Overexpression of RpKTI2 from Robinia pseudoacacia Affects the Photosynthetic Physiology and Endogenous Hormones of Tobacco.

Kunitz trypsin inhibitor genes play important roles in stress resistance. In this study, we investigated RpKTI2 cloned from Robinia pseudoacacia and its effect on tobacco. RpKTI2 was introduced into the tobacco cultivar NC89 using Agrobacterium-mediated transformation. Six RpKTI2-overexpressing lines were obtained. Transgenic and wild-type tobacco plants were then compared for photosynthetic characteristics and endogenous hormone levels. Transgenic tobacco showed minor changes in chlorophyll content, fluorescence, and photosynthetic functions. However, the maximum photochemical efficiency (Fv/Fm) increased significantly while intercellular CO2 concentration (Ci) decreased significantly. Stomatal size and hormone content (indole-3-acetic acid, zeatin riboside, gibberellin, and indole-3-propionic acid) were reduced, while brassinosteroid content increased. Random forest regression revealed that RpKTI2 overexpression had the biggest impact on carotenoid content, initial fluorescence, Ci, stomatal area, and indole-3-acetic acid. Overall, RpKTI2 overexpression minimally affected chlorophyll synthesis and photosynthetic system characteristics but influenced stomatal development and likely enhanced the antioxidant capacity of tobacco. These findings provide a basis for future in-depth research on RpKTI2.

Association between depression and diabetes mellitus and the impact of their comorbidity on mortality: Evidence from a nationally representative study.

BACKGROUND: Depression and diabetes mellitus (DM) are major chronic noncommunicable diseases that impair one's mental and physical well-being and impose substantial burdens on the health system. Depressed individuals have an increased risk of impaired blood glucose, weight gain and dyslipidemia which could induce poorer long-term survival. METHODS: 37,040 individuals from the National Health and Nutrition Examination Survey (NHANES) were included. Depressive symptoms were assessed by the Patient Health Questionnaire (PHQ-9) and classified by the total scores as no (0-4), mild (5-9), moderate (10-14), and severe (15-27). DM was determined based on self-reported medical history, clinical test results, and medication use. Logistic and Cox regression were the main statistical models. All analyses were based on weighted data from complex sampling. RESULTS: The prevalence of DM was higher in depressed than non-depressed individuals (21.26 % vs. 13.75 %). The adjusted odds ratio (OR) (95 % CI) of comorbid DM increased with depression severity, from 1.00 (reference) for no depression, to 1.22 (1.09,1.36) for mild, 1.62 (1.37,1.92) for moderate, and 1.52(1.28,1.82) for severe depression. Comorbidity of DM and depression significantly associated with a higher risk of all-cause mortality, with a hazard ratio (HR) (95 % CI) = 2.09 (1.64,2.66). LIMITATIONS: Dynamic demographic and metabolic data were not available. CONCLUSION: Depression is associated with a higher risk of DM, which may be related to biological, socioeconomic, and medication-related factors. Comorbidity of the two worsens long-term survival. Therefore, blood glucose management and prevention of DM should be emphasized in depressed patients.

Exogenous chelating agents influence growth, physiological characteristics and cell ultrastructure of Robinia pseudoacacia seedlings under lead-cadmium stress.

