Identification of differentially expressed tumour-related genes regulated by UHRF1-driven DNA methylation.

Ubiquitin-like with PHD and RING finger domains 1 (UHRF1) is an epigenetic regulator that plays critical roles in tumours. However, the DNA methylation alteration patterns driven by UHRF1 and the related differentially expressed tumour-related genes remain unclear. In this study, a UHRF1-shRNA MCF-7 cell line was constructed, and whole-genome bisulfite sequencing and RNA sequencing were performed. The DNA methylation alteration landscape was elucidated, and DNA methylation-altered regions (DMRs) were found to be distributed in both gene bodies and adjacent regions. The DMRs were annotated and categorized into 488 hypermethylated/1696 hypomethylated promoters and 1149 hypermethylated/5501 hypomethylated gene bodies. Through an integrated analysis with the RNA sequencing data, 217 methylation-regulated upregulated genes and 288 downregulated genes were identified, and these genes were primarily enriched in nervous system development and cancer signalling pathways. Further analysis revealed 21 downregulated oncogenes and 15 upregulated TSGs. We also showed that UHRF1 silencing inhibited cell proliferation and migration and suppressed tumour growth in vivo. Our study suggested that UHRF1 and the oncogenes or TSGs it regulates might serve as biomarkers and targets for breast cancer treatment.

The competitive advantage of Microcystis aeruginosa over Scenedesmus obliquus weakened by exposure to polylactic acid microplastics.

Aquatic ecosystems are heavily affected by microplastics (MPs), and its impacts on aquatic life have received extensive attention. However, it is still unclear how biodegradable MPs influence the growth and competition of phytoplankton. In this study, the response of growth dynamics, alternation in algal cell morphology and toxin-producing capability, and changes in the extracellular process of Microcystis aeruginosa (M. aeruginosa) and Scenedesmus obliquus (S. obliquus) were systematically studied in monoculture and co-culture conditions with and without the presence of polylactic acid MPs (PLA-MPs). The results indicated that although the loss of cell integrity was observed, PLA-MPs addition (50 mg/L) caused a 1.40- and 1.36-fold increase in cell densities of M. aeruginosa and S. obliquus in monoculture systems, respectively. This suggests the PLA-MPs more favored the growth of M. aeruginosa. This effect was manifested in co-culture conditions, because the degradation of PLA-MPs provided additional inorganic carbon in the experimental systems and benefited the growth of both M. aeruginosa and S. obliquus. Meanwhile, the synthesis of microcystins from the toxic M. aeruginosa was substantially reduced upon PLA-MPs exposure, which reduced the competitive advantage of M. aeruginosa over S. obliquus. Thus; the cell density of M. aeruginosa and S. obliquus showed 1.15- and 1.88-folds increasing compared to that without PLA-MPs addition. This interaction between PLA-MPs and algae weakened the competitive advantage of M. aeruginosa over S. obliquus, but their competitive outcomes remained unchanged. The results provided new insights into understanding the potential ecological risks of biodegradable plastics in aquatic ecosystems.

Microcystins-Loaded Aged Nanoplastics Provoke a Metabolic Shift in Human Liver Cells.

Studies concerning the toxicity of pollutant-loaded nanoplastics (NPs) toward humans are still in their infancy. Here, we evaluated the adsorption of microcystins (MCs) by pristine and aged polystyrene nanoplastics (PSNPs), prepared MCs-loaded aged PSNPS (1, 5, 10, 15, and 19 µg/mg), and systematically mapped the key molecular changes induced by aged and MCs-loaded PSNPs to human hepatoblastoma (HepG2) cells. According to the results, MC-LR adsorption is increased 2.64-fold by aging, and PSNP accumulation is detected in HepG2 cells. The cytotoxicity of the MC-LR-loaded aged PSNPs showed a positive relationship with the MC-LR amount, as the cell viability in the 19 µg/mg loading treatment (aPS-MC19) was 10.84% lower than aged PSNPs; meanwhile, more severe oxidative damage was observed. Primary approaches involved stressing the endoplasmic reticulum and reducing protein synthesis that the aged PSNPs posed for HepG2 cells, while the aggravated cytotoxicity in aPS-MC19 treatment was a combined result of the metabolic energy disorder, oxidative damage, endoplasmic reticulum stress, and downregulation of the MC-LR target protein. Our results confirm that the aged PSNPs could bring more MC-LR into the HepG2 cells, significantly interfere with biological processes, and provide new insight into deciphering the risk of NPs to humans.

Controlling internal nutrients loading at low temperature using oxygen-loading zeolite and submerged macrophytes enhances environmental resilience to subsequent high temperature.

