Disruption of DNA-PKcs-mediated cGAS retention on damaged chromatin potentiates DNA damage-inducing agent-induced anti-multiple myeloma activity.

BACKGROUND: Targeting DNA damage repair factors, such as DNA-dependent protein kinase catalytic subunit (DNA-PKcs), may offer an opportunity for effective treatment of multiple myeloma (MM). In combination with DNA damage-inducing agents, this strategy has been shown to improve chemotherapies partially via activation of cGAS-STING pathway by an elevated level of cytosolic DNA. However, as cGAS is primarily sequestered by chromatin in the nucleus, it remains unclear how cGAS is released from chromatin and translocated into the cytoplasm upon DNA damage, leading to cGAS-STING activation. METHODS: We examined the role of DNA-PKcs inhibition on cGAS-STING-mediated MM chemosensitivity by performing mass spectrometry and mechanism study. RESULTS: Here, we found DNA-PKcs inhibition potentiated DNA damage-inducing agent doxorubicin-induced anti-MM effect by activating cGAS-STING signaling. The cGAS-STING activation in MM cells caused cell death partly via IRF3-NOXA-BAK axis and induced M1 polarization of macrophages. Moreover, this activation was not caused by defective classical non-homologous end joining (c-NHEJ). Instead, upon DNA damage induced by doxorubicin, inhibition of DNA-PKcs promoted cGAS release from cytoplasmic chromatin fragments and increased the amount of cytosolic cGAS and DNA, activating cGAS-STING. CONCLUSIONS: Inhibition of DNA-PKcs could improve the efficacy of doxorubicin in treatment of MM by de-sequestrating cGAS in damaged chromatin.

In vitro metabolism of the emerging contaminant 6PPD-quinone in human and rat liver microsomes: Kinetics, pathways, and mechanism.

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) is an ozonation product of the rubber antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD). 6PPD-Q has recently been detected in various environmental media, which may enter the human body via inhalation and skin contact pathways. However, the human metabolism of 6PPD-Q has remained unknown. This study investigated the in vitro Cytochrome P450-mediated metabolism of 6PPD-Q in human and rat liver microsomes (HLMs and RLMs). 6PPD-Q was significantly metabolized at lower concentrations but slowed at high concentrations. The intrinsic clearance (CLint) of 6PPD-Q was 21.10 and 18.58 µL min-1 mg-1 protein of HLMs and RLMs, respectively, suggesting low metabolic ability compared with other reported pollutants. Seven metabolites and one intermediate were identified, and metabolites were predicted immunotoxic or mutagenic toxicity. Mono- and di-oxygenation reactions were the main phase I in vitro metabolic pathways. Enzyme inhibition experiments and molecular docking techniques were further used to reveal the metabolic mechanism. CYP1A2, 3A4, and 2C19, especially CYP1A2, play critical roles in 6PPD-Q metabolism in HLMs, whereas 6PPD-Q is extensively metabolized in RLMs. Our study is the first to demonstrate the in vitro metabolic profile of 6PPD-Q in HLMs and RLMs. The results will significantly contribute to future human health management targeting the emerging pollutant 6PPD-Q.

Target residence of Cas9-sgRNA influences DNA double-strand break repair pathway choices in CRISPR/Cas9 genome editing.

BACKGROUND: Due to post-cleavage residence of the Cas9-sgRNA complex at its target, Cas9-induced DNA double-strand breaks (DSBs) have to be exposed to engage DSB repair pathways. Target interaction of Cas9-sgRNA determines its target binding affinity and modulates its post-cleavage target residence duration and exposure of Cas9-induced DSBs. This exposure, via different mechanisms, may initiate variable DNA damage responses, influencing DSB repair pathway choices and contributing to mutational heterogeneity in genome editing. However, this regulation of DSB repair pathway choices is poorly understood. RESULTS: In repair of Cas9-induced DSBs, repair pathway choices vary widely at different target sites and classical nonhomologous end joining (c-NHEJ) is not even engaged at some sites. In mouse embryonic stem cells, weakening the target interaction of Cas9-sgRNA promotes bias towards c-NHEJ and increases target dissociation and reduces target residence of Cas9-sgRNAs in vitro. As an important strategy for enhancing homology-directed repair, inactivation of c-NHEJ aggravates off-target activities of Cas9-sgRNA due to its weak interaction with off-target sites. By dislodging Cas9-sgRNA from its cleaved targets, DNA replication alters DSB end configurations and suppresses c-NHEJ in favor of other repair pathways, whereas transcription has little effect on c-NHEJ engagement. Dissociation of Cas9-sgRNA from its cleaved target by DNA replication may generate three-ended DSBs, resulting in palindromic fusion of sister chromatids, a potential source for CRISPR/Cas9-induced on-target chromosomal rearrangements. CONCLUSIONS: Target residence of Cas9-sgRNA modulates DSB repair pathway choices likely through varying dissociation of Cas9-sgRNA from cleaved DNA, thus widening on-target and off-target mutational spectra in CRISPR/Cas9 genome editing.

