Marine Biotechnology最新文献

This study assessed the optimum dietary vitamin B₁₂ requirement of Pacific white shrimp, Penaeus vannamei, for growth, feed efficiency, hemocyte counts, innate immunity, and ammonia stress resistance. Semi-purified experimental diets were prepared by adding vitamin B₁₂ at 0.0, 0.5, 1.0, 2.0, and 4.0 mg/kg (Con, CB0.5, CB1.0, CB2.0, and CB4.0) and a negative control (NCon) diet was prepared with 0.3% tetracycline hydrochloride. Four replicate groups of shrimp (0.17 ± 0.01 g, 32 shrimp per tank) were fed one of the diets at 3–6% of body Weight for 8 weeks. CB2.0 diet significantly increased weight gain and feed efficiency of the shrimp compared to Con diet. The expressions of insulin-like growth factor (IGF)-1, IGF-binding protein, regulatory-associated protein of mammalian target of rapamycin-like, crustin, methylmalonyl-CoA mutase, and methionine synthase-like genes in hepatopancreas were significantly upregulated with increasing dietary vitamin B₁₂ levels. Total hemocyte count, nitroblue tetrazolium, lysozyme, and antiprotease activities were significantly increased at higher vitamin B₁₂ inclusion levels above 1.00 mg/kg. Phenoloxidase, superoxide dismutase, glutathione peroxidase activities, and survival during the ammonia challenge were significantly higher in C2.0 group than in Con group. After the challenge test, C4.0 and C1.0 groups exhibited significantly higher nitroblue tetrazolium and phenoloxidase activities, respectively. Increasing dietary vitamin B₁₂ levels linearly increased hemolymph, hepatopancreas, and fecal vitamin B₁₂ levels. The polynomial regression analysis of final body weight indicated that the optimum dietary vitamin B₁₂ requirement for juvenile Pacific white shrimp is 2.02 mg/kg.

Leishmaniasis is a neglected tropical disease posing significant global health challenges. Given the limited effective treatment options and associated constraints, many patients are unable to complete therapy. In this study, we report the remarkable leishmanicidal activity of onnamides derived from the marine sponge Theonella sp. against the promastigote form of Leishmania major (IC₅₀ = 0.2–140 nM) and demonstrate their selectivity through cytotoxicity assessments on human hepatoma HepG2 cells. Structural-activity relationship (SAR) analyses were conducted using 6,7-dihydro-onnamide A and its analogs. Furthermore, we compared the action mechanisms of amphotericin B, the primary drug currently used for treatment, and the obtained onnamides. Based on biological evaluations and SAR studies, onnamides can be considered promising candidates for anti-leishmanial chemotherapy, warranting further investigation.

Triploid cyprinid fish (TCF, 3N = 150) is a novel hybrid fish showing great disease resistance during aquaculture processes. However, the majority of Aeromonas strains act as opportunistic pathogens that can cause a variety of diseases and pose a notable health risk. In this investigation, a novel Aeromonas sp. AS1-4 was retrieved from the spleen (SPL) of moribund cyprinid fish. Whole genome sequencing (WGS) was employed to characterize its virulence features and signal regulation. Thereafter, TCFs were infected with strain AS1-4 for pathological analysis. Strain AS1-4 challenge could cause abnormal glycogen deposition in the liver (LIV) of TCFs, accompanied by significant alteration of physiological response. Furthermore, expression patterns of pivotal immune-related genes were markedly elevated in TCFs post-infection. Transcriptomic analysis revealed that strain AS1-4 infection may exert a profound impact on insulin signaling pathway and steroid biosynthesis. These results may contribute to the comprehension of molecular characteristics in fish infected with Aeromonas sp. AS1-4.

