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541.
N‐acetyltransferase (NAT) activity was determined in 100 fish (Oreochromis mossambicus) livers using 2‐aminofluorene and p‐aminobenzoic acid as substrates. Overall, the liver NAT activity of the 50 females was higher than the liver NAT activity of the 50 males. The activities (mean ± SD) of NAT from kidney, blood, intestine, and liver of males was 0.42 ± 0.11, 0.12 ± 0.03, 0.12 ± 0.08, and 1.56 ± 0.54 nmol/min/mg protein for the acetylation of 2‐aminofluorene and 0.36 ± 0.09, 0.09 ± 0.01, 0.11 ± 0.04, and 0.46 ± 0.15 nmol/min/mg protein for the acetylation of p‐aminobenzoic acid. In kidney, blood, intestine, and liver from female fish, the activities obtained were 1.60 ± 0.12, 0.35 ± 0.07, 0.15 ± 0.09, and 1.89 ± 0.50 nmol/min/mg protein for 2‐aminofluorene and 0.95 ± 0.11, 0.27 ± 0.03, 0.13 ± 0.09, and 0.57 ± 0.12nmol/min/mg protein for p‐aminobenzoic acid. Kinetic constants for arylamine N‐acetyltransferase activity in kidney, blood, intestine, and liver from fish with rapid, intermediate, and slow acetylator activity were determined. Apparent K m and V max values for 2‐aminofluorene were 5.5 and 7‐fold higher for liver than for the other tissues. Apparent K m and V max values for p‐aminobenzoic acid were 3.5 and 4.7‐fold higher for liver than for the other tissues. Based on the 2‐aminofluorene NAT activity of liver, there appears to be a polymorphism in NAT activity with 16 rapid, 28 intermediate, and 56 slow acetylators among the 100 fish assayed. This is the first demonstration of acetyl CoA: arylamine N‐acetyltransferase activity in fresh water fish and could lead to the development of a fish model for monitoring the effect of pollution of water environments on native species. 相似文献
542.
Burger JR Chesh AS Muñoz P Fredes F Ebensperger LA Hayes LD 《Behavioral ecology and sociobiology》2012,66(1):57-66
Social animals are susceptible to high infection levels by contact-transmitted parasites due to increased conspecific interaction.
Exotic parasites are known to have adverse consequences on native hosts. We examined the relationship between social group
size and exotic ectoparasite loads, and adult infection levels with per capita fitness and offspring survival in the plural
breeding rodent Octodon degus in central Chile. Degus at our site were almost entirely infected by two exotic ectoparasites: the fleas Leptopsylla segnis and Xenopsylla cheopis. Neither group size nor number of females per group predicted the abundance of either exotic flea species. The per capita
number of pups (per capita fitness) that emerged from burrow systems used by known social groups was negatively correlated
with abundance of L. segnis but not X. cheopis. On adults, X. cheopis abundance was three times greater than L. segnis but was not significantly correlated with per capita fitness. In females, L. segnis abundance was negatively correlated with peak body mass during pregnancy. Adult ectoparasite load was not correlated with
offspring survival. Based on these results, we hypothesize that high infection levels of L. segnis result in decreased reproductive fitness of adult female degus but are not a cost of sociality because parasite loads are
not predicted by social group size. Further work is needed to experimentally test this hypothesis and to determine if L. segnis serves as a vector for a deleterious pathogen. Lastly, the lack of native ectoparasites may explain why a previous study
at our site determined that behavioral adaptations needed to cope with high ectoparasite burdens (e.g., grooming) are not
extensive in degus; they simply have not had the coevolutionary time needed for selection of these behaviors. 相似文献
543.
印染废水生化出水中有机污染物特性及在硫酸镁混凝过程中的去除行为 总被引:3,自引:1,他引:2
以某印染废水二级生化出水为研究对象,考察了生化出水中有机污染物中各组分含量、分子量分布特点等特性,以及各类有机物在硫酸镁混凝处理过程中的去除行为.实验结果表明,该印染废水的生化出水溶解性有机物的主要成分是疏水性物质,以溶解性有机碳(DOC)表征时占总DOC的78%,其中非酸疏水物质约占46%,而以UV254表征时约占总55%,以美国染料生产协会色度值(ADMI7.6)表征时为97%,其中以非酸疏水物质的贡献最大,达到66%,并且非酸疏水物质中不饱和双键或芳香环有机物的含量较高.生化出水中的DOC主要集中在小于1000 D的有机物上,占37%.在硫酸镁的最佳混凝条件下,可以有效地去除由大分子量的非酸疏水物质引起的色度,而对小分子量的有机物也有一定的去除效果. 相似文献
544.
545.
546.
