Correlated responses in lines of Drosophila melanogaster selected for different oviposition behaviours.

uploaded by Plazi from Taxodro

Using an electrochemical assay to determine the biofilm elasticity change as a response to toxicant exposure

Elasticity is a trait of biofilm physiognomy which relates to cell clustering and can be measured by means of an electrochemical assay based on rotating disc electrode (RDE). This study aimed at testing the hypothesis according to which exposure of phototrophic biofilm to toxicant could reduce its elasticity. We compared biofilms developed for 21 days, in four sets of 6 replicated experimental units, in absence and presence of isoproturon at two concentrations of the inoculating suspension of biofilm, 103 and 104 diatom cell mL-1. Biofilm thickness and elasticity were measured based on RDE assay, bacterial and diatom density were measured by microscope-based numerations.Very thin biofilms (< 10 µm) were obtained as compared with a previous study. This might be linked with the way we selected the initial biofilm providing the suspension and the way we developed its growth. The biofilm elasticity mean values in the presence of isoproturon was quasi twice lower (60 ± 10 and 60 ± 41 µm rpm0.5) than the treatment without isoproturon (138 ± 93 and 115 ± 104 µm rpm0.5), for initial biofilm concentration of 103 and 104 respectively, but there was no significant difference between the mean values of each treatment. Nevertheless, the present preliminary study demonstrated the feasibility of an experiment dedicated to assessing biofilm elasticity changes as a response to toxicant exposure

Life History Response of Mediterranean Fruit Flies to Dietary Restriction

The purpose of this study was to investigate medfly longevity and reproduction across a broad spectrum of diet restriction using a protocol similar to those applied in most rodent studies. Age-specific reproduction and age of death were monitored for 1,200 adult males and 1,200 females, each individually maintained on one of 12 diets from ad libitum to 30% of ad libitum. Diet was provided in a fixed volume of solution that was fully consumed each day, ensuring control of total nutrient consumption for every fly. Contrary to expectation and precedence, increased longevity was not observed at any level of diet restriction. Among females, reproduction continued across all diet levels despite the cost in terms of increased mortality. Among males, life expectancy exceeded that of females at most diet levels. However, in both sexes, mortality increased more sharply and the pattern of survival changed abruptly once the diet level fell to 50% of ad libitum or below, even though the energetic demands of egg production has no obvious counterpart in males. We believe that a more complete picture of the life table response to dietary restriction will emerge when studies are conducted on a wider range of species and include both sexes, more levels of diet, and the opportunity for mating and reproduction

In Vitro Model of Vascularized Bone: Synergizing Vascular Development and Osteogenesis

Tissue engineering provides unique opportunities for regenerating diseased or damaged tissues using cells obtained from tissue biopsies. Tissue engineered grafts can also be used as high fidelity models to probe cellular and molecular interactions underlying developmental processes. In this study, we co-cultured human umbilical vein endothelial cells (HUVECs) and human mesenchymal stem cells (MSCs) under various environmental conditions to elicit synergistic interactions leading to the colocalized development of capillary-like and bone-like tissues. Cells were encapsulated at the 1∶1 ratio in fibrin gel to screen compositions of endothelial growth medium (EGM) and osteogenic medium (OM). It was determined that, to form both tissues, co-cultures should first be supplied with EGM followed by a 1∶1 cocktail of the two media types containing bone morphogenetic protein-2. Subsequent studies of HUVECs and MSCs cultured in decellularized, trabecular bone scaffolds for 6 weeks assessed the effects on tissue construct of both temporal variations in growth-factor availability and addition of fresh cells. The resulting grafts were implanted subcutaneously into nude mice to determine the phenotype stability and functionality of engineered vessels. Two important findings resulted from these studies: (i) vascular development needs to be induced prior to osteogenesis, and (ii) the addition of additional hMSCs at the osteogenic induction stage improves both tissue outcomes, as shown by increased bone volume fraction, osteoid deposition, close proximity of bone proteins to vascular networks, and anastomosis of vascular networks with the host vasculature. Interestingly, these observations compare well with what has been described for native development. We propose that our cultivation system can mimic various aspects of endothelial cell – osteogenic precursor interactions in vivo, and could find utility as a model for studies of heterotypic cellular interactions that couple blood vessel formation with osteogenesis

The role of organisms in hyporheic processes : gaps in current knowledge, needs for future research and applications

