Amber and the Cretaceous Resinous Interval

Amber is fossilized resin that preserves biological remains in exceptional detail, study of which has revolutionized understanding of past terrestrial organisms and habitats from the Early Cretaceous to the present day. Cretaceous amber outcrops are more abundant in the Northern Hemisphere and during an interval of about 54 million years, from the Barremian to the Campanian. The extensive resin production that generated this remarkable amber record may be attributed to the biology of coniferous resin producers, the growth of resiniferous forests in proximity to transitional sedimentary environments, and the dynamics of climate during the Cretaceous. Here we discuss the set of interrelated abiotic and biotic factors potentially involved in resin production during that time. We name this period of mass resin production by conifers during the late Mesozoic, fundamental as an archive of terrestrial life, the `Cretaceous Resinous Interval (CREI).This work was supported by the Spanish Ministerio de Ciencia, Innovación y Universidades [research agreement CRE CGL2017-84419 AEI/FEDER, UE] and by the Consejería de Industria, Turismo, Innovación, Transporte y Comercio of the Gobierno de Cantabria through the public enterprise EL SOPLAO S.L. [research agreement #20963 with University of Barcelona and research contract Ref. VAPC 20225428 to CN-IGME CSIC, both 2022–2025]; the Conselho Nacional de Pesquisa (Brazil) [research grand PQ 304529/19–2]; National Geographic Global Exploration Fund Northern Europa [research agreement GEFNE 127-14]; Deutsche Forschungsgemeinschaft (DFG) [research agreement SO 894/6-1]; VolkswagenStiftung [research agreement 90946]; the Secretary of Universities and Research (Government of Catalonia) and by the Horizon 2020 program of research and innovation of the European Union under the Marie-Curie [research contract no. 801370, Beatriu de Pinós]; the Secretary of Universities and Research (Government of Catalonia) and the European Social Fund [research contract 2021FI_B2 00003]; this work is a contribution to the grant RYC2021-032907-I, funded by the MCIN/AEI/10.13039/501100011033 and by the European Union «NextGenerationEU»/PRTR; and the National Agency for Research and Development (ANID) Scholarship Program [BECAS CHILE 2020-Folio 72210321].Abstract Keywords 1. Introduction 2. Definition of the Cretaceous Resinous Interval 3. Conditional factors on resin production and preservation 3.1. Abiotic factors 3.1.1. Atmospheric gas composition, temperature, and wildfires 3.1.2. Volcanism and changes in sea level 3.1.3. Oceanic physicochemical properties and hurricanes 3.1.4. Climatic overview throughout the CREI 3.2. Biotic factors 4. Present limitations and future directions 5. Conclusions Funding Author contributions Declaration of Competing Interest Acknowledgements Appendix A. Supplementary data Data availability Reference

Schwann-cell cylinders grown inside hyaluronic-acid tubular scaffolds with gradient porosity

[EN] Cell transplantation therapies in the nervous system are frequently hampered by glial scarring and cell drain from the damaged site, among others. To improve this situation, new biomaterials may be of help. Here, novel single-channel tubular conduits based on hyaluronic acid (HA) with and without poly-l-lactide acid fibers in their lumen were fabricated. Rat Schwann cells were seeded within the conduits and cultured for 10days. The conduits possessed a three-layered porous structure that impeded the leakage of the cells seeded in their interior and made them impervious to cell invasion from the exterior, while allowing free transport of nutrients and other molecules needed for cell survival. The channel's surface acted as a template for the formation of a cylindrical sheath-like tapestry of Schwann cells continuously spanning the whole length of the lumen. Schwann-cell tubes having a diameter of around 0.5mm and variable lengths can thus be generated. This structure is not found in nature and represents a truly engineered tissue, the outcome of the specific cell-material interactions. The conduits might be useful to sustain and protect cells for transplantation, and the biohybrids here described, together with neuronal precursors, might be of help in building bridges across significant distances in the central and peripheral nervous system.The authors acknowledge financing through projects MAT2011-28791-C03-02 and 03, and ERA-NET NEURON project PRI-PIMNEU-2011-1372. We thank the Cytomics Core Facility at Principe Felipe Research Center (CIPF, Valencia, Spain) for their support and advice in flow cytometry experiments, and the Electron Microscopy Service at the UPV, where the SEM images were obtained. The authors thankfully acknowledge the reviewers' comments, which have helped to improve the clarity of the paper's presentation.Vilariño Feltrer, G.; Martínez Ramos, C.; Monleon De La Fuente, A.; Vallés Lluch, A.; Moratal Pérez, D.; Barcia Albacar, JA.; Monleón Pradas, M. (2016). Schwann-cell cylinders grown inside hyaluronic-acid tubular scaffolds with gradient porosity. Acta Biomaterialia. 30:199-211. https://doi.org/10.1016/j.actbio.2015.10.040S1992113