Ciliated protists (ciliates) represent a morphologically and genetically diverse group of single-celled eukaryotes, the phylogeny of which is critical for understanding eukaryotic evolution. Through international collaborations, the Laboratory of Protozoology at Ocean University of China (OUC-group) has conducted detailed research on ciliate phylogeny based on expanded taxonomic sampling, employing single gene as well as multi-gene markers, and phylogenomic datasets. We have systematically investigated>1000 ciliate species spanning~40 orders, sampled from diverse biotopes including marine environments in China seas and freshwater wetlands. This comprehensive sampling has generated three key datasets: (1) genomic DNA extracts from~2600 strains, (2)~2300 sequences of marker genes, and (3) single-cell genomic and/or transcriptomic datasets from~120 species. Based on these datasets, the phylogenetic relationships covering all classes and most orders have been thoroughly reconstructed and investigated, resulting in the establishment of 93 new supraspecies taxa comprising two classes (Mesodiniea and Protocruziea), two subclasses (Protohypotrichia and Synhymenia), two orders (Wilbertomorphida and Lynnellida), 11 families, and 76 genera. Moreover, we have reconstructed a genome-scale tree of life for ciliates and provided an updated classification of the phylum Ciliophora. Furthermore, based on the robust phylogenetic tree of ciliates, we provide more reliable estimates for the origins and divergence times of the main ciliate groups. Future studies integrating advanced genomics, innovations in culturing and interdisciplinary applications will refine the ciliate tree of life, with broader impacts for our understanding of eukaryotic evolution and biodiversity.

Anammox and denitrification are key processes for nitrogen removal in lake sediments. However, how environmental changes mediate the community structure and functional genes of nitrogen removal bacteria in lakes remain unclear. Using metagenome and amplicon sequencing, we investigated the anammox and denitrifying bacteria and their nitrogen removing potentials in lakes experiencing significant spatiotemporal and environmental variations. The community structure of anammox and denitrifying bacteria exhibited stronger lake-wide spatial variations than that of seasonality, while only the denitrification-related functional genes showed substantial variations in both lakes. Anammox genes (e.g., hzsA/B/C and hdh) showed no significant spatial variations. However, the abundances of anammox and denitrifying genes were significantly higher in winter than in summer. The mesotrophic Lake Weishan demonstrated a greater capacity for complete denitrification in winter, while the eutrophic Lake Donghu exhibited a higher potential of anammox in summer. Differences in functional gene abundances between lakes were more pronounced than variations in phylogenetic diversity, indicating clear functional adaptations to local environments. The coupled nitrogen removal potentials also reflected ecological interactions among anammox and denitrifying genes. Importantly, anammox and denitrifying bacterial communities and their functional genes were primarily driven by dissolved organic carbon, total phosphorous and zinc (Zn). The dissimilarities of anammox and denitrifying bacterial communities increased with geographic distance, indicating a clear distance-decay effect. This study highlights the anammox and denitrifying bacteria and their nitrogen removal potentials in lake sediments that are mediated by both spatial and seasonal environmental changes.

Ciliates in the order Metopida exhibit a global distribution and play essential roles as consumers of and common hosts to prokaryotes in both hypoxic and anoxic environments. Based on detailed morphological and morphometric data of Metopus es and Brachonella contorta, type species of two common and relatively species-rich metopid genera, we investigate the morphogenesis, and molecular phylogeny of each, and analyze the secondary structure of the V9 region of their 18S rRNA gene sequences. The new findings include: (1) These two species present two different stomatogenetic modes, which are stable within their respective genera and each can be regarded as a reliable generic feature for differentiation. (2) Both species share the same outcome regarding the parental oral apparatus, i.e., the old paroral membrane and adoral zone of membranelles are entirely reorganized in situ in the proter. (3) The paroral membrane is diplostichomonadal in the examined isolates, a feature which has long been overlooked and may be enigmatically present in other previously described populations. As concerns their phylogeny, the clear delineation of each species is supported by the high conservation of SSU rRNA gene sequences, and the close phylogenetic clustering, of different populations of each species from geographically distant localities. In agreement with previous phylogenetic studies, the MeBr clade (Metopus, including M. es and marine/brackish Metopus members, and all Brachonella species) is recovered repeatedly with moderate to high support.

