Objective: To develop a superoxide dismutase (SOD) fluorescent detection probe based on Phycoerythrin (PE) from Porphyridium cruentum for real-time monitoring of SOD activity, a core biomarker of oxidative stress, in a nonalcoholic fatty liver disease (NAFLD) model, and to explore the regulatory effect of astaxanthin. Methods: Phycoerythrin and SOD were covalently coupled using the heterobifunctional cross-linker N-Succinimidyl 3-(2-pyridyldithio) propionate (SPDP), and the probe concentration and incubation time were optimized. A NAFLD model was established in HepG2 cells induced by free fatty acids (FFAs). The fluorescence intensity of the probe was detected by flow cytometry, and the intervention effect of astaxanthin was evaluated by measuring triglyceride (TG)/total cholesterol (TC) contents and SOD activity. Results: The optimal conditions for the Phycoerythrin-SOD probe were determined. Astaxanthin at 20 μM significantly reduced FFA-induced TG (56.8%) and TC (63.6%) contents and restored SOD activity to 60% of that in the control group. Conclusion: The Phycoerythrin-SOD probe serves as an efficient tool for dynamic monitoring of SOD activity in NAFLD. Astaxanthin alleviates liver injury by multi-target regulation of lipid metabolism and antioxidant pathways.

Astaxanthin, a lipophilic carotenoid predominantly derived from microalgae such as Haematococcus pluvialis, exhibits potent anti-inflammatory and antioxidant properties. Despite previous reports of its anti-atherosclerotic effects, the underlying molecular mechanisms of astaxanthin remain unclear. This study aimed to elucidate the pharmacological mechanisms of astaxanthin in alleviating atherosclerosis progression via an integrated approach of network pharmacology, molecular docking, and in vitro experimental validation. Molecular docking revealed strong binding affinities between astaxanthin and core targets including TNF, IL-6, and PPARγ. In vitro experiments demonstrated that astaxanthin attenuated oxidative stress and suppressed the secretion of pro-inflammatory cytokines in oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs). Mechanistically, astaxanthin upregulated PPARγ expression and reduced the phosphorylation of p65 and IκBα, two key components of the NF-κB pathway. Co-treatment with the specific PPARγ antagonist GW9662 abrogated these protective effects, confirming a PPARγ-dependent regulatory mechanism. These findings indicate that astaxanthin exerts anti-atherosclerotic effects by modulating the PPARγ/NF-κB signaling axis, highlighting its potential as a functional food ingredient for cardiovascular protection.

The razor clam Sinonovacula constricta inhabits sulfide-rich intertidal sediments and exhibits remarkable tolerance to this toxicant, yet the role of its periostracum in sulfide adaptation remains poorly understood. In this study, we investigated the composition and structure of the periostracum proteins, and the response of the mantle to sulfide stress. Scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed that the periostracum is approximately 10 μm thick and contains 1.43 wt% sulfur, and proteomic analysis further confirmed the presence of organic sulfur (Cys/Met-rich proteins), suggesting its involvement in sulfur deposition. Using LC-MS/MS, we identified 77 high-confidence proteins from the periostracum, which were classified into six functional categories: enzymes, framework proteins, immune-related proteins, calcium ion-related proteins, other proteins, and proteins with unknown functions. Phylogenetic analyses of representative proteins revealed bivalve-specific evolutionary patterns, with several proteins exclusively present in Bivalvia, such as Unknown protein 2 and 7, which possess signal peptides and low-complexity domains. For the sulfide exposure experiment, razor clams were subjected to three Na2S concentrations (0, 10, and 100 μM). qPCR analysis showed that, compared with the control group, Chitin-binding protein 3 and Tyrosinase were significantly upregulated in the mantle, peaking in the 100 μM group at 48 h (5677.84-fold and 157.20-fold, respectively), whereas Collagen and Cadherin 3 were generally suppressed. This study represents one of the most comprehensive proteomic profiles of the razor clam periostracum and highlights the mantle's potential role in sulfide tolerance, offering insights for sulfur-tolerant aquaculture breeding and bioremediation applications.

