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1.
The effects of Ni on hepatic enzymes of tilapia, viz. acid‐ and alkaline phosphatases, catalase and glucose‐6‐phosphatase, both under in vivo and in vitro conditions reflected the following tendencies. In vivo conditions indicated maximal increase in activity for acid phosphatase at 3.00 ppm, equivalent to 28.5%, followed by a slight decrease and increase thereafter. As for alkaline phosphatase, gradual increase in activity was observed with maximal activity at 9 ppm of Ni, equivalent to 16.8%. Catalase demonstrated similar tendencies with maximal activity at 9.0 ppm, equivalent to 101.2%. In the case of glucose‐6‐phosphatase, the tendency was the reverse with maximal inhibition at 9.00 ppm, i.e. 41.9%. In contrast to in vivo conditions, in vitro systems indicated that all investigated enzymes were inhibited in the region of 4–10% except for catalase which demonstrated a slight increase by 5–6% in activity between concentrations of 10–15 ppm of Ni but thereafter continuous inhibitory effects prevailed.

At cellular level, exposure of tilapia to a lethal dose of 9 ppm of Ni indicated not much of an adverse effect except for a slight depletion in fat and glycogen content. In the case of mitochondria, they were normal and a few large secondary lysosomes were observed. In relation to the cell membrane no dramatic change was detected.  相似文献   

2.
Exposure of Cr to four hepatic enzymes activities of tilapia, viz. acid‐ and alkaline phosphatases, catalase and glucose‐6‐phosphatase, was contrary to the results obtained for Cd and Ni. This is the only heavy metal investigated thus far that dramatically augmented glucose‐6‐phosphatase by approximately 83% at a concentration of 12 mg L‐1 in vivo in lieu of the fact of an initial inhibition of approximately 45 % at a lower concentration of Cr; 6 mg L‐1. In the case of acid phosphatase and catalase activities progressive increment was observed up to 50 and 217% respectively at a concentration of 12 mg L‐1 Cr. On the other hand, in contrast to all the investigated enzymes interestingly alkaline phosphatase was inhibited continuously at all concentrations up to 46% at 12 mgL‐1 Cr. In vitro experiments were contrary to the above mentioned results, whereby all hepatic enzymes were inhibited with major inhibition observed for acid phosphatase of approximately 60% from 5 mgL‐1 Cr onwards in the system.

At cellular level, Cr exposure at a lethal dose of 12 mgL‐1 demonstrated similar effects to that of Cd. In general, the glycogen and fat reserves were depleted while lysosomal activity is increased. As compared to the effects of Cd, the mitochondria did not indicate any prominent reflection in the formation of intramitochondrial bodies. Further, similar to Cd, the cell membrane as well as nucleus were not affected.  相似文献   

3.
The EU vision of sustainable agriculture, land use, forestry and management of natural resources contributes to the balanced exploitation of the environment, taking into account rural development strategy. Whilst the EU directs activities through legislative tools, national systems of public administration are responsible for the implementation of the respective laws. Despite there not being acquis communautaire in public administration, non-formal cooperation has nevertheless emerged and systems of national public administration have to meet EU criteria and ensure the effective implementation of legislation. The paper presents an analysis of how Slovak state administration has converged with EU requirements in the field of sustainable agriculture, land use, forestry and natural resources. Administrative convergence is considered through the internal convergence represented by capacities without legal subjectivity, and through external convergence represented by legal and administrative subjectivity. Both approaches are observed at the central level within specialized public authorities. Local state administration is characterized by the creation of internal administrative capacities with the challenging delimitation of which competences are affected by the process of administrative convergence.  相似文献   

4.
以酱油曲霉(Aspergillus sojae)为吸附剂,对水溶液中微量Cd2+进行了吸附研究.实验考察了预处理方法、菌体用量、pH、温度和吸附时间对吸附的影响,同时分析了其吸附动力学和吸附等温线特性,并对酱油曲霉菌体吸附Cd2+的可能作用机理进行了探讨.结果表明,碱预处理的菌体吸附效果最好.在菌体用量为0.08 g时,对Cd2+的吸附量达到最大,为0.095 mg.g-1.pH值在3.4—8之间,酱油曲霉菌体对Cd2+的吸附效果比较稳定,其最大吸附率出现在pH 3.4.温度在15℃—30℃之间时,菌体对Cd2+的吸附率差异很小,吸附率在88.3%—94.4%之间.二级动力学方程能很好地表征酱油曲霉吸附微量Cd2+的过程,R2在0.99以上,其吸附平衡时间大约2.5 h,线性模型更适于描述该吸附平衡过程.SEM、FTIR分析得出,Cd2+可能是与酱油曲霉菌体表面的羟基、酰胺基、羧基、磷酸基和胺基等基团相络合而被吸附,也可能是形成颗粒沉淀而附着在菌丝上.  相似文献   

