13 documents found, page 1 of 2
Contaminant driven genetic erosion: a case study with Daphnia longispina
Ribeiro, Rui; Baird, Donald J.; Soares, Amadeu M. V. M.; Lopes, IsabelNatural populations exposed to pollutants are predicted to experience a loss of genetic diversity, especially through genetic drift, gene flow (emigration), and/or selection (as sensitive genotypes may be lost). In the present study, the authors discuss the use of selectable markers and neutral markers to evaluate a contaminant-driven loss of genetic diversity and possible implications of genetic erosion on pop...
Population growth rate responses of Ceriodaphnia dubia to ternary mixtures of s...
Barata, Carlos; Fernández-San Juan, María; Feo, Maria Luisa; Eljarrrat, Ethel; Soares, Amadeu M. V. M.; Barceló, Damià; Baird, Donald J.When considering joint toxic apical effects at higher levels of biological organization, such as the growth of populations, the so-called pharmacological mode of action that relies on toxicological mechanistic effects on molecular target sites may not be relevant. Such effects on population growth rate will depend on the extent to which juvenile and adult survival rates and production rates (juvenile developmen...
Exposição a agentes perturbadores naturais e antropogénicos: consequências na d...
Lopes, Isabel; Martins, Nelson; Baird, Donald J.; Ribeiro, RuiA perda de diversidade genética devido a contaminação antropogénica pode aumentar o risco de extinção das populações expostas aquando sujeitas a ulteriores agentes de perturbação. O presente estudo pretendeu investigar o efeito de dois agentes perturbadores na diversidade genética de uma população laboratorial do cladócero planctónico dulçaquícola Daphnia longispina: predação (dois níveis de intensidade) e...
Fear and loathing in the benthos: Responses of aquatic insect larvae to the pes...
Pestana, João L. T.; Loureiro, Susana; Baird, Donald J.; Soares, Amadeu M. V. M.The influence of interactions between pesticide exposure and perceived predation risk on the lethal and sub-lethal responses of two aquatic insects was investigated using the pesticide imidacloprid, and a combination of predator-release kairomones from trout and alarm substances from conspecifics. Laboratory experiments examined feeding and respiration rates of the caddisfly Sericostoma vittatum as well as the ...
Exposição a agentes perturbadores naturais e antropogénicos: consequências na d...
Lopes, Isabel; Martins, Nelson; Baird, Donald J.; Ribeiro, RuiA perda de diversidade genética devido a contaminação antropogénica pode aumentar o risco de extinção das populações expostas aquando sujeitas a ulteriores agentes de perturbação. O presente estudo pretendeu investigar o efeito de dois agentes perturbadores na diversidade genética de uma população laboratorial do cladócero planctónico dulçaquícola Daphnia longispina: predação (dois níveis de intensidade) e cont...
Life-history responses of Daphnia magna Straus to binary mixtures of toxic subs...
Barata, Carlos; Baird, Donald J.; Nogueira, António J. A.; Agra, Ana Raquel; Soares, Amadeu M. V. M.Two prevailing theoretical models: concentration addition (CA) and independent action (IA), predict mixture toxicity on the basis of known toxicities of the mixture components. To date, both models have been in most occasions evaluated using unicellular in vivo responses or biochemical in vitro responses. However, when considering more complex models such as the whole organism physiology or life-history traits,...
Genetic adaptation to metal stress by natural populations of Daphnia longispina
Lopes, Isabel; Baird, Donald J.; Ribeiro, RuiLoss of genetic diversity in natural populations as a result of chemical contamination has been reported in some studies. Here, four field populations of Daphnia longispina, two from sites historically impacted by acid mine drainage (AMD) and two from reference sites, were used to address four objectives: (1) identify differences in sensitivity between the stressed and reference populations; (2) distinguish bet...
Toxicity of binary mixtures of metals and pyrethroid insecticides to Daphnia ma...
Barata, Carlos; Baird, Donald J.; Nogueira, A. J. A.; Soares, A. M. V. M.; Riva, M. C.Two different concepts, termed concentration addition (CA) and independent action (IA), describe general relationships between the effects of single substances and their corresponding mixtures allowing calculation of an expected mixture toxicity on the basis of known toxicities of the mixture components. Both concepts are limited to cases in which all substances in a mixture influence the same experimental endp...
Resistance to metal contamination by historically-stressed populations of Cerio...
Lopes, Isabel; Baird, Donald J.; Ribeiro, RuiField populations of daphnids historically-stressed by metal contamination may show increased resistance to those contaminants. This study was undertaken aiming to confirm/infirm three main hypotheses: (1) field populations living in historically-impacted environments are more tolerant to metal stress than populations from reference sites; (2) resistance differences are genetically-determined, i.e., differences...
Interclonal variation in the performance of Daphnia-magna Straus in chronic bio...
Soares, Amadeu M. V. M.; Baird, Donald J.; Calow, PeterAs an ecotoxicological test organism, Daphnia magna Straus has a long history and is now used extensively. Despite this, considerable variation in interlaboratory bioassays using the same reference toxicant has been reported. Using a standard quantitative genetics approach, the relative tolerance of different genotypes of Daphnia magna to two toxicants (sodium bromide and 3,4-dichloroaniline) was assessed. As e...