Search Results (958)

Marine sponges are known to be associated with diverse and functionally specialized microbial consortia that are implicated in host metabolism, biogeochemical cycling, and bioactive compounds production. The microbiome diversity and composition of nine sponge species from the remote waters of Gageodo Island, Korea, were evaluated via full-length 16S rRNA sequencing and bioinformatic analyses. Each sponge species harbored a distinct microbial community, with differences potentially influenced by ecological factors, evolutionary history, and host–symbiont associations. The dominant microbial phyla identified across the sponge samples include Pseudomonadota, Cyanobacteriota, Acidobacteriota, Planctomycetota, and Chloroflexota, which were widely distributed across samples. In addition, the classes Gammaproteobacteria, Acidobacteriae, and Anaerolineae appeared as characteristic groups, being particularly abundant in specific sponge samples. Community structures ranged from dominance by one or two abundant taxa to more taxonomically diverse and evenly distributed microbiomes. A notable proportion of sequences were unassignable to known taxa, suggesting the occurrence of previously uncharacterized microbial lineages in these sponges. By combining host species identification with microbiome profiling, this study provides new foundations on the microbial ecology of Korean sponge holobionts, providing higher-resolution taxonomic classification, improved diversity estimates, and enhanced characterization of evolutionary relationships among symbionts. These findings may support future investigations into host–microbe interactions, potential ecological functions, and the management of marine genetic resources. Full article

Botryomeroterpenoids A (1) and B (2), two new andrastin-type meroterpenoids, along with two known analogues (3 and 4), were isolated from sponge-derived fungus Botryosporium sp. S5I2-1. Their structures were characterized by detailed spectroscopic analysis. Meanwhile, the absolute configurations of 1 and 2 were elucidated by comparing experimental and calculated ECD spectra. Compounds 1 and 2 were the first examples of andrastin-type meroterpenoids isolated from this genus, especially Compound 1 which represented the initial instance of 18-norandrastin-type meroterpenoids. Furthermore, the antibacterial activities of all compounds were also evaluated. However, the results indicated that these compounds showed no significant inhibitory activity against the tested bacteria with minimum inhibitory concentration (MIC) values of 32–64 μg/mL. Full article

We recently reported that onnamide A, a marine-derived natural compound isolated from the sponge Theonella sp., inhibits the entry process of SARS-CoV-2 infection. However, its antiviral activity against other viruses remains largely unexplored. Here, we investigated the effects of onnamide A and its structurally related analog, onnamide B, on hepatitis B virus (HBV) infection. Using iNTCP cells, a hepatoblastoma-derived cell line permissive to HBV infection, we found that onnamides A and B exhibited cytotoxicity, with CC₅₀ values of 0.53 ± 0.10 μM and 2.37 ± 0.25 μM, respectively. Following HBV infection, the levels of total HBV RNA were significantly reduced by onnamide A (IC₅₀ = 0.06 ± 0.01 μM) and onnamide B (IC₅₀ = 0.23 ± 0.06 μM). Notably, both compounds markedly decreased the levels of HBV pregenomic RNA. Furthermore, significant inhibition was particularly evident when onnamide treatment was initiated after HBV infection. Consistent with these observations, onnamides did not affect HBV binding, entry, or covalently closed circular DNA formation, but they significantly suppressed HBV RNA transcription. In particular, the transcriptional activities driven by the core and X promoters were markedly inhibited by onnamide treatment. Taken together, our findings demonstrate that onnamides possess potent anti-HBV activity and highlight their potential as candidate compounds targeting HBV RNA transcription. Full article

