Marine opisthobranch mollusks are a valuable source of structurally diverse bioactive metabolites arising from de novo biosynthesis or dietary origins. Jorumycidine (4) is a novel bis-tetrahydroisoquinoline (bis-THIQ) alkaloid with an unprecedented hexacyclic skeleton, isolated together with jorumycin (2), renieramycin E (3), and new 21-deoxy analogues (5, 6) from the nudibranch Jorunna funebris and its dietary sponge Haliclona sp. The structure of jorumycidine, featuring a unique oxazolidine ring, was elucidated by spectroscopic, spectrometric, and chiroptical analyses. LC-MS/MS diagnostic fragmentation filtering (DFF), combined with re-annotation of the ren biosynthetic gene cluster recently identified in a Haliclona endosymbiont, supported a hybrid NRPS-PKS origin and revealed enzymatic conversion of sponge-derived renieramycins into jorumycins by the nudibranch. Jorumycidine exhibited potent nanomolar cytotoxicity (IC₅₀ = 13.8 nM) against multiple myeloma cells, outperforming its congeners. These findings expand bis-THIQ chemical diversity and demonstrate how interspecies metabolic interplay can generate bioactive scaffolds with therapeutic potential.

Marine mollusks of the order Nudibranchia produce a wide array of secondary metabolites that play key roles in predator-prey interactions and often exhibit remarkable bioactivity. In this study, a chemical investigation of the Mediterranean aeolid nudibranchs Cratena peregrina and Paraflabellina ischitana led to the isolation and characterization of a novel oxylipin, designated cratenin (1). This unique metabolite shows an unusual alkylated monosubstituted tetrahydrofuran (THF) moiety, a structural feature rarely encountered among marine natural products. The planar structure of 1 was fully elucidated by high-resolution mass spectrometry (HRMS) and comprehensive 1D and 2D NMR spectroscopy, while the absolute configuration of the substituted THF ring was rigorously established by chemical degradation, derivatization, and NMR-based stereochemical comparison with known diasteromeric derivatives of (tetrahydrofuran-2-yl)methanol. The co-occurrence of cratenin (1) in the hydrozoan Eudendrium racemosum, a known prey of C. peregrina and other aeolid nudibranchs, strongly suggests its role as a semiochemical which mediates predator-prey interactions. The proposed biosynthetic origin of cratenin (1) from algal docosahexaenoic acid (DHA) further corroborates the hypothesis of dietary acquisition and provides compelling molecular evidence for kleptopredation, a sophisticated foraging behavior where nudibranchs consume prey that has recently ingested phytoplankton. In this view, this study reveals a clear metabolic and ecological link connecting phytoplankton, hydrozoans, and nudibranchs, underscoring the pivotal role of lipid-derived natural products in shaping chemical communication and interphyletic trophic interactions involving opisthobranchs.

Five new rifamycin derivatives, named salinirifamycins A-E (1-5), were isolated from a Brazilian marine Salinispora arenicola (BRA-213) strain extract. The structures of the new rifamycins were elucidated using a combination of NMR, IR, UV, and MS spectroscopic techniques, quantum-chemical calculations (DFT-calculated 13C NMR chemical shifts and DP4+ probability analysis), and comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Compounds 1, 2, and 4 displayed antibacterial activity against Staphylococcus aureus and Enterococcus faecalis with MIC values ranging from 2.0 to 125.0 μg/mL, whereas 5 exhibited an MIC of 0.02 μg/mL to S. aureus, similar to the positive control rifampicin (MIC 0.03 μg/mL).

Polyketides (PKs) are a widespread class of secondary metabolites with recognised pharmacological properties. These molecules are abundantly produced in the marine environment, especially by dinoflagellate-photosynthetic organisms able to produce several PKs, including neurotoxins, cytotoxins, and immunomodulating agents. The biosynthesis of these compounds is driven by a conserved enzymatic process involving polyketide synthase complexes. Different genera of dinoflagellates produce PKs. Among them, dinoflagellates of the genus Amphidinium are of particular interest due to its ability to produce the following two major families of PKs: amphidinolides and amphidinols. These compounds display remarkable biological activities, including anticancer, antimicrobial, and antifungal effects, making them attractive targets for pharmaceutical research and development. However, the natural yield of Amphidinium-derived polyketides (APKs) is generally low, limiting their potential for sustainable molecular farming. This challenge has prompted interest in developing biotechnological strategies to enhance their production. This review aims to define the current state of studies about APKs, starting from their initial discoveries to the recent understanding of their biosynthetic pathways. Additionally, it summarizes the structures of compounds discovered, highlights their biotechnological potential, and discusses novel trends in their production.

Desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) is among the most powerful techniques for visualizing the spatial distribution of small organic molecules, particularly lipids, on tissue surfaces. Conventional DESI-MSI analysis typically involves sectioning fresh-frozen tissues or, less commonly, embedding samples in matrices specifically formulated to preserve the tissue integrity for multifunctional analyses. In this study, we present an optimized sucrose-gelatin hydrogel matrix compatible with DESI-MSI, using mouse brain tissue as a model system. The method involves low-temperature embedding of frozen specimens into the hydrogel matrix, followed by snap-freezing at -160 °C. This matrix formulation ensures minimal background interference and prevents metabolite delocalization, thereby preserving the native molecular composition of the tissue. Notably, sucrose-derived adduct ions restricted to the embedding medium serve as stable internal reference signals in both positive and negative ionization modes. These signals enable continuous lock-mass correction throughout acquisition, offering a new solution to the unresolved challenge for accurate mass-based measurements in DESI-MSI without an infusion of exogenous calibration standards. Complementary DESI-MS/MS analyses further facilitate confident lipid identification and resolve structural ambiguities. Moreover, the sucrose-gelatin embedding medium provides excellent preservation of tissue morphology and antigenicity, supporting subsequent histological and immunohistochemical analyses. Overall, this sucrose-based hydrogel embedding protocol offers a robust, reproducible, and multimodal platform for molecular tissue imaging by DESI-MSI, especially in delicate biological specimens with broad translational potential across preclinical and clinical research domains.

Microglial dysfunction has emerged as a critical factor in the Alzheimer’s Disease (AD), with innate immune dysregulation driving pathological progression. This growing understanding has shifted attention toward the therapeutic modulation of glial response as a means to restore immune balance and promote neuronal resilience. Increasing attention has also focused on small-molecules capable of reprogramming microglia toward a reparative, surveillance-competent phenotype that enhances Amyloid-β (Aβ) clearance while limiting detrimental neuroinflammation. In this context, we previously reported that Sulfavant A (SULF A), a novel synthetic sulfolipid, binds to Triggering Receptor Expressed on Myeloid Cells 2 (TREM2) and activates myeloid cells without inducing inflammatory hallmarks. The immunomodulatory properties of SULF A were characterized using biochemical, molecular, and cell biological approaches in primary murine microglia. The small modulatory molecule SULF A was synthetically produced in our laboratory. Functional assays included quantitative analyses of phagocytosis using standard beads and fluorescently labeled Aβ peptides, designed and synthesized considering tag emission and fiber aggregation. Aβ aggregation was characterized using biophysical and biochemical methods to ensure well-defined assemblies in microglial assays. To assess translational relevance, SULF A was evaluated at two distinct time points, before and after Aβ plaque deposition, in Tg2576 transgenic mice, a well-established AD model, to determine its neuroprotective potential and therapeutic efficacy. We demonstrate that the small-molecule TREM2 ligand SULF A functions as an immunomodulator that reprograms microglia toward a reparative phenotype. It promotes a ramified and polarized microglial morphology associated with enhanced cellular motility, phagocytic capacity and clearance of neurotoxic Aβ peptides. SULF A upregulates arginase expression, downregulates inducible Nitric Oxide Synthase (iNOS), and redirects microglial metabolism toward tissue-protective functions. This phenotypic shift is characterized by increased TREM2 turnover and upregulation of CD68 and CCL2, without triggering classical inflammatory hallmarks. In vivo, SULF A enhances plaque‑associated microglial recruitment, reduces plaque burden, preserves midbrain dopaminergic neurons, and improves cognitive and motivational performance in Tg2576 mice. We propose that SULF A is a promising therapeutic small molecule that restores microglial homeostasis via an inflammation-sparing mechanism. It enhances amyloid clearance, preserves vulnerable neurons, and improves cognitive function in vivo. These findings support SULF A as a disease-modifying approach that extends beyond conventional plaque-targeting strategies in AD.