Diabetic wound healing remains a clinical challenge due to impaired repair, often leading to complications such as infection and tissue necrosis. Here, we present a novel dual-drug-loaded hydrogel formulated using oxidized hyaluronic acid (OHA) and catechol-modified chitosan (CS-pC). This system is engineered to enhance the local bioavailability of polydatin (PD) and delay the release of tetramethylpyrazine (TMP), achieving superior release performance and synergistic effects compared to single-drug formulations; thus, this system enables synergistic modulation of the target inflammatory microenvironment and promotes angiogenesis, thereby facilitating effective diabetic wound healing. The hydrogel exhibited a porous structure (100-200 μm) and moderate swelling (119.67% ± 6.66% at 24 h). Approximately 80% of TMP and PD were sustainably released within 48-52 h, aligning with clinical dressing intervals. In diabetic mice, it accelerated wound closure to 98.01% within 14 d-20.63% higher than controls. Most notably, the hydrogel significantly promoted wound healing, as evidenced by: (1) upregulation of vascular endothelial growth factor (VEGF) andα-SMA expression (RT-qPCR: 3.2-fold for VEGF and 3.7-fold forα-SMA vs control); (2) enhanced cell migration (3.1-fold vs control) and angiogenesis (1.3-fold vs control); and (3) increased expression of CD31, TGF-β1 and collagen types I and III (IHC). These results demonstrate the therapeutic potential of the OHA/CS-pC/TMP/PD hydrogel for diabetic wound healing.

Type 2 diabetes mellitus (T2DM) is a multifactorial chronic disease, single-drug intervention may gradually become difficult to maintain good glycemic control, limiting its long-term use. Algal natural active substances, with their multi-target therapeutic effects and superior safety profile, are promising alternative candidates for the treatment of T2DM. C-Phycocyanin, an active substance derived from Spirulina, exhibits high antioxidant and anti-inflammatory properties, as well as favorable hypoglycemic effects, demonstrating unique therapeutic potential. Therefore, this study employed network pharmacology methods to screen and further validate potential target genes of C-phycocyanin in the treatment of T2DM. Network pharmacology analysis revealed that C-phycocyanin may improve insulin resistance and intervene in T2DM by regulating the MAPK signaling pathway. In vitro experiments further confirmed that C-phycocyanin can enhance the condition of insulin-resistant cells. Additionally, it significantly increased the phosphorylation levels of p38 and p44/42 proteins in the MAPK pathway and promoted the translocation of GLUT4 protein from the cytoplasm to the cell membrane. These findings provide a theoretical basis for the use of C-phycocyanin in treating T2DM, addressing the issues of efficacy and safety associated with current therapies, and offering a reference for the biomedical application of algal natural products.

Microplastic pollution poses a growing threat to aquatic ecosystems, yet its impacts on skeletal development in fish remain poorly understood. This study investigated the toxic effects of polystyrene microplastics (PS MPs) on skeletal development in zebrafish and compared the findings with recent reports in marine medaka to identify conserved and species-specific responses. In zebrafish, PS MPs accumulated primarily in the intestine, gill, and liver, leading to spinal deformities and cartilage matrix degradation. Exposure induced biphasic (14 vs. 28 days), time-dependent toxicity: short-term (14 days) stimulated osteogenic activity and locomotion, whereas prolonged exposure (28 days) suppressed cartilage differentiation and reduced swimming performance. Transcriptomic and qPCR analyses revealed dysregulation of key osteogenic and chondrogenic genes. To evaluate cross-species relevance, we also compare our zebrafish data with those from the marine medaka, which do not have osteocytes-a key structural difference that may influence toxic susceptibility. Consistent with marine medaka, both models show PS MP accumulation in gastrointestinal and respiratory tissues, biphasic behavioral changes, and disruption of conserved skeletogenic pathways (e.g., Runx2-Sp7 axis). However, differences in bone cell biology and in the manifestation of skeletal lesions highlight model-specific toxicological nuances. These findings underscore the dual-phase toxicity of PS MPs on fish skeletal systems and emphasize the value of multi-species comparisons for comprehensive ecological risk assessment of microplastics in aquatic environments.

Limpets, marine mollusks that feed on algae by scraping rocks, have evolved teeth renowned as among the strongest biological materials known. These teeth are iron-based biocomposites, primarily consisting of goethite nanorods embedded within a silica-rich matrix. A central mystery has been how limpets produce goethite-a mineral that typically requires extreme synthetic conditions-under ambient physiological settings. Here, we combined transcriptomics and functional assays to investigate the teeth of the limpet Cellana toreuma. RNA-seq in compartmented regions of teeth found differential gene expression for teeth formation involving intensive chitin metabolism and redox reaction. Through RNA interference, we demonstrated that a specific limpet-derived ferritin is essential for tooth iron accumulation and mineralization in vivo. We further identified and characterized this ferritin, showing its ability to bind Fe2+ and promote iron mineralization both in vitro and ex vivo. These findings provide direct evidence supporting the hypothesis that limpets form goethite through in situ oxidation of Fe2+. This work advances our understanding of limpet tooth microstructure and iron biomineralization mechanisms, offering valuable insights for the design of biomimetic wear-resistant materials under ambient conditions.

