività e diffidenza: un confronto tra le rappresentazioni sociali del cibo italiano e del cibo etnico

L’obiettivo di questo studio era di esplorare e mettere a confronto le rappresentazioni sociali del cibo italiano e del cibo etnico. A tale scopo, abbiamo coinvolto 74 italiani che hanno espresso la loro opinione relativamente alle due tipologie di cibo compilando un questionario a risposte aperte. I risultati indicano che la percezione del cibo italiano si fonda su concetti e categorie estremamente favorevoli, mentre, nella rappresentazione del cibo etnico, la sfiducia circa la sua salubrità sembra prevalere sull’attrattività esotica e sulle qualità organolettiche che pure gli vengono riconosciute. The aim of this study was to explore and compare the social representations of Italian and ethnic food. To this end, we involved 74 Italian participants who expressed their opinion on the two types of food in an open-ended questionnaire. The results indicate that the perception of Italian food is based on extremely favourable concepts and categories, while in the representation of ethnic food, mistrust about its wholesomeness seems to prevail over the exotic attractiveness and organoleptic qualities that are also recognized to it

Testing e validazione comparativa di coating idrofobizzanti per superfici in gelcoat

Nell’industria delle telecomunicazioni a supporto del settore aerospaziale, il mantenimento dell’efficacia e della sicurezza delle trasmissioni in condizioni ambientali estreme assume un’importanza crescente, in funzione della sempre maggiore diffusione dei siti trasmittenti/riceventi, operativi su scala planetaria. In questa cornice, si richiede che gli elementi a protezione dei dispositivi installati si dimostrino durevoli nel tempo anche quando esposti ad abbondanti precipitazioni, accumuli nevosi continuati o stratificazioni di ghiaccio, e improvvisi shock termici, garantendo nel contempo la fedeltà della trasmissione. Una marcata idrofobicità degli strati esterni delle coperture risulta quindi alla base per mantenerne l’efficacia nel tempo. Nel presente studio sono vengono riportati e confrontati i risultati di una serie di trattamenti idrofobizzanti su superfici di elementi tecnici in gelcoat costruiti per strutture radome, insieme a prove di resistenza meccanica, al fine di simulare in laboratorio le effettive condizioni di esposizione al danneggiamento. A questo scopo, le superfici sono state sottoposte a prove di bagnabilità tramite misurazione dell’ angolo di contatto e a test di resistenza meccanica alla scalfittura e di aderenza dei rivestimenti applicati, tramite Pencil Hardness Test, Cross-cut test, Scotch tape Test e pull-off Test. I campioni sono stati sottoposti ad un processo di invecchiamento accelerato mirato, alfine di valutare il mantenimento delle proprietà nel tempo. La comparazione multiparametrica dei risultati ottenuti ha reso possibile individuare i trattamenti che esibiscono performance eccellenti in termini di proprietà ultra-idrofobizzanti coniugate alla resistenza meccanica, anche mantenute nel tempo

Participatory processes in water governance in Senegal: the case study of the Ecopass project

Giving that participation represents a crucial element in any model of environmental governance today,the article - after describing participatory processes, related to the management of water resources andto the international development cooperation, and introducing water governance in Senegal - deals withthe features of the process implemented by the Ecopas project in four municipalities in the DakarMetropolitan area. The field of application is the governance of environmental resources with a specialfocus on water resources. The participatory processes accompanied all the activities carried out byEcopas and in particular they focused on the development of water and sanitation guidelines, the Atlasof issues and challenges of environmental governance, and the territorial pact for environmentconservation and promotion, which was signed by the municipalities targeted by the project. Theguiding approach was the structured dialogue, which promotes in an organised way the activeparticipation of local communities and Civil Society Organisations (Cso), and their interaction withpolicy makers.Essendo la partecipazione ormai un elemento cruciale in qualsiasi modello di governance ambientale,l'articolo - dopo un'introduzione sui processi partecipativi nella gestione delle risorse idriche e nellacooperazione internazionale allo sviluppo, e sulla governance dell'acqua in Senegal - analizza lemodalità di realizzazione dei processi partecipativi nel campo della governance delle risorse ambientalie in particolare delle risorse idriche, a partire dal progetto Ecopas in quattro comuni della periferia diDakar. I processi partecipativi hanno interessato tutte le attività svolte dal progetto Ecopas ed inparticolare quelle riguardanti lo sviluppo delle linee guida in materia di acqua e servizi igienicosanitari,l'atlante dei temi e delle sfide della governance inclusiva delle risorse ambientali, e il pattoterritoriale per la conservazione e la promozione dell'ambiente firmato dai comuni dell'area diintervento. L'approccio guida utilizzato è quello del dialogo strutturato, che promuove in modoorganizzato la partecipazione attiva delle comunità locali e delle Organizzazioni della Società Civile(Osc) e la loro interazione con i decisori politici