Professional antigen-presenting cells (APCs) represent a crucial link between the innate and the adaptive immune response. APCs express specific surface receptors which are primarily involved in “non-self” and/or “self” ligand recognition. Upon ligand binding, these receptors can trigger cell signalling leading to the production of pro-inflammatory cytokines, chemokines and Type 1 interferons, supporting antimicrobial and inflammatory responses. Recently, two major families of receptors, C-type lectin receptors and immunoglobulin receptors, are emerging as potential therapeutic targets to activate and modulate immune system through different intracellular signalling motifs upon binding with endogenous and exogenous ligands. The chemical characterization of the molecular determinants necessary for the receptors/ligands binding promotes the design and optimization of small molecules crucial for the comprehension of biological functions and for the therapeutic treatment of specific receptor-associated disorders. This review focuses on the description of these ligands together with their biological evaluation and their impact on the modulation of the immune response.

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.

In aqueous environment amphiphilic molecules organize themselves into supramolecular structures deeply affecting the chemo-physical properties. Supramolecular assemby is also crucial in the pharmaceutical development of bioactive lipophilic molecules whose attitude to self-aggregate is a recognized factor affecting the in vivo pharmacokinetic, but can also play a crucial role in the interaction with the biological targets in in vitro tests. In aqueous solution, amphiphilic drugs exist in a complex equilibrium involving free monomers, oligomers and larger supramolecular aggregates held together by noncovalent bonds. In this review we focus our attention on the dual effect of drugs self-assembly, which can both reduce the availability of active compounds and create multivalent scaffolds, potentially improving binding affinity and avidity to cellular targets. We examine the effect of aggregation on different classes of amphiphatic molecules with significant biological activities, such as immunomodulatory, anti-tumor, antiviral, and antibiotic.Our purpose is to provide a comprehensive overview of how supramolecular chemistry influences the pharmacological and biological responses of amphiphilic molecules, emphasizing the need to consider these effects in early-stage drug development and in vitro testing. By elucidating these phenomena, this review aims to offer insights into optimizing drug design and formulation to overcome challenges posed by self-aggregation.

Marine invertebrates are a traditional source of natural products with relevant biological properties. Tunicates are soft-bodied, solitary or colonial, sessile organisms that provide compounds unique in their structure and activity. The aim of this work was to investigate the chemical composition of the ascidian Cystodytes dellechiajei, selected on the basis of a positive result in biological screening for ligands of relevant receptors of the innate immune system, including TLR2, TLR4, dectin-1b, and TREM2. Bioassay-guided screening of this tunicate extract yielded two known pyridoacridine alkaloids, shermilamine B (1) and N-deacetylshermilamine B (2), and a family of methyl-branched cerebrosides (3). Compounds 2 and 3 showed selective binding to TREM2 in a dose-dependent manner. N-deacetylshermilamine B (2), together with its acetylated analogue, shermilamine B (1), was also strongly cytotoxic against multiple myeloma cell lines. TREM2 is involved in immunomodulatory processes and neurodegenerative diseases. N-deacetylshermilamine B (2) is the first example of a polycyclic alkaloid to show an affinity for this receptor.

Recently, we described synthetic sulfolipids named Sulfavants as a novel class of molecular adjuvants based on the sulfoquinovosyl-diacylglycerol skeleton. The members of this family, Sulfavant A (1), Sulfavant R (2), and Sulfavant S (3), showed important effects on triggering receptor expressed on myeloid cells 2 (TREM2)-induced differentiation and maturation of human dendritic cells (hDC), through a novel cell mechanism underlying the regulation of the immune response. As these molecules are involved in biological TREM2-mediated processes crucial for cell survival, here, we report the synthesis and application of a fluorescent analogue of Sulfavant A bearing the 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene moiety (Me4-BODIPY). The fluorescent derivative, named PB-SULF A (4), preserving the biological activity of Sulfavants, opens the way to chemical biology and cell biology experiments to better understand the interactions with cellular and in vivo organ targets and to improve our comprehension of complex molecular mechanisms underlying the not fully understood ligand-induced TREM2 activity.