Marine sponges possess complex metabolic systems that support their growth, physiology, and ecological interactions. However, the primary metabolic capacity of the sponge hosts remains incompletely characterized at the molecular level. In this study, we performed de novo transcriptome sequencing of a pooled sample of three individuals of Xestospongia sp. collected in Vietnam, using a high-throughput Illumina sequencing system, to characterize the host-derived metabolic pathways. A total of 43,278 unigenes were assembled, of which 69.15% were functionally annotated using multiple public databases. Functional annotation revealed a broad repertoire of genes associated with core metabolic pathways, including carbohydrate, lipid, and sterol metabolisms, as well as cofactor-related processes. Specifically, complete pathways involved in folate biosynthesis, terpenoid backbone biosynthesis, ubiquinone (Coenzyme Q) metabolism, and steroid biosynthesis were identified, reflecting the independent metabolic framework of the sponge host. Several highly expressed genes related to these pathways, including COQ7, ERG6, NUDX1, QDPR, and PCBD, were detected, and their expression patterns were confirmed by quantitative RT-PCR. Furthermore, protein-based phylogenetic analyses indicated that these genes are closely related to homologous proteins from other sponge species, supporting their host origin. This study provides the first comprehensive transcriptomic resource for Xestospongia sp. from Vietnam, and offers baseline molecular insights into the primary metabolic capacity of the sponge host. These data establish a foundation for future investigations of sponge physiology and host–microbe metabolic partitioning. Full article

Anthonoic acids A–C (1–3), the first representatives of sulfated and N-(2-hydroxyethyl)-substituted lipidic α-amino acids, were isolated along with their plausible precursor, anthamino acid A (4), from the marine sponge Antho ridgwayi. The structures of these compounds were determined using the analysis of 1D and 2D NMR and HR ESI mass spectra. A structural feature of 1–4, compared to all previously known lipidic amino acids, is the presence of a sulfate group near the end opposite the amino acid terminus. At a concentration of 1 µM, anthonoic acids A–C (1–3) effectively protected H9c2 and SH-SY5Y cells in biotests, which modeled hypoxia induced by the addition of CoCl₂ to the medium and damage caused by ischemia/reperfusion. These natural products act via the Nrf2-mediated pathway by reducing intracellular ROS levels, accompanied by the upregulation of SOD activity, which is controlled by the Nrf2 transcriptional factor. Anthonoic acids A–C (1–3) do not activate the transcriptional activity of NF-κB but inhibit ATP-induced cell damage and calcium influx, indicating the involvement of P2X7 receptors in the cytoprotective effect of anthonoic acids A–C. Full article

Marine sponges are recognized as reservoirs of diverse microorganisms that produce bioactive natural compounds. In this study, we conducted a metataxonomic analysis of Geodia cydonium specimens collected from four sites in Italy: Secca delle Fumose (Gulf of Naples, Tyrrhenian Sea), Mar Piccolo of Taranto and an Integrated Multi-Trophic Aquaculture (IMTA) system in Mar Grande of Taranto (both located in the Ionian Sea), and Polignano a Mare (Adriatic Sea). Our results revealed a highly diverse microbial community within the sponges, encompassing 24 bacterial phyla. Among these, Chloroflexota was the most abundant phylum, accounting for an average of 30.2% of the total community across all samples. In addition, the majority of the microbiota was composed of Actinomycetota, Proteobacteria, Acidobacteriota, Poribacteriota, Gemmatimonadota, and Dadabacteria. The sponge sample from Polignano a Mare exhibited the richest and most diverse bacterial community. This observation was supported by phylogenetic analysis, which identified seven bacterial genera, Albidovulum, Filomicrobium, Microtrix, Gaiellales, D90 (Gammaproteobacteria class), and Blastopirellula, exclusive to this site. Several of these taxa are known for their potential biotechnological applications, underlining the significance of site-specific microbial diversity in G. cydonium. Full article

