Purification mechanism of microbial metabolism in kitchen-oil wastewater enhanced by cationic vacancies on γ-Al2O3.

The use of catalyst materials to mediate the enhancement of microbial degradation in wastewater is a new economic and energy saving breakthrough in water treatment technology. In this study, γ-Al2O3, which is commonly used as catalyst/carrier, is used as biological filler to treat kitchen-oil wastewater with low biodegradability, and the COD removal rate is about 50 %. It is found that the complexation of cationic vacancies on Al2O3 surface with extracellular polymeric substance (EPS) secreted by microorganisms in wastewater lead to the polarization of electron distribution on biofilm. The efficient degrading bacteria are enriched on reaction interface and obtain electrons to maintain electron dynamic balance by enhancing the transmembrane metabolism of pollutants. The aluminum vacancies on Al2O3 surface accelerate the microbial degradation of pollutants. The cationic vacancies in the structure of catalyst accelerate the acquisition of exogenous electrons by microorganisms without the addition of external energy, which provides a new idea for catalytic fillers to enhance wastewater degradation.

Diversified metabolism makes novel Thauera strain highly competitive in low carbon wastewater treatment.

Thauera, as one of the core members of wastewater biological treatment systems, plays an important role in the process of nitrogen and phosphorus removal from low-carbon source sewage. However, there is a lack of systematic understanding of Thauera's metabolic pathway and genomics. Here we report on the newly isolated Thauera sp. RT1901, which is capable of denitrification using variety carbon sources including aromatic compounds. By comparing the denitrification processes under the conditions of insufficient, adequate and surplus carbon sources, it was found that strain RT1901 could simultaneously use soluble microbial products (SMP) and extracellular polymeric substances (EPS) as electron donors for denitrification. Strain RT1901 was also found to be a denitrifying phosphate accumulating bacterium, able to use nitrate, nitrite, or oxygen as electron acceptors during poly-ß-hydroxybutyrate (PHB) catabolism. The annotated genome was used to reconstruct the complete nitrogen and phosphorus metabolism pathways of RT1901. In the process of denitrifying phosphorus accumulation, glycolysis was the only pathway for glycogen metabolism, and the glyoxylic acid cycle replaced the tricarboxylic acid cycle (TCA) to supplement the reduced energy. In addition, the abundance of conventional phosphorus accumulating bacteria decreased significantly and the removal rates of total nitrogen (TN) and chemical oxygen demand (COD) increased after the addition of RT1901 in the low carbon/nitrogen (C/N) ratio of anaerobic aerobic anoxic-sequencing batch reactor (AOA-SBR). This research indicated that the diverse metabolic capabilities of Thauera made it more competitive than other bacteria in the wastewater treatment system.

[Effects of Dissolved Oxygen on Nutrient Removal Performance and Microbial Community in Low Carbon/Nitrogen Municipal Wastewater Treatment Process].

To explore the effects of dissolved oxygen (DO) on the treatment of low carbon/nitrogen municipal wastewater, this study examined the characteristics of the microbial community in a low carbon source environment. The treatment process was conducted with the aeration area having DO concentrations of 2-3, 1-2, and lower than 1 mg·L-1. The results demonstrated that reduced DO concentration in the aeration area increased the efficiency of the nitrogen removal process by 20.23% and 80.54%, for external and internal carbon sources, respectively. Similarly, the efficiency of internal carbon source utilization in the phosphorus removal process increased by 13.89%, thus enhancing the nutrient removal efficiency of the low carbon/nitrogen wastewater treatment system. High-throughput sequencing and RDA analysis showed that reduced oxygen concentration motivated an adjustment in microbial community structure, causing functional microorganisms (i.e., Dechloromonas) to become dominant. In addition, the upregulation of genes associated with energy production and conversion, signal transduction, substrate transport, and metabolism provided favourable nutritional conditions for the proliferation of functional microorganisms in low carbon source conditions. This study provides a theoretical basis for improving the growth of microorganisms involved in the nutrient removal process when treating low carbon/nitrogen municipal wastewater.

