Marine Biotechnology最新文献

Litopenaeus vannamei is one of the most widely farmed shrimp species worldwide, but it traditionally exhibits limited adaptability to low-salinity environments. Genetic improvement through intraspecific hybridization has been proven effective in enhancing environmental adaptability. This study aimed to elucidate the molecular mechanisms underlying the low-salinity adaptation of a hybrid shrimp strain selected through intraspecific hybridization. Shrimp were reared for 12 weeks under salinity conditions of 1 practical salinity unit (PSU) and 15 practical salinity units (PSU). By conducting a combined analysis of transcriptomics and metabolomics, we explored the low-salt adaptation mechanism of the hybrid shrimp. We found that they enhanced their adaptability through self-osmotic regulation and energy regulation. Transcriptome results revealed that genes associated with calcium-activated chloride channels, chloride transporters, and sodium-driven chloride/bicarbonate exchangers were up-regulated, suggesting enhanced ion transport capacity under low salinity. The metabolomics results indicated that key enzymes involved in glycolysis and gluconeogenesis, including phosphofructokinase and phosphoenolpyruvate carboxykinase, showed increased abundance, indicating elevated energy metabolism to support osmotic adjustment. Overall, the selected hybrid shrimp enhanced osmotic regulation by strengthening energy metabolism to improve their low-salt adaptability. These findings provide valuable insights for future genetic breeding and sustainable shrimp aquaculture in low-salinity regions.

Antimicrobial resistance is a serious threat to global public health and requires new therapeutic approaches. Antimicrobial peptides (AMP) are recognized as promising candidates to address antimicrobial resistance. AMP can disrupt cell membranes by increasing permeability and causing lysis, or they can also interact with intracellular targets to inhibit essential metabolic processes. The genus Acropora is regarded as a valuable source for bioprospecting antimicrobial compounds. In this study, we employed in silico analytical strategies to predict potential antibacterial activity using AMPs derived from transcriptomes of multiple life cycle stages of the coral Acropora digitifera, as well as from cultured cells originating from adult coral tissues. The analysis involved multiple sequence alignments, Hidden Markov models, machine learning algorithms, structural modeling, physicochemical property assessment, and molecular docking. From the transcriptomic data, 15 sequences with potential antimicrobial activity were identified. Five AMPs were further evaluated for their binding efficacy against the TolC and OprM protein channels of RND-type transporter proteins, as well as DNA gyrase B of Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. Binding free energy analysis indicated that AMP-Ad2 exhibited the most favorable interaction with the TolC channel of E. coli. AMP-Ad3 showed the highest binding affinity with the OprM channel of P. aeruginosa, while AMP-Ad15 displayed the most favorable binding energy for the TolC channel of K. pneumoniae. The strongest interaction overall was observed between AMP-Ad15 and the DNA gyrase B of K. pneumoniae. These results demonstrate the utility of in silico prediction tools for identifying AMP candidates from A. digitifera transcriptomes and provide a basis for the planned synthesis and in vitro evaluation of these peptides, aiming to assess their therapeutic potential against resistant Gram-negative bacteria.

Fish skeletal muscle serves as a crucial source of high-quality protein for human consumption. MicroRNAs (miRNAs) are important epigenetic regulators for the growth and development of skeletal muscle. Although the functions of many myogenic miRNAs have been studied, the regulatory functions of miRNAs in fish skeletal muscle have not been fully investigated. Here we show miR-125b is highly expressed in fast muscle of Chinese perch (Siniperca chuatsi) at 30–60 days post-hatching (dph), with transient downregulation during the skeletal muscle injury repair stage, implying its essential regulatory role in fast muscle growth and injury repair. Moreover, inhibiting miR-125b in Chinese perch resulted in an increase in muscle fiber diameter, the number of proliferating myoblasts and nuclei in single muscle fiber. In contrast, overexpression of miR-125b in Chinese perch led to a significant reduction in muscle fiber diameter, accompanied by a significant decrease in the number of proliferating myoblasts and the number of nuclei in single muscle fiber. Bioinformatics analysis and dual luciferase assays confirmed MyoD and Myomaker as direct targets of miR-125b. In summary, our findings demonstrate that miR-125b modulates the expression of MyoD and Myomaker, thereby regulating the proliferation and fusion of myoblasts, and ultimately controlling the hypertrophy of muscle fibers in Chinese perch. This finding holds significant relevance in unraveling the genetic mechanisms that govern the developmental traits of muscle fibers in fish during the postembryonic phase.

