Search Results (830)

Large yellow croaker (Larimichthys crocea) is an economically important marine fish species in China, yet regional variation in its gut microbial community structure and functional characteristics remains insufficiently understood. This study aimed to characterize and compare the gut microbiota of farmed large yellow croaker across five representative aquaculture regions. Intestinal microbial communities were characterized using 16S rRNA gene sequencing, followed by analyses of microbial diversity, taxonomic composition, predicted bacterial phenotypes, co-occurrence networks, and environmental associations. The five cultured populations shared a broadly similar microbial community structure dominated by Proteobacteria, Bacteroidota, and Firmicutes, whereas the relative abundance of several dominant taxa varied among regions. Alpha-diversity differences were mainly associated with community evenness and dominance rather than estimated richness. Although regional samples partially overlapped in ordination analyses, the aquaculture region explained 41.4% of the variation in gut microbial composition, indicating significant region-associated differentiation. Predicted microbial characteristics were comparatively similar among cultured populations, despite variation in taxonomic composition, while microbial network organization also differed across regions. Environmental variables showed clearer associations with water microbiota than with gut microbiota, and local aquaculture water represented a detectable but limited potential source of intestinal microorganisms. Overall, farmed large yellow croaker maintained a shared gut microbial community structure but exhibited region-associated variation in community composition and predicted bacterial phenotypes. These findings provide a regional baseline for understanding gut microbial variation in farmed large yellow croaker under different aquaculture conditions. Full article

Metal corrosion and microbial contamination cause severe damage to marine facilities and result in immeasurable economic losses. Highly efficient and durable anti-corrosion and anti-fouling coatings represent the most effective solution strategy widely employed, whilst two-dimensional graphitic carbon nitride (g-C₃N₄), owing to its non-toxic and highly effective properties, is frequently utilized as a coating filler. Herein, this work innovatively engineered g-C₃N₄ into rod-like structures with layer-oriented alignment through a two-step simplified synthesis process, naturally achieving the self-assembly integration of ultrathin sheets. Subsequently, the special rod-like g-C₃N₄ (RCN) was blended with a polydimethylsiloxane (PDMS) matrix, ultimately yielding a multifunctional nanocomposite coating (RCN/PDMS) that combines mechanical reinforcement, long-term corrosion resistance, and microbial fouling protection. Notably, the compact lamellar structure within uniformly dispersed RCN particles in the polymer matrix effectively enhances the crosslinking density of the composite, significantly improving the coating’s adhesion and tensile strength (1.795 MPa). Furthermore, upon exposure to light, the modified RCN-2 releases substantial reactive oxygen species (ROS), exhibiting pronounced antibacterial activity (90.3% of E. coli and 95.1% of S. aureus) against surface-adhering microorganisms. Following a 60 d marine immersion simulation test, the impedance arc radius of the RCN-2/PDMS coating remained as high as 5.17 × 10⁹ Ω·cm², representing an improvement of nearly two orders of magnitude over pure PDMS coatings. This work expands the application of morphology-controlled g-C₃N₄-based fillers in marine anti-fouling and anticorrosion coatings. Full article

Although flaviviruses, including DENV, ZIKV and JEV, remain important causes of febrile, congenital, and neurological diseases, treatment options remain largely supportive, with limited availability of virus-specific antiviral therapies. Marine organisms and marine-derived microorganisms produce chemically distinct antiviral materials, including sulfated polysaccharides, terpenoids, alkaloids, peptides, cyclodepsipeptides, and polyketides. However, their activities range from preliminary extract-level inhibition to direct biochemical target validation, making mechanistic comparison difficult. This review critically evaluates marine-derived anti-flaviviral agents using two complementary dimensions, the infection stage implicated by experimental assays and the strength of evidence supporting that assignment. DENV evidence is dominated by sulfated algal macromolecules that interfere with adsorption or internalization, whereas ZIKV studies encompass lipophilic algal metabolites, fungal alkaloids, cyclodepsipeptides, and a few target-oriented candidates. Across the field, most reports remain stage-associated rather than target-validated. Cross-study potency comparisons are constrained by differences in virus strains, cell models, assay formats, and treatment schedules. JEV-specific evidence is particularly sparse. Based on the DENV and ZIKV evidence map, we propose concise priorities for JEV-oriented discovery: early compound-level dereplication, parallel cytotoxicity testing, orthogonal confirmation of productive infection, stage-resolved assays, and biochemical or genetic validation of conserved flaviviral targets. This evidence-based framework can help distinguish promising chemical candidate scaffolds from preliminary antiviral signals and guide mechanism-informed development of marine-derived natural products against flaviviruses. Full article

