Marine Biotechnology最新文献

Paralytic shellfish toxins (PSTs) are widely distributed neurotoxins that accumulate and transform in bivalves, but the metabolic mechanisms after exposure of Azumapecten farreri (A. farreri) to PSTs remain unknown. To verify the phase I (cytochrome P450, CYP450)-II (glutathione S-transferase, GST)-III (ABC transport) metabolic genes for PSTs, we used RNA interference (RNAi) to silence target genes (CYP46A1, GSTM1, and ABCF2), measured PSTs content, and performed single nucleotide polymorphism (SNP) screening. Injection of small interfering RNA (siRNA) fragments into the scallop adductor muscle silenced target genes in multiple tissues. The three most effective fragments were selected. Secondary injection of screening fragments prolonged the silencing duration, with a silencing efficiency of 12.0%–100%. Silencing increased PSTs accumulation. Notably, with CYP46A1 silencing, the PSTs accumulation (1016 µg STXeq/kg) reached 3.85 times that of the control group. This silencing also delayed the conversion of highly toxic components (GTX1–4) to components with low toxicity (C1–2), thereby prolonging the PSTs metabolic process. SNP analyses indicated that PSTs exposure increased homozygous mutations in CYP49A1 (511908 site), this site is potentially involved in PSTs metabolism. In summary, this study optimized an RNAi method and confirmed the existence of a three-phase metabolic mechanism in scallops. CYP450 was found to be the main mode of PSTs metabolism. This study provides data regarding PSTs metabolic genes and loci in bivalves, as well as valuable molecular markers for anti-toxin breeding in shellfish.

Urechis unicinctus is an economically important aquaculture species and an emerging model for developmental and evolutionary research; however, progress in functional genetic studies in this species has remained limited by the absence of effective genome editing approaches. Here, we establish a CRISPR/Cas9-mediated genome editing platform in U. unicinctus based on an optimized microinjection procedure. Targeting the cilia-associated gene Caveolin-1, Cas9/sgRNA ribonucleoprotein complexes were delivered into oocytes, generating mosaic G0 larvae harboring insertion–deletion mutations, as confirmed by ICE analysis and cloning-based Sanger sequencing with mutation detection rates of 68.51% and 64.86%, respectively. Ciliary defects were frequently observed in edited larvae, including shortening of the circumoral ciliary ring and reduction of apical ciliary tufts, accompanied by impaired swimming performance. Whole-mount in situ hybridization further revealed altered spatial expression patterns of Caveolin-1 in edited embryos, with 78% of individuals showing detectable changes in expression patterns. To independently assess the robustness of the platform, the conserved cytoskeletal gene α-tubulin was additionally targeted, resulting in successful mutagenesis and associated ciliary abnormalities. Together, these findings establish the first CRISPR/Cas9 genome editing workflow for U. unicinctus, providing a technical framework for functional genomics in echiurans and facilitating future studies of developmental mechanisms and molecular breeding in this species.

Tetrodotoxin (TTX), commonly known as pufferfish toxin, is widely distributed among marine organisms. In the past decade, TTX has been detected in edible bivalves along coasts worldwide, raising concerns about unexpected food poisoning. Recent research suggests that planktonic larvae of the TTX-bearing flatworm Planocera multitentaculata are involved in the toxification of bivalves. However, some uncertainties remain: although these flatworms contain large amounts of 5,6,11-trideoxytetrodotoxin (TDT), TDT is generally not detected in bivalves, even when TTX is present. The aim of this study was to characterize the accumulation and excretion of TTX and TDT in the mussel Mytilus galloprovincialis after ingestion of toxic P. multitentaculata larvae and to determine whether differences in their excretion could explain the rarity of TDT in naturally contaminated bivalves. LC–MS/MS analysis revealed that the toxified mussels accumulated both TTX and TDT in the midgut gland. However, the concentrations of both compounds decreased over time, with TDT showing a faster decline than TTX. These findings provide the first evidence for the accumulation and excretion of TDT in bivalves and suggest that its faster elimination contributes to its rare detection in naturally contaminated specimens. The results also indicate that detection of TDT in wild bivalves may reflect relatively recent ingestion of TTX-bearing organisms, providing new insights into TTX analog dynamics and contributing to seafood safety monitoring.

Ulva prolifera (U. prolifera), a large green alga widely distributed along coastlines worldwide, can trigger marine ecological issues such as “green tides” when over-proliferating. Nevertheless, it is abundant in various nutrients and bioactive compounds, making the utilization of this alga an urgent task. In this study, an antioxidant peptide fraction (UCP‑1) was isolated and purified from U. prolifera. LC‑MS/MS analysis indicated that the peptide composition and molecular weight distribution of UCP‑1 possess typical characteristics of antioxidant peptides. In vitro experiments demonstrated that UCP‑1 at a concentration of 1 mg mL⁻¹ exhibited a DPPH radical scavenging capacity of 38.86 ± 2.7%, indicating antioxidant activity. In human immortalized keratinocytes (HaCaT) and zebrafish models, UCP-1 pretreatment reduced hydrogen peroxide (H₂O₂)-induced reactive oxygen species (ROS) and malondialdehyde (MDA) levels while increasing superoxide dismutase (SOD) activity. In zebrafish, UCP-1 also enhanced catalase (CAT) and glutathione peroxidase (GSH-Px) activities. In addition, incorporation of UCP‑1 into lotions and creams in skin trials improved skin hydration and elasticity and reduced erythema. Overall, the peptide UCP‑1 derived from U. prolifera exerts antioxidant activity and may serve as a natural antioxidant ingredient in cosmetic formulations, thereby providing an alternative approach for the high-value utilization of U. prolifera resources.

