Hypoxia in aquatic invertebrates: Occurrence and phenotypic and molecular responses.

Global deoxygenation in aquatic systems is an increasing environmental problem, and substantial oxygen loss has been reported. Aquatic animals have been continuously exposed to hypoxic environments, so-called "dead zones," in which severe die-offs among organisms are driven by low-oxygen events. Multiple studies of hypoxia exposure have focused on in vivo endpoints, metabolism, oxidative stress, and immune responses in aquatic invertebrates such as molluscs, crustaceans, echinoderms, and cnidarians.

Physiological effects and molecular response in the marine rotifer Brachionus plicatilis after combined exposure to nanoplastics and copper.

Because nanoplastics (NPs) can transport pollutants, the absorption of surrounding pollutants into NPs and their effects are important environmental issues. This study shows a combined effect of high concentrations of NPs and copper (Cu) in the marine rotifer Brachionus plicatilis. Co-exposure decreased the growth rate, reproduction, and lifespan.

Comparative genome analysis of the monogonont marine rotifer Brachionus manjavacas Australian strain: Potential application for ecotoxicology and environmental genomics.

This is the first study to analyze the whole-genome sequence of B. manjavacas Australian (Aus.) strain through combination of Oxford Nanopore long-read seq, resulting in a total length of 108.

The genome of the freshwater monogonont rotifer Brachionus rubens: Identification of phase I, II, and III detoxification genes.

Monogonont rotifers are common species in aquatic environments and make model species for ecotoxicology studies. Whole genomes of several species of the genus Brachionus have been assembled, but no information on the freshwater rotifer Brachionus rubens has been reported. In this study, the whole-genome sequence of B.

Complete mitochondrial genomes of two marine monogonont rotifer strains.

The complete mitochondrial genomes of German strain were 10,721 bp (mitochondrial DNA I) and 12,274 bp (mitochondrial DNA II) in size, while the complete mitochondrial genomes of Australian strain were 10,889 bp (mitochondrial DNA I) and 12,443 bp (mitochondrial DNA II) in size. Of 12 protein-coding genes (PCGs), 99.6% of amino acid sequences were identical between the two strains.

The genome of the freshwater monogonont rotifer Brachionus angularis: Identification of phase I, II, and III detoxification genes and their roles in molecular ecotoxicology.

Brachionus spp. rotifers, which are widely distributed in aquatic environments, have been proposed as model organisms for ecotoxicological studies. Although the genomes of several rotifers belonging to the genus Brachionus have been assembled, the genome for the freshwater rotifer Brachionus angularis remains unknown.

Arsenic exposure combined with nano- or microplastic induces different effects in the marine rotifer Brachionus plicatilis.

Besides the adverse biological effects induced by microplastics (MPs), the effects associated with sorption of ambient pollutants on MPs are considered as an emerging environmental problem as MPs act as a mediator of pollutants. The present study examines the combined effects of nano(micro)plastics (NMPs) and arsenic (As) by exposing the marine rotifer Brachionus plicatilis to MP particles at the micro-scale (6 μm) and nano-scale (nanoplastics, NPs) (50 nm) along with As. In vivo toxicity, bioaccumulation, and biochemical reactions were used to examine the effects of combined exposure.

The genome of the marine monogonont rotifer Brachionus rotundiformis and insight into species-specific detoxification components in Brachionus spp.

The monogonont rotifer Brachionus spp. have been widely used for ecotoxicological studies because of their advantages as one of the most suitable laboratory experimental species. In the present study, we obtained and assembled the whole genome sequence of the rotifer Brachionus rotundiformis, consisting of 13,612 annotated genes with 213 scaffolds and 58 Mb in total length.

The reference genome of the selfing fish Kryptolebias hermaphroditus: Identification of phases I and II detoxification genes.

The selfing fish Kryptolebias hermaphroditus has unique reproductive system for self-fertilization, making genetically homozygous offsprings. Here, we report on high density genetic map-based genome assembly for the K. hermaphroditus Panama line (PanRS).

The genome of the Java medaka (Oryzias javanicus): Potential for its use in marine molecular ecotoxicology.

The Java medaka (Oryzias javanicus) is distributed in tropical brackish water and is considered as an ecotoxicological experimental organism for assessing diverse pollutions and global climate change effects in the ocean. In this study, we sequenced and assembled the genome of O. javanicus using the Oxford Nanopore technique and anchored the scaffolds to the 24 genetic linkage map of a sister species Oryzias melastigma.

Effects of methylparaben, ethylparaben, and propylparaben on life parameters and sex ratio in the marine copepod Tigriopus japonicus.

Parabens are used as a preservative substance in a wide range of man-made products causing deleterious effects on aquatic organisms and therefore, the concern of their effects to aquatic organisms has been increased. In this study, acute toxicity of methylparaben (MeP), ethylparaben (EtP), and propylparaben (PrP) was assessed in the marine copepod Tigriopus japonicus. The acute toxicity assessment resulted in the median lethal concentration (LC50) values of MeP, EtP, and PrP were 29,754, 11,659, and 113 μg/L, respectively, for male and 38,183, 15,371, and 357 μg/L, respectively, for female, indicating the strongest toxicity of PrP, compared to MeP and EtP and the higher sensitivity of males compared to females.

