期刊
ENVIRONMENTAL SCIENCE & TECHNOLOGY
卷 50, 期 16, 页码 8827-8839出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.est.6b00861
关键词
-
资金
- Australian Synchrotron Research Program [ASRP-644]
- U.S. Department of Energy, Basic Energy Sciences, Office of Science [DE-AC02-06CH11357]
Metal toxicity to aquatic organisms depends on the speciatiOn of the metal and its binding to the critical receptor site(s) (biotic ligand) of the organism. The intracellular- nature of the biotic ligand for Cu in microalgal cells was investigated using the high elemental sensitivity of microprobe synchrotron radiation X-ray fluorescence (SR-XRF) and X-ray absorption near-edge spectroscopy (XANES): The marine microalgae, Ceratoneis closterium, Phaeodactylum, tricornutum, and Tetraselmis sp. were selected based on their varying sensitivities to Cu (72-h 50% population growth inhibitions of 8-47 mu g Cu/L). Intracellular Cu in control cells was similar for all three species (2.5-3.2 X 10(-15) g Cu/cell) and increased 4fold in C. closterium and Tetraselmis sp. when exposed to copper, but was unchanged- in P. tricornutum (72-h exposure to 19, 40, and 40 mu g Cu/L, respectively). Whole cell microprobe SR-XRF identified endogenous Cu in the central compartment (cytoplasm) of control (unexposed) cells. After Cu exposure, Cu was colocated- with organelles/granules dense in F, S, Ca, and Si and this was clearly evident in thin sections of Tetraselmis sp. XANES indicated coexistence of Cu(I) and Cu(II) in control and Cu-exposed cells, with the Cu ligand (e.g., phytochelatin) in P. tricornutum different from that in C. closterium and Tetraselmis sp. This study supports the hypothesis that Cu(II) is. reduced to- Cu(I) and that polyphoSphate bodies and phytOchelatins play a significant role in the internalization and detoxification of Cu in marine microalgae.
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