Di-(2-ethylhexyl) phthalate (DEHP) has the potential to disrupt the thyroid endocrine system, but the underlying mechanism is unknown. In this study, zebrafish (Danio rerio) embryos were exposed to ...different concentrations of DEHP (0, 40, 100, 200, 400 μg/L) from 2 to 168 hours post fertilization (hpf). Thyroid hormones (THs) levels and transcriptional profiling of key genes related to hypothalamus-pituitary-thyroid (HPT) axis were examined. The result of whole-body thyroxine (T4) and triiodothyronine (T3) indicated that the thyroid hormone homeostasis was disrupted by DEHP in the zebrafish larvae. After exposure to DEHP, the mRNA expressions of thyroid stimulating hormone (tshβ) and corticotrophin releasing hormone (crh) genes were increased in a concentration dependent manner, respectively. The expression level of genes involved in thyroid development (nkx2.1 and pax8) and thyroid synthesis (sodium/iodide symporter, nis, thyroglobulin, tg) were also measured. The transcripts of nkx2.1 and tg were significantly increased after DEHP exposure, while those of nis and pax8 had no significant change. Down-regulation of uridinediphosphate-glucuronosyl-transferase (ugt1ab) and up-regulation of thyronine deiodinase (dio2) might change the THs levels. In addition, the transcript of transthyretin (ttr) was up-regulated, while the mRNA levels of thyroid hormone receptors (trα and trβ) remained unchanged. All the results demonstrated that exposure to DEHP altered the whole-body thyroid hormones in the zebrafish larvae and changed the expression profiling of key genes related to HPT axis, proving that DEHP induced the thyroid endocrine toxicity and potentially affected the synthesis, regulation and action of thyroid hormones.
Little research on perfluorinated compounds (PFCs) has been conducted in rural areas, although rural PFC sources are less complicated than in urban and industrial areas. To determine the levels and ...geographical distribution of 17 PFC compounds, samples of soil, surface water, and groundwater were collected from eight rural areas in eastern China. The total PFC concentrations (∑PFCs) in soils ranged from 0.34 to 65.8 ng/g ∑PFCs in surface waters ranged from 7.0 to 489 ng/L and ∑PFCs in groundwater ranged from 5.3 to 615 ng/L. Ratios of perfluorononanoic acid/perfluorooctanoic acid (PFNA/PFOA), perfluoro-n-butyric acid/perfluorooctanoic acid (PFBA/PFOA), and perfluoroheptanoic acid/perfluorooctanoic acid (PFHpA/PFOA) in rainwater increased due to the fluorine chemical plants in the surrounding rural and urban areas, suggesting that atmospheric precipitation may carry PFCs and their precursors from the fluorochemical industrial area to the adjacent rural areas.
•PFCs were widely detected, although at low levels, in soil from rural areas in eastern China.•PFC levels in the surface waters were generally higher in the sections south of the Yangtze River.•Atmospheric precipitation may carry PFCs from the fluorochemical industrial area to the adjacent rural areas.
Soil, surface water, and groundwater from rural areas in eastern China were analyzed for perfluorinated compounds (PFCs) and sources of PFCs were discussed.
The presence of chromium (Cr) in cultivated fields affects carbohydrate metabolism of rice (Oryza sativa L.) and weakens its productivity. Little is known about the molecular mechanism of sucrose ...metabolism underlying Cr stress response in rice plants. In the present study, the transcriptome map of sucrose metabolism in rice seedlings exposed to both trivalent and hexavalent chromium was investigated using Agilent 4 × 44K rice microarray analysis. Results indicated that Cr exposure (3 days) significantly (p < 0.05) improved sucrose accumulation, and altered the activities of sucrose synthetase, sucrose phosphate phosphatase, and amylosynthease in rice tissues. We identified 119 differentially regulated genes involved in 17 sucrose metabolizing enzymes and found that gene responses in roots were significantly (p < 0.05) stronger than in shoots under both Cr(III) and Cr(VI) treatment. The network maps of gene regulation responsible for sucrose metabolism in rice plants provide a theoretical basis for further cultivating Cr-resistant rice cultivars through molecular genetic improvement.
Graphene oxide (GO) has widespread concerns in the fields of biological sciences and medical applications. Currently, studies have reported that excessive GO exposure can cause cellular DNA damage ...through reactive oxygen species (ROS) generation. However, DNA damage mediated response of the base excision repair (BER) pathway due to GO exposure is not elucidated yet. Therefore, we exposed HEK293T cells and zebrafish embryos to different concentrations of GO for 24 h, and transcriptional profiles of BER pathway genes, DNA damage, and cell viability were analyzed both in vitro and in vivo. Moreover, the deformation of HEK293T cells before and after GO exposure was also investigated using atomic force microscopy (AFM) to identify the physical changes occurred in the cells' structure. CCK-8 and Comet assay revealed the significant decrease in cell viability and increase in DNA damage in HEK293T cells at higher GO doses (25 and 50 μg/mL). Among the investigated genetic markers in HEK293T cells, BER pathway genes (APEX1, OGG1, CREB1, UNG) were significantly up-regulated upon exposure to higher GO dose (50 μg/mL), however, low exposure concentration (5, 25 μg/mL) failed to induce significant genetic induction except for CREB1 at 25 μg/mL. Additionally, the viscosity of HEK293T cells decreased upon GO exposure. In zebrafish, the results of up-regulated gene expressions (apex1, ogg1, polb, creb1) were consistent with those in the HEK293T cells. Taken all together, the exposure to elevated GO concentration could cause DNA damage to HEK293T cells and zebrafish embryos; BER pathway could be proposed as the possible inner response mechanism.
