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51.
Stefan Trapp 《Environmental Sciences Europe》2000,12(5):246-255
Phytoremediation is the quite novel technique of cleaning polluted sites through the use of plants. Phytoremediation methods are comparatively cheap, are accepted by the public and are ecologically advantageous, compared to common technological approaches. Until today, there have been only a few examples for successful applications. One reason is that the processes occurring are complex, and a full clean up may require many years. Plants have an influence on the water balance of a site, they change redox potential and pH, and stimulate microbial activity of the soil. These indirect influences may accelerate degradation in the root zone or reduce the leaching of compounds into the groundwater. Compounds taken up into plants may be metabolised, accumulate, or volatilise into air. Based on these processes, several phytoremediation methods have been developed: Phytoextraction, rhizofiltration, phytostabilisation, rhizound phytodegradation, pump and tree, land farming, phytovolatilisation, hydraulic control and even more. Already in use are plants (and here mainly willows, poplars and grasses) for the degradation of petroleum products, aromatic hydrocarbons (BTEX), chlorinated solvents, explosives and cyanides. Phytotoxicity and pollutants mass balance have rarely been documented carefully. Often, the success of the projects was not controlled, and only estimates can be made about the applicability and the potential of phytoremediation. This lack of experience about possibilities and limitations seems to be a hindrance for a broader use of these techniques. 相似文献
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53.
Borut Poljšak Zoltán Gazdag Miklós Pesti Metka Filipič Stefan Fujs Nelli Farkas 《毒物与环境化学》2013,95(1):141-157
Given the wide industrial use of chromium (Cr) and its environmental contamination, chromium represents a risk to humans exposed to the metal. Considering that Cr(VI) is a potent oxidizing agent that increases intracellular oxidation and DNA damage, it would be worth considering the pretreatment of cells with antioxidants as a means of preventing Cr(VI)-induced toxicity. The objective of this study was to pretreat yeast cells with the water-soluble vitamin E analogue Trolox in an effort to increase cell tolerance against reactive chromium and reactive oxygen species formed during Cr(VI) reduction. Results revealed a decrease in Cr(VI)-induced cytotoxicity and mitotic gene conversions in Trolox-pretreated cells. The protective effect of Trolox in Cr(VI) induced genotoxicity was confirmed also with the prokaryotic Salmonella typhimurium SOS/umu test. Pretreatment of cells with Trolox (1) increased total Cr bioaccumulation, (2) decreased Cr(VI)-induced intracellular oxidation, (3) decreased Cr(V) persistence and (4) increased OH? formation in yeast extracts. These findings might be useful in directing future investigations concerning the use of Trolox as a human antioxidant supplement, and in clinical applications related to Cr-induced genotoxicity in occupational and environmental situations where chromium is a problem. 相似文献
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55.
Stefan Berking 《Die Naturwissenschaften》1997,84(9):381-388
Hydra is famous for its ability to regenerate missing structures. Even aggregates of single cells transform eventually into normally
shaped animals. This indicates a communication within the tissue and within the aggregates which determines the spatial pattern
of gene expression. Such pattern-forming systems are thought to play a decisive role in the control of self-organization during
embryogenesis. Marine and fresh water hydrozoa appear to allow an access to such a system. Although the molecular components
are still mostly unknown, the regulatory properties of the pattern-forming system are increasingly well understood, and this
may help eventually to identify the components involved. 相似文献
56.
Algae blooms, which can be caused by eutrophication, drastically influence the ecology and behaviour of aquatic organisms. Such impact is often demonstrated in the context of mate choice and predator–prey interactions. In contrast, the influence of increased turbidity on social behaviour is less well understood, although it may have strong influence, at both the level of the individual and the population. We aimed to address this gap in our knowledge by using the well-described preference of three-spined sticklebacks (Gasterosteus aculeatus) to shoal with the larger of two shoals as model behaviour. In our experiments focal fish had the choice between two shoals of different sizes, either in clear or in turbid water containing green algae. Fish in clear water spent significantly more time near the larger shoal, while fish in algae water showed no significant preferences. Furthermore, fish tested in clear water changed more often between the shoals than fish tested in algae water. These results indicate that eutrophication-induced algae blooms have the potential to alter social decisions of sticklebacks. Such changes of social decisions do not only influence the behaviour of individuals, furthermore it might influence entire populations. This might eventually lead to changes of the structure of the social system. 相似文献
57.