5.
Accelerated sea level rise and hurricanes are increasingly influencing human coastal activities. With respect to the projected continuation of accelerated sea level rise and global warming one must count with additional expenses for adaptation strategies along the coasts. On the mountainous island Martinique the majority of settlements are situated along the coast almost at sea level. But potential rises in sea level and its impacts are not addressed in coastal management, even though saltwater intrusion and coastal erosion with increasing offshore loss of sediment are locally already a severe problem. At a sea level rise of 50 cm, one fourth of Martinique’s coastline will be affected by erosion and one fifth of the islands surface will have high probability to get flooded during coastal hazards. This is a growth of 5% of the impact area in comparison to present conditions. This article analyses potential adaptation strategies and argues that the development of a coastal zone management plan considering sea level rise and its impact area is of utmost importance. Empirical assessment models in combination with spatial analysis are useful in obtaining statements about coastal impacts concerning sea level rise. This paper sees itself as recommendation of action not only for Martinique.
Christine SchleupnerEmail:
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6.
Mercury (Hg) exposure is ubiquitous in modern society via vaccines, fish/crustacea, dental amalgam, food, water, and the atmosphere. This article examines Hg exposure in the context of primary exposure to pregnant women and secondary exposure experienced by their unborn babies. Babies in utero are particularly at risk of higher Hg exposure than adults (on a dose/weight basis through maternal Hg transfer via the placenta), and are more susceptible to adverse effects from mercury and its biologically active compounds. It is, therefore, critical that regulatory advisories around maximum safe Hg exposures account for pregnant women and secondary exposure that children in utero experience. This study focused on standardized embryonic and fetal Hg exposures via primary exposure to the pregnant mother of two common Hg sources (dietary fish and parenteral vaccines). Data demonstrated that Hg exposures, particularly during the first trimester of pregnancy, at well-established dose/weight ratios produced severe damage to humans including death. In light of research suggestive of a mercuric risk factor for childhood conditions such as tic disorders, cerebral palsy, and autism, it is essential that Hg advisories account for secondary prenatal human exposures.  相似文献   

7.
Ecosystem-focused models have, for the first time, become available for the combined demersal and pelagic components of a large tropical lake ecosystem, Lake Malawi. These provide the opportunity to explore continuing controversies over the production efficiencies and ecological functioning of large tropical lakes. In Lake Malawi these models can provide important insight to the effect of fishing on fish composition, and the potential competition that the lakefly Chaoborus edulis may have with fisheries production. A mass-balanced trophic model developed for the demersal fish community of the southern and western areas of Lake Malawi was integrated with an existing trophic model developed for the open-water pelagic. Input parameters for the demersal model were obtained from a survey of fish distributions, fish food consumption studies, and from additional published quantitative and qualitative information on the various biotic components of the community. The model was constructed using the Ecopath approach and software. The graphically presented demersal food web spanned four trophic levels and was based primarily on consumption of detritus, zooplankton and sedimented diatoms. Zooplankton was imported into the system at trophic levels three and four through fish predation on carnivorous and herbivorous copepods and Chaoborus larvae. It is proposed that the primary consumption of copepods was by fish migrating into the pelagic zone. Chaoborus larvae in the demersal were probably consumed near the lakebed as they conducted a daily migration from the pelagic to seek refuge in the sediments. This evidence for strong benthic-pelagic coupling provided the opportunity for linking the demersal model to the existing model for the pelagic community so producing the first model for the complete ecosystem. Energy fluxes through the resulting combined model demonstrated that the primary import of biomass to the demersal system was detritus of pelagic origin (72.1%) and pelagic zooplankton (10.6%). Only 15.8% of the biomass consumed within the demersal system was of demersal origin. Lakefly production is efficiently utilised by the lake fish community, and any attempt to improve fishery production through introduction of a non-native plantivorous fish species would have a negative impact on the stability and productivity of the lake ecosystem.  相似文献   