Methanogenic endosymbionts are the only known intracellular archaeans and are especially common in anaerobic ciliated protists. Studies on the evolution of associations between anaerobic ciliates and their methanogenic endosymbionts offer an excellent opportunity to broaden our knowledge about symbiosis theory and adaptation of eukaryotes to anoxic environments. Here, the diversity of methanogenic endosymbionts was analyzed with the addition of nine anaerobic ciliate populations that were newly studied by various methods. Results showed that diverse anaerobic ciliates host methanogenic endosymbionts that are limited to a few genera in orders Methanomicrobiales, Methanobacteriales, and Methanosarcinales. For the first time, anaerobic ciliates of the classes Muranotrichea and Prostomatea were found to host methanogenic endosymbionts. Distinct origins of endosymbiosis were revealed for classes Armophorea and Plagiopylea. We posit that armophoreans and plagiopyleans might have harbored Methanoregula (order Methanomicrobiales) and Methanocorpusculum (order Methanomicrobiales), respectively, as methanogenic endosymbionts at the beginning of their evolution. Subsequently, independent endosymbiont replacement events occurred in methanogen-ciliate associations, probably due to ecological transitions, species radiation of ciliate hosts, and vertical transmission bottlenecks of endosymbionts. Our results shed light on the evolution of associations between anaerobic ciliates and methanogens, and identifies the necessary preconditions for illustrating mechanisms by which endosymbioses between these partners were established.

Red alga species in the phylum Rhodophyta are ecologically and economically important, which are widely used as food and medicinal products because they are rich in bioactive compounds. Unfortunately, researchers often meet challenges in identifying red algal species and understanding the evolutionary relationship among them. Shooting away these limitations necessitates detailed genomic studies, including those of cellular organelles. In this study, we sequenced circular organelle genomes of three red macroalgal species, Grateloupia asiatica, Pachymeniopsis lanceolata and Polyopes affinis, yielding two complete chloroplast genomes of P. lanceolata and P. affinis and one mitochondrial genome of P. affinis. The average chloroplast and mitochondrial genome sizes were 192,724 bp and 29,699 bp, respectively, which encoded 202 and 25 proteins, respectively, on average. The short- and long-repeat sequences, gene rearrangements, the nucleotide diversity, and phylogenetic relationship among these three species were analyzed. Memo: revise conjunctions and prepositions to form a clearer list (A, B, C, and D). The 194 chloroplast and 23 mitochondrial protein-coding genes shared by the species belonging to Florideophyceae and Bangiophyceae were used to reconstruct a maximum-likelihood phylogenetic tree. In addition, we developed 15 species-specific PCR markers, five for each species, using single-nucleotide polymorphism information. Our results should aid in identifying these species and deciphering the evolutionary relationship among species in the phylum Rhodophyta.

Urochordate Ciona spp. are ideal marine model organisms for studying embryogenesis and developmental and evolutionary biology. However, the effective implementation of genetic labeling and CRISPR/Cas9-based editing tools at cellular resolution remains challenging. This study successfully developed and validated a collection of Gateway-based vectors for cell labeling in Ciona spp. The destination vector sets contained two Gateway cassettes flanked by Minos sites, allowing the N- or C-terminal tagging of a protein of interest with various fluorescent markers. In addition, we optimized the CRISPR/Cas9 and CRISPR/dCas9 systems by incorporating P2A-mCherry, a fluorescent indicator for Cas9 expression at cellular resolution. We demonstrated the effective destruction or inhibition of target genes when CRISPR constructs were introduced into fertilized eggs. Furthermore, we engineered a dual fluorescence sensor system that helps visualize successful gene knockouts at the cellular level in specific tissues. The genetic tools developed in this study offer a robust method for gene expression, cell tracking, and subcellular protein localization while also facilitating tissue-specific functional analysis in Ciona embryos and other model systems.

