This study investigated the alleviating effects of dietary lutein (LU) against high-fat diet (HFD)-induced hepatic lipid accumulation and fibrosis in black seabream (Acanthopagrus schlegelii). A 10-week feeding trial demonstrated that while LU did not alter growth performance, it significantly mitigated HFD-induced visceral adiposity. LU supplementation markedly lowered serum triglycerides (TG), cholesterol (CHO), and low-density lipoprotein cholesterol (LDL-C) levels compared to the HFD group. Histological analysis confirmed reduced hepatic lipid droplet accumulation, accompanied by decreased malondialdehyde (MDA) and reactive oxygen species (ROS) levels, alongside enhanced antioxidant enzyme activities. Transcriptomic profiling revealed that LU downregulated genes involved in cholesterol biosynthesis and fibrosis, with 3-hydroxy-3-methylglutaryl-CoA synthase 1 (hmgcs1) identified as a key target. Molecular docking and cellular thermal shift assay results supported an interaction between LU and Hmgcs1. In the established black seabream hepatocytes, LU suppressed oleic acid- (OA)-induced cholesterol biosynthesis and fibrotic gene expression, whereas hmgcs1 knockdown enhanced and hmgcs1 overexpression attenuated these protective effects. Collectively, dietary LU reduced HFD-induced hepatic lipid accumulation, oxidative stress, and fibrotic responses in black seabream, at least partly through downregulation of hmgcs1-associated cholesterol biosynthesis.
The teleost kidney is a vital hematopoietic and secondary lymphoid organ, yet the cellular coordination and regulatory circuits driving its response to systemic infection remain poorly understood. Here, we present a high-resolution single-cell transcriptomic atlas of the large yellow croaker (Larimichthys crocea) kidney during challenge with the necrotizing pathogen Pseudomonas plecoglossicida. Our analysis reveals a profound remodeling of the renal immune microenvironment, characterized by a dramatic expansion of the myeloid compartment and the emergence of an integrated cell death signature, comprising apoptosis, ferroptosis, and necroptosis that underlies the formation of characteristic visceral white nodules. Through trajectory and RNA velocity analyses, we demonstrate that bacterial infection triggers “emergency granulopoiesis”, driving the rapid differentiation of neutrophils, macrophages and mast cells into hyper-inflammatory states. Crucially, we identify a non-canonical, multi-lineage antimicrobial response in which phagocytes serve as the primary sources of the antimicrobial peptide hepcidin, with selected activated B-cell and regulatory T-cell populations displaying additional hepcidin-associated signatures. We further establish the IL-6-JAK2/STAT3 signaling pathway as the master regulatory axis orchestrating this systemic defense. Pharmacological inhibition of JAK2 abolished hepcidin induction, while exogenous IL-6 administration significantly enhanced host survival and bacterial clearance. These findings delineate the evolutionary conservation of cytokine-mediated antimicrobial regulation and provide a comprehensive model of organ-level immune coordination in early vertebrates.
Improving feed efficiency is crucial for the sustainable development of aquaculture. In this study, the feed conversion efficiency (FCE) of 240 largemouth bass (Micropterus salmoides) was individually assessed after 60-day independent culture. 14 individuals with the highest and the lowest FCE were defined as the High- and Low-FCE groups, respectively. The differences between the two groups in growth, feed utilization, whole genome, transcriptome, and metabolome were analyzed. The High-FCE group exhibited significantly better weight gain, specific growth rate, and protein efficiency ratio, while no significant difference was found in feeding rate, indicating that the growth advantage may originate from superior FCE. Genome-wide association analysis identified four significant SNPs and five candidate genes associated with FCE. Transcriptome profiling revealed that genes related to digestion, absorption, and immunity were significantly up-regulated, while genes related to energy-consuming biosynthesis and processing were significantly suppressed in the High-FCE group. Metabolome analysis indicated that the purine metabolites were accumulated and purine metabolic pathway was activated in the High-FCE group, suggesting optimized energy metabolism. The increase in adenine and glucuronic acid content in liver may be beneficial to the improvement of FCE. Furthermore, common differential genes and metabolites identified in the liver and brain were involved in regulating energy metabolism, fat metabolism, immunity, and signal transduction, indicating the existence of a liver–brain synergistic regulatory network for FCE. In conclusion, high feed efficiency in largemouth bass resulted from the synergistic integration of enhanced nutrient digestion and absorption, optimized energy metabolism, improved immune capacity, and efficient signal transduction.
