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1.
Targeted therapies, such as agents that inhibit angiogenesis, offer hope as complementary agents in cancer therapy. Angiogenesis-inhibiting agents have the potential for inhibiting tumor growth and limiting the dissemination of metastasis, thus keeping cancers in a static growth state for prolonged periods. Black raspberry (Rubus occidentalis) extract was discovered to be antiangiogenic (0.1% w/v) in a novel human tissue-based in vitro fibrin clot angiogenesis assay. Assay-guided fractionation of a crude black raspberry extract resulted in a highly potent antiangiogenic fraction that accounted for only 1% of the fresh weight of whole black raspberries. At 0.075% (w/v), the active fraction completely inhibited angiogenic initiation and angiogenic vessel growth. Further subfractionation of this active fraction revealed the coexistence of multiple antiangiogenic compounds, one of which has been identified as gallic acid. However, the individual subfractions did not outperform the active whole fraction. These findings suggest that an active black raspberry fraction may be a promising complementary cancer therapy. It is natural and potent enough for manageable dosing regimens. These extracts contain multiple active ingredients that may be additive or synergistic in their antiangiogenic effects. These observations warrant further investigations in animals and human trials.  相似文献   

2.
五氯酚在长期定位施肥土壤中的残留动态   总被引:1,自引:1,他引:0  
王诗生  卞永荣  王芳  杨兴伦  李忠佩  蒋新 《土壤》2009,41(3):442-447
研究好氧和厌氧条件下五氯酚 (PCP) 在长期不施肥 (CK),施无机肥尿素 (N),施有机肥 (OM)和无机有机肥配施 (N+OM) 4 种处理土壤中的残留动态.结果表明,无论在好氧或厌氧条件下,PCP 在土壤中的消解均遵循一级动力学方程.在好氧条件下,PCP 在 CK、N、OM 和 N+OM 4 种处理土壤中半衰期分别为 26.9、27.7、21.5、20.6 天,在厌氧条件下,PCP 的半衰期分别为 30.8、32.2、27.1、25.9 天.表明无论在好氧或厌氧条件下,长期单施有机肥或无机有机肥配施显著加速 PCP 在土壤中的消解,原因可能是长期单施有机肥或无机有机肥配施能显著提高土壤有机质含量和微生物活性,加速 PCP 在土壤中的消解.好氧条件下 PCP 的消解速率显著高于厌氧条件.  相似文献   

3.
水稻土和菜田添加碳氮后的气态产物排放动态   总被引:1,自引:0,他引:1  
【目的】动态连续监测添加碳氮底物后各气体产物—O2、 NO、 N2O、 CH4和N2的排放,对土壤碳氮转化过程和气体产生过程做更深入的理解,揭示不同土地利用方式典型红壤的温室气体产生机制。【方法】采集长江中游金井小流域不同土地利用方式稻田和菜地土壤为研究对象,利用全自动连续在线培养检测体系(Robot系统),通过两组试验分别研究土壤碳氮转化过程中各气体产物的动态变化。试验1采用菜地和稻田土壤进行好气培养,设置不施氮对照、 添加40 mg/kg铵态氮、 添加40 mg/kg铵态氮+1%硝化抑制剂、 添加40 mg/kg硝态氮、 添加40 mg/kg硝态氮+1%葡萄糖、 缺氧条件下添加40 mg/kg硝态氮+1%葡萄糖6个处理。试验2采用稻田土壤进行淹水培养,设不施氮对照、 添加40 mg/kg铵态氮、 添加40 mg/kg铵态氮+1%硝化抑制剂、 添加40 mg/kg铵态氮+1%秸秆、 缺氧条件下添加40 mg/kg铵态氮+1%的葡萄糖、 添加40 mg/kg硝态氮、 添加40 mg/kg硝态氮+1%葡萄糖、 缺氧条件下添加40 mg/kg硝态氮+1%葡萄糖8个处理。培养温度均为20℃,土壤水分含量为70% WFPS (土壤孔隙含水量),培养周期为15天。【结果】从菜地和稻田土壤不同碳氮添加处理气态产物及无机氮的动态变化可看出: 1)菜地土壤好气培养初期硝化作用产生了大量N2O; 受低碳和低含水量的限制,反硝化作用较弱。当提供充足碳源和厌氧条件,出现N2O和NO的大量排放。2)在好气稻田和淹水稻田培养过程中,反硝化作用是N2O产生的主要途径。3)稻田土壤中,提供充足碳源和厌氧条件,各气态产物出现的顺序依次是NO、 N2O和N2,与三种气体在反硝化链式反应过程中的生成顺序一致。淹水稻田加铵态氮和碳源处理N2为主要产物,添加硝态氮处理后,N2O成为主要气态产物。当土壤碳源充足时,反硝化过程进行彻底,反硝化产物以终产物(N2)为主。4)在稻田土壤出现厌氧或添加碳源条件下,均检测到大量CH4产生; 且在甲烷产生的同时,NO-3几乎消耗殆尽。【结论】金井小流域典型红壤菜地N2O主要来自于硝化作用,好气和淹水稻田N2O主要来源于反硝化作用; 当碳源充足和厌氧时,菜地及稻田反硝化作用增强; 反硝化产物组成、 产物累积量及出峰顺序与碳源和氧气浓度有关。  相似文献   

