Littérature scientifique sur le sujet « Long-distance signalling »

Understanding the mechanisms of cell-to-cell communication is one of the fundamental questions in biology and medicine. In particular, long-range signalling where cells communicate over several cell diameters is vital during development and homeostasis. The major morphogens, their receptors and intracellular signalling cascades have largely been identified; however, there is a gap in our knowledge of how such signalling factors are propagated over a long distance. In addition to the diffusion-based propagation model, new modalities of disseminating signalling molecules have been identified. It has been shown that cells can communicate with direct contact through long, thin cellular protrusions between signal sending and receiving cells at a distance. Recent studies have revealed a type of cellular protrusion termed ‘airinemes’ in zebrafish pigment cell types. They share similarities with previously reported cellular protrusions; however, they also exhibit distinct morphology and features. Airinemes are indispensable for pigment pattern development by mediating long-distance Delta-Notch signalling between different pigment cell types. Notably, airineme-mediated signalling is dependent on skin-resident macrophages. Key findings of airineme-mediated intercellular signalling in pattern development, their interplay with macrophages and their implications for the understanding of cellular protrusion-mediated intercellular communication will be discussed.

Abstract Be it a small herb or a large tree, intra- and intercellular communication and long-distance signalling between distant organs are crucial for every aspect of plant development. The vascular system, comprising xylem and phloem, acts as a major conduit for the transmission of long-distance signals in plants. In addition to expanding our knowledge of vascular development, numerous reports in the past two decades revealed that selective populations of RNAs, proteins, and phytohormones function as mobile signals. Many of these signals were shown to regulate diverse physiological processes, such as flowering, leaf and root development, nutrient acquisition, crop yield, and biotic/abiotic stress responses. In this review, we summarize the significant discoveries made in the past 25 years, with emphasis on key mobile signalling molecules (mRNAs, proteins including RNA-binding proteins, and small RNAs) that have revolutionized our understanding of how plants integrate various intrinsic and external cues in orchestrating growth and development. Additionally, we provide detailed insights on the emerging molecular mechanisms that might control the selective trafficking and delivery of phloem-mobile RNAs to target tissues. We also highlight the cross-kingdom movement of mobile signals during plant–parasite relationships. Considering the dynamic functions of these signals, their implications in crop improvement are also discussed.

Nodulation in legumes provides a major conduit of available nitrogen into the biosphere. The development of nitrogen-fixing nodules results from a symbiotic interaction between soil bacteria, commonly called rhizobia, and legume plants. Molecular genetic analysis in both model and agriculturally important legume species has resulted in the identification of a variety of genes that are essential for the establishment, maintenance and regulation of this symbiosis. Autoregulation of nodulation (AON) is a major internal process by which nodule numbers are controlled through prior nodulation events. Characterisation of AON-deficient mutants has revealed a novel systemic signal transduction pathway controlled by a receptor-like kinase. This review reports our present level of understanding on the short- and long-distance signalling networks controlling early nodulation events and AON.

In the central nervous system, ionotropic Glutamate Receptors (iGluRs) are tetrameric ligand-gated non-selective cation channels. They have been linked to learning and memory as well as to neurodegenerative pathologies such as Alzheimer disease. Thus, they are among the best characterized channels in animals. Animals and plants share this class of proteins. Plant Glutamate Receptors-like (GLRs) have been implicated in stomata movement regulation, pollen tube growth, long-distance signalling, root development and defence against pathogens. However, to date few details are known about their basic properties and functions, such as binding activity, ion transportation, sub-cellular localization, subunits interaction, desensitization etc. My PhD project focused on two GLR isoforms in Arabidopsis thaliana, AtGLR3.3 and AtGLR3.7 (hereafter called ‘AtGLR3.x’). Being putative amino acids-gated Ca2+-permeable channels, I tested the hypothesis that the two isoforms could handle Ca2+ dynamics upon amino acids challenge. Remarkably, Arabidopsis Col-0 plants show a transient elevation of cytosolic Ca2+ at the root tip meristematic zone upon amino acids treatment. Ablation of the AtGLR3.3 abolished the increase of Ca2+ concentration whereas loss of-function mutants for AtGLR3.7 showed enhanced Ca2+ rises in response to amino acids. Additionally, when the double mutant glr3.3glr3.7 was challenged with amino acids, mirrored the glr3.3 null-response. These results strongly suggested that the two AtGLRs could assemble in a channel where GLR3.3 would act as main scaffold and GLR3.7 would negatively regulate the biophysical properties. Being AtGLR3.x also expressed in the vascular tissues and in the cells of the floral abscission zone, we also assayed the role of AtGLR3.x in the generation/propagation of long-distance Ca2+ waves that occurs between stems and inflorescence apexes of Arabidopsis plants subjected to flaming. In the future, our efforts will be aimed at understanding whether the predicted amino acid sensing of GLRs is also required for the long-distance signalization.

