Neopetromin, a Cyclic Tripeptide with a C-N Cross-Link, from the Marine Sponge Neopetrosia sp., That Causes Vacuole Fragmentation in Tobacco BY-2 Cells.

HPLC-MS analysis revealed the presence of an unreported peptide in the extract of the marine sponge Neopetrosia sp. Its structure was determined as a tripeptide, named neopetromin (1), composed of two tyrosine and one tryptophan residues with a heteroaromatic C-N cross-link between side chains. The absolute configuration of amino acids was determined using Marfey's method after ozonolysis and hydrolysis of 1. Compound 1 promoted vacuole fragmentation in an actin-independent manner in tobacco BY-2 cells.

Aaptocarbamates A-G, chlorinated terpene carbamates with antiosteoclastogenic activities from the marine sponge Aaptos sp.

Six undescribed chlorinated sesquiterpene carbamates, aaptocarbamates A-F, and a chlorinated tris-norsesquiterpene carbamate, aaptocarbamate G, were isolated from the marine sponge Aaptos sp. collected in Indonesia. Aaptocarbamates D-F and G possess tetrahydrofurans and a tetrahydrofuranone, respectively. The relative configurations of the tetrahydrofuran units were determined by the NOE correlations and DFT-based calculation of the 13C chemical shifts. This is the first time that chlorinated terpene carbamates have been reported from natural sources. Various aaptamine derivatives have been reported from the Aaptos sponges so far, the isolation of chlorinated terpene carbamates is very rare. Aaptocarbamates A, B, and D showed 60% inhibition of the RANKL-induced formation of multinucleated osteoclasts in RAW264 macrophages at 20 µM.

New lithistid sponge of the genus Sollasipelta (Porifera, Demospongiae,Tetractinellida, Neopeltidae) from submarine caves of the Ryukyu Islands,southwestern Japan, with redescription of S. sollasi.

A new species of 'lithistid' (rock sponge) Sollasipelta subterranea sp. nov. is described from near-shore submarine caves of Okinawa and Shimoji Islands, the Ryukyu Islands, southwestern Japan. This new species is characterized by the smooth dentate ectosomal pseudophyllotriaenes, slender choanosomal oxea/style/subtylostyles and two types of amphiasters, one of which is in two size classes. Sollasipelta subterranea sp. nov. is morphologically closest to Sollasipelta sollasi (Lévi & Lévi, 1989), known from the Philippines deep sea, and our examination of the type specimen of S. sollasi revealed that the pseudophyllotriaenes and desmas are substantially different between the two species, and both species possess two types of amphiasters, one of which has two size classes. Sollasipelta cavernicola (Vacelet & Vasseur, 1965) and S. punctata (Lévi & Lévi, 1983) are transferred to the genus Daedalopelta Sollas, 1888, based on possession of one type of amphiastes as microscleres. Sollasipelta mixta (Vacelet, Vasseur and Lévi, 1976) is formally transferred to the genus Neopelta Schmidt, 1880, based on the morphological characters. A key to species of the genus Sollasipelta Van Soest & Hooper, 2020 is also provided. Sollasipelta subterranea sp. nov. represents the first 'lithistid' sponge from submarine caves of the Western Pacific and the first species of sponge inhabiting anchialine cave environments in the Indo-West Pacific. This is also a new record of the family Neopeltidae from Japanese waters.

A new hexactinellid-sponge-associated zoantharian (Porifera, Hexasterophora) from the northwestern Pacific Ocean.

Symbiotic associations between zoantharians and sponges can be divided into two groups: those that associate with Demospongiae and those that associate with Hexactinellida. Parachurabanashinseimaruae Kise, gen. nov. et sp. nov., a new genus and a new species of Hexactinellida-associated zoantharian from Japanese waters, is described. It is characterized by a combination of the following: i) its host hexactinellid sponge, ii) very flat polyps, iii) cteniform endodermal marginal muscles, and iv) characteristic mutations in three mitochondrial regions (including a unique 26-bp deletion in 16S ribosomal DNA) and three nuclear regions. Parachurabanashinseimaruae Kise, gen. nov. et sp. nov. is the third genus in the family Parazoanthidae that is reported to be associated with Hexasterophora sponges. Although specimens have so far only been collected on Takuyo-Daigo Seamount off Minami-Torishima Island in Japan, unidentified zoantharians of similar description have been reported from the waters around Australia, indicating that the species might be widespread across the Pacific.

Cyclopsammocinamides A and B, Enantiomeric Cyclic Peptides of Cyclocinamide A, from the Marine Sponge Psammocinia sp.

