Development of cellulose acetate poly acrylonitrile (CAPA)-SiC/epoxy coating to mitigate corrosion of copper in chloride containing solutions.

A new conducting polymer of the cellulose acetate poly acrylonitrile (CAPA)-SiC composite was produced using an in situ oxidative polymerization technique in an aqueous medium. SiC was synthesized from Cinachyrella sp. as a source of carbon and silicon at 1200 °C under an argon atmosphere via a catalytic reduction process. The structure and morphology of the CAPA-SiC composite were characterized using surface area studies (BET), X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FT-IR), and surface morphology (SEM & TEM). To protect copper, the produced CAPA-SiC composite was mixed with commercial epoxy paint using a casting technique, and the copper surface was coated with the three components of the CAPA-SiC/epoxy paint mixture. The corrosion inhibition improvement of the CAPA-SiC/paint coating was assessed using electrochemical impedance spectroscopy followed by Tafel polarization measurements in a 3.5 wt% NaCl solution. The corrosion protection ability of the CAPA-SiC/epoxy coating was found to be outstanding at 97.4% when compared to that of a CAPA/paint coating. SEM and XRD were used to illustrate the coating on the copper surface.

Structural insights and antimicrobial synergy of a proto-galectin from the marine sponge Aiolochroia crassa.

In this study, we isolated a novel lectin from the marine sponge Aiolochroia crassa, named AcrL. The lectin showed a preference for glycans containing sialic acid terminal residues, as indicated by the strongest inhibition with fetuin and bovine submaxillary mucin. Primary structure determination by mass spectrometry revealed that AcrL is a galectin with conserved amino acid residues typically involved in carbohydrate binding. Structural modeling indicated that AcrL adopts a typical galectin ß-sandwich motif, featuring two anti-parallel ß-sheets with five strands each. Docking calculations revealed a carbohydrate-binding site composed of a main site, capable of hosting galactopyranosides, and an extended site, facilitating the binding of complex carbohydrates. AcrL inhibited significant biofilm formation against Staphylococcus aureus, S. epidermidis, and Escherichia coli with concentrations ranging from 500 to 15.6 µg.mL-1 for S. aureus, 7.8 µg.mL-1 for S. epidermidis, and 500 µg.mL-1 for E. coli. Furthermore, when combined with different antibiotics, AcrL potentiated their effect against pathogenic bacteria. The antimicrobial mechanism of AcrL was investigated using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The analysis indicates that AcrL induces damage to the bacterial membrane. These findings underscore the discovery of a novel galectin in a basal organism and the comprehensive biochemical characterization conducted in this research, highlighting the potential of AcrL as a novel antibacterial agent and emphasizing its importance in combating bacterial infections.

Genomic insights into symbiosis and host adaptation of sponge-associated novel bacterium, Rossellomorea orangium sp. nov.

Sponge-associated microorganisms play vital roles in marine sponge ecology. This study presents a genomic investigation of Rossellomorea sp. MCCB 382, isolated from Stelletta sp., reveals insights into its adaptations and symbiotic roles. Phylogenomic study and Overall Genomic Relatedness Index (OGRI) classify MCCB 382 as a novel species, Rossellomorea orangium sp. nov. The genome encodes numerous carbohydrate metabolism enzymes (CAZymes), likely aiding nutrient cycling in the sponge host. Unique eukaryotic-like protein domains hint at potential mechanisms of symbiosis. Defense mechanisms include CRISPR, restriction modification systems, DNA phosphorothioation, toxin-antitoxin systems, and heavy metal and multidrug resistance genes, indicating adaptation to challenging marine environments. Unlike obligate mutualists, MCCB 382 shows no genome reduction. Furthermore, the presence of mobile genetic elements, horizontal gene transfer, and prophages suggest genetic versatility, implying flexible metabolic potential and capacity for rapid adaptation and symbiosis shifts. MCCB 382 possesses six biosynthetic gene clusters for secondary metabolites, including both type II and III polyketide synthases (PKS), terpenes, (NRPS), NRPS-independent-siderophore, and lassopeptide. Further genome mining using BiGScape revealed four distinct gene cluster families, T2PKS, NRPS-independent-siderophore, lasso peptide, and terpene, presenting opportunities for novel compound elucidation. Our study reveals a symbiotic lifestyle of MCCB 382 with the host sponge, highlighting symbiont factors that aid in establishing and sustaining this relationship. This is the pioneering genomic characterisation of a novel Rossellomorea sp. within the sponge Stelletta sp. holobiont.

