Sponge Research Articles

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.

A Screening of 10,240 NatureBank Fractions Identifies Nematicidal Activity in Agelasine-Containing Extracts from Sponges.

Nematode infections affect a fifth of the human population, livestock, and crops worldwide, imposing a burden to global public health and economies, particularly in developing nations. Resistance to commercial anthelmintics has increased over the years in livestock infections and driven the pursuit for new drugs. We herein present a rapid, cost-effective, and automated assay for nematicide discovery using the free-living nematode Caenorhabditis elegans to screen a highly diverse natural product library enriched in bioactive molecules. Screening of 10,240 fractions obtained from extracts of various biological sources allowed the identification of 7 promising hit fractions, all from marine sponges. These fractions were further assayed for nematicidal activity against the sheep nematode parasite Haemonchus contortus and for innocuity in zebrafish. The most active extracts against parasites and innocuous toward vertebrates belong to two chemotypes. High-performance liquid chromatography (HPLC) coupled with nuclear magnetic resonance (NMR) revealed that the most abundant compound in one chemotype is halaminol A, an aminoalcohol previously identified in a small screen against H. contortus. Terpene-nucleotide hybrids known as agelasines predominate in the other chemotype. This study reinforces the power of C. elegans for nematicide discovery from large collections and the potential of the chemical diversity derived from marine invertebrate biota.

Dynamics, diversity, and roles of bacterial transmission modes during the first asexual life stages of the freshwater sponge Spongilla lacustris

BackgroundSponge-associated bacteria play important roles in the physiology of their host, whose recruitment processes are crucial to maintain symbiotic associations. However, the acquisition of bacterial communities within freshwater sponges is still under explored. Spongilla lacustris is a model sponge widely distributed in European rivers and lakes, producing dormant cysts (named gemmules) for their asexual reproduction, before winter. Through an in vitro experiment, this study aims to describe the dynamics of bacterial communities and their transmission modes following the hatching of these gemmules.ResultsAn overall change of bacterial β-diversity was observed through the ontology of the juvenile sponges. These temporal differences were potentially linked, first to the osculum acquisition and the development of a canal system, and then, the increasing colonization of the Chlorella-like photosymbionts. Gemmules hatching with a sterilized surface were found to have a more dispersed and less diverse microbiome, revealing the importance of gemmule epibacteria for the whole holobiont stability. These epibacteria were suggested to be vertically transmitted from the maternal tissues to the gemmule surface. Vertical transmission through the incorporation of bacterial communities inside of the gemmule, was also found as a dominant transmission mode, especially with the nitrogen fixers Terasakiellaceae. Finally, we showed that almost no ASVs were shared between the free-living community and the juveniles, suggesting that horizontal recruitment is unlikely to happen during the first stages of development. However, the free-living bacteria filtered are probably used as a source of nutrients, allowing an enrichment of copiotrophic bacteria already present within its microbiome.ConclusionsThis study brings new insight for a better understanding of the microbiome acquisition during the first stages of freshwater sponge development. We showed the importance of epibacterial communities on gemmules for the whole holobiont stability, and demonstrated the near absence of recruitment of free-living bacteria during the first stages.

Marcytoglobosins A and B, Cytochalasans From a Marine Sponge Associated Chaetomium globosum 162105 Fungus.

Two new cytochalasans, marcytoglobosins A (1) and B (2) were isolated from the marine sponge associated fungus Chaetomium globosum 162105, along with six known compounds (3-8). The complete structures of two new compounds were determined based on 1D/2D NMR and HR-MS spectroscopic analyses coupled with ECD calculations. All eight isolates were evaluated for their antibacterial activity. Among them, compounds 3-8 displayed antibacterial effects against Staphylococcus epidermidis, Bacillus thuringiensis, Pseudomonas syringae pv. Actinidiae, Vibrio alginolyticus, and Edwardsiella piscicida with minimum inhibitory concentration (MIC) values ranging from 10 to 25 μg/mL.

