The pillars of the sea: strategies to achieve successful marine citizen science programs in the Mediterranean area.

Marine ecosystems are facing a dramatic loss of biodiversity worldwide, together with a widespread collapse of habitats and their functionality. In this context, Marine Citizen Science (MCS) can be a powerful tool to monitor these changes over time. The flowering of very well-structured international projects is strengthening the scientific credibility of MCS data, especially when data are collected after specifically designed training programs and shared in public user-friendly repositories. Here we present a new perspective on the use of MCS in the Mediterranean area, along with the main benefits for the stakeholders (i.e., diving centers, trainers, and policymakers) and the users (i.e., divers), resumed in three pillars: Pillar I - MCS as a tool for the site valorization; Pillar II - MCS as a new career opportunity for graduated students; Pillar III - MCS as a business opportunity for diving centers. In the frame of the Quintuple Helix Approach, for which there is a strong need of a socioecological transition of the society and economy, we show how MCS can be a win-win-win solution for all the actors involved, providing the vision for new and highly qualified job and business opportunities for the diving sector.

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.

Wajeepeptin, a Cytotoxic and Antitrypanosomal Cyclic Depsipeptide from a Marine Moorena sp. Cyanobacterium.

Here, we report wajeepeptin (1), a new cyclic depsipeptide isolated from a marine Moorena sp. cyanobacterium. The structure was elucidated by a combination of spectroscopic analyses, X-ray diffraction analysis, and degradation reactions. Wajeepeptin (1) showed moderate cytotoxicity (IC50 = 3.7 µM against HeLa cells) and potent antitrypanosomal activity (IC50 = 0.73 ± 0.14 µM against Trypanosoma brucei rhodesiense).

Bromine/Sulfur-Substituted 9H-Carbazoles Produced by the Marine-Derived Streptomyces sp. OUCMDZ-5511 upon NaBr Exposure.

Ten undocumented carbazole derivatives (2-11) along with the reported analogue (1) were isolated from the mangrove-derived Streptomyces sp. OUCMDZ-5511, cultured with NaBr-supplemented liquid medium. Compounds 1-7 are brominated carbazoles, and 8, 10, and 11 feature an additional thiazole or 2,3-dihydro-1,4-oxathiine rings, respectively. Their structures were identified through spectroscopic techniques, computational chemistry, and X-ray crystallography. Notably, compounds 6 and 8 effectively inhibited immune cell migration, indicating anti-inflammatory activity in vivo, potentially via Myd88/Nf-κB pathways, as suggested for compound 6.

Discovery of the Lipopeptides Albubactins A-H from Streptomyces albidoflavus RKJM0023 via Chemical Elicitation with Rhamnolipids and Synthesis of Albubactin A.

The marine tunicate-derived Streptomyces albidoflavus RKJM0023 was cultured in the presence of a rhamnolipid mixture in an effort to elicit the production of silent natural products. MS/MS-based molecular networking analysis enhanced with nonparametric statistics highlighted the upregulation of a molecular cluster (Kruskal-Wallis p = 1.6 e-6 for 1) in which no MS/MS features had library matches. Targeted isolation of these features resulted in the discovery of nine new N-acylated lipopeptides, albubactins A-H (1-8) each containing a unique glutamine tripeptide and a C-terminal ethyl ester moiety. Three related albubactin acids A-C (9-11) lacking the ethyl ester were also identified. NMR spectroscopy and UPLC-HR-ESI-MS/MS demonstrated that the albubactins were obtained as mixtures that shared a common m/z and differed only in their acylated terminal groups. Due to the complex spectroscopic elucidation with many overlapping shifts, a total synthesis of albubactin A (1) was completed and used to determine the absolute configuration of the new albubactins.

Discovery of Oxidized p-Terphenyls as Phosphodiesterase 4 Inhibitors from Marine-Derived Fungi.

