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Molecular techniques to evaluate ecosystem health
MOLECULAR TECHNIQUES TO EVALUATE ECOSYSTEM HEALTH D. Sawa School of Animal and Microbial Sciences, The University of Reading, Reading, United Kingdom
GENETIC CHANGES ASSOCIATED WITH INSECTICIDE EXPOSURE IN MOSQUITOES A. Callaghan Division of Zoology, School of Animal & Microbial Sciences, Universily of Reading, Whiteknights PO Box 228, Reading RG6 6AJ, UK
The health status of an ecosystem may be evaluated by monitoring the effects of environmental pollutants on representative organisms; this monitoring may be carried out in a number of ways and at different levels. Exposure of organisms to genotoxic chemicals results in the formation of covalently bound adducts between the chemical (or one of its metabolites) and the DNA; these adducts may cause mutations and cytogenetic changes. The primary effects of such exposure (i.e. adduct formation) and subsequent effects on the DNA (cytogenetic damage, mutation) may be monitored using a number of assays of varying sensitivity and specificity. Recent developments in molecular biology offer new possibilities for detecting DNA damage. We examined whether DNA fingerprinting by arbitrarily primed polymerase chain reaction (AP-PCR) can show differences in the DNA fingerprints of shore crabs (Carcinus maenas) exposed to benzo(a)pyrene in the laboratory and of crabs from control and from polluted areas. The results indicate that differences between control and exposed shore crabs were detectable and that DNA fingerprinting by AP-PCR offers a usetil alternative biomarker assay for the detection of the genotoxic effects of environmental pollutants.
Organophosphate insecticides (OPs) are applied to control Culex pipiens mosquitoes which, in many parts of the world, are important vectors of disease. The insects have fought back through the selection of genetic variants of the target enzyme acetylcholinesterase and the metabolic enzymes carboxylesterases, glutathione-s-transferases and cytochrome P45Os which can detoxify the OPs. Gene amplification, increased transcription and point mutations have all been selected to combat the xenobiotics. These mutations can be detected using biochemical or molecular biomarkers to determine whether a control programme is likely to fail. The same tests can also be used as biomarkers of pollution. However, the presence of these mutations cannot always be used as markers of genetic selection since Cwlex mosquitoes with mutations migrate world-wide. Generally these mutations are present in unselected populations at extremely low frequency. Selection with insecticides merely increases the frequency. However environmental stress does affect the genetic recombination system and insecticides may therefore directly affect the production of new mutations. This could have important implications not only for insect control but for any application of these chemicals.
Pathophysiology of birch populations affected by aerial emission. A.F.Babich, E.I.Golubeva, V.K.Zhirov Department of‘Biogeography, Moscow State Lomonosov University, Russia The goal of our investigation was to study plant responses to permanent impact of aerial pollution at cells level and community level. The investigations were carried our in the impact zone of &everonikel>> smelter complex (Monchegorsk. Kola Peninsula). As a test-object were used communities of hybrid forms of Betula pendula Roth. x Betula pubescence Ehrh., being 30-40 years old. The birch leaves were collected from 8 plots within the distance of I- 30 km. from the smelter. The tendency was revealed of green pigments content to decrease in 3 times with the rising of pollution, in this, the rate of the B-carotin synthesis increased. Concentrations of the copper in leaves tissues 150-250 mg/lOOOg of the dry weight activate the growth. According to our study, mechanism of leaves growth is not interrelated with assimilating tissues formation, but is a result of cells spreading and increase of water content in tissues. By the detailed analyze of pigment content and morphological characteristics of birch leaves it was revealed that the studied hybrid forms are differed by the ( and toleration to pollution impact. Phytocenotic analyze showed, that modifications at cells level lead to the transformation of the plant community structure. However, under moderate pollution impact communities <>to adapt by the alteration at the higher level of their organization.
EFFECTS OF XENOBIOTICS ON THE ENERGY METABOLISM IN AQUATIC INVERTBRATES STUDIED WITH DIRECT MICROCALORIMETRY O.-P. Penttinen, and J.V.K. Kukkonen Department ofBiology, Unwers@ ofJoensuu, F&and Direct calorimetry provides an advanced method to study whole-animal metabolic events in small aquatic organisms exposed to environmental stress. To determine toxicantinduced changes in the metabolic heat dissipation (= metabolic rate), freshwater invertebrates Chironomus rzparzus (Insecta) and Lumbricultts varlegatus (Oligochaeta) were exposed to four benzene derivatives. Results show that relationship between metabolic rate and toxic stress can assume all possible directions: increase, decrease or be unaffected by exposure to toxicants. .4bove the compoundspecific subthreshold level, an increase in heat dissipation was produced by 2,4_dinitrophenoi, pentachlorophenol and 2,4,5trichlorophenol and this was closely correlated with the dose. A decrease in the heat dissipation was caused by 1,2,4-trichlorobenzene(1,2,4-TCB) and dose-response relationship was less consistent. The most notable observation was that each compound may have significantly different internal toxicities. This probably reflects the interaction of compounds’ lipophiliclties and acidities and their combined influence on bioaccumulation and effects on energy transducing membrane by uncoupling oxidative phosphorylation.