Alternative splicing (AS) is a fundamental posttranscriptional mechanism that amplifies proteomic diversity and enables adaptive responses across eukaryotes. Current AS detection methods rely heavily on reference genomes, limiting their applicability to non-model organisms. Existing reference-free approaches suffer from inaccurate splice site prediction and treat detection and classification as separate processes, resulting in cascading errors. We present IRCAS, an integrated end-to-end framework for reference-free AS analysis, comprising three modules: identification, rectification, and classification. IRCAS employs colored de Bruijn graphs for AS detection, an attention-based convolutional neural network for splice site rectification, and a hybrid graph neural network combining graph attention network and Transformer layers for classification. Evaluation across four species demonstrates substantial improvements: splice site accuracy increased to 92%-96% versus 50%-55% for existing methods, and end-to-end inference accuracy reached 83.4% on rice (fine-tuned) compared to 44.7% for the previous best method. IRCAS establishes a new benchmark for reference-free AS detection in non-model organisms.

With the growing global burden of cartilage degeneration in aging populations and the limitations of conventional surgical interventions, tissue-engineered hydrogels have emerged as a transformative strategy for functional cartilage regeneration. Here, we report an innovative bioinspired composite hydrogel fabricated through carbodiimide-mediated crosslinking of silk fibroin (SF) and hyaluronic acid (HA) using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC)/N-hydroxysuccinimide (NHS) in MES buffer. The engineered hydrogel exhibited an optimally interconnected porous architecture (pore size: 50-100 μm), tunable compressive modulus ( 86.51 KPa mimicking native cartilage), and swelling performance (570 ± 15%), addressing critical requirements for minimally invasive delivery and mechanical stability. Comprehensive in vitro characterization demonstrated exceptional cytocompatibility, with close to 100% hBMSC viability over 7 days. Most notably, the SF/HA hydrogel significantly promoted chondrogenic differentiation, as evidenced by: (1) 1.8 fold increased in progressive glycosaminoglycan (GAG) deposition (Alcian blue staining), (2) upregulation of SOX9, COL2, and AGG gene expression (RT-qPCR, 1.4, 0.4 and 1.3 fold vs. control), and (3) enhanced type II collagen synthesis (Western blot). These results demonstrate the potential of SF/HA hydrogel for cell-based cartilage repair and osteoarthritis therapy.

Type 2 diabetes mellitus (T2DM) is recognized as a multifactorial health disorder associated with various complications. This paper presents a bibliometric analysis of type 2 diabetes mellitus and natural active substances. Currently, the research field in this area is on an upward trajectory, with major research hotspots focusing on pathogenesis, pharmacological activities, the gut microbiota, and lipid metabolism. Algae-derived natural active substances, namely astaxanthin, extracellular polysaccharide from Porphyridium cruentum (EPS-P), and β-carotene, all exhibit high antioxidant properties and safety, along with favorable hypoglycemic effects. Therefore, their therapeutic intervention effects on type 2 diabetes mellitus were evaluated through in vitro experiments. Compared with the model group, astaxanthin, β-carotene, and Porphyridium cruentum polysaccharide (EPS-P) improved various indicators by at least 24.17%, 7.7%, and 6.7%, respectively. All three substances could, to a certain extent, enhance glucose consumption, glycogen content, and pyruvate activity, as well as improve and restore the condition of IR-HepG2 cells. The order of intervention efficacy was astaxanthin, followed by β-carotene, and then Porphyridium cruentum polysaccharide (EPS-P). These findings provide a scientific basis for the biomedical applications of algae-derived natural products.

