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91.
Peng C Chan HY Huang Y Yu H Chen ZY 《Journal of agricultural and food chemistry》2011,59(5):2097-2106
Apple polyphenols (AP) are an excellent source of dietary antioxidants. The present study investigated the effect of AP on the lifespan of fruit flies and their interaction with gene expressions of superoxide dismutase (SOD), catalase (CAT), methuselah (MTH), Rpn11, and cytochrome c oxidase (CcO) subunits III and VIb. Results showed the mean lifespan was significantly extended by 10% in fruit flies fed the AP diet. This was accompanied by up-regulation of genes SOD1, SOD2, and CAT and down-regulation of MTH in the aged fruit flies. Paraquat and H(2)O(2) challenge tests demonstrated that AP prolonged the survival time only for Oregon R wild type flies but not for SOD(n108) or Cat(n1) mutants, in which either SOD or CAT was knocked out. Chronic paraquat exposure could shorten the maximum lifespan from 68 to 31 days and reduce the climbing ability by 60%, whereas AP could partially reverse the paraquat-induced mortality and decline in climbing ability. AP could up-regulate Rpn11 at day 30, whereas it appeared to have no significant effect on gene expression of ubiquitinated protein, CcO subunits III and VIb. These AP-induced changes were unlikely associated with caloric restriction as the gustatory assay found no difference in average body weight and stomach redness index between the control and AP fruit flies. It was therefore concluded that the antiaging activity of AP was, at least in part, mediated by its interaction with genes SOD, CAT, MTH, and Rpn11. 相似文献
92.
Hwang PA Chien SY Chan YL Lu MK Wu CH Kong ZL Wu CJ 《Journal of agricultural and food chemistry》2011,59(5):2062-2068
Sargassum hemiphyllum , a kind of brown seaweed generally found along coastlines in East Asia, has long served as a traditional Chinese medicine. S. hemiphyllum has shown an anti-inflammatory effect; however, its mechanism has not been elucidated clearly. This study explored S. hemiphyllum for its biomedical effects. S. hemiphyllum sulfated polysaccharide extract (SHSP) was first prepared; the mouse macrophage cell line (RAW 264.7) activated by lipopolysaccharide (LPS) was used as a model system. The secretion profiles of pro-inflammatory cytokines, including IL-1β, IL-6, TNF-α, and NO, were found significantly to be reduced in 1-5 mg/mL dose ranges of SHSP treatments. RT-PCR analysis suggested SHSP inhibits the LPS-induced mRNA expressions of IL-β, iNOS, and COX-2 in a dose-dependent manner. At protein levels, Western blot analysis demonstrated a similar result for NF-κB (p65) in cytosol/nuclear. Taken together, the anti-inflammatory properties of SHSP may be attributed to the down-regulation of NF-κB in nucleus. 相似文献
93.
Sarah J. Converse Kevin J. Shelley Steve Morey Jeffrey Chan Andrea LaTier Carolyn Scafidi Deborah T. Crouse Michael C. Runge 《Biological conservation》2011,(1):319-329
The resources available to support conservation work, whether time or money, are limited. Decision makers need methods to help them identify the optimal allocation of limited resources to meet conservation goals, and decision analysis is uniquely suited to assist with the development of such methods. In recent years, a number of case studies have been described that examine optimal conservation decisions under fiscal constraints; here we develop methods to look at other types of constraints, including limited staff and regulatory deadlines. In the US, Section Seven consultation, an important component of protection under the federal Endangered Species Act, requires that federal agencies overseeing projects consult with federal biologists to avoid jeopardizing species. A benefit of consultation is negotiation of project modifications that lessen impacts on species, so staff time allocated to consultation supports conservation. However, some offices have experienced declining staff, potentially reducing the efficacy of consultation. This is true of the US Fish and Wildlife Service’s Washington Fish and Wildlife Office (WFWO) and its consultation work on federally-threatened bull trout (Salvelinus confluentus). To improve effectiveness, WFWO managers needed a tool to help allocate this work to maximize conservation benefits. We used a decision-analytic approach to score projects based on the value of staff time investment, and then identified an optimal decision rule for how scored projects would be allocated across bins, where projects in different bins received different time investments. We found that, given current staff, the optimal decision rule placed 80% of informal consultations (those where expected effects are beneficial, insignificant, or discountable) in a short bin where they would be completed without negotiating changes. The remaining 20% would be placed in a long bin, warranting an investment of seven days, including time for negotiation. For formal consultations (those where expected effects are significant), 82% of projects would be placed in a long bin, with an average time investment of 15 days. The WFWO is using this decision-support tool to help allocate staff time. Because workload allocation decisions are iterative, we describe a monitoring plan designed to increase the tool’s efficacy over time. This work has general application beyond Section Seven consultation, in that it provides a framework for efficient investment of staff time in conservation when such time is limited and when regulatory deadlines prevent an unconstrained approach. 相似文献
94.
