Microalgae can modify their metabolic pathways as a response to environmental stimuli such as light, temperature, salinity, and nutrient availability, which critically influence the synthesis of lipids and other biomolecules. While extensive studies have focused on the impact of these environmental variables on the accumulation of valuable compounds such as polyunsaturated fatty acids (PUFAs) and triacylglycerols (TAGs), information on the biosynthesis of specialized metabolites, including long-chain hydroxy fatty acids (LCHFAs), long-chain diols (LCDs), and long-chain alkenols (LCAs) is scarce. These metabolites are thought to contribute to the structural integrity of cell walls in certain microalgae, such as Nannochloropsis spp. (Eustigmatophyceae), where they make up a biopolymer known as algaenan. This study investigates how varying light intensities affect the production of LCHFAs, LCDs, and LCAs in Nannochloropsis oceanica over a 12 h light/dark cycle. Our findings provide insights into the lipid biosynthetic pathways in microalgae, revealing that light strongly drives the production of LCHFAs, whereas LCDs and LCAs are less light-dependent and show more variable responses to different light intensities.

BACKGROUND:Cachexia is a debilitating syndrome associated with involuntary weight loss, often occurring in cancer patients. In both humans and animal models, alterations in endocannabinoid (eCB) signaling occur in association with both metabolic disorders and several types of tumors. The wider signaling system, including the two eCBs, anandamide (AEA) and 2-arachidonoyl-glycerol (2-AG), their congeners and other long chain fatty acid amides, as well as their metabolic enzymes and receptors, is known as endocannabinoidome (eCBome). The eCBome is involved, among others, in the control of energy balance and cancer and interacts with the gut microbiome. METHODS:Using mass spectrometry-based targeted lipidomics, we measured the hepatic and intestinal concentrations of eCBome mediators in mice injected with colon carcinoma 26 (C26) cells, a model of cancer cachexia characterized, among others, by weight loss, hepatic dyslipidemia, and gut microbiome dysbiosis. RESULTS:We report that, 10 days after C26 cell injection, concomitant with >10% weight loss, eCBome lipids levels, namely 2-AG, AEA, and some of its N-acyl-ethanolamine congeners, as well as N-oleoyl-glycine, N-acyl-serotonins, and N-acyl-taurines (NATs), are altered in intestinal sections and the liver of C26 mice (e.g., hepatic 2-AG -30%, jejunal 2-AG + 30%, jejunal AEA -55%, hepatic N-oleoyl-ethanolamine (OEA) + 223%, hepatic NATs +144%, +141%, +216%). Gut dysbiosis was evident in these mice (PERMANOVA at the family level: R² = 69%, p < 0.001), with altered levels in 3 phyla (mainly the Proteobacteria, +1484%), 12 families, and 12 genera (all with adjusted p < 0.05). Additionally, 2-AG, AEA, OEA, N-arachidonoyl-serotonin, and NAT levels in the liver positively correlated with hepatic total lipids, triglycerides, and cholesterol, whereas N-docosahexaenoyl-ethanolamine and N-docosahexaenoyl-serotonin showed negative correlations. Jejunal AEA negatively, and hepatic OEA and NATs positively, correlated with weight loss. Intestinal eCBome mediators correlated with several cecal microbial taxa, including genera known to include strains beneficial in metabolic disorders, such as Bacteroides, Parabacteroides, Dysosmobacter, and Prevotella. CONCLUSIONS:These observations pinpoint eCBome mediators as new multi-functional players in the hepatic complications and gut dysbiosis accompanying cancer cachexia.

Global change is producing significant ecological impacts in Antarctic marine organisms, although most of them are still understudied. Here, we report the changes in the chemical profile of the colonial tunicate Synoicum adareanum in response to gradual temperature increases in controlled aquarium experiments as a proxy to determine the effects of global warming. This is the first study on the effects of increasing seawater temperature on the natural products of an Antarctic tunicate. From specimens collected at Livingston Island in the South Shetland Islands in January 2022, we isolated the known palmerolides A, B, D, F, and H (1-5). Palmerolides are a family of macrolides which are considered to play a defensive role against natural predators and exhibit also very potent pharmacological bioactivities. Our metabolomic study based on UPLC-HRESI-MS analysis demonstrated the impact of increasing temperatures on the natural products of S. adareanum, with a significant and massive increment of the amounts of all palmerolides as well as the onset of tunic necrosis at 4-5 °C. Further understanding these mechanisms at the molecular level in Antarctic marine benthic organisms may offer insights into how these ecosystems may respond to global change.

