Fluoride contents in commonly used commercial phosphate fertilizers and their potential risks in China.

The application of phosphate fertilizer is an important source of anthropogenic fluoride in agricultural soil. However, relatively few studies have examined the fluoride content of phosphate fertilizers, and that has limited our understanding of the phosphate fertilizer contribution to soil fluoride accumulation and distribution. To examine this problem, we first quantified the total fluoride (TF) and water-soluble fluoride (WF) contents of six of the most commonly used commercial phosphate fertilizers in China (potassium dihydrogen phosphate (MKP), calcium superphosphate (SSP), monoammonium phosphate (MAP), diammonium phosphate (DAP), ternary compound fertilizer (NPK), and water-soluble macroelement fertilizer (WSF)). After calculating the [P2O5]/TF ratio for each of those fertilizers, we used those ratios and the average P2O5 application per crop of five typical crops grown in China (apples, greenhouse vegetables, wheat, corn, and rice) to estimate the annual fluoride accumulations in their soils after application of each type of phosphate fertilizer. Among the six fertilizer types, SSP, DAP, and NPK had much higher total fluoride and water-soluble fluoride contents than MKP, MAP, and WSF had. During crop production, the risk of fluoride accumulation was lower with MKP, MAP, and WSF (high [P2O5]/TF ratios) and higher with SSP, DAP, and NPK (low [P2O5]/TF ratios), especially in cash crops (fruit and greenhouse vegetables), which traditionally have unreasonably high P2O5 applications. Based on our findings, we proposed steps that should be taken to help effectively mitigate fluoride accumulation in China's agricultural soils.

Fluoride accumulation characteristics in a northern China apple orchard that has had long-term phosphate fertilization.

Phosphate fertilizer can cause fluoride accumulation in the soil and excessive fluoride poses potential risks to soil and food crop safety. However, the effects of fertilization on soil and fruit fluoride accumulations through long-term positioning trials, especially in high-fertilizer application situations such as apple orchards, have received little attention. To close this knowledge gap, we conducted a field experiment to demonstrate the effects among five long-term (13-year) fertilizer treatments on fluoride accumulations at different soil depths and in the fruits of an apple orchard in Baishui, Shaanxi, China. The five treatments included no fertilization (CK); manure application (M); nitrogen and phosphate fertilization (NP); nitrogen, phosphorus, and potassium fertilization (NPK); and groundcover with nitrogen and phosphate fertilization (GNP). The results confirmed that all phosphate fertilizer treatments (NP, NPK, and GNP) had significant increases in total fluoride (TF) and water-soluble fluoride (WF) accumulations in the topsoil (0-20 cm). Among the phosphate fertilizer treatments, NP topsoil accumulated the most TF and WF, 79.4 and 7.7 mg kg-1 more than CK, respectively, and an average annual TF increase of 6 mg kg-1. However, the M treatment both experienced reduced fluoride content in the topsoil and had TF and WF contents 8.1 and 0.67 mg kg-1 lower than CK, respectively. There was no significant difference between all fertilizer treatments and CK in apple fluoride content. Furthermore, TF and WF accumulated mainly in the topsoil and the differences in soil fluoride content among the treatments decreased with soil depth. These findings showed that long-term phosphate fertilization increases the risk of fluoride accumulation in orchard topsoil. Altogether, these results improve the understanding of the characterization of soil and fruit fluoride accumulations in apple orchards under long-term fertilizer conditions and provide new insights into the use of manure as a possible alternative fertilization strategy that reduces fluoride accumulation.

Dissolved greenhouse gas emissions from agricultural groundwater irrigation in the Guanzhong Basin of China.

While evidence indicates that groundwater is a potential source for greenhouse gas (GHG) emissions, information for such emissions in groundwater used for irrigation is lacking. Based on 23 wells in the mid-western Guanzhong Basin of China, we investigated the dissolved CO2, N2O, and CH4 distributions in groundwater, their relationships with water indicators, and emission fluxes during flood irrigation. We found zero methane, but CO2 and N2O were 30 and 25 times, respectively, supersaturated compared to atmospheric concentrations. Dissolved N2O in groundwater was positively correlated with NO3--N (P = 0.009), while CO2 depended mainly on low pH and high dissolved inorganic carbon. The CO2 and N2O emission fluxes detected in wellheads, especially in shallow wells, implied potential emissions. Flood irrigation experiments showed that 24.55% of dissolved CO2 and 36.81% of dissolved N2O in groundwater was degassed immediately (within 12 min of irrigation) to the atmosphere. Our study demonstrates that direct GHG emissions from groundwater used for agricultural irrigation in the Guanzhong Basin are potentially equivalent to about 2-4% of the GHG emissions from 3 years of fertilizer use on these farmlands, so further research should focus on optimizing irrigation strategies to mitigate GHG emissions.

