Sponge Stylissa Research Articles

Discovery of Anti-Inflammatory Alkaloids from Sponge Stylissa massa Suggests New Biosynthetic Pathways for Pyrrole-Imidazole Alkaloids.

Pyrrole-imidazole alkaloids (PIAs) are a class of marine sponge derived natural products which have complex carbon frameworks and broad bioactivities. In this study, four new alkaloids, stylimassalins A-B (1-2), 3, and 5, together with two known compounds (4 and 6), were isolated from Stylissa massa. Compounds 2, 4, and 6 are the C-2 brominated analogues of 1, 3, and 5, respectively. Their structures display three different scaffolds, of which scaffold 1 (compounds 1,2) is new. A new biosynthetic pathway from oroidin, through spongiacidin, to latonduine and scaffold 1 was proposed by our group, in which the C12-N13-cleavaged compounds of spongiacidin (scaffold 2), dubbed seco-spongiacidins (3 and 4), are recognized as a key bridged scaffold, to afford PIA analogues (1,2 and 5,6). An anti-inflammatory evaluation in a zebrafish inflammation model induced by copper sulphate (CuSO4) demonstrated that stylimassalins A and B (1 and 2) could serve as a promising lead scaffold for treating inflammation.

Exploring Indonesian Sponge-Associated Marine Aspergillus hortai: Characterization of Bioactive Compounds with Potential Anti-Escherichia coli Properties

Sponge-associated marine fungi are potential source for secondary metabolite compounds. The aim of this research was to investigate sponge-associated marine fungus as secondary metabolite producers against Escherichia coli. The fungus was isolated from Indonesian marine sponge Stylissa sp. and identified as Aspergillus hortai through a combination of morphological and molecular characteristics of ITS DNA and β-tubulin genes. The fungus was tested against E. coli using fungal broth and mycelial extracts. The optimized condition was achieved by fungal broth grown in corn meal broth at 6-days of shaking incubation. Fungal extract was produced using three liters of filtered fungal broth and extracted in ethyl acetate. The antibiotic activity of the extract is vulnerable to 45°C heat and basic or acidic conditions. Therefore, the extraction was done at pH 7 with evaporation at 40°C. The extract shows 7 major bands on TLC with 1 band shows activity against E. coli (Rf 0.81) on bioautogram. The band was observed as a yellow color and turned black in short-wave UV and did not show any fluorescence in long-wave UV. This research shows that sponge-associated marine fungi obtained from Indonesia has the potential as anti E. coli worth to be explored for searching new antibiotics.

Cytotoxic and Anti-proliferative Effects of Ethanol Extract of Marine Sponge Stylissa carteri on Colon Cancer HCT-116 Cell Line

Colorectal cancer is one of the most diagnosed cancers in the world. KRAS mutations in colon cancer are being responsible for the progressiveness and resistance of the standard therapeutic available. Marine sponge is one the sources for chemotherapy. Stylissa carteri is a marine sponge that lives in Indonesia and its anti-cancer effects are starting to be explored nowadays. The purpose of this study was to determine the cytotoxicity and anti-proliferative effect of ethanol extract of Stylissa carteri against colon cancer cells with KRAS mutations HCT-116 cells. This was an in vitro study using colon cancer cell line HCT-116 which was tested by 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and trypan blue assay. The trypan blue assay was performed on control and treated cells at 72 h. The MTT assay was performed on cells which were previously incubated with Stylissa carteri extract. Sponge Stylissa carteri was taken from Pramuka island, Taman Nasional Kepulauan Seribu, Jakarta. The IC50 of ethanol extract of Stylissa carteri is 5 μg/mL (R square 0.9550) in HCT-116 cells. The trypan blue assay showed doubling time of incubated cell for 48 h was 26.10 h for control and 39.69 h for treated cells, respectively. Ethanol extract of Stylissa carteri has cytotoxic and anti-proliferative effects in HCT-116 colon cancer cells with KRAS mutation.Keywords: Colon Cancer, HCT-116, KRAS Mutation, Marine Sponge, Stylissa carteri.

