Hull-cleaning wastewater poses serious acute and chronic toxicity to a marine mysid-A multigenerational study

We conducted a comprehensive assessment involving acute effects on 96-hour survival and biochemical parameters, as well as chronic effects on growth and reproduction spanning three generations of the marine mysid Neomysis awatschensis exposed to filtered wastewater to evaluate the potential impact of ship hull-cleaning wastewater on crustaceans. The analyzed wastewater exhibited elevated concentrations of metals, specifically zinc (Zn) and copper (Cu) and metal-based antifoulants, i.e., Cu pyrithoine (CuPT) and Zn pyrithoine (ZnPT). The results revealed dose-dependent reductions in survival rates, accompanied by a notable increase in oxidative stress, in response to the sublethal values of two wastewater samples: 1) mechanically filtered using the cleaning system (MF) and 2) additionally filtered in the laboratory (LF) for 96 h. Mysids exposed to MF displayed higher mortality than those exposed to LF. Furthermore, mysids subjected to continuous exposure of 0.001% LF across three generations exhibited significant inhibition of the feeding rate, more pronounced growth retardation along with an extended intermolt duration, and a diminished rate of reproduction compared to the control. A noteworthy inhibition of the feeding rate and growth was observed in the first generation exposed only to the LF sample. However, although the reproduction rate was not significantly affected. Collectively, these findings underscore the potential harm posed by sublethal concentrations of wastewater to the health of mysid populations under consistent exposure.

Omission of Breast Surgery in Predicted Pathologic Complete Response after Neoadjuvant Systemic Therapy: A Multicenter, Single-Arm, Non-inferiority Trial

PURPOSE

Advances in chemotherapeutic and targeted agents have increased pathologic complete response (pCR) rates after neoadjuvant systemic therapy (NST). Vacuum-assisted biopsy (VAB) has been suggested to accurately evaluate pCR. This study aims to confirm the non-inferiority of the 5-year disease-free survival of patients who omitted breast surgery when predicted to have a pCR based on breast magnetic resonance imaging (MRI) and VAB after NST, compared with patients with a pCR who had undergone breast surgery in previous studies.

METHODS

The Omission of breast surgery for PredicTed pCR patients wIth MRI and vacuum-assisted bIopsy in breaST cancer after neoadjuvant systemic therapy (OPTIMIST) trial is a prospective, multicenter, single-arm, non-inferiority study enrolling in 17 tertiary care hospitals in the Republic of Korea. Eligible patients must have a clip marker placed in the tumor and meet the MRI criteria suggesting complete clinical response (post-NST MRI size ≤ 1 cm and lesion-to-background signal enhancement ratio ≤ 1.6) after NST. Patients will undergo VAB, and breast surgery will be omitted for those with no residual tumor. Axillary surgery can also be omitted if the patient was clinically node-negative before and after NST and met the stringent criteria of MRI size ≤ 0.5 cm. Survival and efficacy outcomes are evaluated over five years.

DISCUSSION

This study seeks to establish evidence for the safe omission of breast surgery in exceptional responders to NST while minimizing patient burden. The trial will address concerns about potential undertreatment due to false-negative results and recurrence as well as improved patient-reported quality of life issues from the omission of surgery. Successful completion of this trial may reshape clinical practice for certain breast cancer subtypes and lead to a safe and less invasive approach for selected patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05505357. Registered on August 17, 2022. Clinical Research Information Service Identifier: KCT0007638. Registered on July 25, 2022.

Chronic exposure to environmental concentrations of harmful algal bloom-forming dinoflagellates induces oxidative stress and reduces immune and hepatic functions in red seabream

Harmful algal blooms (HABs) caused by dinoflagellates can be detrimental to aquaculture and fisheries. However, little is known regarding their ichthyotoxic effects on fish, particularly after chronic exposure to sublethal levels. In this study, significant modulations in physiology, immunity, antioxidant components, and hepatic indicators owing to non-toxin-producing dinoflagellate strains (Alexandrium affine and Cochlodinium polykrikoides) were analyzed in juvenile red seabream, Pagrus major, exposed to sublethal concentrations (0, 1, and 100 cells mL^-1) for 60 days. At 60 days, higher mortality was induced by A. affine than by C. polykrikoides. Significant increases in respiration rate and plasma cortisol were observed in red seabream exposed to 100 cells mL^-1 of the two dinoflagellates. Intracellular reactive oxygen species and malondialdehyde levels were significantly elevated in the gill and liver tissues in response to 100 cells mL^-1 of either dinoflagellate. Immunity parameters such as alternative complement activity, lysozyme activity, and total immunoglobulin content were significantly decreased during exposure to 100 cells mL^-1 of the two dinoflagellates. Although no significant change was observed in the gonadosomatic index, the hepatosomatic index was significantly decreased by exposure to 100 cells mL^-1 of the two dinoflagellates on day 60. The significant decrease in enzymatic activities of ethoxyresorufin-O-deethylase, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase upon exposure to 100 cells mL^-1 of either dinoflagellate suggested impaired hepatic function through prolonged exposure. Our results suggest that consistent exposure to sublethal concentrations of HAB-forming dinoflagellates is detrimental to fish physiology and biochemical defenses.

