title: Spatial Pattern of Copper Phosphate Precipitation Involves in Copper Accumulation and Resistance of UnsaturatedPseudomonas putidaCZ1 Biofilm.
abstract: Bacterial biofilms are spatially structured communities that contain bacterial cells with a wide range of physiological states. The spatial distribution and speciation of copper in unsaturatedPseudomonas putidaCZ1 biofilms that accumulated 147.0 mg copper per g dry weight were determined by transmission electron microscopy coupled with energy dispersive X-ray analysis, and micro-X-ray fluorescence microscopy coupled with micro-X-ray absorption near edge structure (micro-XANES) analysis. It was found that copper was mainly precipitated in a 75 μm thick layer as copper phosphate in the middle of the biofilm, while there were two living cell layers in the air-biofilm and biofilm-medium interfaces, respectively, distinguished from the copper precipitation layer by two interfaces. The X-ray absorption fine structure analysis of biofilm revealed that species resembling Cu₃(PO₄)₂ predominated in biofilm, followed by Cu-Citrate- and Cu-Glutathione-like species. Further analysis by micro-XANES revealed that 94.4% of copper were Cu₃(PO₄)₂-like species in the layer next to the air interface, whereas the copper species of the layer next to the medium interface were composed by 75.4% Cu₃(PO₄)₂, 10.9% Cu-Citrate-like species, and 11.2% Cu-Glutathione-like species. Thereby, it was suggested that copper was initially acquired by cells in the biofilm-air interface as a citrate complex, and then transported out and bound by out membranes of cells, released from the copper-bound membranes, and finally precipitated with phosphate in the extracellular matrix of the biofilm. These results revealed a clear spatial pattern of copper precipitation in unsaturated biofilm, which was responsible for the high copper tolerance and accumulation of the biofilm.
authors: Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Zhejiang 310058, P.R. China.|Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, P.R. China.
authors: Guangcun
authors: G
authors: Chen
authors: Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Zhejiang 310058, P.R. China.|Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P.R. China.
authors: Huirong
authors: H
authors: Lin
authors: Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Zhejiang 310058, P.R. China.
authors: Xincai
authors: X
authors: Chen
mesh_terms: D018441:Biofilms; D011232:Chemical Precipitation; D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism*; D016958:Pseudomonas putida / Q000737:chemistry / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D010710:Phosphates; D003300:Copper
keywords: Pseudomonas putida CZ1; copper phosphate; spatial pattern; speciation; unsaturated biofilm