4.
Three triterpenic acids, oleanolic acid, ursolic acid and maslinic acid, at 2 or 4 μmol/L were used to study their antiangiogenic potential in human liver cancer Hep3B, Huh7 and HA22T cell lines. The effects of these compounds upon the level and/or expression of hypoxia-inducible factor (HIF)-1α, basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), interleukin (IL)-8, urokinase plasminogen activator (uPA), reactive oxygen species (ROS), nitric oxide (NO) and cell invasion and migration were examined. Results showed that these triterpenic acids at 4 μmol/L significantly suppressed HIF-1α expression in three cell lines (P < 0.05); and these compounds at test doses failed to affect bFGF expression (P > 0.05). Three triterpenic acids dose-dependently decreased production and expression of VEGF and IL-8, retained glutathione level, lowered ROS and NO levels, and declined cell invasion and migration in test cell lines (P < 0.05). These compounds also dose-dependently reduced uPA production and expression in Hep3B and Huh7 cell lines (P < 0.05); but these agents only at 4 μmol/L significantly suppressed uPA production and expression in HA22T cells (P < 0.05). These findings suggest that these triterpenic acids are potent antiangiogenic agents to retard invasion and migration in liver cancer cells.  相似文献   

5.
The effect of soil aeration status on carbon partitioning of a labelled organic substrate (14C-[U]-glucose) into CO2, microbial biomass, and extra-cellular metabolites is described. The soil was incubated in a continuous flow incubation apparatus under four different aeration conditions: (1) permanently aerobic, (2) permanently anaerobic, (3) shifted from anaerobic to aerobic, and (4) shifted from aerobic to anaerobic. The soil was pre-incubated for 10 days either under aerobic or under anaerobic conditions. Afterwards, glucose was added (315 g C g–1) and the soils were incubated for 72 h according to four treatments: aerobic or anaerobic conditions maintained, aerobic conditions shifted to anaerobic conditions and anaerobic conditions shifted to aerobic conditions. Carbon partitioning was measured 0, 8, 16, 24, 48 and 72 h after the glucose addition. In permanently aerobic conditions, the largest part of the consumed glucose was built into microbial biomass (72%), much less was mineralised to CO2 (27%), and only a negligible portion was transformed to soluble extra-cellular metabolites. Microbial metabolism was strongly inhibited when aeration conditions were changed from aerobic to anaerobic, with only about 35% of the added glucose consumed during the incubation. The consumed glucose was transformed proportionally to microbial biomass and CO2. In permanently anaerobic conditions, 42% of the consumed glucose was transformed into microbial biomass, 30% to CO2, and 28% to extra-cellular metabolites. After a shift of anaerobic to aerobic conditions, microbial metabolism was not suppressed and the consumed glucose was transformed mainly to microbial biomass (75%) and CO2 (23%). Concomitant mineralisation of soil organic carbon was always lower in anaerobic than in aerobic conditions.  相似文献   