The search for antioxidant compounds from aquatic or marine environments to cope with the harmful effects of reactive oxygen species (ROS) is one of the major challenges in contemporary blue biotechnology. Among marine microorganisms, microalgae have emerged as promising candidates for the discovery and production of natural bioactive molecules with antioxidant properties. This review highlights the potential of microalgae and cyanobacteria as a sustainable source of antioxidant compounds and examines their growing relevance in biotechnology and pharmaceutical applications. A broad range of antioxidant metabolites produced by microalgae, including carotenoids, fatty acids, vitamins, polyphenols, and flavonoids, has also been discussed, with particular emphasis on their antioxidant mechanisms and bioactive properties. This review also integrates antioxidant mechanisms with the physiological and metabolic responses, underlying antioxidant production and sustainable strategies used to enhance their accumulation. Furthermore, microalgae offer the advantage of sustainable production systems, with the potential to enhance the biosynthesis and accumulation of valuable compounds through optimized cultivation strategies. Thus, different sustainable approaches aimed at increasing antioxidant compound production or reducing operational costs in microalgae cultivation are discussed to identify efficient and economically viable processes that maximize the biotechnological potential of these microorganisms for future industrial applications. Full article

The long-term accumulation of polyethylene terephthalate (PET) in marine environments may drive the evolution of microbial degradation capabilities, positioning the ocean as a valuable reservoir for discovering novel PET-degrading microorganisms. In this study, we isolated 305 marine-derived microorganisms with potential PET-degrading capability from samples collected from mangrove areas of Zhanjiang and the intertidal zones of Daya Bay, Shenzhen, China, using PET powder as a major carbon source. Subsequent evaluation of degradation performance via scanning electron microscopy and Fourier-transform infrared spectroscopy analysis identified 14 isolates capable of degrading PET film. These 14 strains belonged to 14 distinct species, none of which, to the best of our knowledge, has been previously documented as PET degraders. Among them, Microbacterium aurum SCSIO 85700 exhibited the most potent PET-degrading activity, achieving a weight loss of 2.1 mg (2.1%) and a 6.5% increase in relative crystallinity over 30 days. Genome analysis revealed the genetic basis underlying PET degradation and associated metabolic pathways in strain SCSIO 85700. Notably, genome mining and structural modeling identified two candidate polyester hydrolases, MA2267 and MA2443, possessing conserved His–Asp–Ser catalytic triads and exposed substrate-binding clefts resembling those of characterized PET-degrading enzymes, suggesting their potential involvement in PET depolymerization. Collectively, this study expands the recognized diversity of marine PET-degrading microorganisms and provides microbial resources for sustainable PET bioremediation. Full article