Aurelia aurita exhibits a triphasic life cycle involving metamorphosis, transitioning from sessile polyps to free-swimming ephyrae and eventually maturing into medusae. This metamorphic process is triggered by a reduction in temperature. In this investigation, we delve into the intricate changes in protein, lipid, and carbohydrate content, and examine alterations in respiratory and excretory metabolisms using both physiological and enzymatic methodologies. This study provides the first monitoring of these parameters. Observations at compositional and metabolic levels were conducted over 108 days in triplicate, with three simultaneous cultures maintained under identical conditions throughout the experiment. The findings reveal compositional changes, particularly in lipid content, one of the main sources of biological energy during metamorphosis. Additionally, a 20-day increase in water content from 89 to 99% occurred during the transition from strobila to metaephyra. Respiratory activity reduced by 76% during strobilation, due to the necessary temperature drop. Concurrently, excretory activity showed a more gradual increase in ammonium excretion during the planktonic stages once feeding resumed. These findings highlight the role of temperature-dependent triggers and metabolic shifts in facilitating energy storage among other functions. This knowledge may provide insights into the potential impacts of future environmental change on the entire lifecycle.

The complex current systems of the Southern Ocean play a critical role in shaping the heterogeneity and distinctiveness of Antarctic habitats. Nonetheless, how Antarctic water masses influence ciliates, one of the most common groups of protozoa in polar regions, remains largely unknown. The present study investigated how the ciliate communities are affected by complex Southern Ocean currents by analyzing the diversity distributions, community assembly mechanisms, and co-occurrence networks of ciliates across three distinct water masses in the Scotia Sea. The findings reveal that the hydrography of the Scotia Sea significantly affects the spatial patterns of planktonic ciliates, primarily through the combination of temperature, salinity, and depth. In contract to surface waters (Antarctic Surface Water and Antarctic Circumpolar Current), ciliates inhabiting deep waters (Circumpolar Deep Water) exhibit stronger and more direct correlations with the environment parameters, alongside greater network stability. Community assembly in surface and deep-water masses is governed by stochastic and deterministic processes, respectively. Compared to other Antarctic regions documented in previous studies, the Scotia Sea demonstrated the lowest alpha diversity indices for ciliates while harboring the highest number of endemic species. A detailed re-evaluation of Antarctic ciliate community structure in the Antarctic from prior research offers valuable insights into how dynamic ocean currents shape the ecological dynamics of ciliate communities, thus providing a broader understanding of the environmental changes impacting polar marine ecosystems.

Glucocorticoids, crucial regulatory hormones involved in the stress response, significantly influence growth, development, and metabolism through activation of the glucocorticoid receptor (GR). Hypoxia-inducible factor 3 alpha (HIF-3α), the least characterized paralog among three HIF-α proteins, plays a role in adaptation to oxygen level changes and metabolic reprogramming. Despite the potential functional overlaps between GR and HIF-3α pathways in regulating metabolism, their crosstalk remains poorly understood. Here, we demonstrate a regulatory mechanism governing the crosstalk between these two transcription factor pathways. We found that upon ligand activation, GR binds to the intronic region of the HIF3A gene and upregulates its mRNA transcription. Additionally, HIF-3α and GR engage in protein–protein interactions through the oxygen-dependent degradation domain of HIF-3α and all major domains of GR (i.e. the N-terminal, DNA-binding, and ligand-binding domains). Furthermore, we discovered that this interaction results in reciprocal attenuation of the transcriptional activities of both GR and HIF-3α, causing a negative feedback loop upon HIF3A gene expression. The GR-HIF-3α interaction may offer a targetable pivot to modulate these two TF pathways, potentially providing a novel therapeutic avenue for related diseases.