Bisphenol S (BPS) is an emerging environmental contaminant that can disrupt oxidative and immune homeostasis in aquatic organisms, whereas myo-inositol (MI) is a water-soluble nutrient involved in growth and cellular signaling. This study evaluated growth, hepatopancreatic biochemical indices, and stress-related gene transcription in crayfish fed 0 or 1000 mg/kg supplemental MI and chronically exposed to 0–10 µg/L BPS for 6 weeks. Compared with the control group, the BPS group had significantly lower weight gain rate (WGR), specific growth rate (SGR), molting frequency, antioxidant enzyme activities (SOD, CAT, and POD), and immune enzyme activities (ACP, AKP, PO, and LZM), together with higher MDA content (P < 0.05). Compared with the BPS group, the MI + BPS group had significantly higher WGR, SGR, molting frequency, SOD, POD, ACP, and PO activities (P < 0.05). The MI + BPS group also showed higher nrf2 and hmc mRNA levels and lower keap1, bip, ire1, casp3, cytc, jnk, il-6, tnf-α, and nf-κb mRNA levels than the BPS group (P < 0.05). WGR, SGR, molting frequency, and hmc mRNA abundance in the MI + BPS group did not differ significantly from the control group (P > 0.05), the remaining endpoints showed indicator-specific responses. These findings indicate that dietary MI supplementation was associated with improved growth and selected antioxidant and immune indices, as well as altered transcription of genes related to oxidative, endoplasmic-reticulum-stress, inflammatory, and apoptosis-associated responses under BPS exposure. Pathway activation, tissue injury, and apoptosis were not directly assessed.

Efficient transgene expression following nucleic acid transfection remains difficult in many fish cell lines, particularly those derived from marine species. Although extracellular delivery systems have been extensively optimized, intracellular factors that limit the expression of delivered nucleic acids remain poorly understood in teleosts. In mammals, TRIM25 (tripartite motif-containing protein 25) participates in cytoplasmic exogenous RNA surveillance. Here, we examined whether its teleost homolog contributes to the low reporter expression observed after transfection. Transient siRNA-mediated knockdown of trim25 increased the percentage of eGFP-positive cells following Cap1-m¹Ψ-eGFP mRNA transfection from 19.27% to 74.63% in zebrafish embryonic fibroblast cell line (PAC2) and from 10.41% to 36.15% in Chinese tongue sole testis cell line (CST). Reporter expression following pEGFP-N1 plasmid transfection was also increased, although to a lesser extent. In this study, transfection efficiency was operationally defined as the percentage of eGFP-positive cells among total nuclei and did not directly measure nucleic acid uptake. These findings suggest that transient trim25 knockdown may alleviate intracellular restriction of exogenous reporter expression in PAC2 and CST cells and may provide an affordable approach for improving molecular manipulation in selected fish cell systems.

This study aimed to investigate the effects of different diets on the growth performance, digestive capacity, and intestinal health of Megalobrama pellegrini larvae. A 30-day feeding trial was conducted using ten-day-old larvae, which were divided into five dietary groups: microdiet (MD), Tubifex tubifex (Tub), Artemia salina (Art), MD + Tub and MD + Art. Results showed that the Tub group achieved significantly higher final body weight, total length, and survival rate (86.00%) compared to all other dietary groups (p < 0.05). It exhibited the highest activities of trypsin, lipase, and alkaline phosphatase, alongside significantly superior intestinal villus height, width, and muscular thickness compared to other groups (p < 0.05). Gut microbiota analysis not only revealed a higher abundance of beneficial bacterial phyla (e.g., Verrucomicrobia, Bacteroidetes) in the Tub group, but also showed enhanced activity in functional pathways related to lipid metabolism, terpenoid and polyketide synthesis. A total of 1,825 differentially expressed genes (DEGs) and 330 differential metabolites (DMs) were identified between the MD and Tub groups. Transcriptomic analysis showed that DEGs were significantly enriched in pathways related to intestinal digestion and absorption, cell cycle and proliferation, and growth hormone synthesis, secretion, and action. Metabolomic analysis revealed that the primary enriched metabolic pathways in the Tub vs. MD comparison included arginine biosynthesis, the pentose phosphate pathway, and the citric acid cycle. Integrated multi-omics analysis revealed the co-enrichment of glycolysis/gluconeogenesis, nicotinate and nicotinamide metabolism, and arginine and proline metabolism pathways, with genes such as eno1, nmrk1, and oat regulating pyruvate metabolism, NAD⁺ regeneration, and GABA synthesis, respectively. In summary, dietary T. tubifex supplementation improved the growth performance and health status of M. pellegrini larvae by optimizing intestinal morphological structure and gut microbiota composition, as well as activating key metabolic pathways.