Substituent-mediated quantum interference toward a giant single-molecule conductance variation.

Quantum interference (QI) in single molecular junctions shows a promising perspective for realizing conceptual nanoelectronics. However, controlling and modulating the QI remains a big challenge. Herein, two-type substituents at different positions ofmeta-linked benzene, namely electron-donating methoxy (-OMe) and electron-withdrawing nitryl (-NO2), are designed and synthesized to investigate the substituent effects on QI. The calculated transmission coefficientsT(E) indicates that -OMe and -NO2could remove the antiresonance and destructive quantum interference (DQI)-induced transmission dips at position 2. -OMe could raise the antiresonance energy at position 4 while -NO2groups removes the DQI features. For substituents at position 5, both of them are nonactive for tuning QI. The conductance measurements by scanning tunneling microscopy break junction show a good agreement with the theoretical prediction. More than two order of magnitude single-molecule conductance on/off ratio could be achieved at the different positions of -NO2substituent groups at room temperature. The present work proves chemical substituents can be used for tuning QI features in single molecular junctions, which provides a feasible way toward realization of high-performance molecular devices.

Performance and mechanism in degradation of typical antibiotics and antibiotic resistance genes by magnetic resin-mediated UV-Fenton process.

Incomplete removal of antibiotics and antibiotic resistance genes (ARGs) has often been reported in wastewater treatment plants. More efficient treatment processes are needed to reduce their risks to the environment. Herein, we evaluated the degradation of antibiotics and ARGs by using magnetic anion exchange resin (MAER) as UV-Fenton catalyst. Sulfamethoxazole (SMZ), ofloxacin (OFX), and amoxicillin (AMX) were selected as the target compounds. The three antibiotics were almost completely degraded (> 99%) following the MAER UV-Fenton reaction for 30 min. From the degradation mechanism study, it was found that Fe3+/Fe2+ could be cyclically transferred from the catalyst at permeable interface, and the photo-generated electrons could be effectively separated. The dominant reactive radicals for antibiotics degradation were hydroxide during the MAER UV-Fenton reaction. The degradation pathway for sulfamethoxazole was proposed. In addition, wastewater samples from a wastewater treatment plant were applied to investigate the removal efficiency of antibiotics and their ARGs by the MAER UV-Fenton system. A rapid decrease in antibiotics and ARGs level was observed with this reaction system. The results from this study suggest that the MAER-mediated UV-Fenton reaction could be applied for the effective removal of antibiotics and ARGs in wastewater.

Occurrence and fate of androgens, progestogens and glucocorticoids in two swine farms with integrated wastewater treatment systems.

Steroid hormones are endocrine-disrupting chemicals that can cause adverse effects even at trace levels. The information about steroid hormones in animal wastes is still very limited. Here we investigated the occurrence and fate of fourteen androgens, twenty-one progestogens, and five glucocorticoids in Farm Luo Cheng (LC) and Farm Shui Tai (ST) with integrated wastewater treatment systems (WTSs) in South China. These two integrated systems have four stages: primary treatment (primary sedimentation tank), secondary biological treatment (biogas digester and up-flow anaerobic sludge reaction bed (UASB)), third-stage disinfection process, and fourth-stage dilution and further biodegradation process (oxidation fish ponds/lagoons). A total of 31 target steroid hormones were detected in the wastewater of the two swine farms, with concentrations ranging from 0.12 ng/L (medroxyprogesterone acetate, MPA) to 11,200 ng/L (5α-dihydroprogesterone, 5α-DHP). A total of 22 target steroid hormones were detected in feces, of which 19 were detected in Farm LC and 17 in Farm ST. Some of these detected steroids were synthetic chemicals, which might be parent chemicals from exogenous addition or their metabolites, or transformation products from other natural steroids. The steroids excretion of sows in swine farms were estimated, with some steroids such as androstenedione (AED, 41.5 µg/d), epiandrosterone (EADR, 268 µg/d), progesterone (P, 661 µg/d), and 5α-DHP (982µg/d) having much higher values than those from human bodies. Both WTSs in the swine farms could effectively remove the target steroid hormones, with the removal rates of most targets exceeding 90%. In comparison, the anaerobic digester-A2/O (anaerobic-anoxic-oxic)-lagoon system performed better in removing steroids than the up-flow anaerobic sludge reaction bed (UASB)-two-stage series (A/O)2-oxidation fish ponds system. However, there were still 22 steroid hormones, including 14 synthetic ones detected in the effluent, with the risk quotients of most synthetic steroids exceeding 1, showing high risks to aquatic organisms. The findings from this study showed that there is a wide presence of steroid hormones, especially some synthetic steroids in animal wastes, posing potential ecological risks, and these steroids should be removed before discharge to the environment.