Total synthesis of (±)-N-methyldibromoisophakellin and N-methylugibohlin via net [3 + 2] cycloguanidinylations employing 2-amido-1,3-diamino-allyl cations

A concise total synthesis of (±)-N-methyldibromoisophakellin, a member of the monomeric pyrrole–aminoimidazole alkaloid family isolated from the marine sponge Stylissa carbica, was achieved via a net [3 + 2] cycloaddition to install the cyclic guanidine. This ring annulation employs a 2-amido-1,3‑aminoallyl cation obtained under oxidative conditions from variously N-substituted guanidines which in one instance led to isolation of a tetracycle bearing a carbinolamine center through subsequent benzylic oxidation. Finally, the serendipitous formation of a unique, related alkenyl guanidine, N-methylugibohlin, achieved via ring opening of cyclic guanidine under acidic conditions suggests that ugibohlin may be an artifact of isolation.

A Series of New Pyrrole Alkaloids with ALR2 Inhibitory Activities from the Sponge Stylissa massa.

Twelve new and four known alkaloids including five different structural scaffolds were isolated from the sponge Stylissa massa collected in the South China Sea. Compound 1 is the first identified precursor metabolite of the classic 5/7/5 tricyclic skeleton with unesterified guanidine and carboxyl groups, compounds 2–5 and 13–15 belong to the spongiacidin-type pyrrole imidazole alkaloids (PIAs). Z- and E-configurations of the spongiacidin-type PIAs often appeared concomitantly and were distinguished by the chemical shift analysis of 13C NMR spectra. The structures of all twelve new compounds were determined by NMR, MS, and ECD analysis combined with single-crystal data of compounds 1, 5, and 10. In the aldose reductase (ALR2) inhibitory assay, six 5/7/5 tricyclic compounds (2–5, 13–15) displayed significant activities. Compounds 13 and 14, as the representative members of spongiacidin-PIAs, demonstrated their ALR2-targeted activities in SPR experiments with KD values of 12.5 and 6.9 µM, respectively.

The Ethyl Acetate Fraction of Marine Sponge Stylissa carteri Induces Breast Cancer Cell Death via Upregulation of Mcl-1S: an In vitro Study.

Objective:To evaluate the potency of the fraction of marine sponge Stylissa carteri in inducing cell death, inhibiting spheroid growth, and its impact on pro-apoptotic protein Mcl-1S in breast cancer cells. Methods: Stylissa carteri were collected from Pramuka Island followed by ethanol extraction and ethyl acetate fractionation. To evaluate the cytotoxic effect of fraction, the HCC-1954, MDA MB 231, and MCF-7 cells were treated with the fraction of Stylissa carteri and MTT assay was then performed. The effect on spheroid growth was evaluated in HCC-1954 cells. The combined effect of the ethyl acetate fraction and paclitaxel were analyzed using combination index (CI) and immunoblotting on the pro-apoptotic protein Mcl-1S. Furthermore, compounds in this fraction were identified using GC-MS. Results:Data showed that both the MDA MB 231 and HCC-1954 cells were interestingly more sensitive to the fraction as compared with MCF-7 cells. The IC50 of the ethyl acetate fraction on HCC-1954, MDA MB 231 and MCF-7 were 4.1 µg/ml, 3.9 µg/ml, and 123.8 µg/ml, respectively. In addition, the fraction triggered spheroid destruction within 10 days. The CI of paclitaxel and ethyl acetate fraction of Stylissa carteri were less than 0.52. Moreover, this combination induced upregulation of the Mcl-1S protein. Furthermore, some fatty acid-based structures were predicted as the major compounds in this fraction. Conclusion:The ethyl acetate fraction of Stylissa carteri induces cell death and spheroid destruction in aggressive breast cancer cells. It has a synergistic cytotoxic effect with paclitaxel on MDA MB 231 cell death and upregulates Mcl-1S protein.