6.
在实验室条件下,采用混合均匀的Alafia河表层沉积物并以蒸馏水为上覆水进行沉积物磷释放模拟试验,研究了溶解氧、有机碳和金属铝对沉积物磷(PO4-P)释放的影响。结果表明,试验期间厌氧条件下沉积物磷释放量明显高于好氧条件下。厌氧条件下,未添加金属铝、添加有机碳源的试验组中沉积物释放平衡时水中磷浓度为5.93mg.L-1;好氧条件下,平衡时水中磷浓度为2.39mg.L-1。研究还发现,未添加金属铝的试验组,无论好氧还是厌氧条件下,未添加有机碳源时,沉积物磷释放量高于添加碳源条件;而在添加金属铝后,添加有机碳源的试验组中磷释放量略高于未添加碳源的试验组。添加金属铝能够明显抑制沉积物中磷的释放。未添加金属铝,厌氧条件下,平衡时水中磷浓度为6.91mg.L-1,好氧条件下,释放平衡时水中磷浓度为3.70mg.L-1;而添加金属铝的试验组,无论厌氧还是好氧条件下,上覆水中磷浓度均很小,接近于0mg.L-1。  相似文献   

7.
Stimulation of gamma-aminobutyric acid (GABA) production under low O2 and high CO2 conditions (adjusted aerobic atmosphere) under which ethanol fermentation could be avoided was studied. Vine-ripe tomato fruits were stored under hypoxia conditions and adjusted aerobic atmospheres as well as in the air at 15 degrees C for 13 days and at 30 degrees C for 6 days. At 30 degrees C tomato fruit GABA concentration under the adjusted aerobic atmosphere (O2 11%, CO2 9%) was significantly higher by 48% than that in air after 6 days from the start of storage. Increased accumulation of alanine under the adjusted aerobic atmosphere supports the observation that this atmosphere stimulates GABA production. The results demonstrate that the concentration of GABA as a beneficial substance for antihypertensive effects and so on can be increased by storing tomato fruits under adjusted aerobic atmospheres for the first time.  相似文献   

8.
Microbial mineralization rates of a 14C-labelled PCB mixture were determined in PCB-contaminated Capitol Lake, LA, sediment under controlled pH and redox conditions. Mineralization rates were inferred from the activity of 14CO2 evolved from the sediment suspensions. Sediment pH and redox potential significantly affected PCB mineralization. Mineralization rates were higher under moderately aerobic conditions (microaerophilic) ( + 250 mV) than under aerobic conditions ( + 500 mV) or anaerobic conditions (0 mV and ?200 mV). PCB mineralization rates in moderately aerobic sediment were 30 to 40 fold higher than those in anaerobic sediment. Sediment conditions in the oxidized surface layer would promote PCB mineralization. Sediment pH and redox potential were shown to be two sediment parameters which can be managed to enhance degradation of PCBs in contaminated sediment.  相似文献   

9.
水体沉积物界面中磷的释放机制非常复杂,生物作用导致的pH值和氧化还原条件变化对湖泊沉积物矿化能力有显著影响。普遍认为沉积物中有机磷的矿化过程是对水体富营养化具有重要贡献的环节之一,而核酸态有机磷可从一定程度上表征微生物水平,反应微生物对矿化作用的影响。据此采用DNA提取的方法对沉积物中核酸态有机磷的含量进行测定,并模拟沉积物中核酸在不同pH和溶解氧条件下的矿化过程。结果表明,DNA提取方法可以快速、准确提取沉积物中核酸磷;沉积物中核酸磷含量为0.43~0.61μg·g^-1,占有机磷总量的0.27%~0.37%,精确度为1.58%~3.63%。模拟实验结果表明,在两种情况下上覆水中总磷浓度均呈波动式上升,在pH接近7时沉积物中核酸磷较低,有氧条件下核酸磷呈下降趋势。  相似文献   