Nutrients releasing from anoxic sediment can be enhanced in summer because the dissolved oxygen (DO) consumption, nitrogen (N) and phosphorus (P) migration are susceptible to temperature. Herein, we proposed a method to hinder the aquatic environmental deterioration in warm seasons through consecutive application of oxygen- and lanthanum-modified zeolite (LOZ) and submerged macrophytes (V. natans) at low temperature scenario (5 °C, with depleted DO in water), and the effect was examined with drastic increasing the ambient temperature to 30 °C. The investigation was conducted in a microcosm scale including sediment cores (with a diameter of 11 cm, height of 10 cm) and overlying water (with depth of 35 cm). During the 60 days experiment, application of LOZ at 5 °C facilitated slower releasing and diffusion of oxygen from LOZ and the growth of V. natans. Thereby, when the temperature was increased to 30 °C and maintained for 35 days, the DO reached 10.01 mg/L, and the release of P and N from the sediment was reduced by 86% and 92%, respectively. This was achieved from the joint efforts of adsorption, biological conversion, chemical inactivation, and assimilation. Also, the LOZ inhibited 80% N2O, 75% CH4, and 70% CO2 emissions primary by promoting V. natans growth and reshaping microbiota. Meanwhile, the colonization of V. natans benefited the sustainable improvement in the water quality. Our results addressed the time that the remediation of anoxic sediment can be applied.

The Inhibition of Microcystin Adsorption by Microplastics in the Presence of Algal Organic Matters.

Microplastics (MPs) could act as vectors of synthetic chemicals; however, their influence on the adsorption of chemicals of natural origin (for example, MC-LR and intracellular organic matter (IOM), which could be concomitantly released by toxic Microcystis in water) is less understood. Here, we explored the adsorption of MC-LR by polyethylene (PE), polystyrene (PS), and polymethyl methacrylate (PMMA). The results showed that the MPs could adsorb both MC-LR and IOM, with the adsorption capability uniformly following the order of PS, PE, and PMMA. However, in the presence of IOM, the adsorption of MC-LR by PE, PS, and PMMA was reduced by 22.3%, 22.7% and 5.4%, respectively. This is because the benzene structure and the specific surface area of PS facilitate the adsorption of MC-LR and IOM, while the formation of Π-Π bonds favor its interaction with IOM. Consequently, the competition for binding sites between MC-LR and IOM hindered MC-LR adsorption. The C=O in PMMA benefits its conjunction with hydroxyl and carboxyl in the IOM through hydrogen bonding; thus, the adsorption of MC-LR is also inhibited. These findings highlight that the adsorption of chemicals of natural origin by MPs is likely overestimated in the presence of metabolites from the same biota.

Microplastics benefit bacteria colonization and induce microcystin degradation.

Microplastics (MPs) can sorb toxic substances and be colonized by microorganisms. However, the interactions between the adsorbed toxic substances and the MPs biofilm remains inadequately understood. Here, a 37-days microcosm experiment was conducted to investigate the influence of polystyrene microplastics (PS-MPs) on microcystin (MC-LR) behavior in turbulent scenarios. The results revealed that adsorption by PS-MPs was the primary process that led to a quick reduction of aquatic MC-LR concentrations. With the colonization of microorganisms on the PS-MPs, the attached biofilm altered the surface properties of PS-MPs, which enhanced the bio-adsorption of MC-LR. Meanwhile, microcystins degrading bacteria, such as Sphingomonadaceae and Methylophilaceae, inhabited in the biofilm, which facilitated the MC-LR biodegradation; this was also demonstrated by the identified MC-LR degradation products. Thus, the MC-LR concentration in water was constantly decreased, with a maximum removal capability of 35.8% in PS-MPs added groups. In addition, a 25% reduction of MC-LR was recorded in PS-MPs added static water. This suggested that the interaction between PS-MPs, biofilm, and MC-LR may be prevalent in natural waters. Our results indicate MPs as vectors for toxic substances could be a double-edged sword (adsorption and biodegradation), which provides new insights for understanding the ecological risks of microplastics.

Potassium supplement enhanced cadmium removal in a Microcystis aeruginosa photobioreactor: Evidence from actual and simulated wastewater.

In this study, a Microcystis aeruginosa-based photobioreactor (M. aeruginosa-based PBR) was developed for the removal of cadmium (Cd2+) from diluted actual mine wastewater (DW) and Cd2+-contained simulated wastewater (SW), with a uniform Cd2+ concentration of 0.5 mg/L. For the DW and SW, both K+ -abundant (DWA & SWA) and K+-insufficient (DWB & SWB) treatments were conducted. It was found that continuous supplementation of K+ benefited Cd2+ removal. The Cd2+ removal efficiency in SWA reached 70% during the 41 days of operation, which was 20% higher than that in the SWB. The K+ addition triggered great higher Cd2+ removal efficiency (90%) in the DWA in comparison to the SWA. The Cd2+ assimilation by M. aeruginosa and Cd2+ retention on M. aeruginosa surface were the primary processes involved in the PBR system. The K+ starvation triggered a 45% and 43% loss of M. aeruginosa biomass in the DWA and the DWB, respectively. Hence, the Cd2+ removal efficiency in DWB increased significantly, and this was attributed to the increased abundance of non-living cells and enhanced bioretention of Cd2+. The results revealed that continuous K+ supplementation enhanced the Cd2+ removal efficiency in the M. aeruginosa-based PBR jointly by prompting algal cell growth, Cd2+ assimilation and biosorption, as well as Cd2+ retention on the algal cells.