Previously unknown diversity: the marine sponge (Porifera) fauna from Rio Grande do Norte State, NE Brazil

Previously unknown diversity: the marine sponge (Porifera) fauna from Rio Grande do Norte State, NE Brazil

Engineered bacteria that self-assemble "bioglass" polysilicate coatings display enhanced light focusing.

Photonic devices are cutting-edge optical materials that produce narrow, intense beams of light, but their synthesis typically requires toxic, complex methodology. Here we employ a synthetic biology approach to produce environmentally-friendly, living microlenses with tunable structural properties. We engineered Escherichia coli bacteria to display the silica biomineralization enzyme silicatein from aquatic sea sponges. Our silicatein-expressing bacteria can self-assemble a shell of polysilicate "bioglass" around themselves. Remarkably, the polysilicate-encapsulated bacteria can focus light into intense nanojets that are nearly an order of magnitude brighter than unmodified bacteria. Polysilicate-encapsulated bacteria are metabolically active for up to four months, potentially allowing them to sense and respond to stimuli over time. Our data demonstrate that engineered bacterial particles have the potential to revolutionize the development of multiple optical and photonic technologies.

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.

Red Sea Sponge Callyspongia siphonella Extract Induced Growth Inhibition and Apoptosis in Breast MCF-7 and Hepatic HepG-2 Cancer Cell Lines in 2D and 3D Cell Cultures.

The increasing incidence of cancer diseases necessitates the urgent exploration of new bioactive compounds. One of the trends in drug discovery is marine sponges which is gaining significant support due to the abundant production of natural pharmaceutical compounds obtained from marine ecosystems. This study evaluates the anticancer properties of an organic extract from the Red Sea sponge Callyspongia siphonella (C. siphonella) on HepG-2 and MCF-7 cancer cell lines. C. siphonella was collected, freeze-dried, and extracted using a methanol-dichloromethane mixture. The extract was analyzed via Liquid Chromatography-Mass Spectrometry. Cytotoxic effects were assessed through cell viability assays, apoptosis detection, cell cycle analysis, mitochondrial membrane potential assays, scratch-wound healing assays, and 3D cell culture assays. Fifteen compounds were identified in the C. siphonella extract. The extract showed moderate cytotoxicity against MCF-7 and HepG-2 cells, with IC50 values of 35.6 ± 6.9 μg/mL and 64.4 ± 8 μg/mL, respectively, after 48 hours of treatment. It induced cell cycle arrest at the G2/M phase in MCF-7 cells and the S phase in HepG-2 cells. Apoptosis increased significantly in both cell lines, accompanied by reduced mitochondrial membrane potential. The extract inhibited cell migration, with notable reductions after 24 and 48 hours. In 3D cell cultures, the extract had IC50 values of 5.1 ± 2 μg/mL for MCF-7 and 166.4 ± 27 μg/mL for HepG-2 after 7 days of treatment, showing greater potency in MCF-7 spheres compared to HepG-2 spheres. The anticancer activity is attributed to the bioactive compounds. The C. siphonella extract's ability to induce apoptosis, disrupt mitochondrial membrane potential, and arrest the cell cycle highlights its potential as a novel anticancer agent. Additional research is required to investigate the underlying mechanism by which this extract functions as a highly effective anticancer agent.

Multicentric retrospective study on the treatment characteristics, efficacy and safety of eribulin in Slovenian patients with breast cancer.

