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71.
Marie Smutná Klára Hilscherová Veronika Pašková Blahoslav Maršálek 《Journal of Soils and Sediments》2008,8(3):154-164
Background, aim, and scope
Restoration of lakes and reservoirs with extensive cyanobacterial water bloom often requires evaluation of the sediment quality. Next to the chemical analysis of known pollutants, sediment bioassays should be employed to assess toxicity of the present contaminants and to make predictions of associated risk. Brno reservoir in the Czech Republic is a typical example of water bodies with long-term problems concerning cyanobacterial water blooms. Comprehensive assessment of reservoir sediment quality was conducted since successful reservoir restoration might require sediment removal. An important part of this survey focused on an examination of the utility of Tubifex tubifex and its sublethal biochemical markers for the assessment of direct sediment toxicity.Materials and methods
This complex study included chemical analysis of contaminants (heavy metals, organic pollutants), ecotoxicity testing of sediment elutriates (tests with Daphnia magna, Pseudomonas putida, Sinapis alba, Scenedesmus subspicatus), and other parameters. We have tested in more detail the applicability of T. tubifex as a test organism for direct evaluation of contact sediment toxicity. Survival tests after 14 days of exposure were complemented by an assessment of parameters serving as biomarkers for sublethal effects [such as total glutathione content (GSH), activities of the enzymes glutathione transferase (GST), glutathione peroxidase (GPx), and glutathione reductase (GR)]. The data matrix was subjected to multivariate analysis to interpret relationships between different parameters and possible differences among locations.Results
The multivariate statistical techniques helped to clearly identify the more contaminated upstream sites and separate them from the less contaminated and reference samples. The data document closer relationships of the detected sediment contamination with results of direct sediment exposure in the T. tubifex test regarding mortality but namely regarding the sublethal endpoints rather than the results obtained with other test organisms exposed to sediment elutriates. Aside from the reduction in T. tubifex survival, the sediments with organic pollution caused an increase in glutathione content and increased activities of glutathione S-transferase and glutathione peroxidase in the exposed T. tubifex worms.Discussion
Results of our study confirm the suitability of T. tubifex for toxicity testing of raw waters and sediments. This longer-lasting direct contact test has proven more sensitive and appropriate to reflect a lower level of pollution than do the elutriate tests. Sensitive biochemical changes in T. tubifex, including an elevation in GSH levels and GST activities, reflect a general stimulation of detoxification metabolisms in the presence of xenobiotics. The results also suggest an important role of glutathione and related enzymes in detoxification processes and possible involvement of oxidative stress in toxicity mechanisms in benthic sediment-dwelling worms such as T. tubifex.Conclusions
The complex assessment has identified the more contaminated samples with locally increased concentration of organic pollutants and significant ecotoxicity. The direct sediment contact test with T. tubifex and especially the biochemical parameters corresponded better to the lower level of pollution than the other tests with sediment elutriates. Despite its greater time and cost demands, the direct sediment contact test can provide a more realistic picture of exposure.Recommendations and perspectives
Sediment bioassays should always be included as an integral part of the sediment quality assessment. The direct contact tests also take into account the more hydrophobic pollutants that are not easily available for the water elution but can still be accessible to the organisms. The T. tubifex test is a suitable option for contact sediment toxicity tests also because these animals show measurable sublethal biochemical changes that can be associated with this exposure. 相似文献72.
Michal Némethy Daniel Mihálik Øyvind Steifetten Veronika Rošteková Michaela Mrkvová Marián Janiga 《Scandinavian Journal of Forest Research》2018,33(3):215-221
Many studies have addressed the question of dispersal potential of Ips typographus, however the approach of molecular ecology have been used only in a few of them. Moreover, none of them has done it on fine scale of just one mountain range. Molecular analysis using a set of six polymorphic microsatellite markers was applied in this study. Adult beetles of I. typographus collected in 22 localities of the High Tatra Mountains were used for the study of genetic differentiation between rapidly expanded local populations of bark beetles after windstorm calamities in spruce stands. Almost none genetic differentiation among local populations or among larger spatial units has been revealed. Analyses did not indicate isolation of populations by distance or formation of population structure. This suggests high potential of I. typographus to disperse over large distances and even the possibility to overcome high mountains ridges. 相似文献
73.