Demethylation drug 5-Aza-2'-deoxycytidine-induced upregulation of miR-200c inhibits the migration, invasion and epithelial-mesenchymal transition of clear cell renal cell carcinoma in vitro.

[This retracts the article DOI: 10.3892/ol.2016.4364.].

Potassium regulates cadmium toxicity in Microcystis aeruginosa.

Microcystis aeruginosa (M. aeruginosa) was found to be capable of cadmium (Cd2+) assimilation. Potassium (K+), an essential factor in transmembrane transport, can possibly manipulate the interaction between Cd2+ and M. aeruginosa. In this study, the effect of available K+ levels on Cd2+ toxicity in M. aeruginosa is examined. The results showed that the K+ level was positively linked with toxicity of Cd2+ to M. aeruginosa. And with respect to the M. aeruginosa incubated in K+ = 460 µM treatment, the release of extracellular polymeric substance was augmented, which benefited the retention of Cd2+ on the M. aeruginosa surface. In addition, the assimilation of Cd2+ showed a 3.42-fold increase in comparison to that without K+ supplement. Moreover, the enhanced K+ level caused the up-regulation of the Cd2+ transporting protein and down-regulation of the Cd2+ efflux protein, associated with the positive energy metabolism response. These results documented that the K+ availability could influence the toxicity of Cd2+ to M. aeruginosa jointly through the manipulation of Cd2+ assimilation, excretion, and the biological response. These findings may attach importance to the effects of K+ level on Cd2+ assimilation by M. aeruginosa and shed a degree of light on the enhanced Cd2+ removal using algal-based technology.

Potassium regulates the growth and toxin biosynthesis of Microcystis aeruginosa.

Potassium (K+) is the most abundant cation in phytoplankton cells, but its impact on Microcystis aeruginosa (M. aeruginosa) has not been fully documented. This study presents evidence of how K+ availability affects the growth, oxidative stress and microcystin (MC) production of M. aeruginosa. The iTRAQ-based proteomic analysis revealed that during K+ deficiency, serious oxidative damage occurred and the photosynthesis-associated and ABC transporter-related proteins in M. aeruginosa were substantially downregulated. In the absence of K+, a 69.26% reduction in cell density was shown, and both the photosynthesis and iron uptake were depressed, which triggered a declined production of ATP and expression of MC synthetases genes (mcyA, B and D), and MC exporters (mcyH). Through the impairment of both the MC biosynthesis and MC transportation out of cells, K+ depletion caused an 85.89% reduction of extracellular MC content at the end of the study. However, with increasing in the available K+ concentrations, photosynthesis efficiency, the expression of ABC-transporter proteins, and the transcription of mcy genes displayed slight differences compared with those in the control group. This work represents evidence that K+ availability can regulate the physiological metabolic activity of M. aeruginosa and K+ deficiency leads to depressed growth and MC production in M. aeruginosa.

Aquatic toxicity of heavy metal-containing wastewater effluent treated using vertical flow constructed wetlands.

The effluent from municipal wastewater can be discharged into the surface water once the chemical parameters meet the standard requirements. However, little attention has been paid to assess the toxicity of the effluent in the receiving water. In this study, vertical flow constructed wetlands (VFCWs) were used to treat the heavy metal-containing wastewater. In addition, the toxicity of the effluent towards Chlorella pyrenoidosa and Daphnia magna was evaluated. The results showed that the VFCWs removed nearly 80% of the total nitrogen, nitrate, and Cd2+ from the wastewater during a 60 day operation. Acute toxicity assessments demonstrated that incubating the plankton in 10% (v/v) effluent enhanced their growth, but a further increase in the effluent proportion (50% and 100%) exhibited detrimental effects towards the aquatic organisms. The superoxide dismutase (SOD) and peroxidase (POD) activities in C. pyrenoidosa and D. magna peaked but then decreased with the increasing effluent proportion, indicating that incubation in a higher proportion of the effluent could damage the anti-oxidative capabilities of the organisms, which aligned with the enhanced reactive oxygen species (ROS) levels and malondialdehyde (MDA) contents. After 96 h of incubation, the assimilation of Cd2+ was most obvious in all the studied effluent gradients in comparison to Cu2+ and Pb2+. Additionally, the correlation analysis between the plankton growth and heavy metal removal revealed that Cd2+ removal clearly benefited the growth of C. pyrenoidosa and D. magna. These results suggest that additional endeavor should be made on the heavy metal removal, to reduce the potential ecological risk of the final discharge.