e13123 Background: Eribulin mesylate (eribulin) is a microtubule inhibitor and a synthetic analog of halichondrin B, a natural product isolated from the marine sponge Halichondria okadai. Eribulin was approved based on the randomized Phase 3 EMBRACE clinical trial, which showed an improvement in survival compared to chemotherapy (CT) of the physician's choice. The efficacy and safety of eribulin treatment in real-world settings has been reported in several studies: Korean and Chinese multicenter retrospective studies and a meta-analysis from 2020. Methods: We included all patients treated with eribulin between January 24, 2013 and September 14, 2022 at the Institute of Oncology Ljubljana (85.4% of patients) and University Medical Centre Maribor (14.6%). Clinical data were collected retrospectively from paper and electronic patient records. The primary endpoints were median progression-free survival (PFS), overall survival (OS), response rates and safety. We performed a descriptive statistical analysis and a survival analysis using the Kaplan-Meier method. Results: 205 patients, whose average age was 58.6 (29-88) years, were included in the study. The majority (79%) had a hormone receptor (HR+) positive tumor, 12.2% were HER2 positive and 16.6% were triple negative. 32/205 (15.6%) were primary metastatic. Of the remaining 173 patients, 160/173 (92.4%) received adjuvant therapy, of which 15% received hormone therapy, 23.1% received CT and 61.9% received both. At the start of treatment with eribulin, 84.9% had visceral tumors and 14.6% had tumors in the CNS. The median number of all treatment lines was 6 (range 2–15) and the median number of CT lines was 4 (0–13). The ECOG performance status was: 0 in 4.9%, 1 in 53.2%, 2 in 35.1% and 3 in 4.9% and 4 in 0.5% of patients. The objective response rate was 7.3% and clinical benefit was achieved in 27.3%. The median CT line in which eribulin was used was the fourth (1–10). Eribulin was used as the last CT line in half of the patients. The median PFS was 3.01 months (95% confidence interval 2.56–3.47) and the median OS was 6.68 months (95% confidence interval 5.60–7.77). Patients who received eribulin in the first 3 lines of treatment had a better OS than those who received eribulin in later lines. Adverse events (AEs) occurred in 52.7%. Eribulin therapy was discontinued due to AEs in 18.5% of patients. The most common AE was fatigue (25.9%), followed by neuropathy and neutropenia (22.9% and 18%). Conclusions: In our retrospective analysis, we found significantly worse results of treatment with eribulin than in previous studies. In our population, eribulin was used in the late stages of treatment and in older patients with poorer performance status. The proportion of patients with visceral and CNS tumors was higher. The side effects were comparable.

Identification and expression of MarCE, a marine carboxylesterase with synthetic ester-degrading activity.

Carboxylic ester hydrolases with the capacity to degrade polyesters are currently highly sought after for their potential use in the biological degradation of PET and other chemically synthesized polymers. Here, we describe MarCE, a carboxylesterase family protein identified via genome mining of a Maribacter sp. isolate from the marine sponge Stelligera stuposa. Based on phylogenetic analysis, MarCE and its closest relatives belong to marine-associated genera from the Cytophaga-Flavobacterium-Bacteroides taxonomic group and appear evolutionarily distinct to any homologous carboxylesterases that have been studied to date in terms of structure or function. Molecular docking revealed putative binding of BHET, a short-chain PET derivative, onto the predicted MarCE three-dimensional structure. The synthetic ester-degrading activity of MarCE was subsequently confirmed by MarCE-mediated hydrolysis of 2 mM BHET substrate, indicated by the release of its breakdown products MHET and TPA, which were measured, respectively, as 1.28 and 0.12 mM following 2-h incubation at 30°C. The findings of this study provide further insight into marine carboxylic ester hydrolases, which have the potential to display unique functional plasticity resulting from their adaptation to complex and fluctuating marine environmentsw.

Combined inhibition of class 1-PI3K-alpha and delta isoforms causes senolysis by inducing p21WAF1/CIP1 proteasomal degradation in senescent cells