Photocatalytic antibacterial coatings have emerged as a promising antibiotic-free strategy for combating healthcare-associated infections, biofilm formation, marine biofouling, and environmental microbial contamination. Unlike conventional antimicrobial approaches, photocatalytic systems continuously generate reactive oxygen species (ROS) under light irradiation, enabling broad-spectrum antimicrobial activity while minimizing the risk of antimicrobial resistance. This review systematically summarizes the fundamental mechanisms underlying photocatalytic antibacterial activity, including photogenerated charge-carrier dynamics, ROS generation pathways, and microbial inactivation processes. We further highlight recent advances in photocatalyst design, spanning conventional semiconductor photocatalysts, heterojunction engineering, cocatalyst modification, and two-dimensional material-assisted strategies for enhanced photocatalytic performance. Crucially, particular emphasis is placed on coating architectures and interfacial regulation, including encompassing fabrication methodologies, coating–substrate adhesion, internal heterointerface design, and coating–microorganism interactions, which dictate long-term durability and antibacterial efficacy. Finally, we explore the diverse applications of these coatings in medical devices, environmental remediation, and marine antifouling, while identifying current bottlenecks and future research trajectories toward developing durable, highly efficient, and clinically translatable antimicrobial surface technologies. Full article

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease defined by persistent synovial inflammation, progressive cartilage and bone erosion, and extra-articular manifestations. Current treatments, such as disease-modifying anti-rheumatic drugs (DMARDs), glucocorticoids, and non-steroidal anti-inflammatory drugs (NSAIDs), control disease activity but are limited by toxicity, reduced response over time, and are expensive, demonstrating the need for safer and more effective adjuncts. The marine environment is a rich, largely untapped source of structurally diverse bioactive molecules that could be used to develop new therapeutics. This review compiles current evidence on anti-inflammatory and immunomodulatory compounds from marine organisms relevant to RA, including macroalgae, true marine microalgae, marine microorganisms (bacteria and fungi, including deep-sea taxa), sea cucumbers, sponges, mussels, corals, and jellyfish. Recurring mechanisms of action include inhibition of the NF-κB, MAPK, and JAK/STAT signalling cascades; suppression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2); reduced production of tumour necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6; and activation of the Nrf2 antioxidant response. Particular attention is given to functional lipids (eicosapentaenoic and docosahexaenoic acids, prostaglandin-like oxylipins) and pigments (astaxanthin, fucoxanthin, β-carotene) from marine microalgae and heterotrophic protists, which recent literature identifies as the most clinically advanced marine leads. To clarify translational status, compounds are grouped by their development stage (marketed nutraceutical, clinical trial, or preclinical) and summarised in a dedicated table. Some compounds, such as green-lipped mussel extract, microalgal omega-3 oils, and astaxanthin, have reached the stage of randomised controlled trials for arthritis. However, most other potential treatments are still in the early, preclinical phase. It is worth noting that ocean-derived compounds appear generally safe, but more thorough studies, especially in living organisms and in clinical settings, are needed to confirm their effectiveness for rheumatoid arthritis before any claims can be made about their therapeutic benefits. Full article

Natural bioactive compounds found in plants, agri-food by-products, microorganisms, marine sources, and other sustainable biological resources continue to drive scientific innovation due to their structural diversity and wide spectrum of biological activities, supporting advances in pharmaceuticals, nutraceuticals, functional foods, cosmetics, agriculture, and animal nutrition [...] Full article

Background/Objectives: Marine microorganism metabolites are structurally unique secondary metabolites possessing therapeutic potential. The current study aims to identify a novel ATPase regulator using a newly established bidirectional activity evaluation system to screen for microbial metabolites that inhibit the activities of Na⁺-K⁺-ATPase or Ca²⁺-Mg²⁺-ATPase. Methods: A total of 1258 marine microbial strains were isolated from sea mud in Zhoushan, Zhejiang. Results: The extract of strain ZSDH2536 exhibited Na⁺-K⁺ and Ca²⁺-Mg²⁺-ATPase inhibitory activity and was identified as Sirastachys pandanicola based on morphological and molecular phylogenetic analyses. The secondary metabolite was tentatively identified in the ZSDH2536 strain as a bisindole compound, and named Pandanicoline based on ¹H-NMR, ¹³C-NMR and high-resolution mass spectrometry analysis. The chemical formula of Pandanicoline is C₅₁H₆₈N₂O₁₀, with an isotopic mass of 868.4874 Da. The maximum inhibition rate of Pandanicoline on Na⁺-K⁺ and Ca²⁺-Mg²⁺-ATPase was 36.37% and 37.27%, respectively. Moreover, in silico analysis also showed the binding energy of Pandanicoline with Na⁺-K⁺-ATPase was −9.124 kcal/mol and with the Ca²⁺-Mg²⁺-ATPase complex was −10.47 kcal/mol. Conclusions: The strain ZSDH2536 represents a promising source of dual inhibitors targeting Na⁺-K⁺ and Ca²⁺-Mg²⁺-ATPase. Pandanicoline exhibits potential as a lead compound for regulating ion homeostasis, providing new opportunities for further investigation into its mechanism and therapeutic applications. Full article