Nel corso della loro vita le piante, essendo organismi sessili, sono continuamente soggette a cambiamenti ambientali che necessitano di essere accuratamente percepiti, a cui devono seguire appropriate risposte sia a livello locale che sistemico che ne garantiscano la sopravvivenza. Il calcio (Ca2+) è uno ione che agisce come importante secondo messaggero in tutti gli esseri viventi, in grado di accoppiare la percezione di uno stimolo extracellulare a peculiari risposte intracellulari. La specificità di trasduzione del segnale basata sul Ca2+ è ottenuta grazie alla generazione di transienti incrementi della sua concentrazione citosolica ([Ca2+]cyt), specifici nella loro evoluzione spaziale e temporale, alla quale ci si riferisce come “Ca2+ signatures”. La decodifica delle “Ca2+ signatures” da parte di proteine capaci di legare il Ca2+ permette la messa in atto di appropriate risposte fisiologiche. Nelle piante, è stato documentato che transienti variazioni citosoliche di Ca2+ sono coinvolte in svariati processi fisiologici che includono lo sviluppo della radice, lo sviluppo del tubetto pollinico e il processo di fecondazione, la risposta a stress abiotici, la regolazione dell’interazione pianta-microbo. Transienti incrementi nella [Ca2+]cyt con caratteristica intensità, frequenza, dinamica e durata sono generati dalla azione orchestrata di sistemi di influsso ed efflusso del Ca2+, che includono canali, pompe e scambiatori del Ca2+ che sono localizzati a livello delle membrane cellulari. Data l’importanza e l’universalità della trasduzione del segnale basata sul Ca2+, risulta essere di primaria importanza l’identificazione degli attori molecolari che governano la generazione dei segnali Ca2+. In questo contesto, lo studio delle dinamiche del Ca2+ in vivo rappresenta un potente strumento investigativo. Nel corso del mio dottorato di ricerca, ho esplorato il meraviglioso mondo del “Ca2+ imaging” utilizzando il vasto universo di Biosensori fluorescenti per il Ca2+ geneticamente codificati. Ho appreso e affinato tecniche per produrre immagini di alta qualità rappresentative di dinamiche del Ca2+ in vivo, sia a livello di intero organismo che a singola cellula. Le competenze che ho acquisito mi hanno permesso di contribuire a vari progetti tutti accomunati da quello che è un comune denominatore, ovvero il ruolo cardine del Ca2+ nella regolazione di svariati processi di trasduzione del segnale. Mi sono avventurato nello studio di vari aspetti legati alla segnalazione del Ca2+ tra cui: (i) gli aumenti della [Ca2+]cyt indotti nelle cellule dell’apice radicale in risposta a differenti amminoacidi, contribuendo a definire i determinanti molecolari sottostanti a tali risposte (Alfieri et al., 2020); (ii) la caratterizzazione dei transienti incrementi della [Ca2+]cyt indotti da auxine naturali e da molecole analoghe dell’auxina, e la decifrazione del ruolo di alcuni attori molecolari coinvolti nella genesi delle risposte [Ca2+]cyt indotte da auxina (Wang, Himschoot, Grenzi et al., 2022); (iii) lo sviluppo di un nuovo biosensore per il Ca2+ geneticamente codificato per indagare il ruolo del reticolo endoplasmico nella modellazione delle “Ca2+ signatures” in processi di sviluppo, così come in risposta a vari stimoli (Resentini, Grenzi et al., 2021); (iv) l’effetto di modulazione che alcuni composti chimici hanno sulle oscillazioni spontanee nella [Ca2+]cyt delle cellule di guardia che governano l’apertura e la chiusura degli stomi. Ho inoltre contribuito alla scrittura di reviews legate al mondo del “Ca2+ signalling” in pianta. Tutti i lavori pubblicati, così come i lavori in preparazione, sono allegati al termine di questa dissertazione, alla quale rimando gentilmente il lettore. Qui presenterò il lavoro portato avanti nel contesto del mio progetto di dottorato, il quale si è focalizzato principalmente alla comprensione dei meccanismi rapidi di segnalazione a lunga distanza. Le risposte sistemiche sono governate da eventi di segnalazione a lunga distanza che richiedono l’attività dei Recettori del Glutammato (GLRs). I GLRs sono proteine omologhe ai Recettori del Glutammato animali (iGluRs), ovvero canali ionici attivati da ligando presenti nel sistema nervoso centrale. Nonostante negli animali è chiaro che gli iGluRs mediano il passaggio di ioni a seguito del loro legame con il L-Glutammato, il