Spatial dynamics and risk assessment of phosphorus in the river sediment continuum (Qinhuai River basin, China).

This study investigated the concentration and fractionation of phosphorus (P) using sequential P extraction and their influencing factors by introducing the PLS-SEM model (partial least squares structural equation model) along this continuum from the Qinhuai River. The results showed that the average concentrations of inorganic P (IP) occurred in the following order: urban sediment (1499.1 mg/kg) > suburban sediment (846.1-911.9 mg/kg) > rural sediment (661.1 mg/kg) > natural sediment (179.9 mg/kg), and makes up to 53.9-87.1% of total P (TP). The same as the pattern of IP, OP nearly increased dramatically with increasing the urbanization gradient. This spatial heterogenicity of P along a river was attributed mainly to land use patterns and environmental factors (relative contribution affecting the P fractions: sediment nutrients > metals > grain size). In addition, the highest values of TP (2876.5 mg/kg), BAP (biologically active P, avg, 675.7 mg/kg), and PPI (P pollution index, ≥ 2.0) were found in urban sediments among four regions, indicating a higher environmental risk of P release, which may increase the risk of eutrophication in overlying water bodies. Collectively, this work improves the understanding of the spatial dynamics of P in the natural-rural-urban river sediment continuum, highlights the need to control P pollution in urban sediments, and provides a scientific basis for the future usage and disposal of P in sediments.

Contribution of 1O2 in the efficient degradation of organic pollutants with Cu0/Cu2O/CuO@N-C activated peroxymonosulfate: A Case study with tetracycline.

Peroxymonosulfate-mediated advanced oxidation processes (PMS-AOPs) degrading organic pollutants (Tetracycline (TC) as an example) in water with singlet oxygen (1O2) as the main reactive oxygen has received more and more attention. However, the generation mechanism of 1O2 is still unclear. Consequently, this study investigates the 1O2 formation mechanism during the activated PMS process using a nitrogen-copper-loaded carbon-based material (Cu0/Cu2O/CuO@N-C), synthesized by thermally decomposing organobase-modified HKUST-1 via a one-pot method. It was discovered that incorporating an organobase (Benzylamine) into the metal organic framework (MOF) precursor directs the MOF's self-assembly process and supplements its nitrogen content. This modification modulates the Nx-Cu-Oy active site formation in the material, selectively producing 1O2. Additionally, 1O2 was identified as the dominant reactive oxygen species in the Cu0/Cu2O/CuO@N-C-PMS system, contributing to TC degradation with a rate of 70.82%. The TC degradation efficiency remained high in the pH range of 3-11 and sustained its efficacy after five consecutive uses. Finally, based on the intermediates of TC degradation, three possible degradation pathways were postulated, and a reduction in the ecotoxicity of the degradation products was predicted. This work presents a novel and general strategy for constructing nitrogen-copper-loaded carbon-based materials for use in PMS-AOPs.

Spinel ferrites materials for sulfate radical-based advanced oxidation process: A review.

In the past decade, the sulfate radical-based advanced oxidation processes (SR-AOPs) have been increasingly investigated because of their excellent performance and ubiquity in the degradation of emerging contaminants. Generally, sulfate radicals can be generated by activating peroxodisulfate (PDS) or peroxymonosulfate (PMS). To date, spinel ferrites (SF) materials have been greatly favored by researchers in activating PMS/PDS for their capability and unique superiorities. This article reviewed the recent advances in various pure SF, modified SF, and SF composites for PDS/PMS activation. In addition, synthesis methods, mechanisms, and potential applications of SF-based SR-AOPs were also examined and discussed in detail. Finally, we present future research directions and challenges for the application of SF materials in SR-AOPs.

Effect of Tongxinluo on pulmonary hypertension and pulmonary vascular remodeling in rats exposed to a low pressure hypoxic environment.