Chronic effects of environmental concentrations of antifoulant diuron on two marine fish: Assessment of hormone levels, immunity, and antioxidant defense system

The presence and toxicity of waterborne diuron in aquatic environments pose a severe threat to non-target organisms. However, the chronic impact of diuron in marine fish has been poorly investigated. In this study, we report the chronic effects (30 and 60 days) of environmentally relevant concentrations of diuron (0.1, 1, and 10 μg L^-1) on economically important marine fish, red seabream (Pagrus major), and black rockfish (Sebastes schlegelii) by evaluating several parameters, including hormone levels, immunity, hepatic function, and antioxidant defense. Significant decreases in 17β-estradiol and 11-ketotestosterone levels and gonadosomatic index were observed on day 60 in fish exposed to 10 μg L^-1 diuron. Parameters of immunity, such as alternative complement activity, lysozyme activity, and total immunoglobulin levels, were significantly lowered by 60-day exposure to 10 μg L^-1 diuron in both fish. Significant decreases in the hepatic enzyme activities of alanine transaminase and aspartate transaminase were observed with an induction of cortisol on day 60 in fish exposed to 10 μg L-¹ diuron. Intracellular malondialdehyde and glutathione levels were significantly increased by 10 μg L-¹ diuron at day 60 with an increase in the enzymatic activities of catalase and superoxide dismutase. Overall, black rockfish were more sensitive to diuron than red seabream. These results suggest that consistent exposure to environmentally relevant concentrations of diuron is detrimental to the reproduction, immunity, and health of marine fish.

The complete mitochondrial genome of the terebellid polychaete Neoamphitrite affinis (Polychaeta; Terebellidae)

Here, we sequenced and annotated the complete mitochondrial genome for the terebellid polychaete, Neoamphitrite affinis (Malmgren 1866). The complete mitogenome of N. affinis is 15,823 bp, with 33.4% A, 18.2% C, 11.5% G, and 37.0% T. The circular N. affinis mitochondrial genome comprises 13 protein-coding genes (PCGs), 23 transfer RNA (tRNA) genes including 2 methionine tRNA genes, 2 ribosomal RNA (rRNA) genes, and a non-coding region. Phylogenomic analysis based on 26 in-group taxa belonging to the two main clades, Sedentaria and Errantia, is congruent with published phylogenetic relationship for annelids, which N. affinis was grouped with Pista cristata (Terebellida; Terebellidae). This mitogenome resource will be useful for future phylogenetic studies of families belonging to Sedentaria.

Characterization and phylogenetic analysis of the complete mitochondrial genome of the firemouth cichlid, Thorichthys meeki (Perciformes: Cichlidae)

Here, we report information on the complete mitochondrial genome of the firemouth cichlid, Thorichthys meeki (Brind 1918). Illumina HiSeq genome sequencing produced the assembly of a circular mitogenome of 16,527 base pairs (bp) from T. meeki consisting of 46.8% GC nucleotides, 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a putative control region as shown in the typical teleost gene composition. The gene order of the T. meeki mitogenome was identical to that of other cichlid species. A maximum likelihood phylogenetic tree based on mitochondrial PCGs showed a close relationship of T. meeki with Thorichthys aureus (Gunther 1862) within Heroini tribe.

First complete mitochondrial genome from family Moinidae, Moina macrocopa (Straus, 1820) (Cladocera; Moinidae)

We sequenced and annotated the complete mitochondrial genome for the freshwater water flea Moina macrocopa (Straus, 1820). This is the first mitogenome for the family Moinidae. The complete mitogenome of M. macrocopa is 16,072 bp, with 35.8% A, 17.6% C, 12.8% G, and 33.8% T. The mitogenome comprises 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a non-coding region. Phylogenomic analysis based on 28 in-group taxa belonging to the orders Anostraca, Diplostraca, and Notostraca is congruent with published phylogenetic relationship for cladocerans, with M. macrocopa being grouped with members of the Daphniidae. This mitogenome resource will be useful for future phylogenetic studies of water fleas.

Characterization and phylogenetic analysis of the complete mitochondrial genome of the rainbow krib, Pelvicachromis pulcher (Perciformes: Cichlidae)

We report the complete mitochondrial genome information of the rainbow krib, Pelvicachromis pulcher (Boulenger 1901). Illumina HiSeq genome sequencing allowed the assembly of a circular mitogenome of 17,196 base pairs (bp) from P. pulcher consisting of 47% GC nucleotides, 13 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a putative control region in the typical teleost gene composition. The gene order of the P. pulcher mitogenome was identical to that of other cichlid species. A maximum likelihood phylogenetic tree based on mitochondrial PCGs showed a relationship of P. pulcher with a cichlid Tylochromis polylepis (Boulenger 1900), suggesting that more complete mitogenomes are needed to explore mitogenome evolution in West African tribes and riverine cichlids, as this genomic information is the first complete mitogenome in the tribe Chromidotilapiini.

Reductive Transformation of Hexavalent Chromium in Ice Decreases Chromium Toxicity in Aquatic Animals

In this study, the toxicity of hexavalent chromium [Cr(VI)] reduced by citric acid in ice was measured using representative aquatic model invertebrates (i.e., rotifer, water flea, amphipod, and polychaete) and a vertebrate (zebrafish) by analyzing short- and/or long-term endpoints that are frequently applied to each animal. Cr(VI) reduction in the presence of citric acid was markedly enhanced in the ice phase compared to that in an aqueous solution through the freeze concentration effect. The highly concentrated Cr(VI) and citric acid in ice grain boundaries were also confirmed using in situ cryogenic confocal Raman spectroscopy. Overall, exposure to Cr(VI) resulted in higher acute and/or chronic effects on aquatic animals, such as drastic mortality, growth inhibition, and decrease in offspring number, whereas the animals were increasingly tolerant to Cr(VI) that was reduced in the ice phase. Sublethal concentrations of Cr(VI) significantly decreased the antioxidant capacity in the aquatic animals. However, when the same concentrations of Cr(VI) were reduced in ice, these treatments showed no modulation or increase in the antioxidant defense system. Taken together, our results suggest that Cr(VI) reduction into Cr(III) was successfully achieved in ice and that this methodology can decrease the actual toxicity of Cr(VI) in aquatic animals.

