Temperature and nutrients drive distinct successions between diatoms and dinoflagellates over the past 40 years: Implications for climate warming and eutrophication.

Diatoms and dinoflagellates are two typical functional groups of phytoplankton, playing important roles in ecosystem processes and biogeochemical cycles. Changes in diatoms and dinoflagellates are thought to be one of the possible mechanisms for the increase in harmful algal blooms (HABs), due to changing hydrological conditions associated with climate change and human activities. However, little is known about their ability to adapt to changing ocean environments, thus making it difficult to know whether and how they are adapting. By analyzing a 44-year monitoring dataset in the central Bohai Sea during 1978-2021, we found that the abundance ratio of diatoms to dinoflagellates showed a decreasing trend seasonally and ecologically, indicating that the phytoplankton community underwent distinct successional processes from diatom dominance to diatom-dinoflagellate co-dominance. These processes exhibited varying responses to temperature, nutrient concentrations and ratios, and their interactions, of which temperature primarily drove the seasonal succession whereas nutrients were responsible for the ecological succession. Specifically, diatoms showed a preference for lower temperatures and higher DIP concentrations, and were able to tolerate lower DIN at lower temperatures. In contrast, dinoflagellates tended to prevail at conditions of warming and high N/P ratios. These different traits of diatoms and dinoflagellates reflected the fact that warming as a result of rising temperature and eutrophication as a consequence of nutrient input would favor dinoflagellates over diatoms. Moreover, the increasing dominance of dinoflagellates indicated that dinoflagellate blooms were likely to become more frequent and intense in the central Bohai Sea.

The incorporation of strontium and barium into the otoliths of the flounder Paralichthys olivaceus at early life stages demonstrates resilience to ocean acidification.

Ocean acidification could modify the bioavailability and chemical properties of trace elements in seawater, which could affect their incorporation into the calcareous structures of marine organisms. Fish otoliths, biomineralized ear stones made by aragonite, are suspended within the endolymph fluid of teleosts, indicating that the elemental incorporation of otoliths might also be susceptible to ocean acidification. In this study, we evaluated the combined effects of CO2-induced ocean acidification (pH 8.10, 7.70, and 7.30, corresponding to ocean acidification scenarios under the representative concentration pathway 8.5 model as projected by the Intergovernmental Panel on Climate Change) and water elemental concentrations of strontium (Sr) and barium (Ba; low, medium, and high) on elemental incorporation into otoliths of the flounder Paralichthys olivaceus at early life stages. Our results revealed that the elemental incorporation of Sr and Ba into otoliths was principally dependent on the corresponding water elemental concentrations rather than on ocean acidification. Moreover, the partition coefficients (DMe) of Sr and Ba may stabilize after dynamic equilibrium is reached as the water elemental concentration increases, but are not affected by ocean acidification. Therefore, the incorporation of Sr and Ba into otoliths of the flounder at early life stages may not serve as an effective indicator of ocean acidification. In other words, the findings suggest that ocean acidification does not impact the incorporation of Sr and Ba incorporation into otoliths when tracing the temperature or salinity experiences of the flounder. Our findings will provide new knowledge for understanding the potential ecological effects of ocean acidification on the recruitment dynamics of fish species.

Global prevalence of microplastics in tap water systems: Abundance, characteristics, drivers and knowledge gaps.

Tap water is a main route for human direct exposure to microplastics (MPs). This study recompiled baseline data from 34 countries to assess the current status and drivers of MP contamination in global tap water systems (TWS). It was shown that MPs were detected in 87 % of 1148 samples, suggesting the widespread occurrence of MPs in TWS. The detected concentrations of MPs spanned seven orders of magnitude and followed the linearized log-normal distribution (MSE = 0.035, R2 = 0.965), with cumulative concentrations at 5th, 50th and 95th percentiles of 0.028, 4.491 and 728.105 items/L, respectively. The morphological characteristics were further investigated, indicating that particles smaller than 50 µm dominated in global TWS, with fragment, polyester and transparent as the most common shape, composition and color of MPs, respectively. Subsequently, the SHapley Additive exPlanations (SHAP) algorithm was implemented to quantify the importance of variables affecting the MP abundance in global TWS, showing that the lower particle size limit was the most important variables. Subgroup analysis revealed that the concentration of MPs counted at the size limit of 1 µm was >20 times higher than that above 1 µm. Ultimately, current knowledge gaps and future research needs were elucidated.