In Vitro Pancreatic Lipase Inhibition by Marine Fungi Purpureocillium lilacinum Associated with Stylissa sp. Sponge as Anti-obesity Agent

This study aimed to evaluate the potential of marine fungus Purpureocillium lilacinum isolated from an Indonesian marine sponge Stylissa sp. as an anti-obesity agent through pancreatic lipase inhibition assay. The fungus was identified as P. lilacinum through morphological and molecular characteristics. The fungal extract’s inhibition activity and kinetics were evaluated using spectrophotometry and Lineweaver-Burk plots. Ethyl acetate and butanol were used for extraction. Both extracts showed pancreatic lipase inhibition in a concentration-dependent manner. Both crude extracts were then fractionated once. All fractionated extracts showed inhibitory activity above 50%, with the highest activity found in fraction 5 of ethyl acetate at 93.41% inhibition. The best fractionated extract had an IC50value of 220.60 µg.mL-1. The most active fraction of P. lilacinum had a competitive-type inhibitor behavior as shown by the value of Vmax not significantly changing from 388.80 to 382.62 mM pNP.min-1, and the Michaelis-Menten constant (KM) increased from 2.02 to 5.47 mM in the presence of 500 µg.mL-1 fractionated extract. Metabolite identification with LC-MS/MS QTOF suggested that galangin, kaempferol, and quercetin were responsible for the observed lipase inhibition.

Total Phenolic Content (TPC), Total Flavonoid Content (TFC) and Antioxidants Activity of Marine Sponge Stylissa flabelliformis Ethanol Extract

Marine sponge Stylissa flabelliformis is a marine sponge species that is widely found in Indonesia. Marine sponges have been proven to have pharmacological activities including wound healing, cytotoxicity and antimicrobial activity. All these activities are related to its antioxidant potential. Antioxidants are important for human health due to its ability to protect cell damage caused by free radicals. The aim of this research was to study the antioxidant activity of marine sponge (Stylissa flabelliformis) and to observe the phytochemical compound of the marine sponge such as the phenolic and flavonoid content. Extraction was performed using cold maceration with 96% ethanol solvent and continued by rotary evaporator to get the concentrated extract. Antioxidants activity was analysed using DPPH (2,2-diphenyl-1-picrylhydrazyl) method, which examines the inhibitory concentration (IC50) of the ethanol extract. Total phenolic content (TPC) was examined using Gallic acid as the standard, while total flavonoid content (TFC) was examined using quercetin as the standard. The result showed a concentration-dependent antiradical activity by reduction of DPPH with an IC50 value 2000 µg/mL. Total phenolic content was 152,67 mg GAE/g, while the total flavonoid content was 155,79 mg QE/g.

Cytotoxic and Antimicrobial Activities of Ethyl Acetate Extract from Fungus Trichoderma reesei strain JCM 2267, Aspergillus flavus strain MC- 10-L, Penicillium sp, and Aspergillus fumigatus Associated with Marine Sponge Stylissa flabelliformis

This study was to investigate the cytotoxic and antimicrobial activities of ethyl acetate extract yielded from fermented fungi Trichoderma reesei strain: JCM 2267, Aspergillus flavus strain MC-10-L, Penicillium sp, and Aspergillus fumigatus associated with Stylissa flabelliformis sponge, and also to investigate the significant component in ethyl acetate extract of it. Antimicrobial experimentation was performed to various microbes with liquid microdilution method. The assessment of antimicrobials was undertaken by observing the value of MIC50. Cytotoxic testing was performed using MTT assay method. The cytotoxic activity evaluation was conducted by finding the value of IC50. The compound analysis in the ethyl acetate extract was used GC-MS. The result showed that in the antimicrobial experimentation, there was a variation in the percentage of inhibition where the smallest MIC50 values were found in Aspergillus fumigatus fungi ethyl acetate extract against Candida albicans ATCC 10231 at 1.3g/mL. The result of the cytotoxic test against tumor cell line T47D, the lowest IC50 was found in Penicillium sp fungi with 111g/mL value. Aspergillus flavus strain MC-10-L fungi, Penicillium sp, and Aspergillus fumigatus obtained from sponge isolation Stylissa flabelliformis have antimicrobial and cytotoxic activity with various range. All fungi extracts are not toxic against normal cells (Vero cells). The class of compounds in ethyl acetate fungi extract Trichoderma reesei strain JCM 2267 are mostly cyclohexane.

