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Eitel M.,Stiftung Tierarztliche Hochschule Hanover | Guidi L.,Life and Environment science | Hadrys H.,Stiftung Tierarztliche Hochschule Hanover | Hadrys H.,Yale University | And 3 more authors.

Unraveling animal life cycles and embryonic development is basic to understanding animal biology and often sheds light on phylogenetic relationships. A key group for understanding the evolution of the Metazoa is the early branching phylum Placozoa, which has attracted rapidly increasing attention. Despite over a hundred years of placozoan research the life cycle of this enigmatic phylum remains unknown. Placozoa are a unique model system for which the nuclear genome was published before the basic biology (i.e. life cycle and development) has been unraveled. Four organismal studies have reported the development of oocytes and one genetic study has nourished the hypothesis of sexual reproduction in natural populations at least in the past. Here we report new observations on sexual reproduction and embryonic development in the Placozoa and support the hypothesis of current sexual reproduction. The regular observation of oocytes and expressed sperm markers provide support that placozoans reproduce sexually in the field. Using whole genome and EST sequences and additional cDNA cloning we identified five conserved sperm markers, characteristic for different stages in spermatogenesis. We also report details on the embryonic development up to a 128-cell stage and new ultrastructural features occurring during early development. These results suggest that sperm and oocyte generation and maturation occur in different placozoans and that clonal lineages reproduce bisexually in addition to the standard mode of vegetative reproduction. The sum of observations is best congruent with the hypothesis of a simple life cycle with an alternation of reproductive modes between bisexual and vegetative reproduction. © 2011 Eitel et al. Source

Garcia-Gallego S.,University of Alcala | Garcia-Gallego S.,CIBER ISCIII | Rodriguez J.S.,Hospital General Universitario Gregorio Maranon | Rodriguez J.S.,CIBER ISCIII | And 10 more authors.
Dalton Transactions

We describe here the synthesis and characterization of new sulfonated and carboxylated-containing N-donor ligands [Na 4(edts)]·4H 2O (2), [Na 2(dmeddp)]·2H 2O (3) and [Na 4(edtp)]·H 2O (4) (edts = ethylene-diamine- N,N,N′,N′-tetraethylenesulfonate ion; dmeddp = dimethyl-ethylene- diamine-N,N,N′,N′-tetra-3-propionate ion; edtp = ethylene-diamine-N,N,N′,N′-tetra-3-propionate ion) and their corresponding metal (Ni, Co, Cu and Zn) complexes. Mainly, UV-Vis and a computer aided analysis of the EPR spectra provided information on the geometry and structure of the complexes in solution. Some of the metal complexes inhibit HIV replication when treating both pre- and post-infected PBMC cells, and hustle the inhibitory effect compared to the metal salts alone. © 2012 The Royal Society of Chemistry. Source

Garcia-Gallego S.,University of Alcala | Garcia-Gallego S.,CIBER ISCIII | Cangiotti M.,Life and Environment science | Fiorani L.,Life and Environment science | And 8 more authors.
Dalton Transactions

Herein we describe the synthesis and characterization of new sulfonated and carboxylated poly(propyleneimino) (PPI) dendrimers with the ethylenediamino (EDA) core, at generations 1, 2 and 3. By means of UV-Vis and EPR spectroscopy, using Cu2+ as a probe, we concluded that these dendrimers show a specific pattern in the coordination of metal ions. In agreement with the UV-Vis studies, EPR spectra of carboxylated compounds are constituted by 3 different signals which appear and then disappear with increasing copper concentration, corresponding to the saturation of different copper complexation sites. At the lowest copper concentration up to a 1:1 molar ratio between CuII and the dendrimer, the spectrum is characteristic of a CuN2O2 coordination at the core of the dendrimer. The spectrum appearing at higher CuII concentrations indicates a peripheral location of the ions coordinating one nitrogen and 3 oxygen atoms in a square planar geometry in restricted mobility conditions. For the highest concentrations tested, copper ions are confined at the external dendrimer surface with CuO4 coordination. For sulfonate systems, the EPR results are in line with a weaker interaction of CuII with the nitrogen sites and a stronger interaction with the oxygen (SO3 -) groups with respect to the interactions measured by EPR for carboxylate systems. © 2013 The Royal Society of Chemistry. Source

Rossi J.-C.,Montpellier University | Maret B.,Montpellier University | Vidot K.,Montpellier University | Francoia J.-P.,Montpellier University | And 4 more authors.
Macromolecular Bioscience

Poly-L-lysine is a biocompatible polymer used for drug or gene delivery, for transport through cellular membranes, and as nanosized magnetic resonance imaging contrast agents. Cu(II)-poly-L-lysine complexes are of particular interest for their role in biocatalysis. In this study, poly-L-lysine dendrigrafts (DGLs) at different generations (G2, G3, and G4) are synthesized and characterized in absence and presence of Cu(II) by means of electron paramagnetic resonance (EPR), UV-Vis, potentiometric titration and circular dichroism (CD). The analysis is performed as a function of the [Cu(II)]/[Lys] (=R) molar ratio, pH and generation by identifying differently flexible complexes in different dendrimer regions. The amine sites in the lateral chains become increasingly involved with the increase of pH. The good agreement and complementarity of the results from the different techniques provide an integrate view of the structural and dynamic properties of Cu(II)-DGL complexes implementing their use as biocatalysts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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