Search Results (632)

Marine microbiomes play an important role in coastal marine environments. This study examined microbial communities in beach waters and sands at six recreational beaches to identify the fingerprints of anthropogenic influences. Samples were collected from four metropolitan areas in the U.S., within Miami, Florida; Seattle, Washington; Newport Beach, California and in Australia within Adelaide. Samples were analyzed for enterococci and fungi by culture. Reverse-transcription droplet digital PCR (RT-ddPCR) was performed for pepper mild mottle virus (PMMoV). Next-generation sequencing was carried out to elucidate the microbial diversity and predict antibiotic resistance. Enterococci concentrations surpassed the U.S. EPA marine water quality guideline value in the seawater samples from Seattle and Adelaide, and fungal concentration exceeded the WHO guideline in the sand of North Star Beach, California. Low levels of PMMoV were detected in seawater and sand from multiple locations. Chloroflexi and Acidobacteria were the most abundant bacterial phyla in sand, while Marinimicrobia and Cyanobacteria dominated in seawater. Beach sand had higher bacterial and fungal diversity than seawater, of which the most abundant fungal genera include taxa of potential pathogens. Predicted antibiotic resistance genes showed high levels of beta-lactam and multidrug resistance genes in all samples. This study contributes to the understanding of anthropogenic impact on the coastal environment, emphasizing the need for human health protection measures. Full article

Planktothrix species are among the most widespread bloom-forming cyanobacteria in freshwater ecosystems and are of particular concern because of their ability to produce cyanotoxins and form persistent harmful algal blooms (HABs). Among them, Planktothrix agardhii and Planktothrix rubescens are the most extensively studied species and are responsible for a large proportion of bloom events reported in European lakes. This review synthesizes current knowledge on the taxonomy, ecophysiology, toxin production, environmental drivers, species interactions, and management of Planktothrix blooms, with a particular focus on European freshwater ecosystems. The available evidence highlights marked ecological differences between the two dominant species. P. agardhii is primarily associated with shallow, eutrophic, and well-mixed lakes, whereas P. rubescens is typically found in deep, stratified, and relatively transparent water bodies, where it forms persistent metalimnetic populations. These contrasting ecological strategies influence bloom development, toxin dynamics, detection, and management. Nutrient availability, light climate, temperature, water column stability, and biological interactions all contribute to bloom establishment and persistence, while climate change is expected to further modify bloom frequency, duration, and geographic distribution. The review also examines current monitoring and mitigation approaches, highlighting the limitations of conventional surface-based surveys for detecting deep P. rubescens populations and emphasizing the need for integrated monitoring strategies combining depth-resolved sampling, molecular tools, and toxin analyses. Overall, understanding the ecological and physiological diversity of Planktothrix species is essential for improving risk assessment, developing effective management measures, and mitigating the impacts of cyanobacterial blooms in European freshwaters. Full article

Microbiologically induced concrete corrosion (MICC) poses a severe challenge to the long-term durability of infrastructure, particularly in sewer networks and marine environments, which is driven by microbial metabolic activities that attack cement hydrates (Ca(OH)₂, C-S-H) mainly caused by biogenic sulfuric acid (from sulfur-oxidizing bacteria) or organic acids (from fungi), converting them into expansive gypsum and ettringite, and then cause cracking and spalling. This article reviews advances in mechanisms, key microorganisms, and protection strategies of MICC to enhance our understanding of MICC and provide a guideline for effective protection. The corrosion mechanisms differ by environment: sewers exhibit three-stage pH-driven succession, marine biofilms can either accelerate or inhibit corrosion, while fungi dominate in agricultural and historical settings. Core functional microorganisms involved in MICC include sulfur-oxidizing bacteria (SOB), sulfate-reducing bacteria (SRB), and acid-producing fungi (AF), following pH-dependent succession, while indicator microorganisms for protection efficacy include typical SOB, SRB, and AF that are involved in MICC, as well as general antimicrobial indicator strains (e.g., Escherichia coli and Staphylococcus aureus) which are used only to assess broad antimicrobial activity and do not represent MICC-specific resistance. Multi-scale deterioration proceeds from microstructural decalcification and pore coarsening to macroscopic mass loss and compressive strength reduction. Protection strategies are categorized into: (i) corrosion-resistant materials (e.g., calcium aluminate cement and alkali-activated materials), (ii) antimicrobial additives (e.g., nano-ZnO and Cu₂O), (iii) surface coatings (e.g., superhydrophobic coatings and electrodeposited Cu/Cu₂O layers), and (iv) ecological regulation. However, significant gaps remain between laboratory efficacy and field performance, highlighting the need for long-term validation, multi-scale characterization, intelligent responsive materials, eco-compatible protection systems, and standardized microbial exposure systems. Full article