Multiple Dense Papules on the Entire Glans: Profound Pearly Penile Papules.

A 23-year-old man presented for evaluation of multiple dense asymptomatic papules on the entire glans. Histologically, the lesions resembled acral angiofibroma. A diagnosis of profound pearly penile papules was made. This is the third reported case and more serious and typical than described in previous reports.

Renal metabolomic profiling of large yellow croaker Larimichthys crocea acclimated in low salinity waters.

Cultivation of Larimichthys crocea in low salinity water has been regarded as an effective way to treat diseases induced by pathogens in seawater. The kidney of euryhaline teleost plays important roles in not only osmoregulation but also regulation of intermediary metabolism. However, the renal responses of metabolism and osmoregulation in L. crocea to low salinity waters are still rarely reported. In this work, renal metabolomic analysis based on MS technique was conducted on the L. crocea following cultivation in salinities of 24, 8, 6, 4, and 2 ppt for 40 days. A total of 485 metabolites covering organic acids and derivatives (34.17 %), lipids and lipid-like molecules (17.55 %), organoheterocyclic compounds (12.22 %), nucleosides, nucleotides, and analogues (11.91 %), and organic oxygen compounds (10.97 %), were identified in L. crocea kidney. Compared with control group (salinity 24), nearly all amino acids, nucleotides, and their derivatives were decreased in the kidney of L. crocea, whereas most of lipid-related metabolites including phospholipid, glycerophospholipids, and fatty acids were increased. The decrease in urea and inorganic ions as well as TMAO, betaine and taurine in L. crocea kidney suggested the less demand for maintaining osmotic homeostasis. Several intermediary metabolites covering amino acids, TCA cycle intermediates, and fatty acids were also significantly changed to match with the shift of energy allocation from osmoregulation to other biological processes. The reduced energy demand for osmoregulation might contribute to the promotion of L. crocea growth under low salinity environment. What is more, carbamoylphosphate and urea that showed linear salinity response curves and higher ED50 values were potential biomarkers to adaptation to low salinity water. Overall, the characterization of metabolomes of L. crocea kidney under low salinity provided a better understanding of the adaptive mechanisms to low salinity water and potentially contributed to a reference for optimal culture salinity and feed formula of L. crocea culture in low salinity water.

Inbreeding evaluation using microsatellite confirmed inbreeding depression in growth in the Fenneropenaeus chinensis natural population.

Understanding inbreeding depressions (IBDs), the effect on the phenotypic performance of inbreeding, is of major importance for evolution and conservation genetics. Inbreeding depressions in aquatic animals were well documented in a domestic or captive population, while there is less evidence of inbreeding depression in natural populations. Chinese shrimp, Fenneropenaeus chinensis, is an important species in both aquaculture and fishery activities in China. To investigate inbreeding depression in natural populations, four Fenneropenaeus chinensis natural populations (Huanghua, Qinhuangdao, Qingdao, and Haiyang) were collected from the Bohai and Yellow seas. Microsatellite markers were used to evaluate individual inbreeding coefficients (F) of all samples. Furthermore, the effects of inbreeding on growth traits were investigated. The results showed marker-based F was continuous and ranged from 0 to 0.585, with an average of 0.191 ± 0.127, and there was no significant difference among the average F of the four populations. Regression analysis using the four populations showed inbreeding had a very significant (p < 0.01) effect on body weight. When analyzing a single population, regression coefficients were also all negative and those in Huanghua and in Qingdao were significant at the level of p < 0.05 and < 0.01, respectively. Inbreeding depressions, expressed as the percent change in body weight per 10% increase in F, were 2.75% in Huanghua, 2.22% in Qingdao, and 3.69% in all samples. This study provided a piece of rare evidence of inbreeding depression in natural populations and also guidance toward the conservation of wild Fenneropenaeus chinensis resources.