Chronic exposure to sublethal concentrations of saxitoxin reduces antioxidant activity and immunity in zebrafish but does not affect reproductive parameters

Saxitoxin produced by dinoflagellates and cyanobacteria can be transferred to humans through intoxicated organisms such as fish, but limited research has addressed the adverse effects of this toxin on aquatic organisms. In this study, we measured the potential effects of a 90-day exposure to saxitoxin (0.1 or 1 µg·L ^- 1) on body weight and length, antioxidant defense system, immunity, sex hormones, and genes involved in associated key metabolic pathways in zebrafish (Danio rerio). Significant impairments in body weight and length were observed in response to 1 µg·L ^- 1 saxitoxin in both male and female zebrafish. A significant increase in the levels of malondialdehyde, together with decreased enzymatic activities of catalase and superoxide dismutase, was observed in fish of both sexes exposed to 1 µg·L ^- 1 saxitoxin, indicating the occurrence of lipid peroxidation and oxidative stress. Immune parameters such as alternative complement activity, lysozyme activity, and immunoglobulin content were also significantly reduced. However, exposure of male and female zebrafish to saxitoxin for 90 days did not significantly affect reproductive parameters such as the gonadosomatic index and plasma concentrations of vitellogenin, estradiol, and 11-keto testosterone. Transcriptional responses showed similar trends to those of the biochemical parameters, as genes involved in the antioxidant defense system and immunity were downregulated, whereas the transcription of genes related to reproductive metabolism showed no significant change upon treatment with 1 µg·L ^- 1 saxitoxin. Our findings indicate that long-term exposure to a sublethal concentration of saxitoxin can inhibit growth through induction of oxidative stress and immunosuppression, while the reproductive parameters of zebrafish are not a main target of this toxin at sublethal concentrations.

Complete mitochondrial genome of the six-line wrasse Pseudocheilinus hexataenia (Labriformes, Labridae)

Here, we report the complete mitogenome information of the six-line wrasse Pseudocheilinus hexataenia (Bleeker, 1857). Genome sequencing using the Illumina HiSeq platform allowed the assembly of a circular mitochondrial genome of 17,111 bp from P. hexataenia, consisting of 54% AT nucleotides, 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a putative control region in the typical Labriformes gene composition. The gene order of the P. hexataenia mitochondrion was identical to that of the Labridae mitogenomes. Phylogenetic reconstruction places P. hexataenia with a close relationship with the mitogenome of the goldsinny wrasse, Ctenolabrus rupestris.

The complete mitochondrial genome of Lamprologus signatus (Perciformes: Cichlidae)

In this study, the complete 16,583 bp mitochondrial genome of Lamprologus signatus (Poll, 1952) was determined from a specimen sourced from Lake Tanganyika. The mitogenome contains 37 genes [13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, and 22 transfer RNA (tRNA) genes] and a putative control region, which consists of 27.1% A, 27.0% T, 29.9% C, and 16.0% G, with a total G + C content of 45.9%. A maximum likelihood phylogenetic tree based on mitochondrial PCGs suggested that L. signatus is clustered with members of the tribes Haplochromini and Tropheini. As this is the first report of the entire mitogenome in the tribe Lamprologini, the complete mitochondrial sequence information of L. sigantus will be useful in determining phylogenetic relationships of Pseudocrenilabrinae tribes.

The dinoflagellate Alexandrium affine acutely induces significant modulations on innate immunity, hepatic function, and antioxidant defense system in the gill and liver tissues of red seabream

Alexandrium affine is a global harmful algal bloom (HAB)-forming dinoflagellate. In this study, the effect of non-toxin-producing A. affine on the gill and liver tissues of red seabream, Pagrus major, was analyzed over 24 h exposure and 2 h depuration phases. After exposure to three concentrations of A. affine (4,000, 6,000, and 7,000 cells mL^-1), survival rates, respiration rates, immunities (lysozyme, total Ig), hepatic biomarkers (alanine aminotransferase, ALT; aspartate aminotransferase, AST; and alkaline phosphatase, ALP), lipid peroxidation (malondialdehyde, MDA), and antioxidant defense systems (glutathione, GSH; catalase, CAT; superoxide dismutase, SOD; glutathione peroxidases, GPx; and glutathione reductase, GR) were analyzed in gill and liver tissues. Dose-dependent decreases in survival and respiration rates were detected in red seabream. A. affine levels of to 6,000 and 7,000 cells mL^-1 induced immunosuppression and hepatic impairment in both tissues, as measured by significant decreases in lysozyme activity, total Ig level, ALT, AST, and ALP content. The levels of GSH, CAT, SOD, GPx, and GR were significantly decreased in the gills and liver in response to 7,000 cells mL^-1 of A. affine at 24 h, and MDA was elevated. However, different response patterns were observed between tissues in response to 4,000 cells mL^-1. Activity of antioxidant defense enzymes was significantly elevated in the liver but decreased in the gills. This suggests that the gills were more vulnerable than the liver. In the case of 6,000 and 7,000 cells mL^-1 treatments, higher susceptibility was also detected at 3 h in the gill compared to the overall responses of each parameter measured in liver. Taken together, direct attachment of A. affine to the gill tissue strongly affects immunity and antioxidant capacity of red seabream even after a short exposure period. These results could be helpful for understanding HAB-mediated effects in marine fish.

