Marine Biotechnology最新文献

Extracellular vesicles and EV-enriched extracellular particles are increasingly recognized as potential mediators of intercellular communication. In coral reef ecosystems, dinoflagellate symbionts of the family Symbiodiniaceae play central roles in host metabolism, environmental acclimation, and stress responses; however, the molecular composition of extracellular particles released by cultured Symbiodiniaceae remains poorly understood. In this study, a host-isolated Symbiodiniaceae culture derived from the sea anemone Exaiptasia diaphana was established under host-free laboratory conditions for EV-enriched particle isolation and characterization. Physicochemical analysis of the recovered extracellular particle fraction showed an average diameter of 534.1 ± 63.9 nm, a polydispersity index of 0.733 ± 0.08, and an average zeta potential of − 14.57 ± 1.55 mV, indicating a heterogeneous and negatively charged extracellular particle suspension. Small RNA analysis showed that the EV-associated RNA fraction contained multiple RNA biotypes, with rRNA- and tRNA-derived reads representing the dominant annotated components, whereas miRNA-like sequences accounted for only a minor fraction of the annotated small RNA pool. Comparison against an antisense Exaiptasia diaphana CDS dataset further identified retained EV-associated small RNAs showing sequence complementarity to host coding transcripts, including cytohesin-1 and EPG5. These matches are interpreted as candidate sequence-level observations rather than evidence of functional host regulation. In parallel, miRNA-oriented analysis identified candidate miRNA-like sequences after downstream filtering. Proteomic profiling by LC–MS/MS generated 4,086 accession-level matches. After removal of uninformative entries and consolidation of duplicate protein names, 834 non-redundant named proteins were retained and classified into nine functional groups, including proteins involved in metabolism and energy production, transport and membrane trafficking, photosynthesis and chloroplast function, and signal transduction and regulation. Representative annotations included 14-3-3-related proteins, Rab/ARF family proteins, Hsp70, Hsp90, and oxygen-evolving enhancer protein. These results provide an initial qualitative molecular characterization of EV-associated molecules released by a host-isolated Symbiodiniaceae culture and serve as a baseline for future studies of algal extracellular communication and cnidarian–dinoflagellate symbiosis.

Biomineralization in mollusks, a fundamental process in marine ecosystems, is highly sensitive to anthropogenic stressors. Exosome-secreted species-specific shell matrix proteins (SMPs) are essential in biomineralization adaptation but remain understudied. Estuaries are considered unfavorable for biomineralization compared to open coastal zones and serve as an ideal research location to explore the roles of exosome-secreted species-specific SMPs in biomineralization adaptation under future rapid environmental change. Here, combining proteomics of shell matrix and mantle-derived exosomes, the high-abundance species-specific SMPs Car-TPM (tropomyosin from estuarine oyster Crassostrea ariakensis) and Cgi-GIGA6 (gigasin-6 from coastal oyster Crassostrea gigas) were taken as representatives to decipher the roles of exosome-secreted species-specific SMPs in oyster biomineralization adaptation. Tissue expression profiles and in situ hybridization revealed that Car-TPM was highly expressed in the adductor muscle and mantle, while Cgi-GIGA6 predominated in the mantle. Post-injury experiments demonstrated that Car-TPM expression upregulated quickly at 6 h, and Cgi-GIGA6 continued to be down-regulated. Knockdown of Car-TPM suppressed shell repair, whereas silencing Cgi-GIGA6 enhanced it. In vitro assays revealed that Car-TPM significantly promoted calcium carbonate precipitation and aggregation of rhombohedral calcite crystals, whereas Cgi-GIGA6 suppressed crystallization and eroded the original flat edges. These findings indicate that Car-TPM is a positive regulator of biomineralization in C. ariakensis inhabiting harsh estuarine environments, while Cgi-GIGA6 exerts a negative regulatory effect to optimize energy allocation by restraining excessive biomineralization in C. gigas. This study reveals the essential role of species-specific SMPs secreted via exosomes in the biomineralization adaptation and adaptive potential of mollusks in future marine environments.

