Use este identificador para citar ou linkar para este item: http://repositorio.inpa.gov.br/handle/123/839
Título: Biochemical adjustments to hypoxia in Amazon cichlids
Autor(es): Vera Maria Fonseca de Almeida e Val
Izeni Pires Farias
Maria de Nazaré Paula da Silva
Wallice Paxiuba Duncan
Adalberto Luis Val
Assunto: Adaptação ao Ambiente
Amazônia
Ciclídeos
ISSN: 0100-879X
Revista: Brazilian Journal of Medical and Biological Research
Volume: 28
Resumo: The isozyme distribution of cichlid lactate dehydrogenase (LDH) is related to species environmental preferences. Cichlasoma amazonarum occurs in different environments and presents LDH tissue distribution patterns that correlate with oxygen tension at the capture location. Cichlasoma amazonarum was exposed to long-term severe hypoxia (51 days at 36.4 +/- 5.9 mmHg), tissue LDH isozyme distribution was analyzed by electrophoresis and enzyme activities were measured by monitoring the oxidation of NADH as pyruvate was reduced to lactate. The exposure of Cichlasoma amazonarum to long-term severe hypoxia resulted in changes in the tissue distribution of LDH isozymes. The major changes in response to hypoxia occurred in heart, liver and brain: isozyme A4 was activated in heart and brain, whereas isozyme B4 was activated in liver. The most significant quantitative change occurred in brain LDH of hypoxia-exposed animals which adopted muscle type kinetics, reflecting a new LDH isozyme distribution. LDH activity was significantly reduced (P < 0.05) in animals exposed to hypoxia (N = 8), suggesting an overall LDH suppression. Pyruvate inhibition decreased in all hypoxia-exposed tissues. Thus, the ability of Cichlasoma amazonarum to regulate LDH tissue expression according to oxygen availability allows the animal to survive chronic hypoxic environments. This phenotypic plasticity may occur in other hypoxia-tolerant fish species.
URI: http://repositorio.inpa.gov.br/handle/123/839
ISSN: 0100-879X
Local de publicação: Brasil
Aparece nas coleções:Coordenação de Biodiversidade (CBIO)

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