Elaboration and characterization of bioplastic films based on bitter cassava starch (Manihot esculenta) reinforced by chitosan extracted from crab (Shylla seratta) shells

Bioplastics are polymer plastics which are derived from renewable biomass resources. In this study, bioplastic films based on two different polysaccharides such as bitter cassava starch and chitosan extracted from crab shells were produced by casting technique, using glycerol as plasticizer. The purposes of this research are to characterize and to figure out the effect of additional chitosan concentrations (0; 10; 20; 30; 50% by weight of starch) on the physicochemical, mechanical and water barrier properties of bioplastic films. The film's solubility in water (S), water absorption capacity (WAP), water vapor permeability (WVP), tensile strength (TS), elongation at break (E), Young's modulus (YM) and biodegradability were investigated. The possible interactions between starch and chitosan molecules were evaluated by Fourier transform infrared spectroscopy (FTIR). From the analysis, the incorporation of the chitosan shows improved results on the water barrier properties of the bioplastic films. Optimum solubility in water, water absorption capacity, and water vapor permeability are obtained on the composition of starch/chitosan was 50/50. Actually, the addition of chitosan increased tensile strength, and elongation at break. The characterization of optimum mechanical proprieties also occurred on the 50/50 composition of cassava-starch and chitosan. At this ratio, tensile strength obtained were 6,3000 MPa; and the elongation at break were 62,8571%. It was found that cassava-starch/chitosan-based films have a stable structure compared to native cassava-starch films.Comment: 14 pages, 15 figure

Endothelial Secreted Factors Suppress Mitogen Deprivation-Induced Autophagy and Apoptosis in Glioblastoma Stem-Like Cells

International audienceRapidly growing and highly vascularized tumors, such as glioblastoma multiforme, contain heterogeneous areas within the tumor mass, some of which are inefficiently supplied with nutrients and oxygen. While the cell death rate is elevated in such zones, tumor cells are still suspected to grow and survive independently of extracellular growth factors. In line with this, glioblastoma stem-like cells (GSCs) are found closely associated with brain vasculature in situ, and as such are most likely in a protected microenvironment. However, the behavior of GSCs under deprived conditions has not been explored in detail. Using a panel of 14 patient-derived GSCs, we report that ex vivo mitogen deprivation impaired self-renewal capability, abolished constitutive activation of the mTor pathway, and impinged on GSC survival via the engagement of autophagic and apoptotic cascades. Moreover, pharmacological inhibition of the mTor pathway recapitulated the mitogen deprivation scenario. In contrast, blocking either apoptosis or autophagy, or culturing GSCs with endothelial-secreted factors partly restored mTor pathway activation and rescued GSC survival. Overall, our data suggest that GSCs are addicted to mTor, as their survival and self-renewal are profoundly dependent on this signaling axis. Thus, as mTor governs the fate of GSCs under both deprivation conditions and in the presence of endothelial factors, it could be a key target for therapeutic purposes

Un établissement rural gallo-romain à Gellainville " Le Radray " (Eure-et-Loir) (fin du Ier s. av. J.-C.-fin du IVe s. ap. J.-C.)

Le site du " Radray " sur la commune de Gellainville (28) a été fouillé en 2007. L’article présente les principaux résultats de la partie gallo-romaine du site. L’occupation se met en place à partir de la première moitié du Ier s. de notre ère. Dès les dernières décennies avant notre ère s’organise un réseau parcellaire et s’établissent les premiers bâtiments. À partir du milieu du Ier s., l’exploitation agricole se répartit selon deux ensembles : à l’est, la partie résidentielle et les dépendances, à l’ouest, la partie agricole et les bâtiments d’exploitation. L’établissement est abandonné au cours du IIIe s. Les structures du Bas-Empire ne tiennent plus compte des limites précédentes. L’occupation est matérialisée par quelques bâtiments et mares disposés à l’intérieur et en bordure d’un enclos trapézoïdal. Un petit groupe de greniers aériens est installé à l’écart, au sud-ouest. L’abandon systématique des structures d’habitation à partir de 375 ap. J.-C. montre une transformation globale de l’espace.Abstract: The site of "Radray" in the municipality of Gellainville (28) has been excavated in 2007. The article presents the main results of the Gallo-Roman part of the site. The occupation begins from the first half of the first century A.D. During the augustean period, a "parcellaire" system gets organized and the first buildings are established. Since the middle of the first century, the space is organized for the setting up of a rural settlement. On both sides of a rural path, the farming is distribued in two groups: eastwards the residential part and the outbuildings, westwards the agricultural part and the farming buildings. The settlement is abandoned during the third century. The structures of the late antiquity do not follow the former limits. The occupation is materialized by four pouds and some buildings disposed inside und south of a trapezoïdal enclosure. Besides a little group of aerial storehouses is settled apart, towards the south west. The systematic surrender of the habitation structures from 375 A.D. Shows a global transformation of the area