Biopolymer hydrogels are revolutionizing biomedicine by synergizing ecological sustainability with dynamic biofunctionality, offering transformative solutions for tissue regeneration and precision therapeutics. Derived from polysaccharides (e.g., chitosan, hyaluronic acid), proteins (e.g., collagen, silk fibroin), and nucleic acids, these hydrogels recapitulate critical extracellular matrix (ECM) features through tunable viscoelasticity (elastic modulus: 1-100 kPa), multi-stimuli responsiveness (enzyme/pH/ROS), and spatiotemporal bioactivity. Recent innovations leverage their structure-function relationships: protein-polysaccharide interpenetrating networks (e.g., gelatin-oxidized alginate) enable stage-specific cytokine release (e.g., IL-10/TGF-β dual delivery) and interfacial tissue regeneration, while glycosaminoglycan-mimetic hydrogels direct stem cell differentiation via stiffness-mediated YAP/TAZ mechanotransduction. However, clinical translation faces critical barriers: reconciling injectability with load-bearing resilience, synchronizing degradation kinetics with tissue remodeling phases, and modulating immune-microenvironment crosstalk to balance biointegration and fibrosis (e.g., M1-to-M2 macrophage polarization). Emerging strategies address these through covalent-noncovalent dual crosslinking, zwitterionic immunomodulatory interfaces, and 4D-bioprinted architectures with anisotropic bioactivity. Challenges persist in preventing phase separation in hybrid systems and matching metabolic kinetics in vivo. Future directions demand molecular-scale engineering of dynamic networks, machine learning-guided multi-omics customization, and standardized validation frameworks. This review delineates a roadmap for transforming natural hydrogels from bioactive scaffolds to intelligent, clinically viable systems for active tissue repair and disease modulation.

Using network pharmacology, this study explores the anti-type 2 diabetes effect and its mechanism of all-trans astaxanthin derived from Haematococcus pluvialis, predicting the molecular targets and pathways of natural astaxanthin's anti-type 2 diabetes function. The results are validated through molecular docking and cellular experiments. A total of 83 astaxanthin core targets for type 2 diabetes are identified. Among them, the top three are AKT1, SRC, and MAPK, which are confirmed through molecular docking. In cellular experiments, natural astaxanthin significantly increases glucose consumption, glycogen content, and total superoxide dismutase (T-SOD) content in the model group, improving insulin resistance. Compared with the model group, astaxanthin up-regulates the expression of AKT1, SRC, and MAPK3 mRNA. This study is the first to combine network pharmacology with cellular experiments to confirm the effect of natural astaxanthin on improving type 2 diabetes, providing new avenues for the future treatment of type 2 diabetes and the development of astaxanthin-related products.

A three-step purification process combining powdered activated carbon adsorption, aqueous two-phase extraction, and dialysis-ultrafiltration was employed to isolate C-phycocyanin from Spirulina, followed by stability analysis. By comprehensively considering the effects of different treatment conditions for powdered activated carbon and the concentration of the extraction system in aqueous two-phase extraction on the purification of Cphycocyanin, determined the optimal process conditions: after treatment with powdered activated carbon adsorption, the crude C-phycocyanin extract underwent aqueous two-phase extraction and dialysisultrafiltration-centrifugation, the purity of C-phycocyanin reached 4.47, with a recovery rate of 41.77 %. Meanwhile, stability assessment was conducted, and the experimental results demonstrated that: C-phycocyanin solutions maintained a high pigment retention rate under conditions of 4 degrees C, pH 4-7, and away from light, the stability of dry powder was superior to that of the solution. The substitution of traditional salt precipitation with powdered activated carbon adsorption for crude C-phycocyanin extract treatment, coupled with aqueous twophase extraction and dialysis-ultrafiltration-centrifugation techniques, effectively addresses the challenges of cumbersome processes, low recovery rates, and time-consuming fine purification in C-phycocyanin production. This integrated approach significantly enhances purity while streamlining industrial-scale manufacturing, providing both scientific rationale and technical support for the development of high-value C-phycocyanin applications.

Bletilla striata polysaccharide (BSP) is effective at healing wounds and has important application value in the research and development of biomedical materials. In this study, BSP, chitosan, and sodium β-glycerophosphate were used to generate a complex hydrogel with a very small pore size of 10-30 μm without the use of cross-linking agents. By improving the cross-linking density, the mechanical property defects caused by excessive BSP dissolution were overcome without affecting its physiological activity. Moreover, the small molecule Danshen sodium (SDSS) was loaded into the three-dimensional network of this hydrogel to form a hydrogel drug carrier system. SDSS could be released in the long term, and the total amount released after 53 h was 96.26 ± 2.57%. The BSP hydrogel had good water absorption (169.47 ± 4.54%) and bonding properties. In vitro studies confirmed that it has a good antibacterial performance and biocompatibility and the ability to promote cell proliferation (>200%) and migration. Molecular experiments confirmed that the hydrogel promotes collagen expression. In vivo experiments using a mouse wound healing model confirmed that the hydrogel has an excellent ability to promote wound healing, particularly during the first 7 days of the wound. The wound healing rate of the hydrogel group was higher than that of the blank group by 27.61% (p < 0.05), and the effect of the hydrogel to promote wound healing was confirmed by wound tissue staining.