8.
The concept of sustainable development (SD) has highly been debated since it was presented 25 years ago, with ‘hard science’ approaches on one side and more process-oriented approaches on the other side. Academic teaching in SD has emerged in response to this in very different contexts, partly mirroring this academic debate. Some master’s programmes in SD take a strong science approach, while other programmes focus on the process of implementing sustainability projects, sometimes connected with forms of action research and teaching. In this article, we identify diverse views on the concept of SD as well as views on most relevant modes of teaching. We discuss core competencies required for sustainability professionals in their working practices and we organise them in three main clusters: Know, Interact and Be (KIB). The article presents the results of a worldwide survey, which addresses these visions on the concept of SD, the capabilities needed for ‘sustainable development professionals’ and the teaching approach needed. The analysis is based on the responses of 54 lecturers and 287 students active in 34 SD master’s programmes on all continents. The results of this worldwide survey are discussed. We observe in practice some gaps between preferences and practice. Looking at what both lecturers and students see as essential topics to address, some topics get relatively less attention (like the population issue). The identified core competencies (KIB) are supported and all addressed in practice, while the ‘Be’ competencies receive relatively less attention. Suggested consequences for academic teaching include a further matching of programmes with perceived needs and bridging the gap between the experienced teaching approaches in practice with such identified needs.  相似文献   

9.
Data from National Health and Nutrition Examination Survey for children aged 6–11 years for 1999–2014 were used to study time trends and factors affecting the urinary levels of barium, cobalt, cesium, molybdenum, lead, antimony, thallium, and tungsten. Adjusted levels in urine declined every two years by 5.9% for barium, by 1.2% for cesium, by 18.2% for lead, and by 14% for antimony. For every additional smoker smoking inside a home, the levels of barium increased by 10.6% and for lead by 10%, but for tungsten levels decreased by 7.7%.  相似文献   

10.
In order to assist an integrated development of ionic liquids (ILs), a study on the sorption, distribution, and cytotoxicity of a series of 1-alkyl-3-methyl imidazolium tetrafluoroborates with C6 rat glioma cells has been performed. Cellular sorption and distribution among three cellular fractions (cytosol, nuclei, and membranes) were analysed by reversed-phase HPLC (RP-HPLC). Compounds with longer 1-alkyl substituents were sorbed with higher enrichment factors and sorption coefficients per protein than those with shorter 1-alkyl chains. The 1-octyl-3-methyl imidazolium cation (C8MIM) was enriched 17-folds whereas C6MIM and C4MIM were enriched by factors of 3.5 and 2.3, respectively. After fractionation of cells by centrifugation, about 8% of C8MIM was found in the nuclear fractions. The cytotoxicity as estimated by the tetrazolium reductase assay was increasing with the lengths of the 1-alkyl chains from C4MIM to C10MIM. Consistently, cell proliferation rates were decreasing with increasing lengths of the 1-alkyl chains. The results reveal the correlations between lipophilicity, cellular sorption, and cytotoxicity.  相似文献   

11.
In this Comment we refer to our strong reservations concerning the paper by Powell et al. J Coast Conserv, (2012) recently published on the Online First web site of the Journal of Coastal Conservation. The paper makes a number of comments on data obtained from the Permanent Service for Mean Sea Level (PSMSL) and British Oceanographic Data Centre (BODC) which are incorrect or misleading. In addition, some of their comments on sea-level science in general need to be challenged and corrected.  相似文献   

12.
Phototransformation of UC‐54229 (1) [2,3‐dihydro‐2,2‐dimethyl‐7‐benzofuranyl‐N‐(trimethylamino acetyl)‐N‐methyl carbamate chloride] was studied under UV and visible light conditions. Photoirradiation of 1 with UV‐light resulted in the formation of five degradation products which on the basis of their mass and 1H Nmr spectral analysis were characterised as 2, 3, 4, 5 and 6. It was observed that under the influence of light, UC‐54229 was degraded to acetyl‐carbofuran which under similar conditions underwent further transformation to the actual toxicant carbofuran. The degradation products or impurities present in 100% water soluble powder formulation were identified as carbofuran phenol and triethylamine hydrochloride.  相似文献   

13.
Although the peri-urban region around Bogotá, Colombia contains a diversified horticulture sector, local vegetable production suffers from a critical lack of research and availability of un-biased, scientifically validated information on crop management. In this study, we identify current trends and deficiencies in fertilisation and pest management for local vegetable production. We relate pesticide type with target pests, evaluate temporal patterns in pesticide and fertiliser use for a key crop (i.e. spinach) and conduct basic nutrient budget accounting. Personal interviews with vegetable growers were combined with a detailed follow-up of management activities and soil nutrient profiles on pilot farms in two different peri-urban municipalities. Most (84%) vegetable growers relied on personal experience, and indicated a lack of unbiased information on fertiliser effectiveness and pesticide action spectra. The majority of farmers used pesticide mixtures on a calendar basis and commonly applied products below recommended doses. Soil nutrient accounts indicate insufficient fertilisation and a progressive depletion of key nutrients. Extraction rates for the principal vegetable crops exceeded by 33.6%, 20.5% and 93.0% soil nutrient availability of N, P and K, respectively. Organic products are included in local fertilisation schemes, with chicken manure as the principal source, at an average application rate of 6 t ha?1. Our findings could help policymakers and local institutions set a research and extension agenda to promote sustainable peri-urban vegetable production and help secure peri-urban livelihoods while ensuring healthy and safe horticultural production.  相似文献   

