Aim The Indo-Pacific is the world's largest marine biogeographic region. It is characterised by different degrees of connectivity among its subregions and harbours the majority of demosponge species currently known to science. Comparisons between regional sponge faunas have been undertaken in the past, mostly based on morphological species identification. The Sponge Barcoding Project, in tandem with regional DNA taxonomy campaigns, provides one of the largest DNA-based taxonomic data collections from sponges of the Indo-Pacific. Here, we utilise the barcoding data in the most extensive molecular biodiversity study of sponges to date, which reveals patterns of shallow-water demosponge faunal connectivity, endemism and distribution in the Indo-Pacific with a level of resolution unavailable in prior morphology-based studies.Location Demosponge specimens in this study cover 13 marine provinces (MPs) of the Indo-Pacific.Methods We classified demosponge barcodes from 1910 sponge samples into 701 molecular operational taxonomic units (MOTUs) using 28S rRNA. MOTU composition of the MPs was compared based on Jaccard and S & oslash;renson dissimilarities and other biodiversity indices.Results Our data corroborated high endemism in MPs (up to 84.1% endemic MOTUs). Faunal overlaps are between the Red Sea and the Gulf, which displayed small connectivity with other MPs in the Western Indian Ocean. The Western Indian Ocean is a strong faunistic boundary to the Central Indo-Pacific, to which the Polynesian sponge faunas were comparatively isolated as well.Main Conclusions Our data corroborate case studies on sponges that generally reject the presence of cosmopolitan or otherwise widespread sponge species, instead revealing high levels of regional endemism. This is consistent with similar observations and hypotheses in other marine invertebrates, and highlights the need for close regional monitoring to identify biodiversity changes. Connectivity among Indo-Pacific MPs differs for demosponges in many aspects from that of other marine taxa, hypothetically due to their shorter pelagic larval phase.

Dynamics of microbiomes through time are fundamental regarding survival and resilience of their hosts when facing environmental alterations. As for marine species with commercial applications, such as marine sponges, assessing the temporal change of prokaryotic communities allows us to better consider the adaptation of sponges to aquaculture designs. The present study aims to investigate the factors shaping the microbiome of the sponge Dactylospongia metachromia, in a context of aquaculture development in French Polynesia, Rangiroa, Tuamotu archipelago. A temporal approach targeting explants collected during farming trials revealed a relative high stability of the prokaryotic diversity, meanwhile a complementary biogeographical study confirmed a spatial specificity amongst samples at different longitudinal scales. Results from this additional spatial analysis confirmed that differences in prokaryotic communities might first be explained by environmental changes (mainly temperature and salinity), while no significant effect of the host phylogeny was observed. The core community of D. metachromia is thus characterized by a high spatiotemporal constancy, which is a good prospect for the sustainable exploitation of this species towards drug development. Indeed, a microbiome stability across locations and throughout the farming process, as evidenced by our results, should go against a negative influence of sponge translocation during in situ aquaculture.

The present study examines the taxonomy of sponge specimens with unique chemistry collectively known as Fascaplysinopsis reticulata (Hentschel, 1912). Examination of Hentschel’s original species upon which the genus Fascaplysinopsis Bergquist, 1980 was based in conjunction with a comparison with recent Indo-west Pacific collections, using morphological and molecular analyses (ITS and 28S rDNA), revealed extensive variation. Fascaplysinopsis reticulata was found to be a species complex comprising the genus Fascaplysinopsis, as well as two new genera: Skolosachlys gen. nov. and Rubrafasciculus gen. nov. The new species of Fascaplysinopsis described are F. palauensis sp. nov., F. klobos sp. nov. and F. ronquinni sp. nov. The new species of Skolosachlys gen. nov. described herein are: S. enlutea sp. nov. and S. nidus sp. nov. The new species described of Rubrafasciculus gen. nov. includes: R. cerasus sp. nov. and R. fijiensis sp. nov..