Understanding the mechanisms of salinity adaptation is crucial for developing resilient aquaculture practices, especially under fluctuating or low-salinity conditions. This study integrated growth performance, physiological metabolism, transcriptomics, proteomics, and in vivo knockdown to investigate low-salinity adaptation in mud crabs under two salinity conditions (25‰ and 6‰) and three dietary lipid sources (fish oil, FO; krill oil, KO; safflower oil, SO). The results indicate that low-salinity adaptation is driven by energy-dependent osmoregulatory reprogramming through the coupling of lipid-energy metabolism and ion–water regulation. Low-salinity-induced structural and functional remodeling of osmoregulatory organs, promoted triglyceride mobilization by suppressing acc and fas while activating cpt1 and hsl, and enhanced mitochondrial β-oxidation and respiratory energy production to support osmoregulation. Under low-salinity conditions, crabs fed the FO and KO diet showed stronger lipid catabolism, mitochondrial activity, and osmoregulatory responses than those fed the SO diet. Multi-omics analysis further suggested that FO mainly supported membrane repair, and KO enhanced antioxidant and anti-apoptotic capacity, whereas SO caused broad inhibition of basic cellular processes. The proximal tubule bicarbonate reclamation pathway and aquaporins emerged as central components of the adaptive response. Two aquaporin genes, AQP1 and AQP7, were cloned and characterized for the first time in mud crab. Subcellular localization in HEK293T cells showed hypoosmotic stimulation-induced redistribution of AQP1 and AQP7 toward the plasma membrane, indicating their potential membrane relocalization under osmotic challenge. Functional knockdown of AQP1 or AQP7 under low salinity disrupted osmoregulation and impaired lipid catabolism and mitochondrial energy production, as reflected by reduced CPT1 and respiratory chain gene expression. These findings suggest that AQP1 and AQP7 contribute to the coordination of osmotic regulation, lipid metabolism, and energy homeostasis, providing new insights into nutritional regulation of low-salinity adaptation in mud crab.
Improving the stability and intestinal absorption of antioxidants is a prerequisite for exerting their functional activities. Herein, astaxanthin (AXT)-loaded Lactobacillus rhamnosus GG-derived extracellular vesicles (EVs) (AXT@EVs) were prepared using ultracentrifugation combined with four loading strategies, including ultrasonication, co-incubation, freeze–thaw cycles, and extrusion. Among these methods, AXT@EVs prepared by ultrasonication exhibited the highest encapsulation efficiency. When the mass ratio of AXT to EVs was 1:10, the encapsulation efficiency reached approximately 72.93
Plant diseases caused by Lasiodiplodia theobromae have expanded in both geographic range and host diversity, posing an increasing threat to agriculture and forestry. Owing to the limited understanding of these diseases and the lack of effective control strategies, the development of novel agricultural fungicides is urgently needed. In this study, eight new naphthoquinone derivatives (1–8), designated fusariumquinones A–H, respectively; two new enoic acids (9 and 10), designated fusariumacids A and B, respectively; and one new natural product (11), designated fusariumacid C, were isolated from the marine-derived fungus Fusarium solani XLGM24, obtained from Acanthus ebracteatus. Their structures and absolute configurations were elucidated using 1D and 2D NMR spectroscopy, HR-ESI-MS, the modified Mosher method, and time-dependent density functional theory electronic circular dichroism calculations. Notably, compound 2 exhibited significant antifungal activity against L. theobromae, with an EC50 value of 19.29 μg/mL, surpassing that of the positive control azoxystrobin (28.98 μg/mL). Mechanistic studies revealed that compound 2 disrupted the permeability and integrity of the cell membrane of L. theobromae, resulting in substantial morphological damage. Physiological assays demonstrated that compound 2 increased malondialdehyde levels, reduced soluble protein content, inhibited the activities of antioxidant enzymes, exacerbated oxidative stress, and disrupted the physiological metabolism of L. theobromae mycelia. In addition, compound 2 enhanced the innate defense responses of mango fruits, thereby increasing their resistance to L. theobromae. These findings identify compound 2 as a promising lead candidate for the development of novel fungicides.
