[Persistent Inhibition of Ammonium Released from Contaminated Sediments Through a Modified Zeolite and Biofilm System Enhanced by Signaling Molecules].

This experiment used a modified zeolite and biofilm system to find a long-term effective way of repairing sediment. Four types of modified zeolites[AlCl3, Al(NO3)3, Al2(SO4)3, and KAl(SO4)2] and a biofilm system were investigated for the removal of ammonia nitrogen from overlaying water. The results showed that, of the modified zeolites, AlCl3 had the greatest effect on the zeolite and biofilm system, and the optimal modified concentration was 0.8 mol·L-1. The persistence was further studied after adding OHHL, including the inhibition of ammonium released from contaminated sediment by the AlCl3-modified zeolite and biofilm system, NaCl-modified zeolite and biofilm system, and natural zeolite and biofilm system. The results illuminated that the number of bacteria attached to the AlCl3-modified zeolite and biofilm system was the highest, and the proportion of denitrifying bacteria was also high (the initial proportion was 82.1%; 30 days later it was 61.1%). Therefore, the biological regeneration was high (64.9%), which caused the zeolite service life to be up to 8.5 months. Thus, ammonium released from contaminated sediment can be inhibited effectively and continuously by an AlCl3-modified zeolite and biofilm system.

[Effect of Artificial Mixing on Temporal and Spatial Succession of Algae Community Structure in Jinpen Reservoir].

To explore the effect mechanism of the artificial mixing process on the temporal and spatial succession of algae community structure in a water body, this study used water-lifting aerators to induce in-situ artificial mixing of the water body of Jinpen Reservoir, and in-situ spot physical-chemical parameters and algae of the water body of the reservoir were observed during an artificial mixing process. A total of 51 species of 28 genera of 6 families of algae were identified in the water body of the Jinpen Reservoir. The artificial mixing effect of the water-lifting aerators significantly inhibited the growth of algae in the water, and had a significant impact on the community structure. Before activation of the water-lifting aerators, algae were mainly distributed in the surface water body, and Chlorella vulgaris was the dominant species. With the operation of the water-lifting aerators, the algal density of surface water body decreased significantly, and the vertical distribution of the algae density in the water body tended to be uniform. The dominant species tended to succeed in Cyclotella sp. This study used the method of redundancy analysis, combined with critical depth theory and the characteristics of algae growth, to analyze the relationship between the spatial-temporal succession of algae community structure and the changes in the main physical-chemical parameters in Jinpen Reservoir during the artificial process. The analysis results showed that the artificial mixing of the water-lifting aerators mainly affects the temporal and spatial succession of the algae community structure by rapidly destroying the thermal stratification stability of the water body and significantly increasing the water mixing depth.

[Improving Bioremediation of Crude Oil-contaminated Soil by Mild Pre-oxidation].

To obtain a mild Fenton pre-oxidation method, which could promote the efficient degradation of total petroleum hydrocarbons (TPH) in subsequent bioremediation, the differences in the characteristics of the hydroxyl radical (·OH), nutrient consumption, activity of indigenous bacteria (CO2), and TPH removal were investigated during subsequent bioremediation after different Fenton pre-oxidation treatments. The results showed that high biodegradation of TPH was observed after mild Fenton pre-oxidation (·OH existence time:73 h; H2O2 concentration:225 mmol·L-1), because of the high activity of residual bacteria. Moreover, the same TPH removal with the addition of bacteria could be achieved without adding bacteria (the TPH removal rate 38%) because the activity of the residual bacteria was strong after mild Fenton pre-oxidation. Under the condition of no additional bacteria source, mild Fenton pre-oxidation TPH removal (approximately 38%) was higher than that after ordinary Fenton pre-oxidation (15.32%-33.15%). Further analysis of the removal efficiency of each chain of hydrocarbons revealed that the mild pre-oxidation group could reduce the inhibition of the chain hydrocarbon components (C17-C21) in the subsequent bioremediation stage. Comparing the activity of the indigenous bacteria in each group, revealed that mild pre-oxidation could appropriately stimulate the growth and increase the activity of indigenous microorganisms, all of which are beneficial to the removal of TPH.

[Sources and Distribution of Phosphorus in Sediments of the Jinpen Reservoir].

