Heterosteginapapyracea Seguenza du Miocène du Corridor Sud-Rifain (Maroc) : biométrie et particularités paléoécologiques

Biometric study of the inner features of Heterostegina specimens preserved in tortonian sediments of the oued Yhoudi member allows to confirm the presence of species Heterostegina papyracea Seguenza, 1880. Analysis of both large and small components of the foraminiferal assemblage in all examined samples establishes the dominant character of species Heterostegina papyracea Seguenza (more than 60% of total benthic foraminifera). The assemblage of small benthic foraminifera associated with the Heterostegina is different from that described from Recent sediments, as well as from Miocene sediments of Calabria and Spain. In order to explain this result, two hypotheses can be put forward: (1) the Tortonian Heterostegina from Morocco proliferated abundantly in very shallow environments in association with small foraminifera (i.e. abundant Ammonia beccarii). (2) Because of powerful tidal currents in the South Rifian Corridor, Heterostegina tests were probably transferred after death. This transfer could possibly be due to the narrowness of the South Rifian Corridor in the Early Late Tortonian and its position between the Atlantic and the Mediterranean. Similar cases foraminiferal displacements are also known from modern basins. This study illustrates the difficulties in reconstructing the paleogeography of the studied area and the importance of considering all available components of the assemblage.     

Biochronologie et corrélation des bassins néogènes du Couloir sud-rifain (Maroc) fondées sur les évènements de foraminifères planctoniques et de nannofossiles calcaires

Qualitative and quantitative analyses of planktonic foraminifera (completed by calcareous nannofossils in some localities) from 8 sections and boreholes located in 7 Neogene basins of the South Rifian Corridor (Morocco) enable us to identify 16 bioevents calibrated with the geomagnetic polarity time scale. These events are useful for (1) assigning the sediments to the Tortonian (bioevents 1 to 7), the Messinian (bioevents 9 to 14, the event 8 indicates the Tortonian/Messinian boundary), the Early Pliocene (bioevent 15) and the Middle Pliocene (bioevent 16), (2) establishing high resolution correlations between the sections and boreholes studied herein, (3) locating the South Rifian Corridor sections and boreholes within the framework of biostratigraphic events recognized during the latest ten years in time-equivalent Atlantic and Mediterranean sequences, and (4) estimating the variation of sedimentation rates in the studied basins. With respect to Morocco, previous detailed studies concerned only the Rabat area (Bou Regreg valley) and Guercif basin. Our results extend correlations to the other basins of the South Rifian Corridor, a key area to understand connections between the Atlantic Ocean and the Mediterranean Sea at the end of the Miocene.     

Distinct motifs of neuropeptide Y receptors differentially regulate trafficking and desensitization

Activated human neuropeptide Y Y(1) receptors rapidly desensitize and internalize through clathrin-coated pits and recycle from early and recycling endosomes, unlike Y(2) receptors that neither internalize nor desensitize. To identify motifs implicated in Y(1) receptor desensitization and trafficking, mutants with varying C-terminal truncations or a substituted Y(2) C-terminus were constructed. Point mutations of key putative residues were made in a C-terminal conserved motif [phi-H-(S/T)-(E/D)-V-(S/T)-X-T] that we have identified and in the second intracellular i2 loop. Receptors were analyzed by functional assays, spectrofluorimetric measurements on living cells, flow cytometry, confocal imaging and bioluminescence resonance energy transfer assays for beta-arrestin activation and adaptor protein (AP-2) complex recruitment. Inhibitory GTP-binding protein-dependent signaling of Y(1) receptors to adenylyl cyclase and desensitization was unaffected by C-terminal truncations or mutations, while C-terminal deletion mutants of 42 and 61 amino acids no longer internalized. Substitutions of Thr357, Asp358, Ser360 and Thr362 by Ala in the C-terminus abolished both internalization and beta-arrestin activation but not desensitization. A Pro145 substitution by His in an i2 consensus motif reported to mediate phosphorylation-independent recruitment of beta-arrestins affected neither desensitization, internalization or recycling kinetics of activated Y(1) receptors nor beta-arrestin activation. Interestingly, combining Pro145 substitution by His and C-terminal substitutions significantly attenuates Y(1) desensitization. In the Y(2) receptor, replacement of His155 with Pro at this position in the i2 loop motif promotes agonist-mediated desensitization, beta-arrestin activation, internalization and recycling. Overall, our results indicate that beta-arrestin-mediated desensitization and internalization of Y(1) and Y(2) receptors are differentially regulated by the C-terminal motif and the i2 loop consensus motif.     

Involvement of actin in agonist-induced endocytosis of the G protein-coupled receptor for thromboxane A2: overcoming of actin disruption by arrestin-3 but not arrestin-2

The role of actin in endocytosis of G protein-coupled receptors is poorly defined. In the present study, we demonstrate that agents that depolymerize (latrunculin B and cytochalasin D) or stabilize (jasplakinolide) the actin cytoskeleton blocked agonist-induced endocytosis of the beta isoform of the thromboxane A(2) receptor (TPbeta) in HEK293 cells. This suggests that endocytosis of TPbeta requires active remodeling of the actin cytoskeleton. On the other hand, disruption of microtubules with colchicine did not affect endocytosis of the receptor. Expression of wild-type and mutant forms of the small GTPases RhoA and Cdc42 potently inhibited endocytosis of TPbeta, further indicating a role for the dynamic regulation of the actin cytoskeleton in this pathway. Agonist treatment of TPbeta in HEK293 cells resulted in the formation of actin stress fibers through Galpha(q/11) signaling. Because we previously showed that endocytosis of TPbeta is dependent on arrestins, we decided to explore the relation between arrestin-2 and -3 and actin in endocytosis of this receptor. Interestingly, we show that the inhibition of TPbeta endocytosis by the actin toxins in HEK293 cells was overcome by the overexpression of arrestin-3, but not of arrestin-2. These results indicate that the actin cytoskeleton is not essential in arrestin-3-mediated endocytosis of TPbeta. However, arrestin-3 could not promote endocytosis of the TPbetaY339A and TPbetaI343A carboxyl-terminal mutants when the actin cytoskeleton was disrupted. Our data provide new evidence that the actin cytoskeleton plays an essential role in TPbeta endocytosis. Furthermore, our work suggests the existence of actin-dependent and -independent arrestin-mediated pathways of endocytosis.     