•GO as a potential emerging pollutant is first investigated using atomic force microscopy (AFM).•GO exposure is first confirmed to cause DNA damage when the concentration is higher than 25 μg/mL in HEK293T cells.•BER pathway could be a possible inner response mechanism for GO exposure both in vitro and in vivo.
Biocomposites of poly(vinyl alcohol) (PVA) incorporated with eggshell powder (ESP) were prepared by solution blending and casting into films. The effects of ESP content (0–50 wt% of dry PVA basis) on ...structure and properties of the resultant PVA/ESP composite films were systematically evaluated. Fourier transform infrared spectroscopy and scanning electron microscopy suggested a strong adhesion and the well-dispersion of ESP particles in the PVA matrix due to the hydrogen-bonding interactions. The incorporation of opaque, hydrophobic and stable ESP in the composite films could consequently decreased their transparency and hydrophilicity while improving their thermal stability. Optimal ESP content in the composite films was found to be 30 wt% in terms of their mechanical and water vapor barrier properties, showing a tensile strength of 38.78 MPa, elongation at break of 165.9%, and water vapor permeability of 1.229 × 10
–12
g cm/cm
2
s Pa, respectively. However, overloading of ESP in the composite films might produce some aggregations and thus have negative effects on their performance. These results indicated that ESP was an excellent biological filler for PVA to prepare composite films with improved properties, which might hold the potential as biodegradable materials for packaging applications.
Di-(2-ethylhexyl) phthalate (DEHP) possesses the potential to interfere with the male reproductive endocrine system in mammals; however, its reproductive toxicity in male zebrafish and associated ...epigenetic studies have not been explored. In this study, three-month-old male zebrafish were exposed to environmentally relevant concentrations of DEHP (0, 10, 33 and 100 μg/L) for 3 months, and then the impact on the reproduction of males and the underlying mechanism were investigated. Histological testing showed that an exposure concentration of 100 μg/L DEHP significantly inhibited spermatogenesis, with an associated decline in capability to fertilize untreated oocytes. Electron microscopic examinations also revealed noticeable damage to the testicular ultrastructure at the 100 μg/L DEHP exposure level. In addition, exposure to 33 and 100 μg/L of DEHP resulted in a decline of circulating testosterone (T) and an increase in the level of 17β-estradiol (E2), both of which were possibly derived from the downregulation of cyp17a1 and hsd17b3 genes and the upregulation of the cyp19a1a gene in the gonads. The DNA methylation statuses of these genes were altered within their promoter regions. A significant increase in global DNA methylation in both the male testes and their offspring larvae was observed at higher exposure concentration of DEHP. Our findings demonstrate that exposure to environmentally relevant concentrations of DEHP can damage the testes, disturbe the sex hormones production, and inhibite spermatogenesis, which ultimately impairs the reproduction of male zebrafish.
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•Investigation of long-term DEHP effects on male reproduction in zebrafish.•DEHP inhibited spermatogenesis and affected the gene-specific DNA methylation of cyp17a1, hsd17b3 and cyp19a1a in male.•DEHP increased the global DNA methylation both in male and their offspring.
This study highlights the reproductive toxicity of chronic exposure to DEHP with environmentally relevant concentrations on male zebrafish.
The Three Gorges Reservoir (TGR), one of the world's largest reservoirs, has crucial roles in flood control, power generation, and navigation. The TGR is contaminated because of the human activities, ...and how the contaminated water influences the distribution of the microbial community have not been well studied. In this study, we collected 41 freshwater samples from 13 main dwelling districts along the TGR to investigate the water quality, the distribution of the microbial community, and how water quality affects the microbial community structure. The sampling sites cover the whole TGR along the stream, with 670 km distance. Our results show that both water quality and the compositions of bacterial community vary along the TGR. The distribution of bacterial community is closely related to the local water quality. There is the highest concentration of chemical oxygen demand (COD), the highest relative abundance of Firmicutes, and the highest relative abundance of Bacillus in the upstream, compared to the middle and down streams. Redundancy analysis (RDA) showed that PO43− and COD were the main environmental factors influencing on the structure of bacterial community. The relative abundance of nitrification and denitrification functional genes also altered along the streams. These findings provide the basic data for water quality, the distribution of bacterial community, the link of environmental factors, and the bacterial community structure along the TGR, which guides the local environmental protection agency to launch protection strategy for maintaining the ecosystem health of the TGR.