Hydroperoxides (R–OOH, organic hydroperoxides) constitute a relatively small but structurally diverse class of natural metabolites occurring in higher plants, fungi, and marine organisms. Their formation is closely associated with oxidative processes involving redox-active metal ions, particularly iron and copper, which promote reactive oxygen species (ROS) generation and the oxidative transformation of steroids and triterpenoids. In the present study, approximately 1500 naturally occurring steroids and triterpenoids were screened using the PASS (Prediction of Activity Spectra for Substances) platform to identify compounds with potential relevance to neurodegenerative disorders. Among the analyzed compounds, only 17 hydroperoxide-containing steroids and triterpenoids exhibited notable predicted anti-dementia activity and were selected for detailed evaluation. The selected compounds displayed a broad spectrum of predicted biological activities, including antineoplastic, anti-inflammatory, antiulcerative, antithrombotic, hepatoprotective, and neuroprotective effects. Several hydroperoxide-containing triterpenoids demonstrated particularly high predicted anti-dementia activity, with a norlupane-type hydroperoxide exhibiting the highest probability of activity (Pa = 0.972). The biological significance of these compounds may be related to the unique redox properties of the hydroperoxide functionality, which can participate in both oxidative and adaptive signaling processes. Because hydroperoxides interact with transition metal ions and reactive oxygen species, they occupy a complex position at the interface between oxidative stress, cellular defense mechanisms, and neurodegeneration. The present analysis highlights hydroperoxide-containing steroids and triterpenoids as an underexplored class of natural products with potential relevance to dementia research. However, the reported activities are based primarily on computational predictions and should be interpreted as indicators of pharmacological potential rather than experimentally validated therapeutic effects. Further investigations involving blood–brain barrier permeability assessment, biochemical studies, cellular assays, animal models, and clinical evaluation will be required to determine the true therapeutic value of these compounds in neurodegenerative diseases. Full article

The Bahía Blanca marshes are highly productive ecosystems that act as carbon sinks and support a diverse community of halophytic plants, including species of Distichlis, Spartina, Sarcocornia, among others. Marine fungi inhabit these ecosystems and play important roles in the decomposition of organic matter and the production of valuable biopolymers and metabolites. Despite their potential ecological and commercial importance, little is known about the identity and chemical profiles of these fungi associated with marine environments and halophytic plants in the Bahía Blanca estuary. To expand current knowledge of marine fungi in this system, three fungal species associated with marine waters and Sarcocornia perennis plants were isolated and identified: Aspergillus iizukae, Stemphylium sp. (Ascomycota), and Mucor sp. (Mucoromycota). Their biomass was analyzed to determine its biochemical and metabolic composition. Stemphylium sp. exhibited the highest protein (30.24 g/100 g dry mass) and lipid (2.65 g/100 g dry mass) contents, whereas Mucor sp. showed the highest levels of total sugars (26.13 g/100 g dry mass) and glucosamine (17.30 g/100 g dry mass). Aspergillus iizukae produced the greatest diversity of secondary metabolites. These findings provided a preliminary characterization of fungal species from this region and highlighted their potential for future biotechnological and industrial applications. Full article

