title: Confocal laser scanning microscopy coupled to a spectrofluorometric detector as a rapid tool for determining the in vivo effect of metals on phototrophic bacteria.
abstract: In this paper, we determine for the first time the in vivo effect of heavy metals in a phototrophic bacterium. We used Confocal Laser Scanning Microscopy coupled to a spectrofluorometric detector as a rapid technique to measure pigment response to heavy-metal exposure. To this end, we selected lead and copper (toxic and essential metals) and Microcoleus sp. as the phototrophic bacterium because it would be feasible to see this cyanobacterium as a good biomarker, since it covers large extensions of coastal sediments. The results obtained demonstrate that, while cells are still viable, pigment peak decreases whereas metal concentration increases (from 0.1 to 1 mM Pb). Pigments are totally degraded when cultures were polluted with lead and copper at the maximum doses used (25 mM Pb(NO(3))(2) and 10 mM CuSO(4)). The aim of this study was also to identify the place of metal accumulation in Microcoleus cells. Element analysis of this cyanobacterium in the above mentioned conditions determined by Energy Dispersive X-ray microanalysis (EDX) coupled to Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), shows that Pb (but not Cu) accumulates externally and internally in cells.
authors: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain. mireia.burnat@uab.cat
authors: Mireia
authors: M
authors: Burnat
authors: Elia
authors: E
authors: Diestra
authors: Isabel
authors: I
authors: Esteve
authors: Antonio
authors: A
authors: Solé
mesh_terms: D019327:Copper Sulfate / Q000378:metabolism / Q000633:toxicity*; D000458:Cyanobacteria / Q000187:drug effects* / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D004784:Environmental Monitoring / Q000379:methods*; D007854:Lead / Q000378:metabolism / Q000633:toxicity*; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009566:Nitrates / Q000378:metabolism / Q000633:toxicity*; D013050:Spectrometry, Fluorescence
chemical_list: D009566:Nitrates; D007854:Lead; C017461:lead nitrate; D019327:Copper Sulfate