Marine heatwave-driven mass mortality and microbial community reorganisation in an ecologically important temperate sponge.

Marine heatwaves (MHWs) are increasing in frequency, duration and intensity, disrupting global marine ecosystems. While most reported impacts have been in tropical areas, New Zealand experienced its strongest and longest MHW in 2022, profoundly affecting marine sponges. Sponges are vital to rocky benthic marine communities, with their abundance influencing ecosystem functioning. This study examines the impact of this MHW on the photosynthetic sponge Cymbastella lamellata in Fiordland, New Zealand. We describe the extent, physiological responses, mortality, microbial community changes and ecological impact of this MHW on C. lamellata. The Fiordland MHW reached a maximum temperature of 4.4°C above average, lasting for 259 days. Bleaching occurred in >90% of the C. lamellata Fiordland population. The population size exceeded 66 million from 5 to 25 m, making this the largest bleaching event of its kind ever recorded. We identified the photosynthetic symbiont as a diatom, and bleached sponges had reduced photosynthetic efficiency. Post-MHW surveys in 2023 found that over 50% of sponges at sampling sites had died but that the remaining sponges had mostly recovered from earlier bleaching. Using a simulated MHW experiment, we found that temperature stress was a driver of necrosis rather than bleaching, despite necrosis only rarely being observed in the field (<2% of sponges). This suggests that bleaching may not be the cause of the mortality directly. We also identified a microbial community shift in surviving sponges, which we propose represents a microbial-mediated adaptive response to MHWs. We also found that C. lamellata are key contributors of dissolved organic carbon to the water column, with their loss likely impacting ecosystem function. We demonstrate the potential for MHWs to disrupt key marine phyla in temperate regions, highlighting how susceptible temperate sponges globally might be to MHWs.

Genome and Compound Analysis of Sioxanthin-Producing Marine Actinobacterium Micromonospora sp. nov. Strain SH-82 Isolated from Sponge Scopalina hapalia.

Pigments and other secondary metabolites originating from marine microbes have been a promising natural colorants and drugs for multifaceted applications. However, marine actinobacteria producing such natural molecules are least investigated in terms of their taxonomy, chemical diversity and applications in biomedical, textile, and food industries. In this study, sioxanthin pigment-producing Gram-positive actinobacteria, Micromonospora sp. strain SH-82 was isolated from a marine sponge, Scopalina hapalia, and its whole genome was analyzed. Strain SH-82is a prolific producer of diverse chemical molecules as it produced more compounds on A1 medium with different culture conditions. The genome size of SH-82 is 6.24 Mb (6,246,890 bp) carrying 23 identified biosynthetic gene clusters. A total of 5415 CDS, 60 tRNA, 9 rRNA, and 1 tmRNA are identified from SH-82 genome. The GC content (%) of whole genome was 71.6%. Strain SH-82 harbors genes encoding type I, type II, and type III polyketide synthases. Based on the multi-locus sequence analysis and fatty acid methyl ester (FAME) composition, strain SH-82 is confirmed as a novel species. The genetic information of Micromonospora sp. SH-82 has been deposited to NCBI under the BioProject ID PRJNA1087320, with corresponding identifiers in the Sequence Read Archive (SRA) as SAMN40439676 and the Genome accession as CP148049.

Outer membrane vesicles from commensal microbes contribute to the sponge Tedania sp. development by regulating the expression level of apoptosis-inducing factor (AIF).

The transition from the swimming larval stage to the settlement stage represents a significant node in the marine sponge developmental process. Previous research has shown that the outer membrane vesicles (OMVs) from the bacterial species Tenacibaculum mesophilum associated with the sponge Tedania sp. influence larval settlement: low concentrations of OMVs increase the attachment rate, whereas high concentrations decrease the attachment rate. Here, by comparing the transcriptomes of sponge larvae in filtered seawater (FSW group) and in FSW supplemented with OMVs (FSW-OMV group), the results indicated that bacterial OMVs affected larval settlement by modulating the expression levels of apoptosis-inducing factor (AIF) in the host. Subsequently, quantitative real-time PCR revealed a decrease in aif expression near the time of settlement (SE) compared to that in the control group. RNA interference (RNAi) was used to target the aif gene, and the rate of larval settlement was significantly reduced, confirming the inhibitory effect of high concentrations of OMVs. Moreover, small RNA (sRNA) sequencing of OMVs revealed the existence of abundant AIF-sRNAs of 30 nt, further suggesting that one pathway for the involvement of sponge-associated bacteria in host development is the transport of OMVs and the direct function of cargo loading.