The distribution of marine sponges in the tropical Southwest Pacific Ocean is largely unexplored despite the vital ecological role of sponges in coral reefs and their value as sources of metabolites for drug design. Several collection campaigns to the French Polynesian archipelagos (Society, Marquesas, Tuamotu, Gambier, and Austral) were conducted to assess the bio- and chemodiversity of the island groups. In the course of these scientific expeditions, more than 200 identified sponge specimens were acquired, for which we were able to assign 102 Molecular Operational Taxonomic Units (MOTUs). Based on these MOTUs, we assessed, in the largest analysis of its kind for this area to date, the sponge composition and faunistic overlaps of the marine province Southeast Polynesia with Marquesas and Central Polynesia. We also compared the sponge fauna of these Eastern Indo-Pacific provinces with marine provinces of the adjacent Central Indo-Pacific realm. Our findings corroborate that sponge faunal similarity within marine realms is higher than among realms, and follows the marine barriers to gene flow observed for other taxa. We detected high levels of provincial endemism for marine sponges, consistent with findings from other Indo-Pacific regions. At the level of province, geographical distance and ocean surface currents influence faunal similarity, and constitute the primary factors for the connectivity of sponge faunas between the disjunct and remote island groups in the tropical Southwest Pacific Ocean.

Marine sponges have a long history of farming, starting with bath sponges over 5000 years ago in the Mediterranean. Many species have since been found appropriate for distinct types of commercial assessment. Drug development relies on the isolation of sponge-derived secondary metabolites as natural compounds having a wide range of ecological functions, from deterring predation to preventing microbial infection/proliferation on the sponge body. For human society, they feature a broad array of pharmacological properties with some applications still being discovered. Their limited supply has however been faced as a major obstacle to the conduct of clinical trials. Marine aquaculture has to prove more integrated and sustainable to remain an interesting way to ensure sufficient amounts of biological substances for the early processing and production of drugs. This review presents sponge farming methods that were tested, the undergoing challenges they faced and the interest they raised on environmental and metabolic factors to explain contrasting spatiotemporal performances. Through global experiments, sometimes involving other marine organisms, technicity of sponge aquaculture has long been evolving to ensure efficient and cost-effective strategies. Further ways to make sponge farming more attractive and diversify its commercial applications are investigated, such as recent studies in collagen or chitin production for bone tissue engineering or bioremediation as an alternative to existing wastewater management. Overall, marine sponges exhibit astonishing intra and interspecific variation, which is why they should be considered with respect to the purpose of their economic valuation, their environmental context and all the symbiotic interactions they rely on.

Lithistid demosponges are well known from limestone caves of karstic origin in the Mediterranean Sea. However, they have never been reported from submarine caves of volcanic origin in the South Pacific. Here, we describe and provide DNA barcodes for four new lithistid demosponges including one new genus. All species grew on basaltic rocks inside lava tubes on Nuku Hiva Island (Marquesas Islands) and Tahiti Iti peninsula on Tahiti Island (Society Islands) in French Polynesia. Three of the species have rhizoclone desmas as choanosomal skeletons and belong to the family Scleritodermidae (Microscleroderma miritatarata sp. nov. and Microscleroderma lava sp. nov.) and Siphonidiidae (Gastrophanella basaltica sp. nov.). The new genus Levispongia gen. nov. belongs to the family Corallistidae. The new species Levispongia meyeri gen. nov. sp. nov. has dicranoclone desmas, complex dichotrianes with strongly spinose upper surfaces of the cladome and microstyles as the only microscleres. Phylogenetic relationships of these new species are discussed and compared with other material from the Caribbean and Central to the West Pacific Ocean. urn:lsid:zoobank.org:pub:844E385C-9A92-4F1B-B85C-9C1E319CD13F