Frequent crude oil spills during offshore oil and gas production and transportation have inflicted irreversible detrimental effects on both human activities and marine ecosystems; with particular risks of secondary disasters such as combustion and explosions. To address these challenges; advanced oil sorption technologies have been developed to overcome the inherent limitations of conventional remediation methods. In this study, a flame-retardant protective coating was fabricated on melamine sponge (MS) through precipitation polymerization of octa-aminopropyl polyhedral oligomeric silsesquioxane (POSS) and hexachlorocyclotriphosphazene (HCCP), endowing the MS@PPOS-PDMS-Si composite with exceptional char-forming capability. Secondary functional layer: By coupling the complementary physicochemical properties of polydimethylsiloxane (PDMS) and SiO₂ nanofibers, we enabled them to function jointly, achieving superior performance in the material systems; this conferred enhanced hydrophobicity and structural stability to the MS matrix. Characterization results demonstrated a progressive reduction in peak heat release rate (PHRR) from 137.66 kW/m² to118.35 kW/m², 91.92 kW/m², and ultimately 46.23 kW/m², accompanied by a decrease in total smoke production (TSP) from 1.62 m² to 0.76 m², indicating significant smoke suppression. Furthermore, the water contact angle (WCA) exhibited substantial improvement from 0° (superhydrophilic) to 140.7° (highly hydrophobic). Cyclic sorption–desorption testing revealed maintained oil–water separation efficiency exceeding 95% after 10 operational cycles. These findings position the MS@PPOS-PDMS-Si composite as a promising candidate for emergency oil spill response and marine pollution remediation applications, demonstrating superior performance in fire safety, environmental durability, and operational reusability. Full article

Four new methionine sulfoxide-containing diketopiperazines, (+)-dysidmetsulfoxide A [(+)-1], (+)-dysidmetsulfoxide B [(+)-2], (+)-dysidmetsulfoxide C [(+)-3] and (−)-dysidmetsulfoxide C [(−)-3], were isolated from the South China Sea sponge Dysidea sp. These compounds represented the first example of diketopiperazines possessing the unit of methionine sulfoxide (MetO) isolated from marine sponges. As it was difficult to determine the configuration of chiral sulfur atom in the thionyl group, the structures with absolute configurations of these compounds were elucidated by spectroscopic analyses and total synthesis. It was noteworthy that the purchased synthetic precursors, Fmoc-L- and Fmoc-D-MetO, were mixtures of epimers, respectively, due to the stereogenic sulfur atom in MetO, which were separated to prepare the optically pure isomers via the method of supercritical fluid chromatography (SFC). In addition, the other four optical isomers [(−)-1, (−)-2, (+)-4 and (−)-4] were also synthesized. Furthermore, (+)-1, (−)-1, (+)-3, (+)-4 and (−)-4 showed potential anti-Parkinson’s disease activities in an in vivo zebrafish model. Full article

Reliable taxonomy of biological producers is essential for finding new natural substances. A recent study morphologically re-examined 21 accessed vouchers to confirm multiple reported misidentifications and suggested marine sponges from the genus Rhabdastrella as the only known source of the isomalabaricane triterpenoids. The present study aimed to find isomalabaricane-containing sponges among the samples collected during seven marine expeditions to the Vietnam waters of the South China Sea, accompanied with their identification confirmed using morphological and molecular (18S rRNA and 28S rRNA) analyses. As a result, nine sponges identified as Rhabdastrella globostellata were found to contain isomalabaricanes in their extracts. A chemical investigation of the R. globostellata (PIBOC O63-136) specimen led to the isolation of nine isomalabaricane triterpenoids including the new compound 1, of which the chemical structure was elucidated based on HRESIMS and NMR data. Subsequently, a combination of LC–MS/MS, multivariate statistical analysis, and feature-based molecular networking was applied to detect, annotate, and characterize the isomalabaricane chemical diversity across the nine R. globostellata specimens. As a result, two primary chemotypes containing individual sets of annotated compounds were discovered within the Vietnamese population of this sponge. Moreover, obtained data showed a series of new extremely rare isomalabaricanes in R. globostellata extracts including nitrogen-containing metabolites and glycosides of this structural class. Full article

