Effects of acetaminophen in <Emphasis Type="Italic">Brassica juncea</Emphasis> L. Czern.: investigation of uptake,translocation, detoxification,and the induced defense pathways

Purpose  

Besides classical organic pollutants and pesticides, pharmaceuticals and their residues have nowadays become recognized as relevant environmental contaminants. The risks of these chemicals for aquatic ecosystems are well known, but information about the pharmaca-plant interactions and metabolic pathways is scarce. Therefore, we investigate the process of uptake of acetaminophen (N-Acetyl-4-aminophenol) by Brassica juncea, drug-induced defense responses and detoxification mechanisms in different plant parts.     

Modeling the surface–atmosphere exchange of ammonia

New parameterizations for surface–atmosphere exchange of ammonia are presented for application in atmospheric transport models and compared with parameterizations of the literature. The new parameterizations are based on a combination of the results of three years of ammonia flux measurements over a grassland canopy (dominated by Lolium perenne and Poa trivialis) near Wageningen, the Netherlands and existing parameterizations from literature. First, a model for the surface–atmosphere exchange of ammonia that includes the concentration at the external leaf surface is derived and validated. Second, a parameterization for the stomatal compensation point (expressed as Γ_s, the ratio of [NH₄⁺]/[H⁺] in the leaf apoplast) that accounts for the observed seasonal variation is derived from the measurements. The new, temperature-dependent Γ_s describes the observed seasonal behavior very well. It is noted, however, that senescence of plants and field management practices will also influence the seasonal variation of Γ_s on a shorter timescale. Finally, a relation that links Γ_s to the atmospheric pollution level of the location through the ‘long-term’ NH₃ concentration in the air is proposed.     

Characterisation of PM10 emissions from woodstove combustion of common woods grown in Portugal

A series of source tests was performed to evaluate the chemical composition of particle emissions from the woodstove combustion of four prevalent Portuguese species of woods: Pinus pinaster (maritime pine), Eucalyptus globulus (eucalyptus), Quercus suber (cork oak) and Acacia longifolia (golden wattle). Analyses included water-soluble ions, metals, radionuclides, organic and elemental carbon (OC and EC), humic-like substances (HULIS), cellulose and approximately l80 organic compounds. Particle (PM₁₀) emission factors from eucalyptus and oak were higher than those from pine and acacia. The carbonaceous matter represented 44–63% of the particulate mass emitted during the combustion process, regardless of species burned. The major organic components of smoke particles, for all the wood species studied, with the exception of the golden wattle (0.07–1.9% w/w), were anhydrosugars (0.2–17% w/w). Conflicting with what was expected, only small amounts of cellulose were found in wood smoke. As for HULIS, average particle mass concentrations ranged from 1.5% to 3.0%. The golden wattle wood smoke presented much higher concentrations of ions and metal species than the emissions from the other wood types. The results of the analysis of radionuclides revealed that the ²²⁶Ra was the naturally occurring radionuclide more enriched in PM₁₀. The chromatographically resolved organics included n-alkanes, n-alkenes, PAH, oxygenated PAH, n-alkanals, ketones, n-alkanols, terpenoids, triterpenoids, phenolic compounds, phytosterols, alcohols, n-alkanoic acids, n-di-acids, unsaturated acids and alkyl ester acids.     

Person–organization and person–supervisor fits: Employee commitments in a Chinese context

The present study simultaneously examined people's perceptions of person–organization (PO) and person–supervisor (PS) fit and related these perceptions to employees' commitments. Three‐hundred‐and‐sixty employee–supervisor dyads from Taiwanese organizations reported about their PO fit and PS fit perceptions. In addition, supervisors reported about their perceptions of fit and guanxi with each of their employees. Results indicated that PO and PS fit perceptions both had an independent and additive relationship with organizational commitment. The link between employee PS fit perceptions and organizational commitment was mediated by commitment to the supervisor. Both employee and supervisor fit perceptions contributed to commitment to the supervisor through their influence on the quality of the leader‐member exchange (LMX). Guanxi could not explain additional variance in LMX and supervisor commitment. Implications for theory and practices regarding person–environment fit, commitment, and LMX are discussed. The study findings offered suggestions for a new Theory of Multiple Fits. Copyright © 2010 John Wiley & Sons, Ltd.     

