ABSTRACT
Nitrate pollution in groundwater has become a global concern. One of the most important issues in controlling the nitrate pollution of groundwater is to identify the pollution source quickly and accurately. In this review, we firstly summarized the isotopic background values of potential sources of nitrate pollution in groundwater in 17 provinces (cities, autonomous regions) and 29 study areas in China, which could provide the fundamental database for subsequent research. Secondly, we reviewed the research progress of nitrate isotopes combined with multiple tracers for tracing nitrate in groundwater, and discussed their applicable conditions, advantages, and disadvantages. We found that halides and microorganisms combined with nitrate isotopes could accurately trace the pollution sources of domestic sewage, excrement and agricultural activities. The combination of Δ17O and nitrate isotopes could effectively distinguish the source of atmospheric deposition of nitrate in groundwater. The combination of groundwater age and nitrate isotopes could further determine the time scale of nitrate pollution. In addition, we summarized the application cases and compared the characteristics of mass balance mixing model, IsoSource model, Bayesian isotope mixing model, and EMMTE model for quantitative identification of nitrate pollution in groundwater. For the complexity and concealment of groundwater pollution sources, the coupling of nitrate isotopes with other chemical and biological tracing methods, as well as the application of nitrate isotope quantitative models, are effective tools for reliably identifying groundwater nitrate sources and transformation processes.
Subject(s)
Environmental Monitoring , Groundwater , Nitrates , Water Pollutants, Chemical , Groundwater/analysis , Groundwater/chemistry , Nitrates/analysis , Environmental Monitoring/methods , Water Pollutants, Chemical/analysis , China , Oxygen Isotopes/analysis , Isotopes/analysisABSTRACT
Background: Recently, several studies have demonstrated that caveolin-1 overexpression is involved in apoptosis resistance, angiogenesis, and invasiveness in hepatocellular carcinoma (HCC). However, the mechanisms underlying caveolin-1-mediated tumor progression remain unclear. Methodogy. Lentiviral vectors were used to construct caveolin-1 small interfering RNA- (siRNA-) expressing cells. Secreted VEGF levels in SMMC7721 cells were evaluated by enzyme-linked immunosorbent assay (ELISA). SMMC7721 cell proliferation, cycle, apoptosis, and invasiveness were detected by MTT, flow cytometry, Annexin V-FITC/PI, and invasion assay, respectively. Phospho-eNOS levels in human umbilical vein endothelial cells (HUVECs) cocultured with SMMC7721 cell supernatants were analyzed by Western blot. Capillary-like tubule formation assay was performed to analyze endothelial tubular structure formation in HUVECs treated with supernatants from caveolin-1 siRNA-expressing SMMC7721 cells. SMMC7721 implantation and growth in nude mice were observed. Angiogenesis in vivo was analyzed by immunohistochemical angiogenesis assay. Results: Caveolin-1 siRNA-expressing SMMC7721 cells secreted reduced levels of VEGF. Caveolin-1 RNAi also caused an inhibition of SMMC7721 cell proliferation and cell cycle progression that was accompanied by increased apoptosis. Supernatants from caveolin-1 siRNA-expressing SMMC7721 cells inhibited cell cycle progression and decreased phospho-eNOS levels in HUVECs. Endothelial tubular structure formation in HUVECs treated with supernatants from caveolin-1 siRNA-expressing SMMC7721 cells was considerably reduced. Caveolin-1 siRNA-expressing SMMC7721 cells also showed reduced tumorigenicity and angiogenesis induction in vivo. Conclusion: Our results reveal a novel mechanism, whereby caveolin-1 positively regulates human HCC cell invasiveness by coordinating VEGF-induced angiogenesis.
Subject(s)
Angiogenesis Inhibitors/genetics , Carcinoma, Hepatocellular/genetics , Caveolin 1/metabolism , Liver Neoplasms/genetics , Neoplasm Invasiveness/genetics , Animals , Apoptosis/genetics , Cell Cycle/genetics , Cell Line, Tumor , Cell Proliferation/genetics , Enzyme-Linked Immunosorbent Assay , Human Umbilical Vein Endothelial Cells , Humans , Mice , Mice, Nude , Neovascularization, Pathologic/genetics , RNA, Small Interfering , Signal Transduction/genetics , Vascular Endothelial Growth Factor A/metabolismABSTRACT
Genetic variation of three microsatellite loci BMS2258, SOD1, and BM723, which were closely correlated with GSH-Px, SOD, and Na+/K+-ATPase genes, was analyzed in 130 Holstein cows by PCR and nondenaturing polyacrylamide gel-electrophoresis. Polymorphic information content, effective number of alleles and heterozygosity of these microsatellite loci were determined. Relationships of the three microsatellite loci with enzyme activities and daily milk yields in Holstein cows were analyzed by least squares linear model. The results showed significant correlations of the three microsatellite loci with their corresponding enzyme activities and daily milk yield in summer and fall (Plt;0.05). The least square means of GSH-Px activities and daily milk yields for BMS2258 (182 bp/164 bp), SOD activities for SOD1 (148 bp/148 bp), and daily milk yields for SOD1 (148 bp/146 bp), Na+/K+-ATPase activities and daily milk yields for BM723 (161 bp/111 bp) were relatively higher. These genotypes were the most favorable genotypes for enzyme activity and daily milk yields in summer and fall, which could be references for marker assisted selection in heat resistance traits in dairy cattle.