In order to explore the sources and distribution of phosphorus in sediments of a stratified water source reservoir, the total phosphorus (TP) content and distribution of phosphorus fractions in sedimentation particles and sediments of the Jinpen Reservoir of Xi'an were analyzed from March to November in 2017. The results showed that the TP content in the surface sediments of the Jinpen Reservoir was obviously affected by the deposition of particulate phosphorus (PP), and the correlation coefficient was 0.8775. Besides, this TP pool was also affected by the biogeochemistry of sediments. From June to August, algae in the Jinpen Reservoir propagated intensely, and a large number of dead algae were deposited on the bottom of the water body, which resulted in a type of endogenous pollution dominated by algae. The concentration of PP reached (753.51±17.11) mg·kg-1, and the content of TP increased, with NaOH-nrP as the main component. During the flood season of the Jinpen Reservoir from September to November, the runoff water carried a large amount of sediments with large pollutant loads, which resulted in increases of the concentration of PP in the water body. However, the TP content in the sediment per unit mass was relatively small. As a result, the TP content of surface sediments decreased, with inorganic Ca-P and rest-P as the main forms, which accounted for 55.8%-66.2% of the TP in sediment, and were influenced by particle sedimentation. The SRP, BD-P, and NaOH-srP, the most active fractions, underwent a series of transport and transformation processes under the changing environmental conditions (mainly redox conditions), and these forms were obviously affected by the biochemical processes in sediments and minimally affected by the sedimentation processes of the reservoir.

[Effect of Signal Molecule Combined with Thiobacillus denitrificans on Simultaneous Removal of Nitrogen and Sulfur].

The effects of Thiobacillus denitrificans combined with signal molecules on the removal of sulfide and nitrate was investigated. By adding signal molecules and T. denitrificans at the same, the total number of microorganisms increased, the removal of sulfide and nitrate was accelerated, and an increase in nitrogen gas and more stable accumulation of elemental sulfur was observed. The total number of microorganisms after the reaction was detected using fluorescence in situ hybridization (FISH) technique. In this experiment, the optimal concentration for the stable accumulation of elemental sulfur from six concentrations of signal molecules was revealed. Further, the effects of adding signal molecules, T. denitrificans, and their combination were analyzed at this concentration. The results showed that it was easier to accumulate elemental sulfur after the addition of 1.0 µmol·L-1 signal molecule. After adding both T. denitrificans and 1.0 µmol·L-1 signal molecules at a sulfide concentration of 200 mg·L-1, the removal of sulfide and nitrate increased to 99.8% and 96.9% at 72 h, respectively, and increases in nitrogen gas and sulfur were observed. The amounts of elemental sulfur and nitrogen gas reached to 59.0 mg and 80.0 mL, respectively, after adding 2.5 µmol·L-1 signal molecules at 72 h when the sulfide concentration was 300 mg·L-1. Under those conditions, the removal efficiency of sulfide and nitrate reached 99.0% and 93.9%, and the production of elemental sulfur and nitrogen reached 63.1 mg and 79.5 mL, respectively.

SND p102 promotes extracellular matrix accumulation and cell proliferation in rat glomerular mesangial cells via the AT1R/ERK/Smad3 pathway.

SND p102 was first described as a transcriptional co-activator, and subsequently determined to be a co-regulator of Pim-1, STAT6 and STAT5. We previously reported that SND p102 expression was increased in high glucose-treated mesangial cells (MCs) and plays a role in the extracellular matrix (ECM) accumulation of MCs by regulating the activation of RAS. In this study, we further examined the roles of SND p102 in diabetic nephropathy (DN)-induced glomerulosclerosis. Rats were injected with STZ (50 mg/kg, ip) to induce diabetes. MCs or isolated glomeruli were cultured in normal glucose (NG, 5.5 mmol/L)- or high glucose (HG, 25 mmol/L)-containing DMEM. We found that SND p102 expression was significantly increased in the diabetic kidneys, as well as in HG-treated isolated glomeruli and MCs. In addition, HG treatment induced significant fibrotic changes in MCs evidenced by enhanced protein expression of TGF-ß, fbronectin and collagen IV, and significantly increased the proliferation of MCs. We further revealed that overexpression of SND p102 significantly increased the protein expression of angiotensin II (Ang II) type 1 receptor (AT1R) in MCs by increasing its mRNA levels via directly targeting the AT1R 3'-UTR, which resulted in activation of the ERK/Smad3 signaling and subsequently promoted the up-regulation of fbronectin, collagen IV, and TGF-ß in MCs, as well as the cell proliferation. These results demonstrate that SND p102 is a key regulator of AT1R-mediating ECM synthesis and cell proliferation in MCs. Thus, small molecule inhibitors of SND p102 may be a novel therapeutic strategy for DN.

N-acetylcysteine alleviates angiotensin II-mediated renal fibrosis in mouse obstructed kidneys.

