["Load-Unload" Effect of Manganese Oxides on Phosphorus in Surface Water of the Pearl River Estuary].

Phosphorus (P) conveyed by surface runoff plays an essential role in regulating nutrient balance and primary production in estuarine waters. In this study, basic physiochemical properties, total phosphorus (TP, including speciation), particulate iron (PFe), particulate manganese (PMn), and particulate aluminum (PAl) of the surface water in the Pearl River Estuary (PRE) in different seasons were determined to investigate the spatiotemporal distribution characteristics of P and to identify the crucial factor controlling P migration and transformation in the freshwater-saltwater interaction zone. TP concentrations (28.88-233.68 µg·L-1) decreased with increasing salinity gradient owing to deposition and dilution. The proportions of P speciation followed a decreasing order as dissolved inorganic phosphorus (DIP, 37.3%) > particulate inorganic phosphorus (PIP, 22.7%) > dissolved organic phosphorus (DOP, 21.0%) > particulate organic phosphorus (POP, 19.0%). PIP was positively related to PFe, PMn, and PAl (P < 0.05), confirming their concurrent migration behaviors. In addition, the increase in salinity promoted the desorption of phosphate on the suspended particulate matters, which mainly took place near the freshwater-saltwater interface. A significant positive correlation (P < 0.001) between the solid-liquid phase partitioning coefficient (Kd) of phosphate and salinity indicated that PIP was present mainly in more stable forms in the brackish water. Most importantly, a better relationship between Kd and PMn (P < 0.01) supported our scientific hypothesis of the "load-unload" effect of Mn oxides on P:particulate-carrying phosphates transported from the freshwater zone tend to be desorbed and released into the brackish water.

[Pollution and Ecological Risk Assessment and Source Apportionment of Heavy Metals in Sediments of Qingliangshan Reservoir in the Meijiang Basin].

Reservoir sediment is an important sink for pollutants such as heavy metals. Under the changes in acid-base and redox conditions, there is a potential risk of heavy metals release into the water environment, which are transmitted through the food chain and threaten human health. Therefore, this study investigates the Qingliangshan Reservoir in the Meijiang River Basin, and conducts research concerning the contents and speciation of heavy metals in the sediments, potential ecological risks, and source apportionment. This study found that the content of heavy metals in the sediments of the reservoir area was in the order:Xitian tributary > dam front and reservoir center > Xintian-Baishui tributary. There is a large difference in the speciation of heavy metals in the sediments. Zn is mainly acid-soluble and in the residual state, Pb is mainly in an Fe/Mn oxide bound state, Cd is mainly in an acid-soluble state, and Cu, Ni, and Cr are in the residual state. Mainly, the percentage of bioavailable states are Cd(89%) > Pb(76%) > Zn(54%) > Cu(43%) > Ni(28%) > Cr(10%). The geoaccumulation index method shows that the pollution degree of heavy metal elements in reservoir sediments is in the order Cd > Pb > Zn > Cu > Cr > Ni, and the potential hazard ecological index method shows that the pollution degree of heavy metals is Cd > Pb > Cu > Ni > Zn > Cr. The potential ecological risk of Cd in the reservoir sediments is the largest, and the biological impact is greatest. Correlation analysis and principal component analysis results show that heavy metals Cu, Zn, Pb, and Cd in reservoir sediments are mainly from agricultural pollution, and Ni and Cr are mainly from natural background. Combined with the analysis of soil heavy metal content in the watershed, heavy metal pollution in the Qingliangshan Reservoir sediments originates from the effect of rainfall runoff and the use of agricultural chemical fertilizers before flooding in the upstream of the reservoir tributaries. There are significant spatial differences in heavy metal pollution in the sediments of the reservoir area. The Xintian-Baishui River recharge area is the least polluted, and it is closely related to the land use in the controlled watershed, which is mainly forest land, with fewer sources of pollution. The Xitian River replenishment area has the heaviest pollution. It controls many tea gardens and farmlands in the watershed, and the load of external fertilizer pollution is the largest. The pollution degree of heavy metals in front of the dam and the center of the reservoir area is between the two tributary replenishment areas, showing an obvious mixing effect.