Arginine kinase (AK) is a major allergen found in Oratosquilla oratoria. However, the information about the formation of its conformational epitopes is limited. In this study, the three-dimensional structures of O. oratoria AK and eight conformational mimotopes were predicted using bioinformatic methods. All key amino acids of the predicted conformational mimotopes were individually deleted using site-directed mutagenesis, and changes in IgE-binding capacity were measured. Relative to native AK, the IgE-binding capacities of the three mutants were significantly reduced, confirming the presence of three conformational epitopes: O-AK-1, O-AK-2, and O-AK-3. Structural analyses indicated that the deletion of key residues induced subtle changes in secondary structure, surface hydrophobicity, and electrostatic potential, which may be responsible for localized structural distortions in the epitope regions. Furthermore, a comparison across shellfish species found that O-AK-1 and O-AK-2 were conserved within crustacean species and that O-AK-3 was conserved across crustaceans and mollusks. Overall, three conformational IgE epitopes were identified, and the deletion of key amino acids reduced IgE-binding capacity owing to localized structural alterations. The conserved epitopes suggest a potential molecular basis for cross-reactivity among shellfish. Collectively, these findings provide a foundation for epitope-based allergen-specific therapeutic strategies.
Horizontal gene transfer (HGT) is hypothesized to be a major force driving evolutionary change. Recent research has identified HGT events in individual algal genomes, but comprehensive investigations of the patterns and functional diversity of HGT across the Phycophyta remain lacking. Here, we systematically detected 6418 HGT events in 169 algal genomes belonging to nine major plastid-containing taxa: Chlorophyta, Bacillariophyta, Ochrophyta, Rhodophyta, Alveolata, Haptophyta, Streptophyta, Cryptophyceae, and Prasinodermophyta. Over 90
In the mantle cavity of the heterobranch snail Physella acuta, collected from a lake in Slovakia (Central Europe), we identified the peritrich ciliate Trichodina chlorophora harboring endosymbiotic green algae. To elucidate the evolutionary origins of this tripartite consortium, we determined the phylogenetic affiliations of all three partners and conducted a detailed morpho-molecular characterization of the ciliate, a central component of this hyper-symbiotic system. The European population of T. chlorophora closely matched North American populations previously described from physinine snails. The diagnostic features of T. chlorophora include: body diameter of 41u201383 u03BCm after dry silver nitrate impregnation; denticle ring 23u201339 u03BCm wide, with 23u201330 denticles and 9u201311 radial pins per denticle; denticles 5.7u20137.8 u03BCm long; adoral ciliary spiral performing ~ 1.13 turns (390u00B0u2013409u00B0) around peristomial disc; and a horseshoe-shaped macronucleus. Phylogenetic analyses revealed that: (1) the host snails are closely related to North American conspecifics, reflecting the human-mediated introduction of this invasive gastropod to Europe; (2) trichodinids colonized aquatic snails multiple times independently from poikilothermic vertebrate hosts, with T. chlorophora clustering with freshwater congeners from frogs, snails, and planarians; and (3) the endosymbiotic green algae comprise two species: Chlorella sp., closely related to endosymbionts of heliozoans and cnidarians, and Jaagichlorella geometrica, which clusters with epiphytic congeners. While the algae exhibit low host specificity, snail-dwelling Trichodina species show high phylogenetic host specificity. The parallel emergence of green algae-bearing trichodinids in physinine and planorbid snails suggests co-evolutionary processes that independently gave rise to interdependent associations among aquatic snails, ciliates, and zoochlorellae.
