Organic carbon in wet deposition of an urbanized coastal bay, North China: Flux, sources and biogeochemical implications.

The process of atmospheric organic carbon (OC) entering the ocean through wet deposition plays a crucial role in the global carbon cycle. To gain insights into the biogeochemical dynamics of OC at the land-sea margin, we conducted an extensive four-year investigation on precipitation OC in Jiaozhou Bay (JZB). The results showed that the volume-weighted mean concentration of particulate OC (POC) and dissolved OC (DOC) in precipitation were 0.38 and 2.06 mg C L-1 with an average wet deposition flux of OC for 2666.5 mg C m-2 yr-1. The source of POC in precipitation is predominantly by the C3 plant emission and burning and fossil fuel combustion. Wet deposition contributed 986.6 t yr-1 of OC of which 506.3 t yr-1 of bioavailable DOC, which could have significant implications for carbon cycle in the JZB. This study could enhance the understanding of the marine atmospheric OC in coastal areas.

ASF1B acted as a prognostic biomarker for stomach adenocarcinoma.

Stomach adenocarcinoma (STAD) has a high mortality rate due to the lack of highly sensitive biomarkers. Therefore, the search for potential tumor markers is of great value. ASF1B is a prognostic marker for a variety of tumors, while the prognostic value and immune microenvironment of ASF1B in STAD remain unclear, and to be determined. Kaplan-Meier analysis was performed to analyze the prognostic role of ASF1B in STAD. Functional enrichment of ASF1B was explored with GO and KEGG pathway analysis. We also explored the correlation between ASF1B expression and immune infiltration in STAD. ASF1B was significantly upregulated in STAD tissues and high expression of ASF1B indicated a poor overall survival, progression-free survival, and first progression rate in STAD. The functional enrichment analysis of ASF1B and related genes showed high enrichment in the cell cycle and DNA repair, and the ASF1B high expression group was also mainly enriched in pathways such as the cell cycle. Analysis of tumor immune infiltration showed that ASF1B expression was significantly associated with the majority of immune cell infiltration in STAD. Moreover, STAD patients with high ASF1B expression had a higher tumor mutation burden score, microsatellite instability score, PD-1 immunophenoscore, and immune checkpoint expression. Our results suggest that ASF1B was an independent prognostic factor for STAD as well as a potential target for immunotherapy.

Behavioral and ecotoxicology of sulfonamide metabolites in the aquatic environment.

Sulfonamides (SAs) are the first broad-spectrum synthetic antimicrobial agents used in human health and veterinary medicine. The majority of SAs entering human body is discharged into aquatic environment in the form of parent material or metabolites. The residues of SAs and their metabolites in the aquatic environment and the development of drug resistance can be serious threats to ecosystems and human health. We summarized recent advances in the research of SAs. The main metabolite types of SAs and the distribution characteristics of metabolites in different aquatic environments were introduced. The ecotoxicology of SAs metabolites, especially the distribution and hazards of sulfonamide resistance genes (sul-ARGs), were discussed with emphasis. Finally, the future research works were proposed. This paper could provide basic information for further research on SAs.

Carbon Isotopic Evidence for Gas Hydrate Release and Its Significance on Seasonal Wetland Methane Emission in the Muli Permafrost of the Qinghai-Tibet Plateau.

In order to determine the significant role of gas hydrate in seasonal wetland methane emission at the drilling-affected permafrost, the carbon isotopic monthly field monitoring of methane (CH4), as well as carbon dioxide (CO2), emitted from near-surface soil and a gas hydrate drilling well (DK-8) was conducted in the Muli permafrost of the Qinghai-Tibet Plateau. The methane source effused from the well DK-8 was calculated as -25.9 ± 1.4‱ and -26.5 ± 0.5‱, respectively, by the Keeling and Miller Tans plots, with the carbon isotope fractionation (εC) between CO2 and CH4 from -25.3‱ to -32.1‱. The carbon isotopic signatures are indicative of thermogenic origin associated with gas hydrate dissociation. The near-surface soil-emitted methane has δ13CCH4 values between -52.0 ± 1.2‱ and -43.2 ± 1.8‱ with the heaviest in December and the lightest in July. Further, the εC values of near-surface soil-emitted gases were between 28.6‱ and 47.9‱, significantly correlated with the δ13CCH4 values. The linear correlation between εC and δ13CCH4 values indicated binary end-member of microbial and thermogenic sources control the seasonal variation of wetland methane emission. The thermogenically derived methane was identified as the dominant methane source in autumn and winter, compared with the increasing contribution of microbially derived methane in spring and summer. The finding provides reliable evidence for gas hydrate release on the seasonal wetland methane emission in the Muli permafrost affected by drilling activities. The combined application of εC and δ13CCH4 to distinguish thermogenic from biogenic methane is well established and powerful in complex environments, which can provide an improved constraint on source apportionment for wetland emitted methane in the permafrost of the Qinghai-Tibet Plateau.