Adam Sikora František Kačík Milan Gaff Veronika Vondrová Tatiana Bubeníková Ivan Kubovský 《Journal of Wood Science》2018,64(4):406-416
Thermal modification of wood is an environment-friendly alternative method for improving several properties of wood without the use of chemicals. This paper deals with the examination of color and chemical changes in spruce (Picea abies L.) and oak wood (Quercus robur F.) that occur due to thermal treatment. The thermal modification was performed at 160, 180, and 210 °C according to thermowood process. The color changes were measured by the spectrophotometer and described in the L*a*b* color system. Chemical changes were examined by wet chemistry methods, infrared spectroscopy and liquid chromatography. During the experiment, oak samples showed smaller color changes than spruce samples at all temperature values. During thermal modification, the content of cellulose, lignin, and extractives increases; however, the hemicellulose content drops by 58.85% (oak) and by 37.40% (spruce). In addition to deacetylation, new carbonyl and carboxyl groups are formed as a result of oxidation. Bonds in lignin (mainly β-O-4) and methoxyl groups are cleaved, and lignin is condensed at higher temperatures. 相似文献
74.
Veronika Märkl Stephan Pflugmacher Dietmar A. Stephan 《Water, air, and soil pollution》2017,228(3):111
With an annual production of about 10 Gt concrete is by far the most used solid man-made material. In order to adjust the workability of fresh concrete most often so-called superplasticisers, essentially water-soluble organic polymers, are utilised. As concrete is commonly in direct contact with soil or water, the leaching of organic and inorganic compounds and their environmental impact need to be assessed. The present study contributes to this purpose by investigating leachates from hardened cement pastes gained using the horizontal dynamic surface leaching test. Pastes were prepared with and without superplasticiser. The root growths as well as the germination behaviour of cress (Lepidium sativum) and white mustard (Sinapis alba) were examined with respect to phytotoxicity. Different proportions (100, 50, 25 and 12.5%) of the leachates were considered in the test scheme. The results indicate a positive effect of most of the leachates on seed germination and root growth, although statistical significance was only found in some cases. Both test species showed no or only slight harmful effects as relative root growth exceeded always 66% for S. alba and 74% for L. sativum. Seed germination was not negatively influenced by the leachates. Slight beneficial effects on both test species could be observed for leachates containing superplasticiser compared to samples in absence of superplasticiser. 相似文献
75.
Stenosing tenosynovitis of the abductor pollicis longus muscle causes chronic front limb lameness in dogs. The lesion, similar to de Quervain's tenosynovitis in people, is caused by repetitive movements of the carpus. Thirty dogs with front limb lameness, painful carpal flexion, and a firm soft tissue swelling medial to the carpus were examined prospectively. Seven dogs had bilateral abductor pollicis longus tenosynovitis. Radiographs of the carpus were characterized by a deeper radiolucent medial radial sulcus and bony proliferations medial and slightly cranial to the distal radius, resulting in stenosis of the tendon sheath and subsequent tendinitis. Ultrasonographic examination of the firm soft tissue swelling medial to the carpus was characterized by an irregular hypoechoic abductor pollicis longus tendon or tendinitis in 22 of 37 dogs. Nineteen of 37 abductor pollicis longus tendon sheaths were fluid-filled and all tendon sheaths were thickened, more hyperechoic, with small hyperechoic mineralizations embedded in the connective tissue of the abductor pollicis longus tendon sheath in 25 dogs. Enthesopathy of the abductor pollicis longus tendon was identified in seven dogs. While radiographs of stenosing tenosynovitis of the abductor pollicis longus are helpful in visualizing the deep radial sulcus and osteophytes medial to the distal radius, ultrasonography is useful to distinguish between lesions of the tendon or tendon sheath and to determine thickness and fluid content of the abductor pollicis longus tendon sheath. 相似文献
76.