The unreported peptide versicotide K (1), along with known averufin (2), 1′- hydroxyversicolorin B (3), averufanin (4), and sterigmatocystin (5), was isolated from the sponge-derived fungal strain Aspergillus versicolor 01NT- 1.5.1. Moreover, the new 6,8-dimethoxyaverythrin (6) and known averythrin (7) and sclerotiotide F (8) were isolated from another sponge-derived fungus Aspergillus flavus КMM 4695 (= VO49-48.3). The antimicrobial and cytotoxic activities of the isolated compounds were studied. The obtained data on the low cytotoxicity of averufanin (4) to normal HaCaT keratinocytes and H9c2 cardiomyocytes confirms its anticancer potential for future research. The significant activity of averythrin (7) against Staphylococcus aureus growth and biofilm formation (IC₅₀ of approximately 10 µM) is the first. The anti-inflammatory activity of versicotide K (1) was predicted using the PASS online server. Moreover, SwissTargetPrediction services predicted COX2 as a possible target for 1, and the interaction of 1 with COX2 was calculated using a molecular docking approach. In in vitro experiments, versicotide K (1) reduced S. aureus infection and ischemia/reperfusion damage of H9c2 cells and prevented TNF-α induced damage of H9c2 cardiomyocytes by 24%, confirming its anti-inflammatory properties.

Light intensity, a crucial environmental factor, significantly affects the growth and physiological state of fish. This study investigated the effects of different light intensities (0, 150, 450, 650, and 1000 lx) on juvenile mandarin fish (Siniperca chuatsi) over a 66-day period. All groups achieved 100% survival, indicating that light intensity did not significantly affect survival. However, growth performance measured by specific growth rate (SGR) and weight gain rate (WGR) was highest at 150 lx. Nutritional analysis showed that crude protein and crude fat content were highest in the 150 lx group, while moisture was lowest under these conditions. Digestive enzyme activities in the liver, stomach, and intestine peaked under low-to-medium light intensities, with the highest values observed at 150 lx. Plasma cortisol levels were significantly lower at 150–450 lx than in other groups, indicating reduced stress under these conditions. In contrast, plasma melatonin levels declined with increasing light intensity and were lowest at 1000 lx. Overall, an illumination level of 150 lx was most beneficial for enhancing growth, reducing stress, and optimizing digestive enzyme activity in juvenile mandarin fish. These findings provide valuable insights for optimizing aquaculture practices and improving fish welfare and production efficiency.

Growth is an economically important traits in aquaculture. Previous studies identified ppp2ca as a candidate gene located within a major quantitative trait locus (QTL) for growth in Asian seabass. However, the molecular mechanisms underlying its role in growth regulation remain unclear. In this study, a single nucleotide polymorphism (SNP) in ppp2ca was found significantly associated with body weight. The gene was ubiquitously expressed across 11 examined tissues, with highest levels in the brain and eye, but reduced expression in the muscle of fast-growing fish. Functional assays showed that ppp2ca knockdown promoted cell proliferation, whereas its overexpression suppressed cell proliferation in an Asian seabass cell line. Two upstream mutations—a 10-bp indel and a 218-bp indel, were also identified and characterized. Dual-luciferase reporter assays demonstrated that the 10-bp insertion enhanced ppp2ca expression, while the 218-bp deletion reduced it. Permutation-based two-way ANOVA revealed a significant interaction between the 10 bp insertion and 218 bp deletion on body weight. These findings suggest that these upstream mutations in ppp2ca influence growth in Asian seabass, providing useful markers for selective breeding and key targets for future detailed functional studies on growth regulation.

Abalone, a marine mollusk with significant economic and ecological value, plays a crucial role in sustainable aquaculture. The development and application of CRISPR-Cas9 gene-editing technology have opened up a new path for improving breeding efficiency. CRISPR/Cas9-mediated gene editing has been achieved in abalones via microinjection. In this study, a gene encoding myostatin MSTN in H. discus hannai; was selected as target for conducting the CRISPR-Cas9 gene editing experiment in combination with an electroporation delivery system. Our results showed that all three sgRNAs effectively targeted and cleaved the target segment, with sgRNA1 and sgRNA2 exhibiting high in vitro activity. After electroporation, the effects of transfection on embryonic development of fertilized eggs were observed and statistically analyzed. 12.7 ± 5.4% of the fertilized eggs were damaged and deformed after electroporation. Twenty-four hours after electroporation, surviving larvae were collected for DNA extraction and sequencing. Two potential mutations within the target region of MSTN were identified by sequencing. These results provide a reference for the improvement and development of CRISPR-mediated gene editing methods in marine mollusks such as abalones.