The complete mitochondrial genome of the terebellid polychaete Thelepus plagiostoma (Terebellida; Terebellidae)

Here, we report the complete mitogenome information of the terebellid polychaete, Thelepus plagiostoma (Schmarda, 1861). Genome sequencing by Illumina HiSeq platform permitted assembly of a circular mitochondrial genome of 15,628 bp from T. plagiostoma consisting of 67% AT nucleotides, 13 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a non-coding region in the typical annelid gene composition. Gene order of the T. plagiostoma mitochondrion is identical to those of the Terebelliformia mitogenomes. Phylogenetic reconstruction places T. plagiostoma within the monophyletic subclass Sedentaria, a sister to Pista cristata in the suborder Terebelliformia.

Characterization and phylogenetic analysis of the complete mitochondrial genome of the polychaete, Melinna cristata

In this study, we report the complete mitogenome sequence of the polychaete, Melinna cristata (Sars, 1851). The circular M. cristata mitochondrial genome is 15,696 bp in length and has an AT content of 66%. As in other polychaetes, the genome has 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a non-coding region. Gene composition and their order in the M. cristata mitochondrion are identical to the Terebelliformia mitogenomes. A maximum-likelihood gene tree based on the M. cristata mitogenome combined with previously published Sedentaria and Errantia mitogenomes revealed that M. cristata forms a clade with two Terebelliformia species.

Characterization of the complete mitochondrial genome of the scale worm, Eunoe nodosa (Phyllodocida; Polynoidae) from the Beaufort Sea

To increase the mitogenome data available for robust phylogeny, we sequenced the complete mitochondrial DNA of the scale worm Eunoe nodosa (Sars, 1861) in the family Polynoidae of the order Phyllodocida. The complete mitogenome has 15,366 bp and has 28.9% A, 13.2% C, 19.0% G, and 38.8% T. Using MITOS and tRNAscan-SE, we identified the 13 typical protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a non-coding region. Phylogenomic analysis based on 27 in-group taxa belonging to five families of the subclass Errantia show congruence with the published phylogenetic relationship within the Polynoidae, in which E. nodosa lies in the clade of shallow water species.

LEP as a potential biomarker in prognosis of breast cancer: Systemic review and meta analyses (PRISMA)

PURPOSE

Obesity strongly affects the prognosis of various malignancies, including breast cancer. Leptin (LEP) may be associated with obesity and breast cancer prognosis. The purpose of our study was to determine the prognostic value of LEP in breast cancer.

METHOD

We conducted a multi-omic analysis to determine the prognostic role of LEP. Different public bioinformatics platforms (Oncomine, Gene Expression Profiling Interactive Analysis, University of California Santa Cruz Xena, bc-GenExMiner, PrognoScan database, R2-Kaplan-Meier Scanner, UALCAN, Search Tool for the Retrieval of Interacting Genes/Proteins database , and The Database for Annotation, Visualization and Integrated Discovery) were used to evaluate the roles of LEP. Clinicopathological variables were evaluated.

RESULTS

LEP was downregulated in breast cancer tissues compared to levels in normal tissues. By co-expressed gene analysis, a positive correlation between LEP and SLC19A3 was observed. Based on the clinicopathological analysis, low LEP expression was associated with older age, higher stage, lymph node status, human epidermal growth factor receptor 2 (HER2) status, estrogen receptor (ER+) positivity, and progesterone receptor (PR+) positivity. Kaplan-Meier survival analysis showed that low LEP expression indicated a poorer prognosis. LEP is hypermethylated in breast cancer tissues in PrognoScan and R2-Kaplan Meier Scanner, and low LEP expression was correlated with poor prognosis. LEP protein-protein interactions were analyzed using Search Tool for the Retrieval of Interacting Genes/Proteins database. Gene ontology analysis results showed that cellular component is mainly associated with the endosome lumen, cytosol, and secretory granules and is upregulated. For the biological process energy reserve, metabolic processes exhibited the greatest regulation compared to the others. In molecular function, it was mainly enriched in a variety of combinations, but hormone activity showed the highest regulation.

CONCLUSION

Our study provides evidence for the prognostic role of LEP in breast cancer and as a novel potential therapeutic target in such malignancies. Nevertheless, further validation is required.

Complete mitochondrial genome of the marine polychaete, Nereis zonata (Phyllodocida, Nereididae) isolated from the Beaufort Sea

Here, we present the first whole mitogenome sequence of the marine polychaete, Nereis zonata, isolated from the Beaufort Sea. The mitochondrial genome of N. zonata is 15,757 bp in length and consists of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and a non-coding region that is typical of polychaetes. GC content of the N. zonata mitogenome is 37.2%. A maximum-likelihood gene tree based on the N. zonata mitogenome combined with previously published annelid mitogenome data revealed that N. zonata is clustered with Cheilonereis cyclurus, which form a sister group to Nereis sp.

The first complete mitochondrial genome from the family Solasteridae, Crossaster papposus (Echinodermata, Asteroidea)

The common sunstar, Crossaster papposus, belongs to the family Solasteridae whose ordinal classification has been unstable. Here, for the first time, we assembled and annotated the complete mitochondrial genome of the common sunstar, C. papposus Linnaeus, 1767. The circular genome of C. papposus is 16,335 bp in length and contains 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, a control region, and large and small ribosomal subunits. The overall genomic structure and gene arrangement were identical to the reported mitochondrial genomes of sea star species, and a phylogenetic analysis of 13 PCGs recovers a closest relationship with the derived cluster of the paraphyletic order Valvatida.