Growing environmental concerns over petroleum-based plastics have increased interest in sustainable and biodegradable alternatives such as polyhydroxybutyrate (PHB). PHB is a naturally produced biopolymer synthesized by microorganisms and is widely recognized for its biodegradability, biocompatibility, renewability, and thermoplastic properties. Despite these advantages, PHB use remains limited by brittleness, high crystallinity, low thermal stability, a narrow processing window, and high production costs. This review discusses the production, properties, biodegradation behavior, and applications of PHB, with a focus on strategies to improve its performance. Modification approaches, including copolymerization, polymer blending, filler reinforcement, plasticization, and hybrid composite formulation, are critically reviewed to evaluate their effects on the thermal, mechanical, and processing behavior of PHB-based materials. The review also highlights recent developments in additive manufacturing, particularly fused deposition modeling/fused filament fabrication (FDM/FFF) for the extrusion of biodegradable PHB composite filaments. In addition, the biodegradation of PHB under various environmental conditions, including soil, compost, freshwater, marine, aerobic, and anaerobic environments, are discussed. Current challenges, research gaps, commercialization barriers, and future opportunities related to sustainable feedstocks, advanced composites, additive manufacturing, and circular economy integration are addressed. Overall, PHB shows strong potential as a sustainable alternative for packaging, biomedical, agricultural, and three-dimensional (3D) printing applications. Full article

Microbial communities associated with fish mucosal tissues play important roles in host health and environmental adaptation. However, the effects of contrasting aquaculture conditions on the microorganisms of the large yellow croaker (Larimichthys crocea, L. crocea) remain poorly understood. In this study, 16S rRNA gene sequencing was used to compare the gut and gill microbiota of L. crocea cultured in a marine system and a saline–alkaline system, together with the corresponding surrounding water samples. The results showed that both host tissue type and rearing environment significantly influenced microbial community structure. Water samples generally exhibited higher alpha diversity than host-associated samples, whereas the gut and gill communities were clearly separated from the surrounding water microbial community. The intestine showed stronger culture system differentiation than the gill, suggesting greater niche selectivity, while the gill retained a closer association with the rearing water. Across multiple taxonomic levels, microbial composition differed markedly among water, gut, and gill samples, and the divergence between the marine culture and saline–alkaline culture system became more pronounced at finer taxonomic resolution. Differentially enriched taxa further revealed clear tissue- and habitat-associated microbial patterns. In addition, several dominant taxa were significantly correlated with environmental variables, especially salinity and nutrient-related factors, indicating that physicochemical heterogeneity contributed substantially to microbial community assembly. Overall, this study shows that host mucosal niche and rearing environment are associated with distinct gut and gill microbiota patterns in L. crocea and provides preliminary ecological information for future microbiome-informed aquaculture management, functional validation of candidate taxa, and the development of land-based culture systems for marine fish. Full article