The waters around the western Antarctic Peninsula are experiencing fast warming due to global change, being among the most affected regions on the planet. This polar area is home to a large and rich community of benthic marine invertebrates, such as sponges, tunicates, corals, and many other animals. Among the sponges, the bright yellow Dendrilla antarctica is commonly known for using secondary diterpenoids as a defensive mechanism against local potential predators. From the dichloromethane extract of sponge samples from Deception Island collected in January 2023, we isolated a novel derivative with an unusual β-lactone diterpene skeleton here named dendrillolactone (1), along with seven previously described diterpenes, including deceptionin (2), a gracilane norditerpene (3), cadlinolide C (4), a glaciolane norditerpene (5), membranolide (6), aplysulphurin (7), and tetrahydroaplysulphurine-1 (8). Here, we also report our studies on the changes in the chemical arsenal of this sponge by slow temperature increase in aquaria experiments. Despite being a species capable of inhabiting volcanically active areas, with frequent water temperature fluctuations due to the existing fumaroles, the results show that diterpenes such as deceptionin, cadlinolide C, membranolide, and tetrahydroaplysulphurin-1 seem to be susceptible to the temperature increase, resulting in a trend to higher concentrations. However, temperatures above 4 °C severely affected sponge metabolism, causing its death much earlier than expected. Further research on the roles of these natural products in D. antarctica and their relationship to the sponge’s resilience to environmental changes should help to better understand the defensive mechanisms of Antarctic marine benthos in the context of global change.

The artichoke (Cynara cardunculus L. subsp. scolymus) is an endemic perennial plant of the Mediterranean area commonly consumed as food. It is known since ancient times for its beneficial properties for human health, among which its antioxidant activity due to polyphenolics stands out. In the frame of our ongoing studies aiming to highlight the biodiversity and the chemodiversity of natural resources, we investigated the phenolic and saponin content of the cultivar “Carciofo di Procida” collected at Procida, an island of the Gulf of Naples (Italy). Along with the edible part of the immature flower, we included in our analyses the stem and the external bracts, generally discarded for food consuming or industrial preparations. The LCMS quali-quantitative profiling of polyphenols (including anthocyanins) and cynarasaponins of this cultivar is reported for the first time. In addition to antioxidant properties, we observed a significant cytotoxic activity due to extracts from external bracts against human neuroblastoma SH-SY5Y cell lines with 43% of cell viability, after 24 h from the treatment (50 μg/mL), and less potent but appreciable effects also against human colorectal adenocarcinoma CaCo-2 cells. This suggests that the different metabolite composition may be responsible for the bioactivity of extracts obtained from specific parts of artichoke and foresees a possible exploitation of the discarded material as a source of beneficial compounds.

Quorum sensing (QS) is a bacterial cell-to-cell communication induced at high cell density, commonly involved in regulating gene expression of spoilage and pathogenic virulence factors. In dairy products, Pseudomonas species grow under cold conditions and produce thermostable proteases. The QS pathway in Pseudomonas represents a potential target to limit protease synthesis during raw milk storage prior to heat processing. This study aims to characterize AHL-mediated QS system in highly proteolytic Pseudomonas isolated from raw milk and to explore the use of polyphenols as a strategy to control proteolytic activity. Six isolates with high proteolytic activity were identified as Pseudomonas gessardii by Matrix-Assisted Laser Desorption/Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) and 16S rRNA sequencing. Biosensor strains, thin layer chromatography-overlay assay, and ultra performance liquid chromatography-mass spectrometry (UPLC-MS) analysis were used to explore QS, revealing C4-HSL as the main type of AHL produced by P. gessardii. Salicylic acid (SA), cinnamaldehyde (CIN), and tannic acid (TA) were tested as QS inhibitors (QSIs) and the mechanism verified by in silico analysis. Various degrees of proteolytic activity inhibition were observed at 4 °C and 25 °C by using QSIs (15-58 % by SA, 10-60 % by CIN), with no antibacterial effect. The mechanism behind that is the competition with the C4-HSL to bind with the receptor protein (LuxR) as corroborated by the in silico analysis. The results highlight the potential to employ polyphenols to restrict proteolytic activity by psychrotrophic Pseudomonas in dairy products.

