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Marine bacteria cooperate to degrade lipids in sinking particulate organic matter.

Copper (Cu) redox state has been an important issue in biology and toxicology research, but many research gaps remain to be explored due to the limitations in the detecting techniques. Herein, the regulation of Cu homeostasis, including absorption, translocation, utilization, storage, and elimination behavior is discussed. Cuproptosis, a newly identified type of cell death caused by excessive Cu accumulation, which results in the aggregation of DLAT protein or the loss of Fe-S cluster and finally proteotoxic stress, is reviewed. Several longstanding mysteries of diseases such as Wilson disease and toxic effects, may be attributed to cuproptosis. Furthermore, we review the advanced detection methods and application of Cu(I) and Cu(II), especially the in-situ imaging techniques such as XANES, and chemosensors. Most of the existing studies using these detection techniques focus on the bioaccumulation and toxicity of Cu(I) and Cu(II) in cells and aquatic organisms. Finally, it will be important to identify the roles of Cu(I) and Cu(II) in the growth, development, and diseases of organisms, as well as the relationship between bioaccumulation and toxicity of Cu(I) and Cu(II) in cellular and aquatic toxicology., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The biological pump supplies carbon to the oceans' interior, driving long-term carbon sequestration and providing energy for deep-sea ecosystems 1,2 . Its efficiency is set by transformations of newly formed particles in the euphotic zone, followed by vertical flux attenuation via mesopelagic processes 3 . Depth attenuation of the particulate organic carbon (POC) flux is modulated by multiple processes involving zooplankton and/or microbes 4,5 . Nevertheless, it continues to be mainly parameterized using an empirically derived relationship, the 'Martin curve' 6 . The derived power-law exponent is the standard metric used to compare flux attenuation patterns across oceanic provinces 7,8 . Here we present in situ experimental findings from C-RESPIRE 9 , a dual particle interceptor and incubator deployed at multiple mesopelagic depths, measuring microbially mediated POC flux attenuation. We find that across six contrasting oceanic regimes, representing a 30-fold range in POC flux, degradation by particle-attached microbes comprised 7-29 per cent of flux attenuation, implying a more influential role for zooplankton in flux attenuation. Microbial remineralization, normalized to POC flux, ranged by 20-fold across sites and depths, with the lowest rates at high POC fluxes. Vertical trends, of up to threefold changes, were linked to strong temperature gradients at low-latitude sites. In contrast, temperature played a lesser role at mid- and high-latitude sites, where vertical trends may be set jointly by particle biochemistry, fragmentation and microbial ecophysiology. This deconstruction of the Martin curve reveals the underpinning mechanisms that drive microbially mediated POC flux attenuation across oceanic provinces., (© 2024. The Author(s).)

Dechloranes, including dechlorane 602 (Dec 602), dechlorane 603 (Dec 603), dechlorane 604 (Dec 604), dechlorane plus (DP, including syn- and anti-DP) and mirex, were determined in marine food web from Dalian Bay, Northeast China to investigate their occurrence andtrophic transfer. In all organisms, the detection rates were Dec 602 (99%) > mirex (95%) > Dec 603 (92%) > anti-DP (91%) > syn-DP (82%) > Dec 604 (9.6%). The concentrations were 0.92-16 ng/g lipid weight (lw) for mirex, 0.53-2.3 ng/g lw for syn-DP, 1.1-4.5 ng/g lw for anti-DP, 0.19-5.0 ng/g lw for Dec 602, 0.26-1.9 ng/g lw for Dec 603 and 0.020-0.33 ng/g lw for Dec 604. Significant positive relationships (p < 0.0001) were observed between lipid normalized concentrations and trophic levels for mirex (R 2  = 0.80) and Dec602 (R 2  = 0.82) in food webs, with the calculated TMFs values of 3.09 and 3.39, respectively, indicating the trophic magnification potential of these compounds. For syn-DP, anti-DP, Dec 603 and Dec 604, the similar significant relationships were not found, suggesting that these chemicals do not trophic magnification nor trophic dilution in the food web. With low log K OW values for mirex (7.01) and Dec 602 (8.05), these two compounds have the highest magnifications potentials, while the magnification potential of Dec 603, Dec 604 and DP dramatically decreased because of their extremely big log K OW values (higher than 10). The observed fractional abundance of anti-DP (f anti ) ranged of 0.58-0.69, closing to the one in Chinese industrial products, indicating DP isomers had not undergone significant differences of physicochemical or biological process in the studied food web., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Marine microorganisms offer a promising avenue for the eco-friendly synthesis of nanoparticles due to their unique biochemical capabilities and adaptability to various environments. This study focuses on exploring the potential of a marine bacterial species, Stenotrophomonas rhizophila BGNAK1, for the synthesis of biocompatible copper nanoparticles and their application for hindering biofilms formed by monomicrobial species. The study begins with the isolation of the novel marine S. rhizophila species from marine soil samples collected from the West coast region of Kerala, India. The isolated strain is identified through 16S rRNA gene sequencing and confirmed to be S. rhizophila species. Biosynthesis of copper nanoparticles using S. rhizophila results in the formation of nanoparticles with size of range 10-50 nm. The nanoparticles exhibit a face-centered cubic crystal structure of copper, as confirmed by X-Ray Diffraction analysis. Furthermore, the synthesized nanoparticles display significant antimicrobial activity against various pathogenic bacteria and yeast. The highest inhibitory activity was against Staphylococcus aureus with a zone of 27 ± 1.00 mm and the least activity was against Pseudomonas aeruginosa with a zone of 22 ± 0.50 mm. The zone of inhibition against Candida albicans was 16 ± 0.60 mm. The antibiofilm activity against biofilm-forming clinical pathogens was evidenced by the antibiofilm assay and SEM images. Additionally, the copper nanoparticles exhibit antioxidant activity, as evidenced by their scavenging ability against DPPH, hydroxyl, nitric oxide, and superoxide radicals, as well as their reducing power in the FRAP assay. The study highlights the potential of the marine bacterium S. rhizophila BGNAK1 for the eco-friendly biosynthesis of copper nanoparticles with diverse applications. Synthesized nanoparticles exhibit promising antibiofilm, antimicrobial, and antioxidant properties, suggesting their potential utility in various fields such as medicine, wastewater treatment, and environmental remediation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