Heavy metal pollution of soil, especially by lead (Pb) and cadmium (Cd), is a serious problem worldwide. The application of safe chelating agents, combined with the growing of tolerant trees, constitutes an approach for phytoremediation of heavy-metal-contaminated soil. This study aimed to determine whether the two safe chelators, tetrasodium glutamate diacetate (GLDA) and citric acid (CA), could improve the phytoremediation capacity of black locust (Robinia pseudoacacia L.) in a Pb-Cd-contaminated soil and to find the key factors affecting the biomass accumulation of stressed black locust. In Pb- and Cd-stressed black locust plants, medium- and high-concentration GLDA treatment inhibited the growth, chlorophyll synthesis and maximum photochemical efficiency (Fv/Fm), promoted the absorption of Pb and Cd ions and resulted in the shrinkage of chloroplasts and starch grains when compared with those in Pb- and Cd-stressed plants that were not treated with GLDA. The effects of CA on plant growth, ion absorption, chlorophyll content, chlorophyll fluorescence and organelle size were significantly weaker than those of GLDA. The effect of both agents on Cd absorption was greater than that on Pb absorption in all treatments. The levels of chlorophyll a and plant tissue Cd and rates of starch metabolism were identified as the key factors affecting plant biomass accumulation in GLDA and CA treatments. In the future, GLDA can be combined with functional bacteria and/or growth promoters to promote the growth of Pb- and Cd-stressed plants and to further improve the soil restoration efficiency following pollution by heavy metals. Application of CA combined with the growing of black locust plants has great potential for restoring the Cd-polluted soil. These findings also provide insights into the practical use of GLDA and CA in phytoremediation by R. pseudoacacia and the tolerant mechanisms of R. pseudoacacia to Pb-Cd-contaminated soil.

The impact of boarding schools on the development of cognitive and non-cognitive abilities in adolescents.

BACKGROUND: Since China adopted a policy to eliminate rural learning centers, boarding has become an important feature of the current rural student community. However, there is a lack of consensus on the impact of boarding schools on students' cognitive and non-cognitive development. This study investigates the effect of boarding schools on the development of cognitive and non-cognitive abilities of junior high school students in rural northwest China. METHODS: Using a sample of 5,660 seventh-grade students from 160 rural junior high schools across 19 counties, we identify a causal relationship between boarding and student abilities with the instrumental variables (IV) approach. RESULTS: The results suggest that boarding positively influences memory and attention, while it has no significant effect on other cognitive abilities such as reasoning, transcription speed, and accuracy. Furthermore, we find no significant association between boarding and the development of non-cognitive skills. CONCLUSIONS: Given the widespread prevalence of boarding schools in rural regions, our study highlights the growing importance of improving school management to promote the development of students' cognitive abilities and integrating the development of non-cognitive or social-emotional abilities into students' daily routines.

Effects of the emerging contaminant 1,3,6,8-tetrabromocarbazole on the NF-κB and correlated mechanism in human hepatocellular carcinoma cells.

1,3,6,8-Tetrabromocarbazole (1368-BCZ) is identified as an emerging contaminant that exerts angiogenic effects. Multiple studies indicated there was a positive correlation between angiogenesis and nuclear factor kappa B (NF-κB) activation. While the role of NF-κB in inflammation and apoptosis has been well known, the potential biological effects of 1368-BCZ on NF-κB signaling and related mechanism remain unclear. We, therefore, explored the possible effects of 1368-BCZ on the NF-κB pathway at the gene and protein levels and confirmed that NF-κB activation by 1368-BCZ exposure caused an augmented phosphorylated protein level, induction of NF-κB response element (κBRE)-driven luciferase activity and upregulation of transcriptional level of downstream responsive genes. Although 1368-BCZ did not produce detectable changes in hepatic fibrosis in vivo, it obviously altered the apoptosis in human hepatocellular carcinoma (HepG2) cells. Furthermore, the induction of apoptosis was confirmed by the increased cleaved caspase-3 level. These data revealed the activating effects of 1368-BCZ on NF-κB and its involvement in the underlying mechanisms, providing additional information for toxicology studies of emerging contaminants and introducing a mechanism-based toxicological evaluation of emerging pollutants.

[Determination of dazomet and its metabolite methyl isothiocyanate residues in plant-derived foods by gas chromatography-triple quadrupole mass spectrometry].