Our study introduces scITDG, a tool designed for the analysis of time-dependent gene expression in single-cell transcriptomic sequencing data, effectively filling a gap in current analytical resources. A key advantage of scITDG is its ability to identify dynamic gene expression patterns across multiple time points at single-cell resolution, which is pivotal for deciphering complex biological processes such as aging and tissue regeneration. The tool is compatible with widely used single-cell analysis platforms such as Seurat and Scanpy. By integrating natural cubic splines regression with bootstrapping resampling, scITDG enhances the functionality of these platforms and broadens their applicability. In this study, based on scITDG, we revealed intricate gene expression modules in mice aging and axolotl limb regeneration, providing valuable insights into cellular function and response mechanisms. The versatility of scITDG makes it applicable to a wide range of biological contexts, including development, circadian rhythms, disease progression, and therapeutic responses.

Natural products are effective in the treatment and the prevention of human, animal and plant diseases. Therefore, natural products may also be considered to treat fish diseases. Acori Tatarinowii Rhizoma (ATR) is a herbal medicine with anti-inflammatory and antioxidant effects. However, little is known about how its active ingredients exert the beneficial effects. Here, Four effective active ingredients of ATR and their 81 targets were investigated, which affected the anti-inflammatory response. Among them, kaempferol-JUN was identified as a key regulatory module in anti-inflammatory immune responses, and kaempferol interacted with the CiJUN protein and inhibited CiJUN levels. Silencing CiJUN gene in Ctenopharyngodon idella kidney (CIK) cells enhanced anti-inflammatory activity and resistance to Aeromonas hydrophila, whereas anti-inflammatory activity and resistance were impaired after CiJUN overexpression. The mortality rate of diseased grass carp was reduced after treatment with kaempferol, as were the inflammatory and oxidant effects. Also, grass carp showed enhanced anti-inflammatory and antioxidant effects after feeding with kaempferol. The results provide further insights into the use of kaempferol to prevent and treat fish diseases.

High-glucose environments induce cellular stress, particularly endoplasmic reticulum stress (ERS) and oxidative stress, in aquatic animals. Taurine, known for its cell-protective properties, has potential in mitigating such stress. This study investigated taurine’s effects on ERS, oxidative stress, apoptosis, and glycogen accumulation in golden pompano (Trachinotus ovatus) muscle cells under high-glucose conditions. Cells were cultured with varying glucose concentrations and taurine supplementation. Techniques including Cell Counting Kit-8 (CCK-8) assay, Nile Red staining, periodic acid–Schiff (PAS) staining, and transmission electron microscopy (TEM) were used to assess cell viability, lipid deposition, glycogen accumulation, and ultrastructural changes, respectively. High glucose increased the ADP/ATP ratio, reactive oxygen species (ROS) levels, and reduced mitochondrial membrane potential (MMP), activating AMP-activated protein kinase (AMPK). This led to glycogen accumulation via increased glycogen synthase (gysm) expression and decreased glycogen phosphorylase (pygm) expression. Taurine supplementation restored glycogen balance, reduced glucose transporter 4 (GLUT4) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) protein levels, and alleviated ERS, as evidenced by reduced PKR-like ER kinase (perk) mRNA and glucose-regulated protein 78 (GRP78) protein expression. Also, taurine improved mitochondrial function, inhibiting apoptosis by reducing cytochrome C (CytC) release. In conclusion, taurine alleviated ERS, glycogen accumulation, apoptosis, and mitochondrial oxidative stress, providing new insights into taurine’s mechanisms and supporting its potential use as a feed additive in aquaculture.

