Spatial and temporal distribution patterns of nitrogen in marsh soils from an inland alkaline wetland – A case study of Fulaowenpao wetland, China

Samples of surface (0–10 cm) and subsurface soils (10–20 cm) were collected using a grid sampling method in July and September in order to study the spatial and temporal distribution patterns of all forms of nitrogen and total nitrogen (TN) and the relationships between nitrogen concentrations and selected soil properties in Fulaowenpao wetland, a typical inland alkaline wetland. Results showed that there existed obvious heterogeneity at spatial and temporal scales. Generally, higher spatial variability for nitrate nitrogen (NO₃^-–N), ammonium nitrogen (NH₄⁺–N) and available nitrogen (AN) were observed compared to organic nitrogen (Org-N) and TN. At the spatial scale, concentrations of NO₃^-–N, NH₄⁺–N and AN in surface soils were higher than those in subsurface soils, but no significant differences were observed between both soil layers (p < 0.05). However, concentrations of Org-N and TN were significantly higher in surface soils compared to subsurface soils (p < 0.05), and both of them had similar spatial distribution patterns. At the temporal scale, with the exception of NH₄⁺–N in both soil layers and NO₃^-–N in subsurface soils, concentrations of all the other forms of nitrogen and TN were generally higher in September than them in July, while there were no significant differences between both sampling periods (p < 0.05) except for AN (p < 0.01) in both soil layers. Correlation analysis showed that AN, Org-N and TN were significantly and positively correlated with soil organic matter, total phosphorous, and clay contents, while they were significantly negatively correlated with soil pH values; NO₃^-–N was also correlated with soil organic matter and total phosphorous, however, NH₄⁺–N was only closely lined to water contents.     

Anaerobic digestion of starch-polyvinyl alcohol biopolymer packaging: biodegradability and environmental impact assessment

The digestibility of a starch-polyvinyl alcohol (PVOH) biopolymer insulated cardboard coolbox was investigated under a defined anaerobic digestion (AD) system with key parameters characterized. Laboratory results were combined with industrial operational data to develop a site-specific life cycle assessment (LCA) model. Inoculated with active bacterial trophic groups, the anaerobic biodegradability of three starch-PVOH biopolymers achieved 58-62%. The LCA modeling showed that the environmental burdens of the starch-PVOH biopolymer packaging under AD conditions on acidification, eutrophication, global warming and photochemical oxidation potential were dominated by atmospheric emissions released from substrate degradation and fuel combustion, whereas energy consumption and infrastructure requirements were the causes of abiotic depletion, ozone depletion and toxic impacts. Nevertheless, for this bio-packaging, AD of the starch-PVOH biopolymer combined with recycling of the cardboard emerged as the environmentally superior option and optimization of the energy utilization system could bring further environmental benefits to the AD process.     

乙型肝炎病毒HBx蛋白抑制TTRAP启动子活性的体外研究

旨在探讨体外培养条件下HBx蛋白对TTRAP(TRAF and TNF receptor-associated protein)基因转录水平表达的影响。用RT-PCR及Real-time PCR检测TTRAP在HepG2细胞和HepG2.2.15细胞中的表达;构建TTRAP启动子虫荧光素酶报告质粒;分别与HBV、HBs、HBp、HBc、HBx表达质粒共转染HepG2细胞,比较虫荧光素酶活性。RT-PCR和Real-time PCR结果显示,TTRAP在HepG2.2.15细胞中的表达量分别是其在HepG2细胞中表达量的44.9%和27.8%(P0.05)。TTRAP启动子虫荧光素酶报告质粒与HBV表达质粒共转染组的相对荧光素酶活性,与对照组相比下降了43.8%。转染HBx表达质粒组的相对荧光素酶活性与其对照组相比下降了35%,而转染HBc、HBs及HBp表达质粒组对相对荧光素酶活性没有影响。因此证实HBx蛋白能抑制TTRAP启动子活性。     

Comparative computational RNA analysis of cardiac-derived progenitor cells and their extracellular vesicles

Stem/progenitor cells, including cardiac-derived c-kit+ progenitor cells (CPCs), are under clinical evaluation for treatment of cardiac disease. Therapeutic efficacy of cardiac cell therapy can be attributed to paracrine signaling and the release of extracellular vesicles (EVs) carrying diverse cargo molecules. Despite some successes and demonstrated safety, large variation in cell populations and preclinical/clinical outcomes remains a problem. Here, we investigated this variability by sequencing coding and non-coding RNAs of CPCs and CPC-EVs from 30 congenital heart disease patients and used machine learning methods to determine potential mechanistic insights. CPCs retained RNAs related to extracellular matrix organization and exported RNAs related to various signaling pathways to CPC-EVs. CPC-EVs are enriched in miRNA clusters related to cell proliferation and angiogenesis. With network analyses, we identified differences in non-coding RNAs which give insight into age-dependent functionality of CPCs. By taking a quantitative computational approach, we aimed to uncover sources of CPC cell therapy variability.     