Temperature elevation stage-specifically increases metal toxicity through bioconcentration and impairment of antioxidant defense systems in juvenile and adult marine mysids

Metals are of serious concern due to their toxicity, persistency, and accumulation potential in aquatic animals. However, limited information is available on the combined effects of metal with temperature elevation, which is one of the future climate changes suggested for the oceans. In this study, the effect of temperature elevation was investigated by analyzing toxicity, bioconcentration, and antioxidant response in juvenile and adult marine mysids upon exposure to 20 °C and 25 °C for 48 h and 96 h. Based on LC₅₀ values, toxicity of metals was highly reliant on temperature, exposure period, and age. Elevation in temperature significantly increased the whole metal toxicity in juveniles. Bioconcentration was elevated by increasing exposure period and metal concentration. Significant elevation of malondialdehyde (MDA) and depletion of glutathione (GSH) was measured in juveniles, while significant elevation of both MDA and GSH was detected in adults. Subsequently, enzymatic activities of antioxidant enzymes in catalase (CAT) and superoxide dismutase (SOD) increased significantly in adults at 48 h and 96 h, whereas most activities were significantly lowered in juveniles at 96 h. These results suggest that the early life stage of marine mysids is more sensitive to the combined effect of metal and temperature than adult stage due to an impairment in the induction of the antioxidant defense system.

Prolonged exposure to hypoxia inhibits the growth of Pacific abalone by modulating innate immunity and oxidative status

In aquatic animals, hypoxia is associated with growth retardation, impaired immunity, susceptibility to pathogens, oxidative stress, and mortality. However, the relative long-term effects of hypoxia on bivalves, including abalone, are not well understood. In this study, we examined the effects of exposure to hypoxic (2.5 and 4 mg O₂ L^-1) and normoxic (8 mg O₂ L^-1) conditions on the growth, survival, and immune and antioxidant responses of the economically important Pacific abalone Haliotis discus hannai over a 4 month period. We observed that exposure to 2.5 mg O₂ L^-1 resulted in marked reductions in assessed shell parameters, average meat weight, and survival compared with exposure to 4 and 8 mg O₂ L^-1. There were also significant reductions in oxygen consumption and ammonia-N excretion in abalone exposed to 2.5 mg O₂ L^-1. We also detected initial immunosuppression in the 2.5 mg O₂ L^-1-treated abalone, as evidenced by a significant reduction in total hemocytes and inhibition of antibacterial and lysozyme activities. Furthermore, intracellular malondialdehyde concentrations were significantly elevated at 1 month in the 2.5 mg O₂ L^-1 treatment group, whereas there were reductions in the levels of glutathione and enzymatic activities of catalase and superoxide dismutase, thereby indicating potential hypoxia-induced oxidative stress and a depression of antioxidant capacity. After 4 months of treatment, severe hypoxia (2.5 mg O₂ L^-1) had significantly modulated all measured parameters, whereas exposure to 4 and 8 mg O₂ L^-1 had induced no significant effects. Collectively, our observations indicate that under long-term exposure to hypoxia, Pacific abalone failed to maintain an effective antioxidant defense system and adequate immunity, with the observed biochemical disruptions leading to a reduction in growth and survival.

Constant and intermittent hypoxia modulates immunity, oxidative status, and blood components of red seabream and increases its susceptibility to the acute toxicity of red tide dinoflagellate

Hypoxia is an increasing threat to aquatic ecosystems and its impact on economically and ecologically important marine fish species needs to be studied. Especially, the consequences of hypoxia when occurring along with harmful algal blooms (HABs) are currently not well documented. In this study, we investigated the effect of constant and intermittent (daily and weekly) hypoxia on respiration, immunity, hematological parameters, and oxidative status of red seabream for 2, 4, and 6 weeks. Under constant and daily intermittent hypoxia, respiration rate significantly increased in 2 weeks compared to the control. Constant and daily intermittent hypoxia caused significant decreases in the activity of alternative complement pathway, lysozyme, and the level of total immunoglobulin (Ig), as well as significant increases in the concentrations of cortisol, hemoglobin, red blood cells, and white blood cells. A significantly higher level of malondialdehyde was measured for all hypoxia-exposed groups, indicating lipid peroxidation and oxidative stress. At 4 and 6 week, the level of glutathione and enzymatic activities of glutathione reductase and glutathione peroxidase were significantly decreased after constant and daily intermittent hypoxia challenge. The enzymatic activities of superoxide dismutase and catalase were significantly increased at 2 and 4 weeks, but they were decreased after 6 weeks by constant and daily intermittent hypoxia. Constant and daily intermittent hypoxia with subsequent non-toxin producing dinoflagellate Cochlodinium polykrikoides treatment significantly reduced the respiration rate in 3 and 24 h exposure and survival rate of red seabream. Taken together, the red seabream can be vulnerable to HABs under hypoxia condition through inhibition of immunity and antioxidant defense ability. Our findings are helpful in better understanding of molecular and physiological effects of hypoxia, which can be used in aquaculture and fisheries management.