Global warming may drive adaptive evolution by influencing natural selection and utilizing temperature-related phenotypic plasticity. However, predicting the evolutionary patterns of phenotypic plasticity under climate change remains a challenge, underscoring the need to elaborate on the underlying genetic and molecular mechanisms. In this study, we focus on the expression plasticity divergence of heat shock protein 90 (Hsp90), which is temperature responsive and exhibits a strong selective sweep in the upstream noncoding region of two allopatric congeneric oyster species: cold-adapted Crassostrea gigas and warm-adapted Crassostrea angulata. Functional characterization confirmed Hsp90 expression as an ideal proxy for thermotolerance. The evolutionary divergence in constitutive and plastic expression patterns represents adaptation to the mean and variance in habitat temperature, respectively. By combining forward and reverse genetic approaches, four causative loci with G + G u00D7 E effects were identified in the Hsp90 promoter regions of C. gigas and C. angulata, indicating cis-variations. Moreover, the g.-2291G allele of the causative locus in C. angulata is specifically bound to by the positive transcription factor purine-rich element binding protein B (PURB), explaining the constitutive expression of Hsp90. Meanwhile, the response of PURB to thermal stress determines the magnitude of plastic Hsp90 expression in C. angulata. This integrative study revealed that cis-variations interact with trans-variations and underlie the G u00D7 E effect under environmental changes, thereby mediating the divergence in plastic gene expression. Furthermore, we established a paradigm for studying genetic variants and their G u00D7 E impacts at a finer resolution, i.e., single-nucleotide level, in nonmodel organisms. The findings may deepen our understanding of the significant role of phenotypic plasticity in modulating adaptive responses and promote predictions of adaptive potential in marine organisms under climate change.
Fish are prone to lipid deposition when fed a high carbohydrate diet (HCD), making them suitable models for investigating the potential mechanisms of HCD-induced fat accumulation. In the present study, Nile tilapia and zebrafish liver cell lines (ZFL) were used to investigate the potential mechanisms of high carbohydrate-induced fat deposition. Our results found that HCD induces hepatic lipid accumulation and insulin resistance in fish. HCD activates the hexosamine biosynthetic pathway (HBP), increasing UDP-GlcNAc levels and upregulating hepatic OGT expression and O-GlcNAcylation. Interestingly, supplementing with the O-GlcNAcylation substrate glucosamine and inhibiting O-GlcNAcase (OGA) both promote triglyceride accumulation in ZFL. In contrast, inhibiting O-GlcNAc transferase (OGT) can block the triglyceride accumulation induced by glucose. Our further study results indicate that high carbohydrate enhances the protein stability of sterol regulatory element-binding protein cleavage-activating protein (SCAP) by increasing its O-GlcNAcylation level. This, in turn, promotes the formation of the SCAP-sterol regulatory element-binding protein 1 (SREBP1) complex, as well as the cleavage and nuclear translocation of SREBP1. Consequently, these processes regulate lipid anabolism and induce hepatic lipid accumulation. This finding provides a plausible explanation for the sustained activation of SREBP1 in the context of insulin resistance induced by HCD.