meccanismo attraverso cui i GLRs sono attivati in pianta è ancora largamente discusso. Ad esempio, non si è ancora a conoscenza se il legame dell’aminoacido ai GLRs sia realmente necessario per la loro attivazione. In questo lavoro di tesi, analizzando i dati della struttura cristallografica del Dominio di Legame all’ amminoacido (LBD) del AtGLR3.3 di Arabidopsis thaliana, abbiamo identificato dei residui amminoacidici coinvolti nel legame del glutammato. Abbiamo dunque introdotto mutazioni puntiformi nella sequenza genomica del AtGLR3.3 per inficiare o abolire la sua abilità di legare il ligando amminoacidico, e con i costrutti ottenuti abbiamo eseguito una complementazione genetica dei mutanti knock out per il gene GLR3.3 (glr3.3-1 e glr3.3-2). Combinando analisi di imaging, genetica, e bioelettronica, dimostriamo che un danno a livello della foglia, come una ferita o una bruciatura, e l’applicazione di uno stress ipoosmotico alla radice, inducono l’aumento sistemico nella concentrazione apoplastica di L-Glutammato che attiva i GLRs attraverso il legame al loro LBD. Inoltre, il nostro lavoro supporta l’evidenza che gli eventi di segnalazione a lunga distanza siano governati da cambiamenti nello stato di turgore della pianta e che i GLRs siano a valle di essi.
Throughout their life plants, being sessile organisms, are continuously exposed to environmental challenges that need to be properly perceived and that require appropriate local and systemic responses. Calcium ion (Ca2+) is a key second messenger in all living beings that couples the perception of extracellular stimuli to characteristics intracellular responses. The specificity of the Ca2+-based signalling is achieved through the generation of specific spatial and temporal transient elevations in the cytosolic Ca2+ concentration [Ca2+]cyt, which are referred to as “Ca2+ signatures”. The interplay of Ca2+ signatures with a toolkit of cognate Ca2+-binding proteins that decode these increases allow the plant to implement a series of tailored physiological responses (e.g., gene expression, metabolism, developmental reprogramming) to withstand the stress. In plants, transient increases in the [Ca2+]cyt have been documented to be involved in several physiological processes including root or pollen tube growth and fertilization, abiotic stress responses, plant-microbe interaction. Ca2+ transients with unique magnitude, frequency, shape, and duration are generated by the orchestrated action of Ca2+ influx and efflux systems that include Ca2+ channels, pumps, and exchangers located at different cellular membranes. Given the importance and universality of Ca2+-based signalling, the identification of actors of the molecular machinery that govern the generation of Ca2+ signals is of primary importance. In this context, the study of Ca2+ dynamics in vivo represents a powerful tool. In the frame of my PhD, I explored the marvellous world of Ca2+ imaging using some of the instruments made available from a vast universe of genetically encoded fluorescent Ca2+ biosensors. I learned and refined techniques to produce high-end images of in vivo Ca2+ dynamics both at the entire organism and single-cell level. The expertise that I acquired allowed me to contribute to different projects, all unified by the common denominator that is the master regulatory role of Ca2+ in many signalling processes. I therefore contributed to the study of: (i) the [Ca2+]cyt responses of root tip cells in response to different amino acids, helping to define the molecular determinants involved in the process (Alfieri et al., 2020); (ii) the characterization of [Ca2+]cyt transients induced by the administration of natural auxins and auxin analogues, and the deciphering of the role of molecular actors involved in the genesis of the auxin-induced [Ca2+]cyt response (Wang, Himschoot, Grenzi et al., 2022); (iii) the development of a novel genetically encoded Ca2+ biosensors to unravel the role of the endoplasmic reticulum in the shaping of the Ca2+ signature in developmental processes, as well as in response to various stimuli (Resentini, Grenzi et al., 2021); (iv) the modulatory effects of chemicals on the spontaneous [Ca2+]cyt oscillations of guard cells that govern the opening and closing of stomata. I also contributed to the preparation of reviews linked to the field of Ca2+ signalling. All the published manuscripts, as well as works in preparation, are attached at the end of this dissertation, to which I kindly redirect the readers. Here, I am presenting the main work of my PhD project which focused on the understanding of how local damages can trigger inducible defence mechanisms in systemic organs and tissues. Systemic responses are mediated by long-distance signalling that requires the activity of Glutamate Receptor-Like channels (GLRs). GLRs are homologs of animal Ionotropic Glutamate Receptors (iGluRs) which are ligand-gated cation channels in the central nervous system. Even though iGluRs are gated through the binding with the L-Glutamate, the mechanism throughout GLRs are activated in planta is poorly understood. As an example, we still do not know if the GLRs binding of amino acids is necessary for their activity. In this PhD thesis, we took the advantage of the recently obtained crystal structure of the Arabidopsis thaliana AtGLR3.3 Ligand Binding Domain (LBD) to identify residues involved in the amino acid-binding. We, therefore, introduced single point mutations in the genome sequence of the AtGLR3.3 gene to prevent or abolish its amino acid-binding, and with the obtained constructs we complemented the glr3.3 KO. By combining high-end imaging, genetics, and bioelectronics we prove that leaf injury, such as wound and burn, and root-applied hypo-osmotic stress induce the systemic apoplastic increase of L-Glutamate that activates GLR channels through their LBD. In addition, our work supports the evidence that long-distance signalling is governed by a systemic change in the turgor state and that GLRs are downstream of it.

The molecular pathogenesis of Alzheimer’s disease (AD) is still controversial, although genetic and cell biology findings indicate accumulation of Aβ, especially in soluble oligomeric conformation, as the driving force of synaptic dysfunction with concomitant activation of complex cascade of molecular events leading to dementia. In the last few years, several studies aimed at understanding how Aβ accumulation and assembly compromise synaptic structure and function of excitatory synapses. In this study, we evaluated how Aβ can affect the local and the long-distance trafficking, since the alteration of these mechanisms could represent a key determinant for synaptic dysfunction. We focused the attention on ADAM10, which activity prevents Aβ production. Notably the regulation of ADAM10 synaptic localization is neuronal activity-dependent, in particular LTP decrease, while LTD foster ADAM10 surface expression. Here we found that Aβ42 (500nM, 30 min) exposure results in an increase of ADAM10 synaptic availability. In particular, Aβ42 treatment leads to a decrease in the association between ADAM10 and AP2 complex, suggesting that the augment in ADAM10 synaptic localization is due to a decrease of the endocytosis. Interestingly, this mechanism is completely lost in the context of AD, suggesting that the increase in ADAM10 endocytosis, and thus the reduction of its activity towards APP, could be a synaptic mechanism of AD pathogenesis. In light of this consideration, we developed CPPs able to interfere with ADAM10 clathrin-mediated endocytosis and to restore the unbalance between exo- and endocytosis. This tool can be considered a potential disease-modifying strategy capable of modifying the progression of the disease and rescuing the pathological phenotype. Afterwards we describe a novel synapse-to-nucleus signaling pathway, involving the RNF10 protein, that specifically links activation of synaptic GluN2A-containing NMDARs to nuclear gene expression. In physiological conditions, RNF10 dissociates from the NMDAR complex in an activity-dependent manner and we provide compelling evidence for importin-dependent long-distance transport from synapto-dendritic compartments to the nucleus. These findings suggest that synaptonuclear trafficking of RNF10 is involved in the control of gene expression, which is necessary for synaptic plasticity in hippocampal neurons. Here we demonstrated that Aβ can affect RNF10 long-distance trafficking. In particular, during acute exposure, Aβ induces RNF10 translocation while in a chronic AD pathological context we found a reduction of the translocation, suggesting that RNF10 could be involved in AD pathogenesis.

