16.7. gill ion transporters and cell volume regulation: effects of copper in estuarine invertebrates

The aim of this study was to evaluate the possible involvementof different mechanisms of ion transport on copper accumula-tion in isolated gill cells from the blue crab Callinectes sapidusacclimated to salinity 30 ppt. A combination of a fluorescencetechnique (Phen Green) with different pharmacological tools(amiloride, phenamil, furosemide, EIPA, SITS, bafilomycin A1,ouabain, and acetazolamide) was used. The following mechan-isms involved in gill Na+ and Cl− homeostasis were evaluated:Na+ channel, Na+,K+,2Cl− co-transporter, and Na+/H+ and Cl−/HCO3

− exchangers. Three key enzymes involved in cellularosmoregulation were also analyzed: V-ATPase, Na+,K+-ATPase, and carbonic anhydrase. Data obtained clearlyindicated that gill copper accumulation in the blue crab C.sapidus depends, directly or indirectly, of the activity of someion transporters and enzymes involved in Na+ cellularhomeostasis.

doi:10.1016/j.cbpa.2007.06.172

16.7. Gill ion transporters and cell volume regulation: Effectsof copper in estuarine invertebrates

Souza, M.M. and Bianchini, A.Fundação Universidade Federal do Rio Grande, RS, Brazil

mmsouza@uel.br

In the present study, we analyzed the copper effect on cell volumeregulation in gill isolated cells from two estuarine invertebrates:the clam Mesodesma mactroides (osmoconformer) and the bluecrabCallinectes sapidus (osmoregulator). Cell volume regulationwas evaluated by image analysis. Data obtained showed thatcopper exposure induced shrinkage of clam gill cells and swellingof crab gill ones, both in a concentration-dependent manner.These differential responses could be associated with differentmechanisms of ion transport involved in the cell volumemaintenance in osmoconformers and osmoregulators. Data oncell volume regulation were then obtained in either the absence orthe presence of copper after exposure to different ion transportblockers, such as amiloride, EIPA, and furosemide, as well asenzyme inhibitors, such as ouabain. In fact, results obtained showthat different mechanisms of ion transporters are involved in thecell volume maintenance in the two estuarine species studied.They also suggest that copper is targeting differentmechanisms ofion transport in those species.

doi:10.1016/j.cbpa.2007.06.173

16.8. Physiological and biochemical parameters of curimbasexposed to gasoline water-soluble fraction during 96 h

Simonato, J.D., Pereira, C.A., and Fernandes, M.N.,and Martinez, C.B.R.

Universidade Estadual de Londrina, PR, Brazil

cbueno@uel.br

The present work was designed to investigate the effects ofgasoline water-soluble fraction (GWSF) on some functionalparameters of the Neotropical freshwater fish Prochiloduslineatus. Juveniles of P. lineatus were exposed to GWSF oronly to clean water (control group) in static toxicity tests and theywere sampled after 96 h to collect blood samples and liver. Bloodsamples were used for hemoglobin, hematocrit and number of redblood cell (RBCs) determinations; plasma samples were used forosmolarity measurements and the determination of osmolalityand glucose, Na+, Cl− concentrations. Fish livers supernatantswere used for glutathione-S-transferase (GST) and catalasemeasurements. The fish exposed to GWSF showed significantincrease in liver GST activity, liver catalase activity and bloodglucose, in relation to control group. Hematocrit and hemoglobincontent were significantly lower than in control group very likelydue to hemolysis. No significant differences were observedbetween control and GWSF-exposed fish in the other analyzedparameters. The enhanced GSTactivity indicates the activation ofbiotransformation pathways for the compounds present inGWSF. The increased liver catalase activity indicates theactivation of anti oxidant defense. The observed hyperglycemiais generally described as part of the fish stress response, in termsof carbohydrate metabolism, indicating a stress-induced mobili-zation of energy reserves. These results clearly show that thewater-soluble fraction of gasoline can cause important alterationsin P. lineatus. Financial support: CNPq.

doi:10.1016/j.cbpa.2007.06.174

16.9. The consequences and causes of individual variationin fish

Sloman, K.School of Biological Sciences, University of Plymouth, UK

katherine.sloman@plymouth.ac.uk

The behavioural and physiological traits of an individual reflectthe inheritance of a specific genotype and yet can be stronglyinfluenced by early environmental experiences. Within salmonidpopulations, individual variation in physiological and behaviouralparameters leads, in particular, to differences in competitive abilitywith intraspecific competition becoming visible at first feeding.Differential acquisition of food as a result of individual variation incompetitive ability can then go on to magnify individualdifferences within populations and strengthen social hierarchies.Here, I will discuss how the physiology of individuals is signi-ficantly affected by social status and how this relationship isdependent on the abiotic environment. The individual differencesin behaviour and physiology that are associated with competitiveability in salmonids can affect their responses to aquatic toxicants,

S68 Abstracts / Comparative Biochemistry and Physiology, Part A 148 (2007) S66–S79