Pancreatic cancer is one of the most aggressive tumours with poor prognosis and low year survival rate. Marine sponges are considered a challenging source of bioactive compounds, as potential drugs for cancer treatments. Here we report a bioassay-guided investigation of the methanolic extract of the sponge Agelas oroides (Schmidt, 1864), which displayed a potent cytotoxic activity against pancreatic adenocarcinoma (MIA PaCa-2 cells with <40% viability at 1 µg/ml). Two-step fractionation of the extract by SPE-HRX and RP-HPLC led to the identification of brominated pyrrole alkaloids as the chemical constituents of one of the most active fractions (IC50 = 34 µg/ml). Among these, we identified the 4,5-dibromopyrrole-2-carboxylic acid as the bioactive product (IC50 = 10 µg/ml). Our results disclose for the first time the sponge A. oroides as a source of cytotoxic alkaloids targeting pancreatic cancer and provide a contribute to the development of alternative strategies for the treatment of these severe pathologies.

Quorum sensing (QS) is a cell-to-cell signaling system that takes place at a key concentration (quorum) of signal molecules and via a peculiar signaling pathway. Both bacteria and yeasts possess QS mechanisms, mediated by specific molecules (farnesol, tyrosol, 2-phenylethanol, tryptophol) in yeasts, and N-acylhomoserine lactones (AHLs) and modified oligopeptides in bacteria. Here, we report the first chemical evidence of bacterial QS activity in yeast Saccharomyces cerevisiae (OS3 and V5 strains) by UPLC-MS/MS identification of N-octanoyl- and N-decanoyl-L-homoserine lactones in cell-free culture media extracts. The AHLs' presence was unexpected, as they are produced exclusively by bacteria. Tyrosol, a yeast signal molecule, was identified and quantified by NMR analysis. Metataxonomic analysis suggested the existence inside S. cerevisiae cells of bacteria, including Firmicutes, Bacteroidota, and Proteobacteria. Our study paves the way for investigations into bacterial detection within S. cerevisiae cells and their role in biotechnological performance in the food fermentation fields.

Microalgae are currently considered an attractive source of highly valuable metabolites potentially exploitable as anticancer agents, nutraceuticals and cosmeceuticals and for bioenergy purposes. Their ease of culturing and their high growth rates further promote their use as raw material for the production of specialty products. In the present paper, we focused our attention on specific glycerol-based lipid compounds, monoacylglycerols (MAGs), which displayed in our previous studies a selective cytotoxic activity against the haematological U-937 and the colon HCT-116 cancer cell lines. Here, we performed a quali/quantitative analysis of MAGs and total fatty acids (FAs) along with a profiling of the main lipid classes in a panel of 12 microalgal species, including diatoms and dinoflagellates. Our results highlight an inter- and intraspecific variability of MAG profile in the selected strains. Among them, Skeletonema marinoi (strain FE7) has emerged as the most promising source for possible biotechnological production of MAGs.

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.

The increasing prevalence of sleep deprivation in modern society demands comprehension of the biological consequences of sleep loss on brain functioning. Our study reveals significant effects of sleep deprivation on myelin integrity. As a result, we identify increased conduction delays in nerve signal propagation, hindered interhemispheric synchronization, and impaired motor performance associated with sleep loss. By profiling oligodendrocyte transcriptome and lipidome, we observe sleep loss-induced endoplasmic reticulum stress and lipid metabolism disruption, particularly affecting cholesterol homeostasis. This shift in cholesterol levels alters myelin physical properties. Boosting cholesterol transport to myelin sheaths prevents sleep loss effects on nerve signal propagation and behavior. Our findings highlight the critical role of oligodendrocyte cholesterol regulation in behavioral deficits associated with sleep loss and unveil a novel target for intervention.

Lipases are promising improvers of cake batter and baking properties. Their suitability for use in various cake formulations cannot be predicted yet, because the reactions that lead to macroscopic effects need to be unravelled. Therefore, the lipidome of three different cake recipes with and without lipase treatment was assessed by ultra high performance liquid chromatography-mass spectrometry before and after baking. By comparing the reaction patterns of seven different lipases in the recipes with known effects on texture, we show that lipase substrate specificity impacts baking quality. Key reactions for the recipes were identified with the help of principal component analysis. In the eggless basic cake, glyceroglycolipids are causal for baking improvement. In pound cake, lysoglycerophospholipids were linked to textural effects. Lipase substrate specificity was shown to be dependent on the recipe. Further research is needed to understand how recipes can be adjusted to achieve optimal lipase substrate specificity for desirable batter and baking properties.

