Echinodermes (Homalozoa: Cornuta et Mitrata) nouveaux pour l'Ordovicien du Massif Armoricain et conséquences paléogéographiques

Two specific genera of Bohemian Llanvirn(Sarka Formation), Reticulocarpos and Lagynocystis have been recognized in Traveusot, le Pissot and Pierre Melière Formations (Llanvirn and Llandeilo of the Armorican Massif). Though three species are new (R. pissotensis, R. sp., Lagynocystis sp.) this discovery once more underlines the relationships between Bohemia and Armorican Massif during this period.     

The susceptibility of weathered versus unweathered schist to biological colonization in the Côa Valley Archaeological Park (north‐east Portugal)

This study addresses the primary and secondary bioreceptivity of schist used as a support for prehistoric rock art in the Côa Valley Archaeological Park (north‐east Portugal) and provides some parameters that can be related to the risk of biologically induced schist weathering. Samples of freshly quarried and naturally weathered schist were characterized in terms of their intrinsic properties and maintained in controlled environmental conditions after inoculation with biofilm‐forming cyanobacteria. The physical properties of the studied schist, as well as its abrasion pH, all varied according to the weathering degree of the samples and so did its susceptibility to colonization by biofilm‐forming cyanobacteria. Complete separation between weathered and unweathered schist samples in terms of laboratory‐induced photosynthetic biomass was obtained by measuring total colour change in the CIE (International Commission on Illumination) L*a*b* colour space. Weathered schist was more bioreceptive than unweathered schist, associated with increased open porosity, water saturation, capillary water and capillarity coefficient and decreased abrasion pH. In the future, it might be possible to determine the susceptibility of schist surfaces to biological colonization through evaluation of colour differences associated with the different weathering degrees presented by those surfaces prior to colonization.     

Purification of a Protease Inhibitor from Hevea brasiliensis cell suspension and it’s effect on the growth of Phytophthora palmivora

Protease inhibitors (PIs) are one family of pathogenesis-related proteins (PR-proteins) that play essential roles in defense mechanisms against an attack by a pathogenic microorganism or insect. Cell suspension derived from a seed integument of rubber tree (Hevea brasiliensis) treated for 48 h with 20 μM copper sulphate, an abiotic elicitor, had an increased production of PIs. The intracellular PIs were detected in an extract of treated cells; however, much higher levels of PIs were found in the medium (extracellular). Using azocasein as substrate, these PIs possessed strong inhibitory activity against subtilisin A but not against trypsin, chymotrysin and papain. These extracellular PIs were purified by anion exchange chromatography, DEAE-Sepharose (CL-6B), eluted with 0.06 M NaCl in 20 mM Tris-HCl (pH 7.0). The active fractions were then subjected to native and SDS preparative gel electrophoresis, respectively. A single band of a purified PI with a molecular weight of 25 kDa was revealed after a tricine SDS-PAGE and stained with silver nitrate. The yield of this purified protein was 3.14 ng.g^?1. The activity of the purified PI was stable up to 70 °C, and its activity was retained in the buffer pH values of 2–10. The biological activity of the obtained PI was investigated. It was found that the PI at 5 μg.mL^?1 (0.2 μM) inhibited the mycelium growth of Phytophthora palmivora, a rubber tree pathogen.