Lihui An

Trophodynamics of polybrominated diphenyl ethers and methoxylated polybrominated diphenyl ethers in a marine food web

The current study measured the concentrations of 14 polybrominated diphenyl ethers (PBDEs) and eight methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in a marine food web and estimated their trophic magnification factors (TMFs), to highlight the differences between invertebrates, fish, and seabirds. Concentrations of PBDEs were orders of magnitude greater in seabirds (184.07 ± 161.63 ng/g lipid wt) compared with invertebrates and fish (19.01 ± 14.14 ng/g lipid wt). Although the congener profiles in invertebrates, fish, and juvenile seabirds were dominated by BDE-47, the contributions of BDE-99 and BDE-153 in adult seabirds were also significant. Unlike PBDEs, however, higher average MeO-PBDE concentrations were detected in fish (126.27 ± 189.27 ng/g lipid wt) and bivalves (15.96 ± 11.82 ng/g lipid wt) than in seabirds (2.61 ± 2.87 ng/g lipid wt). Correlations between lipid-normalized PBDE concentrations and trophic levels confirmed that seven PBDE congeners were magnified in the invertebrate-fish-seabird food web and that PBDE concentrations increased at a much greater rate across trophic levels in seabirds than in invertebrates and fish. This result indicates that estimating TMFs of PBDEs separately for seabirds, invertebrates, and fish is preferable. For MeO-PBDEs, no significant relationships were obtained in the invertebrate-fish-seabird food web.

Induction of vitellogenin mRNA in juvenile chinese sturgeon (acipenser sinensis gray) treated with 17β-estradiol and 4-nonylphenol

It has been demonstrated that 4-nonylphenol (4-NP) exerts estrogenic effects in diverse fishes. The present study investigated the effects of 4-NP on Chinese sturgeon (Acipenser sinensis Gray) vitellogenin (VTG) gene expression. By reverse transcription-polymerase chain reaction (RT-PCR) using degenerate primers, a 462-base pair fragment of Chinese sturgeon VTG, corresponding to a 154-amino acid sequence, was amplified and sequenced. This sequence exhibited 152/154 identity to the amino acid sequence of white sturgeon (A. transmontano) VTG. Conventional RT-PCR and quantitative real-time RT-PCR were established and used to study the VTG and beta-actin gene expression in the liver of juvenile Chinese sturgeon injected three times with 17beta-estradiol (5 mg/kg body wt/week) or 4-NP (10 or 100 mg/kg/week) in the course of three weeks. Significant induction of VTG gene expression was detected in all treated groups, and no VTG mRNA was detected in the control group. The ratio of VTG to beta-actin analyzed from the results of quantitative real-time RT-PCR reached 0.041 +/- 0.024 (mean +/- SD) in the group receiving 10 mg/kg/week of 4-NP and 4.51 +/- 1.68 in the group receiving 100 mg/kg/week of 4-NP. Chemical analysis of 4-NP showed that the concentrations of 4-NP in the 10 mg/kg/week group and the 100 mg/kg/week group were 2.78 +/- 2.41 and 31.38 +/- 0.26 mcirog/ g wet weight, respectively. Compared with the 4-NP concentrations (0.8-1.92 microg/g wet wt) in fish from the Yangtze River, China, a potential hazard exists regarding 4-NP in Chinese sturgeon. These results represent the first indication of the risk of endocrine-disrupting chemicals for Chinese sturgeon.

CYP1A mRNA expression in redeye mullets (Liza haematocheila) from Bohai Bay, China

Induction of cytochrome P4501A (CYP1A) has been used as a biomarker in fish for monitoring aromatic and organic contaminants. In this study, a partial of CYP1A gene in redeye mullet (Liza haematocheila) was isolated and sequenced, and then a real-time quantitative reverse-transcription polymerase chain reaction assay was developed for quantification of CYP1A mRNA normalized to β-actin. The developed method was applied to detect CYP1A mRNA expression in redeye mullets collected from Nandaihe (reference site) and Dashentang (impacted site) in Bohai Bay, China. CYP1A mRNA expression values were significantly elevated in redeye mullets from Dashentang compared to a reference site--Nandaihe, which was correlated with the contents of different environmentally relevant pollutants in tissues, particularly with PCBs and PBDEs.