To promote sustainable aquaculture, plant-based ingredients are increasingly replacing fish meal (FM) and fish oil (FO) in aquafeeds, altering broodstock diets and reducing omega-3 long-chain polyunsaturated fatty acids (ω-3 LC-PUFAs), essential for reproductive success and progeny growth. Despite the critical role of ω-3 LC-PUFAs, particularly docosahexaenoic acid (DHA) in brain function, data on how fry cope with FM/FO-free diets during early development remain limited. To address this, we conducted a 2-year experiment comparing three broodstock diets: a commercial diet (C diet), a total plant-based diet (V1 diet), and a plant-based diet supplemented with DHA-rich Schizochytrium sp. microalgae oil (V2 diet). After reproduction, progeny were fed either a C diet or a plant-based diet (V). Six groups (C–C, C–V, V1–C, V1–V, V2–C, V2–V) were analyzed for survival, feed intake, and growth, as well as neuropeptide, neurotransmitter, and intestinal hormone expression. Results showed enhanced robustness in fry-fed V diets, particularly from V1 and V2-fed broodstock, with improved survival and feed intake. Fry from DHA-supplemented broodstock (V2–V) compensated for initial growth delays, achieving growth comparable to fry from commercial-fed mothers (C–V) within 30 days. Neurophysiological and gut–brain adaptations revealed complex compensatory mechanisms enabling fish to thrive on sustainable diets. These findings highlight the potential of DHA supplementation in plant-based diets to support sustainable aquaculture and warrant further validation under diverse nutritional and environmental conditions.

Post-translational modifications (PTMs) regulate the activity and functionality of RELA, but their role in the pathogenesis of liver fibrosis is unclear. This study was performed to understand the regulation mechanism of acetylation of RELA on liver inflammation and fibrosis in a model animal of innate glucose intolerance, largemouth bass, and to provide a potential target and biomarker for liver fibrosis therapy. We found that the acetylation of total proteins and RELA was significantly reduced in fibrotic livers of largemouth bass induced by a high-carbohydrate and high-fat diet (HCHFD) and CCL4 challenge. Furthermore, quantitative acetylome data showed that the K119 site of RELA was deacetylated in fibrotic livers compared to healthy controls. Subsequently, we reveal a new mechanism that SIRT7 deacetylates RELA at the K119 site in largemouth bass. RELA K119 deacetylation enhances RELA transcriptional activity by increasing its DNA-binding activity, and facilitates nuclear translocation of RELA, resulting in the overwhelming release of proinflammatory factors, and subsequently enhancing liver inflammation and fibrosis. Pharmacological inhibition of SIRT7 using a specific inhibitor restores the decreased acetylation of RELA in vivo and in vitro, and reduces the transcriptional activity, nuclear localization of RELA and the expression of its target genes, which ultimately attenuates liver inflammation and fibrosis. These findings uncover a novel mechanism underlying liver fibrosis involving SIRT7-mediated deacetylation of RELA to activate the proinflammatory gene program, and thus provide important insights and biomarkers into the effective strategies for limiting liver inflammation and fibrosis.

Temperature is well known as the major environmental factor that influences survival and growth of fish, which are poikilothermic animals. However, it is still unclear about the mechanism that underscores thermal-controlled fish physiology, especially nutritional utilization and metabolism, which are vitally important in aquaculture. In the present study, juvenile turbot was force-fed with amino acid mixture and its postprandial absorption, nutrient sensing and metabolism under low (12, 15 ℃), optimal (18 ℃) to high (21, 24 ℃) temperatures were explored. Intestinal trypsin and lipase activity were highly sensitive to water temperature, and highest under optimal temperatures for turbot, whereas amylase remained constant. Selective groups of intestinal amino acid transporters were upregulated in cold temperatures, but the amino acid absorption capability was increased with rising temperature. The mechanistic target of rapamycin (mTOR) signaling pathway was most active at optimal temperature. Postprandial muscle protein deposition achieved maximum level under optimal temperature. Amino acid catabolic enzymes branched-chain aminotransferase and branched-chain α-keto acid dehydrogenase activities were increased with rising temperatures. High temperature increased significantly energy metabolism and stimulated cellular stress in liver. These findings highlight the critical role of temperature in modulating amino acid dynamics, metabolic processes and stress responses in juvenile turbot, providing valuable insights for optimizing aquaculture practices.