Fatty acids (FAs) are used, often in combination with stable isotopes (SIs), as chemical biomarkers to assess the contribution of different prey to the diet of consumers and define food web structure and dynamics. Extraction of lipids is traditionally carried out using methanol (MeOH) combined with chloroform or dichloromethane, these latter being well-known environmental pollutant and potential carcinogenic agents. Recently, extraction protocols based on methyl tert-butyl ether (MTBE) and MeOH have been proposed as an alternative to halogenated solvents in lipidomic studies. However, no specific investigation has been performed to assess MTBE suitability in marine ecological studies including FA analysis together with SI measurements. We used an analytical workflow for qualitative and quantitative analysis of FAs and SIs in field samples of phytoplankton, zooplankton and the scyphomedusa Pelagia noctiluca, applying MTBE in comparison with chloroform- and dichloromethane-based protocols for total lipid extraction. Our analysis suggested that MTBE is a reliable substitute for lipid extraction in trophic ecology studies in marine planktonic organisms.

The recent discovery of N-acyl taurines (NATs) as a class of endogenous bioactive lipids and the perspective of their possible pharmacological applications stimulated the development of mass spectrometry-based methods for their quantitative measurements in biological tissues and fluids. We report here for the first time a procedure validated both in liver surrogate matrix and neat solvent (MeOH) based on UPLC-ESI-QqQ analysis for the identification and quantification of NATs in biological tissue extracts. The LC-MS method was based on five representative lipid analogues, including saturated, monounsaturated and polyunsaturated species, namely N- palmitoyl taurine (C16:0 NAT), N-oleoyl taurine (C18:1 NAT), N-arachidonoyl taurine (C20:4 NAT), N-docosa-noyl taurine (C22:0 NAT) and N-nervonoyl taurine (C24:1 NAT), and evaluated for specificity, linearity, matrix effect, recovery, repeatability and intermediate precision and accuracy. The method validated in MeOH by in-ternal standard approach (d4-C20:4 NAT) showed excellent linearity in the range 1-300 ng/ml with R always >= 0.9996 for all NATs; intra-day and inter-day precision and accuracy were always within the acceptable range. Specificity was assessed on NAT standards in MeOH, applying the confirmation ratio of two diagnostic MRM ion transitions for product ions at m/z 80 and m/z 107 to true samples in the adopted BEH C18 UPLC conditions. Limit of detection (LOD) and limit of quantification (LOQ) were 0.3-0.4 and 1 ng/ml, respectively, for all compounds. The method was successfully applied to assess the levels of NATs in the mouse liver and, for the first time, in varying sections of the intestine (duodenum, jejunum, ileum and colon). NAT levels increased from duodenum to colon, evidencing a remarkable prevalence in the large intestine of C22:0 NAT, typically occurring mainly in the central nervous system. These findings prompt further studies to disclose the biological function of the various members of this class in different peripheral tissues.

There is a strong need to develop eco-sustainable agricultural techniques to improve crop yields while preserving biomolecule contents and reducing the adverse environmental impact of agro-chemicals. The use of microorganisms in agriculture represents an attractive and innovative solution. Herein, a chemical study on the nutritional and sensory qualities of San Marzano Cirio 3 (SMC3), Corbarino (CO) and Brandywine (BW) tomato varieties cultivated with and without effective microorganisms (EM) is reported. LC–MS analysis of the methanolic extracts allowed for the identification of 21 polyphenol derivatives. In different proportions among the studied varieties, the two main polyphenols were rutin and naringenin chalcone; the latter was isolated and chemically identified by complementary HR-ESIMS/MS and NMR methods. SMC3 and CO were richer in naringenin chalcone. Conversely, BW showed higher proportions of rutin; however, in all cases, the relative amounts of the two polyphenols considered together increased over the other minor components after the EM treatment. The qualitative and quantitative HPLC analyses of taste-active compounds (aspartic acid, glutamic acid, AMP and GMP) revealed a significant difference in aspartic and glutamic acids and ribonucleotide contents according to the cultivation condition (±EM), particularly in BW. This study provides chemical data in support of the use of EM green technology for the cultivation of edible agricultural products, such as tomato preserves, and may even improve nutritional and sensory qualities while safeguarding the environment.

