Marine Life Science & Technology最新文献

Damage to the epithelial barrier is among key processes contributing to initiation and chronic inflammation in inflammatory bowel diseases (IBD). Only management therapy exists for IBD (e.g., anti-inflammatory and immunomodulatory agents, JAK/STAT inhibitors), and while novel therapeutic approaches have shown great potential, issues remain including route of administration, development of resistance to therapy and toxicity. Thus, novel small molecule inhibitors which can alleviate colonic inflammation and restore intestinal barrier functions are needed. Our previous study identified a new quinazolinone derivative MR2938, inspired by marine natural product penipanoid C, displaying impressive anti-inflammatory effects. In vivo efficacy study indicated that MR2938 had a dose-dependent effect on improving colitis symptoms, gut-barrier disruption, and colonic inflammation in an acute dextran sulfate sodium (DSS)-induced murine colitis as a model of epithelial injury relevant to IBD. Evaluation of potential mechanism involved in MR2938 efficacy demonstrated that MR2938 inhibited NF-κB-mediated inflammatory responses, and attenuated intestinal epithelial tight junction damage by restoring the expression of Occludin and ZO-1. Taken together, these data suggest that MR2938 is a promising lead compound for the treatment of IBD.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-025-00285-x.

As dynamic and functionally active organelles, lipid droplets (LDs) mainly function in lipid anabolism, while recent studies showed that mammalian LDs also actively participated in innate immunity; however, the specific roles and regulation mechanism remain relatively unexplored, and the existing studies were mainly limited to mammals. In the present study, we first found that Vibrio harveyi, a serious pathogen in marine environment, could induce LDs accumulation in the liver of obscure puffer Takifugu obscurus on the histology, morphology and molecular levels, and the induction mainly conducted by promoting the synthesis of neutral lipids. Moreover, the antibacterial activity of LD proteins was significantly enhanced upon V. harveyi stimulation, and showed broad-spectrum characteristic. While the inhibition of LDs formation downregulated the expression of immune-related genes and immune signaling elements, highlighting the potential critical roles of LDs during the bacterial infection. The isolated LDs from obscure puffer liver were examined via proteomic analyses, and the data supported the conservative property of LDs from bacteria to humans, and revealed that numerous innate immune system-related components were enriched on the surface of LDs. These results will deepen the understanding of LDs biology and host immune defense mechanism, shedding light on the new strategies for the development of anti-infective therapies.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-025-00286-w.

Astome ciliates live in the digestive tract of a broad spectrum of marine, freshwater, and terricolous annelids. In aquatic lumbriculid and criodrilid oligochaetes collected in Central Europe, we rediscovered three insufficiently known astomes: Hoplitophrya secans, Mesnilella clavata, and Buchneriella criodrili. Their morphology was studied using in vivo observation, protargol, and dry silver nitrate impregnation. Multiple nuclear and mitochondrial molecular markers were used to determine their phylogenetic positions and reconstruct their evolutionary history. According to our phylogenetic analyses: (1) mouthless ciliates isolated from annelids form a robustly supported monophylum within the class Oligohymenophorea, (2) the progenitor of astomes invaded the digestive tract of marine polychaetes during the Paleozoic era, (3) lumbricid earthworms likely served as a source of astomes for criodrilid, almid, and megascolecid earthworms, (4) the ancestral host of the earthworm-dwelling astome clade led an endogeic lifestyle, and (5) there were multiple independent transfers of astomes from endogeic to epigeic and anecic earthworms. These findings support previous views of the annelid phylogeny, suggesting that astomes reside and evolve in tandem with annelids for several hundred million years.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00275-5.

Annual bay scallops are commercially significant bivalve species for fisheries and aquaculture, but their small size and severe inbreeding depression impede the development of their industry. Some interspecific hybrids of bay scallops and peruvian scallops show longer lifespans and significantly greater sizes, which may result from the longevity genes in the latter (7-10 years). Sirtuins (SIRTs) play pivotal roles in the genetic control of aging in various model species and human beings. However, the role of SIRTs in longevity has not been systematically studied in aquatic animals. In this study, different gene numbers, sequences, structures and tandem duplications of SIRTs were first identified between the two scallops through genome-wide analysis. Cloning and characteristics of the SIRT1 and SIRT6 ORFs revealed dramatic variations in amino acids between the two scallops, which may cause intrinsic differences in function for longevity regulation. In particular, the amino acid variations in the N-terminus may auto-regulate conformations, causing intrinsic differences in catalytic activity for longevity regulation. The robust expression of SIRT1 and SIRT6-2 in peruvian scallops suggested they may exert a role in extending the lifespan. Nutrient restriction (NR) could promote lifespan in terrestrial model organisms, and the SIRTs and their related genes responded to NR for longevity in scallops; peruvian scallops showed a higher ability of autophagy. This study provides potential biomarkers for breeding long-lived larger scallop hybrids for the sustainability of aquaculture. Moreover, the genetic variation during evolution in the two scallops provides a foundation for further research on the longevity function of the SIRTs.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00269-3.