Litopenaeus vannamei exhibits strong salinity adaptation; however, its survival and growth are significantly reduced in freshwater environments. To investigate the response mechanisms of L. vannamei to freshwater conditions, gill tissues from shrimp cultured for 30 days in both freshwater and seawater environments were used as experimental material in this study. Transcriptome sequencing was performed using the Illumina platform to analyze differentially expressed genes (DEGs) and regulatory pathways associated with salinity stress. Additionally, real-time quantitative PCR was employed to validate the transcriptome findings. A total of 1173 DEGs were identified between the groups, including 408 upregulated and 765 downregulated genes. These DEGs were primarily associated with pathways related to ATP binding, metabolic processes, oxidative phosphorylation, purine metabolism, and phagosome formation. Litopenaeus vannamei appears to adopt to salinity stress by enhancing energy metabolism pathways such as oxidative phosphorylation to meet the increased energy demands of osmoregulation. The upregulation of the glutathione metabolism pathway likely contributes to mitigating oxidative damage induced by salinity stress. Furthermore, the enrichment of genes in the structural constituent of cuticle pathway suggests a role in ion regulation and maintenance of osmotic balance. This study provides foundational data for advancing the understanding of physiological response mechanisms in L. vannamei under freshwater aquaculture conditions.

Chronic wounds and skin ulcers pose significant challenges to healthcare systems globally, necessitating innovative approaches to accelerate healing processes. Biomaterial-based therapies have emerged as promising solutions for tissue regeneration. This study focuses on valorization of sea urchin waste toward the development and characterization of collagen-based scaffolds added with polyhydroxynaphthoquinone (PHNQ) antioxidants, successfully incorporated into biomaterials at optimal ratio, enhancing scaffold stability and integrity. Water uptake, mechanical properties, and degradation kinetics of the composite scaffolds were evaluated and compared with controls. Biocomposites were also tested for cytotoxicity. Results indicate that composite scaffolds exhibit superior chemical stability and slower degradation rates, attributed to strong interactions between collagen and PHNQs. This aspect was explored also through in silico investigations by means of tight binding molecular dynamics methods. It has been found that a covalent bond forms between the selected collagen representative and one PHNQ. Furthermore, the antioxidant activity of PHNQs was retained in the composite scaffolds, providing additional therapeutic benefits under the perspective application of regenerative medicine. Normal human dermal fibroblasts (NHDF) exposed to the combination of collagen and PHNQs remained viable. Overall, these findings highlight the potential of sea urchin food waste in a valorization chain, offering added value through the production of collagen-based composite scaffolds.

Natural products, specifically secondary metabolites, produced by marine organisms, play crucial roles in their survival and performance. Research on natural products derived from marine organisms, particularly soft corals, has been ongoing for over 30 years in Taiwan, resulting in the isolation and identification of over 2000 unique compounds from 100 species of soft corals. These studies have not only uncovered bioactive compounds with potential useful applications but have also provided insights into the chemical evidence for the taxonomy of soft corals as well as the biological functions of these products within soft corals. Following the central dogma of molecular biology, this review notes that, according to the biosynthesis pathways, the types of natural products identified for seven clades of soft corals align with the updated phylogenetic system of soft corals based on DNA sequencing analysis. Thus, these natural products can serve as chemical evidence to support our understanding of soft coral taxonomy. Furthermore, to understand the influences of geographic factors on the production of natural products in soft corals, we compiled data on natural products from species repeatedly collected at different locations around Taiwan. Interestingly, the oxidation levels of briaranes in Briareum stechei and Junceella fragilis, and cembranes in Sclerophytum flexibile and Lobophytum crassum, tended to increase with rising seawater temperatures, while other soft corals also exhibited different metabolite profiles across spatial and temporal scales. Finally, we highlight the challenges and future perspectives in studying natural products from soft corals and propose that recent advancements in techniques, which offer comprehensive tools, such as mass spectral molecular networking, can significantly improve the elucidation of secondary metabolite structures. By addressing these challenges and leveraging new technologies, future research can provide novel insights into the roles that natural products play in marine chemistry. Collectively, this will contribute to a better understanding of marine biodiversity, the chemical dynamics of marine chemical ecology, and potential biotechnological applications.

The zig-zag eel (Mastacembelus armatus) is an economically important aquaculture species in south China. Currently, the genome-wide association study (GWAS) for growth traits of zig-zag eel was first performed. A total of 175 zig-zag eels were measured for body height (BH), body length (BL), body weight (BW), body thickness (BT), head length (HL), and total length (TL) and genotyped using whole genome resequencing. After quality control, a total of 13,844,114 high-confidence SNPs were detected uniformly across 24 chromosomes. After GWAS, a total of 2, 1, 2, 2, 1, and 2 SNPs were significantly associated with BH, BL, BW, BT, HL, and TL traits, respectively. In addition, many candidate genes surrounding these SNPs have been shown to be closely associated with growth, including ppt1, cap1, lnr, and fgfr2. In all, these results lay a good foundation for exploring the molecular basis of growth regulation and molecular marker-assisted selection.