Functional additives play a significant role in improving health problems caused by high-fat diet (HFD) in farmed fish species. This study aimed to evaluate the effects of trans-cinnamaldehyde (TCA) on liver and gut health of HFD-feeding zebrafish. The results showed that triglyceride (TAG), serum alanine aminotransferase (ALT) and aspartic aminotransferase (AST) concentrations were significantly reduced in the TCA50 group. Liver malondialdehyde (MDA) content was significantly reduced, whereas higher activities of glutathione peroxidase (GPX), superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T-AOC) were recorded in the TCA50 group. Besides, TCA promoted the expression of proteins related to the antioxidant stk11/ampkα/nrf2 pathway. Serum lipopolysaccharides (LPS) content and expression of pro-inflammatory genes were notably reduced in the TCA groups, and the TCA50 group improved the intestinal villi and goblet cells in the midgut and hindgut. Zebrafish survival rate was increased in TCA groups after challenged with Aeromonas veronii Hm091 and Aeromonas hydrophila NJ-1. The relative abundances of Fusobacteriota and Cetobacterium were elevated in the TCA50 group. The gut microbiota altered by TCA50 group indirectly improved the antioxidant capacity of germ-free (GF) zebrafish, through the antioxidant gsk3β/nrf2 pathway, with Cetobacterium somerae potentially acting as the primary effector bacterium in enhancing the antioxidant capacity of the fish. Feeding of 50 mg/kg TCA directly to GF zebrafish activated the stk11/ampkα/nrf2 pathway and enhanced the expression of antioxidant enzymes. In conclusion, dietary supplementation with 50 mg/kg TCA alleviated HFD-induced oxidative stress in zebrafish via direct activation of stk11/ampkα/nrf2 and gut microbiota-mediated activation of gsk3β/nrf2 pathways.
This study evaluated whether dietary creatine supplementation could alleviate growth retardation and flesh quality deterioration induced by high soybean oil (SO) diets in juvenile large yellow croaker (Larimichthys crocea). Five experimental diets were formulated using fish oil (FO), soybean oil (SO) and SO supplemented with 5, 10, and 20 g/kg creatine. After a 70-day feeding trial, fish fed the SO diet exhibited impaired growth performance, reduced muscle springiness, gumminess and water-holding capacity, and increased lipid deposition compared with the FO group. Notably, supplementation with 10 g/kg creatine significantly improved growth performance and markedly enhanced muscle hardness, springiness and water-holding capacity. These improvements were accompanied by increased myofiber density, reduced myofiber diameter, and a reduction in muscle triglyceride and cholesterol contents. Mechanistically, creatine supplementation inhibited SO diet-induced expression of myostatin (mstn), and increased expression of myogenesis-related factors (e.g., myod, myog, mef2c). Meanwhile, creatine supplementation downregulated lipogenesis-related genes while promoting lipid transport and fatty acid oxidation in muscle. These findings demonstrate that creatine effectively reshapes muscle development and lipid deposition patterns under SO-based feeding conditions, thereby improving growth performance and flesh quality in large yellow croaker.
Hybrid culter (Derived from lineage of Megalobrama amblycephala ♀ × Culter alburnus ♂; denoted as BTBT) is a superior cost-effective aquaculture germplasm with pronounced high-fat diet (HFD) tolerance. A 12-week feeding trial using five crude lipid gradients (3–15
Assessing food web dynamics is crucial for understanding the impact of climate change on Antarctic coastal ecosystems. We assessed the spatial heterogeneity of biodiversity and food web structures in Marian Cove, Antarctica, an area that is experiencing rapid ecological change, by analyzing multiple genetic loci from environmental DNA. Biodiversity in Marian Cove varied distinctly between the inner and outer coves, which correlated with the physicochemical properties of seawater influenced by glacial retreat. The size composition of primary producers, represented by diatoms in the outer cove and nano- or pico-phytoplankton in the inner cove, was identified as the core taxa in each food web. The food web in the inner cove was primarily driven by bottom-up regulation, with smaller phytoplankton size classes responding to environmental fluctuations, in contrast to the outer cove, which was primarily influenced by oceanic water with large diatoms that enhanced the food web structure stability. Our study enhances the understanding of food web dynamics in Antarctic coastal ecosystems in response to glacial retreat driven by climate change.
