The skeleton of the staghorn coral Acropora millepora: molecular and structural characterization

15 pagesInternational audienceThe scleractinian coral Acropora millepora is one of the most studied species from the Great Barrier Reef. This species has been used to understand evolutionary, immune and developmental processes in cnidarians. It has also been subject of several ecological studies in order to elucidate reef responses to environmental changes such as temperature rise and ocean acidification (OA). In these contexts, several nucleic acid resources were made available. When combined to a recent proteomic analysis of the coral skeletal organic matrix (SOM), they enabled the identification of several skeletal matrix proteins, making A. millepora into an emerging model for biomineralization studies. Here we describe the skeletal microstructure of A. millepora skeleton, together with a functional and biochemical characterization of its occluded SOM that focuses on the protein and saccharidic moieties. The skeletal matrix proteins show a large range of isoelectric points, compositional patterns and signatures. Besides secreted proteins, there are a significant number of proteins with membrane attachment sites such as transmembrane domains and GPI anchors as well as proteins with integrin binding sites. These features show that the skeletal proteins must have strong adhesion properties in order to function in the calcifying space. Moreover this data suggest a molecular connection between the calcifying epithelium and the skeletal tissue during biocalcification. In terms of sugar moieties, the enrichment of the SOM in arabinose is striking, and the monosaccharide composition exhibits the same signature as that of mucus of acroporid corals. Finally, we observe that the interaction of the acetic acid soluble SOM on the morphology of in vitro grown CaCO3 crystals is very pronounced when compared with the calcifying matrices of some mollusks. In light of these results, we wish to commend Acropora millepora as a model for biocalcification studies in scleractinians, from molecular and structural viewpoints

In vitro and in vivo behavior of coral treated by hydrogen peroxide, supercritical ethanol, or heat

In this study we focus on the use of coral Portites Lutea and the various treatments used to remove proteins while assessing the impact of the various removal methods on the in vitro and in vivo coral behavior. No significant differences were observed between Biocoral(r) and samples treated by either hydrogen peroxide or a thermal procedure. The implants made from supercritical fluid treated coral were more resistant to resorption (50 % more resistant after one month)

Reached multifocal secondary syphilis: A case presentation

International audienceSyphilis is a sexually transmitted infection (STI) related to Treponema pallidum. Secondary syphilis is the blood-borne systemic spread of Treponema.We report the case of secondary syphilis in a patient without risk of STIs factor. The clinical picture began with a genital affection followed by oral erosions and ulcers and an anterior and then posterior uveitis. Serology established the diagnosis and intravenous penicillin G treatment allowed for healing.Called the "great pretender" because of its clinical polymorphism, secondary syphilis can lead to formidable neurological and ophthalmological complications. Serological diagnosis is based on the use of treponemal and a nontreponemal tests. Penicillin G remains the treatment of choice and must be adapted according to the clinical damage