Project description:A metabarcoding study of the microbial communities in the corallivorous Coralliophila meyendorffii (Muricidae, Coralliophilinae) and its venomous coral host Parazoanthus axinellae (Zoanthidea, Parazoanthidae).
Project description:Ultra-high pressure liquid chromatography coupled to high resolution mass spectrometry (UHPLC-MS/MS) analysis of the organic extract obtained from the Mediterranean zoanthid Parazoanthus axinellae yielded to the identification of five new parazoanthines F-J. The structures were fully determined by comparison of fragmentation patterns with those of previously isolated parazoathines and MS/MS spectra simulation of in silico predicted compounds according to the metabolome consistency. The absolute configuration of the new compounds has been assigned using on-line electronic circular dichroism (UHPLC-ECD). We thus demonstrated the potential of highly sensitive hyphenated techniques to characterize the structures of a whole family of natural products within the metabolome of a marine species. Minor compounds can be characterized using these techniques thus avoiding long isolation processes that may alter the structure of the natural products. These results are also of interest to identify putative bioactive compounds present at low concentration in a complex mixture.
Project description:Coralligenous assemblages are among the most species-rich and vulnerable habitats of the Mediterranean Sea. Nevertheless, data on connectivity patterns on species inhabiting these habitats, crucial to define management and protection priorities, are largely lacking. Moreover, unreliable species-level taxonomy can confound ecological studies and mislead management strategies. In the northwestern Mediterranean two Parazoanthus axinellae morphotypes differing in size, color and preferred substrate are found in sympatry. In this study, we used COI and ITS sequence polymorphism to assess (1) the genetic divergence between the two morphotypes, (2) their connectivity patterns and (3) their phylogenetic position within the Parazoanthidae. Specimens of P. axinellae were sampled in 11 locations along the northwestern Mediterranean; in 6 locations, samples of the two morphotypes were collected in sympatry. Small genetic diversity and structure were found within morphotypes, while marked and consistent differentiation was detected between them. Moreover, the less widespread morphotype appeared to be closer to Pacific species as P. juanfernandezii and P. elongatus. Our findings confirmed the limited knowledge on Parazoanthus species complex, and how this gap can have important implication for the conservation strategies of this widespread and valuable genus in the Mediterranean Sea.
Project description:Metabolomics has recently proven its usefulness as complementary tool to traditional morphological and genetic analyses for the classification of marine invertebrates. Among the metabolite-rich cnidarian order Zoantharia, Parazoanthus is a polyphyletic genus whose systematics and phylogeny remain controversial. Within this genus, one of the most studied species, Parazoanthus axinellae is prominent in rocky shallow waters of the Mediterranean Sea and the NE Atlantic Ocean. Although different morphotypes can easily be distinguished, only one species is recognized to date. Here, a metabolomic profiling approach has been used to assess the chemical diversity of two main Mediterranean morphotypes, the "slender" and "stocky" forms of P. axinellae. Targeted profiling of their major secondary metabolites revealed a significant chemical divergence between the morphotypes. While zoanthoxanthin alkaloids and ecdysteroids are abundant in both morphs, the "slender" morphotype is characterized by the presence of additional and bioactive 3,5-disubstituted hydantoin derivatives named parazoanthines. The absence of these specific compounds in the "stocky" morphotype was confirmed by spatial and temporal monitoring over an annual cycle. Moreover, specimens of the "slender" morphotype are also the only ones found as epibionts of several sponge species, particularly Cymbaxinella damicornis thus suggesting a putative ecological link.