Secondary metabolites play important physiological roles being bioactive as defences against other organisms, or attractive signals used for various purposes, including reproduction. Their production and the emission in the environment may be viewed as an adaptive feature subjected to evolutionary selection. They were demonstrated to be useful for applications in various biotechnological fields, such as pharmaceutical, nutraceutical and cosmeceutical. Sponges and microalgae, including diatoms, are the most promising sources of bioactive compounds from the sea. We aimed at detecting the ecotoxicological effects of crude extracts and fractions obtained from three marine sponges, Geodia cydonium , Haliclona ( Halichoclona ) vansoesti and Agelas oroides and two benthic diatoms, Nanofrustulum shiloi and Cylindrotheca closterium on model marine organisms. We tested their effects on the Mediterranean purple sea urchin, Paracentrotus lividus , and on two diatoms, Phaeodactylum tricornutum and Cylindrotheca closterium , chosen because they are considered standard indicators for assessment of ecological impacts. Our results showed that extracts and fractions from both sponges and diatoms may be harmful for model invertebrates. However, eggs appeared “protected” from sponge allelochemicals when still unfertilized. The majority of sponge fractions exhibited noticeable impacts during the post-fertilization treatments. In contrast, fractions from diatoms notably increased the rate of malformations compared to the control, both in pre- and post-fertilization treatments.

Marine Porifera host diverse microbial communities, which influence host metabolism and fitness. However, functional relationships between sponge microbiomes and metabolic signatures are poorly understood. We integrate microbiome characterization, metabolomics and microbial predicted functions of four coexisting Mediterranean sponges -Petrosia ficiformis, Chondrosia reniformis, Crambe crambe and Chondrilla nucula. Microscopy observations reveal anatomical differences in microbial densities. Microbiomes exhibit strong species-specific trends. C. crambe shares many rare amplicon sequence variants (ASV) with the surrounding seawater. This suggests important inputs of microbial diversity acquired by selective horizontal acquisition. Phylum Cyanobacteria is mainly represented in C. nucula and C. crambe. According to putative functions, the microbiome of P. ficiformis and C. reniformis are functionally heterotrophic, while C. crambe and C. nucula are autotrophic. The four species display distinct metabolic profiles at single compound level. However, at molecular class level they share a "core metabolome". Concurrently, we find global microbiome-metabolome association when considering all four sponge species. Within each species still, sets of microbe/metabolites are identified driving multi-omics congruence. Our findings suggest that diverse microbial players and metabolic profiles may promote niche diversification, but also, analogous phenotypic patterns of "symbiont evolutionary convergence" in sponge assemblages where holobionts co-exist in the same area.

Despite the theoretical high productivity, microalgae-based oil production is not economically sustainable due to the high cost of photoautotrophic cultures. Heterotrophic growth is a suitable economic alternative to overcoming light dependence and climatic/geographic fluctuations. Here we report data about growth performance, biomass production, and lipid composition of the marine diatom Cyclotella cryptica, chosen as a model strain for biodiesel production in heterothrophy. A repeated-batch process of heterotrophic cultivation has also been investigated to assess the robustness and phenotypic stability. The process consisting of six constant cycle repetitions was carried out for 42 days and led to an average dry biomass production of 1.5 ± 0.1 g L-1 of which 20% lipids composed of 60% triglycerides, 20% phospholipids. and 20% glycolipids. The major fatty acids were C16:0 (∼26%), C16:1 ω-7 (∼57%), and C20:5 ω-3 (∼12%), with a significant reduction in the unsaturated fatty acids in comparison to other microalgae grown in heterotrophy. Fatty acids were differently distributed among the glycerolipid classes, and the lipid composition was used to compare the potential properties of C. cryptica oil with traditional vegetable biofuels.

Immunogenic Cell Death (ICD) represents a mechanism of enhancing T cell-driven response against tumor cells. The process is enabled by release of damage-associated molecular patterns (DAMPs) and cytokines by dying cells. Based on molecular studies and clinical marker assessment, ICD can be a new target for cancer chemotherapy hitherto restricted to a few conventional anticancer drugs. In view of the development of small molecules in targeted cancer therapy, we reported the preliminary evidence on the role of the natural product lepadin A ( 1 ) as a novel ICD inducer. Here we describe the ICD mechanism of lepadin A ( 1 ) by proving the translocation of the protein calreticulin (CRT) to the plasma membrane of human A2058 melanoma cells. CRT exposure is an ICD marker in clinical studies and was associated with the activation of the intrinsic apoptotic pathway in A2058 cells with lepadin A ( 1 ). After the treatment, the tumour cells acquired the ability to activate dendritic cells (DCs) with cytokine release and costimulatory molecule expression that is consistent with a phenotypic profile committed to priming T lymphocytes via a CD91-dependent mechanism. The effect of lepadin A ( 1 ) was dose-dependent and comparable to the response of the chemotherapy drug doxorubicin ( 2 ), a well-established ICD inducer.