Prognostic value of increased expression of RACO-1 in patients with hepatitis B-related hepatocellular carcinoma.

RING domain AP-1 coactivator-1 (RACO-1) is a coactivator that links c-Jun to growth factor signaling and is essential for AP-1 function. This study aimed to investigate the expression and clinical significance of RACO-1 protein in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) in China. A total of 136 tissue samples of HBV-related HCC were detected by immunohistochemistry (including 76 patients in training cohort and 60 patients in validation cohort). Correlation between RACO-1 expression and clinicopathologic features of HBV-related HCC was analyzed in both the cohorts. RACO-1 expression was significantly higher in HBV-related HCC tissues than in adjacent non-tumor liver tissues. All the patients were divided into two groups: the low expression group and the high expression group. RACO-1 expression was significantly related to vascular invasion (P=0.021), tumor numbers (P=0.046), International Union for Cancer Control/American Joint Committee on Cancer stage (P=0.006), cirrhosis (P=0.046), capsular (P=0.039), and Barcelona Clinic Liver Cancer stage (P=0.041) in training cohort. The validation cohort showed the same results. The high RACO-1 expression was the independent prognostic factor for HBV-related HCC patients in both training cohort and validation cohort. Our data implicate RACO-1 as a novel prognostic marker and a potential therapeutic target for HBV-related HCC.

Decrease of RBM4 indicates poor prognosis in patients with hepatocellular carcinoma after hepatectomy.

RNA-binding motif 4 (RBM4) has been reported to play an important role in many human tumors such as lung cancer, breast cancer, ovarian cancer and gastric cancer by regulating alternative splicing and messenger RNA (mRNA) translation. However, little is known about the role of RBM4 in the development of hepatocellular carcinoma (HCC). This study aimed to investigate the expression of RBM4 in HCC tissues. Expression of RBM4 was detected by immunohistochemistry in 95 cases of HCC. Correlations of RBM4 expression with the overall survival and disease-free survival of HCC were also studied. Patients with high RBM4 expression had better overall survival rate and disease-free survival rate than those with low RBM4 expression (P<0.001, P=0.007, respectively). RBM4 expression, together with tumor numbers, capsular formation, vascular invasion and Barcelona clinic liver cancer (BCLC) stage, was an independent prognostic factor for overall survival rate and disease-free survival rate of HCC. Our data implicate RBM4 as a novel prognostic marker and a potential therapeutic target for HCC.

[Temporal-spatial Variation and Source Identification of Hydro-chemical Characteristics in Shima River Catchment, Dongguan City].

Shima River catchment is of strategic importance to urban water supply in Dongjiang portable water source area. To investigate the hydro-chemical characteristics of Shima River, 39 river water samples were collected in February, June and November, 2012 to analyze the major ions (K+, Na+, Ca2+, Mg2+, Cl-, SO4(2-) , HCO3-) and nutritive salts (PO4(3-), NO3- and NH4+) and to discuss the temporal-spatial variation and controlling factors of hydro-chemical composition, relative sources identification of varied ions was performed as well. The results showed that the hydro-chemical composition exhibited significant differences in different periods. The average concentration of total dissolved solid ( TDS) and nutritive salts in different investigated periods followed the decreasing order of November > February > June. The dominant anion of Shima River was HCO3-, and Na+ + K+ were the major cations in February and November which were changed to Ca2+ in June, the hydro-chemical types were determined as HCO(3-)-Na+ and HCO(3-)- Ca2+ in dry (February and November) and rainy (June) seasons, respectively. Spatial variations of concentration of nutritive salts were mainly affected by the discharges of N- and P-containing waste water resulted from human activities. The ratio between N and P of water sample (R7) was 18.4:1 which boosted the "crazy growth" of phytoplankton and led to severe eutrophication. According to Gibbs distribution of water samples, dissolution of hydatogenic rocks was the primary factor to control the major cations of river water in dry season, however, the hydro-chemical composition was significantly affected by the combination of hydatogenic and carbonate rocks in rainy season. The deposition of sea-salts contributed less to chemical substances in river. Correlation analysis revealed that K+, Na+, Mg2+, Cl- and SO4(2-) were partly derived from the application of fertilizer and the discharge of industrial effluent; Waste water of poultry feeding and sanitary wastewater transported large quantities of NH(4+)-N, PO4(3-)-P and NO(3-)-N into the river.