Esthesioneuroblastoma metastatic to the breast in a young woman

BACKGROUND: Metastases to the breast are rare and can be missed without knowledge of the clinical history. We report an unusual breast metastasis originating in an olfactory neuroblastoma. CASE: A breast metastasis from esthesioneuroblastoma occurred in a 20-year-old woman 2 years after the onset of the disease. The aspirates were hypercellular and composed of cellular aggregates and single cells with a monomorphic appearance. The cytoplasm was scanty and inconspicuous. The nucleus was large, with granular, hyperchromatic chromatin. Mitoses and apoptotic bodies were numerous. Because we were unaware of the past history at the time of the cytologic analysis, a definitive diagnosis was made only after pathologic study. CONCLUSION: Esthesioneuroblastoma metastatic to the breast must be considered in the differential diagnosis of breast metastases. Fine needle aspiration, in conjunction with clinical information, can be effective in the diagnosis of esthesioneuroblastoma metastatic to the breast.     

Science-policy interfaces for biodiversity: dynamic learning environments for successful impact

To address the pressing problems associated with biodiversity loss, changes in awareness and behaviour are required from decision makers in all sectors. Science-policy interfaces (SPIs) have the potential to play an important role, and to achieve this effectively, there is a need to understand better the ways in which existing SPIs strive for effective communication, learning and behavioural change. Using a series of test cases across the world, we assess a range of features influencing the effectiveness of SPIs through communication and argumentation processes, engagement of actors and other aspects that contribute to potential success. Our results demonstrate the importance of dynamic and iterative processes of interaction to support effective SPI work. We stress the importance of seeing SPIs as dynamic learning environments and we provide recommendations for how they can enhance success in meeting their targeted outcomes. In particular, we recommend building long-term trust, creating learning environments, fostering participation and ownership of the process and building capacity to combat silo thinking. Processes to enable these changes may include, for example, inviting and integrating feedback, extended peer review and attention to contextualising knowledge for different audiences, and time and sustained effort dedicated to trust-building and developing common languages. However there are no ‘one size fits all’ solutions, and methods must be adapted to context and participants. Creating and maintaining effective dynamic learning environments will both require and encourage changes in institutional and individual behaviours: a challenging agenda, but one with potential for positive feedbacks to maintain momentum.     

Correlation between the Chemical and Genetic Relationships among Thymus saturejoides Genotypes Cultured under in vitro and in vivo Environments

In this study, the in vitro and in vivo essential oil (EO) composition and genetic variability in six micropropagated genotypes of Thymus saturejoides Coss ., a Mediterranean medicinal and aromatic plant, were analyzed by GC/MS and randomly amplified polymorphic DNA (RAPD). Yield and composition of the EO varied between genotypes. Cluster analysis based on RAPD data and EO grouped the six genotypes in three groups in both culture conditions, thus showing considerable intraspecific genetic and chemical variations. Applying the Mantel test, the result showed a significant correlation between the two proximity matrices RAPD and EO obtained from in vitro genotypes, whereas this correlation was not observed when using the EO obtained from the in vivo genotypes.     

Toxicological Study and Oxidative Stress Evaluation for Safety Assessment of Xylanase Preparations in Wistar Rats

Acute and 90‐day subchronic oral toxicity studies were conducted to establish the safety evaluation of xylanases preparations. A potential oxidative stress evaluation was also performed through testing the generation of oxidative radicals, depletion of antioxidants via oxidative modification of lipids, proteins and DNA of organ cells. During the subchronic oral toxicity study, no mortality was observed, obvious treatment‐related clinical signs and urinalysis parameters were in normal range. Differences in some hematological parameters, biochemistry, relative organ weight, and histopathology examinations between the treated group and the control group were not judged to be adverse. Our results indicated that the no‐observed‐adverse‐effect level for xylanases was 1,500 TXU/kg/day and the plasma antioxidant assays showed that these xylanases did not produce free‐radicals nor oxidative injuries. On the basis of the bacterial reverse mutation assay data, it is concluded that the expressed xylanase in Pichia pastoris do not present any mutagenic potential when tested in relevant genotoxicological assays.     

Detection of WWE2-related Lentisphaerae by 16S rRNA gene sequencing and fluorescence in situ hybridization in landfill leachate

We collected samples of anaerobic landfill leachate from municipal solid waste landfill (Vert-le-Grand, France) and constructed 16S rRNA clone libraries using primers targeting Planctomycetes and relatives (Pla46F and 1390R). Analyses of 16S rRNA gene sequences resulted in the abundant representation of WWE2-related Lentisphaerae, members of the phylum Lentisphaerae, in the clone library (98% of the retrieved sequences). Although the sequences that are phylogenetically affiliated with the cultured isolate Victivallis vadensis were identified (WWE2 subgroup II), the majority of the sequences were affiliated with an uncultured Lentisphaerae lineage (WWE2 subgroup I). We designed oligonucleotides probes targeting the specific 16S rRNA gene regions of those 2 subgroups. Fluorescence in situ hybridization confirmed the abundance of the uncultivated WWE2 subgroup I in our leachate samples.