Microbial infections and the emergence of antibiotic resistance have become major global health concerns. The continuous search for structurally unique and pharmacologically active compounds derived from natural sources is crucial for the development of new antimicrobial agents. Marine-derived fungi represent a prolific source of chemically diverse natural products with great potential for the discovery of novel antibiotics. In this study, four new naphtho-pyrone dimers, curvupyrones A–D (1–4), six new xanthone dimer derivatives, curvupyrones E–J (5–10), and three known analogs (11–13) were isolated from the mangrove endophytic fungus Curvularia sp. QQYZ-4 under bioactivity-directed guidance and heteronuclear single quantum coherence (HSQC)-based DeepSAT. The planar structures of new compounds 1–10 were elucidated using high-resolution electrospray ionization mass spectrometry (HRESIMS) and 1D/2D NMR. Compounds 1–10 possess complex axial chirality and stereochemical configurations, and their absolute configurations were determined by comprehensive analysis combining energy barrier calculations, nuclear Overhauser effect spectroscopy (NOESY) analysis, Cotton effects, DP4⁺ analysis, and ECD calculations. Notably, 9–12 exhibit significant antimicrobial activity against Escherichia coli (E. coli), Salmonella typhimurium (S. typhimurium), Methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans (C. albicans), with MICs ranging from 2 to 8 μg/mL. Furthermore, scanning electron microscopy (SEM) revealed that compound 9 disrupts the structural integrity of E. coli and S. typhimurium. This study not only enriches the chemical diversity of naphtho-pyrone dimers and xanthone dimer derivatives but also provides a chemical basis for research and development targeting antimicrobial agents.
A systematic chemical investigation of the deep-sea-derived fungus Penicillium limosum ZEN48 resulted in the isolation of four new indole-diketopiperazine alkaloids, limopiperazines A–D (1–4), alongside 16 known analogues (5–20). The structures of the new compounds were determined through comprehensive spectroscopic analysis, quantum chemical calculations, X-ray crystallography, and biogenetic considerations. Limopiperazine C (3) potently inhibited osteoclast differentiation and disrupted actin ring formation. Integrated RNA sequencing, RT-qPCR and molecular docking revealed that limopiperazine C exerts the anti-osteoclastogenic effect by modulating the ferroptosis signaling pathway via targeting heme oxygenase-1 (Hmox-1), positioning it as a promising lead compound for developing anti-osteoporotic agents.
Latency-reversing agents (LRAs) are molecular entities designed to reactivate latent HIV proviruses for subsequent elimination by the immune system or antiviral therapies. Interestingly, in our systematic exploration of fungal pigment diversity, the marine-derived strain Microsphaeropsis arundinis P1B was identified as a prolific azaphilone producer through phenotype-guided screening, suggesting that such fungal compounds may serve as novel LRAs with enhanced efficacy. Further investigation of its solid-fermented rice medium yielded 18 unprecedented sclerotiorin-type azaphilones (microsphazaphilones H–Y, 1–18). Extensive spectroscopic analysis, modified Mosher’s method, TDDFT-ECD calculation, and X-ray diffraction were used to determine their structures including absolute configurations. These compounds exhibit remarkable structural novelty, manifested by features such as unprecedented di- to tetra-carbon truncations in side chains, diverse oxidative modifications (e.g., epoxidation, hydroxylation), or unique stereochemical configurations in the pyranoquinone core. Biological screening identified microsphazaphilone W (16) as a potent HIV LRA. Mechanistic studies confirmed 16 reactivated latent HIV through NF-κB pathway activation, positioning it as a promising candidate for “shock and kill” strategies.
Determining the appropriate dietary arginine (Arg) requirement and elucidating its roles in growth performance and immune defense are essential for the mud crab (Scylla paramamosain). In this study, we evaluated the effects of dietary Arg supplementation on crab growth and resistance to Vibrio. Feeding trials established 1.45