Chemical investigation of the South-Pacific marine sponge Suberea clavata led to the isolation of eight new bromotyrosine metabolites named subereins 1–8 (2–9) along with twelve known co-isolated congeners. The detailed configuration determination of the first representative major compound of this family 11-epi-fistularin-3 (11R,17S) (1) is described. Their chemical characterization was achieved by HRMS and integrated 1D and 2D NMR (nuclear magnetic resonance) spectroscopic studies and extensive comparison with literature data. For the first time, a complete assignment of the absolute configurations for stereogenic centers C-11/17 of the known members (11R,17S) 11-epi-fistularin-3 (1) and 17-deoxyfistularin-3 (10) was determined by a combination of chemical modifications, Mosher’s technology, and ECD spectroscopy. Consequently, the absolute configurations of all our new isolated compounds 2–9 were determined by the combination of NMR, Mosher’s method, ECD comparison, and chemical modifications. Interestingly, compounds 2–7 were obtained by chemical transformation of the major compound 11-epi-fistularin-3 (1). Evaluation for acetylcholinesterase inhibition (AChE), DNA methyltransferase 1 (DNMT1) modulating activity and antifouling activities using marine bacterial strains are also presented.

Four new brominated tyrosine metabolites, aplyzanzines C–F (1–4), were isolated from the French Polynesian sponge Pseudoceratina n. sp., along with the two known 2-aminoimidazolic derivatives, purealidin A (5) and 6, previously isolated, respectively, from the sponges Psammaplysilla purpurea and Verongula sp. Their structures were assigned based on the interpretation of their NMR and HRMS data. The compounds exhibited quorum sensing inhibition (QSi) and antifouling activities against several strains of bacteria and microalgae. To our knowledge, the QSi activity of this type of bromotyrosine metabolite is described here for the first time.

Although the French Polynesian reefs are among the most well studied reefs of the world, sponges are still poorly known, with only 199 species or OTUs of sponges having been described from French Polynesia, 167 at an OTU level and 32 at a species level. From those 199 species, just five are calcareous sponges. As it is possible that this number is underestimated, the aim of the present work was to study the diversity of calcareous sponges from French Polynesia. Hence, different French Polynesian archipelagos were surveyed by SCUBA from 3 to 60 m of depth. Identifications were performed using morphological and molecular (ITS and C-LSU) tools. We found a total of nine species of Calcarea, comprising five different genera. Five species are new to science: Clathrina fakaravae sp. nov., Clathrina huahineae sp. nov., Ernstia variabilis sp. nov., Leucascus digitiformis sp. nov., and Leucandra tahuatae sp. nov. With the present work, the number of identified sponges from French Polynesia at a species level increased from 32 to 41. The only calcareous sponge previously known from French Polynesia that was recollected by our group was Leucetta chagosensis. Our results suggest that the Eastern Indo-Pacific Realm shows more affinity with the Central and the Western Indo-Pacific Realms. Four species supported these affinities: Ascandra cf. crewsi, previously known only from Papua New Guinea, Leucascus simplex from South Australia, and Leucetta chagosensis and L. microraphis, both widespread species in the Indo-Pacific. These two Leucetta species, however, most likely represent species complexes. Once again the molecular markers ITS and C-LSU helped in the identification of calcareous sponges, showing how important is an integrative taxonomy. Although our work has increased in 250% (6 spp to 15 spp) the diversity of calcareous sponges in French Polynesia, it is most possible that this number is still underestimated.