GPCR Pharmacological Profiling of Aaptamine from the Philippine Sponge Stylissa sp. Extends Its Therapeutic Potential for Noncommunicable Diseases.

We report the first isolation of the alkaloid aaptamine from the Philippine marine sponge Stylissa sp. Aaptamine possessed weak antiproliferative activity against HCT116 colon cancer cells and inhibited the proteasome in vitro at 50 µM. These activities may be functionally linked. Due to its known, more potent activity on certain G-protein coupled receptors (GPCRs), including -adrenergic and -opioid receptors, the compound was profiled more broadly at sub-growth inhibitory concentrations against a panel of 168 GPCRs to potentially reveal additional targets and therapeutic opportunities. GPCRs represent the largest class of drug targets. The primary screen at 20 µM using the -arrestin functional assay identified the antagonist, agonist, and potentiators of agonist activity of aaptamine. Dose-response analysis validated the -adrenoreceptor antagonist activity of aaptamine (ADRA2C, IC50 11.9 µM) and revealed the even more potent antagonism of the -adrenoreceptor (ADRB2, IC50 0.20 µM) and dopamine receptor D4 (DRD4, IC50 6.9 µM). Additionally, aaptamine showed agonist activity on selected chemokine receptors, by itself (CXCR7, EC50 6.2 µM; CCR1, EC50 11.8 µM) or as a potentiator of agonist activity (CXCR3, EC50 31.8 µM; CCR3, EC50 16.2 µM). These GPCRs play a critical role in the treatment of cardiovascular disease, diabetes, cancer, and neurological disorders. The results of this study may thus provide novel preventive and therapeutic strategies for noncommunicable diseases (NCDs).

Antimicrobial activity of natural compounds from sponge – derived fungus Aspergillus flocculosus 01NT.1.1.5

The Aspergillus fungi have been an important source of natural products that are useful for exploration in medicine, agriculture and industry. In our continuous investigation to search for new antimicrobial agents from marine-derived fungi, one new phomaligol A2 (1), together with three known compounds, wasabidienone E (2), aspertetranone D (3) and mactanamide (4), were obtained from the EtOAc extract of the culture medium of the marine-derived fungus Aspergillus flocculosus (A. flocculosus) 01NT.1.1.5 isolated from the sponge Stylissa sp. at Nhatrang Bay, Vietnam. Their chemical structures were elucidated by analysis of 1D and 2D NMR and mass spectroscopic data, as well as by comparison of the corresponding data to those previously reported in the literature. Furthermore, the aim of this study was also to evaluate the antimicrobial activity of these compounds against pathogenic microbes including Escherichia coli (E. coli) ATCC 25922, Pseudomonas aeruginosa (P. aeruginosa) ATCC 27853, Staphylococcus aureus (S. aureus) ATCC 25923, Bacillus cereus (B. cereus) ATCC 11778, Streptococcus faecalis (S. faecalis) ATCC 19433, Listeria monocytogenes (L. monocytogenes) ATCC 19111, and Candida albicans (C. albicans) ATCC 10231. Among the compounds, 1-3 were inhibitory on the growth of the yeast C. albicans with minimum inhibitory concentration (MIC) value of 16 μg/mL, which was more potent than amoxicillin and cefotaxime (MIC > 256 μg/mL), antimicrobial drugs as positive references. Moreover, compounds 1-4 were also found to be active against other pathogens including P. aeruginosa and S. faecalis with MIC values of 16 μg/mL and 32 μg/mL, respectively. Compound 4 had no inhibitory activity against L. monocytogenes, whereas compounds 1-3 had ability to against this strain with MICs of 32 to 64 μg/mL. Four of tested compounds exhibited antibacterial activity against B. cereus and E. coli with MIC values of 64-128 μg/mL. This is the first report about these compounds with antimicrobial activity obtained from marine fungus A. flocculosus isolated in Vietnam.