Transcriptomic responses of Mediterranean sponges upon encounter with symbiont microbial consortia.

BACKGROUND: Sponges (phylum Porifera) constantly interact with microbes. They graze on microbes from the water column by filter-feeding and they harbor symbiotic partners within their bodies. In experimental setups, sponges take up symbionts at lower rates compared with seawater microbes. This suggests that sponges have the capacity to differentiate between microbes and preferentially graze in non-symbiotic microbes, although the underlying mechanisms of discrimination are still poorly understood. Genomic studies showed that, compared to other animal groups, sponges present an extended repertoire of immune receptors, in particular NLRs, SRCRs, and GPCRs, and a handful of experiments showed that sponges regulate the expression of these receptors upon encounter with microbial elicitors. We hypothesize that sponges may rely on differential expression of their diverse repertoire of poriferan immune receptors to sense different microbial consortia while filter-feeding. To test this, we characterized the transcriptomic response of two sponge species, Aplysina aerophoba and Dysidea avara, upon incubation with microbial consortia extracted from A. aerophoba in comparison with incubation with seawater microbes. The sponges were sampled after 1 h, 3 h, and 5 h for RNA-Seq differential gene expression analysis. RESULTS: D. avara incubated with A. aerophoba-symbionts regulated the expression of genes related to immunity, ubiquitination, and signaling. Within the set of differentially-expressed immune genes we identified different families of Nucleotide Oligomerization Domain (NOD)-Like Receptors (NLRs). These results represent the first experimental evidence that different types of NLRs are involved in microbial discrimination in a sponge. In contrast, the transcriptomic response of A. aerophoba to its own symbionts involved comparatively fewer genes and lacked genes encoding for immune receptors. CONCLUSION: Our work suggests that: (i) the transcriptomic response of sponges upon microbial exposure may imply "fine-tuning" of baseline gene expression as a result of their interaction with microbes, (ii) the differential response of sponges to microbial encounters varied between the species, probably due to species-specific characteristics or related to host's traits, and (iii) immune receptors belonging to different families of NLR-like genes played a role in the differential response to microbes, whether symbionts or food bacteria. The regulation of these receptors in sponges provides further evidence of the potential role of NLRs in invertebrate host-microbe interactions. The study of sponge responses to microbes exemplifies how investigating different animal groups broadens our knowledge of the evolution of immune specificity and symbiosis.

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.

Streptomyces-Fungus Co-Culture Enhances the Production of Borrelidin and Analogs: A Genomic and Metabolomic Approach.

The marine Streptomyces harbor numerous biosynthetic gene clusters (BGCs) with exploitable potential. However, many secondary metabolites cannot be produced under laboratory conditions. Co-culture strategies of marine microorganisms have yielded novel natural products with diverse biological activities. In this study, we explored the metabolic profiles of co-cultures involving Streptomyces sp. 2-85 and Cladosporium sp. 3-22-derived from marine sponges. Combining Global Natural Products Social (GNPS) Molecular Networking analysis with natural product database mining, 35 potential antimicrobial metabolites annotated were detected, 19 of which were exclusive to the co-culture, with a significant increase in production. Notably, the Streptomyces-Fungus interaction led to the increased production of borrelidin and the discovery of several analogs via molecular networking. In this study, borrelidin was first applied to combat Saprolegnia parasitica, which caused saprolegniosis in aquaculture. We noted its superior inhibitory effects on mycelial growth with an EC50 of 0.004 mg/mL and on spore germination with an EC50 of 0.005 mg/mL compared to the commercial fungicide, preliminarily identifying threonyl-tRNA synthetase as its target. Further analysis of the associated gene clusters revealed an incomplete synthesis pathway with missing malonyl-CoA units for condensation within this strain, hinting at the presence of potential compensatory pathways. In conclusion, our findings shed light on the metabolic changes of marine Streptomyces and fungi in co-culture, propose the potential of borrelidin in the control of aquatic diseases, and present new prospects for antifungal applications.

Potential of Polar Lipids Isolated from the Marine Sponge Haliclona (Halichoclona) vansoesti against Melanoma.

