Deux tombes féminines, atypiques et privilégiées, de la nécropole du Bas-Empire d’Arcis-sur-Aube (Champagne-Ardenne)

En 2002, une nécropole a été partiellement fouillée au sud de la commune d’Arcis-sur-Aube (Aube, Champagne-Ardenne). Cette opération a permis d’exhumer vingt-deux tombes datées entre la fin du IIIe et le milieu du IVe siècle. Malgré des pratiques de dépôt partagées par la plupart des défunts, deux tombes se distinguent. Ces deux fosses, aménagées avec un double coffrage, accueillent deux défuntes qui possèdent des dépôts très similaires. La qualité des dépôts, leur disposition dans la fosse, ainsi que la proximité des creusements, signalent une volonté du groupe de mettre en exergue ces deux femmes. De plus, une particularité dentaire encourage à voir entre elles un possible apparentement.In 2002, a necropolis to the south of the commune of Arcis-sur-Aube (Aube, Champagne-Ardenne) was excavated. Twenty-two tombs were exhumed and dated to between the end of the 3rd and middle of the 4th century. While most of the deceased were deposited in the same manner, two tombs differ from the others. These two pits, constructed a double coffering, contained two individuals with very similar grave goods. The quality of these objects, their arrangement in the pits, and the proximity of the pits to each other indicate that the group intended to highlight these two women. Moreover, a shared dental feature could indicate a kinship relationship between them.2002 wurden im Süden der Gemeinde Arcis-sur-Aube (Departement Aube, Champagne-Ardenne) bei der teilweisen Ausgrabung einer Nekropole 22 Bestattungen freigelegt, die zwischen das Ende des 3. und die Mitte des 4. Jh. datierten. Die Beigaben sind in den meisten Gräbern identisch. Nur zwei doppelt verschalte Gräber weisen Unterschiede auf. Hier ruhten zwei weibliche Verstorbene mit sehr ähnlichen Grabbeigaben. Deren Qualität, Anordnung in der Grube sowie die Nähe der beiden Grabstätten zu einander zeugen von dem Sonderstatus der beiden Frauen innerhalb der Gruppe. Eine Eigentümlichkeit der Zähne legt eine verwandtschaftliche Beziehung zwischen den Frauen nah

Bidirectional intraflagellar transport is restricted to two sets of microtubule doublets in the trypanosome flagellum

Intraflagellar transport (IFT) is the rapid bidirectional movement of large protein complexes driven by kinesin and dynein motors along microtubule doublets of cilia and flagella. In this study, we used a combination of high-resolution electron and light microscopy to investigate how and where these IFT trains move within the flagellum of the protist Trypanosoma brucei. Focused ion beam scanning electron microscopy (FIB-SEM) analysis of trypanosomes showed that trains are found almost exclusively along two sets of doublets (3–4 and 7–8) and distribute in two categories according to their length. High-resolution live imaging of cells expressing mNeonGreen::IFT81 or GFP::IFT52 revealed for the first time IFT trafficking on two parallel lines within the flagellum. Anterograde and retrograde IFT occurs on each of these lines. At the distal end, a large individual anterograde IFT train is converted in several smaller retrograde trains in the space of 3–4 s while remaining on the same side of the axoneme

Elongation of the axoneme and dynamics of intraflagellar transport

International audienceCilia and flagella are essential organelles in most eukaryotes including human beings. In this review, we will discuss the mode of assembly of these complex organelles that depends on a dynamic process called intraflagellar transport or IFT. IFT delivers structural elements at the distal end of the cilium where assembly takes place, thereby allowing the growth of the organelle. We next discuss the different models for control of cilium length and their alterations in ciliopathies, genetic diseases associated to ciliary defects.Les cils et flagelles sont des organites essentiels chez la plupart des eucaryotes, y compris chez l’humain. Dans cette revue, nous abordons le mode d’assemblage de ces organites complexes, qui fait intervenir un processus dynamique dénommé transport intraflagellaire. Le transport intraflagellaire apporte les éléments structuraux au bout distal du cil où a lieu l’assemblage, permettant ainsi la croissance de l’organite. Nous exposons ensuite trois modèles différents de contrôle de la longueur du cil avant de discuter de leur altération lors des ciliopathies, maladies génétiques associées aux défauts ciliaires

Host species dominates over landscape structure in shaping foliar fungal communities

Host species dominates over landscape structure in shaping foliar fungal communities. 10. International symposium on phyllosphere microbiolog

Intraflagellar transport is required for the maintenance of the trypanosome flagellum composition but not its length.

International audienceIntraflagellar transport (IFT) is required for construction of most cilia and flagella. Here, we used electron microscopy, immunofluorescence and live video microscopy to show that IFT is absent or arrested in the mature flagellum of Trypanosoma brucei upon RNA interference (RNAi)-mediated knockdown of IFT88 and IFT140, respectively. Flagella assembled prior to RNAi did not shorten, showing that IFT is not essential for the maintenance of flagella length. Although the ultrastructure of the axoneme was not visibly affected, flagellar beating was strongly reduced and the distribution of several flagellar components was drastically modified. The R subunit of the protein kinase A was no longer concentrated in the flagellum but was largely found in the cell body whereas the kinesin 9B motor was accumulating at the distal tip of the flagellum. In contrast, the distal tip protein FLAM8 was dispersed along the flagellum. This reveals that IFT also functions in maintaining the distribution of some flagellar proteins after construction of the organelle is completed

Critical Activities of Rac1 and Cdc42Hs in Skeletal Myogenesis: Antagonistic Effects of JNK and p38 Pathways

The Rho family of GTP-binding proteins plays a critical role in a variety of cellular processes, including cytoskeletal reorganization and activation of kinases such as p38 and C-jun N-terminal kinase (JNK) MAPKs. We report here that dominant negative forms of Rac1 and Cdc42Hs inhibit the expression of the muscle-specific genes myogenin, troponin T, and myosin heavy chain in L6 and C2 myoblasts. Such inhibition correlates with decreased p38 activity. Active RhoA, RhoG, Rac1, and Cdc42Hs also prevent myoblast-to-myotube transition but affect distinct stages: RhoG, Rac1, and Cdc42Hs inhibit the expression of all muscle-specific genes analyzed, whereas active RhoA potentiates their expression but prevents the myoblast fusion process. We further show by two different approaches that the inhibitory effects of active Rac1 and Cdc42Hs are independent of their morphogenic activities. Rather, myogenesis inhibition is mediated by the JNK pathway, which also leads to a cytoplasmic redistribution of Myf5. We propose that although Rho proteins are required for the commitment of myogenesis, they differentially influence this process, positively for RhoA and Rac1/Cdc42Hs through the activation of the SRF and p38 pathways, respectively, and negatively for Rac1/Cdc42Hs through the activation of the JNK pathway