AIM: To investigate the effects of ROS scavenger N-acetylcysteine (NAC) on angiotensin II (Ang II)-mediated renal fibrosis in vivo and in vitro. METHODS: Mice were subjected to unilateral ureteral obstruction (UUO), and then treated with vehicle or NAC (250 mg/kg, ip) for 7 days. Histological changes of the obstructed kidneys were observed with Masson's trichrome staining. ROS levels were detected with DHE staining. The expression of relevant proteins in the obstructed kidneys was assessed using Western blotting assays. Cultured rat renal fibroblast NRK-49F cells were used for in vitro experiments. RESULTS: In the obstructed kidneys, Ang II levels were significantly elevated, and collagen I was accumulated in the interstitial spaces. Furthermore, ROS production and the expression of p47 (a key subunit of NADPH oxidase complexes) were increased in a time-dependent manner; the expression of fibronectin, α-SMA and TGF-ß were upregulated. Administration of NAC significantly alleviated the fibrotic responses in the obstructed kidneys. In cultured NRK-49F cells, treatment with Ang II (0.001-10 µmol/L) increased the expression of fibronectin, collagen I, α-SMA and TGF-ß in dose-dependent and time-dependent manners. Ang II also increased ROS production and the phosphorylation of Smad3. Pretreatment with NAC (5 µmol/L) blocked Ang II-induced oxidative stress and ECM production in the cells. CONCLUSION: In mouse obstructed kidneys, the fibrotic responses result from Ang II upregulation can be alleviated by the ROS scavenger N-acetylcysteine.

Insulin deficiency induces rat renal mesangial cell dysfunction via activation of IGF-1/IGF-1R pathway.

AIM: Diabetic nephropathy is one of the major complications of diabetes and the major cause of end-stage renal disease. In this study we investigated the insulin deficiency (ID) induced changes in renal mesangial cells (MCs) and in the kidney of STZ-induced diabetic rats. METHODS: Cultured rat renal MCs were incubated in ID media. Cell proliferation was analyzed using BrdU incorporation assay. The expression of insulin receptor (IR), insulin-like growth factor-1 receptor (IGF-1R), phosphorylated IGF-1R, fibronectin, and collagen IV was determined with Western blot analysis. STZ-induced diabetic rats were treated with an IGF-1R antagonist picropodophyllin (PPP, 20 mg·kg(-1)·d(-1), po) for 8 weeks. After the rats were euthanized, plasma and kidneys were collected. IGF-1 levels in renal cortex were measured with RT-PCR or ELISA. The morphological changes in the kidneys were also examined. RESULTS: Incubation in ID media significantly increased cell proliferation, the synthesis of fibronectin and collagen IV, and the expression of IGF-1 and IGF-1R and phosphorylated IGF-1R in renal MCs. Pretreatment of the cells with PPP (50 nmol/L) blocked ID-induced increases in cell proliferation and the synthesis of fibronectin and collagen IV; knockdown of IGF-1R showed a similar effect as PPP did. In contrast, treatment of the cells with IGF-1 (50 ng/mL) exacerbated ID-induced increases in cell proliferation. In the kidneys of diabetic rats, the expression of IGF-1, IGF-1R and phosphorylated IGF-1R were significantly elevated. Treatment of diabetic rats with PPP did not lower the blood glucose levels, but significantly suppressed the expression of TGF-ß, fibronectin and collagen IV in the kidneys, the plasma levels of urinary nitrogen and creatinine, and the urinary protein excretion. CONCLUSION: Insulin deficiency increases the expression of IGF-1 and IGF-1R in renal MCs and the kidney of diabetic rats, which contributes to the development of diabetic nephropathy.

Vertical Distribution of Bacterial Community Diversity and Water Quality during the Reservoir Thermal Stratification.

Reservoir thermal stratification drives the water temperature and dissolved oxygen gradient, however, the characteristic of vertical water microbial community during thermal stratification is so far poorly understood. In this work, water bacterial community diversity was determined using the Illumina Miseq sequencing technique. The results showed that epilimnion, metalimnion and hypolimnion were formed steadily in the JINPEN drinking water reservoir. Water temperature decreased steadily from the surface (23.11 °C) to the bottom (9.17 °C). Total nitrogen ranged from 1.07 to 2.06 mg/L and nitrate nitrogen ranged from 0.8 to 1.84 mg/L. The dissolved oxygen concentration decreased sharply below 50 m, and reached zero at 65 m. The Miseq sequencing revealed a total of 4127 operational taxonomic units (OTUs) with 97% similarity, which were affiliated with 15 phyla including Acidobacteria, Actinobacteria, Armatimonadetes, Bacteroidetes, Caldiserica, Chlamydiae, Chlorobi, Chloroflexi, Cyanobacteria, Firmicutes, Gemmatimonadetes, Nitrospirae, Planctomycetes, Proteobacteria, and Verrucomicrobia. The highest Shannon diversity was 4.41 in 45 m, and the highest Chao 1 diversity was 506 in 5 m. Rhodobacter dominated in 55 m (23.24%) and 65 m (12.58%). Prosthecobacter dominated from 0.5 to 50 m. The heat map profile and redundancy analysis (RDA) indicated significant difference in vertical water bacterial community composition in the reservoir. Meanwhile, water quality properties including dissolved oxygen, conductivity, nitrate nitrogen and total nitrogen have a dramatic influence on vertical distribution of bacterial communities.