Arthrospira platensis intracellular polysaccharides have attracted significant attention due to their wide range of bioactive functions. The presence of residual pigments can negatively impact subsequent separation and purification processes, as well as the development and application of downstream products. In this study, a comparative analysis was conducted to evaluate the decolorization effects of various macroporous resins. The results showed that macroporous resin NKA-II had the highest decolorization rate and retention rate of polysaccharides. To optimize the decolorization process employing NKA-II, a systematic adjustment of various parameters was conducted, leading to the determination of optimal conditions: a sample speed of 3 BV/h (bed volume/h, BV/h), a sample concentration of 6.8 mg/mL, and a sample quantity of 1.3 BV. Under these optimized conditions, three parallel experiments were conducted, and the average comprehensive score was measured as 96.98 +/- 1.8 %. Subsequently, a comparison was made between the decolorization effects of NKA-II and those achieved through the use of hydrogen peroxide and activated carbon methods. The findings demonstrated that NKA-II outperformed both hydrogen peroxide and activated carbon in terms of decolorization efficiency. This highlights the superiority of NKA-II as a decolorization material for Arthrospira platensis intracellular polysaccharides. Overall, this study provides valuable insights into the optimization of the Arthrospira platensis intracellular polysaccharide decolorization process and the selection of appropriate decolorization materials, thereby contributing to further research and application of Arthrospira platensis intracellular polysaccharides in various fields.

Histone modifications, known as histone marks, are pivotal in regulating gene expression within cells. The vast array of potential combinations of histone marks presents a considerable challenge in decoding the regulatory mechanisms solely through biological experimental approaches. To overcome this challenge, we have developed a method called CatLearning. It utilizes a modified convolutional neural network architecture with a specialized adaptation Residual Network to quantitatively interpret histone marks and predict gene expression. This architecture integrates long-range histone information up to 500Kb and learns chromatin interaction features without 3D information. By using only one histone mark, CatLearning achieves a high level of accuracy. Furthermore, CatLearning predicts gene expression by simulating changes in histone modifications at enhancers and throughout the genome. These findings help comprehend the architecture of histone marks and develop diagnostic and therapeutic targets for diseases with epigenetic changes.

In this research, we unveil the medical potential of pearls by identifying a novel bioactive peptide within them for the first time. The peptide, termed KKCHFWPFPW, emerges as a pioneering angiotensin I-converting enzyme (ACE) inhibitor, originating from the pearl matrix of Pinctada fucata. Employing quadrupole time-of-flight mass spectrometry, this peptide was meticulously selected and pinpointed. With a molecular weight of 1417.5 Da and a theoretical isoelectric point of 9.31, its inhibitory potency was demonstrated through a half-maximal inhibitory concentration (IC50) of 4.17 μM, established via high-performance liquid chromatography. The inhibition of ACE by this peptide was found to be competitive, as revealed by Lineweaver–Burk plot analysis, where an increase in peptide concentration correlated with an enhanced rate of ACE inhibition. To delve into the interaction between KKCHFWPFPW and ACE, molecular docking simulations were conducted using the Maestro 2022-1 Glide software, shedding light on the inhibitory mechanism. This investigation suggests that peptides derived from the P. martensii pearl matrix hold promise as a novel source for antihypertensive agents.

Mollusk shells contain biominerals with remarkable mechanical properties enabled by a small fraction of embedded organic matrix proteins. However, the specific molecular functions of most shell proteins have remained elusive. Traditional genomics and functional studies are extremely laborious to identify key components. To address this, we developed an in-silico pipeline integrating protein structure modeling, molecular dynamics simulations, and machine learning to elucidate the critical ion protein interactions governing shell formation. Using the pearl oyster Pinctada fucata as a test case, our framework successfully recapitulated known protein functions and predicted roles of uncharacterized proteins to guide future experiments. Moreover, the pipeline’s modular design enables versatile applications for rapidly elucidating structure-function relationships in diverse biomineralization systems, complementing conventional wet-lab methods. Overall, this computational approach leverages automatic simulations and analytics to unlock molecular insights into shell protein ion dynamics, accelerating the discovery of key crystallization regulators for bioinspired materials design.