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    Assessment of the sediment toxicity in Bulgarian and Turkish rivers using the biomarkers in chironomus riparius Mg. (Diptera: Chironomidae)
    (2012) Duran, Mustafa; Michailova, Paraskeva; Sarı, Adile; Ilkova, Julia; Şen, Alaatin; Karadurmuş, Erdal
    As a model organism we used Chironomus riparius Mg. - a widely distributed species that can be reared in the laboratory conditions and has excellent salivary gland chromosomes. The study showed that the genome at cytogenetical and biochemical levels is a sensitive biomarker and can serve as early - warning indicators of environmental impact of chemicals. Analysis of trace metals in sediment of Chaya River (Asenovgrad, Bulgaria, 2010) and Derincay River (Turkey, 2010), indicated higher concentrations of trace metals (Pb, Cr, Cu, Cd) in comparison with reference data. The response at cytogenetical level is determined by changes of gene expression of key structures (BRs and NOR) and increased in structural chromosome somatic aberrations. Changes of gene expression are indicated by decreasing the transcriptional activity of BRs and NOR: very often they occurred in the intermediate state of activity or BRs are in collapse. The cells with somatic rearrangements of C. riparius from polluted Derincay and Chaya River were in 16.94% and 36.36% respectively, which were significantly higher than those of the control (Derincay River: G = 125.53, P<0.001; Chaya River: G = 73.81, P<0.001). Somatic index was the highest in the sample from Chaya River - 3.25, following by Derincay River -1.58, while it was 0.13 in the control sample. The response of the C. riparus at biochemical level is characterized by increaseing amount of metallothionein (MT) higher in Chaya River in comparison of Derincay River. Similarly, the other studied enzyme activities, GST and EROD, showed on the average 20% and 24% higher activities respectively, in Derincay than in Chaya. In addition, in accordance with above enzyme activities, the level of AChE inhibition is about 10% higher in Derincay River than in Chaya River. As a result, alterations in these biochemical parameters could be regarded as valid reflections of the increased trace metals in Derincay and Chaya Rivers. It could be concluded that the environmental diagnose quality by multilevel approach (cytogenetical and biochemical) will enable better understanding of the impact of pollutants on organisms and should be successful implemented in environmental monitoring procedures.
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    Genome response of model invertebrates and vertebrates species to stress agents in the environment
    (2010) Michailova, Paraskeva; Atanasov, Nasko; Ilkova, Julia; Chassovnikarova, Tsenka G.; Duran, Mustafa; Karadurmuş, Erdal
    The genome response of model invertebrate and vertebrate species to stress agent in the environment was studied. The both group of species were collected from contaminated water stations along Marisa (Kemera) and Chaya (Asenovgrad) Rivers and terrestrial areas near Asenovgrad. The structural and functional alterations of the salivary gland chromosomes of Chironomus riparius as well as the aberrations of mitotic chromosomes of Apodemus flavicollis and Microtus arvalis were analyzed. In the polytene chromosomes of C. riparius a high spectrum of somatic aberrations were detected, which appeared in significantly higher frequency in comparison of the control (Kemera: G=37.99, df=1, P<0.001; Asenovgrad, G = 42.82, df = 1, P<0.001). Also, the key structure of the polytene chromosomes: Balbiani rings and Nucleolar Organizer decreased their normal function activity which indicates that they are direct target for the stress of contaminants in the environment. The frequency of aberrant cells of small rodents (Apodemus flavicollis and Microtus arvalis) was significantly higher than the control, well expressed in M. arvalis (G = 4.54, df =1, P <0.05). In both groups of studied species genome instability were found, realized by many structure chromosome rearrangements which can be used as a cost-effective indicator of genotoxicity, and hence suitable markers of potential environmental stress. However, the studied species show differences in their response which might be depended on their biology. © 2010 Taylor and Francis Group, LLC.
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    Öğe
    Structural and functional alterations in salivary gland chromosomes and enzyme activity of Chironomus riparius Mg. (Diptera, Chironomidae) from anthropogenically polluted sites in Bulgaria and Turkey
    (Taylor & Francis Ltd, 2012) Michailova, Paraskeva; Ilkova, Julia; Duran, Mustafa; Karadurmus, Erdal; Berber, Ridvan; Sen, Alaatin
    The effect of environment contaminants on genome instability and changes in enzyme activity (acetylcholinesterase (AChE), glutathione S-transferase activities (GST), etoxyresorufin O-deethylase (EROD) and metallothionein (MT)) of Chironomus riparius Mg. from Bulgarian and Turkish stations over two years (2009, 2010) as well as laboratory reared larvae were studied. Physicochemical analysis of the sediments from the field stations indicated the presence of heavy metal pollutants (Cr, Cu, Mn, Pb, and Cd) whose concentrations were higher than the reference data. Genome instability was determined by somatic structural and functional alterations of the polytene chromosomes. In the field sites of both countries somatic aberrations occurred at a significantly higher frequency (p < 0.001) compared with control and laboratory material. C. riparius in sediments with higher concentrations of trace metals (Derincay River, Turkey and Chaya River, Bulgaria), was found to possess a high spectrum of somatic chromosome rearrangements with a somatic index of 2.53 and 3.25 respectively. Changes in functional activity included decreased activity of the Balbiani rings (BRs) and nucleolar organizer (NOR). The observed chromosome alterations agree with the high degree of trace metal pollution and high activity of the studied enzymes. However, no correlation between single somatic chromosome rearrangements and concentrations of specific metal ions was defined. The data are discussed in the light of the wide variety of interactions of metals in nature. The results show that the genome response and biochemical markers are sensitive markers of toxicity and provide early warning indicators of contaminants in the environment.