Molecular characterization reveals the complexity of previously overlooked coral-exosymbiont interactions and the implications for coral-guild ecology.

Several obligate associate crabs and shrimps species may co-occur and interact within a single coral host, leading to patterns of associations that can provide essential ecological services. However, knowledge of the dynamics of interactions in this system is limited, partly because identifying species involved in the network remains challenging. In this study, we assessed the diversity of the decapods involved in exosymbiotic assemblages for juvenile and adult Pocillopora damicornis types α and ß on reefs of New Caledonia and Reunion Island. This approach revealed complex patterns of association at regional and local scales with a prevalence of assemblages involving crab-shrimp partnerships. Furthermore, the distinction of two lineages in the snapping shrimp Alpheus lottini complex, rarely recognized in ecological studies, reveals a key role for cryptic diversity in structuring communities of mutualists. The existence of partnerships between species that occurred more commonly than expected by chance suggests an increased advantage for the host or a better adaptation of associated species to local environmental conditions. The consideration of cryptic diversity helps to accurately describe the complexity of interaction webs for diverse systems such as coral reefs, as well as the functional roles of dominant associated species for the persistence of coral populations.

Complexation of the interferon inducer, bropirimine, with hydroxypropyl-beta-cyclodextrin.

Bropirimine (ABPP) is an orally active immunomodulator that increases endogenous alpha-interferon and other cytokines used clinically against carcinoma in situ of the bladder. The oral absorption of ABPP is poor because its low solubility in water. The purpose of this study is to develop a technological procedure useful to increase the water solubility of ABPP. To this end, the interaction of ABPP with several cyclodextrin derivatives-alpha-, beta-, gamma- and hydroxypropyl-beta-cyclodextrin with a degree of substitution 2.7 (HPbetaCD) was studied and the effect of the complexation process on the water solubility of the drug was evaluated. The best results were obtained with the hydroxypropyl derivative, HPbetaCD, that interacts in a 1:1 drug:cyclodextrin molar ratio. The inclusion complex ABPP-HPbetaCD was characterized in solution by nuclear magnetic resonance (1H-NMR). The solid inclusion complex was obtained by freeze-drying and characterized by differential scanning calorimetry (DSC), X-ray diffractometry and mass spectrometry. The dissolution rate of ABPP from the HPbetaCD solid inclusion complex was increased compared to the powdered drug but not differences were found between the complex and a physical mixture with a similar molar ratio. The increase of the dissolution rate of the drug can be attributed to the breakdown in solution of the drug dimers in the presence of the cyclodextrin and to the complex formation.

Spatial patterns and recruitment processes of coral assemblages among contrasting environmental conditions in the southwestern lagoon of New Caledonia.

We investigated the spatial distribution of adult and juvenile coral assemblages in the southwestern lagoon of New Caledonia, from disturbed fringing reefs within bays, to oceanic barrier reefs. Generic richness, abundance, and percent cover were highly variable at this scale, but no clear cross-shelf gradient was found. Rather, community composition was more related to reef biotopes. Correlations and canonical correspondence analyses revealed that composition and abundance of coral assemblages were related to substrate types (cover of turf algae and cover of encrusting coralline algae), but not to water quality or metal concentrations in sediments. We found a strong relationship between juvenile and adult distribution for all dominant genera, which suggests that recruitment processes are also a major factor structuring these populations. The densities of juveniles and their proportion in the coral assemblages were relatively low, which implies that replenishment capacities and potential for recovery are probably limited for these reefs.