Microbulbifer spongiae sp. nov., isolated from marine sponge Diacarnus erythraeanus.

A novel bacterium, designated as MI-GT, was isolated from marine sponge Diacarnus erythraeanus. Cells of strain MI-GT are Gram-stain-negative, aerobic, and rod or coccoid-ovoid in shape. MI-GT is able to grow at 10-40 °C (optimum, 28 °C), with 1.0-8.0% (w/v) NaCl (optimum, 4.0%), and at pH 5.5-9.0 (optimum, pH 8.0). The 16S rRNA gene sequence of strain MI-GT shows 98.35, 97.32 and 97.25% similarity to those of Microbulbifer variabilis Ni-2088T, Microbulbifer maritimus TF-17T and Microbulbifer echini AM134T, respectively. Phylogenetic analysis also exhibits that strain MI-GT falls within a clade comprising members of the genus Microbulbifer (class Gammaproteobacteria). The genome size of strain MI-GT is 4478124 bp with a G+C content of 54.51 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MI-GT and other type strains are 71.61-76.44% (ANIb), 83.27-84.36% (ANIm) and 13.4-18.7% (dDDH), respectively. These values are significantly lower than the recommended threshold values for bacterial species delineation. Percentage of conserved proteins and average amino acid identity values among the genomes of strain MI-GT and other closely related species are 52.04-59.13% and 67.47-77.21%, respectively. The major cellular fatty acids of MI-GT are composed of summed feature 8 (C18 : 1 ω7c or C18 : 1 ω6c), iso-C11 : 0 3-OH, iso-C15 : 0, C16 : 0, and summed feature 9 (C17 : 1 iso ω9c or C16 : 0 10-methyl). The polar lipids of MI-GT mainly consist of phosphatidylethanolamine, phosphatidylglycerol, aminolipid, and two glycolipids. The major respiratory quinone is Q-8. Based on differential phenotypic and phylogenetic data, strain MI-GT is considered to represent a novel species of genus Microbulbifer, for which the name Microbulbifer spongiae sp. nov. is proposed. The type strain is MI-GT (=MCCC 1K07826T=KCTC 8081T).

Selection of marine bacterial consortia efficient at degrading chitin leads to the discovery of new potential chitin degraders.

Chitin degradation is a keystone process in the oceans, mediated by marine microorganisms with the help of several enzymes, mostly chitinases. Sediment, seawater, and filter-feeding marine invertebrates, such as sponges, are known to harbor chitin-degrading bacteria and are presumably hotspots for chitin turnover. Here, we employed an artificial selection process involving enrichment cultures derived from microbial communities associated with the marine sponge Hymeniacidon perlevis, its surrounding seawater and sediment, to select bacterial consortia capable of degrading raw chitin. Throughout the artificial selection process, chitin degradation rates and the taxonomic composition of the four successive enrichment cultures were followed. To the best of our knowledge, chitin degradation was characterized for the first time using size exclusion chromatography, which revealed significant shifts in the numbered average chitin molecular weight, strongly suggesting the involvement of endo-chitinases in the breakdown of the chitin polymer during the enrichment process. Concomitantly with chitin degradation, the enrichment cultures exhibited a decrease in alpha diversity compared with the environmental samples. Notably, some of the dominant taxa in the enriched communities, such as Motilimonas, Arcobacter, and Halarcobacter, were previously unknown to be involved in chitin degradation. In particular, the analysis of published genomes of these genera suggests a pivotal role of Motilimonas in the hydrolytic cleavage of chitin. This study provides context to the microbiome of the marine sponge Hymeniacidon perlevis in light of its environmental surroundings and opens new ground to the future discovery and characterization of novel enzymes of marine origin involved in chitin degradation processes.IMPORTANCEChitin is the second most abundant biopolymer on Earth after cellulose, and the most abundant in the marine environment. At present, industrial processes for the conversion of seafood waste into chitin, chitosan, and chitooligosaccharide (COS) rely on the use of high amounts of concentrated acids or strong alkali at high temperature. Developing bio-based methods to transform available chitin into valuable compounds, such as chitosan and COS, holds promise in promoting a more sustainable, circular bioeconomy. By employing an artificial selection procedure based on chitin as a sole C and N source, we discovered microorganisms so-far unknown to metabolize chitin in the rare microbial biosphere of several marine biotopes. This finding represents a first important step on the path towards characterizing and exploiting potentially novel enzymes of marine origin with biotechnological interest, since products of chitin degradation may find applications across several sectors, such as agriculture, pharmacy, and waste management.