A Novel Multidrug Combination Mitigates Rat Liver Steatosis Through Activating AMPK Pathway During Normothermic Machine Perfusion.

BACKGROUND: Hepatic steatosis is now the leading cause of liver discards in deceased donors. Previous studies [Yarmush formula (Y) defatting] have successfully reduced the fat content by treating rat steatotic livers on extracorporeal normothermic machine perfusion (NMP) with a multidrug combination including the GW compounds that were linked to an increased risk of carcinogenesis. METHODS: We developed a novel multidrug combination by replacing the GW compounds with 2 polyphenols, epigallocatechin-3-gallate (E) and resveratrol (R). Sixteen rat livers were placed on NMP and assigned to control, Y defatting, Y + E + R defatting, or Y'-GW + E + R defatting groups (Y'-GW = 90% dose-reduced Y defatting, n = 4/group). RESULTS: All livers in defatting groups had significant decreases in hepatic triglyceride content at the end of the experiment. However, livers treated with our novel Y'-GW + E + R combination had evidence of increased metabolism and less hepatocyte damage and carcinogenic potential. Our Y'-GW + E + R combination had increased phosphorylation of AMP-activated protein kinase (P = 0.019) and acetyl-CoA carboxylase (P = 0.023) compared with control; these were not increased in Y + E + R group and actually decreased in the Y group. Furthermore, the Y'-GW + E + R group had less evidence of carcinogenic potential with no increase in AKT phosphorylation compared with control (P = 0.089); the Y (P = 0.031) and Y + E + R (P = 0.035) groups had striking increases in AKT phosphorylation. Finally, our Y'-GW + E + R showed less evidence of hepatocyte damage with significantly lower perfusate alanine aminotransferase (P = 0.007) and aspartate aminotransferase (P = 0.014) levels. CONCLUSIONS: We have developed a novel multidrug combination demonstrating promising defatting efficacy via activation of the AMP-activated protein kinase pathway with an optimized safety profile and reduced hepatotoxicity during ex vivo NMP.

Nitrogen loss process in hypoxic seawater based on the culture experiment.

The oxygen minimum zones (OMZs) and other hypoxic seawaters are considered as the main areas of oceanic nitrogen loss. The laboratory simulation culture was conducted to study the main reactions, rates and proportions of dissolved inorganic nitrogen (DIN) in different dissolved oxygen concentrations seawater, with aim of clarifying the process of nitrogen loss in hypoxic seawater. The results showed that the change of DIN in hypoxic water could be divided into three stages. In the first stage, the main reactions were the dissimilatory nitrate reduction to ammonium (DNRA) and denitrification. In the second stage, anammox and denitrification were main reactions. In the last stage, anammox was the most important nitrogen loss reaction; nitrogen loss eventually reached a relative balance with the input from sediment mineralization. Based on the data obtained from the last stage, the annual nitrogen loss could be estimated to be about 240-260 Tg in the global OMZs.

Atmospheric wet deposition of dissolved organic carbon to a typical anthropogenic-influenced semi-enclosed bay in the western Yellow Sea, China: Flux, sources and potential ecological environmental effects.