Marine natural products isolated from the sponge Fascaplysinopsis cf reticulata, in French Polynesia, were investigated as an alternative to antibiotics to control pathogens in aquaculture. The overuse of antibiotics in aquaculture is largely considered to be an environmental pollution, because it supports the transfer of antibiotic resistance genes within the aquatic environment. One environmentally friendly alternative to antibiotics is the use of quorum sensing inhibitors (QSIs). Quorum sensing (QS) is a regulatory mechanism in bacteria which control virulence factors through the secretion of autoinducers (AIs), such as acyl-homoserine lactone (AHL) in gram-negative bacteria. Vibrio harveyi QS is controlled through three parallel pathways: HAI-1, AI-2, and CAI-1. Bioassay-guided purification of F. cf reticulata extract was conducted on two bacterial species, i.e., Tenacibaculum maritimum and V. harveyi for antibiotic and QS inhibition bioactivities. Toxicity bioassay of fractions was also evaluated on the freshwater fish Poecilia reticulata and the marine fish Acanthurus triostegus. Cyclohexanic and dichloromethane fractions of F. cf reticulata exhibited QS inhibition on V. harveyi and antibiotic bioactivities on V. harveyi and T. maritimum, respectively. Palauolide (1) and fascaplysin (2) were purified as major molecules from the cyclohexanic and dichloromethane fractions, respectively. Palauolide inhibited QS of V. harveyi through HAI-1 QS pathway at 50 μg ml–1 (26 μM), while fascaplysin affected the bacterial growth of V. harveyi (50 μg ml–1) and T. maritimum (0.25 μg). The toxicity of fascaplysin-enriched fraction (FEF) was evaluated and exhibited a toxic effect against fish at 50 μg ml–1. This study demonstrated for the first time the QSI potential of palauolide (1). Future research may assess the toxicity of both the cyclohexanic fraction of the sponge and palauolide (1) on fish, to confirm their potential as alternative to antibiotics in fish farming.

We report herein a ring-distortion strategy applied to marine natural substances ilimaquinone and 5-epi-ilimaquinone. A chemically diverse library of molecules was synthesised that included rearrangements of the sesquiterpene moiety and original reorganisations of the quinone ring. Chemoinformatic analyses evaluated the rise of structural diversity and the exploration of chemical space. Some focussed biological activities of this library were also investigated; quorum sensing activity of Vibrio harveyi was envisaged and some of the new compounds were shown to be good quorum sensing inhibitor candidates, whereas others were activators. Toxicities were also evaluated and some products showed micromolar activities against human umbilical vein endothelium, human hepatocellular carcinoma and human lung carcinoma (A549) cells.

The Cover Feature shows a ring-distortion strategy applied to the marine natural product ilimaquinone. A chemically diverse library of molecules was synthesised that included rearrangements of the sesquiterpene moiety and original reorganisations of the quinone ring. Compounds were evaluated as quorum sensing inhibitors of Vibrio Harveyi, an economically important pathogen in French Polynesia. This work is depicted in a festive theme for the special issue celebrating the 20th anniversary of the journal. More information can be found in the Full Paper by L. Evanno, E. Poupon et al.

Treatment of acute myeloid leukemia (AML) patients is still hindered by resistance and relapse, resulting in an overall poor survival rate. Recently, combining specific B-cell lymphoma (Bcl)-2 inhibitors with compounds downregulating myeloid cell leukemia (Mcl)-1 has been proposed as a new effective strategy to eradicate resistant AML cells. We show here that 1(R), 6(S), 1'(R), 6'(S), 11(R), 17(S)-fistularin-3, a bromotyrosine compound of the fistularin family, isolated from the marine sponge Suberea clavata, synergizes with Bcl-2 inhibitor ABT-199 to efficiently kill Mcl-1/Bcl-2-positive AML cell lines, associated with Mcl-1 downregulation and endoplasmic reticulum stress induction. The absolute configuration of carbons 11 and 17 of the fistularin-3 stereoisomer was fully resolved in this study for the first time, showing that the fistularin we isolated from the marine sponge Subarea clavata is in fact the (+)-11(R), 17(S)-fistularin-3 stereoisomer keeping the known configuration 1(R), 6(S), 1'(R), and 6'(S) for the verongidoic acid part. Docking studies and in vitro assays confirm the potential of this family of molecules to inhibit DNA methyltransferase 1 activity.