Dazomet is a kind of crystal solid that is stable at room temperature and acts as a fumigant. It is commonly used to control soil fungi, as an insecticide, and in sterilization and weeding. It can effectively kill root-knot nematodes, soil pests, weeds, and many soil-borne disease-causing organisms, to provide clean and healthy soil. Dazomet slowly decomposes and releases methyl isothiocyanate, methylamine, carbon disulfide, and hydrogen sulfide in acidic soil, and diffuses upward through the spaces in the soil to kill contact organisms. When agricultural crops are planted in soil treated with cotton wool, the residues in the grown crop can cause harm to human body when consumed. To ensure the quality and safety of food crops, it is important to develop a detection method for dazomet and its metabolites in plant-derived foods. Hence, in this study, a rapid and simultaneous determination method was developed for dazomet and its metabolite methyl isothiocyanate residues in plant-derived foods by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). The sample pretreatment and chromatographic conditions were optimized in the experiment. Subsequently, dazomet and its metabolite methyl isothiocyanate residues in vegetables, fruits, grains, nuts, tea, and spices were extracted with ethyl acetate, and purified using graphitized carbon, a primary-secondary amine, stearyl-bonded silica gel, and anhydrous magnesium sulfate as dispersive solid-phase extraction sorbents. After centrifugation and filtration, the target compounds were analyzed in the multiple reaction monitoring (MRM) mode by GC-MS/MS, and quantified by matrix matching external standard method. The matrix effects of the samples were also evaluated. The matrix effect was found to be in the range of 2.5% to 13.6% for methyl isothiocyanate in 16 matrices. As this matrix effect was weak, there was no need for compensatory measures. In contrast, the matrix effect of dazomet in 16 matrices was in the range of 240.3% to 331.2%. This matrix effect was strong and required compensation. Finally, a matrix matching calibration method was used to compensate the matrix effects. The relative matrix effects of other tested substrates were analyzed using lettuce as the representative substrate; it was found that all showed weak matrix effects. Therefore, the use of lettuce as a representative matrix to prepare a matrix standard curve can effectively correct the matrix effects of dazomet and methyl isothiocyanate in other substrates. Under the optimal conditions, the calibration curves were linear in the range of 0.005-1 mg/L with correlation coefficients higher than 0.99. Recovery tests were conducted by adding mixed standards to blank samples at four levels. The recoveries were in the range of 74.2%-117.2% with relative standard deviations (RSDs, n=6) of 2.8%-9.0%. The limits of quantification (LOQs) of dazomet and methyl isothiocyanate were 0.01 mg/kg. The accuracy and precision of this method met the requirements of pesticide residue determination. The established method was used to detect dazomet and its metabolite methyl isothiocyanate residues in six samples of Chinese cabbage, Chinese chives, cowpea, lettuce, eggplant, ginger, celery, potato, orange, kiwifruit, tomato, chili, rice, tea, almond, and Cuminum cyminum L. in the laboratory, and nothing was detected. The method is simple, rapid, and sensitive; overcomes the shortcomings of existing methods that require two pretreatment steps and two sets of equipment; and meets the requirements for the detection of dazomet and its metabolite methyl isothiocyanate residues in plant-derived foods.

Effect-directed analysis of estrogenic chemicals in sediments from an electronic-waste recycling area.

Electronic waste (e-waste) pollution is of great concern due to the release of hazardous chemicals during the improper e-waste disposal. Many chemicals leached from e-waste were reported to pose estrogenic effects. To date, little is known regarding the occurrence and biological effects of estrogenic chemicals in sediments near an e-waste area. In this study, an effect-directed analysis (EDA) is applied to determine the estrogenic chemicals in sediments of four sites collected from a typical e-waste recycling city in China. Following screening with the ER-CALUX assay, the extract of sample with the most potent effect was subjected in fractionation using reverse phase liquid chromatography. Based on a target analysis for the active fractions, four compounds, including estrone, 17ß-estradiol, 17α-ethinylestradiol and bisphenol A, were identified, and these contributed to 17% of the total toxic effects in the sample. A further nontarget analysis screened four candidates, namely diethylstilbestrol (DES), hexestrol (HES), nandrolone and durabolin, and the total contribution was found to be 48% from the active sample. Specifically, DES and HES were only detected in the active sample and were found to be the primary drivers of estrogenic effects. An examination of the identified chemicals in the four sites indicated that these estrogenic chemicals may originate from e-waste recycling, livestock excretion and domestic waste. These findings uncovered the estrogenic pollutants in sediments from an e-waste area. Considering single endpoint in biological assay is not abundant to screen chemicals with different toxic effects, further EDA studies with multiple endpoints are required to better understand the occurrence of representative or unknown chemicals in e-waste-polluted areas.