One New Quinazoline-Containing Diketopiperazine Isolated from the Marine-Sponge-Derived Fungus Penicillium sp. SCSIO41043.

One new quinazoline-containing diketopiperazine (1), along with 24 known compounds including nine alkaloids (2-9, and 25), thirteen lactones (10-22), aspterric acid (23), and catechol (24), were isolated from the marine sponge-derived Penicillium sp. SCSIO41043. Their planar structures were unequivocally elucidated by spectroscopic analysis. The absolute configuration of 1 was determined by a comparison of reported and experimental electronic circular dichroism (ECD) spectra. Compound 16 was found to notably inhibit the growth of five pathogenic bacteria and fungi with MIC values ranging from 0.5-16.0 µg/mL. Compounds 7, 17, 20, and 22 demonstrated moderate activity against Micrococcus luteus with MIC values ranging from 35.6 to 71.1 µg/mL. Moreover, 1-3 displayed different degrees of antioxidant activity with EC50 values of 0.98, 0.60, 0.46 mg/mL, respectively.

Metagenomic Insights Reveal Unrecognized Diversity of Entotheonella in Japanese Theonella Sponges.

Numerous biologically active natural products have been discovered from marine sponges, particularly from Theonella swinhoei, which is known to be a prolific source of natural products such as polyketides and peptides. Recent studies have revealed that many of these natural products are biosynthesized by Candidatus Entotheonella phylotypes, which are uncultivated symbionts within T. swinhoei. Consequently, Entotheonella is considered an untapped biochemical resource. In this study, we conducted metagenomic analyses to assess the diversity of Entotheonella in two T. swinhoei Y and two T. swinhoei W (Y and W referring to the yellow and white interior of the sponge, respectively), after separating filamentous bacteria using density gradient centrifugation. We obtained five Entotheonella metagenome-assembled genomes (MAGs) from filamentous bacteria-enriched fractions. Notably, one of these MAGs is significantly different from previously reported Entotheonella variants. Additionally, we identified closely related Entotheonella members present across different chemotypes of T. swinhoei. Thus, our metagenomic insights reveal that the diversity of Entotheonella within Theonella sponges is greater than previously recognized.

Pyrrololactam alkaloids with IL-6 inhibitory activities from the sponge Phakellia fusca collected in the South China Sea.

Sixteen undescribed pyrrololactam alkaloids, including five 2-bromopyrrole-ε-lactam (1a, 1b, 4a, 4b and 5), two 3-bromopyrrole-ε-lactam (9 and 10), eight pyrrole-ε-lactam (2a-3 and 6a-8), and one pyrrole-δ-lactam alkaloids (11), along with three previously reported compounds (12-14) were isolated from the marine sponge Phakellia fusca collected in the South China Sea. The planar structures were determined by NMR and MS analyses, while the absolute configurations were clearly elucidated by comparing the experimental and calculated ECD spectra. Compounds 2a, 2b, 4a-7b, 10, 12 and 13 exhibited anti-inflammatory activity in inhibiting the production of inflammatory cytokines IL-6 in LPS-induced RAW264.7 macrophages.

Metagenomic mining of two Egyptian Red Sea sponges associated microbial community.

