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| Titel: |
Aspects of copper tolerance and toxicity in Amphora coffeaeformis |
| Auteur: |
Robinson, Maurice G. Brown, Leslie N. Quenneville, Melanie L. Hall, Beverley D. |
| Verschenen in: |
Biofouling |
| Paginering: | Jaargang 5 (1992) nr. 4 pagina's 261-276 |
| Jaar: |
1992-05 |
| Inhoud: |
Measurements of photosynthesis, respiration, electron transport activity and ATP were used to locate the site(s) of copper toxicity in the fouling diatom, Amphora coffeaeformis. Results of this and previous research suggest that, except at very high concentrations (≥ 5 × 10-6 M), ionic copper does not target these processes, but rather one which occurs at or near the plasmalemma. This may reflect a reduced ability of ionic copper to cross the membranes of the chloroplasts and mitochondria, and possibly the plasmalemma as well. In contrast, copper bound to HQO (8-hydroxyquinoline) or HQA (8-hydroxyquinaldine) was highly toxic to electron transport and ATP production, although the ligands alone had no effect on either process. This supports a membrane-carrier role for HQO and HQA, which give copper access to internal mitochondrial and possibly chloroplast membranes. In a second set of experiments, A. coffeaeformis cells were treated with enzymes in order to elucidate external copper tolerance mechanisms. Cells treated with the polysaccharidase, β-glucuronidase, became more sensitive to copper, whereas those treated with the protease, trypsin, showed improved growth and no increase in sensitivity to copper. This supports a polysaccharide-based tolerance mechanism. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 2 van 9 gevonden artikelen
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