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| Ramirez-Gil,H.; Feldberg,E.; Almeida-Val,V.M.F.; Val,A.L.. |
| Karyological characteristics, i.e., diploid number, chromosome morphology and nucleolus organizer regions (NORs), biochemical characteristics, i.e., electrophoretic analysis of blood hemoglobin and the tissue enzymes lactate dehydrogenase (LDH), malate dehydrogenase (MDH), alcohol dehydrogenase (ADH), and phosphoglucose isomerase (PGI), and physiological characteristics, i.e., relative concentration of hemoglobin and intraerythrocytic concentrations of organic phosphates were analyzed for the species Callophysus macropterus collected from Marchantaria Island (white water system - Solimões River) and Anavilhanas Archipelago (black water system - Negro River). Karyological and biochemical data did not reveal significant differences between specimens... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Callophysus; Fish; Amazon; Population genetics; Adaptation. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001100014 |
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| Matsuo,A.Y.; Val,A.L.. |
| The present study analyzes Na+ and K+ disturbances caused by low pH in two catfish species from the Amazon River. Corydoras adolfoi inhabits ion-poor, black-stained, low pH (3.5-4.0) waters, while C. schwartzi is native to ion-rich waters at circumneutral pH. Fish were exposed to pH 3.5 Ca2+-free, and Ca2+-enriched (~500 µmol/l) water to determine the protective effects of calcium. Net Na+ and K+ fluxes were measured in the water collected from the fish experimental chambers. C. adolfoi was unable to control the Na+ efflux at low pH, exhibiting Na+ loss up to -594 ± 84 nmol g-1 h-1 during the first hour. After 3 and 6 h, net Na+ flux increased by 7- and 23-fold, respectively. In C. schwartzi, at pH 3.5, the initial high Na+ loss (-1,063 ± 73 nmol g-1 h-1)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Low pH; Calcium; Blackwater; Net Na+ and K+ flux; Amazon; Catfish. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000300012 |
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