Reconstitution de gestes funéraires

Lors de fouilles archéologiques de sépultures, il est rare de retrouver les restes d’un linceul, surtout sous un climat tempéré. En revanche, le climat très sec de Nubie explique la conservation exceptionnelle de la matière organique (peau, cheveux, muscle, fécès…) sur l’ensemble des nécropoles de l’île de Saï. Dans une tombe probablement de l’époque chrétienne (postérieure à la culture ballanéenne – appelée aussi Groupe X – et antérieure à la conquête ottomane) de la grande nécropole nord (SN), la fouille a mis au jour un jeune sujet entièrement enveloppé d’un linceul. Cela nous a permis de reconstituer une partie des gestes qui ont accompagné l’inhumation de cet enfant. À la suite de cette étude, nous pouvons avancer l’hypothèse que le linceul a été conçu pour faciliter une position spécifique du corps lors de son dépôt dans la tombe. Il avait donc une grande importance en ce qui concerne la position finale du cadavre.In a temperate environment, during the excavation of burials, it is very rare to find the remains of shroud pieces. At the opposite, the very dry climate of the Middle Nubia can explain by itself the exceptional conservation of soft parts of the human body (hair, nails, brain, muscular fibres, human coprolithes) as it is frequently found at the North necropolis (SN) of the Saï island (Northern Province, Sudan). In a post X-group and ante-Muslim burial (T. 176), the excavation has allowed the discovery of a very young individual still wrapped in a shroud. It has been possible to reconstruct the shape of the shroud, the way in which it was wrapped and fixed around the body. This has allowed us to present the hypothesis that the shape of the shroud and the way to attach it have had a voluntary influence in the final position of the child in the pit, i. e. a dorsal decubitus of the body with the head hyper-flexed on the top of the trunk. Then, even if one side of the tissue of the shroud has been tear without care, its final shape is voluntary and implies a well defined funeral practice for such a child. In a Nubian archaeological context, such a practice is described for the first time —for the post X Group period in Sudan— at the Saï Island. Moreover, the limited extension of the excavated archaeological surface of this necropolis has allowed the discovery of other individuals (adults, juveniles) with important and also well preserved pieces of tissues or shrouds. Then, the taphonomical as well as the paleobiological potentialities of this necropolis seem to be very important

Neutral-ionic phase transition : a thorough ab-initio study of TTF-CA

The prototype compound for the neutral-ionic phase transition, namely TTF-CA, is theoretically investigated by first-principles density functional theory calculations. The study is based on three neutron diffraction structures collected at 40, 90 and 300 K (Le Cointe et al., Phys. Rev. B 51, 3374 (1995)). By means of a topological analysis of the total charge densities, we provide a very precise picture of intra and inter-chain interactions. Moreover, our calculations reveal that the thermal lattice contraction reduces the indirect band gap of this organic semi-conductor in the neutral phase, and nearly closes it in the vicinity of the transition temperature. A possible mechanism of the neutral-ionic phase transition is discussed. The charge transfer from TTF to CA is also derived by using three different technics.Comment: 11 pages, 9 figures, 7 table

ruvA Mutants that resolve Holliday junctions but do not reverse replication forks

RuvAB and RuvABC complexes catalyze branch migration and resolution of Holliday junctions (HJs) respectively. In addition to their action in the last steps of homologous recombination, they process HJs made by replication fork reversal, a reaction which occurs at inactivated replication forks by the annealing of blocked leading and lagging strand ends. RuvAB was recently proposed to bind replication forks and directly catalyze their conversion into HJs. We report here the isolation and characterization of two separation-of-function ruvA mutants that resolve HJs, based on their capacity to promote conjugational recombination and recombinational repair of UV and mitomycin C lesions, but have lost the capacity to reverse forks. In vivo and in vitro evidence indicate that the ruvA mutations affect DNA binding and the stimulation of RuvB helicase activity. This work shows that RuvA's actions at forks and at HJs can be genetically separated, and that RuvA mutants compromised for fork reversal remain fully capable of homologous recombination

Steinert's syndrome presenting as anal incontinence: a case report

<p>Abstract</p> <p>Introduction</p> <p>Myotonic dystrophy (MD) or Steinert's syndrome is a rare cause of chronic diarrhea and anal incontinence. In the presence of chronic diarrhea and fecal incontinence with muscle weakness, neuromuscular disorders such as myotonic dystrophy should be considered in the differential diagnosis.</p> <p>Case Presentation</p> <p>We present the case of a 45-year-old Turkish man with Steinert's syndrome, who was not diagnosed until the age of 45.</p> <p>Conclusions</p> <p>In clinical practice, the persistence of diarrhea and fecal incontinence with muscle weakness should suggest that the physician perform an anal manometric study and electromyography. Neuromuscular disorders such as myotonic dystrophy should be considered in the differential diagnosis.</p