[Temporal-spatial difference of ecotoxicity and heavy metals pollution in Shima catchment, Dongguan].

Shima River, a tributary of Dongjiang River, located in Dongguan City of Guangdong Province, has been seriously polluted in the last 30 years. Water samples were collected from the river and the aquifer and the soil samples were collected as well in the wet (June) and dry (February) season to investigate the temporal and spatial variations of water quality in terms of heavy metal concentrations and inhibition rate of the luminescent bacterium (Vibrio fischeri, LUMIStox 300). Heavy metal concentrations and inhibition rate in river water were found decreasing from the upstream to the downstream, with metal concentrations exceeding the national surface water quality standard (Class I) for all samples and a highest inhibition of 38.34% (equivalent to moderate toxic) at R1 in the dry season. Significant difference (P < 0.01 or P < 0.001) in the wet and dry season was identified in both metal concentrations and inhibition rate, except at R11, which showed a inhibition rate of 15.56%, higher than those in all other samples in the wet season. Inhibition rate at GW4, GW5 and GW6 showed significant difference (P < 0.01 or P < 0.001) in the two periods, and the highest inhibition rate (15.88%) at GW6 in the dry season was considered as low in toxicity. The positive correlations (P < 0.05 or P < 0.01) between heavy metals (Zn, Fe, Mn and Ni) and inhibition rate were identified with correlation coefficients of 0.452, 0.567, 0.726 and 0.475, respectively. Heavy metal pollution of soil (Cu, Ni and Zn) near the river was due to the interaction between the river and the groundwater. Cd was heavily accumulated in the soil, while elevated concentrations of Fe and Mn were found in the river and the groundwater was heavily polluted by Ni.

[Prokaryote diversity in water environment of land-ocean ecotone of Zhuhai City].

By constructing 16S rDNA clone library with PCR-RFLP, the prokaryote diversity in the seawater and groundwater of land-ocean ecotone of Zhuhai City was investigated, and the similarity and cluster analyses were implemented with the database of the sequences in Genbank. In the seawater, Proteobacteria was dominant, followed by Archaeon, Gemmatimonadetes, Candidate division OP3 and OP8, and Planctomycetes, etc.; while in the groundwater, Archaeon was dominant, followed by Proteobacteria, Sphingobacteria, Candidate division OP3, Actinobacterium, and Pseudomonas. The dominant taxa in the groundwater had high similarity to the unculturable groups of marine microorganisms. Large amount of bacteria capable of degrading organic matter and purifying water body existed in the groundwater, suggesting that after long-term evolution, the land-ocean ecotone of Zhuhai City had the characteristics of both land and ocean.

[Spatial characteristics of microbial groups associated with the groundwater flow in a small watershed].

Few reports of microbial groups associated with the groundwater flow system are available in China. 16S rRNA gene library was constructed by the cultured-independent approach to investigate gene sequences of microorganism in groundwater samples from the recharge (R), intermediate (M) and discharge (D) zones of an experimental watershed at Zhuhai campus of Sun Yat-sen University. Proteobacterium, Candidate division OPx, uncultured archaeon (uncultured Crenarchaeote and Euryarchaeote) and Actinobacterium are found predominant in all these three zones with the Proteobacterium accounting for 23.21%, 36.21%, and 28.84% in R, M, D zone respectively. The other predominant microbial groups were identified for varied zones, e. g. Eubacterium and Nitrospira in the R wells, Eubacterium and Acidobacterium in the M wells, and Bacteroidetes bacterium in the D wells. Linkages and potential evolution of microbial groups among three zones were examined by using the genetic neighbor-joining tree. Environmental adaptation along the groundwater flow contributes to the similarity and discrepancy of microorganism in term of the genetic tree, and the ecological functions of the microbial groups need further assessment.