Application of a ready-to-use cell sensor for dioxins and dioxin-like compounds screening in foodstuffs.

Dioxins and dioxin-like compounds (DLCs) in foodstuffs are closely related to human health. As China is the largest food-consuming country, there is a potentially large demand for screening bioassays that are rapid, cost-effective and capable of determining dioxins and DLCs in foodstuffs. CBG2.8D is a reporter gene-based recombinant cell sensor that was recently developed for determining dioxin and DLCs in ambient and seafood samples. In this study, we established a bioanalytical method with this ready-to-use cell sensor for the bioanalysis of dioxins and DLCs in different types of meat samples. Twenty-nine samples from three typical types of meat (beef, pork and fish) were collected and subjected to both instrumental analysis and a CBG2.8D bioassay. The intra- and inter-lab reproducibility of the bioassay was investigated and the coefficients of variation (CVs) were lower than 25%, suggesting that the cell sensor had a good reproducibility for the meat samples. Based on the correlation equation and coefficient obtained by comparing the data from the instrumental analysis and CBG2.8D bioassay, we found that this method had better performance with pork and fish than with beef. The compliance rate was also determined by comparing the results from the instrumental analysis and there were no false results for the pork and fish samples. Lastly, a complete operation procedure was summarized as a guideline for practical application. In conclusion, the CBG2.8D cell sensor exhibits excellent stability and is capable of screening dioxins and DLCs in meat samples.

GNL3 Regulates SIRT1 Transcription and Promotes Hepatocellular Carcinoma Stem Cell-Like Features and Metastasis.

The expression of GNL3 in hepatocellular carcinoma was detected, and its effect on the proliferation and metastasis of hepatocellular carcinoma cells was investigated. Hepatocellular carcinoma and adjacent tissues were collected. The mRNA and protein expression levels of GNL3 were detected by qRT-PCR, Western blot, and immunohistochemistry. The relationship between GNL3 and the prognosis of liver cancer was analysed using public databases. A GNL3 interfering plasmid was constructed, and the effects of GNL3 on the proliferation of HepG2 and PLC-PRF-5 hepatoma cells were detected by the CCK-8 method. Transwell chamber assays were used to detect the effects of GNL3 on the migration and invasion of hepatocellular carcinoma cells. The effects of GNL3 on SIRT1 expression and stem cell markers were analysed. The effect of GNL3 on the proliferation of hepatocellular carcinoma was detected in a subcutaneous tumor-bearing animal model. The results showed that the mRNA and protein levels of GNL3 were higher than those of adjacent tissues. The overall survival (OS) of HCC patients with high GNL3 expression was worse. In vivo and in vitro experiments confirmed that silencing GNL3 could inhibit the proliferation, migration, and invasion of hepatocellular carcinoma cells. Mechanistic studies have shown that GNL3 regulates SIRT1 expression. GNL3 mediates the stem cell-like properties of HCC cells through SIRT1. In conclusion, this study found that GNL3 increased expression in hepatocellular carcinoma, which promoted the malignant biological behavior of hepatocellular carcinoma cells and was related to the cell dry phenotype. This study has certain significance in evaluating the prognosis of HCC patients.

Emodin inhibits U87 glioblastoma cells migration by activating aryl hydrocarbon receptor (AhR) signaling pathway.