Toxic effects of lead exposure on bioaccumulation, oxidative stress, neurotoxicity, and immune responses in fish: A review.

Lead (Pb) is a highly toxic metal in aquatic environments. Fish are at the top of the food chain in most aquatic environments, and are the most susceptible to the toxic effects of Pb exposure. In addition, fish are one of the most abundant vertebrates, and they can directly affect humans through food intake; therefore, fish can be used to assess the extent of environmental pollution in an aquatic environment.

Adverse effects, expression of defense-related genes, and oxidative stress-induced MAPK pathway in the benzo[α]pyrene-exposed rotifer Brachionus rotundiformis.

To examine the adverse effects of the benzo[α]pyrene (B[α]P), the monogonont rotifer Brachionus rotundiformis was exposed to various concentration of B[α]P (0 [control], 1, 10, and 100 μg/L) and measured life cycle parameters (e.g., mortality, fecundity [cumulated number of offspring], and lifespan), reactive oxygen species (ROS), antioxidant enzymatic activity of glutathione S-transferase (GST).

Genome-wide identification and expression of the entire 52 glutathione S-transferase (GST) subfamily genes in the Cu-exposed marine copepods Tigriopus japonicus and Paracyclopina nana.

In this study, the entire glutathione S-transferases (GSTs), the major phase II detoxification enzyme, were identified in two marine copepod species Tigriopus japonicus and Paracyclopina nana. The genome-wide identification of GSTs in T. japonicus and P.

Genome-wide identification of the entire 90 glutathione S-transferase (GST) subfamily genes in four rotifer Brachionus species and transcriptional modulation in response to endocrine disrupting chemicals.

Genome-wide identification of glutathione S-transferase (GST), a major phase II detoxification enzyme, was investigated in four different aquatic model rotifer species Brachionus koreanus, B. plicatilis, B. rotundiformis, and B.

Adverse effects of the insecticides chlordecone and fipronil on population growth and expression of the entire cytochrome P450 (CYP) genes in the freshwater rotifer Brachionus calyciflorus and the marine rotifer Brachionus plicatilis.

Chlordecone and fipronil are used as an insecticide and have been widely detected in the aquatic environments. However, their toxicity is still poorly investigated in aquatic invertebrates. In this study, we examined effects of chlordecone and fipronil on population growth and transcriptional regulation of the entire cytochrome P450 (CYP) genes in the freshwater rotifer Brachionus calyciflorus and the marine rotifer B.

Effects of bisphenol A and its analogs bisphenol F and S on life parameters, antioxidant system, and response of defensome in the marine rotifer Brachionus koreanus.

To understand the adverse outcome in response to bisphenol A and its analogs bisphenol F and S (BPA, BPF, and BPS), we examined acute toxicity, life parameter, and defensome in the marine rotifer Brachionus koreanus. Among the bisphenol analogs, BPA showed the highest acute toxicity and then BPF and BPS, accordingly in the view of descending magnitude of toxicity. In life parameters including life span and reproduction, BPA, BPF, and BPS were found to cause adverse effect.

Effects of water accommodated fractions (WAFs) of crude oil in two congeneric copepods Tigriopus sp.

Oil pollution has deleterious effects on marine ecosystems. However, the toxicity of crude oil towards Antarctic marine organisms has not been well studied. We compared the deleterious effects of water accommodated fractions (WAFs) of crude oil on reproduction, intracellular reactive oxygen species (ROS) levels, and antioxidant enzymatic activity in Antarctic (Tigriopus kingsejongensis) and temperate (Tigriopus japonicus) copepods.

Nine co-localized cytochrome P450 genes of the CYP2N, CYP2AD, and CYP2P gene families in the mangrove killifish Kryptolebias marmoratus genome: Identification and expression in response to B[α]P, BPA, OP, and NP.

The CYP2 genes are the largest and most diverse cytochrome P450 (CYP) subfamily in vertebrates. We have identified nine co-localized CYP2 genes (∼55kb) in a new cluster in the genome of the highly resilient ecotoxicological fish model Kryptolebias marmoratus. Molecular characterization, temporal and tissue-specific expression pattern, and response to xenobiotics of these genes were examined.

Microplastic Size-Dependent Toxicity, Oxidative Stress Induction, and p-JNK and p-p38 Activation in the Monogonont Rotifer (Brachionus koreanus).

In this study, we evaluated accumulation and adverse effects of ingestion of microplastics in the monogonont rotifer (Brachionus koreanus). The dependence of microplastic toxicity on particle size was investigated by measuring several in vivo end points and studying the ingestion and egestion using 0.05-, 0.

BDE-47 causes developmental retardation with down-regulated expression profiles of ecdysteroid signaling pathway-involved nuclear receptor (NR) genes in the copepod Tigriopus japonicus.

2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) is a persistent organic pollutant (POP) in marine environments. Despite its adverse effects (e.g.