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GENETIC CHANGES ASSOCIATED WITH INSECTICIDE EXPOSURE IN MOSQUITOES A. Callaghan Division of Zoology, School of Animal & Microbial Sciences, Universily of Reading, Whiteknights PO Box 228, Reading RG6 6AJ, UK
The health status of an ecosystem may be evaluated by monitoring the effects of environmental pollutants on representative organisms; this monitoring may be carried out in a number of ways and at different levels. Exposure of organisms to genotoxic chemicals results in the formation of covalently bound adducts between the chemical (or one of its metabolites) and the DNA; these adducts may cause mutations and cytogenetic changes. The primary effects of such exposure (i.e. adduct formation) and subsequent effects on the DNA (cytogenetic damage, mutation) may be monitored using a number of assays of varying sensitivity and specificity. Recent developments in molecular biology offer new possibilities for detecting DNA damage. We examined whether DNA fingerprinting by arbitrarily primed polymerase chain reaction (AP-PCR) can show differences in the DNA fingerprints of shore crabs (Carcinus maenas) exposed to benzo(a)pyrene in the laboratory and of crabs from control and from polluted areas. The results indicate that differences between control and exposed shore crabs were detectable and that DNA fingerprinting by AP-PCR offers a usetil alternative biomarker assay for the detection of the genotoxic effects of environmental pollutants.
Organophosphate insecticides (OPs) are applied to control Culex pipiens mosquitoes which, in many parts of the world, are important vectors of disease. The insects have fought back through the selection of genetic variants of the target enzyme acetylcholinesterase and the metabolic enzymes carboxylesterases, glutathione-s-transferases and cytochrome P45Os which can detoxify the OPs. Gene amplification, increased transcription and point mutations have all been selected to combat the xenobiotics. These mutations can be detected using biochemical or molecular biomarkers to determine whether a control programme is likely to fail. The same tests can also be used as biomarkers of pollution. However, the presence of these mutations cannot always be used as markers of genetic selection since Cwlex mosquitoes with mutations migrate world-wide. Generally these mutations are present in unselected populations at extremely low frequency. Selection with insecticides merely increases the frequency. However environmental stress does affect the genetic recombination system and insecticides may therefore directly affect the production of new mutations. This could have important implications not only for insect control but for any application of these chemicals.
Pathophysiology of birch populations affected by aerial emission. A.F.Babich, E.I.Golubeva, V.K.Zhirov Department of‘Biogeography, Moscow State Lomonosov University, Russia The goal of our investigation was to study plant responses to permanent impact of aerial pollution at cells level and community level. The investigations were carried our in the impact zone of &everonikel>> smelter complex (Monchegorsk. Kola Peninsula). As a test-object were used communities of hybrid forms of Betula pendula Roth. x Betula pubescence Ehrh., being 30-40 years old. The birch leaves were collected from 8 plots within the distance of I- 30 km. from the smelter. The tendency was revealed of green pigments content to decrease in 3 times with the rising of pollution, in this, the rate of the B-carotin synthesis increased. Concentrations of the copper in leaves tissues 150-250 mg/lOOOg of the dry weight activate the growth. According to our study, mechanism of leaves growth is not interrelated with assimilating tissues formation, but is a result of cells spreading and increase of water content in tissues. By the detailed analyze of pigment content and morphological characteristics of birch leaves it was revealed that the studied hybrid forms are differed by the (
EFFECTS OF XENOBIOTICS ON THE ENERGY METABOLISM IN AQUATIC INVERTBRATES STUDIED WITH DIRECT MICROCALORIMETRY O.-P. Penttinen, and J.V.K. Kukkonen Department ofBiology, Unwers@ ofJoensuu, F&and Direct calorimetry provides an advanced method to study whole-animal metabolic events in small aquatic organisms exposed to environmental stress. To determine toxicantinduced changes in the metabolic heat dissipation (= metabolic rate), freshwater invertebrates Chironomus rzparzus (Insecta) and Lumbricultts varlegatus (Oligochaeta) were exposed to four benzene derivatives. Results show that relationship between metabolic rate and toxic stress can assume all possible directions: increase, decrease or be unaffected by exposure to toxicants. .4bove the compoundspecific subthreshold level, an increase in heat dissipation was produced by 2,4_dinitrophenoi, pentachlorophenol and 2,4,5trichlorophenol and this was closely correlated with the dose. A decrease in the heat dissipation was caused by 1,2,4-trichlorobenzene(1,2,4-TCB) and dose-response relationship was less consistent. The most notable observation was that each compound may have significantly different internal toxicities. This probably reflects the interaction of compounds’ lipophiliclties and acidities and their combined influence on bioaccumulation and effects on energy transducing membrane by uncoupling oxidative phosphorylation.
104