IntroductionSulfavant A (SULF A) is a synthetic derivative of naturally occurring sulfolipids. The molecule triggers TREM2-related maturation of dendritic cells (DCs) and has shown promising adjuvant activity in a cancer vaccine model.Methodsthe immunomodulatory activity of SULF A is tested in an allogeneic mixed lymphocyte reaction (MLR) assay based on monocyte-derived dendritic cells and naïve T lymphocytes from human donors. Flow cytometry multiparametric analyses and ELISA assays were performed to characterize the immune populations, T cell proliferation, and to quantify key cytokines.ResultsSupplementation of 10 µg/mL SULF A to the co-cultures induced DCs to expose the costimulatory molecules ICOSL and OX40L and to reduce release of the pro-inflammatory cytokine IL-12. After 7 days of SULF A treatment, T lymphocytes proliferated more and showed increased IL-4 synthesis along with downregulation of Th1 signals such as IFNγ, T-bet and CXCR3. Consistent with these findings, naïve T cells polarized toward a regulatory phenotype with up-regulation of FOXP3 expression and IL-10 synthesis. Flow cytometry analysis also supported the priming of a CD127-/CD4+/CD25+ subpopulation positive for ICOS, the inhibitory molecule CTLA-4, and the activation marker CD69.DiscussionThese results prove that SULF A can modulate DC-T cell synapse and stimulate lymphocyte proliferation and activation. In the hyperresponsive and uncontrolled context of the allogeneic MLR, the effect is associated to differentiation of regulatory T cell subsets and dampening of inflammatory signals.

Antarctica is an untapped reservoir of bacterial communities, which are able to adapt to a huge variety of strategies to cope with extreme conditions and, therefore, are capable of producing potentially valuable compounds for biotechnological applications. In this study, 31 UV-resistant bacteria collected from different Antarctic aquatic environments (surface sea waters/ice and shallow lake sediments) were isolated by UV-C assay and subsequently identified. A phylogenetic analysis based on 16S rRNA gene sequence similarities showed that the isolates were affiliated with Proteobacteria, Actinobacteria and Firmicutes phyla, and they were clustered into 15 bacterial genera, 5 of which were Gram negative (Brevundimonas, Qipengyuania, Sphingorhabdus, Sphingobium, and Psychrobacter) and 10 of which were Gram positive (Staphylococcus, Bacillus, Mesobacillus, Kocuria, Gordonia, Rhodococcus, Micrococcus, Arthrobacter, Agrococcus, and Salinibacterium). Strains belonging to Proteobacteria and Actinobacteria phyla were the most abundant species in all environments. The genus Psychrobacter was dominant in all collection sites, whereas bacteria belonging to Actinobacteria appeared to be the most diverse and rich in terms of species among the investigated sites. Many of these isolates (20 of 31 isolates) were pigmented. Bacterial pigments, which are generally carotenoid-type compounds, are often involved in the protection of cells against the negative effects of UV radiation. For this reason, these pigments may help bacteria to successfully tolerate Antarctic extreme conditions of low temperature and harmful levels of UV radiation.

Grapevine (Vitis vinifera L.) can be affected by many different biotic agents, including tracheomycotic fungi such as Phaeomoniella chlamydospora and Phaeoacremonium minimum, which are the main causal agent of Esca and Petri diseases. Both fungi produce phytotoxic naphthalenone polyketides, namely scytalone and isosclerone, that are related to symptom development. The main objective of this study was to investigate the secondary metabolites produced by three Phaeoacremonium species and to assess their phytotoxicity by in vitro bioassay. To this aim, untargeted and targeted LC-MS/MS-based metabolomics were performed. High resolution mass spectrometer UHPLC-Orbitrap was used for the untargeted profiling and dereplication of secondary metabolites. A sensitive multi reaction monitoring (MRM) method for the absolute quantification of scytalone and isosclerone was developed on a UPLC-QTrap. Different isolates of P. italicum, P. alvesii and P. rubrigenum were grown in vitro and the culture filtrates and organic extracts were assayed for phytotoxicity. The toxic effects varied within and among fungal isolates. Isosclerone and scytalone were dereplicated by matching retention times and HRMS and MS/MS data with pure standards. The amount of scytalone and isosclerone differed within and among fungal species. To our best knowledge, this is the first study that applies an approach of LC-MS/MS-based metabolomics to investigate differences in the metabolic composition of organic extracts of Phaeoacremonium species culture filtrates.