The Red Sea is a promising habitat for the discovery of new bioactive marine natural products. Sponges associated microorganisms represent a wealthy source of compounds with unique chemical structures and diverse biological activities. Metagenomics is an important omics-based culture-independent technique that is used as an effective tool to get genomic and functional information on sponge symbionts. In this study, we used metagenomic analysis of two Egyptian Red Sea sponges Hyrtios erectus and Phorbas topsenti microbiomes to study the biodiversity and the biosynthetic potential of the Red Sea sponges to produce bioactive compounds. Our data revealed high biodiversity of the two sponges' microbiota with phylum Proteobacteria as the most dominant phylum in the associated microbial community with an average of 31% and 70% respectively. The analysis also revealed high biosynthetic potential of sponge Hyrtios erectus microbiome through detecting diverse types of biosynthetic gene clusters (BGCs) with predicted cytotoxic, antibacterial and inhibitory action. Most of these BGCs were predicted to be novel as they did not show any similarity with any MIBiG database known cluster. This study highlights the importance of the microbiome of the collected Red Sea sponge Hyrtios erectus as a valuable source of new bioactive natural products.

Chengkuizengella axinellae sp. nov., a symbiotic bacterium isolated from a marine sponge of the genus Axinella.

A Gram-stain-positive, strictly aerobic, creamy-white colored, endospore-forming and non-motile rods strain, designated as strain 2205SS18-9T, was isolated from a marine sponge, Axinella sp. collected from Seopseom Island, Republic of Korea. Optimal growth of strain 2205SS18-9T was observed at 25-30 °C, pH 6.5-7.0, and in the presence of 3.0% (w/v) NaCl. Cells were oxidase-positive and catalase-negative. Negative for nitrate reduction and indole production. Phylogenetic analyses based on the 16S rRNA gene and whole-genome sequences revealed that strain 2205SS18-9T formed a distinct phyletic lineage in the genus Chengkuizengella, and it was most closely related to Chengkuizengella marina YPA3-1-1T and Chengkuizengella sediminis J15A17T with 97.1 and 96.6% 16S rRNA gene sequence similarities, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between strain 2205SS18-9T and Chengkuizengella marina YPA3-1-1T were 79.0 and 21.6%, respectively. The genomic DNA G + C content was 34.1%. The genome harbors a number of host-adhesion and transporter genes, suggested that strain 2205SS18-9T may interact with its sponge host as a symbiont. Menaquinone-7 was the sole isoprenoid quinone and antieiso-C15:0 (28.5%), iso-C16:0 (25.8%), C16:1 ω7c alcohol (15.0%), and iso-C15:0 (11.2%) were detected as the major fatty acids. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified aminophospholipids, and an unidentified lipid. The cell-wall peptidoglycan contained lysine, alanine, glutamate, and aspartate. Based on these analyses, strain 2205SS18-9T represents a novel species of the genus Chengkuizengella, for which the name Chengkuizengella axinellae sp. nov. is proposed. The type strain is 2205SS18-9T (= KACC 23238T = LMG 33063T).

Identification of Axinellamines A and B as Anti-Tubercular Agents.

Tuberculosis remains a significant global health pandemic. There is an urgent need for new anti-tubercular agents to combat the rising incidence of drug resistance and to offer effective and additive therapeutic options. High-throughput screening of a subset of the NatureBank marine fraction library (n = 2000) identified a sample derived from an Australian marine sponge belonging to the order Haplosclerida that displayed promising anti-mycobacterial activity. Bioassay-guided fractionation of the organic extract from this Haplosclerida sponge led to the purification of previously identified antimicrobial pyrrole alkaloids, axinellamines A (1) and B (2). The axinellamine compounds were found to have a 90% minimum inhibitory concentration (MIC90) of 18 µM and 15 µM, respectively. The removal of protein and complex carbon sources reduced the MIC90 of 1 and 2 to 0.6 and 0.8 µM, respectively. The axinellamines were not toxic to mammalian cells at 25 µM and significantly reduced the intracellular bacterial load by >5-fold. These data demonstrate that axinellamines A and B are effective anti-tubercular agents and promising targets for future medicinal chemistry efforts.