Although anisotropic NMR spectroscopy has emerged as a powerful method for determining the relative configuration of complex natural products, major challenges persist with structurally flexible molecules. In this study, we conducted a systematic comparative analysis of stereochemical elucidation, combining anisotropic NMR spectroscopy and density functional theory (DFT) calculations on spiroepicoccin B (1) and epicoccin V (2), which were characterized as thiodiketopiperazine marine natural products isolated from the deep-sea-derived fungus Epicoccum nigrum SD-388. For the flexible compound 2, we compared various conformational sampling approaches, including an assessment of the quality of relative energies within the obtained ensembles. We demonstrated the critical role of dispersion correction within DFT computations to precisely account for weak non-bonded intramolecular interactions. By integrating anisotropic NMR analysis, chemical shifts, electronic circular dichroism, and DFT computations, we determined the absolute configurations and conformational ensembles for 1 and 2, respectively, highlighting the significance of the intramolecular methyl–π interaction in stabilizing one of the conformers. Our study introduces new strategies to address conformational flexibility in the stereochemical elucidation of challenging organic molecules.

Seven previously unreported sesquiterpenes including three rare 5/5/6-fused tricyclic gymnomitrane-type sesquiterpenes (1–3), an ent-longipinane-type sesquiterpene (4), a cuparane-type sesquiterpene (5), and two chamigrane-type sesquiterpenes (6 and 7), along with a known chamigrane-type sesquiterpene xylariterpenoid C (8) were isolated from the hydrothermal vent sediment derived fungus Penicillium sp. JWM79-5–1. Their structures were identified on the basis of 1D and 2D NMR, in conjunction with Mosher’s method, X-ray crystallography, and electronic circular dichroism (ECD). The antithrombotic activity of compounds 1–6 and 8 was evaluated in arachidonic acid (AA)-induced zebrafish thrombosis model in vivo. The results revealed compound 1 with potent antithrombotic activity in a concentration-dependent manner. Further, the pro-angiogenic activities of compounds 1–6 and 8 were evaluated in a transgenic zebrafish model that expresses vegfr2, the receptor for the angiogenic factor VEGF, tagged with the green fluorescence protein (vegfr2-GFP) through detecting the length of both intersegmental vessels (ISVs) and subintestinal veins (SIVs). The results revealed that compound 1 exhibited a potent antithrombotic activity while 3 revealed a potent pro-angiogenic activity. These findings strongly support drug development of these compounds in cardiovascular disease treatment.

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.

Phenazine derivatives, a class of naturally occurring antibiotics primarily produced by bacteria, are regarded as promising scaffolds for developing new antibiotics. In this study, eight new dimeric phenazine derivatives, phenazostains K‒R (1‒8), along with two reported dimeric analogues, phenazostains B (9) and C (10), were isolated from the fermentation broth of the marine-derived Streptomyces sp. OUCMDZ-4923. Their structures were elucidated through spectroscopic analysis, primarily using NMR and HRESIMS spectra, ECD calculations, and the modified Mosher’s method. Compounds 1‒10 feature the 12-deoxysaphenate unit linked to various sites on methyl saphenate, phenazine, or methyl phenazine-1-carboxylate. Notably, compounds 1 and 2 represent the first dimeric phenazines linked by a 12,12'-oxy bridge. Our experimental results suggest that these dimers could be formed from methyl saphenate (12) through a nonenzymatic pathway. Moreover, the analysis of gene roles within their biosynthetic gene cluster revealed that phenazostains 1‒8 are formed through a nonenzymatic process. Additionally, all dimers were evaluated for their antibacterial activity; compounds 1, 3‒5, and 9 exhibited inhibitory activities against both Staphylococcus aureus and its methicillin-resistant strain (MRSA), with MIC values ranging from 1.56 to 25.0 μg/mL.