Solid digestate biochar amendment on pig manure composting: Nitrogen cycle and balance.

Effect of solid digestate biochar (DB) on nitrogen cycle and balance was evaluated during composting by adding DB into mixtures of pig manure and Lycium chinensis branch filings. Results indicated that DB addition improved composting microenvironment and increased the total N content of the final product. Furthermore, N balance calculation indicated that the NH3 and N2O emissions accounted for 72.14%-81.39% and 0.49%-2.37% of the total N loss without DB addition, respectively. After using DB, the N reductions in the form of NH3 and N2O reduced from 10.78% to < 5.73% and from 0.34% to < 0.041% of total N, respectively. Addition of DB affected N fixation with 92.32%-93.67% of total N fixed in the compost than that of the T1 treatment (85.63%). DB amendment enhanced the aerobic bacterial communities and hindered anaerobic bacterial growth, thus benefiting the NH3 and N2O emission mitigation and N conservation.

Clinical significance of the combined measurement of serum B7-H1 and interleukin-10 in colorectal cancer patients.

Colorectal cancer (CRC) patients have been shown to express a cytokine signature that is detectable in serum and contributes to cancer pathogenesis. The objective of this study was to evaluate the potential clinical significance of preoperative circulating cytokine levels in CRC patients.The expression of serum B7-H1 and IL-10 was assessed by ELISA in 89 patients and 64 health volunteers. As a control marker, CEA serum levels were measured by electrochemical luminescence detection. The receiver operating characteristic (ROC) curve was used to analysis to demonstrate the potential diagnostic value of these biomarkers.The expression of serum B7-H1 was significantly increased in CRC patients (P = .001) and associated with the progression of TNM stage and a positive association with serum IL-10 levels was also evident. Furthermore, serum B7-H1 and IL-10 expression was not influenced by age, gender, tumor location, or mass, whereas a relationship existed with tumor metastasis and TNM stage. The serum levels of B7-H1 and IL-10 on the 7th postoperative day were significantly decreased compared with that of preoperative serum levels (P = .001, P = .003 respectively). The area under the ROC curves (AUC) for B7-H1 and IL-10 were 0.7063 and 0.5706, respectively. The optimal sensitivity and specificity of B7-H1 for discriminating between colon cancer patients and healthy controls were 85.21% and 56.43%, respectively, using a cut-off value of 3.46 ng/mL. However, the combined ROC analysis using B7-H1 and IL-10 revealed an AUC of 0.8791, with a sensitivity of 90.63% and a specificity of 75.18%.The outcomes of the present study demonstrate the clinical significance of serum B7-H1 and IL-10 concentrations. Combined detection of B7-H1 plus IL-10 showed significantly increased sensitivity and specificity for discriminating between colorectal cancer patients and healthy controls compared these markers detection individual. The measurement of B7-H1 or IL-10 in sera following surgery may provide an additional tool for assessing the curative effects of surgery in CRC patients.

B7-H4 facilitates proliferation and metastasis of colorectal carcinoma cell through PI3K/Akt/mTOR signaling pathway.

B7-H4 is over-expressed in various tumors and may affect many aspects of cancer biology. Our previous studies have reported that the over-expressed B7-H4 in serum or tumor tissue of colorectal carcinoma (CRC) patients was closely related to CRC progression. However, B7-H4 in cell biological characteristics of CRC is not well studied. Here, we investigate the effect of the B7-H4 on cell proliferation, migration and its expression regulated by PI3K/Akt/mTOR signaling pathway in CRC. Firstly, pSilencer 4.1-B7-H4-shRNA vector was constructed and stable transfection was performed on HT-29 cells. Secondly, cell proliferation, cell cycle, cell apoptosis and cell migration were evaluated after B7-H4 silencing, and the expression of Bcl-2, caspase-3, MMP-2 and MMP-9 was also measured. Finally, the regulation of B7-H4 by PI3K/Akt/mTOR signaling pathway was measured followed by treatment with or without PI3K/Akt and mTOR inhibitor. The results showed that the viability of HT-29 cells was significantly decreased after B7-H4 silencing (P < 0.05). B7-H4 silencing significantly increased the apoptosis rate and caspase-3 protein expression while decreased Bcl-2 protein expression (P all < 0.05). B7-H4 silencing also significantly reduced the migration of HT-29 cells (P < 0.01) and the secretion of MMP-2 or MMP-9 (P all < 0.05). Following treatment with PI3K/Akt and mTOR inhibitor in HT-29 cells, the expression of B7-H4 was significantly downregulated compared with untreated group (P all < 0.05). Our results strongly suggest that B7-H4 may be involved in cell proliferation and migration by PI3K/Akt/mTOR signaling pathway. Therefore, blocking B7-H4 signaling might be a novel treatment strategy for CRC.