Microbial degradation of methylphosphonate (MPn) is an important pathway contributing to the 'methane paradox' in the oxic ocean. Vibrio spp. are suggested to participate in this process. However, little is known about the molecular basis, phylogenetic breadth and catabolic efficiency of methane production in Vibrio species. Here, 18 Vibrionales strains known to be effective in MPn demethylation were obtained. The most effective strains, i.e., Vibrio gallaecicus HW2-07 and HW2-08, can convert 70%-80% of amended MPn into methane in 5 days. Estimations based on quantitative PCR determination indicated that Vibrio spp. were influential contributors to marine methane production. Genes flanking the common phn genes suggested a divergent gene arrangement and grouped the phn operons into nine types. This was consistent with the phylogeny of phnJ and phnL. The phn operons of cluster I and II were identified frequently in Vibrio isolates and were common in coastal seas and the open ocean. Addition of MPn increased expression of the phn genes, as well as an unexpected gene that encodes an acyltransferase (act), which frequently occurred in cluster I-IV operons. This study provided experimental evidence and theoretical support for a further understanding that Vibrio spp. may play important roles in aerobic marine methane production.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-025-00278-w.

This study demonstrated the design of whey protein isolate (WPI)-mannose (Man) conjugates with triphenylphosphonium bromide (TPP) through self-assembly to prepare macrophage and mitochondrion dual-targeting astaxanthin (AXT) nanoparticles (AXT@TPP-WPI-Man). The nanoparticles displayed spherical structures with a well-dispersed size of approximately 206.1 ± 39.2 nm, with good biocompatibility, stability, and targeting capabilities. In vitro experiments demonstrated the specific accumulation of AXT@TPP-WPI-Man in mitochondria and exhibited good targeting ability toward macrophages. The AXT@TPP-WPI-Man effectively reduced reactive oxygen species and preserved the normal mitochondrial membrane potential. The AXT@TPP-WPI-Man treated ulcerative colitis mice exhibited a 52.32% increase in colon length with significant improvement in weight loss, disease activity index scores, and reduced release of inflammatory cytokines. Immunofluorescence staining indicated AXT@TPP-WPI-Man alleviated ulcerative colitis by reducing M1 polarization in colonic macrophages while promoting M2 polarization. The dual-targeting AXT@TPP-WPI-Man has the potential to improve astaxanthin bioavailability, presenting a promising delivery method for the treatment of ulcerative colitis.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00255-9.

Growth of the Pacific white shrimp Litopenaeus vannamei, the most important farmed crustacean, has consistently been a focal point for breeders. Over the past decades, some candidate genes for shrimp growth have been identified. However, further research is needed to elucidate the molecular regulatory mechanism of these genes. LvMmd2 was previously identified as a candidate gene that may inhibit the growth of L. vannamei. In this study, we analyzed the genotype and expression of the LvMmd2 gene in a breeding family and indicated its role as a growth-inhibiting gene. We found that LvMmd2 co-localized with its homolog LvPAQR3 at the Golgi apparatus. Using co-immunoprecipitation (Co-IP) and DUAL membrane system yeast two-hybrid (MbY2H), we indicated the interactions between LvMmd2 and LvPAQR3, LvPAQR3 and LvRaf1, as well as LvMmd2 and LvRho. These results suggest that LvMmd2 directly and indirectly regulates the Ras signaling pathway. Furthermore, we show that the LvMmd2 gene may indirectly affect the PI3K/AKT, insulin, and Hippo signaling pathways to regulate cell proliferation and differentiation via LvPAQR3 and LvRaf1. Through transcriptome and MbY2H analyses, we have also revealed the interaction between LvMmd2 and proteins involved in growth, immunity, protein transport, synthesis, and modification. These findings demonstrate the various molecular pathways through which LvMmd2 regulates L. vannamei growth. This study provides insights into the mechanism of shrimp growth regulated by Mmd2, enhances our understanding of LvMmd2 function, and highlights its potential application in shrimp breeding.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00273-7.