As the substitutes of polybrominated diphenyl ethers, organophosphate esters (OPEs) with high concentrations have accumulated in the estuaries, bays, and harbors. However, limited information is available about the OPEs in the estuary organism categories, especially under the multiple industrial pressure. This study investigated the occurrence, bioaccumulation and human consumption implication in wild marine organisms from the Yellow River Estuary, where located many petroleum and chemical manufacturing industries. This study found that concentrations of Σ 13 OPEs ranged from 547 ng/L to 1164 ng/L in seawater (median: 802 ng/L), from 384 to 1366 ng/g dw in the sediment (median: 601 ng/g dw), and from 419 to 959 ng/g dw (median: 560 ng/g dw) in the marine organisms. The congener compositions in the organisms were dominated by alkyl-OPEs (80.7 %), followed by halogenated-OPEs (18.8 %) and aryl-OPEs (0.5 %). Based on the principal component analysis, petrochemical pollution, and industrial wastewater discharge were distinguished as the main plausible sources of OPEs to the YRE ecosystem. Most OPEs had potential or strong bioaccumulation capacity on the organisms, with a positive correlation between log BAF (Bioaccumulation Factor) and log Kow of OPEs. The highest estimated daily intake value of OPEs was tri-n-propyl phosphate, exceeding 300 ng/kg·bw/day via consuming fish. The highest hazard quotients from OPEs ranged from 0.001 to 0.1, indicating a low risk to human health by consuming marine organisms in the YRE. As the consumption of OPEs increases year by year, the risks of OPEs still cannot be ignored., Competing Interests: Declaration of competing interest All authors of this article declare that they have no conflict of interest regarding the publication of this study., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Hydrophobins (HFBs) and cerato-platanins (CPs) are surface-active extracellular proteins produced by filamentous fungi. This study identified two HFB genes (pshyd1 and pshyd2) and one CP gene (pscp) in the marine fungus Paradendryphiella salina. The proteins PsCP, PsHYD2, and PsHYD1 had molecular weights of 12.70, 6.62, and 5.98 kDa, respectively, with isoelectric points below 7. PsHYD1 and PsHYD2 showed hydrophobicity (GRAVY score 0.462), while PsCP was hydrophilic (GRAVY score - 0.202). Stability indices indicated in-solution stability. Mass spectrometry identified 2,922 proteins, including CP but not HFB proteins. qPCR revealed differential gene expression influenced by developmental stage and substrate, with pshyd1 consistently expressed. These findings suggest P. salina's adaptation to marine ecosystems with fewer hydrophobin genes than other fungi but capable of producing surface-active proteins from seaweed carbohydrates. These proteins have potential applications in medical biocoatings, food industry foam stabilizers, and environmental bioremediation., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Industrial and urban activities are major contributors to metal contamination in coastal systems, often impacting the physiology, distribution and diversity of marine invertebrates. This study assessed metal contaminations in sediments, seawater, algae and invertebrates across four armoured systems (harbours) and two natural sites along the south coast of South Africa. Bioaccumulation factors such as Biosediment (BSAF), Biowater (BWAF), Bioaccumulation (BAF) and bioremediation of metals by invertebrate bioindicators were also determined. Spatial variation in metal concentrations were observed, however, bioaccumulation of metals was site and species-specific. Invertebrates bioaccumulated higher metal concentrations in armoured than natural sites, with filter feeders exhibiting higher concentrations than grazers. Among filter feeders, Octomeris angulosa and Crassostrea gigas bioaccumulated elevated aluminium (Al), arsenic (As), chromium (Cr), zinc (Zn) and copper (Cu), while, Perna perna accumulated elevated nickel (Ni), cadmium (Cd) and lead (Pb). Among grazers, Siphonaria serrata and Scutellastra longicosta bioaccumulated elevated Al, Cr, Cd, cobalt (Co), Cu, Ni and Zn. Bioaccumulation factors indicated that (As, Ni, Zn) were bioaccumulated by algae, and invertebrates from sediment (BSAF>1) and from seawater (BWAF>1). Additionally, invertebrates bioaccumulated metals from their prey item, algae as indicated by (BAF>1). Arsenic Cd and Pb in invertebrates were above the maximum limit set for human consumption by various regulatory bodies. Our findings underscore the significant role of coastal invertebrates in bioaccumulating and bioremediating metals, suggesting a natural mechanism for water quality enhancement, especially in urbanised coastal areas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The physiology and ecology of particle-associated marine bacteria are of growing interest, but our knowledge of their aggregation behavior and mechanisms controlling their association with particles remains limited. We have found that a particle-associated isolate, Alteromonas sp. ALT199 strain 4B03, and the related type-strain A. macleodii 27126 both form large (>500 μm) aggregates while growing in rich medium. A non-clumping variant (NCV) of 4B03 spontaneously arose in the lab, and whole-genome sequencing revealed a partial deletion in the gene encoding UDP-glucose-4-epimerase ( galEΔ 308-324). In 27126, a knock-out of galE ( ΔgalE ::km r ) resulted in a loss of aggregation, mimicking the NCV. Microscopic analysis shows that both 4B03 and 27126 rapidly form large aggregates, whereas their respective galE mutants remain primarily as single planktonic cells or clusters of a few cells. Strains 4B03 and 27126 also form aggregates with chitin particles, but their galE mutants do not. Alcian Blue staining shows that 4B03 and 27126 produce large transparent exopolymer particles (TEP), but their galE mutants are deficient in this regard. This study demonstrates the capabilities of cell-cell aggregation, aggregation of chitin particles, and production of TEP in strains of Alteromonas , a widespread particle-associated genus of heterotrophic marine bacteria. A genetic requirement for galE is evident for each of the above capabilities, expanding the known breadth of requirement for this gene in biofilm-related processes., Importance: Heterotrophic marine bacteria have a central role in the global carbon cycle. Well-known for releasing CO2 by decomposition and respiration, they may also contribute to particulate organic matter (POM) aggregation, which can promote CO2 sequestration via the formation of marine snow. We find that two members of the prevalent particle-associated genus Alteromonas can form aggregates comprising cells alone or cells and chitin particles, indicating their ability to drive POM aggregation. In line with their multivalent aggregation capability, both strains produce TEP, an excreted polysaccharide central to POM aggregation in the ocean. We demonstrate a genetic requirement for galE in aggregation and large TEP formation, building our mechanistic understanding of these aggregative capabilities. These findings point toward a role for heterotrophic bacteria in POM aggregation in the ocean and support broader efforts to understand bacterial controls on the global carbon cycle based on microbial activities, community structure, and meta-omic profiling., Competing Interests: The authors declare no conflict of interest.

Amylin is part of the endocrine pancreatic system that contributes to glycemic control, regulating blood glucose levels. However, human amylin has a high tendency to aggregate, forming isolated amylin deposits that are observed in patients with type 2 diabetes mellitus. In search of new inhibitors of amylin aggregation, we undertook the chemical analyses of five marine macroorganisms encountered in high populations in the Red Sea and selected a panel of 10 metabolites belonging to different chemical classes to evaluate their ability to inhibit the formation of amyloid deposits in the human amylin peptide. The thioflavin T assay was used to examine the kinetics of amyloid aggregation, and atomic force microscopy was employed to conduct a thorough morphological examination of the formed fibrils. The potential ability of these compounds to interact with the backbone of peptides and compete with β-sheet formation was analyzed by quantum calculations, and the interactions with the amylin peptide were computationally examined using molecular docking. Despite their structural similarity, it could be observed that the hydrophobic and hydrogen bond interactions of pyrrolidinones 9 and 10 with the protein sheets result in one case in a stable aggregation, while in the other, they cause distortion from aggregation.

The role of the gut microbiota in host physiology has been previously elucidated for some marine organisms, but little information is available on their metabolic activity involved in transformation of environmental pollutants. This study assessed the metabolic profiles of the gut microbial cultures from grouper (Epinephelus coioides), green mussel (Perna viridis) and giant tiger prawn (Penaeus monodon) and investigated their transformation mechanisms to typical plastic additives. Community-level physiological profiling analysis confirmed the utilization profiles of the microbial cultures including carbon sources of carbohydrates, amines, carboxylic acids, phenolic compounds, polymers and amino acids, and the plastic additives of organophosphate flame retardants, tetrabromobisphenol A derivates and bisphenols. Using in vitro incubation, triphenyl phosphate (TPHP) was found to be rapidly metabolized into diphenyl phosphate by the gut microbiota as a representative ester-containing plastic additive, whereas the transformation of BPA (a representative phenol) was relatively slower. Interestingly, all three kinds of microbial cultures efficiently transformed the hepatic metabolite of BPA (BPA-G) back to BPA, thereby increasing its bioavailability in the body. The specific enzyme analysis confirmed the ability of the gut microbiota to perform the metabolic reactions. The results of 16S rRNA sequencing and network analysis revealed that the genera Escherichia-Shigella, Citrobacter, and Anaerospora were functional microbes, and their collaboration with fermentative microbes played pivotal roles in the transformation of the plastic additives. The structure-specific transformations by the gut microbiota and their distinct bioavailability deserve more attention in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Marine microorganisms are increasingly recognized as primary producers of marine secondary metabolites, drawing growing research interest. Many of these organisms are unculturable, posing challenges for study. Metagenomic techniques enable research on these unculturable microorganisms, identifying various biosynthetic gene clusters (BGCs) related to marine microbial secondary metabolites, thereby unveiling their secrets. This review comprehensively analyses metagenomic methods used in discovering marine microbial secondary metabolites, highlighting tools commonly employed in BGC identification, and discussing the potential and challenges in this field. It emphasizes the key role of metagenomics in unveiling secondary metabolites, particularly in marine sponges and tunicates. The review also explores current limitations in studying these metabolites through metagenomics, noting how long-read sequencing technologies and the evolution of computational biology tools offer more possibilities for BGC discovery. Furthermore, the development of synthetic biology allows experimental validation of computationally identified BGCs, showcasing the vast potential of metagenomics in mining marine microbial secondary metabolites., (© 2024 The Author(s). Microbial Biotechnology published by John Wiley & Sons Ltd.)