Aryl hydrocarbon receptor (AhR) is a ligand-activated receptor to mediates the biological reactions of many environmental and natural compounds, which is highly expressed in glioblastoma. Although it has been reported that AhR agonist emodin can suppress some kinds of tumors, its inhibitory effect on glioblastoma migration and its relationship with AhR remain unclear. Based on the complexity of tumor pathogenesis and the tissue specificity of AhR, we hope can further understand the effect of emodin on glioblastoma and explore its mechanism. We found that the inhibitory effect of emodin on the migration of U87 glioblastoma cells increased with time, and the cell migration ability was inhibited by about 25% after 36 h exposure. In this process, emodin promoted the expression of the tumor suppressor IL24 by activating the AhR signaling pathway. Reducing the expression of AhR or IL24 by interfering RNA could block or relieve the inhibitory effect of emodin on the U87 cells migration, which indicates the inhibition of emodin on the migration of glioblastoma is mediated by the AhR-IL24 axis. Our data proved the AhR-IL24 signal axis is an important pathway for emodin to inhibit the migration of glioblastoma, and the AhR signaling pathway can be used as a key target to research the regulation effect and its mechanism of compounds on glioblastoma migration.

Multi-walled carbon nanotubes inhibit potential detoxification of dioxin-mediated toxicity by blocking the nuclear translocation of aryl hydrocarbon receptor.

Despite numerous studies on effects of environmental accumulation of nano-pollutants, the influence of nanoparticles on the biological perturbations of coexisting pollutants in the environment remained unknown. The present study aimed at elucidating the perturbations of six environmental nanoparticles on detoxification of dioxin-induced toxicity at cellular level. We discovered that there was no remarkable difference in the cell uptake and intracellular distributions of these six nanoparticles. However, they have different effects on the detoxification of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD). Multi-walled carbon nanotubes (MWCNTs) inhibited the translocation of aryl hydrocarbon receptor (AhR) from cytosol to the nucleus, leading to the downregulation of cytochrome P450 family 1 subfamily A member 1 (CYP1A1) and inhibition of detoxification function. These findings demonstrate that MWCNTs can impact the potential detoxification of dioxin-induced toxicity through modulating AhR signaling pathway. Co-exposures to MWCNTs and dioxin may cause even more toxicity than single exposure to dioxin or MWCNTs alone.

Hydroxyphenyl Butanone Induces Cell Cycle Arrest through Inhibition of GSK3ß in Colorectal Cancer.

BACKGROUND: Colorectal cancer (CRC) is among the top three gastrointestinal malignancy in morbidity and mortality. The abnormal activation of Wnt/ß-catenin pathway is considered to be a key factor in the occurrence and development of CRC. Novel inhibitor discovery against key factor in WNT pathway is important for CRC treatment and prevention. METHODS: Cell proliferation was detected after hydroxyphenyl butanone treatment in human colorectal cancer HCT116, LOVO, and normal colonic epithelial NCM460 cells. Colony formation, cell invasion ability, and cell cycle were detected with and without GSK-3ß knockdown. RESULTS: Hydroxyphenyl butanone induces cycle arresting on G1-S phase of colorectal cancer cell line through GSK3ß in Wnt/ß-catenin pathway and inhibits malignant biological manifestations of cell proliferation, colony formation, and invasion. The inhibition in the high concentration group is stronger than that in the low concentration group, and the antitumor effect is different for different tumor cells. Under the same concentration of natural hydroxyphenyl butanone, the inhibition on normal colonic epithelial cells is significantly lower than that on tumor cells. The natural hydroxyphenyl butanone with medium and low concentration could promote the proliferation of normal colonic epithelial cells. CONCLUSION: This study illustrated natural hydroxyphenyl butanone as new inhibitor of GSK3ß and revealed the mechanisms underlying the inhibitory effects in colorectal cancer.

