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The use of the biomarkers chlorophylls and carotenoids, for the interpretation of the effects in lemna minor after exposure of two herbicides with different mode of action
Get PDFThe impact of herbicides in aquatic vascular plants is often investigated in toxicity laboratory studies. Lemna minor is a fast growing aquatic vascular plant regularly used as a bioindicator in ecotoxicological dose-response studies. Chlorophylls and carotenoids are among the most commonly used biomarkers when monitoring the effects of toxicants. For this study we chose two herbicides, tritosulfuron and metribuzin, with different modes of action. Tritosulfuron is a sulfonylurea herbicide, an amino acid synthesis inhibitor. Metribuzin, on the other hand, is a triazinone herbicide, a photosystem II inhibitor.
In the study we investigated changes in content of photosynthetic pigments, in particular chlorophylls a, b and carotenoids, caused by tritosulfuron and metribuzin in Lemna minor. We also evaluated these changes compared to growth rate (based on frond number) endpoint on this species. The toxicity of the two herbicides was assessed by growth inhibition tests in Lemna minor based on standard OECD protocols (7 day test). Growth inhibition, caused by the two herbicides, was measured daily from day 0 until day 7. The four effect concentrations chosen (EC100, EC75, EC50, EC25), were evaluated from pre-tests. The amounts of chlorophyll a and b as well as carotenoids were measured pectrophotometrically on days 1, 3 and 5 after exposure.
Obtained results showed that adverse effects on Lemna minor, based on growth inhibition caused by the herbicides, were not clearly connected with a decrease in chlorophyll a, b and carotenoids content. After exposure to various concentrations of tritosulfuron, Lemna minor chlorophyll and carotenoid content showed a decrease which was more intense as the time of exposure increased. For metribuzin, although there was a decrease in pigment content in high concentration treatments on day 3, on day 5 there was no evident effect in pigment concentrations in any treatment. On the other hand, growth rate was reduced with the increase of the concentration of both herbicides on days 3 and 5; growth rate differed statistically between all concentration treatments, except the lowest concentration. We can conclude that for both herbicides growth rate is a more sensitive endpoint to measure the toxicity than pigments. Moreover, tritosulfuron (the amino acid biosynthesis inhibitor) affects pigment concentration more promptly and more intensely than metribuzin (the photosystem II inhibitor) in concentrations causing similar growth inhibition. Further research on the ways that chlorophylls and carotenoid are affected by these two herbicide categories is necessary
Instrumental Analysis of bacterial cells growth under incubation with Crocus sativus L. extracts using FT-IR spectroscopy
Get PDFFoodborne illness is a threat to public health and challenge for food industry. Very young children, pregnant women, people with compromised immune systems and the elderly are at the most risk. Foodborne illness also known as food poisoning usually arises from improper handling, preparation, or food storage and is associated with microbial pathogens. Bacteria are a common cause of foodborne illness and especially Salmonella and Escherichia coli. At present food industry uses chemical additives in several processes in order to prevent bacterial growth and extend the shelf life of foods. However, these substances have adverse effects. In the current study, Crocus sativus L. extracts were tested as potential natural antimicrobial agents. The antimicrobial activity of plants extracts was studied towards Gram-negative strains belonging to the above species. Fourier transform infrared spectroscopy (FT-IR) was applied in order to evaluate the changes in the cellular composition of target bacterial cells after their exposure to extracts
The use of the biomarkers chlorophylls and carotenoids, for the interpretation of the effects in lemna minor after exposure of two herbicides with different mode of action [POSTER]
No full textThe impact of herbicides in aquatic vascular plants is often investigated in toxicity laboratory studies. Lemna minor is a fast growing aquatic vascular plant regularly used as a bioindicator in ecotoxicological dose-response studies. Chlorophylls and carotenoids are among the most commonly used biomarkers when monitoring the effects of toxicants. For this study we chose two herbicides, tritosulfuron and metribuzin, with different modes of action. Tritosulfuron is a sulfonylurea herbicide, an amino acid synthesis inhibitor. Metribuzin, on the other hand, is a triazinone herbicide, a photosystem II inhibitor.
In the study we investigated changes in content of photosynthetic pigments, in particular chlorophylls a, b and carotenoids, caused by tritosulfuron and metribuzin in Lemna minor. We also evaluated these changes compared to growth rate (based on frond number) endpoint on this species. The toxicity of the two herbicides was assessed by growth inhibition tests in Lemna minor based on standard OECD protocols (7 day test). Growth inhibition, caused by the two herbicides, was measured daily from day 0 until day 7. The four effect concentrations chosen (EC100, EC75, EC50, EC25), were evaluated from pre-tests. The amounts of chlorophyll a and b as well as carotenoids were measured pectrophotometrically on days 1, 3 and 5 after exposure.
Obtained results showed that adverse effects on Lemna minor, based on growth inhibition caused by the herbicides, were not clearly connected with a decrease in chlorophyll a, b and carotenoids content. After exposure to various concentrations of tritosulfuron, Lemna minor chlorophyll and carotenoid content showed a decrease which was more intense as the time of exposure increased. For metribuzin, although there was a decrease in pigment content in high concentration treatments on day 3, on day 5 there was no evident effect in pigment concentrations in any treatment. On the other hand, growth rate was reduced with the increase of the concentration of both herbicides on days 3 and 5; growth rate differed statistically between all concentration treatments, except the lowest concentration. We can conclude that for both herbicides growth rate is a more sensitive endpoint to measure the toxicity than pigments. Moreover, tritosulfuron (the amino acid biosynthesis inhibitor) affects pigment concentration more promptly and more intensely than metribuzin (the photosystem II inhibitor) in concentrations causing similar growth inhibition. Further research on the ways that chlorophylls and carotenoid are affected by these two herbicide categories is necessary
Who killed the Cretan dwarfs? : The relation between late Quaternary environmental changes and the extinction of the Cretan megafauna
No full textMorphology of articular surfaces can solve a phylogenetic issue: one instead of two ancestors for Candiacervus (Mammalia: Cervoidea)
Get PDFUnsupervised level set parameterization using multi-scale filtering
Get PDFThis paper presents a novel framework for unsupervised level set parameterization using multi-scale filtering. A standard multi-scale, directional filtering algorithm is used in order to capture the orientation coherence in edge regions. The latter is encoded in entropy-based image `heatmaps', which are able to weight forces guiding level set evolution. Experiments are conducted on two large benchmark databases as well as on real proteomics images. The experimental results demonstrate that the proposed framework is capable of accelerating contour convergence, whereas it obtains a segmentation quality comparable to the one obtained with empirically optimized parameterization
Metal bioaccumulation in tissues of M. galloprovincialis in conjuction with seawater metal levels
Get PDFAdolescents' subjective health complaints in their social contexts
Get PDFThe aim of the study was to investigate the extent to which Greek adolescents' perceived wellbeing in their family, school and peer context predicted Subjective Health Complaints (SHC)