Dissolved Organic Carbon (DOC) is a key organic compound in wet precipitation, but few data are available in China marginal seas. To probe the concentration, deposition flux, seasonality, source and potential ecological environmental effects of precipitation DOC, in this study, one-year precipitation samples were collected at Jiaozhou Bay (JZB), a typical anthropogenic-influenced semi-enclosed bay in the western Yellow Sea for the first time from June 2015 to May 2016. The concentrations of DOC in precipitation were highly variable with a volume-weighted mean (VWM) concentration of 3.63 mg C L-1, which was mostly higher than those in other areas. DOC concentrations were lower in wet season than that in dry season due to the dilution from more amount of rainfall. The wet deposition flux of DOC was calculated to be 3.15 g C m-2 yr-1 with 68.7% of which occurred in wet season mainly owing to the promoting of more rainfall amount. Besides, local emissions together with the long-range transport of pollutants were other factors controlling precipitation DOC. Fossil fuel combustion particularly coal burning was considered to be the leading source of precipitation DOC based on correlation analysis with some generally accepted indicators. Wet deposition dominates the external input of DOC at JZB by comparison with riverine input with a percentage of 54%. Heavy storm may exert enrichment effect on DOC levels in the surface water of JZB, and then promote the secondary productivity. This study emphasizes that wet deposition is an important process that should be seriously considered in the models of global/regional carbon biogeochemical cycling.

Source identification and risk assessment based on fractionation of heavy metals in surface sediments of Jiaozhou Bay, China.

To identify sources and evaluate ecological risks of heavy metals in sediments of Jiaozhou Bay, contents and chemical fractions of Cd, Cr, Cu, Pb, Zn, Ni, Sb and Sn were studied. Results suggested that higher metal contents appeared at inner bay and near marine dumping area. Labile fractions of heavy metals accounted for 0.5-77% (~36%) of total contents indicating their significant anthropogenic sources. The enrichment levels of Cd and Sb were relatively higher. Cu, Ni, Cd and Zn were at low to medium risks. Cr, Pb, Sn and Sb were at no or low risks. Total contents of heavy metals were mainly controlled by natural sources, while anthropogenic inputs were important sources of labile fractions of heavy metals in sediments of Jiaozhou Bay with industrial and domestic activities as main contributors for Cu, Pb, Zn, Cr, Ni and Sn, and agricultural activities for Cd and regional coal combustion for Sb.

Atmospheric wet deposition of dissolved trace elements to Jiaozhou Bay, North China: Fluxes, sources and potential effects on aquatic environments.

To analyze the fluxes, seasonal variations, sources and potential ecological effects of dissolved trace elements (TEs) in atmospheric wet deposition (AWD), one-year wet precipitation samples were collected and determined for nine TEs in Jiaozhou Bay (JZB) between June 2015 and May 2016. Both the volume-weighted mean (VWM) concentration and flux sequence for the measured TEs was Al > Mn > Zn > Fe > Pb > Se > Cr > Cd > Co. Al was the most abundant TE with a VWM concentration and wet flux of 33.8 µg L-1 and 29.2 mg m-2 yr-1, which were 2 and 3 orders of magnitude higher than those of Co, respectively. The emission intensities of pollutants, rainfall amount and wind speed were the dominating factors influencing seasonal variations of TEs in AWD. Based on enrichment factors, correlation analysis and principal component analysis, most of the TEs in AWD were primarily originated from anthropogenic activities except for Al and Fe, which are typically derived from re-suspended soil dusts. Although the TE inputs by AWD were significantly lower than those by rivers, the TE inputs via short-term heavy rains would distinctly increase surface seawater TE concentrations and then pollute the marine environment of JZB. AWD would have both profound impacts on the biogeochemical cycles of TEs and dual ecological effects (nutrient and toxicity) on aquatic organisms.

Fluxes, seasonal patterns and sources of various nutrient species (nitrogen, phosphorus and silicon) in atmospheric wet deposition and their ecological effects on Jiaozhou Bay, North China.