Marine sponge-derived alkaloid inhibits the PI3K/AKT/mTOR signaling pathway against diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous non-Hodgkin lymphoma that is extremely aggressive and has an intermediate to high malignancy. Some patients still experience treatment failure, relapse, or resistance to rituximab, cyclophosphamide, adriamycin, vincristine, and prednisone (R-CHOP) therapy. Therefore, there is an urgent need for further research on new agents for the treatment of DLBCL. AP-48 is an aaptamine alkaloid analog with potent anti-tumor effects that originates from marine natural products. In this study, we found that AP-48 exhibits dose-dependent cytotoxicity in DLBCL cell lines. Flow cytometry showed that AP-48 induced cell cycle arrest in the G0/G1 phase in SU-DHL-4 and Farage cells and in the S phase in WSU-DLCL-2 cells. AP-48 also accelerated apoptosis via the caspase-3-mediated intrinsic apoptotic pathway. Further experiments demonstrated that AP-48 exerted its anti-DLBCL effects through the PI3K/AKT/mTOR pathway, and that the PI3K agonist YS49 partially alleviated the inhibition of cell proliferation and apoptosis induced by AP-48. Finally, in a tumor xenograft model, AP-48 inhibited tumor growth and promoted apoptosis in tumor tissues, indicating its therapeutic potential in DLBCL.

Effects of plasticizer Di(2-ethylhexyl) phthalate (DEHP) on the microbiome of the marine sponge Hymeniacidon heliophila.

Marine pollution research in the last 15 years focused on an emerging anthropogenic contaminant: plastic debris and more specifically, microplastics. Since, not only its physical impacts on marine invertebrates were studied, but also its additives. Phthalate, a plasticizer commonly found in the ocean and known endocrine disruptor was already observed in different aquatic invertebrates, but few is known about its presence and possible effects in Porifera physiology. Our study aimed to analyze potential shifts in Hymeniacidon heliophila (Desmosponge) microbiome after exposure to Di(2-ethylhexyl) phthalate (DEHP), the most common phthalate found in the ocean, in three different doses for 4 and 24 h. Results indicate that alpha diversity had significantly changed between control and exposed organisms but not in all multicomparisons. Microbial community structure changed after exposure as well although most abundant phyla did not vary along the experiment. The core microbiome between control and each exposed organisms contained the vast majority of total ASVs and a few ASVs were exclusive to each experimental group. After DEHP exposure, microbial classes had significant changes and species with phthalate degradation enzymes were identified in a specifically dose dependent manner pointing to a possible bacterial consortium responsible for the phthalate degradation. The bacterial detoxification activity may lead to H. heliophila resistance during DEHP exposure in polluted environmental conditions.

A new 3,4-dinorsteroid from the marine sponge Cliona sp.

A new steroid, 2a-oxa-2-oxo-5ß-hydroxy-3,4-dinor-24-methylcholesta-22E-ene (1), together with 10 known ones (2-11), was isolated from the marine sponge Cliona sp. The structures of these compounds were determined by the spectroscopic methods (UV, IR, MS, and NMR) and X-ray diffraction analysis. Compound 1 was the third example of 3,4-dinorsteroid with a hemiketal at C-5 that was isolated from the natural source. In addition, the antibacterial activities of these compounds were also evaluated. However, none of them exhibited significant inhibition effects.

Chemical and Biological Characterization of the Ethyl Acetate Fraction from the Red Sea Marine Sponge Hymedesmia sp.