Tetrodotoxin (TTX) is a potent neurotoxin widely distributed in pufferfish and other marine organisms, yet its microbial biosynthetic basis remains unresolved because no definitive bacterial TTX gene cluster has been identified. This study develops a hypothesis-generating comparative-genomic framework to prioritize bacterial genomes for experimental investigation of TTX-related metabolism; it does not demonstrate bacterial TTX biosynthesis. Thirteen genomes representing Pseudoalteromonas, Cytobacillus, Shewanella, and Vibrio were analyzed using whole-genome comparison, average amino acid identity (AAI), and a weighted functional-prioritization score. Candidate homologous gene families were assigned to four mechanistic groups: scaffold formation and nitrogen incorporation (Group A), redox tailoring and polyoxygenation (Group B), structural tailoring and rearrangement (Group C), and transport, regulation, and ecological support (Group D). The AAI structure revealed both closely related Vibrio lineages and deeply divergent genera, enabling interpretation of functional enrichment against contrasting genomic backgrounds. Cytobacillus gottheilii 1839 and Pseudoalteromonas tetraodonis DSM 16,099 had the highest cumulative scores, whereas Vibrio representatives showed moderate or partial enrichment profiles. These rankings reflect the distribution of hypothesized functional markers, rather than validated TTX-production capacity. Groups A and B were more discriminating than the broadly distributed Groups C and D. Accordingly, C. gottheilii 1839 and P. tetraodonis DSM 16,099 are proposed as high-priority targets for integrated metabolomics, transcriptomics, targeted gene disruption, and pathway-mining studies. The results support a dispersed, multi-module working hypothesis for microbial contribution to TTX-associated ecology, while emphasizing that the pathway, its products, and the causal role of individual strains remain to be experimentally resolved.

Phycoerythrin (PE), a marine phycobiliprotein derived from Hypnea valentiae, was extracted, characterized, and evaluated for its potential application in a topical cosmeceutical formulation. The extraction yielded 6.35 mg/g (wet biomass), and spectral analysis confirmed pigment integrity. PE exhibited strong antioxidant activity, with DPPH radical scavenging increasing from 32.4% to 78.6% (20–100 µg/mL) and an IC₅₀ of 46.8 µg/mL, while the ABTS assay showed an IC₅₀ of 41.3 µg/mL. Anti-inflammatory activity revealed IC₅₀ values of 52.1 µg/mL (PE extract) and 60.5 µg/mL (PE cream), compared to 46.6 µg/mL for diclofenac sodium. Antimicrobial analysis demonstrated concentration-dependent activity. HV-PE showed moderate inhibition, whereas the PE-infused cream exhibited enhanced efficacy, with zones of inhibition up to 1.77 cm (Staphylococcus aureus), 1.81 cm (Bacillus subtilis), 1.96 cm (Escherichia coli), and 2.11 cm (Staphylococcus epidermidis) at 1000 µg/mL. MIC/MBC values further confirmed improved antibacterial performance of the cream (e.g., S. aureus: 52.34/46.21 µg/mL) compared to HV-PE. The formulated cream showed suitable physicochemical properties, with pH 7.12 (control: 7.48) and improved spreadability (80.71 g·cm/s vs. 74.79 g·cm/s). The SPF increased from 12.08 (control) to 24.04 (PE cream). Zebrafish toxicity studies indicated no observable adverse effects, confirming biocompatibility. Overall, PE demonstrates significant antioxidant, anti-inflammatory, antimicrobial, and photoprotective properties, supporting its application as a multifunctional cosmeceutical ingredient.

Graphical Abstract

Long non-coding RNAs (lncRNAs) are increasingly acknowledged as key players in various biological processes. However, the role of these lncRNAs in the response of cnidarians to the reverse development process remains unexplored. We conducted a genome-wide analysis of lncRNAs in immortal jellyfish (Turritopsis dohrnii) to examine their response to reverse development process across a substantial dataset of 82 RNA-seq samples. We identified 8,805 high-confidence lncRNA candidates, which are characterized by a shorter average length of 640 nucleotides and fewer exons (on average 1.41), compared to mRNAs. Remarkably, 79.73% of these lncRNAs were found to be species-specific among the thirteen jellyfish species. Within 836 lncRNAs and 1,395 mRNAs that are highly correlated with the reverse development, the key genes involving DNA repair, cell cycling, differentiation, and apoptosis (e.g., Tspan4, Aifm2, Wwox, eIF3C and those of the p53 signaling pathway and the cAMP signaling pathway) exhibited progressively increasing expression levels throughout the reverse stages. Among 64 lncRNA-mRNA pairs with putative trans- and cis-regulatory effects, the lncRNA (MSTRG.37048.1) exhibited strong correlation with Tspan4, Wwox and PIGA genes during the reverse stages. Our study provides a candidate lncRNA resource and prioritizes lncRNA-associated gene pairs potentially related to life-cycle reversal in T. dohrnii.