14.
Acute static bioassays were conducted for 96 h period with λ-cyhalothrin to determine its acute toxicity to a freshwater catfish, Clarias batrachus. The 96 h LC50 value was estimated to be 5.00 μg l−1 (95% confidence limit: 4.114–5.712). The alterations in behavioral pattern, such as change in the color of skin, hyperactivity, loss of balance, rapid swimming, increased surfacing activity, enhanced rate of opercular activity, as well as prominent rates of convulsions in treated fish were observed with the increasing concentrations of insecticide as compared to the control fish. The results indicate that λ-cyhalothrin is highly effective even at very low concentrations.  相似文献   

15.
The white rot fungi are members of Basidiomycota, which can degrade lignin and form white rot. They are high producers of extracellular laccases. In the present study, pure culture strain of high-temperature and high-laccase production types (numbered as BUA-01) was isolated from the fruiting bodies of a white rot fungus collected in the campus of Beijing University of Agriculture. The taxonomic characteristic was determined based on morphological and ITS sequence analysis. Furthermore, the optimal culture conditions for the mycelia were determined, including carbon source, nitrogen source, C/N ratio, growth factors, temperature, and pH. Extracellular laccase production was investigated in liquid fermentation with different concentrations of Cu (CuSO4) as inducer. Decolorizing activity of the fermentation broth was assayed using three azo dyes: Evans blue, methyl orange, and eriochrome black T. The results showed that the strain possessed the highest homology toward Trametes hirsuta, with the homology ratio of 100% and the genetic distance of 0, suggesting that the strain BUA-01 belonged to the genus Trametes. The culture condition investigated revealed that the optimal condition for mycelia growth included the following: carbon source, starch; nitrogen source, soybean powder and yeast extract; C/N ratio, 40/1 and 10/1; temperature, 37 °C; and pH, 6.0-7.0. The assayed growth factors had no significant effect on mycelial growth. It demonstrated high laccase activity in liquid fermentation. The highest extracellular laccase activity of 1 081.33 ± 6.3 U/mL was observed in the broth with a Cu adjunction concentration of 0.25 mmol/L after a 96-h culture period. It was about 26-fold higher than that of the control group. The isolated strain exhibited significant decolorizing activity toward the azo dyes Evans blue, methyl orange, and eriochrome black T, with the decolorization rate at 12 h of 93.31% ± 0.16%, 92.37% ± 0.42%, 79.25% ± 0.64%, respectively. This suggests that the strain possesses potential applications in laccase production and dye degradation. © 2018 Science Press. All rights reserved.  相似文献   

16.
In order to study how water level fluctuations (WLF) of reservoir influence the macroinvertebrate in tributary bay, we studied the effect of WLF of the Three Gorges Reservior on macroinvertebrate communities in Xiangxi Bay, and the time lags of such effect, based on the surveys in spring and summer from 2005 to 2010. In this research, WLF was represented by water level drawdown (WLD) and the sum of absolute values of rate of water level fluctuations (RWlf). Pearson correlation analysis was used to analyze the relationship between WLF and macroinvertebrates. No significant correlation was found between macroinvertebrates and sum of absolute values of RWLF, while WLD showed significant influence on some biotic parameters. In spring, WLD did not cause significant effect to macroinvertebrates (P > 0.05). In summer, however, the influence was significant, especially in the area of the downstream (XX01 - XX02) of the Xiangxi Bay (P < 0.05). The middle reach of the bay (XX05), located in the conjunction area between Xiangxi Bay and a secondary tributary of the TGR, was also affected significantly (P < 0.05). The relative abundance of Tubificidae declined with the increase of the WLF, while abundance of Chironomidae increased. The time lags of the influence to macroinvertebrates were about 15 days. This analysis indicated that WLF in the mainstream of the reservoir mainly influences the downstream of the tributary bay, and also affects the conjunction area of the secondary tributary. Chironomidae are more tolerant than Tubificidae in water-body with dramatic disturbance, therefore can be considered as the indicator of the effect of summer WLF on macroinvertebrates.  相似文献   

