Marine Biotechnology最新文献

Vitamin C (VC) is an essential micronutrient known to significantly promote growth and enhance immunity in aquatic organisms. For crustaceans, dietary VC is a critical requirement for proper development. To assess the effects of VC supplementation on juvenile Chinese horseshoe crabs (Tachypleus tridentatus), first instar juveniles were subjected to various concentrations of VC in the aquatic environment. The objectives of this study were to determine the optimal VC concentration for the growth and survival of juvenile horseshoe crabs based on experimental records; to investigate the effects of VC on their gene expression through transcriptomic analysis; and to examine the impacts of various VC concentrations by measuring enzyme activities. The experimental results showed that the optimal VC concentration for molting was 30 mg/L (medium concentration), while 90 mg/L (high concentration) was optimal for survival. The effects of VC were specifically manifested by up-regulation of cytochrome c-like and down-regulation of ATP synthase F0 subunit 6 and increased alkaline phosphatase levels, which accelerated energy absorption and promoted rational energy allocation. At moderate-to-high concentrations, VC up-regulated the expression of papain family cysteine protease and partially up-regulated β-actin, while down-regulating ribosomal protein L29 (RPL29) and rho-related proteins. This expression profile ensured the precise execution of apoptosis and cell division/differentiation. Additionally, downregulation of RPL39 by VC enhanced translation efficiency. Concurrently, up-regulation of RPLP2, protein component of the small (40 S) ribosomal subunit, and RPL35, along with elevated alkaline phosphatase levels, collectively improved cellular immunity and repair capacity. Overall, these results confirm that VC promotes the growth and development of T. tridentatus.

Red seaweeds are increasingly recognized as rich sources of bioactive compounds with promising applications in health promotion, yet their mechanisms of action in human systems remain underexplored. This study investigates the safety and immunomodulatory potential of two red seaweed-derived compounds, R-phycoerythrin (R-PE) and floridoside, and phycobiliprotein-rich extracts from two species of red algae, Acrochaetium secundatum and Gracilaria gracilis. In vitro assays were conducted using Caco-2 intestinal epithelial cells and THP-1 macrophages. Assessed endpoints were cell viability (via a panel of three fluorescence-based assays), intracellular reactive oxygen species (ROS) levels, and cytokine secretion (interleukin-6 (IL-6) and interleukin-8 (IL-8)). Both pure compounds and the seaweed extracts exhibited minimal cytotoxicity. R-PE concentration-dependently increased both IL-6 and IL-8 secretion in THP-1 macrophages, starting at our lowest tested concentration of 3.125 µg mL^-1, whereas floridoside had no detectable effect on cytokine levels. Both compounds elevated ROS production in Caco-2 cells under basal conditions at concentrations (ge) 50 µg mL^-1. R-PE content in the seaweed extracts was quantified at 2022 µg g^-1 wet weight (WW) for A. secundatum and 170.6 µg g^-1 WW for G. gracilis. At exposed concentrations of 1000 µg mL^-1, both extracts significantly increased IL-8 secretion in THP-1 macrophages, with A. secundatum inducing a stronger response (127%) compared to G. gracilis (116%) (p = 0.10). These findings suggest limited bioactivity of floridoside under the tested conditions, but support an immunostimulatory potential of R-PE and red seaweed phycobiliprotein extracts. This study emphasizes the value of investigating both isolated compounds and whole seaweed extracts, as seaweed extracts can offer a more accessible, scalable, and cost-effective alternative to purified compounds, particularly for highly abundant bioactives.

This study aimed to investigate the relationship between the survival rate of Litopenaeus vannamei (L. vannamei) and its gut microbiota. The experiment was divided into two groups: the high survival group (PC, survival rate was 97.57%) and the low survival group (NC, survival rate was 25.79%). 15 healthy individuals were randomly selected from each group, and their intestinal contents were collected. Using the Illumina Hiseq high-throughput sequencing to explore the diversity of microbial structure and potential function in the gut of shrimp. The results showed that the alpha diversity and relative abundance of Bacteroidetes, Cyanobacteria, Mucoromycota, Ascomycota, Robiginitalea, Algoriphagus, Roseobacter, Muricauda, and Ruegeria were significantly increased in the high survival rate group, and the intestinal microorganisms affect the health of L. vannamei through multiple metabolic pathways. This experiment further explored the relationship between the survival rate of L. vannamei and intestinal microorganisms, laying a theoretical foundation for strategies to improve its survival rate.