ETHNOPHARMACOLOGICAL RELEVANCE: Tongxinluo (TXL), which is a Chinese medicine rooted from traditional used herbs, has been used in clinic to treat cardiovascular and cerebrovascular diseases. However, it remains unknown whether TXL alleviates low pressure hypoxic pulmonary hypertension. AIM OF THE STUDY: Here, we aimed to observe the influence of TXL on pulmonary hypertension in a rat model that exposed to high altitude environment characterized by low pressure hypoxia. MATERIALS AND METHODS: A total of 32 male Sprague-Dawley rats were divided into four groups: control group (normal pressure and normoxia), pulmonary hypertension group (PAH, the parameter is equal to that in altitude 5000m), TXL group (rats living in environment equal to that at altitude of 5000m received TXL treatment), vardenafil group (VDNF, rats living in environment equal to that altitude of 5000m received vardenafil treatment). The high altitude environment was created in chamber by adjusting the inner pressure and oxygen content concomitantly. Before entering the chamber, the TXL group was given TXL (1.2gkg-1d-1) for 28 days, and the VDNF group was given VDNF (0.1gkg-1d-1) for 28 days. After 28 days, the mean pulmonary artery pressure (mPAP) and right ventricular pressure was measured using right heart catheterization. The weight of the right ventricle (RV), left ventricle (LV) and interventricular septum (IVS) was measured, and the right ventricular mass index was calculated. Lung tissue was subjected to hematoxylin and elastic fiber staining, and the medial wall thickness (MT), medial wall cross-sectional area (MA), MT%, and MA% were measured. Proliferative activity within the pulmonary arteries was quantified by Ki67staining. RESULTS: After 28 days, as compared with that in normal control group, animals living in the chamber (PAH group) showed a significant increase in mPAP( 47.5mmHg versus 18mmHg), RV/LV+IVS (0.45 versus 0.21) and MA% (78% versus 44%), respectively. Administration of TXL resulted in a significant decrease of 20mmHg in mPAP, returning of RV/LV+IVS to 0.27, and a 40% reduction in MT% compared with that in PAH group. In the VDNF group, RV/LV+IVS and MT% was 0.268 and 38.77, significantly lower than that in PAH group. While, mPAP increased by 12.5mmHg with treatment by VDNF. In contrast to the PAH group, alpha- Smooth Muscle Actin (α-SMA reduced by 19% in the TXL group (p=0.005) and 16% in the VDNF group (p=0.01). Ki67 expression in the VDNF group was significantly lower than the PAH group (P<0.01). Ki67 expression in the TXL group was significantly lower than the PAH group (P<0.01). Compared with the VDNF group, the indexes above reduced in the TXL group. Our results indicate that TXL significantly reduces pulmonary artery pressure, right ventricular hypertrophy, pulmonary small artery wall thickness, and luminal stenosis. In addition, smooth muscle proliferation markedly decreased and muscular artery decreased. However, TXL was unable to restore parameters to control levels. CONCLUSIONS: The automatic-adjusted low pressure hypoxic chamber was capable of establishing a pulmonary hypertension rat model at an altitude of 5000m. Compared with VDNF, TXL decreased mPAP and right ventricular hypertrophy index (RVHI) in the pulmonary hypertension rat model, and prevented vascular remodeling by reducing small pulmonary artery thickening, smooth muscle thickening and proliferation. Thus, TXL may be a potential treatment for pulmonary hypertension.

Activation of transcription factor AP-1 in response to thermal injury in rat small intestine and IEC-6 cells.

BACKGROUND: Our previous studies indicated that heat stress can cause significant damage to the intestinal epithelium and induce differential expression of many genes in rat small intestine. The transcription factors AP-1 and NF-κB, which act as important mediators by binding to specific DNA sequences within gene promoters, regulate the transcription of genes associated with immune regulation, stress response and cell fate. METHODS: To determine whether AP-1 and NF-κB are involved in hyperthermia-induced injury in rat small intestine and IEC-6 cells, we investigated their activity, and the expression of related proteins, by electrophoretic mobility shift assays and western blotting, respectively. RESULTS: Heat stress resulted in severe damage to the epithelium of the small intestine. The cell morphology and viability were obviously altered when IEC-6 cell was exposed to hyperthermia. AP-1 was activated in the small intestine of heat-stressed rats, as was phosphorylation of the JNK signaling pathway. In IEC-6 cell line, AP-1 activation in groups exposed to 42 °C for 1 h, 2 h and 4 h was significantly increased. In contrast, NF-κB was not activated in both in vivo and in vitro models. CONCLUSION: These results reveal that AP-1 is likely to play an important role in regulating gene transcription in rat small intestine and IEC-6 cells during exposure to heat stress.