In this study, we investigated the molecular recognition mechanisms of shark-derived single-domain antibodies (ssdAbs) targeting fluoroquinolones using an integrated approach that combines in silico homologous modeling, molecular dynamics simulations, molecular docking, and alanine scanning mutagenesis. Three ssdAbs-2E6, 1N9, and 1O17-specific to enrofloxacin, norfloxacin, and ofloxacin, respectively, were selected based on previous work. Through AlphaFold2 and GalaxyWEB, the protein structures of these ssdAbs were predicted and optimized, followed by molecular dynamics simulations to emulate realistic protein behavior in a solvent environment. Molecular docking, alanine scanning mutagenesis, and subsequent verifications identified 30N and 93W of 2E6; 30N, 89R, 98Y, and 99D of 1N9; 100W and 101R of 1O17, all located within the complementarity determining region 3 loop, as critical for antigen binding. These residues primarily interact with their targets through hydrogen bonds, salt bridges, π-π stackings, and cation-π interactions. This study revealed, for the first time, the binding mechanism of ssdAbs to fluoroquinolones from a theoretical perspective, emphasizing the importance of aromatic and polar residues in recognizing characteristic epitopes, such as the carboxyl group at the C3 position and the 1-piperazinyl group at the C7 position. Our findings provide valuable insights for the rational design and enhancement of ssdAbs for detecting small molecule hazards in aquaculture.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00277-3.

Antarctic krill Euphausia superba, one of the most abundant species on the planet, is a keystone species of the Southern Ocean ecosystem. In the present study, we analyzed the RNA virome of Antarctic krill via metatranscription methods. The results showed that only 0.39% (49/12, 558) of the resultant unigenes could be assigned to known viral taxa, which were most similar to 17 known viruses, including nine invertebrate viruses, two vertebrate viruses, three protozoan viruses and three mycoviruses. However, most of the detected viruses possessed low amino acid similarity with counterparts in the viral databases. Penaeus vannamei picornavirus (PvPV; Family Picornaviridae) and covert mortality nodavirus (CMNV; Family Nodaviridae) were the two most abundant viruses in the Antarctic krill RNA virome. Notably, PvPV and CMNV are known pathogens to multiple aquatic animals according to epidemiological survey and exposure experiments, whereby PvPV positive krill caused clinical symptoms and histopathological lesions to P. vannamei and similarly, CMNV infection altered the swimming and feeding behavior of parent marine medaka Oryzias melastigma and caused tissue damage and even spinal curvature of the offspring. Results herein reveal, for the first time, the high abundance and taxonomic diversity of viruses in Antarctic krill while simultaneously highlighting the risk of an important virus reservoir to global aquaculture, and the potential impact on animals in the Antarctic ecosystem.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00270-w.

Declining populations and bottlenecks lead to the accumulation of deleterious mutations in fish populations. These processes also trigger genetic purging, which is a key genetic factor in reducing the deleterious burdens and increasing population viability. However, there is a lack of empirical evidence on the interaction between demographic history and the genome-wide pattern of deleterious variations. Here, we generated genome resequencing data of Eleutheronema rhadinum from China and Thailand, representing the major distribution of the species' southern regions. E. rhadinum had exceptionally low genome-wide variability and experienced dramatic population expansions followed by continuous declines. The geographical divergence, which occurred ~ 23,000 years ago, shaped different demographic trajectories and generated different regional patterns of deleterious mutations in China and Thailand populations. Several lines of evidence revealed that this geographical pattern of deleterious mutation was driven by the purging of highly deleterious mutations. We showed that purifying selection had inbreeding-associated fitness costs and was more efficient against missense mutations in the Thailand population, which had the lowest genetic burden of homozygous deleterious mutations. Multiple evolutionarily conserved protein domains were disrupted by the loss-of-function mutations, posing a high probability of gene functionality elimination. Moreover, thermal and salinity genes (Trpm3, Nek4, Gtf2f2, Cldn14) were identified in genomic divergence regions of E. rhadinum among China and Thailand populations. Our findings highlight the importance of demographic history factors shaping the geographical patterns of deleterious mutations. The results serve to deepen our understanding of the adaptive evolution and divergence of E. rhadinum with implications for other marine fish.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-024-00276-4.