Copper (Cu) is a common heavy metal pollutant in aquatic environment, jeopardizing the life safety of aquatic animals. This study aims to investigate the effects of Cu²⁺ stress on the serum biochemical indicators and alternative splicing(AS) of the liver in rainbow trout. In this study, rainbow trout were divided into a control group and 3 treatment group (75 µg/L, 150 µg/L, and 300 µg/L of Cu²⁺), which were stressed for 4 d, and restored for 2 d. We determined the dynamics of serum antioxidant indices, and analyzed the changes in liver AS by RNA-seq. The results showed that T-SOD, CAT and MDA were significantly increased during Cu stress and recovery, whereas the LDH content in the treated group showed a tendency to increase and then decrease. By analyzing the RNA-seq results, we identified 23,901 AS events from 11,062 genes. Analysis by KEGG enrichment revealed that the PPAR signaling pathway, fatty acid degradation, pyruvate metabolism, fatty acid biosynthesis, drug metabolism involving other enzymes, and propionic acid metabolism signaling pathways coexisted in multiple comparison groups. In conclusion, Cu stress induces oxidative stress and affects lipid metabolism in the liver of rainbow trout, and alternative splicing plays an important role in regulating the organism’s response to Cu stress. The present study provides a reference for the prevention and control of heavy metal pollution in aquatic environment.

Efficient DNA extraction is critical for high-throughput genotyping in aquaculture breeding programs, where cost, speed, and data quality must be balanced. This study compared five rapid extraction methods—HotSHOT, Chelex, Tween, wax-coated dipstick, and bare dipstick—against a conventional cetyltrimethylammonium bromide (CTAB) protocol for use in Lates calcarifer (barramundi) genotyping. DNA yield, purity, and integrity were measured by spectrophotometry, fluorometry, and Agilent TapeStation. Performance was tested in microsatellite genotyping, tyrosinase-related protein 1b (TYRP1b) gene sequencing, and single nucleotide polymorphism (SNP) genotyping on the Tecan Allegro Targeted Resequencing V2 platform. CTAB produced the highest-quality DNA (30.3 ± 17.4 ng/µL; A260/A280 = 1.91 ± 0.26; DIN = 8.78) with reliable results in all assays. Despite lower quality (1.07 ± 0.30 ng/µL; A260/A280 = 1.44 ± 0.18; DIN ≈ 1.6), HotSHOT performed similarly: SNP concordance with CTAB averaged 82.3%, microsatellite amplification reached 93.1% (vs. 99.3% for CTAB), and all HotSHOT samples yielded high-quality TYRP1b sequences. Chelex, Tween, and dipstick methods had lower success, likely due to inadequate yield and purity. HotSHOT was the most effective rapid alternative to CTAB, with significantly higher SNP concordance (82.3% vs. others; p < 0.005). These results show that method choice strongly influences target-capture genotyping success and support HotSHOT as a cost-effective, scalable option for aquaculture genomics.

Fisheries-induced evolution (FIE) poses a critical threat to global fisheries sustainability, but the molecular mechanisms that translate harvesting pressure into rapid, heritable trait changes remain largely unknown. Here, using a multi-generational experimental evolution approach with the marine medaka (Oryzias melastigma), we investigated divergence under different size-selective harvesting regimes. We observed phenotypic divergence under different size-selective harvesting regimes. This divergence correlated strongly with the heritable shifts in the expression of key components of the growth hormone/insulin-like growth factor (GH/IGF) axis. Strikingly, lines selected for large body size exhibited an upregulation of gh gene expression by several orders of magnitude compared to other lines, implicating the regulation of this axis as a key molecular driver underlying the observed divergence. Conversely, intense selection against large size prompted a complex adaptive response involving a shift in body allometry rather than a simple reduction in size, suggesting the influence of underlying physiological constraints. Our findings highlight heritable regulatory divergence as a plausible and rapid candidate mechanism contributing to FIE. They provide a crucial mechanistic hypothesis and a foundation for developing evolution-aware strategies for sustainable fisheries management, though further studies isolating selection from other potential drivers, such as adaptation to captivity, are warranted.

To identify sex-biased gene and miRNA expression during the critical period of sex differentiation in the prawn Macrobrachium rosenbergii, we performed whole-body RNA sequencing of males and females at post-larval days 40 (PL40) and 70 (PL70). We obtained a total of 18,244 known and 7,063 novel mRNAs, along with 1,474 known and 1,049 novel miRNAs. A differential expression analysis revealed 1,323 sex-biased genes and 34 sex-biased miRNAs as well as seven miRNA-mRNA co-expression pairs, including two pairs associated with sex differentiation. The top 30 GO terms and KEGG pathways associated with sex-biased loci at PL40 and PL70 were evaluated. Four genes and three miRNAs with potential roles in sex differentiation were identified. Notably, through dual-luciferase reporter gene assays in 293T cells, we verified that the miRNAs let-7b and miR-9-5p regulate the expression of the dsx gene. Our research provides new insight into the sex differentiation mechanisms in M. rosenbergii.