Use of heat shock protein mRNA expressions as biomarkers in wild crucian carp for monitoring water quality.

In organisms, the production of heat shock proteins (HSPs) can be induced after exposure to various stressors. In the present study, partial cDNA sequences encoding of HSP30, HSP60, HSP70, and HSP90 genes were isolated and sequenced in the crucian carp (Carassius carassius). Next, quantitative real-time reverse transcription PCR (qRT-PCR) assays normalized to beta-actin were developed to quantify HSP mRNA expression. The same methods were used to detect HSP mRNA expression in the wild crucian carp that were collected from the Hun River. In fish located downstream of the river, we found that the levels of HSP70 and HSP30 in the liver and kidney were higher than fish located upstream, and these differences coincided with changes of the water quality. These results suggest that kidney HSP30 and liver HSP70 expression can serve as sensitive biomarkers for the presence of field environmental stressors in wild crucian carp.

Biomarker responses and genotoxicity in the mud snail (Bullacta exarata) as indicators of coastal contamination.

In the present study different biomarker responses and genotoxicity were determined in wild mud snails (Bullacta exarata) collected from 3 sampling sites in Bohai Bay in northeastern China, which is a region that is under considerable anthropogenic influence. Significant spatial variability of superoxide dismutase (SOD) and metallothionein (MT)-like proteins were recorded, while glutathione transferase (GST), catalase (CAT), and vitellin-like proteins (Vns) were not observed. Furthermore, genomic DNA that was amplified with 4 fluorescence-labeled primer pairs showed variable genetic distances among the 3 wild mud snail populations found in Bohai Bay, which may be correlated with differences in the types of environmental genotoxicants, such as heavy metals and polycyclic aromatic hydrocarbons. This multi-biomarker approach provided an improved understanding of the potential toxicological impact of contaminated sediments on benthic organisms.

Phenolic endocrine-disrupting chemicals and intersex in wild crucian carp from Hun River, China

This study investigated the concentrations of phenolic endocrine-disrupting chemicals (EDCs) and the incidence of ovo-testis (intersex) in wild crucian carp (Carassius carassius) sampled from the Hun River. As expected, nonylphenols (NP) and bisphenol A (BPA) were detected in all samples, and octylphenols (OP) were found in most samples. NP concentrations ranged from 1290 ± 584 to 3111 ± 2071 ng g(-1) wet weight (ww) in July and from 1132 ± 644 to 1556 ± 587 ng g(-1) ww in November; OP ranged from 6 ± 7 to 46 ± 38 ng g(-1) ww in July and from no detection to 22 ± 16 ng g(-1) ww in November; and BPA ranged from 4 ± 9 to 41 ± 24 ng g(-1) ww in July and from 6 ± 5 to 59 ± 24 ng g(-1) ww in November. Moreover, the concentrations of these compounds were higher in fish found down-stream of the sewage treatment plant (STP), and the lowest concentrations were found in fish up-stream of the STP. Concentrations of these EDCs in muscles might be correlated with the prevalence of intersex traits in wild fish, suggesting that these compounds contribute, at least in part, to the occurrence of intersex morphology. Thus, phenolic EDCs discharged from the STP pose a risk to the aquatic ecosystem in the Hun River.

