Tribulus terrestris L. protects glomerular endothelial cells via the miR155-H2AC6 interaction network in hypertensive renal injury.

BACKGROUND: Hypertensive renal injury is one of the most lethal complications of hypertension. At present, renin-angiotensin-aldosterone system (RAAS) blockers are considered the best drugs for the treatment of renal injury in hypertension because of their nephroprotective effect of reducing proteinuria, but there are no specific drugs for this purpose, however, clinical trials proved that Chinese medicine has a protective effect on target organs in the treatment of hypertension. Tribulus terrestris L. (TrT), a traditional Chinese medicine (TCM), has potential applications due to its reno-protective and immunomodulatory effects. METHODS: We investigated the underlying reno-protective mechanism of TrT on Angiotensin II (AngII)-induced hypertensive renal injury in glomerular endothelial cells by integrating the differential expression profiles of micro RNA (miRNA) and messenger RNA (mRNA) to construct a miRNA-mRNA interaction network associated with hypertensive kidney injury, followed by quantitative real-time polymerase chain reaction (qRT-PCR) for validation. RESULTS: Seventy-six differentially expressed mRNAs (DEmRNAs) and 1 differentially expressed miRNAs (DEmiRNAs) were identified in the control group and the AngII-induced hypertensive renal injury group, respectively. 110 DEmRNAs and 27 DEmiRNAs were identified in the TrT treatment group and the AngII-induced group, respectively. The core component of the miRNA-mRNA network was miR-155-5p. Our study showed that miR-155-5p expression levels were more decreased in the AngII-induced hypertensive renal injury group than the control group. TrT treatment also significantly upregulated miR-155-5p. Additionally, we found that miR-155-5p expression levels were negatively correlated with H2A clustered histone 6 (H2AC6). CONCLUSIONS: The results of this study indicate that TrT has a reno-protective effect on AngII-induced hypertensive renal injury by miR-155-5p, which negatively regulates the expression of H2AC6. Our findings offer a new therapeutic strategy and have identified an effective candidate target for the treatment of hypertensive renal injury in clinical settings.

[Simultaneous Nitrification and Denitrifying Phosphorus Removal in Continuous Flow Reactor with Intermittent Aeration].

A continuous flow reactor (TCFR) with 10 compartments was used to treat domestic sewage. The anaerobic compartments of TCFR were kept at 3. The anoxic compartments of TCFR were reduced from 2 to 0. Therefore, the aerobic compartments of TCFR were increased gradually from 5 to 7. The aerobic compartments were set to continual aeration in Run1 and intermittent aeration from Run2 to Run4. The aeration/non-aeration ratios were 40 min/20 min,40 min/30 min, and 40 min/40 min, respectively. The nitrification liquid reflux ratios were reduced gradually from 150% to 0%. When the average influent concentrations of COD, NH4+-N, TN, and PO43--P were 259.34, 60.26, 64.42, and 6.10 mg·L-1, respectively, the corresponding effluent concentrations were 26.40, 1.03, 5.84, and 0.3 mg·L-1, respectively in Run4. The nitrogen removal amounts increased gradually from 192.30 mg·h-1 in Run1 to 244.00 mg·h-1 in Run4, and the corresponding removal rates increased from 65.40% to 95.30%. The activity of denitrifying phosphorus accumulating organisms (DPAOs) and phosphorus accumulating organisms (PAOs) increased from 36.05% and 38.20% in Run1 to 140.50% and 133.40% in Run4, respectively. Simultaneous nitrification and denitrifying phosphorus removal was achieved in TCFR by adopting intermittent aeration, which provided a reference for the reformation of sewage treatment plants.

[Characteristics of Denitrifying Phosphorus Removal by A2/O-BAF at Low Temperatures].

Low C/N domestic sewage was treated by an A2/O-biological aerated filter (BAF) system at low temperatures (11-14℃). The characteristics of pollutant removal, the ratio of denitrifying phosphorus to nitrogen (ΔPO43-/ΔNO3-N) and effects of aeration flow and effective packing height on nitrification in BAF were studied. The results showed that when the average influent concentrations of COD, NH4+-N, TN and PO43- were 193.1, 58.6, 60.3 and 5.1 mg·L-1 respectively, their effluent concentrations were 46.3, 2.5, 13.4 and 0.3 mg·L-1 respectively, which met the first level A criteria specified in the discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002). The linear fitting of ΔPO43-/ΔNO3--N was between 0.47 and 1.75. The normal distribution of mathematical statistics was applied-and the average standard deviation for ΔPO43-/ΔNO3--N were 1.20 and 0.29 respectively. When the aeration flows were 60 L·h-1 and 100 L·h-1, the effluent concentration of NH4+-N was less than 5.0 mg·L-1, corresponding to the effective packing heights in the BAF of 1.8 m and 1.0 m respectively. However, when the aeration flow was increased to 120 L·h-1, the air-water flow led to biofilm detachment, which caused the effluent concentration of NH4+-N to increase beyond 5.0 mg·L-1.

[Effect of Step Feed on Denitrifying Phosphorus and Nitrate Removal in a Modification of the Two Sludge A2/O-BAF System].