Variation of antibiotic resistome during commercial livestock manure composting.

Composting has been widely used to turn livestock manure into organic fertilizer. However, livestock manure contains various contaminants including antibiotics and antibiotic resistance genes (ARGs). Here we investigated the variation of antibiotic resistome and its influencing factors during a commercial livestock manure composting. The results showed that composting could effectively reduce the relative abundance of ARGs and mobile genic elements (MGEs). As the dominant phylum in the composting samples, the key potential bacterial host of ARGs were Actinobacteria such as Leucobacter, Mycobacterium and Thermomonosporaceae unclassified. Meanwhile, Legionella pneumophila, Staphylococcus saprophyticus, Haemophilus ducreyi and Siccibacter turicensis may be the key potential pathogenic host of ARGs because of their co-occurrence with ARG subtypes. Redundancy analysis showed that the dissipation of ARGs during composting was linked to various environmental factors such as moisture. Bacterial succession as well as profile of biocide and metal resistance genes (BMRGs) were the determinants which constructed the antibiotic resistome during manure composting. However, the residues of ARGs and pathogens in compost products may still pose risks to human and crops after fertilization.

Microbial transformation of progesterone and dydrogesterone by bacteria from swine wastewater: Degradation kinetics and products identification.

Natural and synthetic progestogens in livestock environments have become a concern due to the frequent presence and potential adverse effects on aquatic organisms. Here we investigated the biotransformation of progestogens by wastewater-borne bacteria in the field and laboratory under oxic and anoxic conditions. The results showed that all progestogens dissipated faster under oxic conditions than under anoxic conditions, and natural progesterone transformed faster than synthetic progestogens. Meanwhile, dozens of bacterial strains capable of degrading progestogens were successfully isolated from the swine wastewater, and Bacillus sp. P19 and Bacillus sp. DGT2 were found the best for progesterone and dydrogesterone transformation, respectively. In the degradation experiments using a single bacterial strain, progesterone and dydrogesterone dissipated under oxic conditions with half-lives of 11.6 h and 18.2 h, respectively. The transformation pathways were proposed based on the identified transformation products. The findings from this study showed that progestogens can be biotransformed, but not fully mineralized in the environment.

[Contamination Characteristics and Ecological Risk Assessment of Androgens, Glucocorticoids, and Progesterone in the Liusha Bay, South China Sea].

Steroid hormones have been continuously detected and well studied in freshwater bodies in recent years, although information regarding their contamination characteristics in seawater is rare. In this paper, samples were collected in Liusha Bay, South China Sea, and the contamination characteristics, as well as the spatial distribution of 33 steroid hormones, were studied by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The results showed that 7 steroid hormones occurred with concentrations ranging from 0.003 (medroxyprogesterone, MP) to 9.023 ng·L-1(dehydroprogesterone, DGT), and from 0.017 (androsta-1,4-diene-3,17-dione, ADD) to 9.281 ng·g-1 (4-androstene-3,17-dione, AED) in seawater and sediment samples, respectively. The concentrations of detected steroid hormones were higher during wet weather than during the dry weather, and higher in the aquaculture area compared to that in the non-aquaculture area. There were no significant differences in the spatial and temporal distribution of steroid hormones in sediment. Wastewater discharge and additives in aquaculture feeds were the main routes of steroid hormones entering the marine environment. The results of the ecological risk assessment indicated that the AED posed low risk to the marine environment, whereas other steroid hormones posed no risk. Correlation analysis indicated that the concentration distribution of steroid hormones was related to salinity, water temperature, particulate matter (SS), and chemical oxygen demand (COD) in the marine environment. The results of this study contribute to the understanding of the contamination characteristics of steroid hormones in the Liusha Bay area and provide a scientific basis for ecological risk assessment and control.