RecG interacts directly with SSB: implications for stalled replication fork regression

RecG and RuvAB are proposed to act at stalled DNA replication forks to facilitate replication restart. To define the roles of these proteins in fork regression, we used a combination of assays to determine whether RecG, RuvAB or both are capable of acting at a stalled fork. The results show that RecG binds to the C-terminus of single-stranded DNA binding protein (SSB) forming a stoichiometric complex of 2 RecG monomers per SSB tetramer. This binding occurs in solution and to SSB protein bound to single stranded DNA (ssDNA). The result of this binding is stabilization of the interaction of RecG with ssDNA. In contrast, RuvAB does not bind to SSB. Side-by-side analysis of the catalytic efficiency of the ATPase activity of each enzyme revealed that (−)scDNA and ssDNA are potent stimulators of the ATPase activity of RecG but not for RuvAB, whereas relaxed circular DNA is a poor cofactor for RecG but an excellent one for RuvAB. Collectively, these data suggest that the timing of repair protein access to the DNA at stalled forks is determined by the nature of the DNA available at the fork. We propose that RecG acts first, with RuvAB acting either after RecG or in a separate pathway following protein-independent fork regression

Irradiation-Induced Deinococcus radiodurans Genome Fragmentation Triggers Transposition of a Single Resident Insertion Sequence

Stress-induced transposition is an attractive notion since it is potentially important in creating diversity to facilitate adaptation of the host to severe environmental conditions. One common major stress is radiation-induced DNA damage. Deinococcus radiodurans has an exceptional ability to withstand the lethal effects of DNA–damaging agents (ionizing radiation, UV light, and desiccation). High radiation levels result in genome fragmentation and reassembly in a process which generates significant amounts of single-stranded DNA. This capacity of D. radiodurans to withstand irradiation raises important questions concerning its response to radiation-induced mutagenic lesions. A recent study analyzed the mutational profile in the thyA gene following irradiation. The majority of thyA mutants resulted from transposition of one particular Insertion Sequence (IS), ISDra2, of the many different ISs in the D. radiodurans genome. ISDra2 is a member of a newly recognised class of ISs, the IS200/IS605 family of insertion sequences

Neuronal Chemokines: Versatile Messengers In Central Nervous System Cell Interaction

Whereas chemokines are well known for their ability to induce cell migration, only recently it became evident that chemokines also control a variety of other cell functions and are versatile messengers in the interaction between a diversity of cell types. In the central nervous system (CNS), chemokines are generally found under both physiological and pathological conditions. Whereas many reports describe chemokine expression in astrocytes and microglia and their role in the migration of leukocytes into the CNS, only few studies describe chemokine expression in neurons. Nevertheless, the expression of neuronal chemokines and the corresponding chemokine receptors in CNS cells under physiological and pathological conditions indicates that neuronal chemokines contribute to CNS cell interaction. In this study, we review recent studies describing neuronal chemokine expression and discuss potential roles of neuronal chemokines in neuron–astrocyte, neuron–microglia, and neuron–neuron interaction

Genome-wide association analyses identify new Brugada syndrome risk loci and highlight a new mechanism of sodium channel regulation in disease susceptibility

Brugada syndrome (BrS) is a cardiac arrhythmia disorder associated with sudden death in young adults. With the exception of SCN5A, encoding the cardiac sodium channel NaV1.5, susceptibility genes remain largely unknown. Here we performed a genome-wide association meta-analysis comprising 2,820 unrelated cases with BrS and 10,001 controls, and identified 21 association signals at 12 loci (10 new). Single nucleotide polymorphism (SNP)-heritability estimates indicate a strong polygenic influence. Polygenic risk score analyses based on the 21 susceptibility variants demonstrate varying cumulative contribution of common risk alleles among different patient subgroups, as well as genetic associations with cardiac electrical traits and disorders in the general population. The predominance of cardiac transcription factor loci indicates that transcriptional regulation is a key feature of BrS pathogenesis. Furthermore, functional studies conducted on MAPRE2, encoding the microtubule plus-end binding protein EB2, point to microtubule-related trafficking effects on NaV1.5 expression as a new underlying molecular mechanism. Taken together, these findings broaden our understanding of the genetic architecture of BrS and provide new insights into its molecular underpinnings