Tetrodotoxin (TTX), also known as puffer fish venom, has gained wide popularity in recent years as an effective tool in the field of physiology, as well as a promising anesthetic and analgesic agent. However, to date, no economically viable method of TTX production has been found. In this work, using high-performance liquid chromatography with tandem mass spectrometry, we conducted a study of the dynamics of the content and ratio of TTX and its analogues (TTXs) in the eggs of captive nemerteans of the Cephalothrix simula species complex, as well as a study of TTX localization in nemertean eggs using confocal laser scanning microscopy. It has been shown that nemertean eggs and nemerteans themselves, when kept in captivity for a long time, can contain concentrations of TTXs comparable to individuals of the wild population. It was found that TTX in eggs is associated with yolk granules, for which morphological characterization was carried out for the first time. The data obtained in the work can be used as a basis for the development of a technique for keeping animals in captivity for as long as possible while maintaining/increasing their toxic potential for further toxin extraction from egg yolk.

Channa striata is a hardy fish that can thrive in various aquatic conditions; it is a good source of protein and has high economic value. This study was conducted to establish and characterize the muscle cell line of C. striata and use it to develop micro-tissue using seaweed biofilm. Explant culture was used to create a continuous muscle cell line from C. striata, which was then sub-cultured 143 times in Leibovitz L-15 medium with 10% FBS at 28 °C. They were properly cryopreserved, and after storage, 88–92% of the cells were recovered. The C. striata muscle cell line (CSM) was authenticated by examining the mitochondrial 16S rRNA gene using polymerase chain reaction. The immunophenotyping results revealed that the CSM cells were of myoblast origin, as evidenced by desmin and myosin cell markers. CSM cells showing a myogenic-like phenotype were also demonstrated through lipid droplets, which were confirmed by Nile Red staining. This cell line was devoid of mycoplasma infection. Inducing the foreign gene plasmid pEGFP-N1 resulted in a 16% transfection efficiency. Sterilized biocompatible seaweed biofilm was employed as a scaffold to grow micro-tissue using the developed CSM cell line. After 20 days of growth, this cell line produced micro-tissue on the seaweed biofilm. Seaweed biofilm is a one-of-a-kind biomaterial that has a wide range of biomedical applications, is ecologically friendly, biocompatible, and helps to improve cellular aquaculture and sustainable development.

China harbors extensive saline-alkaline water resources with considerable potential for aquaculture development. However, their utilization is constrained by high pH, elevated carbonate alkalinity, and complex ionic composition. Exopalaemon carinicauda, a commercially important shrimp species in China, is recognized for its environmental adaptability, rapid growth, desirable flesh quality, and high economic value. Owing to its resilience to diverse environments, E. carinicauda serves as an ideal model for investigating the molecular mechanisms underlying saline-alkaline adaptation in crustaceans. Yet, the genetic determinants of its alkalinity tolerance remain poorly understood, hindering selective breeding efforts. In this study, bulked segregant analysis (BSA) coupled with next-generation sequencing was employed to identify single nucleotide polymorphisms (SNPs) associated with alkalinity tolerance. DNA from individuals exhibiting extreme phenotypes was pooled, and allelic differences were assessed using Euclidean distance, deep learning, and ΔSNP-index methods. A total of 20,879,626 SNPs were detected, and seven candidate genomic regions spanning 47.53 Mb on chromosomes 4, 11, 13, 18, 26, and 36 were identified, encompassing 194 genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment revealed significant associations with GABAergic synapse, taste transduction, and vasopressin-regulated water reabsorption. Comparative transcriptomic analysis under high-alkalinity stress in hepatopancreas and gills identified 28 genes strongly linked to alkalinity tolerance, including gamma-aminobutyric acid receptor, glutamate receptor ionotropic, and basic salivary proline-rich protein. Two SNP loci, C4-2601 and C8-6550, significantly associated with alkalinity tolerance were validated through PCR-based sequencing. These findings provide critical insights into the genetic architecture of alkalinity tolerance in E. carinicauda, facilitating future genomic and marker-assisted selection strategies.