Male-biased zebrafish sex differentiation and metabolomics profile changes caused by dydrogesterone.

Some progestins, including the widely used dydrogesterone (DDG), have been shown to cause male-biased sex ratio in teleost. However, there is a gap to fully understand the mechanisms of the sex differentiation disturbance by progestins, particularly from the metabolic aspect. We thus aimed to examine the sex changes by exposing zebrafish embryos to 4.4 (L), 44 (M) and 440 (H) ng/L DDG for up to 140 days, and investigated metabolomic profile changes during the critical period of sex differentiation at fry stage (35 dpf). DDG increased the percentage of male zebrafish in a dose-dependent manner, with 98% male fish in the high concentration group. In zebrafish fry, DDG increased the levels of some free fatty acids, monoglycerides, acylcarnitines, organic acids, free amino acids, while decreased lysophospholipids, uric acid and bile acids. DDG exposure also decreased the nucleoside monophosphates and UDP-sugars while increased nucleosides and their bases. These metabolite changes, namely increase in n-3 PUFAs (polyunsaturated fatty acids), myo-inositol, taurine, palmitoleic acid, oleic acid, lactic acid, fumaric acid, and uracil, and decrease in uric acid and bile acids, might account for the male-biased sex ratio in zebrafish. It appears that many of these metabolites could inhibit several pathways that regulate zebrafish gonad differentiation, including NF-κB/COX-2 and Wnt/ß-catenin pathways, and activate p53 pathway. Thus we proposed a hypothesis that DDG might induce oocytes apoptosis through the above pathways and finally lead to female-to-male sex reversal. The results from this study suggest that DDG at environmentally relevant concentrations could affect zebrafish metabolomic profiles and finally disturb fish sex differentiation.

Dydrogesterone exposure induces zebrafish ovulation but leads to oocytes over-ripening: An integrated histological and metabolomics study.

Dydrogesterone (DDG) is a synthetic progestin widely used in numerous gynecological diseases. DDG has been shown to disturb fish reproduction, however, the mechanism is still unclear. Here we studied the histological changes and differences of metabolome between exposed and control fish gonads after exposure of zebrafish (Danio rerio) embryos to 2.8, 27.6, and 289.8 ng/L DDG until sexual maturity for a total of 140 days. Dydrogesterone exposure led to male-biased zebrafish sex ratios. Histological examination revealed that DDG induced postovulatory follicles and atretic follicles in the ovary of the female fish. Postovulatory follicles indicated the occurrence of ovulation. DDG also increased spermatids and spermatozoa in the male fish testis, suggesting promotion of spermatogenesis. Ovarian metabolome showed that DDG increased the concentrations of free amino acids, urea, putrescine, free fatty acids, acylcarnitines, lysophospholipids, and other metabolites catabolized from phospholipids. Most of these metabolites are biodegradation products of proteins and lipids, suggesting the existence of ovulated oocytes over-ripening. Further, DDG upregulated arachidonic acid (AA) and its 5­lipoxygenase (5-LOX) metabolites 5­oxo­6,8,11,14­eicosatetraenoic acid (5-oxo-ETE) in the ovary, which could lead to suppression of AA cyclooxygenase (COX) metabolite prostaglandin F2α (PGF2α). It is believed that AA induced oocyte maturation, while 5-oxo-ETE and related metabolites in purinergic signaling promoted ovulation. Whereas, the suppression of PGF2α production might block spawning and damaged follicular tissue digestion, which explained the oocytes over-ripening and atretic follicles in the treated ovary. Overall, our results suggested that DDG exposure induced zebrafish oocyte maturation and ovulation but led to oocytes over-ripening via the AA metabolic pathway and purinergic signaling.

Medroxyprogesterone acetate affects sex differentiation and spermatogenesis in zebrafish.

