Aquaporins (AQPs) are a family of membrane channels facilitating diffusion of water and small solutes into and out of cells. Despite their biological relevance in osmoregulation and ubiquitous distribution throughout metazoans, the presence of AQPs in annelids has been poorly investigated. Here, we searched and annotated Aqp sequences in public genomes and transcriptomes of annelids, inferred their evolutionary relationships through phylogenetic analyses and discussed their putative physiological relevance. We identified a total of 401 Aqp sequences in 27 annelid species, including 367 sequences previously unrecognized as Aqps. Similar to vertebrates, phylogenetic tree reconstructions clustered these annelid Aqps in four clades: AQP1-like, AQP3-like, AQP8-like and AQP11-like. We found no clear indication of the existence of paralogs exclusive to annelids; however, several gene duplications seem to have occurred in the ancestors of some Sedentaria annelid families, mainly in the AQP1-like clade. Three of the six Aqps annotated in Alitta succinea, an estuarine annelid showing high salinity tolerance, were validated by RT-PCR sequencing, and their similarity to human AQPs was investigated at the level of \"key\" conserved residues and predicted three-dimensional structure. Our results suggest a diversification of the structures and functions of AQPs in Annelida comparable to that observed in other taxa.

The bioavailability of trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn) in lowly to moderately contaminated coastal sediments from the Berre lagoon, France, was assessed by comparing their potentially bioavailable concentrations and bioaccumulated concentrations in the polychaete Alitta succinea. No linear correlations were observed contrarily to what is generally observed in similar works in areas with highly contaminated sediment. Correlations between trace and major elements (Fe, Ca, S, Mg, P, Al) in Alitta succinea tissues and their distribution in organism tissues show that, in such lowly to moderately contaminated sediments, biological variabilities should be considered. Normalization procedures allow to take into account these variabilities and to identify that sediment contamination is partly involved in the benthic ecosystem degradation of the Berre lagoon. Alitta succinea cannot be used as relevant bioindicator for Zn and Co bioavailability in sediment, since these elements are regulated by this organism.

A novel Gram-stain-negative, rod-shaped, motile, non-spore-forming, facultatively anaerobic marine bacterium was isolated from the gastrointestinal tract of the sandworm Alitta succinea collected from Grice Cove, South Carolina, USA. The strain was arginine dihydrolase-positive, and oxidase- and catalase-positive. Growth occurred between 10 and 37 °C, with optimal growth occurring between 30 and 32 °C. Comparative 16S rRNA gene sequence analysis showed its nearest neighbours are members of the genus Kistimonas of the family Hahellaceae, which is found in the order Oceanospirillales, class Gammaproteobacteria. The closest related species was Kistimonas asteriae KMD 001T with 16S rRNA gene sequence similarity of 99.0 %. However, DNA-DNA hybridization between these strains revealed less than 70 % DNA-DNA relatedness, supporting the novel species status of the strain. The major fatty acids were C16 : 0, C18 : 0, C18 : 1ω7c and a summed feature that contained C16 : 1ω6c/C16 : 1ω7c. The major respiratory quinone was ubiquinone-9 and the predominant polar lipids were phosphatidylserine, phosphoethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The genomic DNA G+C content was 52.5 mol%. Based on the data presented, strain BGP-2T is considered to represent a novel member of the genus Kistimonas, for which the name Kistimonas alittae sp. nov. is proposed. The type strain is BGP-2T (=CCUG 65711T=JCM 30010T).