Marine sponges represent a good source of natural metabolites for biotechnological applications in the pharmacological, cosmeceutical, and nutraceutical fields. In the present work, we analyzed the biotechnological potential of the alien species Haliclona (Halichoclona) vansoesti de Weerdt, de Kluijver & Gomez, 1999, previously collected in the Mediterranean Sea (Faro Lake, Sicily). The bioactivity and chemical content of this species has never been investigated, and information in the literature on its Caribbean counterpart is scarce. We show that an enriched extract of H. vansoesti induced cell death in human melanoma cells with an IC50 value of 36.36 µg mL-1, by (i) triggering a pro-inflammatory response, (ii) activating extrinsic apoptosis mediated by tumor necrosis factor receptors triggering the mitochondrial apoptosis via the involvement of Bcl-2 proteins and caspase 9, and (iii) inducing a significant reduction in several proteins promoting human angiogenesis. Through orthogonal SPE fractionations, we identified two active sphingoid-based lipid classes, also characterized by nuclear magnetic resonance and mass spectrometry, as the main components of two active fractions. Overall, our findings provide the first evaluation of the anti-cancer potential of polar lipids isolated from the marine sponge H. (Halichoclona) vansoesti, which may lead to new lead compounds with biotechnological applications in the pharmaceutical field.

Ammonium nitrogen and phosphorus removal by bacterial-algal symbiotic dynamic sponge bioremediation system in micropolluted water: Operational mechanism and transformation pathways.

Construct a bacteria-algae symbiotic dynamic sponge bioremediation system to simultaneously remove multiple pollutants under micro-pollution conditions. The average removal efficiencies of NH4+-N, PO43--P, total nitrogen (TN), and Ca2+ were 98.35, 78.74, 95.64, and 84.92 %, respectively. Comparative studies with Auxenochlorella sp. sponge and bacterial sponge bioremediation system confirmed that NH4+-N and TN were mainly removed by bacterial heterotrophic nitrification - aerobic denitrification (HN-AD). PO43--P was removed by algal assimilation and the generation of Ca3(PO4)2 and Ca5(PO4)3OH, and Ca2+ was removed by algal electron transfer formation of precipitates and microbially induced calcium precipitation (MICP) by bacteria. Algae provided an aerobic environment for the bacterial HN-AD process through photosynthesis, while respiration produced CO2 and adsorbed Ca2+ to promote the formation of calcium precipitates. Immobilization of Ca2+ with microalgae via bacterial MICP helped to lift microalgal photoinhibition. The bioremediation system provides theoretical support for research on micropolluted water treatment while increasing phosphorus recovery pathways.

The marine-derived HIF-1α inhibitor, Yardenone 2, reduces prostate cancer cell proliferation by targeting HIF-1 target genes.

BACKGROUND: Prostate cancer (PCa) ranks as the second most prevalent cancer in men, with advanced stages posing significant treatment challenges. Given its solid tumor nature, PCa is highly susceptible to hypoxia, a condition associated with resistance to radiation and chemotherapy, metastasis, and unfavorable patient outcomes. Hypoxia-inducible factors (HIFs) play a pivotal role in cancer cell adaptation to hypoxic environments, contributing to treatment resistance. Consequently, inhibitors targeting HIFs hold promise for cancer therapy. METHODS: In this study, we aimed to characterize novel HIF-1α inhibitors including Sodwanones A (1), B (2), C (3), G (4) and Yardenone 2 (5) isolated from marine sponges belonging to the Axinella genus. Our investigation evaluated the impact of these compounds on various aspects of HIF-1α regulation, including stabilization, nuclear localization, expression of HIF-1 target genes (while sparing HIF-2 target genes), cellular metabolism, as well as cell proliferation and viability in prostate cells under hypoxic conditions. RESULTS: Our findings revealed that among the compounds tested, Yardenone 2 exhibited notable effects in hypoxia: it destabilized HIF-1α at the protein level, decreased its nuclear localization, selectively altered the expression of HIF-1 target genes, and restrained cell proliferation in aggressive PC3 prostate cancer cells as well as in an MSK-PCa3 patient-derived organoid line. Moreover, it affected the morphology of these organoid. Yardenone 2 was also compared to Docetaxel, a specific microtubule inhibitor and a drug used in the treatment of prostate cancer. The comparison between the two compounds revealed notable differences, such as a lack of specificity to hypoxic cells of Docetaxel. CONCLUSION: These results mark the first demonstration that Yardenone 2 functions as a cytostatic-like inhibitor impacting microtubules, specifically targeting hypoxic cancer cells. This discovery suggests a promising avenue for novel therapeutic interventions in prostate cancer.