Oxidative degradation of organic pollutants in aqueous solution using zero valent copper under aerobic atmosphere condition.

Oxidative degradation of organic pollutants and its mechanism were investigated in aqueous solution using zero valent copper (ZVC) under aerobic atmosphere condition. Diethyl phthalate (DEP) was completely oxidized after 120 min reaction by ZVC at initial pH 2.5 open to the air. DEP degradation followed the pseudo-first-order kinetics after the lag period, and the degradation rate of DEP increased gradually with the increase of ZVC dosage, and the decrease of initial pH from 5.8 to 2.0. ZVC required a shorter induction time and exhibited persistent oxidation capacity compared to that of zero valent iron and zero valent aluminium. The mechanism investigation showed that remarkable amount of Cu(+)/Cu(2+) and H2O2 were formed in ZVC acidic system, which was due to the corrosive dissolution of ZVC and the concurrent reduction of oxygen. The addition of tert-butanol completely inhibited the degradation of DEP and the addition of Fe(2+) greatly enhanced the degradation rate, which demonstrated that hydroxyl radical was mainly responsible for the degradation of DEP in ZVC acidic system under aerobic atmosphere condition, and the formation of hydroxyl radical was attributed to the Fenton-like reaction of in situ formed Cu(+) with H2O2.

[Characteristic of autotrophic denitrification in bioaugmented anaerobic system].

An autotrophic denitrification process using reduced sulfide as electron donor in anaerobic system is proposed as an efficient and cost effective alternative to conventional heterotrophic denitrification for low C/N ratio wastewaters and for simultaneous removal of sulfide and nitrate. A suspended culture of Thiobacillus denitrificans bacteria was fast and efficiently established in anaerobic system. 5 series bioaugmented anaerobic systems with different N/S ratio synthetic influent were set up. Sulfide, nitrate, sulfate, and nitrite concentration in the effluent at every 3 hours were measured after 15 day. The primary objective was to investigate the characteristic of autotrophic denitrification and sulfide oxidation, and to reveal the mechanism of autotrophic denitrification process using reduced sulfide as electron donor in bioaugmented anaerobic system. 90% removal efficiency of sulfide was observed after 3 hours and removal efficiency of sulfide had no reference to N/S ratio. The rate of sulfide oxidation was 20-24 g x (m3 x h)(-1), which was 10 times higher than that have been reported in the literatures. Maximum removal efficiency of nitrate was 65% after 6 hours, which enhanced with increasing N/S ration of influent. The result showed bacteria reduced nitrate to nitrite at first step, and resulted in accumulation of nitrite to 93 mg x L(-1) to the large extent. Accumulated nitrite was disappear on low influent N/S ratio condition after 6 hours, and need 21 hours on high influent N/S ratio condition. So, complete sulfide and nitrate removal was achieved during 6 hours. The results revealed that the sharp decreasing of sulfide concentration attributed to the reaction between sulfide and biosulfur particles to form polysulfide anions. In addition, biosulfur produced in 3 hours was the main source of electron donor for reducing nitrate.

[Bioremediation of petroleum hydrocarbon contaminated soil by bioaugmentation products].

In an experimental investigation of bioaugmentation products affected on the petroleum contaminated soil. The influence of the bioaugmentation products dose, injections and temperature on bioremediation were studied. The results showed that the degradation rate was related positively to the amount of inoculation, when the dose was increased to 0.6 mg x kg(-1), total petroleum hydrocarbon (TPH) degradation rate was 87% in 48 days. The results of GC-MS indicated that the dominant petroleum constituents in oil-contaminated raw soil were 82.1% n-alkane, 16% alkene and little of others hydrocarbons, such as carotane, alkylnaphthalenes, hopanes, and steranes. The peaks amount of GC profile decreased from 32 to 14 after 40 days of bioremediation, this result indicated that branched alkanes, alkene, and alkylnaphthalenes were thoroughly degraded, then line alkanes, hopanes, and steranes were left in soil. In addition, the longer part of n-alkane were degraded with rate relatively higher, while the residual fraction at the end of the test is shorter part of n-alkane because bacteria degraded the longer n-alkane to shorter. The shorter n-alkane concentration decreased with increasing inoculation. One time injection of bioaugmentation products into soil clearly improved the biodegradation efficiency higher than injection of bioaugmentation products in turn. Soil temperature also affected TPH degradation rate when it was 30 degrees C, TPH rate reached 80%, where as when it was 20 degrees C, the TPH rate was lower to 60%, which indicated higher temperature improved TPH degradation and accelerated bioremediation.