IL-17F expression correlates with clinicopathologic factors and biological markers in non-small cell lung cancer.

Interleukin-17 F (IL-17F) is a pro-inflammatory cytokine that participate in inflammatory responses. Studies showed that IL-17F is likely involved in tumor development, but the biological function of IL-17F in non-small cell lung cancer (NSCLC) is unclear. The aim of this study was to explore the biological role of IL-17F in NSCLC and investigate its correlation with biological markers CD31, P53, Ki-67 and E-cadherin. Paraffin-embedded tumor tissues from 55 NSCLC patients were collected to detect proteins expression using immunohistochemistry (IHC). 12 normal lung tissues samples were used as control. IHC results showed that the expression of IL-17F in NSCLC cells (61.8%) was significantly higher compared with normal lung tissues (25.0%) (P < 0.05). The expression of IL-17F was positively associated with tumor differentiation and negatively associated with lymph node metastasis and TNM staging (P all < 0.05). Multivariate analysis showed that IL-17F expression was an independent factor associated with TNM staging (P < 0.01). Pearson's correlation analysis showed a negative correlation between IL-17F and CD31 expression and a positive correlation between IL-17F and E-cadherin expression (P all < 0.05). There was no relationship between IL-17 F and P53 or Ki-67 expression in NSCLC tissues (P > 0.05). These data suggest that IL-17 F may be considered as a potential marker for predicting the progression of NSCLC.

Clinical Value of Combined Determination of Serum B7-H4 with Carcinoembryonic Antigen, Osteopontin, or Tissue Polypeptide-Specific Antigen for the Diagnosis of Colorectal Cancer.

AIM: B7-H4 is member of the B7 family that negatively regulates the immune response, which are associated with tumor development and prognosis. The present study is aimed at examining serum B7-H4 expression and exploring its contribution to diagnosis in patients with colorectal cancer. METHODS: We determined serum expressions of B7-H4, carcinoembryonic antigen (CEA), osteopontin (OPN), and tissue polypeptide-specific antigen (TPS) in 59 patients with colorectal cancer and 29 healthy volunteers and analyzed the diagnostic value of B7-H4 combined with CEA, OPN, or TPS detection for colorectal cancer. B7-H4, OPN, and TPS serum expressions were measured by enzyme-linked immunosorbent assay, and CEA was measured by electrochemical luminescence detection. RESULTS: Serum B7-H4 levels were significantly higher in colorectal cancer patients compared with paired normal controls (P = 0.001). B7-H4 serum level was positively correlated with infiltration depth, tumor masses, and lymph node metastasis (P = 0.004, P = 0.016, and P = 0.0052, respectively). We also detected serum expression of B7-H4 before and after radical resection and showed that B7-H4 levels decreased significantly during the first week postoperation (P = 0.0064). We used receiver operating characteristic (ROC) curve analysis to indicate the potential diagnostic values of these markers. The areas under the ROC curves (AUC) for B7-H4, OPN, TPS, and CEA were 0.867, 0.805, 0.812, and 0.833, respectively. The optimal sensitivity and specificity of B7-H4 for discriminating between colon cancer patients and healthy controls were 88.2% and 86.7%, respectively, using a cut-off of value of 78.89 ng/mL. However, combined ROC analysis using B7-H4 and CEA revealed an AUC of 0.929, with a sensitivity of 98.9% and a specificity of 80.4% for discriminating colon cancer patients from healthy controls. CONCLUSIONS: B7-H4 was highly expressed in the serum in colorectal cancer patients. Detection of B7-H4 plus CEA showed significantly increased sensitivity and specificity for discriminating between colorectal cancer patients and healthy controls compared to individual detection of these markers. Combined detection of serum B7-H4 and CEA may thus have the potential to become a new laboratory method for the early clinical diagnosis and prognostic evaluation of colorectal cancer.