Molecular characterization and primary functional analysis of PeVDE, a violaxanthin de-epoxidase gene from bamboo (Phyllostachys edulis).

KEY MESSAGE: PeVDE was expressed primarily in bamboo leaves, which was up-regulated under high light. The protein encoded by PeVDE had enzyme activity of catalyzing violaxanthin (V) to zeaxanthin (Z) through antheraxanthin (A) as assay shown in vitro. Violaxanthin de-epoxidase (VDE), a key enzyme of xanthophyll cycle, catalyzes conversion from violaxanthin (V) to zeaxanthin (Z) through antheraxanthin (A) to protect photosynthesis apparatus. A cDNA, PeVDE, encoding a VDE was isolated from bamboo (Phyllostachys edulis) by RT-PCR and RACE methods. PeVDE is 1,723 bp and contains an ORF encoding 451 amino acids, with a transit peptide of 103 amino acids. The mature protein is deduced to have 348 amino acids with a calculated molecular weight of 39.6 kDa and a theoretic isoelectric point of 4.5. Semi-quantitative RT-PCR assay indicated that the highest expression level of PeVDE was in leaf, which agreed with the accumulation pattern of PeVDE protein. Real time PCR results showed that PeVDE was up-regulated and reached the highest level after the treatment (1,200 µmo1 m(-2) s(-1)) for 2 h, then decreased and kept at the level similar to that of 0.5 h after treatment for 8 h. To investigate the function of PeVDE, mature protein was heterologously expressed in Escherichia coli and the enzymatic activity assay was carried out using V as substrate. The pigments that formed in the reaction mixture were extracted and analyzed by HPLC method. Besides V, A and Z were detected in the reaction mixture, which indicated that the recombinant protein exhibited enzymatic activity of catalyzing V into Z through A. This study indicates that PeVDE functions through regulating the components of xanthophyll cycle, which might be one of the critical factors that contribute to the growth of bamboo under naturally varying light conditions.

Insulin-transferrin-selenium (ITS) improves maturation of porcine oocytes in vitro.

The objective of this study was to determine if insulin-transferrin-selenium (ITS) promoted a nuclear and cytoplasmic maturation of porcine oocytes that better supports subsequent embryonic development. The rate of oocyte in vitro maturation (IVM) in an experimental group treated with hormones for 42 h was significantly increased compared with that in a control group without hormone treatment (47.8% vs. 11.7%, respectively, p < 0.05). Following reduction of the hormone treatment period from 42 h to 21 h, which included both the first 21 h period of hormones treatment (45.4%) and the second 21 h period of hormone treatment (44.8%), the rate of oocyte IVM was still higher than that of the control group (p < 0.05). To improve porcine oocyte nuclear maturation, 1% ITS was added to medium supplemented with hormones. The rate of nuclear maturation in the ITS-treated group was significantly higher than in the ITS-untreated group (78.6% vs. 54.4%, respectively, p < 0.05). ITS treatment also significantly reduced the per cent of oocytes with type I and type III cortical granule (CG) distribution, respectively, and significantly increased the per cent of oocytes with type II CG distribution (85.3%). These observations indicated that the synchronization rates of nuclear and ooplasmic maturation reached 67.04% (78.56 × 85.33%). In conclusion, the combination of modified Tissue Culture Medium-199 (mM199) + 10 ng/ml epidermal growth factor (EGF) + 10 IU/ml pregnant mare serum gonadotrophin (PMSG) + 10 IU/ml human chorion gonadotrophin (hCG) + 2.5 IU/ml follicle stimulating hormone (FSH) + 1% ITS is suitable for culturing porcine oocytes in vitro, and effectively enhances porcine oocyte nuclear and cytoplasmic maturation.