Low-latitude (LL) oceans account for up to half of global net primary production and export 1-5 . It has been argued that the Southern Ocean dominates LL primary production and export 6 , with implications for the response of global primary production and export to climate change 7 . Here we applied observational analyses and sensitivity studies to an individual model to show, instead, that 72% of LL primary production and 55% of export is controlled by local mesopelagic macronutrient cycling. A total of 34% of the LL export is sustained by preformed macronutrients supplied from the Southern Ocean via a deeper overturning cell, with a shallow preformed northward supply, crossing 30° S through subpolar and thermocline water masses, sustaining only 7% of the LL export. Analyses of five Coupled Model Intercomparison Project Phase 6 (CMIP6) models, run under both high-emissions low-mitigation (shared socioeconomic pathway (SSP5-8.5)) and low-emissions high-mitigation (SSP1-2.6) climate scenarios for 1850-2300, revealed significant across-model disparities in their projections of not only the amplitude, but also the sign, of LL primary production. Under the stronger SSP5-8.5 forcing, with more substantial upper-ocean warming, the CMIP6 models that account for temperature-dependent remineralization promoted enhanced LL mesopelagic nutrient retention under warming, with this providing a first-order contribution to stabilizing or increasing, rather than decreasing, LL production under high emissions and low mitigation. This underscores the importance of a mechanistic understanding of mesopelagic remineralization and its sensitivity to ocean warming for predicting future ecosystem changes., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Microplastics pose a threat to marine environments through their physical presence and as vectors of chemical pollutants. However, the impact of microplastics on the accumulation and human health risk of chemical pollutants in marine organisms remains largely unknown. In this study, we investigated the microplastics and polycyclic aromatic hydrocarbons (PAHs) pollution in marine organisms from Sanggou Bay and analyzed their correlations. Results showed that microplastic and PAHs concentration ranged from 1.23 ± 0.23 to 5.77 ± 1.10 items/g, from 6.98 ± 0.45 to 15.07 ± 1.25 μg/kg, respectively. The microplastic abundance, particularly of fibers, transparent and color plastic debris, correlates strongly with PAH contents, indicating that microplastics increase the bioaccumulation of PAHs and microplastics with these characteristics have a significant vector effect on PAHs. Although consuming seafood from Sanggou Bay induce no carcinogenic risk from PAHs, the presence of microplastics in organisms can significantly increases incremental lifetime cancer risk of PAHs. Thus, microplastics can serve as transport vectors for PAHs with implications for the potential health risks to human through consumption. This study provides new insight into the risks of microplastics in marine environments., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Declaration of Competing Interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Halogenated flame retardants (HFRs) have attracted global attention owing to their adverse effects on ecosystems and humans. The Shandong Peninsula is the largest manufacturing base for HFRs in East Asia, yet its impacts on marine ecosystems are unclear. Seventeen HFRs were analyzed in organisms captured from the Xiaoqing River estuary, Bohai Sea (BS), Yellow Sea and Northern East China Sea to investigate the distribution and bioaccumulation of HFRs on a broad scale. The results showed a downward trend in ΣHFR concentrations from the estuary (37.7 ng/g lw on average) to Laizhou Bay (192 ng/g lw) and to coastal seas (3.13 ng/g lw). The concentrations of ΣHFRs were significantly higher in demersal fish (0.71-198 ng/g lw) and benthic invertebrates (0.81-3340 ng/g lw) than in pelagic fish (0.30-27.6 ng/g lw), reflecting a habitat dependence. The concentrations of higher-brominated homologs were greater in benthic invertebrates, whereas a greater level of lower-brominated PBDE congeners was observed in fish, suggesting different profiles between species. Furthermore, the analogue composition of HFRs in fish was similar to that in the dissolved phase of seawater, whereas the HFR pattern in benthic invertebrates was consistent with the profile in sediment. The concentrations of HFRs in organisms vary widely depending on emissions from anthropogenic activities, whereas bioaccumulation patterns are strongly influenced by species and habitat., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Chemosynthesis is a metabolic process that transfers carbon to the biosphere using reduced compounds. It is well recognised that chemosynthesis occurs in much of the ocean, but it is often thought to be a negligible process compared to photosynthesis. Here we propose that chemosynthesis is the underlying process governing primary production in much of the ocean and suggest that it extends to a much wider range of compounds, microorganisms, and ecosystems than previously thought. In turn, this process has had a central role in controlling marine biogeochemistry, ecology, and carbon budgets across the vast realms of the ocean, from the dawn of life to contemporary times., Competing Interests: Declaration of interests There are no interests to declare., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Aquatic plants are a crucial component of the aquatic ecosystem in the Tibetan Plateau region. Researching the adaptability of plateau aquatic plants in photosynthesis to the plateau environment can enhance understanding of the operational mechanisms of plateau ecosystems, thereby providing a scientific basis for the protection and management of plateau aquatic ecosystems. This study presents an investigation of photosynthetic inorganic carbon utilization strategies and photosynthetic efficiency of 17 aquatic plants under natural growing conditions in Niyang River basin on the Tibetan Plateau. In pH-drift experiments, 10 of 17 species were able to utilize HCO 3 - , and environmental factors like water pH were shown to have a significant effect on the ability of the tested species to utilize HCO 3 - . Titratable acidity in the leaves of Stuckenia filiformis, Zannichellia palustris, Batrachium bungei, and Myriophyllum spicatum showed significant diurnal fluctuations at certain sampling sites, indicating the presence of CAM. In B. bungei, water pH positively correlated with CAM activity, while CO 2 concentration negatively correlated with CAM activity. The chlorophyll fluorescence analysis revealed that aquatic plants inhabiting the Tibetan Plateau exhibited photosynthetic adaptations. In conclusion, the aquatic plants on the Tibetan Plateau employ diverse strategies for utilizing inorganic carbon during photosynthesis, exhibiting their flexible adaptability to the native high-altitude habitats of the Tibetan Plateau., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Marine organisms' lipid metabolism contributes to marine ecosystems by producing a variety of lipid molecules. Historically, research focused on the lipid metabolism of the organisms themselves. Recent microbiome studies, however, have revealed that gut microbial communities influence the amount and type of lipids absorbed by organisms, thereby altering the organism's lipid metabolism. This has highlighted the growing importance of research on gut microbiota. This review highlights mechanisms by which gut microbiota facilitate lipid digestion and diversify the lipid pool in aquatic animals through the accelerated degradation of exogenous lipids and the transformation of lipid molecules. We also assess how environmental factors and pollutants, along with the innovative use of probiotics, interact with the gut microbiome to influence lipid metabolism within the host. We aim to elucidate the complex interactions between lipid metabolism and gut microbiota in aquatic animals by synthesizing current research and identifying knowledge gaps, providing a foundation for future explorations., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study examined the sediment metal fractions and availability to infer bioaccumulation in marine harbor benthic organisms. Total metals were analyzed using atomic absorption spectrometry and inductively coupled plasma-optical emission spectrometry for chemical fractions and organisms. The results showed similar metal concentrations and distribution driven by rivers and harbor pollution. We found significant differences in metal accumulation in marine benthic groups, highest in scavenger species. Their metal concentrations in decreasing order were 1.97-4568, 0.10-1260, 1.64-159, and 0.105-112 μg g -1 dw for hermit crabs, forams, bivalves, and polychaetes. Moreover, certain organisms, such as tusk shells, sea pens, bivalves, forams, and isopods, may exhibit selective metal accumulation. Biota-sediment accumulation factors (>1) were highest for essential metals like Cu, Zn, and Mn, while toxic metals like As, Cr, Co, and Ni increased. This concurrent assessment provides more comprehensive data for metal bioaccumulation in marine benthic ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Pyruvate (Pyr) is the end product of the glycolysis pathway. Pyr is also renewable and is further metabolized to produce formate, which is the precursor of H 2 , via pyruvate formate lyase (PFL) under anaerobic conditions. The formate is excluded and re-imported via the formate channel and is then converted to H 2 via the formate hydrogenlyase (FHL) complex. In H 2 producing marine vibrios, such as Vibrio tritonius and Vibrio porteresiae in the Porteresiae clade of the family Vibrionaceae, apparent but inefficient H 2 production from Pyr has been observed. To elucidate the molecular mechanism of why this inefficient H 2 production is observed in Pry-metabolized marine vibrio cells and how glycolysis affects those H 2 productions of marine vibrios, the "Core Transcriptome" approach to find common gene expressions of those two major H 2 producing Vibrio species in Pyr metabolism was first applied. In the Pyr-metabolized vibrio cells, genes for the "Phosphoenolpyruvate (PEP)-Pyruvate-Oxalate (PPO)" node, due to energy saving, and PhoB-, RhaR-, and DeoR-regulons were regulated. Interestingly, a gene responsible for oxalate/formate family antiporter was up-regulated in Pyr-metabolized cells compared to those of Glc-metabolized cells, which provides new insights into the uses of alternative formate exclusion mechanics due to energy deficiencies in Pyr-metabolized marine vibrios cells. We further discuss the contribution of the Embden-Meyerhof-Parnas (EMP) pathway to efficient H 2 production in marine vibrios., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: A growing number of studies have demonstrated that the polar regions have the potential to be a significant repository of microbial resources and a potential source of active ingredients. Genome mining strategy plays a key role in the discovery of bioactive secondary metabolites (SMs) from microorganisms. This work highlighted deciphering the biosynthetic potential of an Arctic marine-derived strain Aspergillus sydowii MNP-2 by a combination of whole genome analysis and antiSMASH as well as feature-based molecular networking (MN) in the Global Natural Products Social Molecular Networking (GNPS)., Results: In this study, a high-quality whole genome sequence of an Arctic marine strain MNP-2, with a size of 34.9 Mb was successfully obtained. Its total number of genes predicted by BRAKER software was 13,218, and that of non-coding RNAs (rRNA, sRNA, snRNA, and tRNA) predicted by using INFERNAL software was 204. AntiSMASH results indicated that strain MNP-2 harbors 56 biosynthetic gene clusters (BGCs), including 18 NRPS/NRPS-like gene clusters, 10 PKS/PKS-like gene clusters, 8 terpene synthse gene clusters, 5 indole synthase gene clusters, 10 hybrid gene clusters, and 5 fungal-RiPP gene clusters. Metabolic analyses of strain MNP-2 grown on various media using GNPS networking revealed its great potential for the biosynthesis of bioactive SMs containing a variety of heterocyclic and bridge-ring structures. For example, compound G-8 exhibited a potent anti-HIV effect with an IC 50 value of 7.2 nM and an EC 50 value of 0.9 nM. Compound G-6 had excellent in vitro cytotoxicities against the K562, MCF-7, Hela, DU145, U1975, SGC-7901, A549, MOLT-4, and HL60 cell lines, with IC 50 values ranging from 0.10 to 3.3 µM, and showed significant anti-viral (H1N1 and H3N2) activities with IC 50 values of 15.9 and 30.0 µM, respectively., Conclusions: These findings definitely improve our knowledge about the molecular biology of genus A. sydowii and would effectively unveil the biosynthetic potential of strain MNP-2 using genomics and metabolomics techniques., (© 2024. The Author(s).)