Un établissement rural gallo-romain à Gellainville " Le Radray " (Eure-et-Loir) (fin du Ier s. av. J.-C.-fin du IVe s. ap. J.-C.)

Le site du " Radray " sur la commune de Gellainville (28) a été fouillé en 2007. L’article présente les principaux résultats de la partie gallo-romaine du site. L’occupation se met en place à partir de la première moitié du Ier s. de notre ère. Dès les dernières décennies avant notre ère s’organise un réseau parcellaire et s’établissent les premiers bâtiments. À partir du milieu du Ier s., l’exploitation agricole se répartit selon deux ensembles : à l’est, la partie résidentielle et les dépendances, à l’ouest, la partie agricole et les bâtiments d’exploitation. L’établissement est abandonné au cours du IIIe s. Les structures du Bas-Empire ne tiennent plus compte des limites précédentes. L’occupation est matérialisée par quelques bâtiments et mares disposés à l’intérieur et en bordure d’un enclos trapézoïdal. Un petit groupe de greniers aériens est installé à l’écart, au sud-ouest. L’abandon systématique des structures d’habitation à partir de 375 ap. J.-C. montre une transformation globale de l’espace.Abstract: The site of "Radray" in the municipality of Gellainville (28) has been excavated in 2007. The article presents the main results of the Gallo-Roman part of the site. The occupation begins from the first half of the first century A.D. During the augustean period, a "parcellaire" system gets organized and the first buildings are established. Since the middle of the first century, the space is organized for the setting up of a rural settlement. On both sides of a rural path, the farming is distribued in two groups: eastwards the residential part and the outbuildings, westwards the agricultural part and the farming buildings. The settlement is abandoned during the third century. The structures of the late antiquity do not follow the former limits. The occupation is materialized by four pouds and some buildings disposed inside und south of a trapezoïdal enclosure. Besides a little group of aerial storehouses is settled apart, towards the south west. The systematic surrender of the habitation structures from 375 A.D. Shows a global transformation of the area

Two Contrasting Classes of Nucleolus-Associated Domains in Mouse Fibroblast Heterochromatin [preprint]

In interphase eukaryotic cells, almost all heterochromatin is located adjacent to the nucleolus or to the nuclear lamina, thus defining Nucleolus Associated Domains (NADs) and Lamina Associated Domains (LADs), respectively. Here, we determined the first genome-scale map of murine NADs in mouse embryonic fibroblasts (MEFs) via deep sequencing of chromatin associated with purified nucleoli. We developed a Bioconductor package called NADfinder and demonstrated that it identifies NADs more accurately than other peak-calling tools, due to its critical feature of chromosome-level local baseline correction. We detected two distinct classes of NADs. Type I NADs associate frequently with both the nucleolar periphery and with the nuclear lamina, and generally display characteristics of constitutive heterochromatin, including late DNA replication, enrichment of H3K9me3 and little gene expression. In contrast, Type II NADs associate with nucleoli but do not overlap with LADs. Type II NADs tend to replicate earlier, display greater gene expression, and are more often enriched in H3K27me3 than Type I NADs. The nucleolar associations of both classes of NADs were confirmed via DNA-FISH, which also detected Type I but not Type II probes enriched at the nuclear lamina. Interestingly, Type II NADs are enriched in distinct gene classes, notably factors important for differentiation and development. In keeping with this, we observed that a Type II NAD is developmentally regulated, present in MEFs but not in undifferentiated embryonic stem (ES) cells