The microalgae Euglena holds promise for biofuel production due to its high lipid content. However, the lipid productivity of current species/strains for biofuel production remains suboptimal due to limitations in strain selection. Therefore, this study aims to isolate and identify novel Euglena species or strains with high biomass and lipid productivity to enhance biofuel production from a desirable environment. Malaysia’s tropical climate with abundant sunlight and water resources provides an ideal environment for microalgae cultivation. Therefore, this research is conducted in Malaysia for effective utilization. Accordingly, water samples were collected from various Raja Musa Forest Reserve habitats in Selangor, Malaysia including peatland, paddy fields and the Kuala Selangor River. The samples were isolated using the single-cell pickup technique. The isolated samples were cultivated using the test tube system. The biomass and lipid productivity were quantified using the gravimetric technique. The top novel lipid-producing Euglena strain SAB-3 was identified through scanning light microscopy and phylogenetic analysis of the ITS2 region. The Sab-3 was placed within the Euglena gracilis clade through this analysis, showing close similarity to the E. gracilis SAG strain. SAB-3 dominated high biomass productivity (0.704  g L¹ day¹), high lipid productivity (0.051 g L¹ day¹) and relatively high specific growth rate (1.091 day¹) with a shorter cultivation time of 7 days compared to the E. gracilis (NIES-48).

With few preventive strategies available against nodavirus (NNV) in aquaculture, therapeutic applications remain underexplored. This study aimed to peptide-based treatments disrupting critical stages of its viral life cycle. Thus, we designed and synthesized seven low-molecular-weight peptides (P1–P7) based on predicted binding regions of the capsid protein from the red-spotted grouper nervous necrosis virus (RGNNV) genotype to mimic viral capsid regions. Although in silico predictions suggested limited direct antiviral activity, in vitro assays using the E-11 cell line and in vivo trials in RGNNV-infected European sea bass (Dicentrarchus labrax) juveniles yielded promising results. The peptides, particularly when co-administered individually or as P3 + P4 and P5 + P6 combinations with the virus, disrupted RGNNV attachment in vitro. Moreover, they exhibited cross-reactivity against the striped jack nervous necrosis virus (SJNNV) genotype and both RGNNV/SJNNV and SJNNV/RGNNV reassortants. Treatment of RGNNV-infected sea bass significantly increased the relative percent survival, ranging from 81.3% for P4 to 62.5% for P3 and P3 + P4, while reducing viral load within 48 h post-treatment without altering systemic antiviral immune responses, tested through the transcriptional levels of mx gene in the head-kidney. Notably, peptide P4 partially inhibited viral replication in vitro at the same time-point when cells were pre-treated for 24 h, likely through modulation of host immune responses. These findings highlight the potential of targeted peptide-based therapies as a promising antiviral therapeutic strategy against NNV infections.

Growth differentiation factor 9 (GDF9) is a member of the transforming growth factor-β (TGF-β) superfamily and is expressed in an oocyte-specific manner. It plays a crucial role in the early stage of ovarian development. Japanese eel (Anguilla Japonica), a spawning migration teleost, has artificial reproduction still under investigation. Aimed at developing a novel method for the successful artificial reproduction of Japanese eel, in the present study, the role of GDF9 in the regulation of early ovarian development was investigated. The Gdf9 gene in Japanese eel was 1293 bp in length, coding for 430 amino acids. Expression analysis in different tissues showed that gdf9 is highly expressed in the ovary, and the gdf9 mRNAs are localized in early developmental oocytes. Injection experiments showed that GDF9 significantly increased the gonadosomatic index in Japanese eel. However, histological observations indicated that GDF9 injection alone was insufficient to overcome the cortical alveolus stage and initiate vitellogenesis in Japanese eel, which is consistent with the lack of significant changes in serum estradiol and vitellogenin levels. Transcriptomic analysis revealed that GDF9 is involved in various molecular functions and physiological processes within the ovary. Overall, our findings suggest that GDF9 plays a regulatory role in the early ovarian development of Japanese eel, possibly by promoting the formation and activation of primordial follicles. These findings offer novel evidence for understanding the regulation of early ovarian development in Japanese eel and provide a valuable foundation for advancing artificial breeding in this species.