Polarizability and aromaticity index govern AhR-mediated potencies of PAHs: A QSAR with consideration of freely dissolved concentrations.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants associated with adverse human effects including cancer, and the aryl hydrocarbon receptor (AhR) is a key ligand-activated transcription factor mediating their toxicity. However, there is presently a lack of data on AhR potencies of PAHs. Simple, transparent, interpretable and predictive quantitative structure-activity relationship (QSAR) models are helpful, especially with the consideration of freely dissolved concentrations linked to bioavailability. Here, QSAR models on AhR-mediated luciferase activity of PAHs were developed with nominal median effect concentrations (EC50, nom) and freely dissolved concentration (EC50, free) as endpoints, and quantum chemical and Dragon descriptors as predictor variables. Results indicated that only the EC50, free model met the acceptable criteria of QSAR model (determination coefficient (R2) > 0.600, leave-one-out cross validation (QLOO2) > 0.500, and external validation coefficient (QEXT2) > 0.500), implying that it has good goodness-of-fit, robustness and external predictive power. Molecular polarizability and aromaticity index reflecting the partition behavior and intermolecular interactions can effectively predict AhR-mediated potencies of PAHs. The results highlight the necessity of adoption of the freely dissolved concentration in the QSAR modeling and more in silico models need to be further developed for different animal models (in vivo or in vitro).

Simple and rapid determination of dioxin in fish and sea food using a highly sensitive reporter cell line, CBG 2.8D.

Food, especially animal origin food is the main source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) for human exposure. So, a simple, rapid and cheap bioassay method is needed for determination of dioxins in food samples. In this study, we used a new highly sensitive reporter cell line to determine the concentration of dioxins in 33 fish and seafood samples. The samples were extracted by shaking with water/isopropanol (1:1 v/v) and hexane and cleaned-up by a multi layered silica gel column and an alumina column, then analyzed using CBG 2.8D cell line. We compared the results obtained from the CBG 2.8D cell assay to those obtained from conventional High-Resolution Gas Chromatography-High Resolution Mass Spectrometry (HRGC-HRMS) analysis. Good correlations were observed between these two methods (r2=0.93). While the slope of regression line was 1.76, the bioanalytical equivalent (BEQ) values were 1.76 folds higher than WHO-TEQ values and the conversion coefficient was 0.568 (the reciprocal of 1.76). In conclusion, CBG 2.8D cell assay was an applicable method to determine dioxins levels in fish and sea food samples.

2,3,7,8-Tetrachlorodibenzo-p-dioxin and up-regulation of neurofilament expression in neuronal cells: Evaluation of AhR and MAPK pathways.

Dioxin exposure is reported to affect nervous system development and increase the risk of neurodegenerative diseases. Generally, dioxin exerts its neurotoxicity via aryl hydrocarbon receptor (AhR). Neurofilament (NF) light (NFL) protein is a biomarker for both neuronal differentiation and neurodegeneration and its expression is controlled by the mitogen-activated protein kinase (MAPK) pathway. However, the effects of dioxin on NFL expression and involved mechanisms are incompletely understood. We aimed to investigate the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on NFL expression and elucidate the underlining signaling pathways and their potential crosstalk, specifically between MAPK and AhR pathway. We employed primary cultured rat cortical neurons to evaluate the effect of TCDD exposure on NFL expression. We also used nerve growth factor (NGF)-treated PC12 cells with specific inhibitors to investigate the involvement of and potential crosstalk between the MAPK pathway and the AhR pathway in mediating the effects of TCDD on NFL expression. After TCDD exposure, NFL mRNA and protein levels were upregulated in cultured neurons. NFL protein was preferentially found in the cell body compared with neurites of the cultured neurons. In PC12 cells, TCDD enhanced both NGF-induced NFL expression and phosphorylation of ERK1/2 and p38. The addition of MAPK-pathway inhibitors (PD98059 and SB230580) partially blocked the TCDD-induced NFL upregulation. CH223191, an AhR antagonist, reversed the upregulation of NFL and phosphorylation of ERK1/2 and p38 induced by TCDD. This study demonstrated TCDD-induced upregulation of NFL in cultured neurons, with protein retained in the cell body. TCDD action was dependent on activation of AhR and MAPK, while crosstalk was found between these two signaling pathways.