Strong turbulence benefits toxic and colonial cyanobacteria in water: A potential way of climate change impact on the expansion of Harmful Algal Blooms.

Extreme natural events such as typhoons can amplify the effect of hydrodynamics on the lake ecosystems. Here we presented data on the effect of typhoons on algal cell size based on field observation. Then turbulence simulation systems were used to decipher the response of natural phytoplankton communities to a range of turbulence regimes (linked to typhoon-induced turbulence intensity) under laboratory conditions. Turbulence intensities of 6.17 × 10-3, 1.10 × 10-2 and 1.80 × 10-2 m2/s3 benefited algal growth and triggered abrupt switches from unicellular Chlorella dominated to colonial Microcystis dominance, and the abundance of colonial algae depended on the turbulence intensity. Under the influence of elevated turbulence, Microcystis dominated biomass increased by 2.60-6.58 times compared with that of Chlorella. At a given phytoplankton density and community composition, we observed a significant increase in extracellular microcystins (MCs) and a 47.5-fold increase in intracellular MCs with intensified turbulent mixing, suggesting that the damage of algal cells concomitantly the stimulation of toxin-producing Microcystis. Our results confirmed that the formation of large colonial algal cells, enhancement of the succession of algal species, and most importantly, the induction of toxin-producing Microcystis, were the active adaption strategy when phytoplankton were impacted by strong turbulence. The result implies that the ongoing climates changes and typhoon events are likely to contribute to undesirable outcomes concerning phytoplankton populations.

Demethylation drug 5-Aza-2'-deoxycytidine-induced upregulation of miR-200c inhibits the migration, invasion and epithelial-mesenchymal transition of clear cell renal cell carcinoma in vitro.

The microRNA (miR)-200 family has been found to be involved in the process of mesenchymal-epithelial transition during renal development. Deregulation of miR-200c has been suggested to be involved in clear cell renal cell carcinoma (ccRCC). However, the precise role of miR-200c in the regulation of ccRCC metastasis has not been previously reported. In the present study, it was observed that miR-200c was frequently downregulated in ccRCC tissue compared with matched adjacent normal tissue. The expression of miR-200c was additionally reduced in ccRCC cell lines when compared with levels in normal renal cells. The DNA demethylation drug 5-Aza-2'-deoxycytidine (Aza) was used to treat several ccRCC cell lines, and it was observed that the expression of miR-200c was significantly increased following Aza treatment. Furthermore, treatment with Aza markedly inhibited ccRCC cell invasion and migration, while treatment with miR-200c inhibitor significantly enhanced invasion and migration of ccRCC cells. In addition, Aza treatment significantly promoted expression of E-cadherin and inhibited the expression of N-cadherin, while the inhibition of miR-200c downregulated E-cadherin and upregulated the expression of N-cadherin, suggesting that miR-200c has a suppressive role in epithelial-mesenchymal transition (EMT) of ccRCC cells. In conclusion, it was suggested that demethylation drug Aza-induced upregulation of miR-200c may inhibit migration, invasion and EMT in ccRCC cells.

Dispersive liquid-liquid microextraction method based on solidification of floating organic droplet for the determination of thiamphenicol and florfenicol in environmental water samples.

Dispersive liquid-liquid microextraction with solidification of a floating organic droplet (DLLME-SFO) followed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection was applied for the determination of thiamphenicol (TAP), florfenicol (FF) in water samples. 1-Undecanol was used as the extraction solvent which has lower density than water, low toxicity, and low melting point (19°C). A mixture of 800mL acetone (disperser solvent) and 80µL of 1-undecanol (extraction solvent) was injected into 20mL of aqueous solution. After 5min, 0.6g of NaCl was added and the sample vial was shaken. After 5min, the sample was centrifuged at 3500rpm for 3min, and then placed in an ice bath. When the extraction solvent floating on the aqueous solution had solidified, it was transferred into another conical vial where it was melted quickly at room temperature, and was diluted with methanol to 1mL, and analyzed by HPLC-UV detection. Parameters influencing the extraction efficiency were thoroughly examined and optimized. The extraction recoveries (ER) and the enrichment factors (EF) ranged from 67% to 72% and 223 to 241, respectively. The limits of detection (LODs) (S/N=3) were 0.33 and 0.56µgL(-1) for TAP and FF, respectively. Linear dynamic range (LDR) was in the range of 1.0-550µgL(-1) for TAP and 1.5-700µgL(-1) for FF, the relative standard deviations (RSDs) were in the range of 2.6-3.5% and the recoveries of spiked samples ranged from 94% to 106%.