Out of the blue: Hyperaccumulation of molybdenum in the Indo-Pacific sponge Theonella conica.

Molybdenum is an essential micronutrient, but because of its toxicity at high concentrations, its accumulation in living organisms has not been widely demonstrated. In this study, we report that the marine sponge Theonella conica accumulates exceptionally high levels of molybdenum (46,793 micrograms per gram of dry weight) in a wide geographic distribution from the northern Red Sea to the reefs of Zanzibar, Indian Ocean. The element is found in various sponge body fractions and correlates to selenium. We further investigated the microbial composition of the sponge and compared it to its more studied congener, Theonella swinhoei. Our analysis illuminates the symbiotic bacterium Entotheonella sp. and its role in molybdenum accumulation. Through microscopic and analytical methods, we provide evidence of intracellular spheres within Entotheonella sp. that exhibit high molybdenum content, further unraveling the intricate mechanisms behind molybdenum accumulation in this sponge species and its significance in the broader context of molybdenum biogeochemical cycling.

Diversity and structure of the deep-sea sponge microbiome in the equatorial Atlantic Ocean.

Sponges (phylum Porifera) harbour specific microbial communities that drive the ecology and evolution of the host. Understanding the structure and dynamics of these communities is emerging as a primary focus in marine microbial ecology research. Much of the work to date has focused on sponges from warm and shallow coastal waters, while sponges from the deep ocean remain less well studied. Here, we present a metataxonomic analysis of the microbial consortia associated with 23 individual deep-sea sponges. We identify a high abundance of archaea relative to bacteria across these communities, with certain sponge microbiomes comprising more than 90 % archaea. Specifically, the archaeal family Nitrosopumilaceae is prolific, comprising over 99 % of all archaeal reads. Our analysis revealed that sponge microbial communities reflect the host sponge phylogeny, indicating a key role for host taxonomy in defining microbiome composition. Our work confirms the contribution of both evolutionary and environmental processes to the composition of microbial communities in deep-sea sponges.

Structure Determination of 1,3-Dioxolane-Containing Lipids from the Marine Sponge Leucetta sp. Using Chiral 1H NMR Analysis of Model Systems.

Chemical investigation of n-hexane extract from the marine sponge Leucetta sp. led to the isolation of five new lipids, 1-5, each characterized by a substituted dioxolane core. The structures of 1-5 were established based on the interpretation of NMR and HRESIMS data. To assign the absolute configuration at C-1', model systems consisting of diastereomers at C-2, C-4, and C-1' of the dioxolane core were prepared from a chiral glycerol dimethylacetal. 1H NMR inspection of model compounds revealed that a pair of C-1' epimers, 11a/c and 11b/d, was indistinguishable, restricting structural assignment by direct comparison of NMR data. In addition, the lack of chromophores in the dioxolane core resulted in unreliable ECD results, with Cotton effects appearing below 190 nm. As an alternative, a chiral NMR method using Eu(hfc)3 revealed notable lanthanide-induced shifts, allowing the spectroscopic discrimination of 11a/c and ent-11a/c. Therefore, the absolute configuration of all five new lipids was determined to be 2S, 4S, 1'S by direct comparison with the Eu(hfc)3-induced 1H NMR data.

ROS Induced by Aphrocallistes vastus Lectin Enhance Oncolytic Vaccinia Virus Replication and Induce Apoptosis in Hepatocellular Carcinoma Cells.

Oncolytic virotherapy is expected to provide a new treatment strategy for cancer. Aphrocallistes vastus lectin (AVL) is a Ca2+-dependent lectin receptor containing the conserved domain of C-type lectin and the hydrophobic N-terminal region, which can bind to the bird's nest glycoprotein and D-galactose. Our previous studies suggested that the oncolytic vaccinia virus (oncoVV) armed with the AVL gene exerted remarkable replication and antitumor effects in vitro and in vivo. In this study, we found that oncoVV-AVL may reprogram the metabolism of hepatocellular carcinoma cells to promote ROS, and elevated ROS subsequently promoted viral replication and induced apoptosis. This study will provide a new theoretical basis for the application of oncoVV-AVL in liver cancer.

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.

Exploring the secrets of marine microorganisms: Unveiling secondary metabolites through metagenomics.