Les plantes sont des organismes sessiles se développant dans un environnement hétérogène et fluctuant. La capacité d'acquisition des nutriments par le système racinaire est donc un caractère important pour leur croissance et leur développement.L'azote (N), notamment sous forme nitrate (NO3-), fait partie de ces éléments qui sont limitant pour la croissance des plantes mais aussi très mobiles dans le sol donc fréquemment distribués de façon hétérogène. Les plantes s'adaptent à cette contrainte en modulant le développement racinaire ainsi que la capacité de transport de ce nutriment dans les différentes parties du système racinaire en fonction de la disponibilité en NO3- et du besoin en azote (N) de la plante entière. Cette adaptation repose donc sur la combinaison de deux voies de signalisation, i) une signalisation locale dépendante de la disponibilité en NO3- dans le milieu extérieur ii) une signalisation longue distance (ou systémique) racines-feuilles-racines relative au besoin en N de la plante entière.Toutefois, les bases moléculaires de la signalisation longue distance comme les mécanismes de régulation qui y sont associés ne sont pas totalement connus. Ils reposent sur l'intégration au niveau des parties aériennes de signaux d'origine racinaire, provenant des racines exposées au NO3- mais aussi de celles qui en sont privées. Les parties aériennes jouent alors un rôle majeur dans la modulation de la physiologie et du développement racinaire en condition de disponibilité hétérogène en NO3-. Des études précédentes ont montré que la biosynthèse de cytokinines est essentielle pour la mise en place de cette réponse adaptative. De plus, il est connu qu'après un apport de NO3-, la biosynthèse de cette hormone dans les racines puis son accumulation dans les parties aériennes est augmentée. Dans ce contexte, nous avons émis l'hypothèse que les cytokinines pourraient correspondre à un messager racines/feuilles important pour la signalisation systémique NO3--dépendante.L'objectif de mon projet de thèse consistait à comprendre comment les parties aériennes contrôlent l'acquisition racinaire du NO3- en condition de disponibilité hétérogène en NO3-. Pour reproduire cette condition en laboratoire, le système de 'split-root', permettant de séparer le système racinaire en deux parties isolées pouvant être traitées différemment, a été utilisé pour exposer les plantes à différentes conditions de disponibilité en NO3-. Dans ces différentes conditions, les réponses moléculaires, métaboliques et physiologiques ont été caractérisées chez des plantes sauvages d'Arabidopsis et comparées à celles de mutants affectés dans la biosynthèse, le transport acropetal ou encore dans la perception des cytokinines. La combinaison de ces différentes approches m'a ainsi permis de démontrer que les cytokinines, et plus précisément les trans-zéatines, sont effectivement un messager racines-feuilles crucial pour la mise en place des réponses de la racine à une disponibilité hétérogène en NO3-. De plus, j'ai montré que l'apport hétérogène en NO3- comparé à l'apport homogène entraîne une importante reprogrammation de l'expression génique dans les parties aériennes qui est largement dépendante de ce transport de trans-zéatines vers les feuilles. Enfin, l'intégration de ces données transcriptomiques au sein de réseaux géniques a permis d'identifier des gènes candidats intéressants comme acteurs possibles de la signalisation feuilles-racines
Plants are sessile organisms growing in a heterogeneous and fluctuating environment. Thus, foraging for nutrients is an important trait for plant growth and development. Nitrogen (N), especially as nitrate (NO3-) form, is one limiting element for plant growth but is also highly mobile in the soil leading to frequent heterogeneity distribution. Plants are managing this constraint through the regulation of root development and NO3- uptake in the different parts of the root system according to the spatial NO3- availability and the N needs of the whole plant. This adaptation relies on a dual signaling pathway involving i) a local signaling related to external NO3- supply and ii) a root-shoot-root long-distance (systemic) signaling related to the plant N needs..However, the molecular basis of the long-distance signaling as well as the regulatory mechanisms associated with, are not fully understood. They rely on the integration at the shoot level of signals originating from both NO3--supplied and N-deprived root parts. Therefore, the shoots have a key role for an efficient adaptation to heterogeneous NO3- environment through the adjustment of root physiology and development. Previously, cytokinin biosynthesis has been shown to be essential for both molecular and morphological root responses to NO3- heterogeneous environment. Moreover, it is known that upon NO3- supply, de novo biosynthesis of this hormone in the roots is increased along with its accumulation in the shoots. In this context, we hypothesized that cytokinins could correspond to an