In:
Journal of Phycology, Wiley, Vol. 50, No. 4 ( 2014-08), p. 665-674
Abstract:
We investigated the effects of zinc or lead on growth and on exudation of fluorescent dissolved organic matter ( FDOM ) by the marine toxic dinoflagellate A lexandrium catenella (Whedon & Kofoid) Balech. The species was exposed to increasing free zinc (1.34 × 10 −7 M–3.98 × 10 −6 M) or lead (5.13 × 10 −9 M–1.82 × 10 −7 M) concentra‐tions. Low metal levels ([ Zn 2+ ] = 1.34 × 10 −7 M; [ Pb 2+ ] = 5.13 × 10 −9 M) had no effect on cell growth. Toxic effects were observed from higher metal contamination ([ Zn 2+ ] = 3.98 × 10 −6 M; [ Pb 2+ ] = 6.54 × 10 −8 M), as a conversion of vegetative cells into cysts. Analysis of the released FDOM by three‐dimensional (3‐D) fluorescence spectroscopy was achieved, using the parallel factor analysis ( PARAFAC ). The PARAFAC modeling revealed four components associated with two contributions: one related to the biological activity; the other linked to the organic matter decomposition in the culture medium. The C1 component combined a tryptophan peak and characteristics of humic substances, whereas the C2 component was considered as a tryptophan protein fluorophore. The two others C3 and C4 components were associated with marine organic matter production. Relea‐sed fluorescent substances were induced by low ([ Zn 2+ ]= 1.34 × 10 −7 M; [ Pb 2+ ] = 5.13 × 10 −9 M) and moderate ([ Zn 2+ ] = 6.21 × 10 −7 M; [ Pb 2+ ] = 2.64× 10 −9 M) metal concentrations, suggesting the activation of cellular mechanisms in response to metal stress, to exudate FDOM that could complex metal cations and reduce their toxicity toward A . catenella cells.
Type of Medium:
Online Resource
ISSN:
0022-3646
,
1529-8817
DOI:
10.1111/jpy.2014.50.issue-4
Language:
English
Publisher:
Wiley
Publication Date:
2014
detail.hit.zdb_id:
281226-5
detail.hit.zdb_id:
1478748-9
SSG:
12
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