Four new p-terphenyl derivatives, talaroterphenyls A-D (1-4), together with three biosynthetically related known ones (5-7), were obtained from the mangrove sediment-derived Talaromyces sp. SCSIO 41412. Compounds 1-3 are rare p-terphenyls, which are completely substituted on the central benzene ring by oxygen atoms; this is the first report of their isolation from natural sources. Their structures were elucidated through NMR spectroscopy, HRESIMS, and X-ray diffraction. Genome sequence analysis revealed that 1-7 were biosynthesized from tyrosine and phenylalanine, involving four key biosynthetic genes (ttpB-ttpE). These p-terphenyls (1-7) and 36 marine-derived terphenyl analogues (8-43) were screened for phosphodiesterase 4 (PDE4) inhibitory activities, and 1-5, 14, 17, 23, and 26 showed notable activities with IC50 values of 0.40-16 µM. The binding pattern of p-terphenyl inhibitors 1-3 with PDE4 were explored by molecular docking analysis. Talaroterphenyl A (1), with a low cytotoxicity, showed obvious anti-inflammatory activity in LPS-stimulated RAW264.7 cells. Furthermore, in the TGF-ß1-induced medical research council cell strain-5 (MRC-5) pulmonary fibrosis model, 1 could down-regulate the expression levels of FN1, COL1, and α-SMA significantly at concentrations of 5-20 µM. This study suggests that the oxidized p-terphenyl 1, as a marine-derived PDE4 inhibitor, could be used as a promising antifibrotic agent.

The Kavaratamides: Discovery of Linear Lipodepsipeptides from the Marine Cyanobacterium Moorena bouillonii Using a Comparative Chemogeographic Analysis.

Kavaratamide A (1), a new linear lipodepsipeptide possessing an unusual isopropyl-O-methylpyrrolinone moiety, was discovered from the tropical marine filamentous cyanobacterium Moorena bouillonii collected from Kavaratti, India. A comparative chemogeographic analysis of M. bouillonii collected from six different geographical regions led to the prioritized isolation of this metabolite from India as distinctive among our data sets. AI-based structure annotation tools, including SMART 2.1 and DeepSAT, accelerated the structure elucidation by providing useful structural clues, and the full planar structure was elucidated based on comprehensive HRMS, MS/MS fragmentation, and NMR data interpretation. Subsequently, the absolute configuration of 1 was determined using advanced Marfey's analysis, modified Mosher's ester derivatization, and chiral-phase HPLC. The structures of kavaratamides B (2) and C (3) are proposed based on a detailed analysis of their MS/MS fragmentations. The biological activity of kavaratamide A was also investigated and found to show moderate cytotoxicity to the D283-medullablastoma cell line.

Total Syntheses of the Structures Assigned to Denigrins A, B, C, F, and G, 3,4-Diaryl-Pyrrole and -Pyrrolidinone Alkaloids, and the Conversion of Congener B into the Co-metabolite Spirodactylone.

The title marine natural products have been prepared by total synthesis and in the case of congeners 3, 6, and 7 for the first time. Each of these was obtained by manipulation of readily prepared denigrin B (2). The structure, 3, assigned to denigrin C is shown to be incorrect. Reaction of compound 2 with DDQ has led, in high yield, to the related natural product spirodactylone (16), while treating the corresponding permethyl ether 15 with PIFA/BF3·Et2O provides compound 20, embodying an isomeric framework.

Total Synthesis and Antibacterial Activity of Marine Tris-indole Alkaloid Tulongicin A.

Bis-indole alkaloids from marine sponges are an intriguing class of natural products with a variety of activities. However, only a preliminary biological study of tulongicin A (5), a related previously isolated marine tris-indole alkaloid, has been conducted. In this study, we accomplished the first asymmetric total synthesis of 5 via the construction of an imidazoline-linked bis-indolylmethane skeleton using a Friedel-Crafts-type reaction. Our synthesis enabled a detailed study of the antibacterial profile of 5. Compound 5 displayed bactericidal activity against Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) strains.

Discovery of Biofilm Inhibitors from the Microbiota of Marine Egg Masses.

Biofilms commonly develop in immunocompromised patients, which leads to persistent infections that are difficult to treat. In the biofilm state, bacteria are protected against both antibiotics and the host's immune system; currently, there are no therapeutics that target biofilms. In this study, we screened a chemical fraction library representing the natural product capacity of the microbiota of marine egg masses, namely, the moon snail egg collars. This led to the identification of active fractions targeting both Pseudomonas aeruginosa and Staphylococcus aureus biofilms. Subsequent analysis revealed that a subset of these fractions were capable of eradicating preformed biofilms, all against S. aureus. Bioassay-guided isolation led us to identify pseudochelin A, a known siderophore, as a S. aureus biofilm inhibitor with an IC50 of 88.5 µM. Mass spectrometry-based metabolomic analyses revealed widespread production of pseudochelin A among fractions possessing S. aureus antibiofilm properties. In addition, a key biosynthetic gene involved in producing pseudochelin A was detected on 30% of the moon snail egg collars and pseudochelin A is capable of inhibiting the formation of biofilms (IC50 50.6 µM) produced by ecologically relevant bacterial strains. We propose that pseudochelin A may have a role in shaping the microbiome or protecting the egg collars from microbiofouling.