Wastewater containing tetrabromobisphenol A (TBBPA), a commonly used flame retardant found in wastewater, can present significant toxic effects on biota, yet its impact on tropical freshwater environments is not well understood. This study explores the effectiveness of two independent anaerobic treatment systems, the acidogenic reactor (AR) and the methanogenic reactor (MR), for the ecotoxicity reduction of TBBPA-rich wastewater in four tropical freshwater species. Despite presenting good physicochemical performance and reduced toxicity of the influent for most species, AR and MR treatments remain acute and chronic toxicity. Overall, MR exhibited greater efficacy in reducing influent toxicity compared with AR. TBBPA bioaccumulation was observed in Chironomus sancticaroli after short-term exposure to 100% MR effluent. Multigenerational exposures highlighted changes in the wing length of C. sancticaroli, showing decreases after influent and AR exposures and increases after MR exposures. These findings underscore the need for ecotoxicological tools in studies of new treatment technologies, combining the removal of emerging contaminants with safeguarding aquatic biota. PRACTITIONER POINTS: Acidogenic and methanogenic reactors reduced the acute and chronic toxicity of wastewater containing tetrabromobisphenol A. Both treatments still exhibit toxicity, inducing short- and long-term toxic effects on four native tropical species. The aquatic species Pristina longiseta was most sensitive to effluents from acidogenic and methanogenic reactors. TBBPA concentrations recovered from Chironomus sancticaroli bioaccumulation analysis ranged from 1.07 to 1.35 μg g -1 . Evaluating new treatment technologies with multiple species bioassays is essential for a comprehensive effluent toxicity assessment and ensuring aquatic safety., (© 2024 Water Environment Federation.)

Nitrosopumilus maritimus is an ammonia-oxidizing archaeon that is crucial to the global nitrogen cycle 1,2 . A critical step for nitrogen oxidation is the entrapment of ammonium ions from a dilute marine environment at the cell surface and their subsequent channelling to the cell membrane of N. maritimus. Here we elucidate the structure of the molecular machinery responsible for this process, comprising the surface layer (S-layer), using electron cryotomography and subtomogram averaging from cells. We supplemented our in situ structure of the ammonium-binding S-layer array with a single-particle electron cryomicroscopy structure, revealing detailed features of this immunoglobulin-rich and glycan-decorated S-layer. Biochemical analyses showed strong ammonium binding by the cell surface, which was lost after S-layer disassembly. Sensitive bioinformatic analyses identified similar S-layers in many ammonia-oxidizing archaea, with conserved sequence and structural characteristics. Moreover, molecular simulations and structure determination of ammonium-enriched specimens enabled us to examine the cation-binding properties of the S-layer, revealing how it concentrates ammonium ions on its cell-facing side, effectively acting as a multichannel sieve on the cell membrane. This in situ structural study illuminates the biogeochemically essential process of ammonium binding and channelling, common to many marine microorganisms that are fundamental to the nitrogen cycle., (© 2024. The Author(s).)

Due to the anthropogenic increase of atmospheric CO 2 emissions, humanity is facing the negative effects of rapid global climate change. Both active emission reduction and carbon dioxide removal (CDR) technologies are needed to meet the Paris Agreement and limit global warming to 1.5 °C by 2050. One promising CDR approach is coastal enhanced weathering (CEW), which involves the placement of sand composed of (ultra)mafic minerals like olivine in coastal zones. Although the large-scale placement of olivine sand could beneficially impact the planet through the consumption of atmospheric CO 2 and reduction in ocean acidification, it may also have physical and geochemical impacts on benthic communities. The dissolution of olivine can release dissolved constituents such as trace metals that may affect marine organisms. Here we tested acute and chronic responses of marine invertebrates to olivine sand exposure, as well as examined metal accumulation in invertebrate tissue resulting from olivine dissolution. Two different ecotoxicological experiments were performed on a range of benthic marine invertebrates (amphipod, polychaete, bivalve). The first experiment included acute and chronic survival and growth tests (10 and 20 days, respectively) of olivine exposure while the second had longer (28 day) exposures to measure chronic survival and bioaccumulation of trace metals (e.g. Ni, Cr, Co) released during olivine sand dissolution. Across all fauna we observed no negative effects on acute survival or chronic growth resulting solely from olivine exposure. However, over 28 days of exposure, the bent-nosed clam Macoma nasuta experienced reduced burrowing and accumulated 4.2 ± 0.7 μg g ww -1 of Ni while the polychaete Alitta virens accumulated 3.5 ± 0.9 μg g ww -1 of Ni. No significant accumulation of any other metals was observed. Future work should include longer-term laboratory studies as well as CEW field studies to validate these findings under real-world scenarios., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Emilia Jankowska, Francesc Montserrat, Stephen J. Romaniello, Nathan G. Walworth, Grace M. Andrews reports financial support was provided by Cisco Foundation Global Impact Grant. Emilia Jankowska, Francesc Montserrat, Stephen J. Romaniello, Nathan G. Walworth, Grace M. Andrews reports financial support was provided by Grantham Foundation for the Protection of the Environment. Emilia Jankowska, Francesc Montserrat, Stephen J. Romaniello, Nathan G. Walworth, Grace M. Andrews reports financial support was provided by Treadright Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Marine heterotrophic prokaryotes primarily take up ambient substrates using transporters. The patterns of transporters targeting particular substrates shape the ecological role of heterotrophic prokaryotes in marine organic matter cycles. Here, we report a size-fractionated pattern in the expression of prokaryotic transporters throughout the oceanic water column due to taxonomic variations, revealed by a multi-"omics" approach targeting ATP-binding cassette (ABC) transporters and TonB-dependent transporters (TBDTs). Substrate specificity analyses showed that marine SAR11, Rhodobacterales, and Oceanospirillales use ABC transporters to take up organic nitrogenous compounds in the free-living fraction, while Alteromonadales, Bacteroidetes, and Sphingomonadales use TBDTs for carbon-rich organic matter and metal chelates on particles. The expression of transporter proteins also supports distinct lifestyles of deep-sea prokaryotes. Our results suggest that transporter divergency in organic matter assimilation reflects a pronounced niche separation in the prokaryote-mediated organic matter cycles.