Hymedesmiidae is one of the largest families of marine sponges and stands out as an exceptional source of variable metabolites with diverse biological activities. In this study, the ethyl acetate fraction (HE) of a Hymedesmia sp. marine sponge from the Red Sea, Egypt, was analyzed for the first time using Ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) analysis. The analysis tentatively identified 29 compounds in this fraction, including the isolation and identification of six compounds (two pyrimidine nucleosides, one purine, and two pyrimidine bases in addition to one cerebroside) for the first time. The structures of the isolated compounds were established by 1D and 2D NMR (nuclear magnetic resonance), MS (mass spectrometry), and IR (infrared) spectroscopy. Furthermore, the cytotoxic, antioxidant, and antimicrobial activities of the ethyl acetate fraction were evaluated in vitro. The fraction exhibited strong DPPH scavenging activity with an IC50 of 78.7 µg/mL, compared to ascorbic acid as a positive control with an IC50 of 10.6 µg/mL. It also demonstrated significant cytotoxic activity with IC50 values of 13.5 µg/mL and 25.3 µg/mL against HCT-116 and HEP-2 cell lines, respectively, compared to vinblastine as a positive control with IC50 values of 2.34 µg/mL and 6.61 µg/mL against HCT-116 and HEP-2, respectively. Additionally, the ethyl acetate fraction displayed promising antibacterial activity against S. aureus with a MIC value of 62.5 µg/mL, compared to ciprofloxacin as a positive control with MIC values of 1.56 µg/mL for Gram-positive bacteria and 3.125 µg/mL for Gram-negative bacteria. It also exhibited activity against E. coli and P. aeruginosa with MIC values of 250 µg/mL and 500 µg/mL, respectively. Briefly, this is the first report on the biological activities and secondary metabolite content of the ethyl acetate fraction of Hymedesmia sp. marine sponge, emphasizing the potential for further research against resistant bacterial and fungal strains, as well as different cancer cell lines. The ethyl acetate fraction of Hymedesmia sp. is a promising source of safe and unique natural drugs with potential therapeutic and pharmaceutical benefits.

Halenaquinol Blocks Staphylococcal Protein A Anchoring on Cell Wall Surface by Inhibiting Sortase A in Staphylococcus aureus.

Sortase A (SrtA) is a cysteine transpeptidase that binds to the periplasmic membrane and plays a crucial role in attaching surface proteins, including staphylococcal protein A (SpA), to the peptidoglycan cell wall. Six pentacyclic polyketides (1-6) were isolated from the marine sponge Xestospongia sp., and their structures were elucidated using spectroscopic techniques and by comparing them to previously reported data. Among them, halenaquinol (2) was found to be the most potent SrtA inhibitor, with an IC50 of 13.94 µM (4.66 µg/mL). Semi-quantitative reverse transcription PCR data suggest that halenaquinol does not inhibit the transcription of srtA and spA, while Western blot analysis and immunofluorescence microscopy images suggest that it blocks the cell wall surface anchoring of SpA by inhibiting the activity of SrtA. The onset and magnitude of the inhibition of SpA anchoring on the cell wall surface in S. aureus that has been treated with halenaquinol at a value 8× that of the IC50 of SrtA are comparable to those for an srtA-deletion mutant. These findings contribute to the understanding of the mechanism by which marine-derived pentacyclic polyketides inhibit SrtA, highlighting their potential as anti-infective agents targeting S. aureus virulence.

Taking inspiration from the natural tubular sponge to enhance momentum exchange in marine environments.

Coral reefs consist of various alive elements with specific biological functions. Tubular sponges, as the main coral reefs' constituents, have a marvelous mechanism. They receive nutrients by suctioning from the perforated body (Ostia) and pumping the un-digested materials through the water column from the top mouth (Osculum). This mechanism can be an inspiration for making a device to control or improve sediment/pollutant transport. In the current study, an attempt has been made to evaluate an inspired concept's effects on flow hydrodynamics. In this regard, OpenFOAM® V. 1812 (interFOAM solver) and image processing technique were deployed. The perforated finite-height cylinders (height to diameter ratio of 2.5) with various suction/pump discharges (i.e., J = 150, 300, 350, 400, 450, and 600 lit/h) were considered. The results indicated that increasing the outflow discharge (J ≥ 600 lit/h) could widen the wake by flapping the shear layer. In the vertical plane, the results showed that dipole vortices turned into quadrupole vortex. On the free surface, tip-vortices and counter-rotating vortex pairs (CRVP) generated saw-toothed vortices on two sides of the cylinder. Generating these unique vortices is proof of enhancing the momentum exchange through the water column.