The tiny giant of the sea, Ostreococcus's unique adaptations.

Ostreococcus spp. are unicellular organisms with one of the simplest cellular organizations. The sequencing of the genomes of different Ostreococcus species has reinforced this status since Ostreococcus tauri has one most compact nuclear genomes among eukaryotic organisms. Despite this, it has retained a number of genes, setting it apart from other organisms with similar small genomes. Ostreococcus spp. feature a substantial number of selenocysteine-containing proteins, which, due to their higher catalytic activity compared to their selenium-lacking counterparts, may require a reduced quantity of proteins. Notably, O. tauri encodes several ammonium transporter genes, that may provide it with a competitive edge for acquiring nitrogen (N). This characteristic makes it an intriguing model for studying the efficient use of N in eukaryotes. Under conditions of low N availability, O. tauri utilizes N from abundant proteins or amino acids, such as L-arginine, similar to higher plants. However, the presence of a nitric oxide synthase (L-arg substrate) sheds light on a new metabolic pathway for L-arg in algae. The metabolic adaptations of O. tauri to day and night cycles offer valuable insights into carbon and iron metabolic configuration. O. tauri has evolved novel strategies to optimize iron uptake, lacking the classic components of the iron absorption mechanism. Overall, the cellular and genetic characteristics of Ostreococcus contribute to its evolutionary success, making it an excellent model for studying the physiological and genetic aspects of how green algae have adapted to the marine environment. Furthermore, given its potential for lipid accumulation and its marine habitat, it may represent a promising avenue for third-generation biofuels.

Talaromides A-C, Bioactive Cyclic Heptapeptides from Talaromyces siglerae Isolated from a Marine Sponge.

Three new cyclic heptapeptides, talaromides A-C (1-3), were isolated from cultures produced by the fungus Talaromyces siglerae (Ascomycota), isolated from an unidentified sponge. The structures, featuring an unusual proline-anthranilic moiety, were elucidated by analysis of spectroscopic data and chemical transformations, including the advanced Marfey's method and GITC derivatization. Talaromides A and B inhibited migration activity against PANC-1 human pancreatic cancer cells without significant cytotoxicity.

Terpenoids from the Soft Coral Stereonephthya bellissima.

A detailed chemical study of the extract from the soft coral Stereonephthya bellissima resulted in the isolation and identification of seven new sesquiterpenoids, bellissinanes A-G (1-7), along with four new diterpenes (8-11). Bellissinane A (1) is the third reported nardosinane-type sesquiterpene bearing a 6/5/6 tricyclic system. Bellissinanes C and D (3, 4) contain a phenylethylamine fragment, which is relatively unusual in marine organisms. Bellissinanes E-G (5-7) belong to the rare class of nornardosinane sesquiterpenoids. Structurally uncommon octahydro-1H-indenyl-type and prenyleudesmane-type skeletons were characterized for herpetopanone B (8) and bellissimain A (9), respectively. Bellissinane E (5) exhibited in vivo angiogenesis-promoting activity.

Microascones, Decahydrofluorene-Class Alkaloids from the Marine-Derived Fungus Microascus sp. SCSIO 41821.

Eight new decahydrofluorene-class alkaloids, microascones A and B (1 and 2), 2,3-epoxyphomapyrrolidone C (3), 14,16-epiascomylactam B (4), 24-hydroxyphomapyrrolidone A (5), and microascones C-E (6-8), along with five known analogs (9-13) were isolated from the marine-derived fungus Microascus sp. SCSIO 41821. Compounds 1 and 2 have an unprecedented complex macrocyclic alkaloid skeleton with a 6/5/6/5/6/5/13 polycyclic system. Their structures and absolute configurations were determined by spectroscopic analysis, quantum chemical calculations of ECD spectra, and 13C NMR chemical shifts. Compounds 10-13 showed selective enzyme inhibitory activity against PTPSig, PTP1B, and CDC25B, and 4, 9, and 10 exhibited strong antibacterial activity against seven tested pathogens. Their structure-bioactivity relationship was discussed, and a plausible biosynthetic pathway for 1-8 was also proposed.