In recent years, extreme weather conditions, such as high temperatures, frequently occur owing to increases in human activities. Fenneropenaeus chinensis is a commercially cultured shrimp with females exhibiting relatively high growth performance. In this study, we investigated the effects of high temperature at the larval stage on the development and sex differentiation of F. chinensis. High-temperature stress increased the female ratio, shortened the developmental time, and decreased the survival rate at each stage. However, genetic sex identification indicated that sex reversal had not occurred. Under high-temperature stress, females showed a relatively highly positive response pattern in gene expression, and responded to this stress by upregulating genes in multiple pathways, particularly for tissue repair. Differentially expressed genes between the high-temperature and control groups at each larval developmental stage were mainly involved in constructing cuticle proteins. Therefore, high temperatures might accelerate the larval development process, resulting in changes in the expression of genes related to epidermal growth, because larval development of Penaeus shrimp is accompanied by a continuous molting process. Simultaneously, high temperatures also caused injury to the body. Because females showed a comparatively positive response pattern of gene expression, they must have comparatively high tolerance to high temperatures. Comparatively serious body injury in male shrimp resulted in a high mortality rate, eventually leading to an imbalance in sex ratio. This research revealed the molecular mechanisms of sex ratio imbalance under the effects of high-temperature stress during the larval stage of F. chinensis, and provides a reference for shrimp farming in the context of global warming.

Lung cancer is one of the leading causes of death worldwide, and chemotherapy, despite being one of the main methods of treating this type of cancer, has several adverse side effects. Therefore, recent pharmaceutical research has focused on finding alternative treatments with natural sources and fewer side effects. Toxins from the Cnidaria phylum have shown potential since they contain bioactive proteins and peptides with anticancer properties. This study investigated the effects of Stichodactyla haddoni (S. haddoni) Sea Anemone Extract (SAE), a species from this phylum, on A549 lung cancer cells and NIH3T3 (embryonic mouse fibroblast cells). SAE was prepared, and the cells, A549 and NIH3T3, were treated with a series of concentrations (50–300 µg/mL) from the extract. The cell survival rate was measured after 24, 48, and 72 h using an MTT assay. The cell cycle distribution and intracellular reactive oxygen species (ROS) production were measured using flow cytometry. The expression level of KCNC4, SCN9A, and YAP1 genes was reported using real-time PCR. The IC50 values of the SAE in the A549 cell line were 50, 67, and 70 µg/mL after 24, 48, and 72 h, respectively. SAE exhibited dose-dependent cytotoxicity in both A549 lung cancer cells and NIH/3T3 fibroblasts; however, a lower IC₅₀ value was observed in A549 cells (50 µg/mL) compared with NIH/3T3 cells (67 µg/mL) after 24 h, suggesting preferential toxicity toward cancer cells. With an increase in the concentration of SAE from 25 to 75 µg/mL, the percentage of apoptotic cells increased. In addition, the 50 µg/mL concentration of SAE significantly increased intracellular ROS and decreased the percentage of S-phase cells in the cell cycle after 24 h. KCNC4, SCN9A, and YAP1 expression levels were lower compared to the control group. S. haddoni SAE is a potential natural anticancer agent that affects KCNC4 and SCN9A in a concentration-dependent and time-independent manner.

Graphical Abstract

Kunitz-type protease inhibitors are well-known protease inhibitors found in various organisms, consisting of approximately 60 amino acid residues and featuring three disulfide bridges with a unique cysteine (Cys) framework. Among venomous animals, KTTs inhibit voltage-gated ion channels. In this study, we identified eight novel KTTs in the TTX-bearing flatworm Planocera multitentaculata, naming them Pm-KTT-1 through -8. These Pm-KTTs share 37.9–46.5% amino acid sequence identities with BPTI and DTX-K. Additionally, since Pm-KTTs contained conserved amino acid residues involved in the inhibition of trypsin and potassium channels, we speculated that Pm-KTTs act as inhibitors of trypsin and potassium channels. Recombinant expression of Pm-KTT-1 through -5 inhibited trypsin activity. Moreover, Pm-KTT-4 regulated Drosophila K⁺ channels in Shaker and Shal. Furthermore, Pm-KTT-4 functioned as a gating modifier, unlike typical KTTs in other venomous animals. These findings provide the first molecular and functional characterization of toxic polypeptides in P. multitentaculata, expanding our understanding of the evolutionary diversity and biological roles of Kunitz-type toxins.