The legacy effect of microplastics on aquatic animals in the depuration phase: Kinetic characteristics and recovery potential.

The prevalence of microplastics (MPs) in global aquatic environments has received considerable attention. Currently, concerns have been raised regarding reports that the adverse effect of MPs on aquatic animals in the exposure phase may not be (completely) reversed in the depuration phase. In order to provide insights into the legacy effect of MPs from the depuration phase, this study evaluated the kinetic characteristics and recovery potential of aquatic animals after the exposure to MPs. More specifically, a total of 68 depuration kinetic curves were highly fitted to estimate the retention time of MPs. It was shown that the retention time ranged from 1.26 to 3.01 days, corresponding to the egestion of 90 % to 99 % of ingested MPs. The retention time decreased with the increased retention rate. Furthermore, variables potentially affecting the retention time were ranked by the decision tree-based eXtreme Gradient Boosting (XGBoost) algorithm, suggesting that the particle size and tested species were of great importance for explaining the difference in retention time of MPs. Moreover, a biomarker profile was recompiled to determine the toxic changes. Results indicated that the MPs-induced toxicity significantly reduced in the depuration phase, evidenced by the recovery of energy reserves and metabolism, hepatotoxicity, immunotoxicity, hematological parameters, neurotoxicity and oxidative stress. However, the continuous detoxification and remarkable genotoxicity implied that the toxicity was not completely alleviated. In addition, the current knowledge gaps are also highlighted, with recommendations proposed for future research.

DEB-IBM for predicting climate change and anthropogenic impacts on population dynamics of hairtail Trichiurus lepturus in the East China Sea.

The hairtail Trichiurus lepturus supports the largest fisheries in the East China Sea. The stock has fluctuated in the past few decades and this variation has been attributed to human pressures and climate change. To investigate energetics of individuals and population dynamics of the species in responses to environmental variations and fishing efforts, we have developed a DEB-IBM by coupling a dynamic energy budget (DEB) model to an individual-based model (IBM). The parameter estimation of DEB model shows an acceptable goodness of fit. The DEB-IBM was validated with histological data for a period of 38 years. High fishing pressure was largely responsible for the dramatic decline of the stock in middle 1980s. The stock recovered from early 1990s, which coincided with introduction of fishing moratorium on spawning stocks in inshore waters and substantial decrease of fishing efforts from large fisheries companies. In addition, the population average age showed a trend of slight decrease. The model successfully reproduced these observations of interannual variations in the population dynamics. The model was then implemented to simulate the effect of climate change on the population performance under greenhouse gas emission scenarios projected for 2100. It was also used to explore population responses to changing fishing mortalities. These scenario simulations have shown that the population biomass under SSP1-1.9, SSP2-4.5 and SSP5-8.5 would decline by 7.5%, 16.6% and 30.1%, respectively, in 2100. The model predicts that increasing fishing mortality by 10% will cause 5.3% decline of the population biomass, whereas decrease of fishing mortality by 10% will result in 6.8% increase of the biomass. The development of the DEB-IBM provides a predictive tool to inform management decisions for sustainable exploitation of the hairtail stock in the East China Sea.

Marine litter on the seafloors of the Bohai Sea, Yellow Sea and northern East China Sea.

Seafloor litter was investigated in the Bohai Sea, Yellow Sea, and northern East China Sea (BYnECS) based on fisheries-independent bottom trawl surveys in 2019. The mean density of seafloor litter was 48.44 items∙km-2 (44.56 kg∙km-2) in the BYnECS, which was at an intermediate level compared with the values observed in other continental shelf areas worldwide. There were significant differences in the density of seafloor litter among different regions (P < 0.05), and the high-density litter accumulation areas in the northern Yellow Sea and Changjiang estuary and adjacent waters were close to the sediment accumulation areas. Plastics were predominant in the BYnECS and accounted for 72.80%/44.05% (number/weight) of the seafloor litter. Fishery-related litter was the main source of seafloor litter in the BYnECS. This study systematically reports the density, composition, sources and spatial distribution of seafloor litter in the BYnECS, thereby providing a scientific basis for the management of marine litter.