The targeted elimination of radio- or chemotherapy-induced senescent cells by so-called senolytic substances represents a promising approach to reduce tumor relapse as well as therapeutic side effects such as fibrosis. We screened an in-house library of 178 substances derived from marine sponges, endophytic fungi, and higher plants, and determined their senolytic activities towards DNA damage-induced senescent HCT116 colon carcinoma cells. The Pan-PI3K-inhibitor wortmannin and its clinical derivative, PX-866, were identified to act as senolytics. PX-866 potently induced apoptotic cell death in senescent HCT116, MCF-7 mammary carcinoma, and A549 lung carcinoma cells, independently of whether senescence was induced by ionizing radiation or by chemotherapeutics, but not in proliferating cells. Other Pan-PI3K inhibitors, such as the FDA-approved drug BAY80-6946 (Copanlisib, Aliqopa®), also efficiently and specifically eliminated senescent cells. Interestingly, only the simultaneous inhibition of both PI3K class I alpha (with BYL-719 (Alpelisib, Piqray®)) and delta (with CAL-101 (Idelalisib, Zydelig®)) isoforms was sufficient to induce senolysis, whereas single application of these inhibitors had no effect. On the molecular level, inhibition of PI3Ks resulted in an increased proteasomal degradation of the CDK inhibitor p21WAF1/CIP1 in all tumor cell lines analyzed. This led to a timely induction of apoptosis in senescent tumor cells. Taken together, the senolytic properties of PI3K-inhibitors reveal a novel dimension of these promising compounds, which holds particular potential when employed alongside DNA damaging agents in combination tumor therapies.

Probing the Antiplasmodial Properties of Plakortinic Acids C and D: An Uncommon Pair of Marine Peroxide-Polyketides Isolated from a Two-Sponge Association of Plakortis symbiotica and Xetospongia deweerdtae Collected near Puerto Rico.

Plakortinic acids C (1) and D (2), an unseparable pair of endoperoxide polyketides isolated and purified from the symbiotic association of Caribbean Sea sponges Plakortis symbiotica-Xestospongia deweerdtae, underwent in vitro evaluation for antiplasmodial activity against the malaria parasite Plasmodium berghei using a drug luminescence assay. Initial screening at 10 µM revealed 50% in vitro parasite growth inhibition. The title compounds displayed antiplasmodial activity with an EC50 of 5.3 µM toward P. berghei parasites. The lytic activity against erythrocytes was assessed through an erythrocyte cell lysis assay, which showed non-lytic activity at lower concentrations ranging from 1.95 to 3.91 µM. The antiplasmodial activity and the absence of hemolytic activity support the potential of plakortinic acids C (1) and D (2) as promising lead compounds. Moreover, drug-likeness (ADMET) properties assessed through the pkCSM server predicted high intestinal absorption, hepatic metabolism, and volume of distribution, indicating favorable pharmacokinetic profiles for oral administration. These findings suggest the potential suitability of these metabolites for further investigations of antiplasmodial activity in multiple parasitic stages in the mosquito and Plasmodium falciparum. Notably, this study represents the first report of a marine natural product exhibiting the unique 7,8-dioxatricyclo[4.2.2.02,5]dec-9-ene motif being evaluated against malaria.

Characterization of antibiofilm compound from marine sponge Stylissa carteri.

The fouling phenomenon grabbed global attention and caused huge economic losses specifically in marine-related industries. Sessile behavior exposed the sponge to the risk of fouling. However, their bodies remained free from foulers, which were attributed to the chemical defense system. The objectives of this study were to determine the antibiofilm activity of the marine sponge, Stylissa carteri, and to characterize the isolated compound involved. The antibiofilm activity of S. carteri methanolic crude extract (MCE) and fractions was tested against biofilm-producing bacteria, Pseudomonas aeruginosa, using two different modes of crystal violet biofilm assays: preventive and detachment. Besides that, the disc-diffusion test was conducted to screen the antibacterial activity against gram-positive and gram-negative bacteria while a cytotoxicity assay was conducted on the HepG2 cell line. Bioassay-guided fractionation was carried out using vacuum liquid chromatography (VLC) and solid phase extraction using a C18 Sep-Pak Cartridge. The crystal compound was isolated and characterized through thin-layer chromatography (TLC), Fourier transform infrared (FTIR) spectroscopy, liquid chromatography-mass spectrometry (LCMS), and nuclear magnetic resonance (NMR) spectroscopy. The S. carteri MCE showed a promising result with a half-maximal inhibitory concentration (IC50) of 20.22μg/mL in the preventive assay, while no IC50 was determined in the detachment assay since all inhibitions < 50%. The S. carteri MCE exhibited broad-spectrum antibacterial activity and displayed a non-cytotoxic effect. Fraction 4 from MCE of S. carteri (IC50 = 2.40μg/mL) reduced the biofilm in the preventive assay at all concentrations and exhibited no antibacterial activity indicating the independence of antibiofilm from antibacterial properties. Based on the data obtained, an alkaloid named debromohymenialdisine (DBH) was identified from Fraction 4 of S. carteri MCE. In conclusion, S. carteri was able to reduce the establishment of the biofilm formed by P. aeruginosa and could serve as a prominent source of natural antifouling agents.