Futunamine, a Pyrrole-Imidazole Alkaloid from the Sponge Stylissa aff. carteri Collected off the Futuna Islands.

The chemical investigation of the sponge Stylissa aff. carteri collected around Futuna Islands in the Pacific Ocean led to the isolation of three new dimeric pyrrole 2-aminoimidazole alkaloids (PIAs). Futunamine (1) features an unprecedented pyrrolo[1,2-c]imidazole core, while two other new dimeric PIAs were identified as analogues of palau'amine. Together with other known PIAs isolated from this species, they were shown to exhibit anti-inflammatory and neuroprotective activities.

The ethyl acetate fraction of sponge Stylissa carteri decreases viability in HER2+ trastuzumab-resistant breast cancer cells

Background: HER2+ breast cancer is a very aggressive type of breast cancer. Although trastuzumab, specifically targeted for HER2, has been used for breast cancer treatments, some patients become resistant to trastuzumab. A marine sponge is one of the potential sources of anticancer agents. One of marine sponges commonly found in Indonesia is Stylissa carteri, but it has not been explored extensively. Objective: This study aimed to identify cytotoxic effects of the ethyl acetate fraction of Stylissa carteri on HCC-1954, HER2+ trastuzumab-resistant breast cancer cells, by assessing cell viability and determining IC50 value. Methods: This study was an experimental in vitro study conducted in The Cell Culture Laboratory, Faculty of Medicine Universitas Padjadjaran on February 2018 to June 2018. The Stylissa carteri was collected from Pramuka Island, Kepulauan Seribu National Park Jakarta. HCC-1954 cells were treated by serial concentration of fractions and were incubated for 72 hours. Cell viability were observed under a microscope and analysed with MTT assay. The IC50 value was also determined by using four parametric logistic regression (4PL) method by Sigmaplot version 12.0. Result: Data of this study showed descent of cell viability significantly when exposing the ethyl acetate fraction of Stylissa carteri. There was a decrease of 49% cell viability in 10 µg/ml of the ethyl acetate fraction of Stylissa carteri. The estimated IC50 value was 9.25 µg/ml. Conclusion: This result indicated that the ethyl acetate fraction of Stylissa carteri has cytotoxic effects on HER2+ trastuzumab-resistant breast cancer cells.

(10Z)-Debromohymenialdisine from Marine Sponge Stylissa sp. Regulates Intestinal Inflammatory Responses in Co-Culture Model of Epithelial Caco-2 Cells and THP-1 Macrophage Cells.

Crohn’s disease (CD) and ulcerative colitis (UC), collectively referred to as inflammatory bowel disease (IBD), are autoimmune diseases characterized by chronic inflammation within the gastrointestinal tract. Debromohymenialdisine is an active pyrrole alkaloid that is well known to serve as a stable and effective inhibitor of Chk2. In the present study, we attempted to investigate the anti-inflammatory properties of (10Z)-debromohymenialdisine (1) isolated from marine sponge Stylissa species using an intestinal in vitro model with a transwell co-culture system. The treatment with 1 attenuated the production and gene expression of lipopolysaccharide (LPS)-induced Interleukin (IL)-6, IL-1β, prostaglandin E2 (PGE2), and tumor necrosis factor-α in co-cultured THP-1 macrophages at a concentration range of 1–5 μM. The protein expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 were down-regulated in response to the inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) translocation into the nucleus in cells. In addition, we observed that 1 markedly promoted the nuclear translocation of nuclear factor erythroid 2 related factor 2 (Nrf2) and subsequent increase of heme oxygenase-1 (HO-1) expression. These findings suggest the potential use of 1 as a pharmaceutical lead in the treatment of inflammation-related diseases including IBD.