Hinterhofer C Ferguson JC Apprich V Haider H Stanek C 《New Zealand veterinary journal》2005,53(3):165-170
AIM: To create a computer-based finite element (FE) model of the bovine claw and to use finite element analysis (FEA) to estimate stress and deformation of a physiologically-shaped model claw under static load, to visualise potential material weakness and to evaluate the effect of different flooring conditions. METHODS: Model geometry was derived using digitalised images from a recently trimmed, sound, hind claw from a 4-year-old Austrian Fleckvieh cow. Material properties of bovine claw horn were defined from preliminary investigations and recently established material data, using a modulus of elasticity from 200 to 600 N/mm2. Meshing of the model was performed with 42,127 elements based on 116,141 nodes. Loading of the model was defined at 756 N per claw on a hard and soft surface. RESULTS: The FE model of the bovine claw under a load of 756 N showed only minimal deformation, most of which took place at the axial wall. Highest stresses were evident in the proximal axial wall, the outer edge of the weight-bearing surface and under the heels. The claw-floor contact image showed a pressure distribution resembling the distal rim of the claw wall. On the hard surface, the maximum stresses were three times higher than those on the soft surface. CONCLUSIONS AND CLINICAL RELEVANCE: FEA allowed visualisation of the effects that loading on different floor surfaces have on the biomechanics of the claw. Uneven preparation of the claw sole resulted in high stresses at and close to irregularities of the sole. Consequences were more severe on harder flooring. The model supports the hypothesis that mechanical factors play a substantial role in the pathogenesis of claw lesions. 相似文献
77.
Hertzberg H Larsen M Maurer V 《Berliner und Münchener tier?rztliche Wochenschrift》2002,115(7-8):278-285
For the last 50 years the control of gastro-intestinal nematodes (GIN) in grazing animals has almost entirely been alleviated by the use of anthelmintics. Due to development of resistance against the drugs, especially in the GIN of sheep and goats it has become necessary to develop new, innovative strategies such as the use of nematode destroying fungi. Despite experiments to employ various species against plant and animal parasitic nematodes were already attempted in the 1930's, it was not until the 1990's when selection by simulating passage through the gastro-intestinal tract of cattle led to isolation of the fungus Duddingtonia flagrans that a major breakthrough was achieved. This fungus, producing sticky three-dimensional network and now isolated world-wide, is special due to its capacity to prolifically produce high numbers of thick-walled resting spores, chlamydospores. These spores survive passage through the gastro-intestinal tract of grazing livestock and are capable of growing and subsequently trap nematodes, including larval stages of parasitic nematodes. The great potential of this fungus as a biological control agent has been demonstrated through numerous trials with cattle, sheep, horses, and pigs. But these trials have also pointed towards some potential limitations in the activity spectrum of the fungus (Dictyocaulus, Nematodirus) beside the whole group of parasites spreading through infective stages protected inside resistant eggs (e.g. Ascaris, Trichuris). So far, in the few reported studies conducted, no negative environmental impact has been found, but it is important that further studies are conducted on this important issue. Although the potential use of D. flagrans chlamydospores has been verified through numerous trials it is necessary to develop practical delivery systems such as slow release devices, feed-blocks or similar to be able to implement this tool in future integrated control strategies. Such control strategies could include the use of biological control, grazing management, smart use of existing drugs, parasite resistant animal breeds, bioactive forages, and possibly vaccines. 相似文献
78.
We investigated direct anthelmintic effects associated with the feeding of fresh tanniferous forages against established populations of Haemonchus contortus and Cooperia curticei in lambs. Twenty-four parasite naive lambs were inoculated with a single dose of infective larvae of these two parasites 27 days prior to the start of the feeding experiment. Lambs were individually fed with either chicory (Cichorium intybus), birdsfoot trefoil (Lotus corniculatus), sainfoin (Onobrychis viciifolia) or a ryegrass/lucerne mixture (control) for 17 days. Animals where then united to one flock and subjected to control feeding for another 11 days to test the sustainability of potentially lowered egg excretion generated by tanniferous forage feeding. When compared to the control, administration of all tanniferous forages was associated with significant reductions of total daily faecal egg output specific to H. contortus (chicory: 89%; birdsfoot trefoil: 63%; sainfoin: 63%; all tests P<0.05) and a tendency of reduced H. contortus worm burden (chicory: 15%; birdsfoot trefoil: 49% and sainfoin: 35% reduction). Irrespective of the condensed tannin (CT) containing fodder, no anthelmintic effects were found against C. curticei. Cessation of CT-feeding followed by non-CT control feeding did not result in a re-emergence of faecal egg counts based on faecal dry matter (FECDM) in any group, suggesting that egg output reductions are sustainable. The moderate to high concentrations of CTs in birdsfoot trefoil (15.2 g CTs kg(-1) dry matter (DM)) and sainfoin (26.1 g CTs kg(-1) DM) were compatible with the hypothesis that the antiparasitic effect of these forages is caused by their content of CTs. For chicory (3 g CTs kg(-1) DM), however, other secondary metabolites need to be considered. Overall, birdsfoot trefoil and in particular sainfoin seem promising candidates in contributing to an integrated control strategy against H. contortus not only by mitigating parasite related health disturbances of the host but also by a sustained reduction of pasture contamination. 相似文献
79.