Background: Lovastatin has widespread applications thanks to its multiple pharmacological effects. Fermentation by filamentous fungi represents the major way of lovastatin production. However, the current lovastatin productivity by fungal fermentation is limited and needs to be improved., Results: In this study, the lovastatin-producing strains of Aspergillus terreus from marine environment were screened, and their lovastatin productions were further improved by genetic engineering. Five strains of A. terreus were isolated from various marine environments. Their secondary metabolites were profiled by metabolomics analysis using Ultra Performance Liquid Chromatography-Mass spectrometry (UPLC-MS) with Global Natural Products Social Molecular Networking (GNPS), revealing that the production of secondary metabolites was variable among different strains. Remarkably, the strain of A. terreus MJ106 could principally biosynthesize the target drug lovastatin, which was confirmed by High Performance Liquid Chromatography (HPLC) and gene expression analysis. By one-factor experiment, lactose was found to be the best carbon source for A. terreus MJ106 to produce lovastatin. To improve the lovastatin titer in A. terreus MJ106, genetic engineering was applied to this strain. Firstly, a series of strong promoters was identified by transcriptomic and green fluorescent protein reporter analysis. Then, three selected strong promoters were used to overexpress the transcription factor gene lovE encoding the major transactivator for lov gene cluster expression. The results revealed that compared to A. terreus MJ106, all lovE over-expression mutants exhibited significantly more production of lovastatin and higher gene expression. One of them, LovE-b19, showed the highest lovastatin productivity at a titer of 1512 mg/L, which represents the highest production level reported in A. terreus., Conclusion: Our data suggested that combination of strain screen and genetic engineering represents a powerful tool for improving the productivity of fungal secondary metabolites, which could be adopted for large-scale production of lovastatin in marine-derived A. terreus., (© 2024. The Author(s).)

Recently, aquatic microcosms have attracted considerable attention because they can be used to simulate natural aquatic ecosystems. First, to evaluate the development of trends, hotspots, and national cooperation networks in the field, bibliometric analysis was performed based on 1841 articles on aquatic microcosm (1962-2022). The results of the bibliometric analysis can be categorized as follows: (1) Aquatic microcosm research can be summarized in two sections, with the first part focusing on the ecological processes and services of aquatic ecosystems, and the second focusing on the toxicity and degradation of pollutants. (2) The United States (number of publications: 541, proportion: 29.5%) and China (248, 13.5%) are the two most active countries. Second, to determine whether there is a difference between single-species and microcosm tests, that is, to perform different-tier assessments, the recommended aquatic safety thresholds in risk assessment [i.e., the community-level no effect concentration (NOEC community ), hazardous concentrations for 5% of species (HC 5 ) and predicted no effect concentration (PNEC)] were compared based on these tests. There was a significant difference between the NOEC community and HC 5 (P < 0.05). Moreover, regression models predicting microcosm toxicity values were constructed to provide a reference for ecological systemic risk assessments based on aquatic microcosms., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study assessed Rhodotorula paludigena CM33's growth and β-carotene production in a 22-L bioreactor for potential use as an aquatic animal feed supplement. Optimizing the feed medium's micronutrient concentration for high-cell-density fed-batch cultivation using glucose as the carbon source yielded biomass of 89.84 g/L and β-carotene concentration of 251.64 mg/L. Notably, using sucrose as the carbon source in feed medium outperforms glucose feeds, resulting in a β-carotene concentration of 285.00 mg/L with a similar biomass of 87.78 g/L. In the fed-batch fermentation using Sucrose Feed Medium, R. paludigena CM33 exhibited high biomass production rates (Q x ) of 0.91 g/L.h and remarkable β-carotene production rates (Q p ) of 2.97 mg/L.h. In vitro digestibility assays showed that R. paludigena CM33, especially when cultivated using sucrose, enhances protein digestibility affirming its suitability as an aquatic feed supplement. Furthermore, R. paludigena CM33's nutrient-rich profile and probiotic potential make it an attractive option for aquatic nutrition. This research highlights the importance of cost-effective carbon sources in large-scale β-carotene production for aquatic animal nutrition., (© 2024. The Author(s).)

Environmental research plays a crucial role in formulating novel approaches to pollution management and preservation of biodiversity. This study aims to assess the potential harm of pharmaceutical triclosan (TCS) to non-target aquatic organism, the mussel Mytilus galloprovincialis. Furthermore, our study investigates the potential effectiveness of TiO 2 and ZnO nanomaterials (TiO 2 NPs and ZnO NPs) in degrading TCS. To ascertain the morphology, structure, and stability of the nanomaterials, several chemical techniques were employed. To evaluate the impact of TCS, TiO 2 NPs, and ZnO NPs, both physiological (filtration rate (FR) and respiration rate (RR)), antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST)) activities and malondialdehyde (MDA) contents were measured in M. galloprovincialis gills and digestive gland. The mussel's responses varied depending on the contaminant, concentration, and organ, underscoring the significance of compiling these factors in ecotoxicity tests. The main toxic mechanisms of TCS and ZnO NPs at a concentration of 100 μg/L were likely to be a decrease in FR and RR, an increase in oxidative stress, and increased lipid peroxidation. Our findings indicate that a mixture of TCS and NPs has an antagonist effect on the gills and digestive gland. This effect is particularly notable in the case of TCS2 = 100 μg/L combined with TiO 2 NP2 = 100 μg/L, which warrants further investigation to determine the underlying mechanism. Additionally, our results suggest that TiO 2 NPs are more effective than ZnO NPs at degrading TCS, which may have practical implications for pharmaceutical control in marine ecosystems and in water purification plants. In summary, our study provides valuable information on the impact of pharmaceuticals on non-target organisms and sheds light on potential solutions for their removal from aqueous environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The enormous potential attributed to prodigiosin regarding its applicability as a natural pigment and pharmaceutical agent justifies the development of sound bioprocesses for its production. Using a Serratia rubidaea strain isolated from a shallow-water hydrothermal vent, optimization of the growth medium composition was carried out. After medium development, the bacterium temperature, light and oxygen needs were studied, as was growth inhibition by product concentration. The implemented changes led to a 13-fold increase in prodigiosin production in a shake flask, reaching 19.7 mg/L. The conditions allowing the highest bacterial cell growth and prodigiosin production were also tested with another marine strain: S. marcescens isolated from a tide rock pool was able to produce 15.8 mg/L of prodigiosin. The bioprocess with S. rubidaea was scaled up from 0.1 L shake flasks to 2 L bioreactors using the maintenance of the oxygen mass transfer coefficient ( k L a ) as the scale-up criterion. The implemented parameters in the bioreactor led to an 8-fold increase in product per biomass yield and to a final concentration of 293.1 mg/L of prodigiosin in 24 h.