Xestoquinone derivatives isolated from marine sponges exhibit a range of bioactivities, including the inhibition of HIF signaling, mitochondrial function, and tumor cell proliferation. Mechanistic investigation suggested that 14-hydroxymethylxestoquinone (1) acts as a protonophore. Although adociaquinones A (5) and B (6) each stimulated cellular oxygen consumption, neither affected mitochondrial membrane potential. Cell-based respiration studies revealed that adociaquinones restored sodium azide-stalled oxygen consumption and ascorbate enhanced this response, suggesting ascorbate-supported redox cycling as a possible mechanism by which adociaquinones suppress HIF and tumor cell proliferation. These xestoquinone derivatives activated cellular stress response pathways that inhibit protein translation by phosphorylating key regulatory proteins (i.e., eIF2α, eIF4E, and eEF2). Further, thiol-reducing agents NAC and DTT attenuated the monosubstituted xestoquinone derivatives’ efficacy to inhibit HIF signaling, suggesting a potential mechanism of action that involves sulfhydryl modification. Full article

The crude ethyl acetate extract of the culture of a marine sponge-associated fungus, Aspergillus unguis KUFA 0098, was tested for its capacity to inhibit the growth of ten phytopathogenic fungi, viz. Alternaria brassicicola, Bipolaris oryzae, Colletotrichum capsici, Curvularia oryzae, Fusarium semitectum, Lasiodiplodia theobromae, Phytophthora palmivora, Pyricularia oryzae, Rhizoctonia oryzae, and Sclerotium roflsii. At a concentration of 1 g/L, the crude extract was most active against P. palmivora, causing the highest growth inhibition (55.32%) of this fungus but inactive against R. oryzae and S. roflsii. At a concentration of 10 g/L, the crude extract completely inhibited the growth of most of the fungi, except for L. theobromae, R. oryzae, and S. roflsii, with 94.50%, 74.12%, and 67.80% of inhibition, respectively. The crude extract of A. unguis KUFA 0098 exhibited growth-inhibitory effects against B. oryzae and P. oryzae, causative agents of brown leaf spot disease and leaf blast disease, respectively, on rice plant var. KDML105, under greenhouse conditions. Chromatographic fractionation and purification of the extract led to the isolation of four previously described depsidones, viz. unguinol (1), 2-chlorounguinol (2), 2,4-dichlorounguinol (3), and folipastatin (4), as well as one polyphenol, aspergillusphenol A (5). The major compounds, i.e., 1, 2, and 4, were tested against the ten phytopathogenic fungi. Compounds 1 and 4 were able to inhibit growth of most of the fungi, except L. theobromae, R. oryzae, and S. roflsii. Compound 1 showed the same minimum inhibitory concentration (MIC) values as that of carbendazim against A. brassicicola, C. capsici, C. oryzae, and P. oryzae, while compound 4 showed the same MIC values as that of carbendazim against only C. capsici and P. oryzae. Compound 2 was not active against all of the ten phytopathogenic fungi tested. Full article

Coral reefs are crucial ecosystems for marine biodiversity but are increasingly threatened by anthropogenic pressures and climate anomalies. The 2016 global bleaching event resulted in widespread coral mortality, altering reef structure and benthic communities. Here, we examine the evolution of Maldivian reefs from 2015 to 2023 using long-term monitoring data to assess post-disturbance dynamics. Analyses of 26 benthic descriptors revealed severe impacts from thermal stress, with heterogeneous recovery patterns. Reef-building capacity, which reflects the reef’s accretion potential and is mainly sustained by primary (e.g., Acropora branching corals) and secondary constructors (e.g., Tridacna spp.), rebounded substantially, while binders (e.g., coralline algae) and bafflers (e.g., erect sponges) remained depleted. Among growth forms, fast-growing branching and digitate corals, despite substantial declines, drove rapid recovery. Massive corals were less affected and continued growing, while encrusting corals declined steadily over the period. Post-bleaching community composition shifted markedly toward increased abiotic cover and reduced coral dominance, with partial reversion by 2023. Despite the 2016 collapse in constructional capacity, most reefs exhibited notable recovery within seven years. These findings underscore the moderate yet promising resilience of Maldivian reefs, exceeding previous bleaching events, and emphasize the importance of long-term monitoring to understand ecosystem responses under accelerating climate stress. Full article