Evidence for the presence of sex steroid hormones in Zhikong scallop, Chlamys farreri

To obtain evidence of the presence of sex steroid hormones in mollusks, hormone variation in the gonads of the Zhikong scallop Chlamys farreri was analyzed using UPLC-MS/MS. These were found, as expected, with concentrations of estrone (E1), 17beta-estradiol (E2), and testosterone (T) in the testes ranging from not detected (ND) to 0.07 ± 0.10, ND to 3.10 ± 2.00, and ND to 2.67 ± 1.55 ng/g wet weight, respectively. In the ovaries, these hormones ranged from ND to 2.45 ± 1.22, ND to 27.90 ± 4.23, and ND to 2.38 ± 1.56 ng/g ww, respectively. The levels of T in males and E2 in females followed a trend similar to the gonadal-somatic index over the course of the reproductive period. In addition, the gene expression of vitellogenin and calmodulin-2 showed similar patterns to T and E2, while the estrogen receptors and calmodulin-1 did not. These results indicate that sex steroids are present in the scallop and that they may regulate endocrine functions during the reproductive process.

Evaluation of estrogenicity of sewage effluent and reclaimed water using vitellogenin as a biomarker

To evaluate the quality of reclaimed water, the estrogenicity of effluent from a sewage treatment plant and of reclaimed water treated with coagulation-sedimentation-filtration using the effluent as raw water was assessed using vitellogenin (VTG) as a biomarker. After a three-week exposure, significant (p < 0.05) induction of VTG occurred in female crucian carp (Carassius carassius) exposed continuously to the secondary effluent and reclaimed water with different dilutions (12.5, 25, 50, and 100% for secondary effluent; 50 and 100% for reclaimed water); no induction of VTG was detected when exposed to 12.5 and 25% reclaimed water. For male fish, however, only 100% secondary effluent induced the production of VTG (mean +/- standard deviation, 38.6 +/- 9.8 microg/ml). When the exposure time was prolonged to three months, VTG was induced significantly in both females and males at all gradient concentrations of secondary effluent and at 50 and 100% reclaimed water. The results indicated that no obvious VTG was detected in fish exposed to reclaimed water diluted more than fourfold. Ozonation of the secondary effluent under an ozone consumption dose of 8.5 mg/L resulted in a VTG level equal to that of 12.5% secondary effluent or 50% reclaimed water. Furthermore, VTG induction reflects the cumulative effects of estrogenic activity in the secondary effluent and reclaimed water compared with the in vitro assays, in which estrogenic activities in effluent changed markedly during the experiment.

Microplastics releasing from personal care and cosmetic products in China

Microplastics (MPs) have become a major global issue; their release from various products affects the aquatic environment, especially marine ecosystems. As a primary source of MPs, personal care and cosmetics products (PCCPs) containing MPs contribute to this environmental risk. We visited several supermarket chains in Beijing, China to identify PCCPs containing MPs. Overall, 7.1% of facial cleansers contained MPs, with an average weight of 25.04±10.69mgMP/g and average size of 313±130μm; whereas, 2.2% of shower gel products contained an average weight of 17.80±7.50mgMPs/g with an average size of 422±185μm. The majority of MPs were made of polyethylene, based on Raman and Fourier transform-infrared spectra analyses, while only a few were made of walnut shells and carbon particles. Finally, estimated 39tons MPs were released into the environment based on PCCPs use in China based on available data.

Ribosomal protein L7 as a suitable reference gene for quantifying gene expression in gastropod Bellamya aeruginosa

Expression levels of eight candidate reference genes were quantified in tissues of gastropod Bellamya aeruginosa exposed for 10 d to various stressors, including fasting, 17β-estradiol, 17α-methyltestosterone, and Cd(2+). The results showed that 18s rRNA was the most highly expressed of the candidate reference genes, while H2A was the least expressed. There were no significant changes (p>0.05) in the expression of the eight genes in tissues among the different treatments. Using RefFinder to evaluate the expression stabilities of the eight candidate reference genes, ribosomal protein was shown to be the most stable reference gene, and no effects were observed among the different stressor treatments. These results indicate that RPL 7 is the most suitable reference gene for quantifying gene expression in B. aeruginosa under environmental stress, which was verified in B. aeruginosa exposed to high doses of E2 for 24 and 72h.