Closing the phosphorus loop in England: The spatio-temporal balance of phosphorus capture from manure versus crop demand for fertiliser

Every year 90 million tonnes of housed livestock manures are produced in the UK. This is a valuable reservoir of global phosphorus (P) and a point in the cycle where it is vulnerable to being lost from the terrestrial system. Improved manure management for the effective reuse of phosphorus is vital to simultaneously tackle a major source of water pollution and reduce our dependence on imported fertilisers. This paper quantifies, for the first time, the spatial and temporal challenges of recycling the required amount of manure P from areas of livestock production to areas of crop production in eight regions of England. The analysis shows that England has a P deficit and therefore the capacity to fully utilise the manure P on arable land, but that uneven spatial distribution of livestock poses a significant challenge to closing the P loop in agriculture. Two of the eight regions were shown to have surplus manure P, with the remaining six regions having P deficits, indicating that an annual export of 4.7 thousand tonnes P (2.8 million tonnes manure) must take place from the west to the east of the country each year to balance P supply and demand. Moreover, housed manure production peaks between October and February, requiring an excess of 23.0 thousand tonnes P (15 million tonnes manure) to be stored until it can be used for crop fertilisation from March onwards. The results demonstrate the scale of the challenge in managing manure P in an agricultural system that has separated livestock production from crop production, a pattern that is echoed throughout the developed world. To overcome the spatial and temporal challenges, a logistical system is recommended that will balance the nutrient potential (nitrogen and P content and availability) and pollution potential (eutrophication, greenhouse gas emissions, particulates and nitrous oxide from transport) for cost-effective and environmentally compatible redistribution of manure P from areas of surplus to areas of deficit, when required.     

Marine Protected Area Management in South Africa: New Policies,Old Paradigms

A historical perspective on MPA identification and governance in South Africa reflects the continued influence of a top-down and natural science-based paradigm, that has hardly changed over the past half century, despite the wealth of literature, and a growing consensus, that advocates the need to adopt a more integrated and human-centered approach. Based on extensive research in two coastal fishing communities, the paper highlights impacts and conflicts arising from this conventional approach to MPA identification, planning and management. It argues that failure to understand the particular fishery system in all its complexity, in particular the human dimensions, and involve resource users in planning and decision-making processes, undermines efforts to achieve conservation and fisheries management objectives. The customary rights of local resource users, and their food and livelihood needs in relation to marine resources, need to be acknowledged, prioritized and integrated into planning and decision-making processes. Convincing ecologists, fisheries scientists and managers, that MPA success depends on addressing the root causes of resource decline and incorporating social factors into MPA identification, planning and management, remains a huge challenge in South Africa.     

Carbon conversion and metabolic rate in two marine sponges

The carbon metabolism of two marine sponges, Haliclona oculata and Dysidea avara, has been studied using a ¹³C isotope pulse-chase approach. The sponges were fed ¹³C-labeled diatoms (Skeletonema costatum) for 8 h and they took up between 75 and 85%. At different times, sponges were sampled for total ¹³C enrichment, and fatty acid (FA) composition and ¹³C enrichment. Algal biomarkers present in the sponges were highly labeled after feeding but their labeling levels decreased until none was left 10 days after enrichment. The sponge-specific FAs incorporated ¹³C label already during the first day and the amount of ¹³C label inside these FAs kept increasing until 3 weeks after labeling. The algal-derived carbon captured by the sponges during the 8-h feeding period was thus partly respired and partly metabolized during the weeks following. Apparently, sponges are able to capture enough food during short periods to sustain longer-term metabolism. The change of carbon metabolic rate of fatty acid synthesis due to mechanical damage of sponge tissue was studied by feeding sponges with ¹³C isotope–labeled diatom (Pheaodactylum tricornutum) either after or before damaging and tracing back the ¹³C content in the damaged and healthy tissue. The filtration and respiration in both sponges responded quickly to damage. The rate of respiration in H. oculata reduced immediately after damage, but returned to its initial level after 6 h. The ¹³C data revealed that H. oculata has a higher metabolic rate in the tips where growth occurs compared to the rest of the tissue and that the metabolic rate is increased after damage of the tissue. For D. avara, no differences were found between damaged and non-damaged tissue. However, the filtration rate decreased directly after damage.     