Graphical Abstract

Many marine invertebrate larvae are influenced by environmental factors during development, with diatom biofilms playing a crucial role in the settlement and metamorphosis of bivalve larvae. This study found that Navicula sp. biofilms alter the larval microenvironment by increasing dissolved oxygen levels through photosynthesis and decreasing nitrate, ammonium, and phosphate levels in the surrounding water. Exposure to Navicula sp. biofilms induced directional swimming in larvae and significantly shortened the time required for settlement and metamorphosis. Biofilms formed by Navicula sp. contained effective substances and key infochemicals that promoted the settlement and metamorphosis of Mizuhopecten yessoensis larvae. Soluble polysaccharides containing β-1,4-glycosidic bonds secreted by the biofilm were recognized by the larvae, triggering settlement and metamorphosis signaling. Untargeted and targeted metabolomic analyses revealed increased levels of cGMP (Cyclic guanosine monophosphate), and GMP (Guanosine monophosphate), suggesting that larval settlement and metamorphosis may be associated with cGMP regulation. Based on these results, cGMP was selected for subsequent functional analyses. Treatments with the NO donor SNAP, the cGMP analog 8-Br-cGMP, and the sGC activator BAY 41-2272 significantly promoted metamorphosis, whereas the sGC inhibitor ODQ suppressed metamorphosis in a dose-dependent manner. These findings demonstrate that the NO–sGC–cGMP pathway positively regulates the settlement and metamorphosis of M. yessoensis larvae, with cGMP serving as a key effector. This study provides new insights into the mechanisms underlying larval settlement and metamorphosis in bivalves.

Whiteleg shrimp, Penaeus vannamei, is the most cultured shrimp species worldwide and plays an important role in global aquaculture production, food security, and economic growth. Nonetheless, infectious diseases, including acute hepatopancreatic necrosis disease (AHPND), can severely threaten the sustainability of shrimp production. These impacts may also be exacerbated by climate-related environmental stressors, such as temperature and salinity, which further disrupt host metabolism and immunity. Although many shrimp genes have been reported in AHPND studies, the molecular interactions underlying host responses to this disease remain unclear. Therefore, this study aims to investigate the potential molecular mechanisms of AHPND by identifying sets of interacting proteins and associated biological functions using network clustering. The P. vannamei AHPND-related proteins (PvAHPNDrp) were identified via bibliomic analysis and used to construct the AHPND protein-protein interaction (PPI) network. The network was clustered using the DPClusO algorithm, and statistically enriched clusters were identified using the PvAHPNDrp distribution. Functional enrichment analysis was subsequently performed to determine the potential biological functions associated with AHPND mechanisms. The analysis identified significant clusters with interactions of PvAHPNDrp and non-PvAHPNDrp, including glutamine-, proline-, and tyrosine-tRNA ligases, and alpha-1,4-N-acetylglucosaminyltransferase. Enriched biological functions, such as aminoacyl-tRNA ligase activity and lipid metabolic process, may be associated with P. vannamei’s response to AHPND. Collectively, this study provides a systems-level perspective on the molecular interaction networks associated with AHPND and identifies candidate proteins and functions for future experimental validation, contributing to improved understanding of disease mechanisms and supporting climate-resilient shrimp health management strategies.

Pseudobagrus ussuriensis is a widely cultured bagrid fish known for its delicious tastes and high nutrition values in China. As growth performances of this fish significantly declined in recent years, the breeding of new germplasm with excellent growth traits is urgently needed. In the present study, the genome-wide association study (GWAS) method was used to identify genetic sites significantly associated with five growth traits in a population with 183 individuals. A total of 2,408,557 high-quality SNPs were identified across the 26 chromosomes of the genome. Among these, 31 SNPs were found to be significantly associated with growth traits, including 12 SNPs on Chr08, Chr17 and Chr21 associated with body length, 9 SNPs from Chr07, Chr08, Chr16, Chr22 and Chr25 associated with head length, 8 SNPs on Chr03 and Chr08 associated with body weight, and 4 SNPs from Chr03, Chr04, Chr08 and Chr15 associated with condition factor. One SNP, Chr08:20667021, located at the upstream region of the pld1 gene, was significantly associated with body length, head length and body weight, and it was also validated using Sanger sequencing in 100 individuals. Within a 50 kb range upstream and downstream of the 31 significant SNPs, 71 candidate genes were identified, with 28 of them being considered as more probable growth-associated candidate genes. The results of this study showed that the majority of growth related SNPs and candidate genes clustered on Chr08, which may be dominant in the process of growth regulation. These findings provide valuable insights into the genetic mechanisms of growth and useful tools for marker-assisted selection breeding in P. ussuriensis.