Fifty years after the hyporheic zone was first defined (Orghidan, 1959), there are still gaps in the knowledge regarding the role of biodiversity in hyporheic processes. First, some methodological questions remained unanswered regarding the interactions between biodiversity and physical processes, both for the study of habitat characteristics and interactions at different scales. Furthermore, many questions remain to be addressed to help inform our understanding of invertebrate community dynamics, especially regarding the trophic niches of organisms, the functional groups present within sediment, and their temporal changes. Understanding microbial community dynamics would require investigations about their relationship with the physical characteristics of the sediment, their diversity, their relationship with metabolic pathways, their inter- actions with invertebrates, and their response to environmental stress. Another fundamental research question is that of the importance of the hyporheic zone in the global metabolism of the river, which must be explored in relation to organic matter recycling, the effects of disturbances, and the degradation of contaminants. Finally, the application of this knowledge requires the development of methods for the estimation of hydro- logical exchanges, especially for the management of sediment clogging, the optimization of self-purification, and the integration of climate change in environmental policies. The development of descriptors of hyporheic zone health and of new metrology is also crucial to include specific targets in water policies for the long-term management of the system and a clear evaluation of restoration strategies

Bone regeneration and stem cells.

?  Introduction ?  Bone fracture healing and healing problems ?  Biomaterial scaffolds and tissue engineering in bone formation -  Bone tissue engineering -  Biomaterial scaffolds -  Synthetic scaffolds -  Micro- and nanostructural properties of scaffolds -  Conclusion ?  Mesenchymal stem cells and osteogenesis -  Bone tissue -  Origin of osteoblasts -  Isolation and characterization of bone marrow derived MSC -  In vitro differentiation of MSC into osteoblast lineage cells -  In vivo differentiation of MSC into bone -  Factors and pathways controlling osteoblast differentiation of hMSC -  Defining the relationship between osteoblast and adipocyte differentiation from MSC -  MSC and sex hormones -  Effect of aging on osteoblastogenesis -  Conclusion ?  Embryonic, foetal and adult stem cells in osteogenesis -  Cell-based therapies for bone -  Specific features of bone cells needed to be advantageous for clinical use -  Development of therapeutic biological agents -  Clinical application concerns -  Conclusion ?  Platelet-rich plasma (PRP), growth factors and osteogenesis -  PRP effects in vitro on the cells involved in bone repair -  PRP effects on osteoblasts -  PRP effects on osteoclasts -  PRP effects on endothelial cells -  PRP effects in vivo on experimental animals -  The clinical use of PRP for bone repair -  Non-union -  Distraction osteogenesis -  Spinal fusion -  Foot and ankle surgery -  Total knee arthroplasty -  Odontostomatology and maxillofacial surgery -  Conclusion ?  Molecular control of osteogenesis -  TGF-β signalling -  FGF signalling -  IGF signalling -  PDGF signalling -  MAPK signalling pathway -  Wnt signalling pathway -  Hedgehog signalling -  Notch signalling -  Ephrin signalling -  Transcription factors regulating osteoblast differentiation -  Conclusion ?  Summary This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed

Édition de la correspondance de la Mère Angélique Arnauld (1591-1661), abbesse et réformatrice de Port-Royal, avec Louse-Marie de Gonzague (1611-1667), reine de Pologne - 4 tomes, 5 volumes

Bouletreau François. Édition de la correspondance de la Mère Angélique Arnauld (1591-1661), abbesse et réformatrice de Port-Royal, avec Louse-Marie de Gonzague (1611-1667), reine de Pologne - 4 tomes, 5 volumes . In: École pratique des hautes études, Section des sciences religieuses. Annuaire. Tome 90, 1981-1982. 1981. pp. 519-521

Literatura y Antropología: Arawak y Caribes

Los mitos Caribes están estrechamente ligados al mar.&nbsp; Originarios de las mesetas amazónicas del alto Brasil, ese pueblo emigró durante generaciones descendiendo en un primer momento a la Amazonía para esparcirse sobre las costas de Guyana y de Venezuela; algunos fueron después a poblar las costas y el interior profundo de Colombia remontando las arterias fluviales que son el Atrato, el Cauca y el Magdelena. Diversas son las tribus de ese país reportadas por Javier Ocampo-López: "Urubaes, Turbacos, Zenúes, Motilones, Quimbayas, Catíos, Chocoes, Calimas, Pijaos, Panches, Muzos y otros.&nbsp