Analysis of the secondary metabolite biosynthesis gene cluster (BGC) from marine Streptomyces sp. SNJ102 revealed the presence of a noncanonical nonribosomal peptide synthetase (NRPS), predicted to produce a depsipeptide compound. The NRPS gene cluster was captured by transformation-associated recombination and heterologously expressed in Streptomyces albus. The production of the new compound was confirmed using high-resolution liquid chromatography-mass spectrometry, and its structure was elucidated using nuclear magnetic resonance spectroscopy. The structure of the new depsipeptide was more similar to the monomeric structure of cyclic depsipeptides derived from fungi than to other Streptomyces-derived depsipeptides. In addition, the bacterial depsipeptide, which we named jejumide, showed promising anti-inflammatory activity. These results demonstrate that genome mining and successful heterologous expression of cryptic nonlinear NRPS BGCs from marine bacteria will facilitate the discovery of novel nonribosomal peptides and understanding of the complicated biosynthetic mechanism of nonlinear NRPS.

Small cell lung cancer (SCLC) is a high-grade malignancy and prone to drug resistance, with limited progress in patient survival over the past 30 years. Therefore, there is an urgent need to explore new treatment strategies for SCLC patients. Autophagic cell death represents a novel therapeutic strategy for cancer cells with high apoptotic thresholds. Here, we demonstrate that nitrobenzoyl-insulicolide A (1), a new sesquiterpene, isolated from Antarctica sponge-derived fungus Aspergillus insulicola HDN151418, inhibits the proliferation of various SCLC cells including adriamycin- or cisplatin/etoposide-resistant cells, via autophagic death rather than apoptosis, necrosis and cell aging. Molecular mechanism analysis revealed that compound 1 induced autophagic cell death in the NCI-H446 and H69 AR cells dependent on activations of the AKT/mTOR/PARP and ERK1/2 signaling pathways. These findings provide an experimental basis for the further development of 1 as a lead compound against small cell lung cancer in future.

Hardness is widely regarded as a critical factor influencing the whole texture of fish flesh. The objective of this study was to elucidate the regulatory mechanism underlying muscle hardness in hybrid bream (BBTB, Megalobrama amblycephala ♀×Culter alburnus ♂). A comparison of the physiological features of high hardness (HH) and low hardness (LH) muscle revealed that the former had higher contents of collagen I and lower muscle fiber diameter. Transcriptomic data revealed that the myofiber assembly pathway and the HIF-1 signaling pathway were activated in HH muscle. At the metabolic level, the categories of amino acids and lipids were the principal differentially abundant metabolites between the HH and LH muscle. The detection of amino acid profiles further revealed significant differences in amino acid metabolism between the HH and LH muscles, with the HH muscle having higher levels of amino acids than the LH muscle, especially hydroxyproline (Hyp). Furthermore, through supplementation of Hyp in BBTB myoblasts, the results indicated that 0.8 mmol/L Hyp increased the proliferation, differentiation, migration, and collagen synthesis of myoblasts. Finally, BBTB was treated with Hyp intraperitoneally for 15 days. The results revealed that 0.1 g/kg Hyp significantly increased muscle hardness, myofiber density, myofibrillar protein synthesis, and HIF-1 protein content. The results obtained in this study indicated that Hyp supplementation promoted collagen synthesis and proliferation of myoblast and muscle fibers in the BBTB, which may be induced by activation of the transcription factor HIF1 and contributes to the impacts of Hyp on improvements in muscle hardness in the BBTB.