Thirteen new decaline polyketides, namely, zosteropenillines T–W (1–4), 8-hydroxypallidopenilline A (5), 13-epi-zosteropenilline P (6), 11-epi-zosteropenilline N (7), 15-hydroxyzosteropenilline M (8), 8-hydroxyzosteropenilline M (9), 11-epi-zosteropenilline M (10), and zosteropenillines X–Z (11–13), along with 17 known related compounds (14–30) were isolated from the ethyl acetate extract of the marine-derived fungus Penicillium yezoense KMM 4679 cultivated on MgCl₂-containing nutrient medium. The structures of the isolated compounds were established based on spectroscopic methods. The absolute configurations of zosteropenillines T (1) and V (3) were determined using time-dependent density functional theory (TD-DFT) calculations of the ECD spectra. X-ray diffraction analysis data were obtained for the known zosteropenilline S (28). A biogenetic pathway for 1–13 was proposed. The effects of the compounds on Staphylococcus aureus and Candida albicans growth and biofilm formation were observed. Zosteropenillines U (2), Y (12) and Z (13) with higher activity against C. albicans biofilms were nontoxic for normal cardiomyocyte H9c2 cells, making them promising anti-candidal agents. Moreover, zosteropenillines U and Y demonstrated cardioprotective effects in acute ischemia/reperfusion and CoCl₂-mimicking hypoxia in vitro models. Full article

Objectives: This study aimed to isolate secondary metabolites from sea cucumber-associated fungus Trichoderma koningii KMM 4751, obtain their bromine derivatives, and investigate their antimicrobial and cytotoxic activities. Results: 3-Ethyl-4-hydroxy-6-methyl-2H-pyran-2-one (EHMP) was isolated from fungal extract. It was brominated, and a previously unreported 6-(bromomethyl)-3-ethyl-4-hydroxy-2H-pyran-2-one (Br-EHMP) was obtained. EHMP inhibited the formation of Candida albicans biofilms with an IC₅₀ of 49.3 µM, but Br-EHMP was less active. Simultaneously, bromination of EHMP significantly enhanced the inhibitory effect of Br-EHMP on Staphylococcus aureus growth and biofilm formation without increasing cytotoxicity to H9c2 cells. Br-EHMP at 10 μM can inhibit sortase A activity by near 30% in a cell-free assay. In silico molecular docking predicted the interaction of Br-EHMP with Cys184 in the sortase A active site. Conclusions: Br-EHMP emerges as a promising antibiofilm agent, and its mechanism involves sortase A inhibition. Full article

Microbial pigments are secondary metabolites that represent promising alternatives to synthetic colorants, offering advantages even over other natural sources. These pigments can be produced independently of seasonality and at low cost, especially when using agro-industrial residues as substrates, and their production can be optimized. Bioprospecting of microorganisms in unexplored environments offers valuable opportunities to discover safer and more efficient pigment producers. Brazil harbors vast biodiversity across multiple biomes, providing a rich reservoir for such discoveries. Biomes such as the Atlantic Forest, Pampa, Pantanal and Coastal Marine are still poorly explored with respect to the bioprospecting of pigment-producing microorganisms, representing a valuable opportunity for the discovery of novel pigments. However, several bottlenecks still hinder the regulatory approval of microbial pigments, particularly those produced by filamentous fungi, due to the frequent co-production of mycotoxins. To overcome these challenges, genetic engineering tools are crucial for eliminating mycotoxin co-production. CRISPR-Cas9, CRISPRi and CRISPR-Cpf1 have become the most widely used techniques for this purpose. Another key application of CRISPR is the enhancement of pigment yields, which can accelerate the industrial adoption of microbial pigments. Together, these two strategies, bioprospecting new environments and genetic engineering, can significantly speed up the transition from synthetic pigments to safer and more eco-friendly microbial alternatives. Full article

Marine endophytic fungi inhabit the internal tissues of seaweed, seagrass, and mangroves without causing harm. These fungi are known to produce extracellular enzymes, including proteases and cellulases, which play crucial roles in various biological processes and have potential applications in diverse industrial sectors. This study aimed to screen the enzymatic potential of marine endophytic fungi, identify selected isolates, and characterize their enzyme activities. A total of 20 fungal isolates were obtained, comprising 16 isolates from seaweed, three from seagrass, and one from mangrove leaves, collected from the coastal areas of the Seribu Islands (Jakarta), Sukabumi (West Java), Nusa Dua (Bali), and the Buton Islands (Southeast Sulawesi). Screening results showed that 50% of the isolates exhibited proteolytic activity on skim milk agar, while 40% demonstrated cellulolytic activity on carboxymethylcellulose (CMC) agar. Two isolates with the highest clear zone indices for protease and cellulase activity were identified as Penicillium citrinum and Fomitopsis sp., with distinct morphological characteristics including velvety colonies and filamentous hyphal structures. The specific activities of the protease and cellulase were 5475.42 ± 2724.25 U/mg protein and 620.77 ± 607.71 U/mg protein, respectively, indicating high catalytic potential. Full article