Changes in the metabolic potential of the sponge microbiome under ocean acidification

Anthropogenic CO2 emissions are causing ocean acidification, which can affect the physiology of marine organisms. Here we assess the possible effects of ocean acidification on the metabolic potential of sponge symbionts, inferred by metagenomic analyses of the microbiomes of two sponge species sampled at a shallow volcanic CO2 seep and a nearby control reef. When comparing microbial functions between the seep and control sites, the microbiome of the sponge Stylissa flabelliformis (which is more abundant at the control site) exhibits at the seep reduced potential for uptake of exogenous carbohydrates and amino acids, and for degradation of host-derived creatine, creatinine and taurine. The microbiome of Coelocarteria singaporensis (which is more abundant at the seep) exhibits reduced potential for carbohydrate import at the seep, but greater capacity for archaeal carbon fixation via the 3-hydroxypropionate/4-hydroxybutyrate pathway, as well as archaeal and bacterial urea production and ammonia assimilation from arginine and creatine catabolism. Together these metabolic features might contribute to enhanced tolerance of the sponge symbionts, and possibly their host, to ocean acidification.

Bioactive Compounds in the Ethanol Extract of Marine Sponge Stylissa carteri Demonstrates Potential Anti-Cancer Activity in Breast Cancer Cells

Objective:Despite advanced treatment options available, drug resistance develops in breast cancer (BC) patients requiring novel effective drugs. Stylissa carteri, a marine sponge predominantly living in Indonesia territories, has not been extensively studied as anti-cancer. Therefore, this study targeted to assess the anti-tumor activity of the ethanol extract of S. carteri in BC cells. Methods: S. carteri was collected from Pramuka Island, at Kepulauan Seribu National Park, Jakarta, Indonesia and extracted using ethanol. Different BC cells including MDA MB 231, MDA MB 468, SKBR3, HCC-1954 and MCF-7 cells were treated with this extract for cytotoxic analysis using MTT assay. Spheroid growth assay and apoptosis assay were conducted in HCC-1954 cells. In addition, cell migration analysis and synergistic activity with doxorubicin or paclitaxel were conducted in MDA MB 231 cells. This extract was subjected also for GC-MS analysis. Results:The results show that ethanol extract of S. carteri demonstrated a cytotoxic activity in BC cells. The IC50 of this extract was lower 15 μg/ml in MDA MB 231, MDA MB 468, SKBR3, and HCC-1954 cells. Moreover, this extract inhibited spheroids growth and induced apoptosis in HCC-1954 cells. It inhibited cell migration and demonstrated a synergistic activity with doxorubicin or paclitaxel on triggering cell death in MDA MB 231 cells. Furthermore, GC-MS analysis indicated that this extract contained 1,2-Benzenediol, Dibutyl phthalate and 9,12-Octadecadienoic acid, ethyl ester. Conclusion:Our preliminary data indicate a potential anti-tumor activity of ethanol extract of S. carteri in breast cancer cells.