Inorganic nitrogen compounds reduce immunity and induce oxidative stress in red seabream

In this study, the effect of ammonia derived from different stocking densities on immunological, hematological, and oxidative stress parameters was analyzed in the blood or liver of red seabream. Density- and time-dependent increases in inorganic nitrogen compounds were measured for 20 days by analyzing the three major inorganic nitrogen compounds, total ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen. Three immunity parameters, alternative complement activity, lysozyme activity, and total immunoglobulin content were significantly decreased in the blood at the highest stocking density (10 kg m^-3). The concentrations of hemoglobin and white blood cells were significantly decreased at 10 kg m^-3, while there was no significant change in red blood cells. The significant increases in cortisol level and the enzymatic activities of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase at 10 kg m^-3 clearly supported inorganic nitrogen compounds-triggered stress. A significant elevation of lipid peroxidation value and depletion of intracellular glutathione were observed at 5 and/or 10 kg m^-3 in the liver tissue. The hepatic enzymatic activities of antioxidant defense enzymes, catalase and superoxide dismutase were also significantly increased. When a protein skimmer removes the inorganic nitrogen compounds at the highest density, most parameters showed no significant change. Taken together, these results suggest that accumulated inorganic nitrogen compounds at the highest stocking density inhibit innate immunity and induce oxidative stress in red seabream. This information will be helpful to maintain homeostasis of red seabream by controlling immunity and oxidative status through inorganic nitrogen compounds removal in intensive culture condition.

Exposure to sublethal concentrations of zinc pyrithione inhibits growth and survival of marine polychaete through induction of oxidative stress and DNA damage

Effects of zinc pyrithione (ZnPT) and inorganic Zn (ZnCl₂) were evaluated on a marine polychaete at sublethal concentrations for 14 days. ZnPT decreased the burrowing activity and AChE activity with higher acute toxicities, implying its cholinergic effect. Both ZnPT and ZnCl₂ increased MDA levels at higher concentrations, suggesting lipid peroxidation and oxidative stress. In the ZnPT-treated polychaete, enzymatic activities of CAT and SOD were elevated with an increase in DNA damage, whereas the levels of GSH, GPx, GR, and GST were decreased. However, in the ZnCl₂-treated polychaete, the level of GSH and enzymatic activities of CAT, SOD, GPx, GR, and GST were significantly elevated to resist cellular damage. During 97 days depuration experiment, significant mortality and growth retardation were observed in the ZnPT-exposed polychaete. Overall, ZnPT was found to be more toxic than ZnCl₂ with the harmful impact on antioxidant defense system and DNA stability in marine polychaete.

Complete mitochondrial genome of the lemon damsel, Pomacentrus moluccensis (Perciformes, Pomacentridae)

Pomacentrus moluccensis Bleeker, 1853 (Pomacentridae) is a bright yellow damselfish. Here, we assembled a complete 16,801 bp genome for P. moluccensis mitochondrion by employing the Illumina MiSeq platform. The complete mitochondrial genome contained 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and one putative control region. The overall genomic structure of P. moluccensis mitochondrion was conserved with the gene arrangements of mitogenomes published in subfamily Pomacentrinae, and phylogenetic analysis confirmed the sister relationship among the genus Amblyglyphidodon, Amphiprion, and Chrysiptera. This complete mitochondrial DNA information of P. moluccensis will provide essential molecular reference to elucidate the geographical distribution, the phylogenetic relationship, and evolutionary history of the damselfish genus Pomacentrus.

Benzo[a]pyrene constrains embryo development via oxidative stress induction and modulates the transcriptional responses of molecular biomarkers in the marine medaka Oryzias javanicus

Embryos from the marine medaka fish Oryzias javanicus were treated with eight concentrations of benzo[a]pyrene (BaP) (0.001, 0.01, 0.1, 1, 2, 5, 10, or 20 μg L^--1) after they had been fertilized. Significant mortality and hatching delays were detected in embryos that had been exposed to 10 and 20 μg L^-1 BaP for 4 weeks. The mortality rate after hatching was higher in the medaka that had been previously exposed to > 2 μg L^-1 BaP. Significant elevations in intracellular reactive oxygen species and malondialdehyde contents were measured and the mRNA expressions of the antioxidant defense system genes (gst, sod, cat, and gpx) increased in the embryos exposed to 10 and 20 μg L^-1 BaP for 1 week. The hsp70, ahr, and cyp1a transcriptional responses were also significantly upregulated in the exposed groups after 1 week. The alterations to the in vivo parameters and molecular components suggested that waterborne BaP had a toxic effect on marine medaka embryos. Finally, fin defects, spinal curvature, and cardiac edema were highly induced when the embryos were exposed to > 5 μg L^-1 BaP.

Complete mitochondrial genome of the marine polychaete Hediste japonica (Phyllodocida, Nereididae)

To date, only five species are registered in the genus Hediste, and complete mitochondrial genome is reported in one species, Hediste diadroma. In this study, a complete 15,783 bp genome for the marine polychaete H. japonica mitochondrion was assembled through Illumina HiSeq platform. The complete mitochondrial genome of H. japonica contained 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and one control region. Overall genomic structure and gene orientation of H. japonica mitogenome are identical to those of H. diadroma. Phylogenetic analysis using the maximum likelihood method validated the sister relationship between Hediste sp. and other polychaetes. This information will be useful to understand geographical distribution, phylogenetic relationship, and evolutionary history of marine polychates.

Complete mitochondrial genome of the crinoid echinoderm, Florometra species (Echinodermata, Crinoidea)

In this study, we report the sequence of the mitochondrial genome (mitogenome) of the crinoid echinoderm, Florometra species (Echinodermata, Crinoidea). The complete mitogenome of Florometra sp. was 15,792 base pairs long and was composed of 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and three regions of unassigned sequence (UAS) including one putative control region. Unique nucleotide composition, a clear positive bias for T with an apparent loss of C in PCGs as observed in the Crinoidea mitogenomes, was also seen in the Florometra sp. mitogenome (45% T, 12% C). Phylogenetic analysis with the concatenated nucleotide sequences of entire PCGs of echinoderms confirmed that Florometra sp. is highly related to F. serratissima within the family Crinoidea.