10.
ABSTRACT

Methane is a greenhouse gas, mainly generated from paddy fields and lakes by methanogens using hydrogen and acetic acid as substrates. In anaerobic environments with adequate Fe3+, iron-reducing microorganisms utilize these substrates, thus suppressing methane generation. We promoted Fe2+ oxidation to Fe3+ by physically stirring paddy soil and using a chelating agent (nitrilotriacetic acid; NTA) to evaluate the feasibility of the suppression of methane generation using Fe3+-reducing bacteria. Under anaerobic conditions, Fe3+ reduction to Fe2+ began immediately in the slurry made by adding water into air-dried paddy soil. Methane generation began on the 6th day when most Fe3+ was reduced. Under anaerobic conditions for 10 days followed by aerobic conditions, Fe2+ oxidation hardly progressed under static conditions. On stirring the slurry, Fe2+ oxidation progressed over 12 h (67% Fe2+ oxidized to Fe3+). When NTA was added under anaerobic conditions followed by stirring under aerobic conditions, Fe2+ oxidation was promoted further. The idea of physical stirring of paddy soil in the actual environment was derived from the effects of paddy soil stirring by ducks in interrelated rice–duck farming. In such farming, paddy soil contains more Fe3+ in its surface water compared with normal farming, resulting in suppressed methane generation.  相似文献   

11.
The microbiological degradation of a mixture of alkylpyridines in groundwater maintained under aerobic and anaerobic conditions was examined. A marked difference was observed between the aerobic and anaerobic degradation rates. In the presence of a soil inoculum and under aerobic conditions, the residual alkylpyridine concentrations generally approached zero concentration within 10 to 31 days of incubation, whereas under anaerobic conditions the concentrations of residual alkylpyridines only decreased between 40 and 80% over a 33 day incubation period. Biodegradation rates under aerobic conditions were greatly affected by the specific ring substitution of structural isomers within a given weight class. A similar effect was not observed for anaerobic degradation rates.  相似文献   

12.
Two horizontal constructed wetlands with subsurface flow (CWs) of different age were monitored in a 2-year study. One of the CWs was new, while the second one had been in operation for 5 years in the first year of study. Transformations of C, P, and N were measured in each CW in the substrate of the vegetated bed under both aerobic and anaerobic conditions, and their rates were compared. C was mineralized in both CWs under both aerobic and anaerobic conditions, but mineralization rates differed between the CWs; they were cca ten times higher in the established CW compared to the new CW. Dissolved reactive phosphorus (DRP) was immobilized under aerobic conditions but was mobilized under anaerobic conditions. DRP transformation was cca five times faster in the established CW. Nitrification occurred under aerobic conditions at similar rates in both CWs. NH4 + concentration decreased under both aerobic and anaerobic conditions, but there was large variability. The age of the CW affected C mineralization rates and DRP immobilization rates under aerobic conditions and mobilization rates under anaerobic conditions; they increased as the CWs maturated, while no effect of CW age was observed on nitrogen removal rates.  相似文献   

13.
Summary The hydrolysis of fertilizer-grade solid and liquid ammonium polyphosphate (APP) was studied on an aluvial (Entisol, Typic Ustifluvent), a sodic (Entisol Aquic Ustifluvent), and a laterite (Oxisol, Aquox) soil under aerobic and anaerobic conditions. The hydrolysis rate was the fastest on laterite, intermediate on sodic, and slowest in the alluvial soil. Ammonium polyphosphate hydrolyzed more rapidly under anaerobic than under aerobic conditions. The hydrolysis of liquid ammonium polyphospahte was faster than that of solid ammonium polyphosphate in all soils. The half-life values for the polyforms of P in liquid ammonium polyphosphate ranged from 1.6 to 2.0 days under anaerobic and from 5.2 to 8.7 days under aerobic conditions. The corresponding values for solid ammonium polyphosphate were 3.9 to 9.2 days under anaerobic and 12.5 to 27.0 days under aerobic conditions.  相似文献   