Marine microorganisms are increasingly recognized as primary producers of marine secondary metabolites, drawing growing research interest. Many of these organisms are unculturable, posing challenges for study. Metagenomic techniques enable research on these unculturable microorganisms, identifying various biosynthetic gene clusters (BGCs) related to marine microbial secondary metabolites, thereby unveiling their secrets. This review comprehensively analyses metagenomic methods used in discovering marine microbial secondary metabolites, highlighting tools commonly employed in BGC identification, and discussing the potential and challenges in this field. It emphasizes the key role of metagenomics in unveiling secondary metabolites, particularly in marine sponges and tunicates. The review also explores current limitations in studying these metabolites through metagenomics, noting how long-read sequencing technologies and the evolution of computational biology tools offer more possibilities for BGC discovery. Furthermore, the development of synthetic biology allows experimental validation of computationally identified BGCs, showcasing the vast potential of metagenomics in mining marine microbial secondary metabolites.

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.

Adapting to the Abyss: Passive Ventilation in the Deep-Sea Glass Sponge Euplectella aspergillum.

We analyze the flow physics inside the body cavity and downstream the deep-sea glass sponge Euplectella aspergillum. We provide evidence that the helical skeletal motifs of the sponge give rise to a rich fluid dynamic field, allowing the organism to scavenge flow from the bottom of the sea and promoting a spontaneous, organized vertical flow within its body cavity toward the osculum. Our analysis points at a functional adaptation of the organism, which can passively divert flow through the osculum in unfavorable, low ambient currents, with no need for active pumping, with potential repercussions in functional ecology, as well as the design of chemical reactors, air-treatment units, and civil and aeronaval structures.

A late-Ediacaran crown-group sponge animal.

Sponges are the most basal metazoan phylum1 and may have played important roles in modulating the redox architecture of Neoproterozoic oceans2. Although molecular clocks predict that sponges diverged in the Neoproterozoic era3,4, their fossils have not been unequivocally demonstrated before the Cambrian period5-8, possibly because Precambrian sponges were aspiculate and non-biomineralized9. Here we describe a late-Ediacaran fossil, Helicolocellus cantori gen. et sp. nov., from the Dengying Formation (around 551-539 million years ago) of South China. This fossil is reconstructed as a large, stemmed benthic organism with a goblet-shaped body more than 0.4 m in height, with a body wall consisting of at least three orders of nested grids defined by quadrate fields, resembling a Cantor dust fractal pattern. The resulting lattice is interpreted as an organic skeleton comprising orthogonally arranged cruciform elements, architecturally similar to some hexactinellid sponges, although the latter are built with biomineralized spicules. A Bayesian phylogenetic analysis resolves H. cantori as a crown-group sponge related to the Hexactinellida. H. cantori confirms that sponges diverged and existed in the Precambrian as non-biomineralizing animals with an organic skeleton. Considering that siliceous biomineralization may have evolved independently among sponge classes10-13, we question the validity of biomineralized spicules as a necessary criterion for the identification of Precambrian sponge fossils.

Bionic design of thin-walled bilinear tubes with excellent crashworthiness inspired by glass sponge structures.

In order to enhance energy absorption, this study draws inspiration from the diagonal bilinear robust square lattice structure found in deep-sea glass sponges, proposing a design for thin-walled structures with superior folding capabilities and high strength-to-weight ratio. Firstly, the crashworthiness of bionic glass sponge tube (BGSTO) is compared with that of equal-wall-thickness equal-mass four-X tube through both experiments and simulations, and it is obtained that the specific energy absorption of BGSTO is increased by 78.64%. And the crashworthiness of BGSTO is also most significant compared to that of multicellular tubes with the similar number of crystalline cells. Additionally, we found that the double-line spacing of the glass sponge can be freely adjusted without changing the material amount. Therefore, based on BGSTO, we designed two other double-line structures, BGSTA and BGSTB. Then with equal wall thickness and mass as a prerequisite, this study proceeds to design and compare the energy absorption properties of three bilinear thin-walled tubes in both axial and lateral cases. The deformation modes and crashworthiness of the three types of tubes with variable bilinear spacing (ßO/A/B) are comparatively analysed. The improved complex proportional assessment (COPRAS) synthesis decision is used to obtain that BGSTO exhibits superior crashworthiness over the remaining two kinds of tubes. Finally, a surrogate model is established to perform multi-objective optimization on the optimal bilinear configuration BGSTO selected by the COPRAS method.

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.