Regulation of Aryl Hydrocarbon Receptor Signaling Pathway and Dioxin Toxicity by Novel Agonists and Antagonists.

Dioxins, mostly through activation of aryl hydrocarbon receptor (AhR), are potent toxic substances widely distributed in the environment, while moderated suppression of AhR also exhibits anti-tumor effects. Therefore, the proper modulation of AhR activity may counteract AhR-mediated toxicities and certain diseases. In this investigation, we identified several novel AhR moderate agonists and antagonists using chemical biology approaches. The mechanisms and mode of interactions with AhR by these hits were also revealed using both experimental and computational studies. The newly identified AhR moderate agonists and antagonists were predicted to bind to AhR and modulate AhR signaling. The structure-activity relationships of moderate agonists and antagonists and their unique binding features with AhR have created a solid framework for further optimization of the next generation of AhR modulators.

Overexpression of microRNA-216a inhibits autophagy by targeting regulated MAP1S in colorectal cancer.

Background: Autophagy executes the rapid degradation of unneeded proteins and organelles through the lysosomal pathway, and is a crucial catabolic process widely conserved among eukaryotes. miRNAs can modulate autophagy by targeting genes encoding proteins involved in the process. A great deal of researchhas indicated that miR-216a was a functional miRNA related to tumorigenesis. However, the contribution of miR-216a to autophagy in colorectal cancer (CRC) remains unclear. The purpose of this study was to investigate the role of miR-216a in autophagy in CRC cells. Methods: The expression levels of miR-216a in 67 paired CRC patients were evaluated by qRT-PCR. Direct gene targeting predicted by TargetScan and miRanda was confirmed by luciferase activity. Western blot and flow cytometry were used to identify the regulatory mechanism of miR-216a on autophagy in CRC cells. Results: We determined that miR-216a is downregulated in CRC by screening its expression in 67 CRC tissue samples. Dual luciferase reporter assays showed that miR-216a binds the 3'-UTR of MAP1S, suggesting that MAP1S is a direct target of miR-216a. miR-216a could inhibit autophagy in HCT-116 and HT-29 CRC cells through downregulating MAP1S expression. Flow cytometry and Western blot analysis demonstrated that overexpression of miR-216a reduced MAP1S mRNA and protein levels. Moreover, we determined that miR-216a-regulated inhibition of autophagy via MAP1S regulation involves the TGF-ß pathway. Conclusion: Taken together, our findings indicate that miR-216a was a tumor-suppressor miRNA in human CRC, which can inhibit autophagy via the TGF-ß/MAP1S pathway.

Transcriptomic analysis of Anabas testudineus and its defensive mechanisms in response to persistent organic pollutants exposure.

The freshwater climbing perch (Anabas testudineus) can tolerate water environments contaminated with persistent organic pollutants (POPs). The mechanisms underlying this tolerance are unknown. We used de novo transcriptomic analysis to investigate the defensive mechanisms of A. testudineus against POPs based on its genetic features and biological responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure. Our results revealed a specific expansion of cytochrome P450 (CYP) 3A subfamily, which may be involved in the elimination of certain POPs. In xenobiotic responses, the aryl-hydrocarbon receptor (AhR) pathway represents a critical signaling mechanism, and we characterized four AhR and two AhR nuclear translocator homologs and one AhR repressor (AhRR) gene in A. testudineus. TCDD-induced AhRR and CYP1A mRNA upregulation suggests that negative-feedback regulation of AhR signaling through AhRR helps avoid excessive xenobiotic responses. Furthermore, liver and gill transcriptomic profiles were markedly altered after TCDD exposure, with some of the altered genes being related to common defensive responses reported in other species. Based on the newly identified TCDD-altered genes, several A. testudineus-specific responses are proposed, such as enhanced fatty acid ß-oxidation. The genetic features of CYP3A subfamily and AhR pathway and the TCDD-induced defensive biological processes elucidated here enhance our understanding of A. testudineus defensive responses against POPs.

