Multiple Changes in Peptide and Lipid Expression Associated with Regeneration in the Nervous System of the Medicinal Leech

peer reviewe

BIOLEACHING OF COBALT AND ZINC FROM PYRITE ORE IN RELATION TO CALCITIC GANGUE CONTENT

Bioleaching of a pyrite ore containing high concentrations of cobalt (0.1%) and zinc (0.065%) was affected by small amounts of calcitic gangue (from 0.01 to 1.01%). Results from an air-lift percolator and from Erlenmeyer flask experiments show that a small percentage of calcite raises the pH and arrests the growth of the acidophilic bacterium Thiobacillus ferrooxidans. In percolator experiments, when calcite is completely removed by the continuous addition of small quantities of acid, and the pH of the liquor becomes acid, the micro-organism begins to grow and to bio-oxidize the pyrite ore. The growth of T. ferrooxidans shows different lag phase spans (from 13 to 190 days) depending on carbonate dissolution. The metals Fe, Zn and Co are released into the leaching solution together at different rates after a lag-time which depends on calcite concentrations in pyrite gangue. Metal ratios in the mineral bulk are different from those in the liquor, Zn dissolving 5 times more readily than Co. Bioleaching rates for metal removal from pyrite are higher in percolator (for Fe, from 5 to 15 mg/l/h) than in flask experiments (from 0.5 to 2 mg/l/h), but the lag phases are shorter (from 2 to 65 days). The differences between the two systems are related to calcite dissolution and gypsum precipitation

Polychaetes as annelid models to study ecoimmunology of marine organisms

International audienc

Hm-MyD88 and Hm-SARM: Two key regulators of the neuroimmune system and neural repair in the medicinal leech

International audienceUnlike mammals, the CNS of the medicinal leech can regenerate damaged neurites, thus restoring neural functions after lesion. We previously demonstrated that the injured leech nerve cord is able to mount an immune response promoting the regenerative processes. Indeed neurons and microglia express sensing receptors like Hm-TLR1, a leech TLR ortholog, associated with chemokine release in response to a septic challenge or lesion. To gain insights into the TLR signaling pathways involved during these neuroimmune responses, members of the MyD88 family were investigated. In the present study, we report the characterization of Hm-MyD88 and Hm-SARM. The expression of their encoding gene was strongly regulated in leech CNS not only upon immune challenge but also during CNS repair, suggesting their involvement in both processes. This work also showed for the first time that differentiated neurons of the CNS could respond to LPS through a MyD88-dependent signalling pathway, while in mammals, studies describing the direct effect of LPS on neurons and the outcomes of such treatment are scarce and controversial. In the present study, we established that this PAMP induced the relocalization of Hm-TLR1 and Hm-MyD88 in isolated neurons. I nnate immunity corresponds to the first line of defense common to all metazoans. To sense invading pathogens , animals align a panel of germline-encoded receptors called pattern recognition receptors (PRRs) 1. Among them, the family of TLRs is the best characterized. TLRs are transmembrane proteins containing a Leucine-Rich Repeat (LRR) domain and a cytoplasmic Toll/Il1 receptor (TIR) domain. They detect and distinguish pathogen-associated molecular patterns (PAMPs) derived from various microbial pathogens including viruses, bacteria, protozoa and fungi 2. The recognition of these PAMPs triggers the associated signaling pathways to activate downstream immune responses and eliminate invading pathogens 3. Among the molecules recruited by activated TLRs are the members of the MyD88 family 4. In mammals, it includes 5 adaptor proteins containing a TIR domain: myeloid differentiation factor 88 (MyD88), MyD88-adapter-like (Mal), TIR-domain-containing adaptor protein-inducing IFN beta (TRIF), TRIF-related adaptor molecule (TRAM) and sterile alpha and amardillo-motif-containing protein (SARM). All TLRs, except TLR3, recruit MyD88 to mediate innate immune signaling. MyD88 exhibits an N-terminal death domain (DD) and a C-terminal TIR domain. Upon stimulation of TLRs, MyD88 interacts with the cytosolic part of TLR through a homophilic interaction of the TIR domains. Its DD, in turn, associates with the DD of interleukin-1 receptor associated kinase (IRAK) to trigger downstream signaling cascades that lead to the activation of NF-kB 5–7. The structure of MyD88 is extremely well conserved across evolution and its key role in immunity has been demonstrated in both bilaterian and non bilaterian species 8–14. The second member of the MyD88 family particularly well conserved throughout the animal kingdom is SARM. Indeed, it is the only TIR domain-containing adaptor conserved from C. elegans to mammals 15,1

Getting around Antarctica: new high-resolution mappings of the grounded and freely-floating boundaries of the Antarctic ice sheet created for the International Polar Year.

The boundary of grounded ice and the location of ice transitioning to a freely floating state are mapped at 15-m resolution around the entire continent of Antarctica. These data products are produced by participants of the International Polar Year project ASAID using customized software combining Landsat-7 imagery and ICESat laser altimetry. The grounded ice boundary is 53 610 km long; 74% of it abuts to floating ice shelves or outlet glaciers, 19% is adjacent to open or sea-ice covered ocean, and 7% of the boundary are land terminations with bare rock. Elevations along each line are selected from 6 candidate digital elevation models: two created from the input ICESat laser altimetry and Landsat data, two from stereo satellite imagery, and two from compilations of primarily radar altimetry. Elevation selection and an assignment of confidence in the elevation value are based on agreement with ICESat elevation values and shape of the surface inferred from the Landsat imagery. Elevations along the freely-floating boundary (called the hydrostatic line) are converted to ice thicknesses by applying a firn-correction factor and a flotation criterion. The relationship between the seaward offset of the hydrostatic line from the grounding line only weakly matches a prediction based on beam theory. Airborne data are used to validate the technique of grounding line mapping, elevation selection and ice thickness derivation. The mapped products along with the customized software to generate them and a variety of intermediate products are available from the National Snow and Ice Data Center

Cancer and life-history traits : lessons from host-parasite interactions

Despite important differences between infectious diseases and cancers, tumour development (neoplasia) can nonetheless be closely compared to infectious disease because of the similarity of their effects on the body. On this basis, we predict that many of the life-history (LH) responses observed in the context of host-parasite interactions should also be relevant in the context of cancer. Parasites are thought to affect LH traits of their hosts because of strong selective pressures like direct and indirect mortality effects favouring, for example, early maturation and reproduction. Cancer can similarly also affect LH traits by imposing direct costs and/or indirectly by triggering plastic adjustments and evolutionary responses. Here, we discuss how and why a LH focus is a potentially productive but under-exploited research direction for cancer research, by focusing our attention on similarities between infectious disease and cancer with respect to their effects on LH traits and their evolution. We raise the possibility that LH adjustments can occur in response to cancer via maternal/paternal effects and that these changes can be heritable to (adaptively) modify the LH traits of their offspring. We conclude that LH adjustments can potentially influence the transgenerational persistence of inherited oncogenic mutations in populations