Drug discovery is a complex and resource-intensive process, with lead identification representing a major bottleneck due to high attrition rates. Natural products have long served as a valuable source of structurally diverse and biologically active compounds, offering advantages such as evolutionary optimization, target specificity, and unique chemical diversity. This review provides a comprehensive and mechanistic overview of natural products as lead compounds, emphasizing their chemical characteristics, biological relevance, sources, mechanisms of action, and integration into modern drug discovery pipelines. A narrative review was conducted using major scientific databases (PubMed, Scopus, Web of Science, and Google Scholar), covering literature from 2000 to 2026. Relevant studies were selected based on scientific rigor and contribution to key themes, including natural product diversity, discovery strategies, and technological advancements. Natural products exhibit superior structural complexity and occupy unique chemical space compared to synthetic compounds, enabling effective interaction with diverse biological targets and supporting polypharmacological activity. Key sources include plants, microorganisms, and marine organisms, which have yielded numerous clinically important drugs. Advances in analytical techniques, genome mining, metabolomics, synthetic biology, and artificial intelligence have significantly improved discovery and optimization processes. Despite challenges related to complexity and scalability, natural products remain indispensable in drug discovery, with emerging technologies enhancing their potential for addressing unmet medical needs. Full article

Halimeda-dominated habitats are ecologically significant tropical benthic ecosystems whose structural complexity supports diverse marine organisms, particularly associated microbes. However, the characteristics and ecological roles of these bacterial communities and their connectivity within Halimeda-dominated habitats remain poorly understood. This study examined microbial diversity and composition across four microenvironments of a Halimeda meadow, namely, ambient seawater, sediment, Halimeda thalli, and Holothuria atra feces, using the V3–V4 region of the 16S rRNA gene. A total of 44 phyla, 733 genera, and 827 species were identified, with Proteobacteria, Cyanobacteria, Bacteroidota, Desulfobacterota, and Actinobacteriota dominating across all samples. Microbial diversity and composition differed significantly among microenvironments, with sediment showing the highest species diversity and seawater showing the lowest. Halimeda thalli were dominated by Alphaproteobacteria, particularly Phycisphaerae and Parcubacteria, associated with nutrient cycling on macroalgal surfaces. Sediment was enriched with Desulfobacteria, Actinobacteria, and Chloroflexi. Seawater was characterized by Synechococcus CC9902, a primary producer in tropical waters. H. atra feces were dominated by Bacteroidia and Bdellovibrionota, representing a distinct bacterial community shaped by both gut-associated taxa and microorganisms derived from ingested sediments. Only 6.95% of genera were shared across all microenvironments, and feces and sediment shared the highest overlap (47.28%), suggesting that H. atra acts as a biogeochemical bridge that repackages benthic organic matter without fundamentally altering its microbial identity. The low overlap between Halimeda and seawater, as well as between seawater and both sediment and sea cucumber feces, suggests strong habitat-specific bacterial community assembly, with algal-associated bacterial communities being distinct from pelagic communities and seawater communities differing from benthic and fecal communities. 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

Microorganisms in sediments participate actively in biogeochemical cycling and are essential for maintaining the stability of marine ecosystems. To investigate the spatial impact of seaweed mariculture on sediment bacterial communities, three distinct zones were selected along the Zhanjiang coast, China: the Gracilaria salicornia aquaculture zone, a transition zone (adjacent to the aquaculture area), and a control zone (with no direct mariculture influence). In this study, 16S rRNA gene amplicon sequencing was employed to examine the composition, diversity, and potential functions of sediment bacterial communities across these three zones. The dominant microbial communities identified included Pseudomonadota, Thermodesulfobacteriota, Chloroflexota, and Acidobacteriota. Analyses of α-diversity, β-diversity, and molecular ecological network revealed that the bacterial community in the G. salicornia aquaculture zone exhibited significant differences in species composition, community structure, and interspecies interaction compared with those in the transition and control zones. Environmental factors such as pH, dissolved oxygen (DO) and nitrate (NO₃⁻) exerted significant influence on the bacterial community composition and structure. Predicted functional potential analyses indicated high abundances of pathways related to carbohydrate metabolism and amino acid metabolism. Overall, this study characterizes the spatial distribution patterns of microbial communities in a coastal seaweed mariculture ecosystem and provides important data to support further research on biogeochemical processes mediated by sediment bacteria and their response mechanisms to mariculture activities. Full article