Ocean acidification and deoxygenation co-occur in marine environments, causing deterioration of marine ecosystems. However, effects of compound stresses on marine organisms and their physiological coping mechanisms are largely unknown. Here, we show how high pCO 2 and low dissolved oxygen (DO) cause transcriptomic changes in eggs of a demersal fish (Sillago japonica), which are fully exposed to such stresses in natural environment. Overall gene expression was affected more strongly by low DO than by high pCO 2 . Enrichment analysis detected significant stress responses such as glycolytic processes in response to low DO. Increased expression of a group of glycolytic genes under low DO conditions is presumably because oxygen depletion disables the electron transfer pathway, complementing ATP production in the glycolytic pathway. Contrary to expectations, apparent mitigation of gene expression changes was dominant under combined stress conditions, and may represent an innate fish adaptive trait for severe environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Microplastics play a significant role in interactions between organisms and hydrophobic organic contaminants (HOCs), leading to a joint toxic effect on aquatic organisms. This study extensively investigated the tissue-specific accumulation of polychlorinated biphenyls (PCBs) resulting from different sized microplastics in tilapia (Oreochromis mossambicus) using a passive dosing device. Based on biological feeding behavior considerations, 1 mm and 2 μm polystyrene (PS) microplastics with concentrations of 2 and 5 mg L -1 were investigated. A physiologically based toxicokinetic (PBTK) model was applied to evaluate the exchange kinetics and fluxes among the tissues. Moreover, an in vitro simulation experiment was conducted to theoretically validate the vector effect. The findings demonstrated that the effects caused by HOCs and microplastics on organisms were influenced by multiple factors such as size and surface properties. The mass transfer kinetics of HOCs in specific tissues were closely related to their adsorption capacity and position microplastics could reach. Specifically, although 2 μm microplastics exhibited high adsorption capacity for PCBs, they were only retained in the intestines and did not significantly contribute to the bioaccumulation of PCBs in gills or muscle. While 1 mm microplastics were ingested but just paused in the mouth and subsequently flew through the gills with oral mucus. Their vector effects increased the desorption of microplastic-bound PCB-118 in the gill mucus microcosm, thereby facilitating the mass transfer and accumulation of PCB-118 in gills and muscle. This study sheds new light on how the size-dependent vector generated by microplastics affects the tissue-specific accumulation of HOCs in aquatic organisms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Heavy metal pollution has significant impacts on aquatic fauna and flora. It accumulates in marine organisms, both plants and animals, which are then consumed by humans. This can lead to various health problems, such as organ damage and the development of cancer. Additionally, this pollution causes biological magnification, where the toxicity concentration gradually increases as aquatic organisms continuously accumulate metals. This process results in apoptotic mechanisms, antioxidant defence, and inflammation, which are reflected at the gene expression level. However, there is limited research on specific heavy metals and their effects on fish organs. The concentration of metal contamination and accumulation in different tropical environments is a concern due to their toxicity to living organisms. Therefore, this review focuses on determining the influences of metals on fish and their effects on specific organs, including DNA alterations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The extent to which chemicals bioaccumulate in aquatic and terrestrial organisms represents a fundamental consideration for chemicals management efforts intended to protect public health and the environment from pollution and waste. Many chemicals, including most pharmaceuticals and personal care products (PPCPs), are ionizable across environmentally relevant pH gradients, which can affect their fate in aquatic and terrestrial systems. Existing mathematical models describe the accumulation of neutral organic chemicals and weak acids and bases in both fish and plants. Further model development is hampered, however, by a lack of mechanistic insights for PPCPs that are predominantly or permanently ionized. Targeted experiments across environmentally realistic conditions are needed to address the following questions: (1) What are the partitioning and sorption behaviors of strongly ionizing chemicals among species? (2) How does membrane permeability of ions influence bioaccumulation of PPCPs? (3) To what extent are salts and associated complexes with PPCPs influencing bioaccumulation? (4) How do biotransformation and other elimination processes vary within and among species? (5) Are bioaccumulation modeling efforts currently focused on chemicals and species with key data gaps and risk profiles? Answering these questions promises to address key sources of uncertainty for bioaccumulation modeling of ionizable PPCPs and related contaminants. Environ Toxicol Chem 2024;43:502-512. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

The usage of typical pharmaceuticals and personal care products (PPCPs) such as cardiovascular and lipid-modulating drugs in clinical care accounts for the largest share of pharmaceutical consumption in most countries. Atorvastatin (ATV), one of the most commonly used lipid-lowering drugs, is frequently detected with lower concentrations in aquatic environments owing to its wide application, low removal, and degradation rates. However, the adverse effects of ATV on non-target aquatic organisms, especially the molecular mechanisms behind the toxic effects, still remain unclear. Therefore, this study investigated the potentially toxic effects of ATV exposure (including environmental concentrations) on yellowstripe goby (Mugilogobius chulae) and addressed the multi-dimensional responses. The results showed that ATV caused typical hepatotoxicity to M. chulae. ATV interfered with lipid metabolism by blocking fatty acid β-oxidation and led to the over-consumption of lipids. Thus, the exposed organism was obliged to alter the energy supply patterns and substrates utilization pathways to keep the normal energy supply. In addition, the higher concentration of ATV exposure caused oxidative stress to the organism. Subsequently, M. chulae triggered the autophagy and apoptosis processes with the help of key stress-related transcriptional regulators FOXOs and Sestrins to degrade the damaged organelles and proteins to maintain intracellular homeostasis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Despite the widespread application of strobilurin fungicides (SFs) in agriculture, little is known about their distribution and bioaccumulation in aquatic ecosystems. In this study, the concentrations of 12 SFs and two of their metabolites were determined in abiotic (water and sediment; n = 83) and biotic (plant, algae, zooplankton, and fish; n = 123) samples collected from a subtropical freshwater ecosystem, namely, Dongjiang River wetland, in southern China. Among the 12 SFs measured, azoxystrobin (AZ) was the major fungicide found in surface water (median: 2.20 ng/L) and sediment (0.064 ng/g dry wt.). Azoxystrobin acid (AZ-acid), a metabolite of AZ, was the major analyte in the plant samples and had a median concentration at 0.36 ng/g dry wt. In algae and zooplankton, (Z)-metominostrobin was the predominant fungicide and had median concentrations of 3.52 and 5.55 ng/g dry wt., respectively. In fish muscle, dimoxystrobin (DIMO) was the major SF and had a median concentration of 0.47 ng/g dry wt. The bioconcentration factor (BCF) values of AZ-acid, trifloxystrobin (TFS), and pyraclostrobin (PYR) in algae and zooplankton and AZ-acid, PYR, TFS, TFS-acid, picoxystrobin, and DIMO in fish muscle exceeded 1000 L/kg (algae, zooplankton, and fish concentrations were expressed on a dry weight basis), suggesting that these fungicides can accumulate in biota. A positive association between log BCFs of SFs in fish and logKow of SFs and a negative correlation between log BCFs and the log solubility index were observed. Additionally, the risk quotient (RQ) was calculated to evaluate the potential ecotoxicological risk of SFs to different aquatic organisms (algae, zooplankton, and fish). The PYR and DIMO concentrations at 19 sampling sites had RQ values >0.1, indicating moderate ecotoxicological risks to aquatic organisms. This study is the first to document the widespread occurrence of SFs and their metabolites in aquatic ecosystems and to elucidate the bioaccumulation potential of SFs in aquatic organisms., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Zhifeng Yang reports financial support was provided by National Natural Science Foundation of China. Zhifeng Yang reports financial support was provided by the Program for Guangdong Introducing Innovative and Entrepreneurial Teams. Zhifeng Yang reports financial support was provided by the Guangdong Provincial Key Laboratory Project. Yanpeng Cai reports financial support was provided by the Guangdong Provincial Key Laboratory Project. Jingchuan Xue reports financial support was provided by the Program for Guangdong Introducing Innovative and Entrepreneurial Teams. Jingchuan Xue reports financial support was provided by Guangzhou Science and Technology project. Jingchuan Xue reports financial support was provided by the Guangdong Provincial Key Laboratory Project., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Microbial lipids, used as taxonomic markers and physiological indicators, have mainly been studied through cultivation. However, this approach is limited due to the scarcity of cultures of environmental microbes, thereby restricting insights into the diversity of lipids and their ecological roles. Addressing this limitation, here we apply metalipidomics combined with metagenomics in the Black Sea, classifying and tentatively identifying 1623 lipid-like species across 18 lipid classes. We discovered over 200 novel, abundant, and structurally diverse sphingolipids in euxinic waters, including unique 1-deoxysphingolipids with long-chain fatty acids and sulfur-containing groups. Sphingolipids were thought to be rare in bacteria and their molecular and ecological functions in bacterial membranes remain elusive. However, genomic analysis focused on sphingolipid biosynthesis genes revealed that members of 38 bacterial phyla in the Black Sea can synthesize sphingolipids, representing a 4-fold increase from previously known capabilities and accounting for up to 25% of the microbial community. These sphingolipids appear to be involved in oxidative stress response, cell wall remodeling, and are associated with the metabolism of nitrogen-containing molecules. Our findings underscore the effectiveness of multi-omics approaches in exploring microbial chemical ecology., (© The Author(s) 2024. Published by Oxford University Press on behalf of the International Society for Microbial Ecology.)