Atmospheric wet deposition (AWD) is an important pathway for anthropogenic and natural pollutants entering aquatic ecosystems. However, the study on the magnitudes and ecological effects of AWD of various nutrient species (nitrogen, phosphorus and silicon) on Jiaozhou Bay is scarce. To address these issues, in this study, wet deposition samples were collected at a coastline site along Jiaozhou Bay from June 2015 to May 2016. Dissolved inorganic nitrogen (DIN, including NH4-N, NO3-N and NO2-N), dissolved organic nitrogen (DON), dissolved inorganic phosphorus (DIP, i.e. PO4-P), dissolved organic phosphorus (DOP) and reactive silicate (SiO3-Si) were analyzed. The volume-weighted mean (VWM) concentrations of NH4-N, NO3-N and DON in AWD were higher compared with those of NO2-N, PO4-P, DOP and SiO3-Si. The annual influxes of NH4-N, NO3-N, NO2-N, DON, DIP, DOP, and SiO3-Si via AWD were 92.8, 54.5, 0.427, 47.5, 0.274, 0.448 and 1.73mmol·m-2·yr-1 respectively; NH4-N and DOP were the dominant species for N and P, and the roles of DON and DOP in AWD could not be neglected. Significant seasonal variations were observed in concentrations and fluxes of all nutrient species owing to the effects of rainfall, the intensities of local emission sources and the long-distance transports of natural and anthropogenic pollutants. The major sources of N, Si and P in AWD were agricultural activities, soil dust and a mixing one involving both anthropogenic and natural sources, respectively. Though AWD represents relatively low percentages of external inputs for nutrients and low contribution to primary productivity (PP) of Jiaozhou Bay, large amounts of nutrient inputs originating from sudden heavy rains may enhance PP prominently, as well as aggravate P-limitation and Si-limitation and further affect phytoplankton community structures and size-fractioned structures with the quite high DIN:DIP ratios and extremely low Si:DIN ratios in AWD.

[Distribution and source of particulate organic carbon and particulate nitrogen in the Yangtze River Estuary in summer 2012].

Based on the data from the cruise carried out in August 2012 in the Yangtze River Estuary and its adjacent waters, spatial distributions of particulate organic carbon (POC), particulate nitrogen (PN) and their relationships with environmental factors were studied, and the source of POC and the contribution of phytoplankton to POC were analyzed combined with n (C)/n (N) ratio and chlorophyll a (Chl a) in the Yangtze River Estuary in summer 2012. The results showed that the concentrations of POC in the Yangtze River Estuary ranged from 0.68 mg x L(-1) to 34.80 mg x L(-1) in summer and the average content was 3.74 mg x L(-1), and PN contents varied between 0.03 mg x L(-1) and 9.13 mg x L(-1) with an average value of 0.57 mg x L(-1). Both of them presented that the concentrations in bottom layers were higher than those in the surface. POC and PN as well as total suspended matter (TSM) showed a extremel similar horizontal distribution trend that the highest values appeared in the near of the mouth and southwest of the survey waters, and decreased rapidly as toward the open seas, both of them showed higher contents in coastal zones and lower in outer sea. There was a fairly good positive linear relationship between POC and PN, which indicated that they had the same source. POC and PN expressed significantly positive correlations with TSM and chemical oxygen demand (COD), but showed relatively weak correlations with salinit and chlorophyll a, which demonstrated that terrestrial inputs had a strong influence on the distribution of POC and PN, and phytoplankton production was not the major source of organic matters in the Yangtze River Estuary. Both the n (C)/n (N) ratio and POC/Chl a analysis showed that the main source of POC was terrestrial inputs, and organic debris was the main existence form of POC. Quantitative analysis showed the biomass of phytoplankton only made an average of 2.54% contribution to POC in the Yangtze Rive Estuary in summer and non-living POC occupied the overwhelming advantage.

High diversity of hepatitis C viral quasispecies is associated with early virological response in patients undergoing antiviral therapy.

UNLABELLED: Differential response patterns to optimal antiviral therapy, peginterferon alpha plus ribavirin, are well documented in patients with chronic hepatitis C virus (HCV) infection. Among many factors that may affect therapeutic efficiency, HCV quasispecies (QS) characteristics have been a major focus of previous studies, yielding conflicting results. To obtain a comprehensive understanding of the role of HCV QS in antiviral therapy, we performed the largest-ever HCV QS analysis in 153 patients infected with HCV genotype 1 strains. A total of 4,314 viral clones spanning hypervarible region 1 were produced from these patients during the first 12 weeks of therapy, followed by detailed genetic analyses. Our data show an exponential distribution pattern of intrapatient QS diversity in this study population in which most patients (63%) had small QS diversity with genetic distance (d) less than 0.2. The group of patients with genetic distance located in the decay region (d>0.53) had a significantly higher early virologic response (EVR) rate (89.5%), which contributed substantially to the overall association between EVR and increased baseline QS diversity. In addition, EVR was linked to a clustered evolutionary pattern in terms of QS dynamic changes. CONCLUSION: EVR is associated with elevated HCV QS diversity and complexity, especially in patients with significantly higher HCV genetic heterogeneity.