Medroxyprogesterone acetate (MPA) is a widely used synthetic progestin and it has been frequently detected in aquatic environments. However, its effects on aquatic organisms remain largely unknown. Here we investigated the chronic effects of MPA on sex differentiation and gonad development in zebrafish. Zebrafish larvae at 20 days post fertilization (dpf) were exposed to 4.32, 42.0, and 424 ng L-1 of MPA until they reached 140 dpf. The results showed that chronic exposure to 42.0 ng L-1 of MPA caused 60% proportion of males as well as significant up-regulation of dmrt1 (˜1.79 fold) and hsd17b3 (˜1.92 fold). Histological analysis showed MPA significantly increased the frequency of immature spermatocytes accompanied with the increased transcription of dmrt1 (˜2.06 fold) and ar (˜1.73 fold) in the testes. Meanwhile, MPA exposure significantly increased the transcription of lhb at all exposure concentrations in the males. In contrast, it significantly suppressed the transcription of lhb (˜-8.06-fold) and fshb (˜-6.35-fold) at 42.0 ng L-1 in the females. Collectively our results demonstrated that MPA had androgenic activity, and could affect sex differentiation and spermatogenesis in zebrafish at environmentally relevant concentrations. The findings from this study suggest that MPA in the aquatic environment may pose potential androgenic risks to fish populations.

Long Intergenic Non-Protein-Coding RNA 01138 Accelerates Tumor Growth and Invasion in Gastric Cancer by Regulating miR-1273e.

BACKGROUND The treatment and nursing of gastric cancer (GC) remains an enormous challenge in clinical practice. Understanding the potential mechanisms of the pathogenesis of GC would improve GC therapy. Long intergenic non-protein-coding RNA 01138 (LINC01138) was reported to promote the progression of hepatocellular carcinoma; however, whether it is involved in GC progression has been unclear. MATERIAL AND METHODS Expressions of LINC01138 and miR-1273e in GC tissues and cell lines were measured by qRT-PCR assay. The interaction between LINC01138 and miR-1273e was predicted by the online tool miRDB, verified by dual-luciferase reporter and RNA pulldown assays. Effects of LINC01138 knockdown or miR-1273e overexpression on cell viability, proliferation, apoptosis, invasion, and migration were evaluated by MTT, colony formation assay, flow cytometry, and Transwell assays. Target genes of miR-1273e were predicted by KEGG analysis, and involvement of the mitogen-activated protein kinase (MAPK) pathway was confirmed by qRT-PCR assay. RESULTS LINC01138 was increased but miR-1273e was decreased in GC tissues and cell lines. Knockdown of LINC01138 suppressed GC cell viability, proliferation, invasion, and migration, and promoted GC cell apoptosis. We demonstrated that LINC01138 contributed to GC progression by directly sponging and inhibiting miR-1273e. Moreover, the MAPK pathway was verified to participate in the promotive effects of LINC01138 on GC progression. CONCLUSIONS LINC01138 activated the MAPK signaling pathway by inhibiting miR-1273e to promote GC cell proliferation, invasion, and migration, and inhibit GC cell apoptosis, suggesting that the LINC01138/miR-1273e/MAPK axis is a promising therapeutic target for GC.

Persistence of androgens, progestogens, and glucocorticoids during commercial animal manure composting process.

Animal manure contains various organic contaminants such as steroids. The fate of these steroids during composting is still unknown. Here we investigated the fate of androgens, progestogens, and glucocorticoids during animal manure composting and evaluated their residues in compost-applied soils. The results showed the presence of 16 steroid hormones in the initial compost with concentrations ranging from 3.26 ng/g dw (Cortisol) to 2520 ng/g dw (5α-dihydroprogesterone). The concentrations of almost all detected hormones increased on the 2nd day of composting, and some of them increased several or even dozens of times. Steroids such as hydroxyprogesterone caproate, melengestrol acetate, and methyltestosterone were not found in the initial compost but later detected during the composting process. After 171 days of composting, only 40.4% of detected steroid hormones was removed, and the total concentration of detected steroids was still as high as 3210 ng/g dw. The removal rates of some target compounds were negative, especially for the natural androgens androsta-1,4-diene-3,17-dione and the synthetic androgen 17ß-boldenone whose concentrations significantly increased by the end of composting, indicating conversion from their conjugates or transformation from other steroids. The steroid hormones were mainly eliminated in the first three weeks; prolonged composting time did not obviously promote further removal. The variations in steroid concentration were related to the changes in compost properties such as pH and temperature during the composting process. The dissipation of steroid hormones was also linked to the changes of microbial communities in the compost to some extent. Twelve steroids were detected in the compost-treated soils of a kailyard, while 26 steroid hormones were detected in the roots of Chinese cabbages grown on the soil. The results suggest that the application of manure compost product can lead to soil contamination and plant uptake.