14.
Laboratory studies on a sandy clay loam (Typic Ustochrept) alkaline soil showed that NH3 volatilization loss from surface-applied prilled urea during an 8-dya incubation under aerobic conditions was 27.5% of applied N (400 kg N ha-1) and was reduced to 8.9% when the urea was blended physically with pyrite in a 1:2 ratio; under anaerobic conditions the values for urea and pyrite-urea were 19.3 and 16.9%, respectively. Other treatments tested were urea-gypsum, neemcake-coated urea and polymer-coated urea. A 6% polymer coating showed the least NH3 volatilization under anaerobic conditions and was next best to pyrite-urea under aerobic conditions. A 3% polymer coating was slightly inferior to the 6% coating. Urea-gypsum and neemcake-coated urea did not differ very much from urea alone under anaerobic conditions, but under aerobic conditions neemcake-urea showed a significantly lower total NH3 loss compared to prilled urea alone and urea-gypsum.  相似文献   

15.
Biological degradation rates of estrogen compounds and common pharmaceutical and personal care products (PPCPs) were examined in soils with a long history of exposure to these compounds through wastewater effluent and in soil not previously exposed. Biological degradation rates over 14 days were compared under aerobic and anaerobic conditions. Estrogen compounds including estrone, 17??-estradiol, estriol, and 17??-ethinylestradiol exhibited rapid degradation by soil microorganisms in both aerobic and anaerobic conditions. Rapid degradation rates for estrone, estriol, and 17??-ethinylestradiol occurred in pre-exposed soil under aerobic conditions; half-lives calculated under these conditions were 0.6, 0.7, and 0.8 day, respectively. Unexposed soil showed similar or slightly longer half-lives than pre-exposed soil under aerobic conditions. The exception was 17??-estradiol; in all treatments, degradation in unexposed soil resulted in a shorter half-life (2.1 versus 2.3 days). Anaerobic soils exhibited high biological degradation of estrogens as well. Half-lives of all estrogens ranged from 0.7 to 6.3 days in anaerobic soils. Triclosan degraded faster under aerobic conditions with half-lives of 5.9 and 8.9 days in exposed and unexposed soil. Under anaerobic conditions, triclosan half-lives were 15.3 days in unexposed and 28.8 days in exposed soil. Ibuprofen showed the least propensity toward biological degradation than other chemicals tested. Biological degradation of ibuprofen was only observed in unexposed soil; a half-life of 41.2 days was determined under anaerobic conditions and 121.9 days under aerobic conditions. Interestingly, unexposed soil exhibited a greater ability under anaerobic conditions to biologically degrade tested compounds than previously exposed soil.  相似文献   

16.
A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in different horizons of a chernozem. It was revealed that, under aerobic conditions, all the microorganisms grow irrespective of the soil horizon; fungi and bacteria grow at the first succession stages, and actinomycetes grow at the last stages. It was shown that, in the case of a simulated anaerobiosis commonly used to study anaerobic populations of bacteria, the mycelium of micromycetes grows in the upper part of the chernozem’s A horizon. Under anaerobic conditions, the peak of the mycelium development is shifted from the 3rd to 7th days (typical for aerobic conditions) to the 7th to 15th days of incubation. The level of mycelium length’s stabilization under aerobic and anaerobic conditions also differs: it is higher or lower than the initial one, respectively. Under anaerobic conditions, the growth of fungal mycelium, bacteria, and actinomycetes in the lower part of the A horizon and in the B horizon is extremely weak. There was not any observed growth of actinomycetes in all the chernozem’s horizons under anaerobic conditions.  相似文献   

