Marine Biotechnology最新文献

Megalocytivirus pagrus 1 infection is a World Organisation for Animal Health-listed aquatic animal disease caused by a virus species comprising the RSIV, ISKNV, and TRBIV genogroups. Here, we integrated comparative genomics and immunoinformatics to prioritize a multi-epitope protein construct, pMEV, and to design a DNA vaccine candidate encoding it, with emphasis on RSIV-type infection relevant to rock bream aquaculture. Analysis of 61 complete genomes identified 28 core gene clusters, from which myristoylated membrane protein (MMP) and major capsid protein (MCP) were prioritized as source antigens for epitope screening. Four cytotoxic T-cell, five helper T-cell, and five linear B-cell epitope candidates were selected based on sequence-based screening and exploratory peptide–MHC docking. The selected epitopes were assembled with rock bream beta-defensin-3, PADRE, and peptide linkers to generate the 283-aa pMEV construct. Sequence-based physicochemical analyses indicated properties relevant to subsequent structural and expression-based evaluation, while computationally refined structural modeling identified nine putative conformational B-cell epitope regions. TLR3 docking, normal mode analysis, and a 200-ns molecular dynamics simulation characterized the structural behavior of the selected computational complex without inferring receptor activation. C-ImmSim further generated model-dependent generic humoral and helper T-cell-associated response patterns within a mammalian-based simulation framework. Finally, the pMEV coding sequence was codon-optimized and incorporated into an in silico pcDNA3.1(+)-based DNA vaccine design. Collectively, this study provides a comparative genomics-guided framework for prioritizing an experimentally testable multi-epitope DNA vaccine candidate against M. pagrus 1, while construct expression, immunogenicity, and protective efficacy remain to be evaluated experimentally.

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Ca²⁺ homeostasis regulates endoplasmic reticulum (ER) stress and lipid metabolism and is involved in the stress response in mammals. However, how these regulatory pathways respond in aquatic animals exposed to stressful environmental conditions remains unclear. In this study, we used siRNA to inhibit the expression levels of Bip, SERCA, IP₃R, and MCU, which are involved in regulating Ca²⁺ homeostasis in the hepatopancreas of Penaeus vannamei. An ammonia stress experiment was subsequently conducted (stress concentration of 11.3 mg/L) to measure parameters associated with ER stress, Ca²⁺ homeostasis, and lipid metabolism. This study was performed to verify the roles of Ca²⁺ homeostasis in regulating ER stress and lipid metabolism in P. vannamei subjected to ammonia stress. Interfering with Bip gene expression limited the unfolded protein reaction (UPR), reduced Ca²⁺ transport into the ER, and promoted Ca²⁺ efflux. These findings indicate that Bip plays a critical role in the regulation of ER stress and Ca²⁺ homeostasis. Interfering with SERCA gene expression exacerbated ER stress responses and promoted the UPR. This interference also reduced ER Ca²⁺ leakage through IP₃R and aggravated the cellular energy deficiency state, indicating that SERCA is crucial for maintaining ER Ca²⁺ levels and managing energy balance. Reduced IP₃R gene expression inhibited ER stress responses by decreasing Ca²⁺ efflux from the ER. This reduction in Ca²⁺ transport into the ER and mitochondria resulted in cellular energy deficiency and modulated lipid metabolism, highlighting the role of IP₃R in Ca²⁺ signaling and metabolic regulation. Interfering with MCU gene expression alleviated ROS-induced ERs, led to ER Ca²⁺ overload, and resulted in cellular energy deficiency while enhancing lipid metabolism. These findings indicate that MCU is vital for regulating mitochondrial Ca²⁺ uptake and cellular energy metabolism under stress conditions. These results suggest that reducing ER Ca²⁺ efflux and maintaining ER Ca²⁺ homeostasis represent candidate molecular targets whose contributions to ammonia tolerance in shrimp are worth investigating in future studies.

In this study, a skin-derived cell line, designated RTS, was established from red tilapia (Oreochromis spp.) using the tissue explant culture method. Cell outgrowth from skin explants was first observed on day 6 of primary culture, and the cells could be continuously subcultured with stable adherent growth. To date, the cell line has been maintained for more than 88 passages in vitro. Growth curve analysis demonstrated that RTS cells proliferated in DMEM, MEM, and L-15 media supplemented with 15% fetal bovine serum, with DMEM exhibiting the most favorable support for cell proliferation. Chromosome analysis showed that the diploid chromosome number of RTS cells was 2n = 44. Molecular identification based on a partial mitochondrial COI fragment indicated that RTS belonged to the genus Oreochromis and was phylogenetically closest to O. mossambicus. In addition, RTS cells were amenable to plasmid transfection, with a transient transfection efficiency of 35.2 ± 3.8% using pEGFP-N3. In response to Streptococcus agalactiae challenge, immune-related genes in RTS cells including MyD88, NF-κB, NOD2, TLR2, and IL-2 showed dynamic transcriptional changes. Under hyperosmotic treatment (532 ± 13 mOsm/kg), ostf1, HSP70, NKCC1, and nka exhibited distinct temporal expression patterns, indicating osmotic stress-responsive transcriptional changes. These results demonstrate that RTS is a stable and manipulable red tilapia skin-derived cell line and may serve as a useful in vitro model for studies of immunity and osmotic stress in red tilapia.