Waterborne zinc pyrithione modulates immunity, biochemical, and antioxidant parameters in the blood of olive flounder

In this study, potential immunological and hematological effects of different concentrations (0, 1, 10, and 50 μg L^-l) of waterborne zinc pyrithione (ZnPT) were studied in the blood of the olive flounder Paralichthys olivaceus over 30 days. Reduced alternative complement activity (ACH50) and lysozyme activity were measured in fish exposed to 10 and/or 50 μg L^-l of ZnPT for 20 days. Decreased levels of total Ig were also observed in response to 10 and/or 50 μg L^-l ZnPT during the exposure period. Levels of cortisol, a marker of stress, were significantly increased by 10 and 50 μg L^-l ZnPT from day 10, and by 1 μg L^-l exposure on day 30. The levels of red blood cells (RBCs) and white blood cells (WBCs) decreased following exposure to 10 and/or 50 μg L^-l ZnPT, while no significant change was observed in hemoglobin level. Concentrations of total protein and albumin were significantly reduced with 50 μg L^-l ZnPT at day 20. Alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activities were significantly increased following exposure to 10 and/or 50 μg L^-l ZnPT. Lipid peroxidation was induced by ZnPT, and higher concentrations (10 and 50 μg L^-l) significantly increased intracellular malondialdehyde levels during exposure. Regarding the subsequent antioxidant response, intracellular glutathione levels increased significantly in response to 10 and 50 μg L^-l ZnPT on days 20 and 30. Similarly, catalase and superoxide dismutase activity was significantly increased in response to 10 and 50 μg L^-l ZnPT after day 10. Taken together, changes in the studied parameters suggested the immunotoxicity of ZnPT, with modulations observed in hematological homeostasis and oxidative stress induction in the blood of olive flounder.

Effects of sublethal concentrations of the antifouling biocide Sea-Nine on biochemical parameters of the marine polychaete Perinereis aibuhitensis

Sea-Nine™ 211 is an emerging biocide that has an adverse impact on aquatic environments. In this study, the marine polychaete Perinereis aibuhitensis was exposed to Sea-Nine (0.1, 1, and 10 μg L^-1), and acute toxicity and biochemical responses such as changes in the intracellular contents of malondialdehyde (MDA) and glutathione (GSH) and enzymatic activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and acetylcholinesterase (AChE) were evaluated over a period of 14 d. Determined median lethal doses, LC50 were 268 μg L^-1, 142 μg L^-1, and 55 μg L^-1 at 24 h, 96 h, and 14 d, respectively. The MDA content increased significantly in a dose- and time-dependent manner, indicative of lipid peroxidation-related oxidative damage. Significantly higher intracellular GSH levels and antioxidant defense-related enzyme (CAT, SOD, GPx, GR, and GST) activities were observed after exposure to 10 μg L^-1 Sea-Nine. In contrast, Sea-Nine treatment significantly reduced AChE activity at the highest concentration of Sea-Nine used (10 μg L^-1). Taken together, these results indicate that sublethal concentrations of Sea-Nine are toxic to marine polychaetes through potential lipid peroxidation, induction of oxidative stress, and modulation of the cholinergic system. Our results can contribute to biomonitoring of aquatic environments and ecotoxicological research through the measurements of polychaete cellular defenses against waterborne biocides.

Red tide dinoflagellate Cochlodinium polykrikoides induces significant oxidative stress and DNA damage in the gill tissue of the red seabream Pagrus major

The ichthyotoxic Cochlodinium polykrikoides is one of the most harmful bloom-forming dinoflagellates. In the present study, the economically important red seabream Pagrus major was exposed to sublethal concentrations of C. polykrikoides (i.e., 1,000 and 3,000 cells mL^-1) for 24 h, and the antioxidant defense system and DNA damage dose-specific responses were analyzed during the exposure and additional depuration period (2 h) in the gill tissue. No significant ichthyotoxicity was observed under different light and dark conditions, while significantly lower levels of opercular respiratory rate were measured in the C. polykrikoides-exposed red seabream. Intracellular malondialdehyde (MDA) content increased significantly in the 3,000 cells-exposed gill tissues at 24 h and the increased level was maintained during depuration. Intracellular glutathione (GSH) levels were significantly depleted following exposure to 3,000 cells mL^-1 of C. polykrikoides, but the levels increased significantly in the depuration phase. Overall, significantly higher activity of antioxidant defense system enzymes such as catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx) were observed in the 3,000 cells mL^-1-exposed gill tissues at 24 h and during depuration. Analysis of the two reliable DNA damage parameters, Olive tail moment and percent tail DNA, showed significantly elevated levels of DNA damage in the 1,000 and 3,000 cells mL^-1-exposed gill tissue. Increases in the activity of the antioxidant defense system and DNA damage may be one of the major mechanisms mediating C. polykrikoides-induced devastation in aquaculture and fisheries.