Efficiency of two-stage combinations of subsurface vertical down-flow and up-flow constructed wetland systems for treating variation in influent C/N ratios of domestic wastewater

The performance and temporal variation of four hybrid, intermittent loading, pilot-scale vertical flow constructed wetlands (VFCWs) were tested for treating domestic wastewater of three different C/N ratios (2.5:1, 5:1, and 10:1, respectively). Two hybrid systems each consisted of the two identical VFCWs in-series, with up-up or down-down flow. The other two hybrid systems consisted of the first VFCWs (up or down flow) followed by a second VFCWs (down or up flow, respectively). The effects of combination mode, season, load level, and interactions on nutrient removal were studied in synthetic wastewater in the two-stage VFCW systems. With varying C/N ratios for influent water (from 2.5:1, 5:1 to 10:1) average removal efficiencies for the two-bed two-stage systems were as follows: COD 73-93%, TN 46-87%, TP 75-90%, and TOC 40-66%, respectively. All two-bed hybrid VFCWs were efficient in removing organics and total phosphorus, and reached the highest removal rates when the C/N ratios were 10 and 5, respectively. The hybrid systems for different flow direction beds had significantly higher performance (P < 0.05) during the wetlands operational period. Compared to the four types of hybrid VFCWs, the two-stage combination with different flow directions achieved significantly higher TN and TOC reductions (P < 0.05). The highest total nitrogen (P < 0.05) and total phosphorus reductions in down-up flow VFCWs were observed at C/N 5:1. However, for organic matter and total organic carbon, the highest COD and TOC removal rates occurred when C/N ratios were 5-10 for the down-up flow VFCWs. With appropriate control of combined mechanisms in series, the concentrations of carbon and nitrogen sources in the influent can achieve the optimal effects of nutrient removal.     

Organic nitrogen exports from urban stormwater wetlands in North Carolina

Effluent organic nitrogen concentrations from seven constructed stormwater wetlands in North Carolina were examined to compare background organic nitrogen (ON) concentrations and the fraction of organic nitrogen relative to total nitrogen discharged. Seasonal influences on organic nitrogen concentrations were also examined. The median ON concentration from the stormwater wetlands was 0.78 mg l⁻¹, and despite differences in wetland design and influent ON characteristics, outlet ON concentrations from all but one wetland were not significantly different. ON export from all stormwater wetlands was significantly less than untreated runoff entering the wetlands (p = 0.002). In addition, median organic:total nitrogen (ON:TN) ratios from stormwater wetlands (0.75) were significantly greater than from untreated urban runoff (0.66), comparing more closely to ON:TN ratios collected from a naturally occurring wetland and reported in the literature for natural landscapes. Seasonal differences in organic nitrogen concentrations were identified with significantly lower concentrations during the winter. Though stormwater wetlands will not (and perhaps should not be expected to) completely remove total nitrogen loads from runoff, these results suggest constructed wetlands can play a role in restoring the balance between organic and inorganic nitrogen forms closer to that of an undisturbed landscape. The presence of background organic nitrogen concentrations from stormwater wetlands similar to those from a naturally occurring wetland highlights the importance of choosing appropriate metrics (e.g., effluent concentrations) when assessing treatment performance.     

Effects of pesticides on division of two lepidopteran cell lines and onAutographa Californica MNPV development in TN368 cells

Summary The concentration of each of 10 pesticides (azinphosmethyl, captan, carbaryl, chlordimedorm, dichlorvos, dimenthoate, fenvalerate, methomyl, methyl parathion, trichlorfon) causing a 50% inhibition (ID₅₀) in cell number relative to an untreated culture for a time period equal to four cell doublings was determined for the TN368 and IPLB-HZ1075 cell lines. The range of ID₅₀ values with either of the cell lines was similar, with captan being most toxic within an ID₅₀ range of 5 to 6 μM/2×10⁵ cells/ml, and methomyl least toxic within a range of 2900 to 3200 μM/2×10⁵ cells/ml. Yet there were significant differences between cell lines in pesticide susceptibility. Fenvalerate, dichlorvos, and chlordimeform were 16, 3, and 1.5 times more toxic, respectively, for TN368 cells than HZ1075 cells, whereas dimethoate and carbaryl were each 2 times more toxic for HZ1075 cells. In general, increasing toxicity paralleled decreasing water solubility, although the order of the pesticides varied somewhat according to the particular cell line and medium. Moreover, there was little aberrant cell morphology in either of the cell cultures during incubation with most of the pesticides at their ID₅₀ levels. Preincubation of TN368 cells with any one of seven different pesticideis before inoculation withAutographa californica MNPV, and subsequent incubation of infected cells in medium plus pesticide, did not significantly suppress polyhedra development except for trichlorfon-incubated cells. In addition, there was a small but consistent variation from control cells in extracellular virus titers assayed from two of five of the pesticide incubations. The titer was consistently depressed with trichlorfon and elevated with fenvalerate, however, further work is required to determine the biological significance of these differences. Primary funding for this research was provided by the Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC, under grant no. R-809453. Additional funding was provided by the Pennsylvania State University College of Agriculture Experiment Station—Project no. 2758. The contents of this publication do not necessarily reflect the views, policies, or recommendations of the Environmental Protection Agency, and the Agency does not necessarily endorse any of the commercial products used in this study. The Pennsylvania State Agricultural Experiment Station. Authorized for publication as Journal Series Paper No. 7432.     

Does aging affect the intestinal transport of riboflavin?

Riboflavin deficiency has been reported in older individuals. The cause of this deficiency is not know but could include a decrease in the intestinal absorptive capacity for riboflavin. Therefore, we examined the intestinal absorption of riboflavin in young (3 month) and old (26 month) rats. We used in vitro jejunal everted sacs. The kinetic parameters of riboflavin absorption disclosed apparent Km of 0.37 and 0.43 microM and Vmax of 37 and 38 pmole/g initial tissue wet wt/20 min in young and old rats, respectively. These data do not demonstrate an aging associated change in the intestinal transport capacity for riboflavin. If these results are extrapolated to man, it would mean that the deficiency of riboflavin found in the elderly is not due to its intestinal malabsorption. Therefore, other mechanisms must be sought to account for the deficiency of riboflavin seen in the elderly.