Martin Flajshans Martin Kocour David Gela Veronika Piackova 《Aquaculture International》2004,12(1):103-118
Amphimictic diploid (2n), induced meiotic gynogenic (MeiG) and induced triploid (3n) siblings of tench, Tinca tinca L., were separately nursed, marked and kept in long-term communal testing in pond until sex maturation and natural spawning. Survival rates during the initial periods were lesser in 2n and 3n compared to MeiG population (65%). The first overwintering period showed decreased survival of 3n (62.67%) compared to MeiG (90.0%) and 2n populations (91.67%). Survival rates during the next seasons ranged in 70.50–90.97% similarly in both 3n and 2n while in MeiG population it dropped to 38%. Weight and length growth of all populations studied showed significantly higher growth of 3n females and of 3n in general, compared to 2n and MeiG populations (P < 0.001). Health examinations found metacercaria of Diplosthomus spathaceum in eyes of 2-year-old 3n specimens, weak polyparasitic infections of skin and gills by Dactylogyrus, Trichodina, Thrichophrya, Apiosoma and Chilodonella spp. in 3n and 2n specimens but medium strong to strong infections of 100% of MeiG fish which might contribute to their enhanced mortality. Ploidy analysis of progeny obtained from spontaneous spawning of the broodstock showed 100% diploidy, indicating the following possibilities: 2n population might spawn itself, 2n males might also mate to gynogens, or 3n males might also mate to 2n and/or MeiG females causing spontaneous gynogenesis. Further pedigree analyses will be focused to highlight these questions. 相似文献
80.
Road-deposited sediment, soil and precipitation (RDS) in Bratislava, Slovakia: compositional and spatial assessment of contamination 总被引：2，自引：1，他引：2
Katrina Krčmová Davina Robertson Veronika Cvečková Stanislav Rapant 《Journal of Soils and Sediments》2009,9(4):304-316
Background, aim and scope The urban environment in Bratislava is, in association with rapid urbanisation and industrialisation, significantly influenced
by several potential sources of pollution, including automobile exhaust and industry emmissions. Urban road-deposited sediments
contain many potentially toxic elements such as Pb, Cr, Cu, Zn and also Fe at concentrations much higher than in soil. In
this study, the chemical composition and spatial variability of road-deposited sediments in urban area of Bratislava were
assessed for the elements As, Cd, Cr, Cu, Hg, Ni, Pb, Fe and Mn. Additional evaluation of archive data for soil, snow and
atmospheric dust was undertaken to provide an integrated view on urban environment contamination.
Materials and methods Urban road-deposited sediments (RDS) were collected during summer 2003 and 2004 mainly from major city crossroads. RDS samples
were analysed for total metal content, pseudo-total metal content (HNO3 digestion) and by a sequential extraction method, grain fraction composition and mineralogical composition (X-ray analysis).
Metal concentrations in soil and snow samples from urban and non urban city area were compared.
Results and discussion The highest concentrations for all metals were found in the finest RDS fraction (<0.125 mm). Whilst in the fraction <1 mm
mean concentrations of Cr, Cu and Pb reached 55.2, 143.8 and 34.4 mg kg−1, respectively, for the fraction <0.125 mm, markedly higher contents of these elements were documented at the level of 86.8,
218.4 and 63.1 mg kg−1, respectively. The soil contents of potentially toxic risk elements in the urban area including As, Cr, Cu, Fe, Hg, Mn, Ni,
Pb and Zn were higher than in the non-urban area (except for Cd with similar contents). This distribution pattern of evaluated
chemicals in urban and non-urban area is more evident in the case of winter precipitation (snow). The snow concentrations
of As, Cr, Cu, Fe, Mn, Pb and Zn in the urban area were two tot five times higher than in non-urban area.
Conclusions and recommendations Monitoring of road-deposited sediments, dust, soil and precipitation has confirmed the significant contamination of the urban
environment in Bratislava with potentially toxic elements that can pose a threat for the health of its residents. Future works
should be based on analyses of temporal variability of RDS and analyses of organic matter content. 相似文献