In recent years, Marine Natural Products (MNPs) have emerged as a significant source for anticancer drug discovery, as many natural products can offer structural diversity, unique mechanisms of action, and relatively low toxicity. This article provides a systematic review of MNPs with reported anticancer activities from 2020 to 2024. These compounds are classified into seven major categories: terpenoids, alkaloids, sterols, polyketides, peptides and proteins, polysaccharides, and macrolides. For each category, we elaborate on the marine sources, structural identification, in vitro anticancer activity, and preliminary structure–activity relationships. We found that sponges and marine-derived fungi are the most abundant sources of highly active compounds. Furthermore, knowledge graph-based analysis reveals that oxygen- and nitrogen-containing heterocycles constitute the core pharmacophores, and target prediction further indicates that MNPs exert anticancer effects through coordinated modulation of a multi-target network involving kinases, proteasomes, and nuclear receptors. This review contributes significantly to a deeper understanding of recent advances (2020–2024) in MNPs and provides critical guidance for promoting the development of innovative anticancer drugs derived from marine resources. Full article

Naphthopyranones represent a structurally diverse family of fungal polyketides exhibiting a broad range of biological activities, including antibacterial, antifungal, and cytotoxic properties. Despite extensive investigations of terrestrial-derived naphthopyranones, the biosynthetic machinery responsible for their production in marine fungi has remained unexplored. Here, we report the first characterization of naphthopyranone biosynthetic gene clusters (BGCs) from a deep-sea-derived fungus. Genome mining of the cold seep-associated Penicillium javanicum OUCF108 revealed two highly homologous polyketide synthase gene clusters, pig1 and pig2. Comparative transcriptomics combined with targeted disruption of the core PKS gene pigA2 demonstrated that pig2 is the essential BGC responsible for (R)-semivioxanthin (1) production. Stepwise reconstruction of the pig2 pathway in Aspergillus oryzae NSAR1 unraveled the complete biosynthetic route from the heptaketide precursor nor-toralactone (2) to (R)-semivioxanthin (1) and its dimeric derivatives. In vitro biochemical characterization revealed that the O-methyltransferase PigN2 catalyzes regioselective 6-O-methylation with relaxed substrate specificity, that the laccase PigF2 mediates oxidative dimerization of 1 to afford dimeric derivatives, and that the fasciclin-like protein PigG2 alters this default regiochemistry, affording abundant alternative regioisomeric dimers alongside the 5,5′-linked product. Notably, a new naphthopyranone derivative, nor-4-hydroxy-toralactone (4), was isolated and structurally elucidated. Antimicrobial evaluation of all isolated compounds revealed that 4 exhibits moderate antifungal activity against the multidrug-resistant pathogen Candida auris (MIC = 12.5 μg mL⁻¹). Structure–activity relationship analysis identified the C-4 hydroxyl moiety is critical for activity. This study highlights the potential of deep-sea fungi as an untapped reservoir of bioactive naphthopyranones and provides enzymatic insights for the construction of regioselectively coupled biaryl scaffolds. Full article

Polysaccharides are structurally diverse biopolymers composed of multiple monosaccharide units linked through glycosidic bonds. Their complexity, biodegradability, and functional versatility make them integral to biological systems as well as modern industrial application. Sourced from plants, fungi, marine organisms, animals, and microbes, these natural polymers exhibit a broad spectrum of bioactivities, including antioxidant, antimicrobial, immunomodulatory, and physicochemical protective functions. In the context of food preservation, polysaccharides have gained significant attention as sustainable alternatives to synthetic preservatives and conventional packaging materials. This review summarizes the classification and structural attributes of polysaccharides that influence their functional performance, particularly their ability to scavenge free radicals, inhibit foodborne pathogens, and form protective barrier systems. Special emphasis is placed on their use in edible films, coatings, and encapsulation systems that enhance the shelf life of fruits, vegetables, meats, dairy, beverages, and bakery products. Challenges related to stability, sensory impact, and regulatory compliance are also discussed. Overall, polysaccharides demonstrate substantial potential as eco-friendly, bioactive packaging agents and controlled-release carriers, contributing to safer, greener, and more sustainable food preservation technologies. Full article