Is seafloor litter contributing to sea anemone blooms?

Increasing marine litter have become a global environmental disaster. The accumulation of seafloor litter (generally includes anthropogenic litter and natural debris) could change the habitat of benthic organisms and thereby affecting their population dynamics including spatial distribution. Metridium senile fimbriatum (i.e., M. senile), a fast-growing sea anemone, has become a dominant species of benthic community in the north Yellow Sea in recent years. In this study, we tested the hypothesis that the distribution of M. senile is positively correlated with that of seafloor litter, using data collected on seafloor litter and M. senile from three fisheries-independent bottom trawl surveys in the Yellow Sea in May, August and November 2019. Gradient Forest Model (GFM) was used to select appropriate response variables for characterizing the distribution of M. senile, and evaluate the influences of potential environmental factors on M. senile distribution. Surface area of anthropogenic litter (represented as 'Anthropogenic litter'), surface area of natural debris (represented as 'Natural debris') and latitude (Lat) were identified as the most significant variables influencing the distribution of M. senile. Furthermore, Generalized Additive Mixed Model (GAMM) was applied to model the abundance distribution of M. senile in terms of significant environmental variables, and evaluate its correlations with 'Anthropogenic litter' and 'Natural debris'. The best fitting GAMM showed that the abundance of M. senile has a significantly positive association with 'Anthropogenic litter' and 'Natural debris'. We therefore speculated that accumulation of seafloor litter might contribute to the bloom of M. senile, given that seafloor litter could serve as "vectors" for M. senile dispersal and provide with a preferable "natural habitat" for their settlement.

Proteomic analysis revealed gender-specific responses of mussels (Mytilus galloprovincialis) to trichloropropyl phosphate (TCPP) exposure.

Trichloropropyl phosphate (TCPP) is a halogenated organophosphate ester that is widely used as flame retardants and plasticizers. In this study, gender-specific accumulation and responses in mussel Mytilus galloprovincialis to TCPP exposure were focused and highlighted. After TCPP (100 nmol L-1) exposure for 42 days, male mussels showed similar average bioaccumulation (37.14 ± 6.09 nmol g-1 fat weight (fw)) of TCPP with that in female mussels (32.28 ± 4.49 nmol g-1 fw). Proteomic analysis identified 219 differentially expressed proteins (DEPs) between male and female mussels in control group. There were 52 and 54 DEPs induced by TCPP in male and female mussels, respectively. Interestingly, gender-specific DEPs included 37 and 41 DEPs induced by TCPP in male and female mussels, respectively. The proteomic differences between male and female mussels were related to protein synthesis and degradation, energy metabolism, and functions of cytoskeleton and motor proteins. TCPP influenced protein synthesis, energy metabolism, cytoskeleton functions, immunity, and reproduction in both male and female mussels. Protein-protein interaction (PPI) networks indicated that protein synthesis and energy metabolism were the main biological processes influenced by TCPP. However, DEPs involved in these processes and their interaction patterns were quite different between male and female mussels. Basically, twelve ribosome DEPs which directly or indirectly interacted were found in protein synthesis in TCPP-exposed male mussels, while only 3 ribosome DEPs (not interacted) in TCPP-exposed female mussels. In energy metabolism, only 4 DEPs (with the relatively simple interaction pattern) mainly resided in fatty acid metabolism, butanoate/propanoate metabolism and glucose metabolism were discovered in TCPP-exposed male mussels, and more DEPs (with multiple interactions) functioned in TCA cycle and pyruvate/glyoxylate/dicarboxylate metabolism were found in TCCP-exposed female mussels. Taken together, TCPP induced gender-specific toxicological effects in mussels, which may shed new lights on further understanding the toxicological mechanisms of TCPP in aquatic organisms.

Evaluation on the biomagnification or biodilution of trace metals in global marine food webs by meta-analysis.