Coilia nasus is a migratory fish in China, inhabiting oceanic waters and spawning in rivers and lakes, and exhibiting various ecotypes. Following a technological breakthrough in artificial breeding of this species from wild migratory form, a stock enhancement and release program was initiated to replenish its natural resources. However, comprehensive genomic comparisons among the migratory form and farmed populations remain limited. Here, we employed 2b-RAD sequencing to investigate genetic diversity of wild migratory form across marine, estuarine, migratory-route populations in comparison with the farmed populations. In total, 835 high-quality single nucleotide polymorphisms (SNPs) were detected, with the highest proportion (28.1%) located in exon regions. Significant genetic differences (P < 0.01) were observed between the farmed and wild populations, corresponding to a moderate level of differentiation based on pairwise Fst values (0.082–0.091). Population structure clearly separated the two groups: the farmed populations showed distinct genetic components, while the wild populations displayed only minor compositional differences. Phylogenetic analyses further distinguished the farmed from wild populations. Functional enrichment analyses revealed that elevated SNP frequencies in the farmed population were linked to genes related to growth, metabolism, and intestinal immunity, likely reflecting adaptation to nutrient-rich conditions and growth demands under captive environments. Additionally, 12 SNPs were validated for distinguishing farmed from wild individuals by PCR combined with sequencing. These findings provide genomic insights into the artificial breeding effects on C. nasus and offer practical tools for stock management and germplasm conservation of this ecologically important fish.

Connective tissue growth factor (ctgf) is a multifunctional protein that plays a crucial role in promoting collagen (the most abundant protein in organism) synthesis in vertebrates. However, its transcriptional regulation mechanism is poorly understood, especially in teleosts. In this study, we characterized the ctgf promoter (3,185 bp) from a marine teleost, the chu’s croaker (Nibea coibor), and elucidated its response to TGF-β1 during collagen synthesis in swim bladder cells. Bioinformatics analysis revealed conserved cis-elements (TATA box, SP-1, Smad-3, NF-κB) within the promoter. Truncation assays identified a core functional region (-785 ~ + 166 bp). Notably, site-directed mutagenesis showed that mutation of SP-1 binding site enhanced the promoter activity, while mutations in binding sites of Smad-3 (-290 bp) and NF-κB (-262 bp) suppressed its activity. To demonstrate its correlation with collagen synthesis, swim bladder cells stably transfected with ctgf promoter drived EGFP vector (pctgf-EGFP) was constructed. It was further found that the promoter activity was up-regulated in concert with collagen synthesis promoted by TGF-β1 in swim bladder cells. These findings could advance our understanding of the transcriptional regulation of ctgf, and establish a technical platform for further screening natural compounds promoting collagen synthesis in fish.

For economically viable fish species that exhibit sexual dimorphism in growth performance, such as common carp, cultivating monosex populations is an effective approach to enhance aquaculture yields. This method for producing an all-female carp population involves inducing pseudo-male carp through exogenous androgen/estrogen inhibitor administration, followed by crossing these pseudo-males with wild-type female carp to generate all-female offspring. However, the sex reversal effect induced by exogenous androgen/estrogen inhibitors is unstable, making the maintenance of these pseudo-male broodstocks a time-consuming and labor-intensive process, and posing a risk of aquatic environmental contamination. High temperatures can efficiently induce pseudo-males in Indian carp (Cyprinus carpio L). However, we achieved little success when applying the same method to Yellow River carp. In this study, we systematically tested the effects of different high-temperature treatment periods on sex reversal in Yellow River carp, a geographically distinct strain of common carp (Cyprinus carpio) endemic to the Yellow River basin in China. High-temperature treatment, before and after sexual differentiation, genetically female carp were induced to develop into phenotypically male with functional testes. Furthermore, sex-differentiated female Yellow River carp are more sensitive to high temperatures, making them more prone to reversal. Therefore, a novel method for the production of pseudo-male Yellow River carp was established by inducing secondary sex reversal through high-temperature exposure. Pseudo-male carp prepared using this method possessed a stable sperm-production capacity. Our study provides a novel strategy for cultivating all-female carp populations.