Synthesis and new DNA targeting activity of 6- and 7-tert-butylfascaplysins

Fascaplysin is a red cytotoxic pigment with anticancer properties isolated from the marine sponge Fascaplysinopsis sp. Recently, structure–activity relationship analysis reported by our group suggested that selective cytotoxicity of fascaplysin derivatives towards tumor cells negatively correlates with their ability to intercalate into DNA. To validate this hypothesis, we synthesized 6- and 7-tert-butylfascaplysins which reveal mitigated DNA-intercalating properties. These derivatives were found to be strongly cytotoxic to drug-resistant human prostate cancer cells, albeit did not demonstrate improved selectivity towards cancer cells when compared to fascaplysin. At the same time, kinome analysis suggested an activation of CHK1/ATR axis in cancer cells shortly after the drug exposure. Further experiments revealed induction of replication stress that is eventually converted to the toxic DNA double-strand breaks, resulting in caspase-independent apoptosis-like cell death. Our observations highlight new DNA-targeting effect of some fascaplysin derivatives and indicate more complex structure–activity relationships within the fascaplysin family, suggesting that cytotoxicity and selectivity of these alkaloids are influenced by multiple factors. Furthermore, combination with clinically-approved inhibitors of ATR/CHK1 as well as testing in tumors particularly sensitive to the DNA damage should be considered in further studies.

Methanolic Extract and Brominated Compound from the Brazilian Marine Sponge Aplysina fulva Are Neuroprotective and Modulate Inflammatory Profile of Microglia.

Neurodegenerative diseases involve neuroinflammation and a loss of neurons, leading to disability and death. Hence, the research into new therapies has been focused on the modulation of the inflammatory response mainly by microglia/macrophages. The extracts and metabolites of marine sponges have been presented as anti-inflammatory. This study evaluated the toxicity of an extract and purified compound from the Brazilian marine sponge Aplysina fulva as well as its neuroprotection against inflammatory damage associated with the modulation of microglia response. PC12 neuronal cells and neonatal rat microglia were treated with the methanolic extract of A. fulva (AF-MeOH, 0.1-200 μg/mL) or with its purified dimethyl ketal of 3,5-dibromoverongiaquinol (AF-H1, 0.1-100 μM). Cytotoxicity was determined by MTT tetrazolium, Trypan blue, and propidium iodide; microglia were also treated with the conditioned medium (CM) from PC12 cells in different conditions. The microglia phenotype was determined by the expression of Iba-1 and CD68. AF-MeOH and AF-H1 were not toxic to PC12 or the microglia. Inflammatory damage with Escherichia coli lipopolysaccharide (LPS, 5 μg/mL) was not observed in the PC12 cells treated with AF-MeOH (1-10 μg/mL) or AF-H1 (1-10 μM). Microglia subjected to the CM from PC12 cells treated with LPS and AF-MeOH or AF-H1 showed the control phenotype-like (multipolar, low-CD68), highlighting the anti-neuroinflammatory and neuroprotective effect of components of this marine sponge.

Onnamide A suppresses the severe acute respiratory syndrome-coronavirus 2 infection without inhibiting 3-chymotrypsin-like cysteine protease.