Unveiling antibiofilm potential: proteins from Priestia sp. targeting Staphylococcus aureus biofilm formation.

Staphylococcus aureus is the etiologic agent of many nosocomial infections, and its biofilm is frequently isolated from medical devices. Moreover, the dissemination of multidrug-resistant (MDR) strains from this pathogen, such as methicillin-resistant S. aureus (MRSA) strains, is a worldwide public health issue. The inhibition of biofilm formation can be used as a strategy to weaken bacterial resistance. Taking that into account, we analysed the ability of marine sponge-associated bacteria to produce antibiofilm molecules, and we found that marine Priestia sp., isolated from marine sponge Scopalina sp. collected on the Brazilian coast, secretes proteins that impair biofilm development from S. aureus. Partially purified proteins (PPP) secreted after 24 hours of bacterial growth promoted a 92% biofilm mass reduction and 4.0 µg/dL was the minimum concentration to significantly inhibit biofilm formation. This reduction was visually confirmed by light microscopy and Scanning Electron Microscopy (SEM). Furthermore, biochemical assays showed that the antibiofilm activity of PPP was reduced by ethylenediaminetetraacetic acid (EDTA) and 1,10 phenanthroline (PHEN), while it was stimulated by zinc ions, suggesting an active metallopeptidase in PPP. This result agrees with mass spectrometry (MS) identification, which indicated the presence of a metallopeptidase from the M28 family. Additionally, whole-genome sequencing analysis of Priestia sp. shows that gene ywad, a metallopeptidase-encoding gene, was present. Therefore, the results presented herein indicate that PPP secreted by the marine Priestia sp. can be explored as a potential antibiofilm agent and help to treat chronic infections.

Aaptamine-rich Fraction from the Indonesian Marine Sponge, Aaptos suberitoides, Exhibits a Cytotoxic Effect on DLD-1 Colorectal Cancer Cells.

OBJECTIVE: This study aimed to investigate the cytotoxicity effect of the ethyl acetate extract of Aaptos suberitoides on colorectal cancer cells (DLD-1) and murine fibroblast cells (NIH-3T3). METHODS: A. suberitoides was collected from Putus Island, Bunaken National Park, North Sulawesi, Indonesia, and was processed with maceration and ethyl acetate extraction. The sponge extract was characterized based on Thin Layer Chromatography (TLC) and then identified by using LCMS/MS analysis. DLD-1 and NIH-3T3 cells were treated with the ethyl acetate extract and then followed by 3- [4, 5-dimethylthiazol-2-yl] -2.5 diphenyl tetrazolium bromide (MTT) assay to assess their cytotoxicity effect. RESULTS: LCMS/MS analysis showed that the most abundant compounds in this extract were identified as aaptamine (1). Furthermore, this study revealed that the active ethyl acetate fraction of A. suberitoides has cytotoxic effects in colorectal cancer DLD-1 cells with an IC50 value of 9.597 µg/mL, higher than NIH-3T3 cells with an IC50 value of 12.23 µg/mL Thus, the active ethyl acetate fraction of A. suberitoides is considered more toxic to cancer cells than normal cells. CONCLUSION: This study provides the first evidence to support the role of the ethyl acetate extract of A. suberitoides sponge extracts to be developed as a colorectal anticancer agent.

Irciniaplysins A-D: New Psammaplysin Derivatives from Philippine Marine Sponge Ircinia sp.

Four new psammaplysin derivatives (1-4) with fatty acyl substituents, designated irciniaplysins A-D, and three known psammaplysins (5-7) were isolated from a marine sponge Ircinia sp. Their structures were elucidated using extensive spectroscopic analyses. The positions of the double bonds and the branch points of the fatty acyl side chains were determined by GC-MS analysis of their fatty acid methyl ester (FAME) derivatives. Irciniaplysins A (1) and B (2) contained an unusual long-chain fatty acyl substituent with a 5,9-diene unit. The isolated compounds were evaluated for their cytotoxic activity against the human colorectal carcinoma (HCT 116) cells, however, none of these compounds showed significant activity.