A modification of the two sludge A2/O-BAF system was used to treat low C/N real domestic sewage. In order to improve the utilization of the carbon source, the effects of two step feeds (pre-anoxic zone and anoxic zone) on denitrifying phosphorus and nitrate removal were studied. According to the formula of material balance for COD, the utilization of carbon source was analyzed and evaluated under different ratios of step feed, simultaneously. The results showed that when the ratio of step feed was 7:3 and the influent concentrations of COD, NH4+-N, TN, and TP were 174.99, 58.19, 59.10, and 5.15 mg·L-1, respectively, their effluent concentrations were 29.48, 4.07, 14.10, and 0.40 mg·L-1, and the removal rates were 82.12%, 92.76%, 75.45%, and 91.20%, respectively. It was found that when the ratio of the denitrifying phosphorus accumulation organisms to the phosphorus accumulation organisms(DPAOs/PAOs) was 98.81%, the efficiencies of denitrifying phosphorus and nitrate removal were optimum. By optimizing step feed, the carbon source was utilized effectively, and the efficiencies of nitrogen and phosphorus removal were improved simultaneously. The theoretical basis has thus been provided for the modification of the two sludge A2/O-BAF system to treat low C/N waste water.

[Nitrite Type Denitrifying Phosphorus Removal Capacity of Cycle Activated Sludge Technology Processes Under Different Inducing Patterns].

A modified cyclic activated sludge technology (CAST) reactor was utilized to investigate the phosphorus and nitrogen removal performance under different inducing patterns in this experiment. The results show that nitrite addition under anoxic conditions has a more inhibitory effect on the denitrifying phosphorus removal performance of the sludge. The phosphorus removal performance of the system was least effective when nitrite dosage was 5 mg·L-1. Compared to an anoxic addition system, the CAST system is more stable under aerobic addition conditions. The phosphorus removal properties have a slight fluctuation during each initial operating condition when the nitrite concentrations are 5, 10 and 15 mg·L-1, respectively. However, the phosphorus removal rate was observed to recover quickly and remain stable at more than 95% after acclimatizing for 10, 6, and 34 days, respectively. The effluent phosphorus concentration was less than 0.5 mg·L-1 in all cases. It was also found that the phosphorus removal performance deteriorated drastically when the nitrite dosage was 20 mg·L-1. Nevertheless, the nitrite type denitrifying phosphorus uptake capacity of the sludge was 10.4 times greater than that of the sludge before acclimatizing, suggesting that the phosphorus performance deterioration due to nitrite addition could be relieved and long-term addition is beneficial to enriching denitrifying phosphorus accumulating bacteria using NO2- as an electron acceptor. Moreover, the sludge settling performance was found to be effective and the sludge concentration decreased continuously when adding a certain concentration of nitrite under aerobic conditions, which is of significant for sludge reduction.

[Long-Term Inhibition of FNA on Aerobic Phosphate Uptake and Variation of Phosphorus Uptake Properties of the Sludge].

An alternating anaerobic/oxic ( An/O) sequencing batch reactor (SBR) was employed to investigate the long-term inhibitory effect of free nitrous acid (FNA) on aerobic phosphorus uptake performance and variation of phosphorus uptake properties of the sludge by adding nitrite. The reactor was started up under the condition of 21-23 degrees C. The results showed that FNA had no impact on phosphate release and uptake capacities of the sludge. However, the specific phosphate release/uptake rates was found to be higher. As FNA concentration (measure by HNO2-N) was lower than 0.53 x 10(-3) mg x L(-1), phosphorus removal efficiency of the system was higher than 96.9%. When the FNA concentration was increased to 0.99 x 10(-3) mg x L(-1), 1.46 x 10(-3) mg x L(-1) and 1.94 x 10(-3) mg x L(-1), the phosphorus removal performance deteriorated rapidly. The phosphorus removal efficiency was recovered to 64.42%, 67.33% and 44.14% after 50, 12 and 30 days, respectively, which implied the deterioration of phosphorus removal performance caused by FNA inhibition could be recovered and long-term acclimation could shorten the recovery process. Notably, increasing nitrite consumption appeared during aerobic phase with the concentration of FNA below 1.46 x 10(-3) mg x L(-1). It was also observed that the phosphorus uptake properties of the sludge varied after long-term inhibition. Nitrate and nitrite type anoxic phosphorus uptake capacity was increased by 3.35 and 3.86 times, respectively, suggesting long-term dosing FNA may facilitate the denitrifying of polyphosphate in organisms utilizing nitrite as electron acceptor. Moreover, long-term acclimation favored sludge settling.

[Effect of internal recycle ratio on nitrogen and phosphorus removal characteristics in A2/O-BAF process].

The behaviors of biological phosphorus (P) and nitrogen (N) removal in a lab-scaled anaerobic/anoxic/oxic-biological aerated filter (A2/O-BAF) combined system were investigated during the treatment of real domestic wastewater with the temperature at 15 degrees C, the C/N ratio of 4.9 and internal recycle ratio of 100%, 200%, 300% and 400%. Experimental results clearly showed that COD, N and P can be simultaneously deeply removed in this combined system. When the total HRT was 8.0 h, SRT was 15 d,sludge recycle ratio was 100% and MLSS was 4.0 mg x L(-1), the concentrations of COD, total phosphorus (TP) and ammonia nitrogen could be reached to less than 50.0, 0.5 and 1.0 mg x L(-1) in the effluent, respectively. The concentrations of total nitrogen (TN) could be reduced from 70.9, 72.1, 70.6 and 73.3 mg x L(-1) in the raw wastewater to that of 24.8, 16.5, 9.6 and 8.7 mg x L(-1) in the effluent, respectively. The removal efficiencies of TN were 65.0%, 77.1%, 86.4% and 88.1%, respectively. There was no distinct relationship between the internal recycle ratio and the removal efficiencies of COD, TP and ammonia nitrogen. However, the removal efficiencies of TN increased with the increasing of the internal recycle ratio, the rising rate was descending. Both the capacity of denitrifying and phosphorus removal in anoxic zone increased simultaneously with the increasing of the internal recycle ratio. Batch tests indicated that the population of denitrifying polyphosphate-accumulating organisms (DPAOs) was up to 40.5% of the total phosphate-accumulating organisms (PAOs).