Arsenicin A (C3H6As4O3) was isolated from the New Caledonian poecilosclerid sponge Echinochalina bargibanti, and described as the first natural organic polyarsenic compound. Further bioguided fractionation of the extracts of this sponge led us to isolate the first sulfur-containing organic polyarsenicals ever found in Nature. These metabolites, called arsenicin B and arsenicin C, are built on a noradamantane-type framework that is characterized by an unusual As–As bonding. Extensive NMR measurements, in combination with mass spectra, enabled the assignment of the structure for arsenicin B (C3H6As4S2) as 2. The scarcity of arsenicin C and its intrinsic chemical instability only allowed the collection of partial spectral data, which prevented the full structural definition. After the extensive computational testing of several putative structures, structure 3 was inferred for arsenicin C (C3H6As4OS) by comparing the experimental and density functional theory (DFT)-calculated 1H and 13C NMR spectra. Finally, the absolute configurations of 2 and 3 were determined with a combined use of experimental and time-dependent (TD)-DFT calculated electronic circular dichroism (ECD) spectra and observed specific rotations. These findings pose great challenges for the investigation of the biosynthesis of these metabolites and the cycle of arsenic in Nature. Arsenicins B and C showed strong antimicrobial activities, especially against S. aureus, which is comparable to the reference compound gentamycin.

Herein, we describe the isolation and spectroscopic identification of eight new tetrabrominated tyrosine alkaloids 2–9 from the Polynesian sponge Suberea ianthelliformis, along with known major compound psammaplysene D (1), N,N-dimethyldibromotyramine, 5-hydroxy xanthenuric acid, and xanthenuric acid. Cytotoxicity and acetylcholinesterase inhibition activities were evaluated for some of the isolated metabolites. They exhibited moderate antiproliferative activity against KB cancer cell lines, but psammaplysene D (1) displayed substantial cytotoxicity as well as acetylcholinesterase inhibition with IC50 values of 0.7 μM and 1.3 μM, respectively.

A new species of Raspailia (Raspaxilla) frondosa sp. nov. is described from the deep seamounts of the Norfolk and New Caledonia Ridges. The morphology of the species resembles that of a frond or a fern, and its unique highly compressed axial skeleton of interlaced spongin fibres without spicules in combination with a radial extra axial skeleton of a perpendicular palisade of spicules, differentiate it from all other species of the subgenus. This species is compared morphologically to all 18 other valid species described in Raspailia (Raspaxilla).

Two new acyclic bis-guanidine alkaloids, unguiculins B-C (2-3), were isolated from a French Polynesian sponge Monanchora n. sp. together with the known compound unguiculin A (1). Their structures were established by spectroscopic data interpretation and comparison with the literature. Unguiculins A-C displayed antiproliferative and cytotoxic efficacy against several human cancer cells with IC50 values in the micromolar range.

Dactylospongia metachromia and Dactylospongia elegans collected from French Polynesia were studied with a particular focus on the variation of the diastereomeric ratio between ilimaquinone (4) and 5-epi-ilimaquinone (5). More than 100 samples, covering an area of 4100 km2, were studied to try to clarify this intriguing issue. Nuclear magnetic resonance appeared as the non-destructive, straightforward technique of choice for a relative quantitative study. A random distribution, unique at that point in nature, is observed and leads to biosynthetic considerations. Biological evaluation of both compounds was also performed and showed moderate discrepancies in cytotoxicity and apoptosis induction.

Two sporothriolide-related compounds were obtained from an extract of the fungus Hypoxylon monticulosum CLL-205, isolated from a Sphaerocladina sponge collected from the Tahiti coast. Compound 2 is a deoxy analogue of sporothric acid (4). Compound 3 is a newly reported unusual scaffold combining sporothriolide (1) and trienylfuranol A (5) moieties, through a Diels-Alderase-type reaction. Various experimental and analytical arguments supported the biocatalytic origin of compound 3. The structures of the isolated compounds were elucidated using 1D and 2D NMR, HRMS, and IR data. The structure and the absolute configuration of 3 were unambiguously confirmed by a single-crystal X-ray diffraction analysis.