Marine sponges usually host a wide array of secondary metabolites that play crucial roles in their biological interactions. The factors that influence the intraspecific variability in the metabolic profile of organisms, their production or ecological function remain generally unknown. Understanding this may help predict changes in biological relationships due to environmental variations as a consequence of climate change. The sponge Dendrilla antarctica is common in shallow rocky bottoms of the Antarctic Peninsula and is known to produce diterpenes that are supposed to have defensive roles. Here we used GC-MS to determine the major diterpenes in two populations of D. antarctica from two islands, Livingston and Deception Island (South Shetland Islands). To assess the potential effect of heat stress, we exposed the sponge in aquaria to a control temperature (similar to local), heat stress (five degrees higher) and extreme heat stress (ten degrees higher). To test for defence induction by predation pressure, we exposed the sponges to the sea star Odontaster validus and the amphipod Cheirimedon femoratus. Seven major diterpenes were isolated and identified from the samples. While six of them were already reported in the literature, we identified one new aplysulphurane derivative that was more abundant in the samples from Deception Island, so we named it deceptionin (7). The samples were separated in the PCA space according to the island of collection, with 9,11-dihydrogracilin A (1) being more abundant in the samples from Livingston, and deceptionin (7) in the samples from Deception. We found a slight effect of heat stress on the diterpene profiles of D. antarctica, with tetrahydroaplysulphurin-1 (6) and the gracilane norditerpene 2 being more abundant in the group exposed to heat stress. Predation pressure did not seem to influence the metabolite production. Further research on the bioactivity of D. antarctica secondary metabolites, and their responses to environmental changes will help better understand the functioning and fate of the Antarctic benthos.

Aquatic invertebrates are a major source of biomaterials and bioactive natural products that can find applications as pharmaceutics, nutraceutics, cosmetics, antibiotics, antifouling products and biomaterials. Symbiotic microorganisms are often the real producers of many secondary metabolites initially isolated from marine invertebrates; however, a certain number of them are actually synthesized by the macro-organisms. In this review, we analysed the literature of the years 2010–2019 on natural products (bioactive molecules and biomaterials) from the main phyla of marine invertebrates explored so far, including sponges, cnidarians, molluscs, echinoderms and ascidians, and present relevant examples of natural products of interest to public and private stakeholders. We also describe omics tools that have been more relevant in identifying and understanding mechanisms and processes underlying the biosynthesis of secondary metabolites in marine invertebrates. Since there is increasing attention on finding new solutions for a sustainable large-scale supply of bioactive compounds, we propose that a possible improvement in the biodiscovery pipeline might also come from the study and utilization of aquatic invertebrate stem cells.

Ocean acidification (OA) is a dramatic perturbation of seawater environments due to increasing anthropogenic emissions of CO2. Several studies indicated that OA frequently induces marine biota stress and a reduction of biodiversity. Here, we adopted the macroalga Ulva prolifera as a model and applied a complementary multi-omics approach to investigate the metabolic profiles under normal and acidified conditions. Our results show that U. prolifera grows at higher rates in acidified environments. Consistently, we observed lower sucrose and phosphocreatine concentrations in response to a higher demand of energy for growth and a higher availability of essential amino acids, likely related to increased protein biosynthesis. In addition, pathways leading to signaling and deterrent compounds appeared perturbed. Finally, a remarkable shift was observed here for the first time in the fatty acid composition of triglycerides, with a decrease in the relative abundance of PUFAs towards an appreciable increase of palmitic acid, thus suggesting a remodeling in lipid biosynthesis. Overall, our studies revealed modulation of several biosynthetic pathways under OA conditions in which, besides the possible effects on the marine ecosystem, the metabolic changes of the alga should be taken into account considering its potential nutraceutical applications.

The invasive macroalga Caulerpa cylindracea has spread widely in the Mediterranean Sea, becoming a favorite food item for native fish for reasons yet unknown. By using a combination of behavioral, morphological, and molecular approaches, herein we provide evidence that the bisindole alkaloid caulerpin, a major secondary metabolite of C. cylindracea, significantly increases food intake in the model fish Danio rerio, influencing the regulation of genes involved in the orexigenic pathway. In addition, we found that the compound improves fish reproductive performance by affecting the hypothalamus–pituitary–gonadal axis. The obtained results pave the way for the possible valorization of C. cylindracea as a sustainable source of a functional feed additive of interest to face critical challenges both in aquaculture and in human nutrition.