In the present study, we report the effects of soy protein concentrate (SPC) on growth parameters, liver morphology and hepatic transcriptomic response on totoaba (Totoaba macdonaldi) (153 ± 0.84 g). Two experimental isoenergetic diets (IDs), each containing 44% protein and 11% lipids, were formulated by replacing 30% (SPC30) and 60% (SPC60) of fish meal with SPC and compared to a commercial diet (CD) containing fishmeal. Treatments were performed in triplicate (n = 12 per replicate) over a period of 90 days. Fish fed the CD or SPC30 diets showed no significant differences in final weight (fW: 618.4 ± 20.13 and 624.4 ± 16.97 respectively). Conversely, fish fed the SPC60 diet exhibited the lowest growth performance (fW: 260.10 ± 57.65 g, weight gained: 68.84 ± 0.94 g and specific growth rate: 0.36 ± 0.22%). Liver from totoaba fed the CD showed a typical, uniform hepatic organization. In contrast, livers from SPC30 and SPC60 groups displayed lipid vacuole infiltration in hepatocytes and central displacement of the nuclei. Functional gene enrichment analysis of transcripts revealed that biological processes (BP), such as protein catabolism (ctra, ctrb, ela1, cbpb1, cbpa1), stress responses (bfar, dab, casp8, pawr), anatomical structure development (stml2, lrig2, hgf, ret), bile acid biosynthesis (s27a2, ntcp7, nr1h4) and lipid transport (s27a2, lipe4, fabpi), were the molecular mechanisms most affected by SPC supplementation. Collectively, these BPs suggest negative effects of SPC60 supplementation in totoaba.

A major barrier to scaling marine restoration and aquaculture is the lack of reliable tools to induce invertebrate larvae to settle and metamorphose when and where needed. Although microbial cues are known to induce metamorphosis in many invertebrates, existing methods rely on natural biofilms that are variable, difficult to standardize, and unsuitable for large-scale deployment. Here we introduce ReefTiles, a non-living bacterial coating that preserves inductive activity from metamorphosis-stimulating marine bacteria in a stable, reproducible format. Using both tubeworm and coral larvae, we show that dried and inactivated bacterial films retain full settlement-inducing capacity, matching or exceeding live biofilms while eliminating concerns associated with releasing viable microbes into the environment. Viability assays confirm inactivation, and the coating adheres reliably to common substrate materials. Because ReefTiles can be manufactured and stored at scale and tailored to different inductive strains, they provide a practical microbe–based biotechnology for enhancing larval settlement in reef restoration, sustainable aquaculture, and engineered marine infrastructure.

Galectins are a family of proteins that bind specifically to β-galactosides. Their importance in innate immunity of mammals has been well-documented. However, the systematic identification and characterization of galectin gene family remain limited in teleost. In this study, we identified 13 galectin genes (lgals2, lgals2a, lgals2b, lgals3, lgals3a, lgals3b, lgals4, lgals8, lgals8a, lgals9, grp, grp-b, grp-c) from Paralichthys olivaceus genome and analyzed their tissue expressions and expressions in response to Gram-negative and Gram-positive bacterial infections in mucosal tissues (gills, intestine and skin). The P. olivaceus galections were classified into three distinct types based on carbohydrate recognition domains (CRDs). Phylogenetic and syntenic analyses revealed that these galectins are closely related to their counterparts in turbot and zebrafish. Moreover, the transcripts of the 13 galectins were widespread across all tested tissues of healthy fish and regulated following challenge with Vibrio anguillarum or Streptococcus iniae in mucosal tissues, indicating their involvement in P. olivaceus immune response to bacterial infections. The lgals2a was significantly upregulated in the three mucosal tissues by either bacterial infection, whereas lgals9 and grp were basically downregulated in these tissues by either infection. On the other hand, the lgals3b and lgals4 exhibited a bacteria-specific responsive expression as they were upregulated by V. anguillarum whereas remained stable upon S. iniae infection in the gills. We also observed a positive correlation between expression level and bacterial load for the upregulated galectin genes and a negative correlation for the downregulated galectin genes. These results suggest a functional divergence among galectin members in mucosal immunity against bacterial infection in P. olivaceus.