important root to shoot signal involved in NO3--dependent systemic signaling.The main objective of my PhD project was to decipher and understand how the shoots control root NO3- acquisition in response to spatial NO3- heterogeneity. To do so, we used the 'split-root' system, in which physically isolated roots of a same plant are challenged with different NO3- environments. In this framework, we characterized physiological, metabolic and molecular responses of Arabidopsis wild-type plants that we compared to responses of mutants impaired in cytokinin biosynthesis, acropetal transport or perception. The combination of these different approaches allowed me to demonstrate that cytokinins, and especially trans-zeatin species are indeed a root to shoot messenger that is crucial for root responses to spatial NO3- heterogeneity. Moreover, I have shown that NO3- heterogeneous supply compared to homogeneous supply triggers a substantial reprogramming of gene expression in aerial part, which largely depends on this trans-zeatin transport toward the shoots. Finally, the integration of these transcriptomic modifications into gene networks led to the identification of interesting candidate genes to characterize the shoot-to-root signaling

This book is about some of the ways in which the world got ready to be connected, long before the advent of the technologies and the concentrations of capital necessary to implement a global ‘network society’. It investigates the prehistory not of the communications ‘revolution’ brought about by advances in electronic digital computing from 1950 onwards, but of the principle of connectivity which was to provide that revolution with its justification and rallying cry. Connectivity’s core principle is that what matters most in any act of telecommunication, and sometimes all that matters, is the fact of its having happened. During the nineteenth century, the principle gained steadily increasing traction by means not only of formal systems such as the telegraph, but of an array of improvised methods and signalling devices. These methods and devices fulfilled not just an ever more urgent need, but a fundamental recurring desire, for near-instantaneous real-time communication at a distance. Connectivity became an end in itself: a complex, vivid, unpredictable romance woven through the enduring human desire and need for remote intimacy. Its magical enhancements are the stuff of tragedy, comedy, satire, elegy, lyric, melodrama, and plain description; of literature, in short. The book develops the concepts of signal, medium, and interface to offer, in its first part, an alternative view of writing in Britain from the Victorian era to modernism; and, in its second, case studies of European and African-American fiction, and of interwar British cinema, designed to open the topic up for further enquiry.

By applying the seriation method to a group of 129 assemblages distinguished by a ‘non-male’ model of grave furnishing and containing at least two distinctive metal objects, it was possible to divide the lifespan of the cemetery into three chronological stages. These were characterised by stylistically different (but interlocking) sets of ornaments and dress items. An attempt to relate these phases to the periodisation systems developed for the areas to the north, west, and south confirmed contacts with the Oder zone as early as during the early phase, which we synchronise with Ha C1b. What has also emerged in the course of the present study is another factor characteristic of this early phase, one that has not been taken into account in previous studies, namely the evidence of contacts with the northern lowland zone. These are legible mainly in the distinctive style of neck and hand ornaments: necklaces of the Wendelringe or unidirectionally twisted type, with loops or fastened with a hook, usually occurring no further south than Greater Poland, and bracelets with distant Pomeranian references. The presence of this style seems to have contributed in subsequent phases to the production of local types of ring ornaments (e.g., pointed necklaces of the Mąkolice type). The presence of northern bronzes of possibly such an early chronology (Ha C1) in the Polish Plain, especially at its southern edge, has so far been only sporadically reported, especially in the range of the Upper Silesian-Lesser Poland group. Nevertheless, contacts with the north at the turn of the Bronze Age and early Iron Age have already been suggested in the context of the northwards ‘diffusion’ of the idea of inhumation. early phase reveal strong influences coming evidently from the south, from the Moravian Gate region. This is indicated by the appearance of bracelets with thickened ends (e.g., Kietrz type) or richly decorated necklaces fastened with a hook (Domasław type) in many graves of this phase. The exact temporal relationship between the two groups of finds is difficult to determine – they appear inseparable on the seriation diagram (Figs. 4.1–2), with