The transmission and accumulation of trace metals in marine food webs have a profound influence on the structure and function of marine environment. In order to quantitatively assess the trophic transfer behaviors of eight common metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in simplified five-trophic level marine food webs, a total of 9929 biological samples from 61 studies published between 2000 and 2019, involving 154 sampling sites of 33 countries/regions, were re-compiled using meta-analysis. Based on concentration-trophic level weighted linear regression and predator/prey comparison, the food web magnification factor (FWMF) and the biomagnification factor (BMF) were calculated, respectively. The results showed dissimilar trophic transfer behaviors of these metals in global marine food webs, in which As and Ni tended to be efficiently biodiluted with increasing trophic levels (FWMFs < 1, p < 0.01), while Hg, Pb and Zn trophically biomagnified (FWMFs > 1, p < 0.05). However, Cd, Cr and Cu presented no biomagnification or biodilution trend (p > 0.05). The values of FWMFs were ranked as: Hg (2.01) > Pb (1.81) > Zn (1.15) > Cu (1.13) > Cr (0.951) > Cd (0.850) > Ni (0.731) > As (0.494). In terms of specific predator-prey relationship, Pb showed significant biodilution from tertiary consumers (TC) to top predators (BMF < 1, p < 0.05), whereas Cd and Cu displayed obvious biomagnification from primary consumers (PC) to secondary consumers (SC) (BMFs >1, p < 0.05). Additionally, when Cu and Zn were transferred from SC to TC, and primary producers to PC, clear biodilution and biomagnification effects were observed, respectively (p < 0.05). Further analysis indicated that the average concentration of Hg in five-trophic level marine food webs of developed countries (0.904 mg kg-1 dw) was more noticeable (p < 0.05) than that of developing countries (0.549 mg kg-1 dw).

Global responses to tris(1-chloro-2-propyl)phosphate (TCPP) in rockfish Sebastes schlegeli using integrated proteomic and metabolomic approach.

As alternatives of brominated flame retardants, organophosphate flame retardants (OPFRs) can be detected in multiple marine environmental media. Tris(1-chloro-2-propyl)phosphate (TCPP) was one of the most frequently and abundantly detected OPFRs in the Bohai Sea. Exposure to TCPP has been shown to induce abnormal behavior in zebrafish as well as neurotoxicity in Caenorhabditis elegans. However, there is a lack of mechanism investigations on the toxic effects of TCPP at molecular levels. In this work, proteomics and metabolomics were integrated to analyze the proteome and metabolome responses in rockfish Sebastes schlegeli treated with TCPP (10 and 100 nM) for 15 days. A total of 143 proteins and 8 metabolites were significantly altered in rockfish following TCPP treatments. The responsive proteins and metabolites were predominantly involved in neurotransmission, neurodevelopment, signal transduction, cellular transport, cholesterol metabolism, bile acid synthesis, and detoxification. Furthermore, a hypothesized network of proteins, metabolites, and pathways in rockfish was summarized based on the combination of proteomic and metabolomic results, showing some key molecular events in response to TCPP. Overall, the present study unraveled the molecular responses at protein and metabolite levels, which provided a better understanding of toxicological effects and mechanisms of TCPP in marine teleost.

Marine seafood production via intense exploitation and cultivation in China: Costs, benefits, and risks.

Identifying strategies to maintain seafood supply is central to global food supply. China is the world's largest producer of seafood and has used a variety of production methods in the ocean including domestic capture fisheries, aquaculture (both freshwater and marine), stock enhancement, artificial reef building, and distant water fisheries. Here we survey the outcomes of China's marine seafood production strategies, with particular attention paid to the associated costs, benefits, and risks. Benefits identified include high production, low management costs, and high employment, but significant costs and risks were also identified. For example, a majority of fish in China's catches are one year-old, ecosystem and catch composition has changed relative to the past, wild and farmed stocks can interact both negatively and positively, distant water fisheries are a potential source of conflict, and disease has caused crashes in mariculture farms. Reforming China's wild capture fisheries management toward strategies used by developed nations would continue to shift the burden of production to aquaculture and could have negative social impacts due to differences in fishing fleet size and behavior, ecosystem structure, and markets. Consequently, China may need to develop novel management methods in reform efforts, rather than rely on examples from other large seafood producing countries. Improved accounting of production from fisheries and aquaculture, harmonization and centralization of historical data sets and systematic scientific surveys would improve the knowledge base for planning and evaluating future reform.