LC-MS and molecular networking analyses of the extract of the marine sponge Psammocinia sp. indicated the presence of two new compounds with multiple halogens. LC-MS-guided isolation yielded cyclic peptides, cyclopsammocinamides A (1) and B (2), in an enantiomeric relationship to cyclocinamide A (3). Planar structures of 1 and 2 were elucidated by NMR and mass spectroscopic analyses and the absolute configurations of the amino acid residues were determined using Marfey's method with their acid hydrolysates. The sponge extract exhibited cytotoxicity and the bioassay-guided isolation afforded a dimeric dilactone macrolide, swinholide A, as the cytotoxic compound.

Single-cell metabolite detection and genomics reveals uncultivated talented producer.

The production of bioactive metabolites is increasingly recognized as an important function of host-associated bacteria. An example is defensive symbiosis that might account for much of the chemical richness of marine invertebrates including sponges (Porifera), 1 of the oldest metazoans. However, most bacterial members of sponge microbiomes have not been cultivated or sequenced, and therefore, remain unrecognized. Unequivocally linking metabolic functions to a cellular source in sponge microbiomes is, therefore, a challenge. Here, we report an analysis pipeline of microfluidic encapsulation, Raman microscopy, and integrated digital genomics (MERMAID) for an efficient identification of uncultivated producers. We applied this method to the chemically rich bacteriosponge (sponge that hosts a rich bacterial community) Theonella swinhoei, previously shown to contain 'Entotheonella' symbionts that produce most of the bioactive substances isolated from the sponge. As an exception, the antifungal aurantosides had remained unassigned to a source. Raman-guided single-bacterial analysis and sequencing revealed a cryptic, distinct multiproducer, 'Candidatus Poriflexus aureus' from a new Chloroflexi lineage as the aurantoside producer. Its exceptionally large genome contains numerous biosynthetic loci and suggested an even higher chemical richness of this sponge than previously appreciated. This study highlights the importance of complementary technologies to uncover microbiome functions, reveals remarkable parallels between distantly related symbionts of the same host, and adds functional support for diverse chemically prolific lineages being present in microbial dark matter.

Amakusamine from a Psammocinia sp. Sponge: Isolation, Synthesis, and SAR Study on the Inhibition of RANKL-Induced Formation of Multinuclear Osteoclasts.

A simple methylenedioxy dibromoindole alkaloid, amakusamine (1), was isolated from a marine sponge of the genus Psammocinia, and its structure was determined from spectroscopic data, time-dependent density-functional theory calculations, and synthesis. Compound 1 inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-induced formation of multinuclear osteoclasts with an IC50 value of 10.5 µM in RAW264 cells. The structure-activity relationship of 1 was also investigated with synthetic derivatives.

Neopetrosidines A-D, pyridine alkaloids isolated from the marine sponge Neopetrosia chaliniformis and their cell cycle elongation activity.

Natural products that inhibit cell cycle progression show promise as anticancer agents and chemical probes. In our research on biologically active natural products that affect cell cycle progression of HeLa/fluorescent ubiquitination-based cell cycle indicator (Fucci)2 cells, the extract of the marine sponge Neopetrosia chaliniformis was revealed to inhibit cell proliferation. Purification of the extract afforded four new pyridine alkaloids, neopetrosidines A-D (1-4). Their structures were elucidated by the interpretation of spectroscopic data and chemical degradation. Compounds 1-4 were found to inhibit cell proliferation of HeLa/Fucci2 cells, and time-lapse imaging showed that 1 exerts its effect by increasing the duration of the cell cycle. Furthermore, we show that 1 perturbs bioenergetics to exhibit a cytostatic effect by reducing the mitochondrial membrane potential.

Halichonic Acid B, a Rearranged Nitrogenous Bisabolene-Type Sesquiterpene from a Marine Sponge Axinyssa sp.

A new rearranged nitrogenous bisabolone-type sesquiterpene, halichonic acid B (1), was isolated from a marine sponge Axinyssa sp. together with halichonic acid (2) and (6R,7S)-7-amino-7,8-dihydro-α-bisabolene (3). The structure of 1 was determined by extensive NMR and MS analyses, revealing an unprecedented carbon framework, and its absolute configuration was elucidated by time-dependent density-functional theory (TDDFT)-based electronic circular dichroism (ECD) spectrum calculation. We propose that 1 and 2 may be biosynthesized in the same pathway, involving the reaction between farnesyl pyrophosphate and glycine, followed by cyclization.

Homophymamide A, Heterodetic Cyclic Tetrapeptide from a Homophymia sp. Marine Sponge: A Cautionary Note on Configurational Assignment of Peptides That Contain a Ureido Linkage.