The use of probiotics – live microorganisms – to enhance growth and prevent disease in mariculture species is an emerging alternative to conventional methods including antibiotics, vaccines and chemical intervention. While others have reviewed specific host organisms and probiotic genera, this review synthesises the scientific literature on the use of probiotics across a range of marine organisms to identify knowledge gaps and research opportunities. We identified widespread methodological heterogeneity, making direct inter-study comparisons difficult. Despite this limitation, 86% of in vivo studies documented positive outcomes following probiotic administration. Crustacean and finfish research dominates the field, encompassing 77% of the current literature, while molluscs, macroalgae and other invertebrates remain relatively understudied despite their significant ecosystem services and contribution to aquaculture. Probiotics provide multiple reported benefits to marine hosts, including increased growth and survival, and protection against pathogens. Bacillus and Lactobacillus from terrestrial environments are the dominant probiotics used across all studies, while marine-derived probiotic genera including Pseudoalteromonas, Vibrio, Phaeobacter, Shewanella, and Halomonas showed benefits across several hosts but remain relatively underutilised. Approximately 34% of publications evaluated the use of microorganisms isolated from the same host species in which the probiotics were tested. This review highlights the opportunity for further research into underutilised autochthonous probiotic genera and development of standardised research guidelines. We propose that future research should prioritise understanding probiotic mechanisms of action, and their use in rapidly expanding and understudied systems including macroalgae and molluscs, to ensure continued productivity with minimal impact on marine ecosystems.

The Yesso scallop Mizuhopecten yessoensis was imported from Japan to western Canada in the late 1980s to establish an economically viable scallop aquaculture industry. Since this time, the industry in Canada has operated with existing genetic diversity within the broodstock, which is considerably limited relative to wild populations. The sector has not been able to realise its full potential in part due to idiopathic hatchery failures and farm stock collapses due to disease outbreaks associated with the intracellular bacterial pathogen Francisella halioticida. To support Yesso scallop production and breeding, here we generate a low-density, genotyping-by-sequencing amplicon panel using single nucleotide polymorphism (SNP) markers that are evenly spaced across the M. yessoensis genome and that show high heterozygosity in Canada and Japan. The panel can also exploit the high genetic polymorphism of the M. yessoensis genome, with de novo SNP calling identifying over 2,500 high quality SNPs within the 579 sequenced amplicons. We demonstrate the utility and versatility of this new genotyping tool for breeding applications including parentage assignment, low density family-based genome-wide association study, trait heritability evaluation to determine potential for genomic selection, and species differentiation (against the weathervane scallop Patinopecten caurinus). We did not find any genomic regions significantly associated with F. halioticida resistance but did identify potential for genomic selection. We could separate the two species based on genotypes, and did not see evidence of a past M. yessoensis x P. caurinus hybridization event within the M. yessoensis breeding population at Vancouver Island University. This low-cost genotyping panel is expected to accelerate selective breeding improvements for M. yessoensis in Canada and elsewhere.

This study presents a comprehensive approach to valorizing the red macroalga Bostrychia scorpioides (BS), collected from Oualidia lagoon, as a reservoir of compounds with biological activity. An extraction protocol combining ultrasound-assisted pretreatment with conventional maceration in 80% (v/v) hydroethanolic solvent was developed, and the recovery of phenolic compounds was maximized using response surface methodology (RSM) based on a Box–Behnken design (BBD). The model-predicted and experimentally validated optimal extraction conditions were 37.5 min of ultrasonication, an extraction temperature of 45 °C and 3.5 h of maceration, yielding a TPC of 341.45 µg GAE/g dw; the optimal extract was also rich in flavonoids and condensed tannins. In terms of bioactivity, the extract exhibited substantial antioxidant capacity, achieving 98.97% hydrogen peroxide scavenging, which strongly correlated with the phenolic concentration. Antibacterial evaluation revealed pronounced inhibition of Listeria monocytogenes, Staphylococcus aureus and Escherichia coli, with inhibition zones ranging from 9 to 19 mm and MIC values from 3.125 to 12.5 mg/mL. Crucially, cytotoxicity assessment on PBMCs demonstrated a favorable safety profile, maintaining over 85% cell viability at concentrations up to 200 µg/mL. High-Performance Liquid Chromatography (HPLC) and molecular docking simulations identified chlorogenic acid as a major bioactive constituent, displaying a high in silico binding affinity (− 8.0 kcal/mol) for aromatase, a validated target in oncological therapy. Taken together, these findings suggest that BS represents a sustainable and safe natural reservoir of antioxidant and antimicrobial compounds of interest for natural drug development.

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