Metabolic profiling study on potential toxicity in male mice treated with Dechlorane 602 using UHPLC-ESI-IT-TOF-MS.

Dechlorane 602 (Dec 602), a chlorinated flame retardant, has been widely detected in different environmental matrices and biota. However, toxicity data for Dec 602 seldom have been reported. A metabolomics study based on ultra-high performance liquid chromatography coupled with ion trap time-of-flight mass spectrometry was employed to study the urine and sera metabolic profiles of mice administered with Dec 602 (0, 0.001, 0.1, and 10 mg/kg body weight per day) for 7 days. A significant difference in metabolic profiling was observed between the Dec 602 treated group and the control group by multivariate analysis, which directly reflected the metabolic perturbations caused by Dec 602. The metabolomics analyses of urine from Dec 602-exposed animals exhibited an increase in the levels of thymidine and tryptophan as well as a decrease in the levels of tyrosine, 12,13-dihydroxy-9Z-octadecenoic acid, 2-hydroxyhexadecanoic acid and cuminaldehyde. The metabolomics analyses of sera showed a decrease in the levels of kynurenic acid, daidzein, adenosine, xanthurenic acid and hypoxanthine from Dec 602-exposed animals. These findings indicated Dec 602 induced disturbance in phenylalanine, tyrosine and tryptophan biosynthesis, tryptophan metabolism, tyrosine metabolism, pyrimidine metabolism, purine metabolism, ubiquinone and other terpenoid-quinone biosynthesis; phenylalanine metabolism and aminoacyl-tRNA biosynthesis. Significant alterations of immune and neurotransmitter-related metabolites (tyrosine, tryptophan, kynurenic acid, and xanthurenic acid) suggest that the toxic effects of Dec 602 may contribute to its interactions with the immune and neuronal systems. This study demonstrated that the UHPLC-ESI-IT-TOF-MS-based metabolomic approach can obtain more specific insights into the potential toxic effects of Dec 602 at molecular level.

Development and Application of a Novel Bioassay System for Dioxin Determination and Aryl Hydrocarbon Receptor Activation Evaluation in Ambient-Air Samples.

Airborne persistent toxic substances are associated with health impacts resulting from air pollution, for example, dioxins, dioxin-like polychlorinated biphenyls, and certain polycyclic aromatic hydrocarbons (PAHs), which activate aryl hydrocarbon receptors (AhR) and thereby produce adverse outcomes. Thus, a bioassay for evaluating AhR activation is required for risk assessment of ambient-air samples, and for this purpose, we developed a new and sensitive recombinant mouse hepatoma cell line, CBG2.8D, in which a novel luciferase-reporter plasmid containing two copies of a newly designed dioxin-responsive domain and a minimal promoter derived from a native gene were integrated. The minimal detection limit for 2,3,7,8-tetrachlorodibenzo- p-dioxin with this assay system was 0.1 pM. We used CBG2.8D to determine dioxin levels in 45 ambient-air samples collected in Beijing. The measured bioanalytical equivalent (BEQ) values were closely correlated with the toxic equivalent values obtained from chemical analysis. In haze ambient-air samples, the total activation of aryl hydrocarbon receptors (TAA) was considerably higher than the BEQ of dioxin-rich fractions, according to the results of the cell-based bioassay. Notably, the haze samples contained abundant amounts of PAHs, whose relative toxicity equivalent was correlated with the TAA; this finding suggests that PAHs critically contribute to the AhR-related biological impacts of haze ambient-air samples.