the Silesian Hallstatt style continuing much longer, into the middle phase. In addition, the early phase provides evidence that the Świbie community had access to very valuable goods from southern Europe, such as beads made of vitreous materials (glass and glassy faience, still scarce at the time) or flat iron axes with broad heads (Ärmchenbeile of type III3). It is with this phase that the most impressive burial in Świbie, grave 102, is connected. It belonged to a woman furnished with a local button diadem and the largest set of imports in the cemetery, comprising of a glass bead necklace with a unique ‘star’ shaped bead, a bronze harp fibula decorated with chains, a bronze necklace, and perhaps also bracelets (Garbacz-Klempka et al., Chapter 15). Another noteworthy burial from the early phase is grave 125, in which a dyed fabric of dense yarn, undoubtedly imported from eastern Alpine region, was found (Słomska-Bolonek, Antosik, Chapter 12). A phenomenon typical of the early phase is emphasising the status of some women (but from many families) by furnishing their burials not only with prestigious imports but also with sumptuous local ornaments. Among the latter, the most important markers of status and local identity (of traditional dress?) were headbands with sewn-on bronze (less often lead) buttons. In the burial ritual, the primacy of inhumation is evident. This means that an exclusively local population substrate, cultivating traditions derived from previous eras, continued to play significant role, while the role of exogamy was perhaps still limited. Most likely before the end of the early phase, and certainly in the middle phase (Ha C2), we observe a gradual disappearance of northern stylistic inspiration in ornament making. Meanwhile, permanent contacts with the strongly Hallstattized communities from the right-bank Upper Silesia and Central Silesia continued, noticeable mainly in the spectrum of ornaments. Some references to the necropolis at Domasław are evident (decorated necklaces, painted pottery), but there are also clear differences, including the lack of adoption of costume fastened with a brooch or brooches (Fibeltracht) and the absence of aristocratic burials furnished with swords. There are also no direct parallels in Świbie for sumptuous tomb constructions (chambered graves), although this may be due to the well- established local traditions of lining the bottoms of graves with wood, building grave boxes, or using coffins. The increasing occurrence of cremation, sometimes as burials added to earlier inhumation graves (resulting in ‘biritual graves’), may be seen as an expression of the increasing openness of the local population to external influences or as a move away from endogamy. All these phenomena become more pronounced in the late phase, which we synchronise with the developed Ha C2 and Ha D1. From this stage come most of the glass beads found in Świbie. This applies to both complete necklaces and beads placed to graves in smaller numbers, and the number of burials furnished with such beads is higher than in the early phase. Silesian painted vessels, essentially absent in the early phase, now appear in more than a dozen graves, both with and without indicators of high status (Chapter 5). Most of the graves with amber come from this phase. The growing frequency of these middle-class imports is indicative of increasing egalitarianism, which is also reflected by the insignificant proportion of late phase assemblages among the richest grave furnishings in the ranking developed for the cemetery as a whole (Fig. 5.2). This was not due to the disappearance of local ways of prestige signalling – traditional headbands (diadems), for example, are still present, and are even richer (up to 140 buttons). At the same time, from the late phase onwards, all locally manufactured types of ornaments (necklaces, pins, bracelets, ankle-rings) are basically made of iron. Morphologically, these are familiar types, but the raw material from which they are made gradually changes during the middle phase. The change in raw material is often accompanied by a simplification of the original patterns. Given all the evidence for long-distance networks becoming increasingly accessible for a growing proportion of the local community, the rise in popularity of cremation, evident in the late phase and especially towards the end of cemetery’s lifespan, should come as no surprise (Fig. 6.1), as this phenomenon remains, in our view, linked to the growing role of exogamy in marital exchange. The natural and increasingly important partners in this exchange were the Silesian populations, who were also the providers of the above-mentioned goods, and who had for centuries been traditionally following cremation as their burial rite. The most recent burials deposited at Świbie are cremation burials in large pots as urns, such as grave 486 with an iron belt clasp, dated to the turn of the Ha D1/D2 period, deposited on the northern edge of the necropolis.