Evaluation of metal pollution-induced biological effects in Chinese shrimp Fenneropenaeus chinensis by NMR-based metabolomics.

Metal pollution in Laizhou Bay along the Bohai Sea in China has been posing a risk on fishery species and hence may affect seafood quality. In this work, shrimps Fenneropenaeus chinensis were sampled from three sites, namely, a reference (site 6334) and two metal-polluted (sites 6262 and 7262) sites, located in Laizhou Bay. The metal concentrations in shrimp muscle tissues were tested using the ICP-MS technique. The Cr and Cu concentrations were the highest in the shrimp samples from site 7262, exceeding the national seafood safety standard Ⅱ, and the As concentration was much higher than the national seafood safety standard Ⅲ. NMR-based metabolomics indicated that metal pollution induced oxidative and immune stresses, damaged the muscular structure, and disrupted energy metabolism in shrimps at sites 6262 and 7262, in particular disturbed osmotic regulation in shrimps at site 7262. Glycine and serine could serve as biomarkers for Cd in F. chinensis.

iTRAQ-based proteomic analysis on the mitochondrial responses in gill tissues of juvenile olive flounder Paralichthys olivaceus exposed to cadmium.

Cadmium (Cd) is an important heavy metal pollutant in the Bohai Sea. Mitochondria are recognized as the key target for Cd toxicity. However, mitochondrial responses to Cd have not been fully investigated in marine fishes. In this study, the mitochondrial responses were characterized in gills of juvenile flounder Paralichthys olivaceus treated with two environmentally relevant concentrations (5 and 50 µg/L) of Cd for 14 days by determination of mitochondrial membrane potential (MMP), observation of mitochondrial morphology and quantitative proteomic analysis. Both Cd treatments significantly decreased MMPs of mitochondria from flounder gills. Mitochondrial morphologies were altered in Cd-treated flounder samples, indicated by more and smaller mitochondria. iTRAQ-based proteomic analysis indicated that a total of 128 proteins were differentially expressed in both Cd treatments. These proteins were basically involved in various biological processes in gill mitochondria, including mitochondrial morphology and import, tricarboxylic acid (TCA) cycle, oxidative phosphorylation (OXPHOS), primary bile acid biosynthesis, stress resistance and apoptosis. These results indicated that dynamic regulations of energy homeostasis, cholesterol metabolism, stress resistance, apoptosis, and mitochondrial morphology in gill mitochondria might play significant roles in response to Cd toxicity. Overall, this study provided a global view on mitochondrial toxicity of Cd in flounder gills using iTRAQ-based proteomics.

Toxicological effects of As (V) in juvenile rockfish Sebastes schlegelii by a combined metabolomic and proteomic approach.

Arsenic (As) is a metalloid element that is ubiquitous in the marine environment and its contamination has received worldwide attention due to its potential toxicity. Arsenic can induce multiple adverse effects, such as lipid metabolism disorder, immune system dysfunction, oxidative stress and carcinogenesis, in animals. Inorganic arsenic includes two chemical forms, arsenite (As (III)) and arsenate (As (V)), in natural environment. As (V) is the dominant form in natural waters. In the present study, metabolomic and proteomic alterations were investigated in juvenile rockfish Sebastes schlegelii exposed to environmentally relevant concentrations of As (V) for 14 d. The analysis of iTRAQ-based proteomics combined with untargeted NMR-based metabolomics indicated apparent toxicological effects induced by As (V) in juvenile rockfish. In details, the metabolites, including lactate, alanine, ATP, inosine and phosphocholine were significantly altered in As-treated groups. Proteomic responses suggested that As (V) could not only affected energy and primary metabolisms and signal transduction, but also influenced cytoskeleton structure in juvenile rockfish. This work suggested that the combined proteomic and metabolomic approach could shed light on the toxicological effects of pollutants in rockfish S. schlegelii.

Evaluation of mitochondrial toxicity of cadmium in clam Ruditapes philippinarum using iTRAQ-based proteomics.