Neopetromin, a Cyclic Tripeptide with a C-N Cross-Link, from the Marine Sponge Neopetrosia sp., That Causes Vacuole Fragmentation in Tobacco BY-2 Cells.

HPLC-MS analysis revealed the presence of an unreported peptide in the extract of the marine sponge Neopetrosia sp. Its structure was determined as a tripeptide, named neopetromin (1), composed of two tyrosine and one tryptophan residues with a heteroaromatic C-N cross-link between side chains. The absolute configuration of amino acids was determined using Marfey's method after ozonolysis and hydrolysis of 1. Compound 1 promoted vacuole fragmentation in an actin-independent manner in tobacco BY-2 cells.

The allocation of carbon resources in marine capture fisheries.

Marine fishery carbon emissions play a significant role in agricultural carbon emissions, making resource allocation a crucial topic for the overall marine ecological protection. This paper evaluates the dynamic iteration method as a research approach with the factors of resource allocation consisting of value assessment, optimization objective, difference between value assessment and objective, and optimization calculation. The paper selects the shadow price from the Super-SBM model as the judgment function for the goal value, aiming for the fairness criterion. From an equity standpoint, the allocation of carbon resources in marine capture fisheries proves to be unreasonable. The fishery model exhibits an excessive supply of carbon resources, resulting in wastage, while the green fishery model faces a relatively limited supply, with a focus on energy conservation and environmental protection. To address this issue, this paper proposes a new method and discusses the corrective results. This result shows that the stabilization point achieved is a short-term equilibrium rather than a long-term one. By rectifying the social contradiction of profit-oriented approaches, this research provides a fresh perspective for economic studies and applications, particularly in industrial layout and resource utilization optimization.

A MassQL-Integrated Molecular Networking Approach for the Discovery and Substructure Annotation of Bioactive Cyclic Peptides.

The marine sponge-derived fungus Stachylidium bicolor 293 K04 is a prolific producer of specialized metabolites, including certain cyclic tetrapeptides called endolides, which are characterized by the presence of the unusual amino acid N-methyl-3-(3-furyl)-alanine. This rare feature can be used as bait to detect new endolide-like analogs through customized fragment pattern searches of tandem mass spectrometry data using the Mass Spec Query Language (MassQL). Here, we integrate endolide-specific MassQL queries with molecular networking to obtain substructural information guiding the targeted isolation and structure elucidation of the new proline-containing endolides E (1) and F (2). We showed that endolide F (but not E) is a moderate antagonist of the arginine vasopressin V1A receptor, a member of the G protein-coupled receptor superfamily.

HPPO-Derived Meroterpenoids from the Marine-Derived Fungus Penicillium sp. SCSIO 41691.

Seven new 4-hydroxy-6-phenyl-2H-pyran-2-one (HPPO) derived meroterpenoids, 1-methyl-12a,12b-epoxyarisugacin M (1), 1-methyl-4a,12b-epoxyarisugacin M (2), 2,3-dihydroxy-3,4a-epoxy-12a-dehydroxyisoterreulactone A (3), 2-hydroxy-12a-dehydroxyisoterreulactone A (4), 3'-demethoxyterritrems B' (5), 4a-hydroxyarisugacin P (6), and 1-epi-arisugacin H (7), together with two known analogues (8 and 9), were isolated from the marine-derived fungal strain Penicillium sp. SCSIO 41691. Their structures were elucidated by spectroscopic methods, and the absolute configurations of compounds 1 and 3 were determined by single-crystal X-ray diffraction. Among them, 1 and 2 had a unique methyl migration in the basic meroterpenoid skeleton with a 12a,12b-epoxy or 4a,12b-epoxy group, and 3 was a highly oxygenated HPPO-derived meroterpenoid featuring a rare 6/5/6/6/6/6 hexacyclic system with a 3,4a-epoxy group. Biologically, 5 exhibited inhibitory activity against lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells with an IC50 value of 21 µM, more potent than the positive control indomethacin.