17.
Specific rates of Hg (203HgCl2) methylation and McHg (14CH3HgI) demethylation in aerobic and anaerobic conditions were determined in samples of surface sediments (0 to 2 cm) taken from five small headwater lakes in Southern Finland. The highest rates of methylation were measured in anaerobic conditions. However, the importance of aerobic methylation increased with increasing Fe and Mn content in sediment. There was little difference between aerobic and anaerobic demethylation. The results demonstrate that the net McHg production in lake sediments depends on the individual characteristics of the lake, particularly pH and and sediment properties. These characteristics seem to affect demethylation in anaerobic conditions and methylation in aerobic conditions.  相似文献   

18.
The resistance of most plants to salt can be impaired by concurrent waterlogging. However, few studies have examined this interaction during germination and early seedling growth and its implications for nutrient uptake. The aim of the study was to examine the response of germination, early growth, and nutrient uptake to salt (NaCl) and hypoxia applied to barley (Hordeum vulgare L. cv. Stirling), in solution culture. Hypoxia, induced by covering seeds with water, lowered the germination from 94% to 28% but salinity and hypoxia together lowered it further to 13% at 120 mM NaCl. While the germination was 75% at 250 mM NaCl in aerated solution, it was completely inhibited at this NaCl concentration under hypoxia. Sodium ion (Na+) concentrations in germinated seedlings increased with increasing salinity under both aerated and hypoxic conditions during germination, while K+ and Mg+ concentrations were decreased with increasing salinity in 6 d old seedlings. After 20 d, control seedlings had the same dry weights of the roots and shoots with and without hypoxia but at 10 mM NaCl and higher, shoot and root dry weight was depressed with hypoxia. Sodium ion increased in roots and shoots with increased NaCl under both aerated and hypoxic conditions while K+ was depressed when salinity and hypoxia were applied together and Ca2+ was mostly decreased by NaCl. In general, hypoxia had greater effects on nutrient concentrations than NaCl by decreasing N, P, S, Mg, Mn, Zn, and Fe in shoots and by increasing B concentrations. The threshold salinity levels decreased markedly for germination, uptake of a range of nutrients, and for seedling growth of barley under hypoxic compared to well‐aerated conditions.  相似文献   

19.
Members of the euryarchaeotal genera Methanolobus and Halobacterium as well as group 1.1c Crenarchaeota were enriched from ectomycorrhizal samples and cultured under anaerobic conditions. 16S rRNA gene sequences of Methanolobus were obtained in a H2 + CO2 atmosphere and autofluorescent putatively methanogenic microbial cells were detected by epifluorescence microscopy of the anaerobic methane-producing enrichment cultures. Halobacterium and group 1.1c Crenarchaeota grew anaerobically when either H2 or CH4 was added to the atmosphere. Group 1.1c Crenarchaeota were also enriched under aerobic conditions on mineral media, but only when methane or methanol was added as carbon sources. The 16S rRNA gene sequences of 1.1c Crenarchaeota grown under both anaerobic and aerobic conditions were highly similar. Our study demonstrates the growth of group 1.1c Crenarchaeota and Halobacteria derived from non-extreme soil environment in non-saline enrichments under anaerobic conditions. The results suggest that 1.1c Crenarchaeota may play a role in the cycling of C-1 substrates in the boreal forest soil ecosystem.  相似文献   

20.
The effect of glyphosate on soil respiration and Hz oxidation in an agricultural soil was investigated. The effects of the pure herbicide and commercial formulation, Roundup® (Monsanto Company), were compared in soil under both aerobic and anaerobic conditions. Both formulations stimulated O2 uptake as well as aerobic and anaerobic CO2 evolution. Roundup caused more stimulation than glyphosate under aerobic incubation conditions; the formulations had an equal effect on anaerobic CO2 evolution. Hydrogen oxidation was inhibited by both formulations in aerobic and anaerobic soil. Aerobic H2 oxidation was inhibited to the same extent by both formulations; Roundup had a stronger inhibitory effect on anaerobic H2 oxidation than did glyphosate.  相似文献   

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