Waterborne manganese modulates immunity, biochemical, and antioxidant parameters in the blood of red seabream and black rockfish

Immunotoxic effects of manganese (Mn) were investigated in the blood of the economically important marine fish, red seabream (Pagrus major) and black rockfish (Sebastes schlegelii) when exposed to different concentrations of Mn (0, 0.5, 1, and 2 mg L^-1) for 14 days. During exposure, the levels of alternative complement activity in both fish were significantly lowered at 2 mg L^-1 of Mn of exposure. Lysozyme activity was significantly decreased in black rockfish in all concentrations of Mn after 14 days, while in red seabream, the decrease was significant with concentrations of 1 and 2 mg L^-1 of Mn after 7 and 14 days of exposure. A significantly low level was observed only in the 2 mg L^-1-exposed red seabream on day 14 of exposure. The concentrations of hemoglobin, red blood cells, white blood cells, and total serum proteins were significantly decreased in both fish under exposure to 1 and 2 mg L^-1 of Mn, while cortisol, alanine transferase, aspartate transaminase, and alkaline phosphatase levels were significantly increased compared to the levels of control groups. No significant change was found in serum glucose and albumin except in red seabream exposed to 2 mg L^-1 of Mn for 14 days. The responses of the antioxidant defense system were significantly induced in both fish after exposure to 1 and 2 mg L^-1 of Mn on day 7 and 14 of exposure. Taken together, alterations of these parameters suggest the immunotoxicity of waterborne Mn produced by the modulation of hematological components and the induction of oxidative stress in the blood of these marine fish.

Chlorothalonil induces oxidative stress and reduces enzymatic activities of Na+/K+-ATPase and acetylcholinesterase in gill tissues of marine bivalves

Chlorothalonil is a thiol-reactive antifoulant that disperses widely and has been found in the marine environment. However, there is limited information on the deleterious effects of chlorothalonil in marine mollusks. In this study, we evaluated the effects of chlorothalonil on the gill tissues of the Pacific oyster, Crassostrea gigas and the blue mussel, Mytilus edulis after exposure to different concentrations of chlorothalonil (0.1, 1, and 10 μg L⁻¹) for 96 h. Following exposure to 1 and/or 10 μg L⁻¹ of chlorothalonil, malondialdehyde (MDA) levels significantly increased in the gill tissues of C. gigas and M. edulis compared to that in the control group at 96 h. Similarly, glutathione (GSH) levels were significantly affected in both bivalves after chlorothalonil exposure. The chlorothalonil treatment caused a significant time- and concentration-dependent increase in the activity of enzymes, such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR), in the antioxidant defense system. Furthermore, 10 μg L⁻¹ of chlorothalonil resulted in significant inhibitions in the enzymatic activity of Na⁺/K⁺-ATPase and acetylcholinesterase (AChE). These results suggest that chlorothalonil induces potential oxidative stress and changes in osmoregulation and the cholinergic system in bivalve gill tissues. This information will be a useful reference for the potential toxicity of chlorothalonil in marine bivalves.

Long-term exposure to waterborne nonylphenol alters reproductive physiological parameters in economically important marine fish

Low concentrations of nonylphenol (NP) in aquatic environment can induce drastic effects on the endocrine system in animals. In this study, we examined the modulatory effects of NP on reproductive and physiological parameters in juveniles of the red seabream and black rockfish following waterborne NP exposure (0, 1, 10, and 50 μg L^-1) for 60 days. In red seabream exposed to 50 μg L^-1 NP, plasma levels of 17β-estradiol (E2) and 11-ketotestosterone (11-KT) were significantly lower at 30 and 60 days, while E2 levels were slightly higher in 10 μg L^-1-exposed individuals at day 30. Similarly, significantly lower levels of E2 and 11-KT were observed in 10 and 50 μg L^-1-exposed black rockfish at 60 days, whereas the E2 level was higher in 1 μg L^-1-exposed individuals at day 30. After exposure to NP, plasma and mRNA levels of vitellogenin (VTG) were significantly higher in both species at 30 and 60 days, similar to the inducible effects from synthetic estrogen. Plasma cortisol levels were significantly elevated by relatively higher concentrations of NP (10 and 50 μg L^-1) at 30 and 60 days. Finally, 60 days of exposure of 50 μg L^-1 NP significantly decreased the gonadosomatic index (GSI) and increased the hepatosomatic index (HSI) in both species. The results obtained from this study provide an evidence of the endocrine disrupting potential of waterborne NP on early stages of economically important marine fish. The NP-triggered endocrine modulation can induce effects on the development of reproductive and metabolic organs in fish species.

Dose- and age-specific antioxidant responses of the mysid crustacean Neomysis awatschensis to metal exposure

Waterborne metals can adversely affect an organism's innate defenses through oxidative stress. In the present study, the marine mysid Neomysis awatchensis was exposed to sublethal concentrations (1/10 and 1/5 of the median LC50s) of As, Cd, Cu, Pb, and Zn for 48 or 96 h at the juvenile and adult developmental stages, and the dose- and age-specific antioxidant defense system responses were characterized. Metal accumulation and modulation of four key antioxidant biomarkers, malondialdehyde (MDA), glutathione (GSH), superoxide dismutase, and catalase, were measured in juvenile and adult mysids. Based on LC50, level of metal toxicity was dependent on metal concentration, developmental stage, and the exposure duration. Intracellular MDA content was increased in the As-, Cu-, Pb-, and Zn-exposed juvenile mysids after exposure for 48 and/or 96 h, while increases in MDA content were observed in adult mysids following Cu and Zn exposure. Interestingly, GSH content was differentially modulated, where intracellular GSH levels decreased in juvenile mysids following Cd, Cu, Pb, and Zn exposure, but significantly increased in metal-exposed adult mysids, except for Pb exposure. The catalase and superoxide dismutase activities displayed similar stage-specific increases or decreases as also observed for the different GSH levels, suggesting that the susceptibility to and defense against metal-induced oxidative stress differed based on stage. Modulations in MDA and GSH content and enzymatic activity of the antioxidant defense system indicate that mysid antioxidant defense system factors are intimately connected during control of oxidative imbalances with different capacities at different developmental stages.