17.
Tide gauge data have become increasing accessible to non-specialists through the availability of records over the Internet. Our original paper, “Use of local tidal records to identify relative sea level change: accuracy and error for decision makers”, focused on highlighting the potential pitfalls in tide gauge data manipulation that non-specialists may not be aware of. Since publication, Rickards et al. have made helpful observations and raised queries about certain elements within our paper, which we respond to here.  相似文献   

18.
The high consumption of crabs (Ucides cordatus) stimulated interest in the present study on the northern coast of Brazil, which encompasses a preserved area of mangrove forest. The objective was to describe and quantify the transfer of metals from the muddy sediments to the leaves of the Rhizophora mangle, and thence the crabs and humans. The samples were collected along two transects, while samples of hair were obtained from local habitants. The pH, interstitial salinity, Eh (mV) were measured, the granulometry and mineralogical and multi-element chemical analyses were run, and the organic material determined. The sediments are silty-clayey, composed of quartz, kaolinite, iron oxides, and illite, as well as smaller portions of smectite, pyrite, halite, and high levels of SiO2 (56.5 %), Al2O3 (18.5 %), and Fe2O3 (7 %). The elements Zn, Sr, As, and Zr are concentrated in the leaves, while the bioaccumulation of Zn, Se, Sr, and As was recorded in the crabs, of which, Se is the most concentrated in the tissue of the muscles and the hepatopancreas. The concentrations of nutrient and toxic elements were similar in all age groups (hair samples), with only Hg presenting an increasing concentration between infants and adults. The highest rates of transfer were recorded for the elements Zn and Se in the crabs and Hg in leaves and hair. The accumulation of metals in the leaves and crabs reflects the chemical composition of the sediments and low rates of sediment-vegetation-crab transfer, with the exception of Hg, which accumulated in the hair.  相似文献   

19.
This long‐term inhalation study was designed to describe the toxicity and the carcinogenic risk from Cd compounds because it had been shown from former long‐term inhalation studies that cadmium choloride induced primary lung tumors in Wistar rats. It was therefore logical to examine whether other cadmium compounds to which human beings are more frequently exposed have also carcinogenic potency. In a long‐term inhalation study cadmium aerosols consisting of cadmium chloride (CdCl2), cadmium oxide (CdO) as dusts and fumes, cadmium sulfate (CdSO4), cadmium sulfide (CdS) and a combination of cadmium oxide/zinc oxide were used. Wistar rats were continuously exposed in inhalation chambers for 18 months 22 hrs a day or for 40 hrs a week. The studies will be terminated at the mean survival life time of the species. The aerosols were generated by several different systems. The particles of the cadmium aerosols have the average mass medium diameters in the range from 0.2 to 0.5 μm.  相似文献   

20.
In the present study, fruiting bodies of a wild medicinal mushroom, 'Huaier, ' were collected from Populus canadensis in the Beijing Xiangshan Park. The pure culture strain was obtained from fruiting bodies using the tissue isolation method. It was stored and numbered as XS-01. It was systematically classified using morphological and ITS identification. Further studies were focused on mycelia optimum culture conditions and laccase production by liquid fermentation. A 598-bp partial ITS region sequence (GenBank accession number KY93348) was obtained using PCR method. Phylogenetic tree and genetic distance analysis were performed using the MEGA 6.0 software. The present strain possessed the highest homology (100%) with Perenniporia robiniophila, and the genetic distances were 0.000. Based on the ITS sequencing and morphological characteristics of fruiting bodies and mycelia, XS-01 was identified as P. robiniophila. Based on mycelial growth rate and quality, mycelia optimum culture conditions were revealed to be as follows: the optimum carbon sources were starch and maltose, the optimum nitrogen source was yeast extracts, the optimum C/N ratio range was 30/1 - 60/1, the best growth temperature was 32 °C, the optimum pH was 7, and the optimum growth factor was VB1. Further study of Cu2+ on extracellular laccase production revealed that 1.0 mmol/L Cu2+ could significantly enhance the enzyme production, with the highest activity of 417.5 U/mL when cultured for 96 h and an increase ratio of 93.4% to the control. On the other hand, 2.0 mmol/L Cu2+ can markedly decrease the enzyme production laccase activity at 96 h to 79.0 U/mL, which was 36.6% of that of the control. In conclusion, a pure strain of T. robiniophila with high extracellular laccase activity was obtained, suggesting its potential application for artificial cultivation and laccase production. © 2018 Science Press. All rights reserved.  相似文献   

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