Hovering guards of the stingless bee <Emphasis Type="Italic">Tetragonisca angustula</Emphasis> increase colony defensive perimeter as shown by intra- and inter-specific comparisons

Social insects need to defend their nest against robbery, parasitism and predation. The stingless bee Tetragonisca angustula is unique in that it has guards that hover near the nest entrance in addition to guards that stand at the entrance. We tested both the general hypothesis that hovering guards increase the effectiveness with which flying intruders are detected and the specific hypothesis that hovering guards improve the detection of workers of the obligate robber bee, Lestrimellita limao. In an intraspecific study comparing colonies, we found a strong positive relationship between the number of hovering guards and the distance at which a dummy robber bee or L. limao worker, experimentally moved towards the nest entrance, was detected. These results were mirrored in an interspecific study showing that four species of stingless bees with similar population colonies but which lacked hovering guards, detected L. limao only at the nest entrance, in contrast to T. angustula. In addition, we found that a greater number of attacks by guards occurred when dummies were impregnated with citral, a major component of L. limao mandibular gland odour. Our results support the hypothesis that T. angustula hovering guards increase the detection perimeter for flying intruders, especially L. limao.     

Influence of coagulation mechanisms and floc formation on filterability

Minimizing particles in water is a key goal for improving drinking water quality and safety.The media filtration process,as the last step of the solid–liquid separation process,is largely influenced by the characteristics of flocs,which are formed and controlled within the coagulation process.In a laboratory-based study,the impacts of the physical characteristics of flocs formed using aluminum sulfate on the filtration treatment of two comparative water samples were investigated using a photometric dispersion analyzer and a filterability apparatus.In general,the optimum dosage for maximizing filterability was higher than that for minimizing turbidity under neutral p H conditions.For a monomeric aluminum-based coagulant,the charge neutralization mechanism produced better floc characteristics,including floc growth speed and size,than the sweep flocculation mechanism.In addition,the charge neutralization mechanism showed better performance compared to sweep flocculation in terms of DOC removal and floc filterability improvement for both waters,and showed superiority in turbidity removal only when the raw water had high turbidity.For the different mechanisms,the ways that floc characteristics impacted on floc filterability also differed.The low variation in floc size distribution obtained under the charge neutralization mechanism resulted in the flocs being amenable to removal by filtration processes.For the sweep flocculation mechanism,increasing the floc size improved the settling ability of flocs,resulting in higher filter efficiency.     

北京地区菜田土壤抗生素抗性基因的分布特征

为研究北京地区菜田土壤抗生素抗性基因(antibiotic resistance genes,ARGs)的污染状况和分布特征,采集了11个长期施用粪肥蔬菜基地的温室土壤和大田土壤,进行了抗生素以及ARGs种类和丰度的检测.结果表明,菜田土壤中四环素类抗生素残留量最高,其次为磺胺类抗生素,温室土壤抗生素残留普遍高于大田土壤.温室和大田土壤磺胺类抗性基因sul1、sul2和四环素类抗性基因tet L的检出率均为100%.温室土壤的Ⅰ类整合子(int I1)检出率比大田土壤高1.5倍.定量PCR的检测结果表明,菜田土壤中sul2和tet L的相对丰度介于10-4~10-2之间,温室土壤sul2和tet L的相对丰度普遍高于大田土壤.sul2的相对丰度与磺胺二甲嘧啶和强力霉素的含量显著正相关(P0.05),tet L相对丰度与抗生素含量无明显相关性(P0.05).本研究结果对于掌握北京地区农田土壤ARGs的污染现状,以及从ARGs角度评估农艺措施具有重要的指导意义.