Mechanism of nutrient removal enhancement in low carbon/nitrogen wastewater by a novel high-frequency micro-aeration/anoxic (HMOA) mode.

In this study, a novel high-frequency micro-aeration/anoxic (HMOA) mode with a high aeration frequency (15 times/h) and short aeration duration (Taer = 1 h/cycle) was proposed. Compared with continuous aeration modes, the highest nitrogen and phosphorus removal efficiencies were achieved in the sequencing batch reactor (SBR) under HMOA mode when treating wastewater with carbon/nitrogen (C/N) ratios of 4.5 (85% and 97%, respectively) and 3 (77% and 75%, respectively). Metagenomic analysis was utilized to analyse the microbial metabolic mechanism under the HMOA mode. The results showed that under the HMOA mode, the enhanced transduction and metabolism pathways of nitrate, nitrite, oxygen, phosphorus and acetate provided favourable nutritional conditions for the proliferation of denitrifiers and phosphorus accumulating organisms (PAOs), and simultaneously strengthened the survival capacity of nitrifiers under low dissolved oxygen (DO) conditions. In addition, genes involved in carbon metabolism were upregulated by the HMOA mode, which further increased the utility of carbon sources for denitrifier and PAO metabolism. Consequently, the limited carbon source could be fully utilized in nitrogen and phosphorus removal, which improved the efficiency of treating low C/N wastewater. This study proposed a potential aeration mode for microbial metabolism regulation to enhance nutrient removal in biological wastewater treatment processes.

Hirudin Ameliorates Renal Interstitial Fibrosis via Regulating TGF-ß1/Smad and NF-κB Signaling in UUO Rat Model.

PURPOSE: Hirudin, a polypeptide structure containing 65 amino acids, is a potent natural thrombin inhibitor with anticoagulant property extracted from Hirudo medicinalis. It has been reported to have anti-inflammatory and antifibrotic property. Here we explored the renoprotective effect of hirudin on unilateral ureteral obstruction (UUO) induced renal interstitial fibrosis (RIF). METHODS: Rats were randomly divided into five groups: sham group, UUO alone group, and three UUO + hirudin-treatment groups (10, 20, or 40 IU/kg/d, for 14 continuous days). At the end of the experiment period, animals were sacrificed. Pathologic changes in renal specimens were observed using hematoxylin and eosin (HE) staining and Masson staining. The expressions of collagen III (Col III), fibronectin (FN), α-smooth muscle actin (α-SMA), protease-activated receptor 1 (PAR-1), and proteins in the TGF-ß1/Smad and NF-κB pathways in renal tissues were examined by immunohistochemistry and/or Western blotting. RESULTS: HE and Masson staining showed that hirudin-treated UUO rats had lower extent of renal injury and deposition of extracellular matrix (ECM) in renal interstitium than those in the UUO group. The results of immunohistochemistry and WB indicated decreased protein expressions of Col III, FN, α-SMA, PAR-1, and inflammatory markers such as tumor necrosis factor-α and interleukin-6 after hirudin treatment. Furthermore, hirudin reduced the expressions of transforming growth factor ß1 (TGF-ß1), phosphorylated-Smad2, and phosphorylated-Smad3 in the UUO model. In parallel, we found inhibited nuclear factor-κB (NF-κB) signaling after hirudin treatment, with downregulated protein expressions of P65, phosphorylated-P65, and phosphorylated-iκBα and increased iκBα. CONCLUSION: Hirudin improves kidney injury and suppresses inflammatory response and ECM accumulation in UUO rats; its underlying mechanism may be associated with the inhibition of TGF-ß1/Smad and NF-κB signaling.

Moringa oleifera seed extract protects against brain damage in both the acute and delayed stages of ischemic stroke.