Fate of veterinary antibiotics during animal manure composting.

Antibiotics are widely used in animals for disease treatment and prevention. After use, these antibiotics end up in manure. Here we investigated the fate of veterinary antibiotics in animal manure during composting and their residues in manure-applied soils. The results showed that 64.7% of the detected veterinary antibiotics were removed after composting for 171 days, which mainly occurred at the thermophilic phase in the second week, followed by a long stable stage with limited variations. The removal rates for lincomycin, trimethoprim and the macrolides during the composting were >89.7%, while those for the sulfonamides, tetracyclines and fluoroquinolones were less than <63.7%. The dissipation of antibiotics during the composting was related to the change of compost physicochemical properties, especially moisture and C/N ratio. The application of compost products with antibiotic residues could still lead to soil contamination, which may pose risks of resistance selection to the soil ecosystem.

Dydrogesterone affects the transcription of genes in GnRH and steroidogenesis pathways and increases the frequency of atretic follicles in zebrafish (Danio rerio).

Dydrogesterone (DDG) is a synthetic progestin broadly used in human and veterinary medicine and has been widely detected in aquatic environments. However, its potential effects on aquatic organisms are little documented. Here we investigate the short-term effects of DDG on the transcriptional and histological responses in adult zebrafish (Danio rerio). Adult zebrafish were exposed to 32.0, 305 and 2490 ng L-1 of DDG for 14 days. Real time quantitative PCR analysis showed that DDG significantly increased transcripts of most genes involved in the gonadotropin-releasing hormone (GnRH) pathway in the brain of female. In contrast, apparent down-regulation of these gene transcriptions was observed in the brain of males. The transcription of cyp19a1a in the ovary had a 2.3 fold increase at 2490 ng L-1 of DDG and the transcription of hsd17b2 at 305 and 2490 ng L-1 in the testis was enhanced by approximately 2.0 fold and 2.4 fold, respectively. Histopathological analysis revealed exposure to 2490 ng L-1 DDG significantly increased the percentage of atretic follicles in the ovary. The results of this study suggest that DDG has potential endocrine disrupting effects and affects the ovarian development in zebrafish.

Degradation of climbazole by UV/chlorine process: Kinetics, transformation pathway and toxicity evaluation.

Climbazole is an antifungal agent widely used in household personal care products, and it was found persistent in chlorination disinfection process. Here we investigated the kinetics and mechanism of climbazole degradation by UV/chlorine process. The results showed that the UV/chlorine process dramatically enhanced degradation of climbazole when compared to the UV photolysis and chlorination alone. The neutral condition (pH 7) produced the highest reaction rate for the climbazole by UV/chlorine among the various pH conditions. Dissolved organic matter and inorganic ions in natural water showed moderate inhibition effects on the degradation of climbazole in the UV/chlorine process. Hydroxyl radical (OH and chlorine radical (Cl) were found to be the main reactive species in the degradation of climbazole, with the second-order rate constant of 1.24 × 1010 M-1 s-1 and 6.3 × 1010 M-1 s-1, respectively. In addition, the OH and Cl in the UV/chlorine at 100 µM accounted for 82.2% and 7.7% contributions to the removal of climbazole, respectively. Eleven of main transformation products of climbazole were identified in the UV/chlorine process. These oxidation products did not cause extra toxicity than climbazole itself. The findings from this study show that the combination of chlorination with UV photolysis could provide an effective approach for removal of climbazole during conventional disinfection process.

Dydrogesterone Causes Male Bias and Accelerates Sperm Maturation in Zebrafish ( Danio rerio).

Synthetic progestins are widely used in human and veterinary medicine. They can enter aquatic environments mainly via wastewater discharge and agricultural runoff, thus affecting fish populations in receiving waters. Here, we investigated the chronic effects of dydrogesterone (DDG) on zebrafish from 21 to 140 days post-fertilization (dpf) at 3.39, 33.1, and 329 ng L-1. The results showed that the male ratio increased with the exposure concentration, and after 120 days of exposure to 329 ng L-1, 98% of the fish were males. The DDG exposure during sex differentiation significantly increased the transcription of dmrt1 (1.83-fold) and apoptosis-related genes but suppressed the transcription of cyp19a1a (3.16-fold). Histological analysis showed that the exposure to DDG at 329 ng L-1 caused 61.5% of mature spermatocytes in males, while the exposure to DDG at 33.1 ng L-1 resulted in 14.7% of atretic follicles in females. Microarray analysis identified spermatogenesis-related gene ontology (endothelial barrier and immune response) in the testes at all concentrations. Genes from phagosome, lysosome, and sphingolipid metabolism pathways were enriched and could be responsible for sperm maturation. The findings from this study demonstrate that DDG in the aquatic environment can cause male bias and accelerate sperm maturation in zebrafish, resulting in potential high ecological risks to fish populations.

