Du är här

Glutathione transferase activity and oocyte development in copepods exposed to toxic phytoplankton

Författare:
Publiceringsår: 2009
Språk: Engelska
Sidor: 395-406
Publikation/Tidskrift/Serie: Harmful Algae
Volym: 8
Nummer: 3
Dokumenttyp: Artikel
Förlag: Elsevier Science Bv

Sammanfattning

Organisms present a series of cellular mechanisms to avoid the effects of toxic compounds. Such mechanisms include the increase in activity of detoxification enzymes e.g., 7-ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST)I, which could explain the low retention of ingested toxins generally observed in copepods. In addition, decreasing gross growth efficiency (GGE) of copepods with increasing concentration of toxic diets could be caused either by a high expenditure coping with toxins (e.g., increase in the activity of detoxification enzymes) or by a deterioration of reproductive tissues. To assess the effect of toxic phytoplankton on the activity of detoxification enzymes and on oocyte maturation of Acartia tonsa and Temora longicornis, feeding and egg production experiments were carried out with a variety of toxic diets and an adequate non-toxic food control (Rhodomonas spp.) all provided as single species diets. Toxic diets included the nodularin-producing cyanobacterium Nodularia spumigena, the dinoflagellates Alexandrium minutum, and A. tamarense, which contained Paralytic Shellfish Poisoning (PSP) toxins, the dinoflagellate Prorocentrum lima with Diarrhetic Shellfish Poisoning (DSP) toxins and the haptophyte Prymnesium parvum, which produces ichtyotoxins with haemolytic activity. Feeding on toxic diets was lower than on Rhodomonas spp., except for A. minutum and A. tamarense. In addition, toxic diets negatively affected reproduction in both copepod species with the production of oocytes and oocyte development impaired with A. minutum and N. spumigena. While the negative effect of N. spumigena seemed to be connected to gonad atresia likely caused by severe food limitation (starvation), the negative effect of A. minutum could have been either caused by a direct effect of saxitoxins or nutritional inadequacy on oocyte production. We could not detect EROD activity in the copepods, while the activity of GST was generally higher with the non-toxic food control and positively related to the feeding and egestion rates, suggesting relation to feeding conditions rather than to exposure to toxic diets. No relationship was found between GGE and CST activity. Our results refute the hypothesis that toxic diets, provided at ecologically relevant levels, would induce cellular mechanisms in copepods regarding GST activity. GST activity thus seems to play no role in detoxification of copepods confronted with toxic phytoplankton. Toxin detoxification and its cost for copepods still remain an open question. (C) 2008 Elsevier B.V. All rights reserved.

Disputation

Nyckelord

  • Biology and Life Sciences
  • longicornis
  • Toxic phytoplankton
  • Temora
  • Oocyte development
  • Nodularia spumigena
  • S-transferase
  • Glutathione
  • Detoxification
  • Acartia tonsa
  • Alexandrium minutum

Övrigt

Published
Yes
  • ISSN: 1568-9883

Box 117, 221 00 LUND
Telefon 046-222 00 00 (växel)
Telefax 046-222 47 20
lu [at] lu [dot] se

Fakturaadress: Box 188, 221 00 LUND
Organisationsnummer: 202100-3211
Om webbplatsen

LERU logo U21 logo