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p < .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p < .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come

Studio di fattibilita' per la realizzazione di un sistema di visione per applicazioni intravascolari

Studio di fattibilit

Imaging and analysis of tissue orientation and growth dynamics in the developing drosophila epithelia during pupal stages

Within multicellular organisms, mature tissues and organs display high degrees of order in the spatial arrangements of their constituent cells. A remarkable example is given by sensory epithelia, where cells of the same or distinct identities are brought together via cell-cell adhesion showing highly organized planar patterns. Cells align to one another in the same direction and display equivalent polarity over large distances. This organization of the mature epithelia is established over the course of morphogenesis. To understand how the planar arrangement of the mature epithelia is achieved, it is crucial to track cell orientation and growth dynamics with high spatiotemporal fidelity during development in vivo. Robust analytical tools are also essential to identify and characterize local-to-global transitions. The Drosophila pupa is an ideal system to evaluate oriented cell shape changes underlying epithelial morphogenesis. The pupal developing epithelium constitutes the external surface of the immobile body, allowing long-term imaging of intact animals. The protocol described here is designed to image and analyze cell behaviors at both global and local levels in the pupal abdominal epidermis as it grows. The methodology described can be easily adapted to the imaging of cell behaviors at other developmental stages, tissues, subcellular structures, or model organisms.Federica Mangione was supported by a JAE-CSIC predoctoral fellowship. The Martín-Blanco laboratory was funded from the Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia (BFU2014-57019-P and BFU2017-82876-P) and from the Fundación Ramón Areces

Video7_Photoablation at single cell resolution and its application in the Drosophila epidermis and peripheral nervous system.AVI

Tissues contain diverse cell populations that, together, make up physiologically functional units. A remarkable example is the animal epidermis, where neuronal and non-neuronal cells intermingle to allow somatosensory perception. In the peripheral nervous system (PNS), the tight association between heterogenous cell types poses challenges when the structural and physiological contributions of neuronal and surrounding cells need to be dissected with suitable precision. When genetic tools for cell-specific, spatiotemporally controlled gene expression are not available, targeted cell ablation represents a considerable obstacle. Here, we describe an efficient method to overcome this limitation and demonstrate its application to the study of the differentiating Drosophila epidermis and PNS. This methodology relies on the use of near infrared (NIR) femtosecond (fs) laser pulses for ablation of the desired cells at the desired time. We show how to confine the photodamage to the targeted cell to induce its death, without harming neighbouring tissues or structures. We validated our approach in the Drosophila PNS by studying the responses of photo-ablated neurons, non-neuronal cells, and the surrounding epidermis. Diverse cellular behaviours including cell extrusion, cell rearrangements and cell shape changes can be monitored in vivo immediately after damage, as well as for several hours post-ablation with high optical resolution using confocal microscopy. This methodology provides a flexible tool to ablate individual cells with high precision and study morphological responses to cell loss in targeted areas or neighbouring structures. We anticipate that this protocol can be easily adapted to other model systems and tissues.</p

Can Traditional Food Product Communication Convey Safety to the Younger Generations? The Role of Sustainable Packaging

Traditional food products (TFPs) represent a defining part of one's culture, identity, and heritage with crucial economic, cultural, and environmental benefits in society. Younger generations have a positive idea of TFPs, even if this does not lead to actual purchase, possibly due to the fact that they are often perceived to not meet safety criteria. This study focuses on product communication (CP) and packaging referring to the territory (PT) and to sustainability (SP) in order to verify if these have a direct or mediated impact on perceived product safety (PPS). A structural equation model was conducted on a sample of 1079 young Italian cheese consumers. The results allowed us to confirm the hypothesized impact of CP on PPS through the mediation of PT and, particularly, SP. SP has a crucial communicative role in the model, demonstrating the ability to enhance the perception of the safety of TFPs. This research adds to the knowledge in the field of TFPs, focusing on communication and sustainable packaging as crucial factors conveying healthiness, nutritiousness, and perceived safety, consequently leading to a greater diffusion of the products themselves in the market