Occurrence, fate and mass loadings of antibiotics in two swine wastewater treatment systems.

Antibiotics are widely applied in livestock industry to prevent or treat animal diseases. However, those antibiotics are poorly metabolized in livestock animals, most of them being excreted via feces or urine. Hence we need to understand the removal of antibiotics in swine farm wastewater treatment systems. This study investigated occurrence and fate of various antibiotics in two full-scale swine farm wastewater treatment systems (Farm A: anaerobic digester-A2/O-lagoon; Farm B: upflow anaerobic sludge blanket (UASB)-(A/O)2-lagoon). The results showed the presence of 25 antibiotics out of 40 target antibiotics in the wastewater and sludge samples from the two farms. In Farm A, sulfamonomethoxine, sulfachlorpyridazine, oxytetracycline and lincomycin were predominant in the influent with concentrations up to 166 ±â€¯3.64 µg/L, while in the dewatered sludge chlortetracycline, oxytetracycline, tetracycline and norfloxacin were the predominant target compounds with concentrations up to 29.2 ±â€¯3.74 µg/g. In Farm B, high concentrations (up to 3630 ±â€¯1040 µg/L) of sulfachlorpyridazine, sulfamonomethoxine and lincomycin were detected in the influent, and the predominant target antibiotics detected in the dewater sludge were similar to those in Farm A, with concentrations up to 28.6 ±â€¯0.592 µg/g. The aqueous removal rates for the total antibiotics were >99.0% in the wastewater treatment plants of both farms. Among a series of treatment units, the anaerobic digester in Farm A and UASB in Farm B made a significant contribution to the elimination of the target antibiotics from the animal wastewater. The daily mass loadings of total antibiotics in the manure, influent, dewatered sludge and effluent were 17.1, 28.0, 2.53, and 0.0730 g/d for Farm A and 24.5, 354, 3.17, and 0.293 g/d for Farm B. The full-scale swine wastewater treatment facilities could effectively remove antibiotics from swine wastewater, but the dewatered sludge needs to be further treated before disposal on land.

Occurrence, fate and risk assessment of androgens in ten wastewater treatment plants and receiving rivers of South China.

Androgens are one class of steroids that could cause endocrine disrupting effects in aquatic organisms. However, little information is available about androgens in wastewater treatment plants (WWTPs) with different treatment technologies. Here we investigated the occurrence, removal, and fate of fourteen natural and synthetic androgens in ten WWTPs of Guangdong province, south China. The results showed detection of ten androgens in the influents of the ten WWTPs, with concentrations up to 4650 ng/L (androsta-1,4-diene-3,17-dione). But only three androgens androsta-1,4-diene-3,17-dione, 4-androstene-3,17-dione and 17ß-boldenone were detected in the final effluents of the ten WWTPs, while six androgens androsta-1,4-diene-3,17-dione (N.D. to 43.0 ng/g), 4-androstene-3,17-dione (2.06-42.7 ng/g), epi-androsterone (N.D. to 506 ng/g), testosterone (0.29-4.24 ng/g), 17ß-boldenone (N.D. to 2.05 ng/g) and methyl testosterone (N.D. to 0.70 ng/g) were found in activated sludge. The aqueous phase removal rates for most androgens in the WWTPs exceeded 95% except for 4-androstene-3,17-dione with its removal rates varying between 79.5% and 100%. The removal of androgens in the WWTPs could be attributed mainly to biodegradation while removal by precipitation, volatilization, sludge absorption and oxidation was very limited. Eight androgens were also found in five receiving rivers. The risk quotients of some androgens (androsta-1,4-diene-3,17-dione, 4-androstene-3,17-dione, methyl testosterone, 17α-trenbolone) exceeded 1 in the receiving rivers, showing high risks to aquatic organisms. Further studies are needed to understand the origin of these high risk androgens and ecological effects.