Marine heatwaves (MHWs) have increased in frequency, intensity, and duration in recent years causing significant impacts on marine organisms and fisheries. This study explores the physiological changes of juvenile greater amberjacks (Seriola dumerili) that cope with MHWs. Results showed that physiological parameters were significantly affected by the intensity, duration of MHWs or interaction of two factors (P < 0.05). Repeated MHWs in which water temperatures were increased (24 °C to 28 °C and 32 °C) resulted in changes in enzyme activity levels (catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH)), as well as the level of malondialdehyde (MDA) for antioxidant defense, immune function (acid phosphatase (ACP), alkaline phosphatase (ALP), and lysozyme (LYZ)), and energy metabolism (including triglycerides (TG), glucose (GLU), aspartate aminotransferase (GOT), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and succinate dehydrogenase (SDH)). The activities of enzymes, including those associated with antioxidant defense, immune function, and energy metabolism, changed significantly in relation to short-term MHWs, indicating a thermal stress response. When S. dumerili were exposed to repeated-MHWs, thermal stress responses increased at 28 °C (T28) and decreased at 32 °C (T32). These results exhibited the inability of S. dumerili to acclimate to severe thermal stress from MHWs. This study examined S. dumerili responses to MHWs and assessed the physiological adaptation of juvenile greater amberjacks to MHWs., Competing Interests: Declaration of competing interest No conflicts of interest, financial or otherwise, are declared by the authors., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The recent development of an infrared gas analyzer capable of making carbon dioxide flux measurements from aquatic samples has enabled a new sphere of photosynthesis research. This study details key photosynthesis measurements on four aquatic and hydrophytic species, diverse in their morphology, physiology, and habitat. This guide specifies the methods and procedures needed to make reliable and accurate gas exchange measurements, with examples of data correction and presentation., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Chlorpyrifos (CPF) has been extensively used in the world and frequently found in natural environments, might cause a range of environmental issues and pose a health risk to aquatic species. However, investigation of its toxic effects on offspring after parental exposure has been neglected, especially for aquatic organisms such as fish. In the current study, the effects of chronic CPF exposure (3 and 60 μg/L) on adult zebrafish (F0) was investigated to determine its influence on adult reproductive capacity and offspring (F1 and F2). The results showed the existence of CPF both in F0 ovaries and F1 embryos and larvae, indicating that CPF could be transferred directly from the F0 adult fish to F1 offspring. After 90 d exposure, we observed that F0 female fish showed increased proportion of perinucleolar oocyte in the ovaries, decreased proportion of mature oocyte, and decreased egg production, but not in F1 adult. The transcriptomic analysis revealed that the disruption of metabolism during oocyte maturation in the CPF treatment zebrafish might interfere with F0 oocytes development and quality and ultimately influence offspring survival. For the larvae, the parental CPF exposure distinctly inhibited heart rate at 72 and 120 hpf and increased the mortality of F1 but not F2 larvae. The changes of biochemical indicators confirmed a disturbance in the oxidative balance, induced inflammatory reaction and apoptosis in F1 larvae. Furthermore, the changing profiles of mRNA revealed by RNA-seq confirmed an increased susceptibility in F1 larvae and figured out potential disruptions of ROS metabolism, immune system, apoptosis, and metabolism pathways. Taken together, these results show that chronic CPF treatment can induce reproductive toxicity, and parental transfer of CPF occurs in fish, resulting in transgenerational alters in F1 generation survival and transcription that raising concerns on the ecological risk of CPF in the natural environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

This review delves into the intricate world of Polycyclic Aromatic Hydrocarbons (PAHs) and their bioaccumulation in marine organisms. It explores how physicochemical attributes of individual compounds, along with metabolic oxidation and elimination processes, influence this bioaccumulation. The review further investigates the risks and toxicity associated with PAHs in marine organisms. Subsequently, sediment and water quality guidelines used to assess the potential for adverse effects from PAH exposure are discussed exposing significant differences in the methodological approaches used to establish the guidelines, which can lead to discrepancies in the values used to compare PAH concentrations and limitations to their use. Emphasis is placed on the criteria employed in establishing these guidelines, rooted in adverse effects data linked to PAHs, and efforts to establish local quality guidelines for a tropical area are described. This exploration serves to enhance our understanding of the complex interplay between PAHs and marine ecosystems, informing more effective environmental management strategies., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The metallic pyrithiones are used as antifouling paints for marine vehicles against fouling organisms. However, they are dissolved in marine water and have negative impacts on marine non-target organisms. This study evaluated the adverse effects of sodium pyrithione (NaPT) on Mytilus galloprovincialis using total hemocyte counts (THCs), oxidative stress and antioxidant parameters, and histopathological observations. Mussels were exposed to 0.1 and 1 μg/L NaPT for 96 h. The THC values of the NaPT-exposed mussels significantly decreased (p < 0.05). Lipid peroxidation and advanced oxidative protein products of digestive gland and gill tissues were decreased but only the digestive gland tissues of 0.1 μg/L NaPT values were significantly decreased compared to control groups (p < 0.05). Histological alterations were observed in the gill and the digestive gland tissues revealing malformations and hyperplasia of gill lamella; degenerations and loss of tubules of digestive gland after exposure to NaPT for 96 h. As a result, biocidal sodium pyrithione has adverse effects on the mussels even in short-term exposures and low concentrations., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Pharmaceutical active compounds (PhACs) have raised concerns in the last decade due to their increased consumption and inadequate elimination during discharge, resulting in their introduction into water systems and potential significant threats to non-target organisms. However, few studies have investigated the sublethal impacts of PhAC exposure on marine invertebrates. Thus, the present study aimed to assess tissue-specific responses in Mytilus galloprovincialis to sodium lauryl sulfate (SLS), salicylic acid (SA), and caffeine (CAF) (4.0 mg/L, 4.0 mg/L and 2.0 μg/L, respectively). Short-term in vitro exposures with mussel digestive gland and gill tissues were conducted and biochemical responses related to antioxidant and detoxification capacity, cellular damage and neurotoxicity were assessed. The present results clearly showed significant differences in tissue sensitivity and biochemical responses to the contaminants tested. This study highlights the suitability of filter-feeder species as valuable model organisms for studying the sublethal effects of unintended environmental exposures to PhACs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

All freshwater organisms are challenged to control their internal balance of water and ions in strongly hypotonic environments. We compared the influence of external salinity on the oxygen consumption rates (ṀO2) of three species of freshwater insects, one snail and two crustaceans. Consistent with available literature, we found a clear decrease in ṀO2 with increasing salinity in the snail Elimia sp. and crustaceans Hyalella azteca and Gammarus pulex (r5=-0.90, P=0.03). However, we show here for the first time that metabolic rate was unchanged by salinity in the aquatic insects, whereas ion transport rates were positively correlated with higher salinities. In contrast, when we examined the ionic influx rates in the freshwater snail and crustaceans, we found that Ca uptake rates were highest under the most dilute conditions, while Na uptake rates increased with salinity. In G. pulex exposed to a serially diluted ion matrix, Ca uptake rates were positively associated with ṀO2 (r5=-0.93, P=0.02). This positive association between Ca uptake rate and ṀO2 was also observed when conductivity was held constant but Ca concentration was manipulated (1.7-17.3 mg Ca l-1) (r5=0.94, P=0.05). This finding potentially implicates the cost of calcium uptake as a driver of increased metabolic rate under dilute conditions in organisms with calcified exoskeletons and suggests major phyletic differences in osmoregulatory physiology. Freshwater insects may be energetically challenged by higher salinities, while lower salinities may be more challenging for other freshwater taxa., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