A previously unreported heterodetic cyclic peptide, homophymamide A (1), was isolated from a Homophymia sp. marine sponge. The structure of homophymamide A was determined to be a lower homologue of anabaenopeptins by spectroscopic analysis, chemical degradation, and chemical synthesis. Analysis of the acidic hydrolysate showed that the racemization of Lys took place, leading us to pose a cautionary note on the configurational assignment of peptides that contain a ureido bond.

Structure Elucidation of Calyxoside B, a Bipolar Sphingolipid from a Marine Sponge Cladocroce sp. through the Use of Beckmann Rearrangement.

Marine sponges are an excellent source of biologically active secondary metabolites. We focus on deep-sea sponges for our discovery study. A marine sponge Cladocroce sp. exhibited cytotoxic activity in the bioactivity screening. From this sponge a previously unreported cytotoxic glycosphingolipid, calyxoside B, was isolated and the structure of this compound was elucidated by analyses of MS and NMR spectra and chemical derivatization. We converted the ketone in the middle of a long aliphatic chain into an oxime to which was applied Beckmann rearrangement to afford two positional isomers of amides. The products were subjected to acidic hydrolysis followed by LC-MS analysis, permitting us to assign unequivocally the position of the ketone. Calyxoside B shows cytotoxicity against HeLa cells with an IC50 value of 31 µM and also weakly stimulated the production of cytokines in mice.

Oshimalides A and B, Sesterterpenes of the Manoalide Class from a Luffariella sp. Deep-Sea Marine Sponge: Application of Asymmetric Dihydroxylation in Structure Elucidation.

Oshimalides A (1) and B (2) were isolated from a Luffariella sp. marine sponge. The absolute configurations of the stereogenic centers in the cyclohexenone ring were determined by the modified Mosher's analysis of the reduction product. The absolute configuration of the stereogenic center in the dihydropyran ring was assigned by analysis of the 1H NMR data of the vicinal diols which were prepared by AD-mix reagents stereoselectively.

Myrindole A, an Antimicrobial Bis-indole from a Marine Sponge Myrmekioderma sp.

Myrindole A, a bis-indole alkaloid, was isolated from the deep-sea sponge Myrmekioderma sp. The high degree of unsaturation of the molecule complicated the assignment of its structure by standard 2D-NMR experiments but was ultimately achieved by a combination of 1H-15N-HMBC and 1,n-ADEQUATE experiments as well as the comparison of measured and calculated CD spectra. Myrindole A showed antimicrobial activity against Gram-positive and Gram-negative bacteria.

Fluorescent image-based high-content screening of extracts of natural resources for cell cycle inhibitors and identification of a new sesquiterpene quinone from the sponge, Dactylospongia metachromia.

Natural products are important sources for drug development. Discovery of natural products that inhibit cell cycle progression significantly contributes to the progress of cancer biology and the development of new antitumor agents. In this study, cell cycle inhibitory activity was evaluated with our extract library of natural resources, including marine invertebrates, fungi, and bacteria, using HeLa/Fucci2 cells which allow classification of the cell cycle phases of living cells. Screening of the extract library revealed that the extract of the marine sponge Dactylospongia metachromia inhibited cell cycle progression at S/G2/M phases. Bioassay-guided fractionation afforded a new sesquiterpene quinone, neoisosmenospongine (1), and four known compounds, nakijiquinone I, N, and Q (2-4) and (-)-dictyoceratin-C (5). The chemical structure of 1 was elucidated by interpretating the NMR and mass spectroscopic data, and the absolute configuration was determined by comparison of the experimental and calculated ECD spectra. Fluorescent imaging of HeLa/Fucci2 cells revealed that 1-4 inhibited the cell cycle progression at S/G2/M phases. This study demonstrated that fluorescent image-based high-content screening using HeLa/Fucci2 cells is an effective approach for isolating cell cycle inhibitors from natural resources.

First record of the genus Discorhabdella (Porifera, Demospongiae, Poecilosclerida, Crambeidae) from Sagami Bay, Japan with description of two new species.

Two new species of Discorhabdella are described from Sagami Bay, Japan. Discorhabdella has been suggested to have an ancient Tethyan origin according to discovery of their unique pseudoastrose acanthostyles from late Eocene to Oligocene deposits. This is the first record of the genus from the northwest Pacific and first record of the family Crambeidae from Japan. Discorhabdellahispida sp. nov. is distinctive within the genus by possession of special sigmoid microscleres and C-shaped isochelae with short alae. Discorhabdellamisakiensis sp. nov. is characterized by short choanosomal subtylostyles, and their length overlapped with that of the ectosomal subtylostyles. Only one other species, Discorhabdellatuberosocapitata (Topsent, 1890), has the same spicule composition. However, all spicule types are larger in D.tuberosocapitata than those of D.misakiensis sp. nov., and the shape of the isochelae is different: the alae are more widely opened in D.tuberosocapitata. An identification key to species of the genus Discorhabdella is also provided. The discovery of two new species from warm temperate northwest Pacific extends the geographical distribution of the genus Discorhabdella.