Stefan Garthe Katrin Ludynia Ommo Hüppop Ulrike Kubetzki Juan F. Meraz Robert W. Furness 《Marine Biology》2012,159(9):1907-1915
We investigated migration and wintering of adult northern gannets (Morus bassanus) breeding in east Scotland, North Sea, by deploying geolocation loggers over three winters. The wintering ranges of these birds varied from the North Sea to the Atlantic off West Africa. Flight time was taken as a proxy for migration and foraging effort. Gannets wintering off Africa had higher total flight times during migration than birds wintering further north. Total flight times in different wintering regions were generally low. Birds off West Africa consistently spent < 25 % of daylight hours in flight, but birds further north showed more variable values that may reflect more variable weather or food availability. Winter sea surface temperatures ranged from 9 °C (North Sea) to 16 °C (West Africa). Thermostatic costs in winter as estimated by measuring thermal conductance in carcasses in still air and water were 28 % higher in North Sea than off West Africa. This effect is aggravated by higher thermostatic costs caused by stronger wind chills in the North Sea compared to the conditions off West Africa. Birds wintering close to the UK arrived at the colony on average 12 days earlier than birds wintering off West Africa. We conclude that the net cost-benefit analysis may be similar for all wintering areas investigated. 相似文献
58.
The correlation of data on the elements obtained by instrumental chemical analysis of highly representative plant samples led to the establishment of a first Biological System of Elements (BSE) in 1994. Including other physiological parameters like availability of chemical elements, transport, storage, etc. it is clear, that aside from the bioinorganic aspects of coordination chemistries of given elements, features of essentiality or toxicity depend on their interference with enzymatic processes. Notably, the latter are not to be considered as purely catalytic transformations, but are instead related to the reproduction of organisms in a direct or indirect manner — as autocatalytic: a process whereby a protein containing some metal or burdened in function by its presence is indirectly involved in its own reproduction. Stoichiometric Network Analysis (SNA) explicitly deals with the general dynamics of such autocatalytic systems. Given there is a relationship between the kinds of metal or metalloid species and the key biological/biochemical transformations to be promoted using them — a relationship which is the topic of bioinorgnaic chemistry-, and that biochemistry is in effect about systems which can reproduce and thus behave autocatalytically, one can expect SNA to yield statements on the basic features of biology and biochemistry as well. 相似文献
59.
In mammals, the chemical profiles of individuals are complex and variable mixtures, and animals perceive information based on variation in the overall quality of these mixtures. A variety of compounds potentially involved in chemical communication have been characterized in the urine of different felid species, but little is known about the information content of felid scent marks. In this study, we investigated whether chemical composition of Eurasian lynx Lynx lynx urine was related to sex, reproductive state, and individual identity. We further analysed if elemental sulphur in lynx urine could serve as a dietary cue or as an indicator for the freshness of a scent mark. We collected urine from captive and wild Eurasian lynx, and analysed volatile constituents of urine by means of solid phase microextraction and gas chromatography-mass spectrometry. Our results show that lynx scent profiles contain sex-specific information on reproductive state, as well as individual identity cues. Urine marks are, therefore, well-suited to fulfil a role in reproductive behaviour and social organisation of wild lynx populations. Relative sulphur content was unrelated to time since last feeding, but decreased with age of the urine sample. The influence of diet and body condition on scent profiles should be further investigated by means of experimental studies, and may shed more light on the messages encoded in carnivore scent-marks. 相似文献
60.