Inexpressible Island is a small rocky island in Terra Nova Bay, Victoria Land, Antarctica, which is an area with limited human activities. Understanding the distribution of antibiotic-resistance genes (ARGs) and virulence factor genes (VFGs) in this environment can provide key information on their potential risks to humans and their roles for microbial survival. In this study, we investigated the ARGs and VFGs in lake sediments from Inexpressible Island using metagenomic sequencing. We identified 11,502,071 open-reading frames (ORFs), with 1,749 classified as ARGs and 6,838 as VFGs. The dominant ARGs were associated with antibiotic target alteration and efflux pump mechanisms, while the VFGs were related to adherence and immune modulation functions. While associated within microbial genomes, these ARGs and VFGs were mobile genetic elements like viruses and insertion sequences, distinct from ecosystems with strong human influence. We identified 974 metagenome-assembled genomes (MAGs), with 465 being medium-to-high quality. Of these, 325 (69.9%) contained ARGs, primarily affiliated with Actinomycetota and Pseudomonadota. Additionally, 269 MAGs contained VFGs, with 174 MAGs carrying both ARGs and VFGs, highlighting significant microbial antibiotic resistance and pathogenic potential. Our findings highlight the need for ongoing monitoring of ARGs and VFGs in Antarctica, particularly in light of increasing human activity and climate change.

Metabolic interactions between microbiomes and algal hosts within the phycosphere of marine macroalgae are drawing increasing attention due to their roles in food webs, global nutrient cycles, industries, and their potential as food resources. However, these relations remain poorly understood. In this study, 43 marine macroalgae, including red, brown, and green algae, were collected from the coastal areas of Korea. We identified the bacterial communities within the loosely and tightly attached environments (LAEs and TAEs, respectively) of the phycosphere, along with those in the surrounding seawater, using 16S rRNA gene sequencing. β-Diversity analysis revealed significant differences between the bacterial communities among the three, with minimal variation related to sampling location or algal color. Indicator value analysis identified Pseudoalteromonas (in the LAE and TAE), Psychromonas (in the LAE), Marinomonas (in the LAE), and Litorimonas (in the TAE) as the dominant taxa in the phycosphere, in contrast to seawater. Network analysis suggested positive correlations among taxa within the same environments and negative correlations between those in the LAE and TAE, highlighting their distinct ecological conditions. Analysis using the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States and Kyoto Encyclopedia of Genes and Genomes pathways revealed functional variations between the phycosphere- and seawater-residing microbes. The microbial taxa–function relationships were assessed through Spearman’s rank-order correlation. Additionally, bacterial species belonging to the core taxa were isolated and their genomes sequenced. Their metabolic traits were analyzed via bioinformatics, recognizing key metabolic features essential for symbiotic interactions with algal hosts and survival within the phycosphere. The findings of this study advance our understanding of the marine algal phycosphere microbiome by detailing the metabolic characteristics of potential keystone species.

Understanding how corals adapt to changes in seawater carbonate chemistry is crucial for developing effective coral conservation strategies. Research to date has mostly focused on short-term experiments, overlooking long-term evolutionary effects. Here, we investigated the link between short-term stress responses and long-term genetic adaptations in the coral species Porites pukoensis through experiments under varying CO₂ and alkalinity conditions. Our results showed that alkalinity enrichment significantly increased coral calcification rates by 35%-45% compared to high CO₂ treatment, highlighting the potential of alkalinity enrichment to mitigate acidification impacts. Corals modulated relative expression levels of basic and acidic proteins in response to changes in seawater carbonate chemistry in the stress experiments. Genomic data revealed that this mechanism has been evolutionarily fixed in various organisms adapting to seawater carbonate chemistry. Additionally, both experimental and genomic results showed that extracellular matrix proteins, like collagen with von Willebrand factor type A domain, were modified in response to distinct carbonate environments. Molecular dynamics simulations and in-vitro experiments demonstrated that the structural stability of these proteins contributes to coral resilience under acidified conditions. This study established an integrated framework combining stress experiments, multi-omics analyses, molecular simulations, and in-vitro validation to identify key proteins involved in coral adaptation to acidification.