Given the continuous emergence of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the development of new inhibitors is necessary to enhance clinical efficacy and increase the options for combination therapy for the coronavirus disease 2019. Because marine organisms have been a resource for the discovery of numerous bioactive molecules, we constructed an extract library of marine invertebrates collected from the Okinawa Islands. In this study, the extracts were used to identify antiviral molecules against SARS-CoV-2. Using a cytopathic effect (CPE) assay in VeroE6/TMPRSS2 cells, an extract from the marine sponge Theonella swinhoei was found to reduce virus-induced CPE. Eventually, onnamide A was identified as an antiviral compound in the extract using column chromatography and NMR analysis. Onnamide A inhibited several SARS-CoV-2 variant-induced CPEs in VeroE6/TMPRSS2 cells as well as virus production in the supernatant of infected cells. Moreover, this compound blocked the entry of SARS-CoV-2 pseudo-virions. Taken together, these results demonstrate that onnamide A suppresses SARS-CoV-2 infection, which may be partially related to entry inhibition, and is expected to be a candidate lead compound for the development of anti-SARS-CoV-2 drugs.

Denigrins H-L: Sulfated Derivatives of Denigrins D and E from a New Zealand Dictyodendrilla c.f. dendyi Marine Sponge.

Five new sulfated arylpyrrole and arylpyrrolone alkaloids, denigrins H-L (1-5), along with two known compounds, dictyodendrin B and denigrin G, were isolated from an extract of a New Zealand Dictyodendrilla c.f. dendyi marine sponge. Denigrins H-L represent the first examples of sulfated denigrins, with denigrins H and I (1-2), as derivatives of denigrin D, containing a pyrrolone core, and denigrins J-L (3-5), as derivatives of denigrin E (6), containing a pyrrole core. Their structures were elucidated by interpretation of 1D and 2D NMR spectroscopic data, ESI, and HR-ESI-MS spectrometric data, as well as comparison with literature data. Compounds 1-5, along with six known compounds previously isolated from the same extract, showed minimal cytotoxicity against the HeLa cervical cancer cell line.

Nested structure role in the mechanical response of spicule inspired fibers

Euplectella aspergillum marine sponge spicules are renowned for their remarkable strength and toughness. These spicules exhibit a unique concentric layering structure, which contributes to their exceptional mechanical resistance. In this study, finite element method simulations were used to comprehensively investigate the effect of nested cylindrical structures on the mechanical properties of spicules. This investigation leveraged scanning electron microscopy images to guide the computational modeling of the microstructure and the results were validated by three-point bending tests of 3D-printed spicule-inspired structures. The numerical analyses showed that the nested structure of spicules induces stress and strain jumps on the layer interfaces, reducing the load on critical zones of the fiber and increasing its toughness. It was found that this effect shows a tapering enhancement as the number of layers increases, which combines with a threshold related to the 3D-printing manufacturability to suggest a compromise for optimal performance. A comprehensive evaluation of the mechanical properties of these fibers can assist in developing a new generation of bioinspired structures with practical real-world applications.

First report of freshwater sponges (Porifera: Demospongiae: Spongillida: Spongillidae) in western Pennsylvania (Ohio River Watershed)

First report of freshwater sponges (Porifera: Demospongiae: Spongillida: Spongillidae) in western Pennsylvania (Ohio River Watershed)

Study on Oil–Water Separation Performance of PDA/ODA Composite–Modified Sponge

ABSTRACTThe study involved the modification of a melamine sponge (SP) through the introduction of polydopamine (PDA) and octadecylamine (ODA), resulting in the creation of three distinct sponge types: PDA/ODA@SP, PDA@SP and ODA@SP. The successful modification of PDA and ODA onto the surface of the sponge was confirmed through the utilisation of scanning electron microscopy and x‐ray photoelectron spectroscopy. Consequently, the resulting sponges exhibited a unique micro–nano composite structure. Wettability testing was conducted to assess the properties of the sponges, revealing that the PDA/ODA@SP sponge demonstrated hydrophobic superlipophilic characteristics. Moreover, a series of 10 repeated oil–water separation experiments indicated that the PDA/ODA@SP sponge achieved an impressive separation efficiency of up to 97%, demonstrating its exceptional oil–water separation capabilities and reusability. Additionally, investigations utilising soybean oil and engine oil demonstrated the composite sponge's superior absorption capabilities for fatty acids and hydrocarbons.