Relationship between soil structure and runoff/soil loss after 24 years of conservation tillage 总被引:6,自引:1,他引:6
A better understanding of tillage and stubble management effects on surface soil structure is vital for the development of effective soil conservation practices for the long-term. Relationships between aspects of soil structure and runoff/soil loss were investigated in 24 year old field experiment on an Oxic Paleustalf, in NSW, Australia. Two tillage/stubble management systems were compared, namely direct drilled/stubble retained (DD/SR) versus conventional tillage/stubble burnt (CC/SB). Tillage and stubble burning significantly increased bulk density and decreased the macro-aggregate stability, mean weight diameter (MWD), geometric mean diameter (GMD) and total porosity, particularly macroporosity (>60 μm). For the 0–5 cm layer, DD/SR had significantly higher water stability of macro-aggregates >2 mm than CC/SB (165 g/kg versus 78 g/kg), and the volume of pore space of diameter >60 μm at 0–5 cm depth was significantly greater (more than 11%) for DD/SR than for CC/SB. Under simulated rainfall (100 mm/h) and the removal of surface stubble, both runoff and soil loss were significantly higher under CC/SB compared to DD/SR. The infiltration rate at the end of the experiment under DD/SR was 3.7 times that of CC/SB (85 mm/h versus 23 mm/h). There were significant correlations between the proportion of soil particles >0.25 mm measured after wetting by rain and both final infiltration rate (P < 0.001) and soil loss (P < 0.001). It was concluded that 24 years of direct drilling and stubble retained practices significantly reduced runoff and soil erosion hazards, due to a fundamental change in soil structure, viz. higher soil aggregate stability and higher macroporosity of the surface soil. 相似文献
95.
96.
Wang J Chan WG Haut SA Krauss MR Izac RR Hempfling WP 《Journal of agricultural and food chemistry》2005,53(12):4686-4691
A method for the determination of total N-nitroso compounds (NOC) by chemical denitrosation and subsequent chemiluminescence detection of evolved NO is described. Denitrosation was accomplished with CuCl in HCl at 70 degrees C. The detection limit for N-nitrosoproline (NPRO) was 1 pmol. NO formation from NPRO was linear (R(2) = 0.999) from 4 pmol to 2 nmol. Among the possible interfering compounds tested, only S-nitroso compounds contribute any significant interference. This method had several advantages over other similar methods: (1) A commercially available one-piece reaction vessel and a NO analyzer with software were used. (2) NO release occurred rapidly and was easily measured and quantified. (3) Compared to HBr or HI, CuCl was more convenient to work with and safe. (4) CuCl was suitable for samples in aqueous and most organic solvents. The application of this method to food, personal care products, and human body fluids demonstrates its utility. 相似文献
97.
Kinetics of H+ consumption by mineral dissolution in a surface soil and a subsoil of an acid woodland soil were studied by means of batch type experiments and stationary pH titrations. Mineral dissolution in the subsoil could effectively be described by congruent dissolution of illite (K0.6Mg0.25A12.3S13010(OH)2) followed by an incongruent dissolution stage. In the incongruent stage the concentration of Al decreased while concentrations of K and Mg continued to increase. Congruent dissolution rates of illite could be predicted with power type relationships from transition state theory. In the incongruent dissolution stage the activities of H and Al appeared to be controlled by precipitation of A1(OH)3. Results of this kind of experiments could be helpful to understand the behavior of Al and base cations in acid soils and soils with high atmospheric loadings of acid. Comparison of the results of batch experiments for a surface soil and a subsoil showed that initially proton consumption in the surface soil is faster and more effective due to the presence of a relatively high cation exchange capacity and base saturation value. However with progressive proton consumption and increasing reaction times proton consumption in the subsoil becomes faster than in the surface soil, presumably due to higher rates of mineral dissolution in the subsoil. Lower dissolution rates in the surface soil may result from lower contents of easily weatherable minerals, due to excessive leaching in the past which is reflected in a 17% lower acid neutralizing capacity than in the subsoil. 相似文献
98.
Simple automated wet digestion of animal tissues for determination of seven elements by atomic absorption spectroscopy 总被引:2,自引:0,他引:2
A simple, automated wet digestion procedure was developed for the quantitative determination by atomic absorption spectroscopy (AAS) of arsenic, cadmium, copper, mercury, lead, selenium, and zinc in animal tissue. A commercial digestion block system with automated temperature programming was used. Recoveries of all elements from spiked bovine liver and kidney samples exceed 95%. The analytical results obtained for samples of NBS Bovine Liver (No. 1577a) agree well with certified values. The procedure is safe and requires minimum analyst time. 相似文献
99.
100.
Walter H. Chan Al J. S. Tang David H. S. Chung Maris A. Lusis 《Water, air, and soil pollution》1986,29(4):373-389
Results of trace metal concentrations in air and precipitation and the corresponding wet and dry deposition in Ontario in 1982 arc reported. In terms of the spatial patterns, in general, there was a decreasing gradient from south-to-north in both concentration and deposition. Patterns differed with each parameter although certain groups of metals (e.g., Fe and Al; Pb, Zn, and Mn) displayed similar patterns. In general, wet deposition was greater than dry deposition at all sites. Geographically, the variability in the wet to dry deposition ratio for coarse particles (MMD > 2.5 μm) was small. However, it increased from the south to the north for fine particles (MMD < 2.5 μm), being higher away from the source areas. Scavenging ratios (W) have been derived from the precipitation and air concentrations of trace metals. The scatter in W is quite large for all trace metals, up to 2 orders of magnitude. There was little seasonal variability in W for fine particles (Pb, Mn, Zn, and Cd). However, coarse particles (Fe, Al, and Cu) were more efficiently scavenged by snow than by rain. 相似文献