The extract of Moringa oleifera (M. oleifera) seeds exerts various pharmacological effects. Our previous study demonstrated that M. oleifera seed extract (MSE) alleviates scopolamine-induced learning and memory impairment in mice. In the present study, we investigate the neuropharmacological properties of 70% ethanolic MSE in the acute and delayed stages of ischemic stroke. MSE may be effective for the prevention and/or treatment of acute ischemic stroke. The most effective dose was 500 mg/kg, and the therapeutic window seemed to be within 4 h after reperfusion. Additionally, we found that MSE treatment improved animal survival, reversed spatial cognitive impairment and promoted hippocampal neurogenesis and neuroplasticity as well as the cholinergic neurotransmission system during the recovery stages of ischemic stroke. Our findings verified that MSE has neuroprotective effects in both the acute and chronic stages of ischemic stroke. The relevant mechanism of protection may occur by promoting hippocampal neurogenesis and synaptic plasticity as well as improving cholinergic function. These findings suggest that M. oleifera seed extract may be a promising neuroprotective agent for the treatment of ischemic stroke.

Vernonia amygdalina Delile extract inhibits the hepatic gluconeogenesis through the activation of adenosine-5'monophosph kinase.

AIMS: It has been reported that Vernonia amygdalina Delile(VA) presents an anti-diabetic effect, and the effect of VA on lowering glucose is formulated via suppressing the expression of the key hepatic gluconeogenesis enzyme. Therefore, we further explored the probable mechanism of VA on dismissing hepatic gluconeogenesis through the activation of adenosine-5' monophosphate kinase (AMPK) in vivo and in vitro. METHODS: We developed type 2 diabetic mice with STZ and oral administration with VA (50 mg/kg, 100 mg/kg and 150 mg/kg) once a day for 6 weeks. Fasting blood glucose (FBG), fasting insulin (FINS) and oral glucose tolerance tests (OGTT) were conducted. The expression levels of AMPK, phosphoenolpyruvate carboxykinase (PEPCK) and Glucose-6-phosphatase (G6Pase) proteins in live were evaluated by western blot. Then, we further explored the mechanism of VA on hepatic gluconeogenesis in vitro experiments. Glucose production and the expression of AMPK, PEPCK and G6Pase proteins were detected after VA treatment with the presence of the AMPK inhibitor Compound C. KEY FINDINGS: VA reduced FBG and caused a significant improvement in glucose tolerance and insulin resistance (HOMA-IR) in STZ-induced mice. VA inhibited the elevated expression of gluconeogenesis key enzymes (PEPCK and G6Pase) and up-regulated AMPK activity in liver. In palmitic acid (PA)-induced HepG2 cells, VA decreased glucose production and the expression of PEPCK and G6Pase proteins, also activated AMPK pathway. The effects of VA on gluconeogenesis could be reversed by Compound C. CONCLUSION: These results reveal that VA suppresses hepatic gluconeogenesis at least partially through activating the AMPK.

Effects of palm oil blended with oxidized fish oil on growth performances, hematology, and several immune parameters in juvenile Japanese sea bass, Lateolabrax japonicas.

A 60-day feeding trial was conducted to determine the effects of palm oil blended with oxidized and non-oxidized fish oil on growth performances, hematology, and non-specific immune response in juvenile Japanese sea bass, Lateolabrax japonicas. Japanese sea bass (1.73 ± 0.01 g) were fed seven experimental diets containing 100 g/kg of dietary lipid in forms of palm oil (10P), fish oil (10F), fish oil blended with palm oil at different ratios, 6:4 (6F4P) and 4:6 (4F6P), oxidized fish oil (10OF), and oxidized fish oil blended with palm oil at different ratios, 6:4 (6OF4P) and 4:6 (4OF6P). After the feeding trial, the following results were illustrated. No significant effects were observed in survival, feed conversion ratio, condition factor, and hematocrit after feeding with experimental diets for 60 days. The relatively higher specific growth rate and hematology were observed in 6F4P. Furthermore, both palm oil and oxidized fish oil acted as a negatively on serum lysozyme activity (P < 0.05). This study suggested that a ration of 6F4P is recommended as an innocuous ratio for Japanese sea bass. Furthermore, according to the present investigation, palm oil seems to have the ability to improve the protein efficiency when added to oxidized fish diets as well as a positive trend to the growth performance (P > 0.05).