Metachromins X and Y from a marine sponge Spongia sp. and their effects on cell cycle progression.

New sesquiterpene quinones, metachromins X (1) and Y (2), together with the known metachromins C (3), J (4), and T (5), were isolated as inhibitors of cell cycle progression in the HeLa/Fucci2 cells. The structure of 1 was assigned by spectroscopic data and confirmed by a total synthesis. The planar structure of 2 was determined by interpretation of spectroscopic data, whereas its absolute configuration was analyzed by a combination of chiral HPLC and CD spectroscopy. Metachromins X (1) and C (3) arrested the cell cycle progression of HeLa/Fucci2 cells at S/G2/M phase.

First record of Hamacantha (Porifera, Demospongiae, Merliida, Hamacanthidae) from Japan, with description of two new species.

Two new species of thinly encrusting sponge Hamacantha (Demospongiae, Merliida, Hamacanthidae) are described from Japan. Hamacantha (Vomerula) mamoi sp. nov. was collected from Sagami Bay, and Hamacantha (Vomerula) umisachii sp. nov. from off Hachijo Island. This is the first record of Hamacantha and the Hamacanthidae from Japan. H. (V.) mamoi sp. nov. is characterized by having styles, two types of diancistras and one of sigmas. Only two known species have the same spicule composition: H. (V.) acerata Lévi, 1993 and H. (V.) esperioides Ridley Dendy, 1886, described from New Caledonia, and south-west Africa and south-east South America, respectively. H. (V.) acerata has larger diancistras and much smaller sigmas compared with those of H. (V.) mamoi sp. nov. H. (V.) esperioides can be separated by having larger styles and smaller sigmas than those of H. (V.) mamoi sp. nov. H. (V.) umisachii sp. nov is characterized by having styles, diancistras, cyrtancistra-like diancistras and sigmas. Hamacantha (V.) carteri Topsent, 1904 seems to have similar spicule composition, however the size of all spicule types is different.

Isolation and identification of N6-isopentenyladenosine as the cytotoxic constituent of a marine sponge Oceanapia sp.

N6-Isopentenyladenosine (i6A) was isolated from a marine sponge Oceanapia sp. as the major cytotoxic constituent along with N6-isopentenyladenosine 5'-monophosphate (i6AP) which was inactive. The structures of i6A and i6AP were assigned by a combination of the analysis of NMR spectroscopy and mass spectrometry. This is the first isolation of i6A and i6AP from a marine sponge.

Scrobiculosides A and B from the deep-sea sponge Pachastrella scrobiculosa.

Two new steroidal saponins, scrobiculosides A and B, were isolated from the deep-sea sponge Pachastrella scrobiculosa, collected at a depth of 200 m off Miura Peninsula, Japan. The aglycones of scrobiculosides A and B feature a vinylic cyclopropane and a ∆24,25 exomethylene on the side chains, respectively. Both saponins have a common sugar moiety composed of ß-D-galactopyranosyl-(1 → 2)-6-acetyl-ß-D-glucopyranoside, with the exception of an acetyl group on C6″ in scrobiculoside A. Scrobiculoside A exhibited cytotoxicity against HL-60 and P388 cells, with IC50 values of 52 and 61 µM, respectively.

A novel sponge-derived protein thrombocorticin is a new agonist for thrombopoietin receptor.

We screened 868 marine extracts in search of hematopoietic molecules resulted in findings of several extracts that proliferated Ba/F3-HuMpl cells but not the cells expressed with other hematopoietic cytokine receptors, EPO and G-CSF. Separation of the most potent extract of a Micronesian sponge Corticium sp., guided by the cell proliferation assay using Ba/F3-HuMpl cells resulted in an isolation of thrombocorticin (ThC), a novel 14 kDa protein as an active principal. ThC displayed concentration-dependent proliferation of Ba/F3-HuMpl cells, and had a stronger activity than that of eltrombopag, a small molecule drug used to treat thrombocytopenia. ThC induced phosphorylation of STAT5, suggesting that it activates Jak/STAT pathway as in the case of TPO. These results together indicated that ThC is a specific agonist for c-Mpl, although the size and shape differs largely from TPO. Here we present isolation, characterization and biological activity of ThC.