Cadmium is one of the most serious metal pollutants in the Bohai Sea. Previous studies revealed that mitochondrion might be the target organelle of Cd toxicity. However, there is a lack of a global view on the mitochondrial responses in marine animals to Cd. In this work, the mitochondrial responses were characterized in clams Ruditapes philippinarum treated with two concentrations (5 and 50 µg/L) of Cd for 5 weeks using tetraethylbenzimidazolylcarbocyanine iodide (JC-1) staining, ultrastructural observation and quantitative proteomic analysis. Basically, a significant decrease of mitochondrial membrane potential (△Ψm) was observed in clams treated with the high concentration (50 µg/L) of Cd. Cd treatments also induced specific morphological changes indicated by elongated mitochondria. Furthermore, iTRAQ-based mitochondrial proteomics showed that a total of 97 proteins were significantly altered in response to Cd treatment. These proteins were closely associated with multiple biological processes in mitochondria, including tricarboxylic acid (TCA) cycle, oxidative phosphorylation, fatty acid ß-oxidation, stress resistance and apoptosis, and mitochondrial fission. These findings confirmed that mitochondrion was one of the key targets of Cd toxicity. Moreover, dynamical regulations, such as reconstruction of energy homeostasis, induction of stress resistance and apoptosis, and morphological alterations, in mitochondria might play essential roles in Cd tolerance. Overall, this work provided a deep insight into the mitochondrial toxicity of Cd in clams based on a global mitochondrial proteomic analysis.

Morphology and genome of a snailfish from the Mariana Trench provide insights into deep-sea adaptation.

It is largely unknown how living organisms-especially vertebrates-survive and thrive in the coldness, darkness and high pressures of the hadal zone. Here, we describe the unique morphology and genome of Pseudoliparis swirei-a recently described snailfish species living below a depth of 6,000 m in the Mariana Trench. Unlike closely related shallow sea species, P. swirei has transparent, unpigmented skin and scales, thin and incompletely ossified bones, an inflated stomach and a non-closed skull. Phylogenetic analyses show that P. swirei diverged from a close relative living near the sea surface about 20 million years ago and has abundant genetic diversity. Genomic analyses reveal that: (1) the bone Gla protein (bglap) gene has a frameshift mutation that may cause early termination of cartilage calcification; (2) cell membrane fluidity and transport protein activity in P. swirei may have been enhanced by changes in protein sequences and gene expansion; and (3) the stability of its proteins may have been increased by critical mutations in the trimethylamine N-oxide-synthesizing enzyme and hsp90 chaperone protein. Our results provide insights into the morphological, physiological and molecular evolution of hadal vertebrates.

Differential biological effects in two pedigrees of clam Ruditapes philippinarum exposed to cadmium using iTRAQ-based proteomics.

Due to the industrial discharges, cadmium (Cd) has been one of typical heavy metal pollutants in the Bohai Sea. Manila clam Ruditapes philippinarum is frequently used for pollution biomonitoring and consists of several pedigrees, of which White and Zebra clams are the dominant pedigrees along the Bohai Sea coast. However, limited attention has been paid on the differential biological effects in different pedigrees of clam to heavy metals. In this work, the proteome profiling analysis was performed to reveal the differential proteomic responses in White and Zebra clams to Cd exposure (200 µg/L) for 48 h, followed by bioinformatical analysis. The proteomic investigations showed that Cd treatment induced more differentially expressed proteins (DEPs) in White clam samples than in Zebra clam samples. Based on the DEPs, we found that some key biological processes consisting of immune response and metabolism were commonly induced in both two pedigrees of clam. Uniquely, some processes related to cellular signaling, proteolysis and energy production were enhanced in Cd-treated White clam samples. Comparatively, the depletion in some unique processes on proteolysis and energy production was elicited in Cd-treated Zebra clam samples, as well as disorder in gene expression. Moreover, Cd exposure caused increases in CAT and POD activities in White clam samples and decreases in SOD and CAT activities in Zebra clams samples, which were consistent with the proteomic responses. Overall, these findings confirmed the differential biological effects of White and Zebra clams to Cd treatment, suggesting that the pedigree of animal should be taken into consideration in ecotoxicology studies.