Alzheimer’s disease (AD) is characterized by amyloid-β deposition, neuroinflammation, and mitochondrial dysfunction. Phosphodiesterase 4 (PDE4), a key regulator of cyclic nucleotides in neurons, represents a promising therapeutic target for AD. In this study, we performed a PDE4 inhibition-guided screen of an in-house marine natural product library derived from marine fungi, leading to the identification of a sesterterpenoid variecolactone (VLT) as a potent PDE4 inhibitor. VLT exhibited selective PDE4D inhibition (IC₅₀ = 2.302 μM) with minimal activity against other PDE subtypes. Further mechanical investigation revealed that VLT treatment elevated cAMP and p-CREB levels, reduced amyloid-β (Aβ) accumulation, promoted synaptic function, and ameliorated mitochondrial fragmentation, along with mtDNA homeostasis in the AD cell model. Moreover, under conditions of mtDNA depletion or Drp1 overexpression, VLT exerted neuroprotective effects and maintained mtDNA homeostasis via the cAMP-PKA-CREB signaling pathway. These results demonstrate that PDE4 inhibition by VLT represents a promising therapeutic strategy for AD and related neurodegenerative disorders. Full article

Marine fungi are pivotal components of coastal ecosystems, facilitating essential biogeochemical cycling and trophic dynamics. However, the complex mechanisms governing their spatiotemporal community patterns in tropical–subtropical coasts remain largely unexplored. In this study, we characterized marine fungal diversity across a comprehensive seasonal cycle (spring (March), summer (June), autumn (August), and winter (December)) at 21 representative sites along the Leizhou Peninsula, China. These sites were strategically selected to encompass a broad range of dissolved inorganic nitrogen (DIN) gradients. Fungal community composition was characterized via high-throughput sequencing of the internal transcribed spacer 2 (ITS2) region, followed by functional guild profiling using the FUNGuild database. A total of 8777 amplicon sequence variants (ASVs) were identified, encompassing a broad taxonomic breadth of 10 phyla and 358 genera. Ascomycota, Basidiomycota, and Chytridiomycota emerged as the predominant phyla across all samples. Our results revealed significant spatiotemporal heterogeneities: seasonal succession fundamentally reshaped community composition, with DIN exerting its most pronounced influence during the winter. Furthermore, fungal functional structures exhibited distinctive clustering across regions defined by DIN enrichment levels. Co-occurrence network analysis revealed a highly modular and robust architecture, characterized by predominantly positive interactions and dense inter-taxon connectivity. These findings underscore the synergistic influence of temporal dynamics and DIN enrichment in shaping marine fungal community assembly and functional compositions. Our study provides critical baseline insights into the ecological resilience of coastal mycobiota in the South China Sea. Full article

Marine-derived filamentous fungi are a rich source of structurally diverse and biologically active natural products. However, many biosynthetic gene clusters (BGCs) in fungi remain silent under standard conditions. In this study, we employed a metabolic shunting strategy to disrupt azaphilone biosynthesis in the marine-derived fungus Penicillium sclerotiorum E23Y-1A by deleting the pathway-specific regulator gene A00667. HPLC analysis revealed the emergence of new metabolite peaks in the mutant strain Δ667 compared to the wild type. Subsequent purification yielded seven compounds: the mutant produced two novel meroterpenoids sclerotilins A and B (1 and 2) along with the known steroids ergosta-5,7,22-trien-3β-ol (3) and cerevisterol (4), while the wild type yielded the known steroid (22E)-5α,8α-epidioxyergosta-6,22-dien-3β-ol (5) and two azaphilones geumsanol G (6) and 5-chloro-3-[(1E,3R,4R,5S)-3,4-dihydroxy-3,5-dimethyl-1-hepten-1-yl]-1,7,8,8a-tetrahydro-7,8-dihydroxy-7-methyl-(7R,8R,8aS)-6H-2-benzopyran-6-one (7). Bioactivity assays showed that compound 6 exhibited moderate antimicrobial activity against Staphylococcus aureus, and compound 3 displayed moderate cytotoxicity against five human cancer cell lines. These results demonstrate that A00667 is essential for azaphilone biosynthesis and that its disruption leads to the production of structurally distinct natural products, highlighting the potential of pathway engineering to redirect fungal metabolism to yield novel natural products. Full article