Coralligenous assemblages are among the most diverse habitats of the Mediterranean Sea, yet those of the north-eastern basin remain understudied despite their vulnerability to human impacts and climate change. We applied a multimodal underwater sensing approach to map coralligenous formations, assess gorgonian populations and evaluate the effects of marine litter in a conservation-priority area (NE Aegean Sea, Greece). Side-scan sonar enabled seafloor mapping and guided targeted Remotely Operated Vehicle (ROV) surveys. ROV-based distance sampling and imagery provided quantitative data on Eunicella cavolini and Paramuricea clavata, including density, size structure, and injuries, alongside systematic documentation of marine litter. Gorgonians formed monospecific ecological facies, segregated by location—P. clavata occurred deeper than E. cavolini. Densities were low (E. cavolini: 0.35 colonies m⁻², P. clavata: 1.46 colonies m⁻²) and small colonies (<10 cm) were rare, suggesting limited recruitment. However, the presence of large colonies indicates stable environmental conditions that support long-term persistence, as reproductive output increases with colony size. Colony injuries were minor, but marine litter was abundant, dominated by fishing lines and ropes entangled with gorgonians and sponges. These findings highlight the value of acoustic–optical integration for non-destructive monitoring and provide essential baselines for conservation under EU directives. Full article

Although marine sponges display strikingly diverse colors, the molecular basis of this color diversity remains largely unknown. Recently, the blue coloration of Haliclona sp. was attributed to a water-soluble carotenoprotein that binds orange astaxanthin (AXT) and mytiloxanthin (MXT) and belongs to the ependymin superfamily. Here, we investigated the coloration mechanism of a purple sponge, Haliclona sp. The purified purple protein was identified as a secreted glycoprotein, representing the second example of a color protein belonging to the ependymin superfamily. The blue and purple proteins were accordingly designated carotenoependymin (Cep)-Blue1 and Cep-Purple1. Cep-Blue1 binds orange AXT and MXT in a 1:1 ratio, whereas Cep-Purple1 binds only AXT, producing a smaller red shift than Cep-Blue1 in the 550–750 nm range. In vitro reconstitution of carotenoid-free apoproteins with their native carotenoids reproduced the original spectra. When the carotenoids bound to Cep-Blue1 and Cep-Purple1 were exchanged and reconstituted in vitro, Cep-Blue1 reconstituted with AXT exhibited a purplish-blue color, whereas Cep-Purple1 reconstituted with an equimolar mixture of AXT and MXT showed a preference for AXT and displayed an incomplete red shift. These results suggest that the subtle color variations among Haliclona species are determined by both species-specific carotenoid composition and the structural features of carotenoependymin proteins. Full article

Alzheimer’s disease continues to be one of the most urgent neurodegenerative conditions, with acetylcholinesterase (AChE) inhibitors serving as a fundamental component of contemporary treatment approaches. Growing evidence underscores that marine ecosystems are a rich source of structurally varied and biologically active natural products exhibiting anticholinesterase properties. This review presents a thorough synthesis of marine-derived metabolites—including those sourced from bacteria, fungi, sponges, algae, and other marine life—that demonstrate inhibitory effects against AChE and butyrylcholinesterase (BuChE). Numerous compounds, such as meroterpenoids, alkaloids, peptides, and phlorotannins, not only show nanomolar to micromolar inhibitory activity but also reveal additional neuroprotective characteristics, including antioxidant effects, anti-amyloid properties, and modulation of neuronal survival pathways. Despite these encouraging findings, the transition to clinical applications is hindered by a lack of comprehensive pharmacokinetic, toxicity, and long-term efficacy studies. The structural variety of marine metabolites provides valuable frameworks for the development of next-generation cholinesterase inhibitors. Further interdisciplinary research is essential to enhance their therapeutic potential and facilitate their incorporation into strategies for addressing Alzheimer’s disease and related conditions. Full article