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•Water quality and bacterial community compositions varied in the different sections of the TGD.•Firmicutes were the most dominant group, followed by Proteobacteria and Actinobacteria.•COD contributes to the increase of the relative abundance of Firmicutes.•PO43− and COD were the main environmental factors influencing on the distribution of bacterial community.
In plants, cytochrome P450 monooxygenase (CYP) plays an important role in detoxifying xenobiotic chemicals and coordinating abiotic stresses. Agilent 44 K rice microarray has been used to focus on ...the transcriptional profile of
osCYP
genes in rice seedling exposed to Cr solution containing K
2
CrO
4
or Cr(NO
3
)
3
. Our study showed that expression profiles of 264
osCYP
genes identified were tissue, dose and stimulus specific in rice seedlings. Comparative genomics analysis revealed that more differentially expressed
osCYP
genes were discovered in roots than in shoots under both Cr exposures. Results from Venn diagram analysis of differentially expressed
osCYP
genes demonstrated that there were common
osCYP
genes and unique
osCYP
genes present in different rice tissue as well as in different Cr treatments, which may control and/or regulate involvement of different CYP isoenzymes under Cr exposure individually or combinedly. KEGG analysis indicated that significant up- and down-regulated
osCYP
genes in rice tissues were chiefly related to “biosynthesis of secondary metabolites”. However, involvements of
osCYP
genes mapped in the “biosynthesis of secondary metabolites” were tissue and dose specific, implying their distinctly responsive and adaptive mechanisms during Cr exposure. Overall, our findings are evident to describe and clarify their individual roles of specific
osCYP
genes in regulating involvement of CYP isoforms in Cr detoxification by rice seedlings.
Agaricus bitorquis
(Quél.) Sacc. Chaidam (ABSC) is a wild edible fungus uniquely found in the Tibet Plateau. ABSC is rich in polysaccharides that are considered biologically active. This study aimed ...to determine the feasibility of enhancing exopolysaccharide (EPS) production by ABSC in shake flask culture by supplementing the fermentation medium with anthocyanin extract. Different concentrations of
Lycium ruthenicum
Murr. (LRM) anthocyanin crude extract were tested on ABSC fermentation. The activity of phosphoglucose isomerase (PGI), phosphoglucose mutase (PGM), and phosphomannose isomerase (PMI), enzymes presumably involved in EPS synthesis by ABSC, was determined. ABSC transcriptomic profile in response to the presence of anthocyanins during fermentation was also investigated. LRM anthocyanin crude extract (0.06 mg/mL) was most effective in increasing EPS content and mycelial biomass (by 208.10% and 105.30%, respectively,
P
< 0.01). The activity of PGI, PGM, and PMI was increased in a medium where LRM anthocyanin extract and its main components (proanthocyanidins and petunia anthocyanin) were added. RNA-Seq analysis showed that 349 genes of ABSC were differentially expressed during fermentation in the medium containing anthocyanin extract of LRM; 93 genes were up-regulated and 256 genes down-regulated. From gene ontology enrichment analysis, differentially expressed genes were mostly assigned to carbohydrate metabolism and signal transduction categories. Collectively, LRM anthocyanins extract positively affected EPS production and mycelial biomass during ABSC fermentation. Our study provides a novel strategy for improving EPS production and mycelial growth during ABSC liquid submerged fermentation.
Recently, the augmented utilization of silver nanoparticles (AgNPs) resulted in increasingrates of its release to aquatic environment, which potentially caused adverse effects to aquatic organisms. ...Therefore, this study investigated - reproductive toxicity and associated potential adverse outcome pathway (AOP) in zebrafish after chronic exposure to AgNPs. To serve the purpose, three-month-old adult zebrafish were exposed to different concentrations (0, 10, 33 and 100 μg/L) of AgNPs for five weeks. Exposure to 33 and 100 μg/L of AgNPs significantly decreased the fecundity in female zebrafish, accompanied by increasing apoptotic cells in the ovarian and testicular tissue using TUNEL assay. Increasing tissue burdens of AgNPs and reactive oxygen species (ROS) production were also found in both ovary and testis after five-week exposure to AgNPs. To explore the mechanism of the apoptotic pathway, the transcription levels of various genes (bax, bcl-2, caspase-3, and caspase-9) associated with the mitochondrion-mediated apoptosis pathway were examined in zebrafish after exposure to AgNPs. The results showed that the expression patterns of all the investigated genes were altered to some extent. These findings demonstrated that AgNPs exposure caused oxidative stress, induced germ cells apoptosis via mitochondrial-dependent pathway, and ultimately impaired the reproduction in zebrafish.
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•AgNPs exposure caused concentration-dependent bioaccumulation of Ag in gonad tissues.•AgNPs exposure induced ROS production and germ cell apoptosis in gonad tissues.•Adverse effects on reproductive function were observed.•An adverse outcome pathway network was applied to explore mechanistic toxicity of AgNPs.
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