Microalgae and blue mussels are known to accumulate undesirable substances from the environment, including arsenic (As). Microalgae can biotransform inorganic As (iAs) to organoarsenic species, which can be transferred to blue mussels. Knowledge on As uptake, biotransformation, and trophic transfer is important with regards to feed and food safety since As species have varying toxicities. In the current work, experiments were conducted in two parts: (1) exposure of the microalgae Diacronema lutheri to 5 and 10 μg/L As(V) in seawater for 4 days, and (2) dietary As exposure where blue mussels (Mytilus edulis L.) were fed with D. lutheri exposed to 5 and 10 μg/L As(V), or by aquatic exposure to 5 μg/L As(V) in seawater, for a total of 25 days. The results showed that D. lutheri can take up As from seawater and transform it to methylated As species and arsenosugars (AsSug). However, exposure to 10 μg/L As(V) resulted in accumulation of iAs in D. lutheri and lower production of methylated As species, which may suggest that detoxification mechanisms were overwhelmed. Blue mussels exposed to As via the diet and seawater showed no accumulation of As. Use of linear mixed models revealed that the blue mussels were gradually losing As instead, which may be due to As concentration differences in the mussels' natural environment and the experimental setup. Both D. lutheri and blue mussels contained notable proportions of simple methylated As species and AsSug. Arsenobetaine (AB) was not detected in D. lutheri but present in minor fraction in mussels. The findings suggest that low-trophic marine organisms mainly contain methylated As species and AsSug. The use of low-trophic marine organisms as feed ingredients requires further studies since AsSug are regarded as potentially toxic, which may introduce new risks to feed and food safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Ocean acidification (OA) and trace metal pollutants coexist to exert combined effects on the functions and services of marine ecosystems. Increasing atmospheric carbon dioxide has caused a decrease in the pH of the ocean, affecting the bioavailability and speciation of trace metals and consequently altering metal toxicity in marine organisms. As an important trace metal functioned in hemocyanin, the richness of Copper (Cu) in octopuses is remarkable. Therefore, the biomagnification and bioaccumulation capacities of Cu in octopuses may be a non-negligible risk of contamination. Here, Amphioctopus fangsiao was continuously exposed to acidified seawater (pH 7.8) and copper (50 μg/L) to investigate the combined effect of ocean acidification and Cu exposure on marine mollusks. Our results showed that A. fangsiao could adapt well to ocean acidification after 21 days of the rearing experiment. However, the accumulation of Cu in A. fangsiao intestine increased significantly in acidified seawater under high levels of Cu stress. In addition, Cu exposure can influence the physiological function of A. fangsiao, including growth and feeding. This study also demonstrated that Cu exposure disturbed glucolipid metabolism and induced oxidative damage to intestine tissue, and ocean acidification further exacerbated these toxic effects. The obvious histological damage and microbiota alterations were also caused by Cu stress and its combined effect with ocean acidification. At the transcription level, we found numerous differentially expressed genes (DEGs) and significantly enriched KEGG pathways, involving glycolipid metabolism, transmembrane transport, glucolipid metabolism, oxidative stress, mitochondrial, protein and DNA damage, all revealing the strong toxicological synergetic effect of Cu and OA exposure and the molecular adaptation mechanism of A. fangsiao. Collectively, this study demonstrated that octopuses may withstand future ocean acidification conditions, however, the complex interactions of future OA and trace metal pollution need to be emphasized. OA can influence the toxicity of trace metals, inducing a potential threat to marine organism safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Organophosphorus pesticides (OPPs) are widely used in agricultural production due to their chemical stability, high efficiency and low cost. It should be emphasized that OPPs can seriously harm aquatic organisms after entering the water environment through leaching and other ways. To this end, this review combines a new method to quantitatively visualize and summarize information on developments in this field to review the latest progress in OPPs toxicity, propose scientific trends and research hotspots. Among all countries, China and the United States have published a large number of articles and played a leading role. Based on the detection of co-occurrence keywords, it is emphasized that "OPPs cause oxidative stress in organisms", which reflects that the main factor of OPPs toxicity is the occurrence of oxidative stress. Researchers also focused on studies involving AchE activity, acute toxicity and mixed toxicity. This reveals that OPPs mainly affect the nervous system, and higher organisms are more resistant to the toxic effects of OPPs than lower organisms due to their strong metabolic capacity. As for the mixed toxicity of OPPs, most OPPs have synergistic toxic effects. Moreover, the analysis of keyword bursts revealed that the study of OPPs on the immune response of aquatic organisms and the effect of temperature on toxicity will become new research trends. In conclusion, this scientometric analysis can provide a scientific basis for improving the aquatic ecological environment and rationally using OPPs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Vitamin B1 (thiamin) is a vital nutrient for most cells in nature, including marine plankton. Early and recent experiments show that B1 degradation products instead of B1 can support the growth of marine bacterioplankton and phytoplankton. However, the use and occurrence of some degradation products remains uninvestigated, namely N-formyl-4-amino-5-aminomethyl-2-methylpyrimidine (FAMP), which has been a focus of plant oxidative stress research. We investigated the relevance of FAMP in the ocean. Experiments and global ocean meta-omic data indicate that eukaryotic phytoplankton, including picoeukaryotes and harmful algal bloom species, use FAMP while bacterioplankton appear more likely to use deformylated FAMP, 4-amino-5-aminomethyl-2-methylpyrimidine. Measurements of FAMP in seawater and biomass revealed that it occurs at picomolar concentrations in the surface ocean, heterotrophic bacterial cultures produce FAMP in the dark-indicating non-photodegradation of B1 by cells, and B1-requiring (auxotrophic) picoeukaryotic phytoplankton produce intracellular FAMP. Our results require an expansion of thinking about vitamin degradation in the sea, but also the marine B1 cycle where it is now crucial to consider a new B1-related compound pool (FAMP), as well as generation (dark degradation-likely via oxidation), turnover (plankton uptake), and exchange of the compound within the networks of plankton. IMPORTANCE Results of this collaborative study newly show that a vitamin B1 degradation product, N-formyl-4-amino-5-aminomethyl-2-methylpyrimidine (FAMP), can be used by diverse marine microbes (bacteria and phytoplankton) to meet their vitamin B1 demands instead of B1 and that FAMP occurs in the surface ocean. FAMP has not yet been accounted for in the ocean and its use likely enables cells to avoid B1 growth deficiency. Additionally, we show FAMP is formed in and out of cells without solar irradiance-a commonly considered route of vitamin degradation in the sea and nature. Altogether, the results expand thinking about oceanic vitamin degradation, but also the marine B1 cycle where it is now crucial to consider a new B1-related compound pool (FAMP), as well as its generation (dark degradation-likely via oxidation), turnover (plankton uptake), and exchange within networks of plankton., Competing Interests: The authors declare no conflict of interest.

Gluconeogenesis (GNG) is the process of regenerating glucose and NAD+ that allows for continued ATP synthesis by glycolysis during fasting or in hypoxia. Recent data from C. elegans and crustaceans challenged with hypoxia show differential and tissue-specific expression of GNG-specific genes. Here we report differential expression of several GNG-specific genes in the head and body of a model organism, Daphnia magna, a planktonic crustacean, in normoxic and acute hypoxic conditions. We predict that GNG-specific transcripts will be enriched in the body, where most of the fat tissue is located, rather than in the head, where the tissues critical for survival in hypoxia, the central nervous system and locomotory muscles, are located. We measured the relative expression of GNG-specific transcripts in each body part by qRT-PCR and normalized them by either the expression of a reference gene or the rate-limiting glycolysis enzyme pyruvate kinase (PK). Our data show that of the three GNG-specific transcripts tested, pyruvate carboxylase (PC) showed no differential expression in either the head or body. Phosphoenolpyruvate carboxykinase (PEPCK-C), on the other hand, is upregulated in hypoxia in both body parts. Fructose-1,6-bisphosphatase (FBP) is upregulated in the body relative to the head and upregulated in hypoxia relative to normoxia, with a stronger body effect in hypoxia when normalized by PK expression. These results support our hypothesis that Daphnia can survive hypoxic conditions by implementing the Cori cycle, where body tissues supply glucose and NAD+ to the brain and muscles, enabling them to continuously generate ATP by glycolysis., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Malek et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Environmental epigenetics has become a key research focus in global climate change studies and environmental pollutant investigations impacting aquatic ecosystems. Specifically, triggered by environmental stress conditions, intergenerational DNA methylation changes contribute to biological adaptive responses and survival of organisms to increase their tolerance towards these conditions. To critically review epigenetic analytical approaches in ecotoxicological aquatic research, we evaluated 78 publications reported over the past five years (2016-2021) that applied these methods to investigate the responses of aquatic organisms to environmental changes and pollution. The results show that DNA methylation appears to be the most robust epigenetic regulatory mark studied in aquatic animals. As such, multiple DNA methylation analysis methods have been developed in aquatic organisms, including enzyme restriction digestion-based and methyl-specific immunoprecipitation methods, and bisulfite (in)dependent sequencing strategies. In contrast, only a handful of aquatic studies, i.e. about 15%, have been focusing on histone variants and post-translational modifications due to the lack of species-specific affinity based immunological reagents, such as specific antibodies for chromatin immunoprecipitation applications. Similarly, ncRNA regulation remains as the least popular method used in the field of environmental epigenetics. Insights into the opportunities and challenges of the DNA methylation and histone variant analysis methods as well as decreasing costs of next generation sequencing approaches suggest that large-scale epigenetic environmental studies in model and non-model organisms will soon become available in the near future. Moreover, antibody-dependent and independent methods, such as mass spectrometry-based methods, can be used as an alternative epigenetic approach to characterize global changes of chromatin histone modifications in future aquatic research. Finally, a systematic guide for DNA methylation and histone variant methods is offered for ecotoxicological aquatic researchers to select the most relevant epigenetic analytical approach in their research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)