M. Hein S. Rotter M. Schmitt-Jansen P. C. von der Ohe W. Brack E. de Deckere C. Schmitt D. de Zwart L. Posthuma E. M. Foekema I. Muñoz S. Sabater H. Segner E. Semenzin A. Marcomini J. van Gils B. van Hattum L. A. van Vliet 《Environmental Sciences Europe》2010,22(3):217-228
The EU Water Framework Directive (WFD) requires the achievement of good ecological and chemical status in European river basins. However, evidence is increasing that a majority of European water bodies will not achieve this goal. Nutrient emissions and related eutrophication together with hydromorphological alterations have been suggested as the major driving forces of this insufficient ecological status. MODELKEY (511237 GOCE, FP6) provides strong evidence that toxic chemicals also affect the ecological status of European rivers. This was demonstrated in the case study rivers Elbe, Scheldt and Llobregat on different scales. This paper summarises key findings of MODELKEY including recommendations for WFD implementation. We ? provide evidence of toxic stress in aquatic ecosystems, ? provide evidence that impairment of ecological status results from impact of multiple stressors, ? suggest a tiered approach to assess impact of chemicals on ecological status, ? suggest a new approach for deriving candidate compounds for monitoring and prioritisation, ? call for consideration of bioavailability and bioaccumulation in chemical status assessments, ? suggest improvements for WFD water quality monitoring programmes, ? provide new integrated tools for basin-scale risk assessment and decision making, ? developed a Decision Support System to support river basin management. These key results will be presented in a series of ten integrated sections; for the scientific details please refer to publications listed on the MODELKEY website (http://www.modelkey.org/). This article also looks beyond MODELKEY and proposes a combination of MODELKEY diagnostic tools with recent ecological methods to further improve effectiveness of river basin management. 相似文献
547.
Joan Solé Albert Sans Magí Riba Gloria Rosell Esmeralda Rosa Lourdes Muñoz Maria Pilar Bosch Angel Guerrero 《Chemoecology》2008,18(2):99-108
Summary. The differing antagonist activity of (Z)-13-hexadecen-2-one (Z11 – 14 :MK, 1) and its 1,1,1-trifluoro derivative (Z11 –14 :TFMK, 2), two closely related analogues of the European corn borer pheromone Ostrinia nubilalis (Z strain), and their rationale is reported. Both chemicals exhibited some electrophysiological activity, and topical application
of 10 pg of pheromone analogue on male antennae was sufficient to induce significantly lower depolarization responses to the
pheromone versus untreated insects. In a wind tunnel, the number of European corn borer males attracted to sources containing
mixtures of 1 + pheromone in ratios ≥ 1 :1 was significantly lower than the number attracted to a source containing pheromone alone. Source
contact behaviour was dramatically impaired when the 1 + pheromone blend reached a ratio of 10 :1, in which only 2% of males displayed source contact in the presence of antagonist.
When compound 1 was present at the source, males usually flew upwind with occasional downwind reversals; when compound 2 was present at the lure, males performed wider crosswind reversals, with little progress toward the source. In the field,
traps baited with mixtures of both compounds with the pheromone in ratios of 5 :1 and 10 :1 elicited a significantly decreased
number of male catches. In esterase inhibition assays, compound 2 was a potent inhibitor (IC50 = 70 nM), whereas the non-fluorinated compound 1 was not. The different activity of both compounds is presumed to be due to different mechanisms of action; considerations
for using methyl ketone analogues as new behavioural antagonists of the pheromone are outlined. 相似文献
548.
市售绿茶自混合水溶液中吸附除去铬(Ⅵ)的研究 总被引:9,自引:0,他引:9
本文探讨了国产茶叶(市售云南产绿茶)的结构、成份和溶解,以及在不同浓度、时间、pH、温度的条件下,自混合溶液中大量吸附铬(Ⅵ)的特性。结果表明,浸泡过的茶叶对Cr(Ⅵ)的吸附率略低于未泡茶样,在一定条件下,Cr(Ⅵ)的吸附量可达到4.96mg/g。我们建议在这复杂体系中,用离子交换吸附过程形成表面配合物,以及发生化学作用的综合吸附机理来解释。 相似文献
549.
江汉下游农村经济区在湖北省中部,经济区位居中处优,在湖北省农村经济活动中具有举足轻重的地位,该区乡镇企业较发达,特别是天门、仙桃、潜江三市尤为突出。当前我国正处于向社会市场经济转轨初期,全省处于如何实现国民经济和社会发展“九五”计划和2010年远景目标建议重要开端时期,为了阐明本区在“转轨”和“实现建议”时期的作用,就今后的发展方向等问题作了初步探讨,并进一步提出相应对策措施。 相似文献
550.
De la Torre AI Jiménez JA Carballo M Fernandez C Roset J Muñoz MJ 《Chemosphere》2000,41(10):1629-1635
Swine sewage could be source of nutrients and pollutants. This work estimates the environmental risk in nine samples from different farm treatment systems based on the evaluation of their effects in Daphnia magna acute test, and on the assessment of Cu, Zn and ammonia as main contributors. NH3 and Cu were responsible for LC50 results (1-5% of dilution). Organic compounds were quantified through several extraction methods (SPMDs, SPE and solvent extraction). A more exhaustive extraction was performed in an additional sample, which showed indole and phenol recoveries much higher than the previous ones. This method also includes PCBs (430 ppb) and fatty acids (approximately =150 ppm) quantification. 相似文献