EFFECT OF CULTURE CONDITIONS FOR ANTIMICROBIAL ACTIVITY OF MARINE - DERIVED FUNGUS ASPERGILLUS FLOCCULOSUS 01NT.1.1.5

The biosynthesis of compounds with antibiotic activity produced by marine fungi, strongly depends on their growth conditions. A good understanding of the role of culture conditions in the biosynthesis of metabolites may lead to better exploitation of microbial metabolites. In this study, the influence of culture conditions including incubation period, initial pH and salinity on antimicrobial activity and secondary metabolites production of marine fungus 01NT.1.1.5 was investigated. This isolate, obtained from sponge Stylissa sp. in Nha Trang Bay, exhibited a broad spectrum of in vitro antimicrobial activity to Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Listeria monocytogenes ATCC 19111, Streptococcus faecalis ATCC 19433 and Candida albicans ATCC 10231. According to morphological characteristics and sequence analysis of 28S rDNA, the fungus was identified as Aspergillus flocculosus. The results indicated that antimicrobial activity and metabolite amount were highest when the fungus was cultivated in rice medium with incubation period of 20 days. The optimum salinity of 35 g/L and initial pH of 6.0 were found for the maximum antibiotic production. The colony growth, antimicrobial activity and production of secondary metabolites of the strain A. flocculosus 01NT.1.1.5 varied depending on salt concentrations and initial pH of medium. Particularly, extract of this fungus only showed activity against C. albicans when it was cultured in medium with 30-35 g/L salinity and initial pH 4.0-8.0. The results indicate that salinity and initial pH along with cultivation period are important factors influencing antimicrobial activity and secondary metabolites of A. flocculosus 01NT.1.1.5, and might be for other marine fungi.

Inhibitors of RANKL-induced osteoclast differentiation from the Marine Fungus Aspergillus flocculosus isolated from a Sponge Stylissa sp.

Inhibitors of RANKL-induced osteoclast differentiation from the Marine Fungus Aspergillus flocculosus isolated from a Sponge Stylissa sp.

Compositional analysis of archaeal communities in high and low microbial abundance sponges in the Misool coral reef system, Indonesia

ABSTRACTThe high/low microbial abundance (HMA/LMA) dichotomy in sponges has been the subject of several studies over recent years, but few studies have analysed this dichotomy in terms of the sponge archaeal community and function. Using a 16S rRNA gene barcoded pyrosequencing approach and predictive functional analysis (PICRUSt) we compared the archaeal composition, richness and predicted function of one HMA sponge (Xestospongia testudinaria), one LMA sponge (Stylissa carteri) and one sponge species of unknown microbial abundance (Aaptos lobata). Although most of the archaeal sequences were assigned to the Crenarchaeota phylum, S. carteri had the highest percentage of sequences assigned to the Euryarchaeota phylum. Variation among sponge species explained >85% of the variation in archaeal operational taxonomic unit (OTU) composition with each sponge species forming a distinct cluster. There were significant differences in predicted PICRUSt profiles among sponge species, suggesting that archaeal communities present in the studied sponge species may perform different functions. X. testudinaria and A. lobata were similar both in terms of OTU and KEGG orthologues composition, which may indicate that A. lobata is a HMA sponge. Additionally, some of the most enriched functions seem to be related to traits associated with high and low microbial abundance sponges.

Suppression of RANKL-Induced Osteoclastogenesis by the Metabolites from the Marine Fungus Aspergillus flocculosus Isolated from a Sponge Stylissa sp.

A new α-pyrone merosesquiterpenoid possessing an angular tetracyclic carbon skeleton, ochraceopone F (1), and four known secondary metabolites, aspertetranone D (2), cycloechinulin (3), wasabidienone E (4), and mactanamide (5), were isolated from the marine fungus Aspergillus flocculosus derived from a sponge Stylissa sp. collected in Vietnam. The structures of Compounds 1–5 were elucidated by analysis of 1D and 2D NMR spectra and MS data. All the isolated compounds were evaluated for anti-proliferation activity and their suppression effects on receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation using tartate-resisant acid phosphatase (TRAP). Compounds 1–5 had no anti-proliferative effect on human cancer cell lines up to 30 μg/mL. Among these compounds, aspertetranone D (2) and wasabidienone E (4) exhibited weak osteoclast differentiation inhibitory activity at 10 μg/mL. However, mactanamide (5) showed a potent suppression effect of osteoclast differentiation without any evidence of cytotoxicity.