title: In Situ Molecular Imaging of the Biofilm and Its Matrix.
abstract: Molecular mapping of live biofilms at submicrometer resolution presents a grand challenge. Here, we present the first chemical mapping results of biofilm extracellular polymeric substance (EPS) in biofilms using correlative imaging between super resolution fluorescence microscopy and liquid time-of-flight secondary ion mass spectrometry (TOF-SIMS). Shewanella oneidensis is used as a model organism. Heavy metal chromate (Cr2O72-) anions consisting of chromium Cr(VI) was used as a model environmental stressor to treat the biofilms. Of particular interest, biologically relevant water clusters have been first observed in the biofilms. Characteristic fragments of biofilm matrix components such as proteins, polysaccharides, and lipids can be spatially imaged. Furthermore, characteristic fatty acids (e.g., palmitic acid), quinolone signal, and riboflavin fragments were found to respond after the biofilm is treated with Cr(VI), leading to biofilm dispersal. Significant changes in water clusters and quorum sensing signals indicative of intercellular communication in the aqueous environment were observed, suggesting that they might result in fatty acid synthesis and inhibition of riboflavin production. The Cr(VI) reduction seems to follow the Mtr pathway leading to Cr(III) formation. Our approach potentially opens a new avenue for mechanistic insight of microbial community processes and communications using in situ imaging mass spectrometry and super resolution optical microscopy.
authors.affiliation: Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University , 637551, Singapore.|Interdisciplinary Graduate School (IGS), Nanyang Technological University (NTU) , 639798, Singapore.|Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99354, United States.
authors.forename: Yuanzhao
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Environmental and Molecular Science Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Yufan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99354, United States.
authors.forename: Juan
authors.initials: J
authors.lastname: Yao
authors.affiliation: Environmental and Molecular Science Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Craig
authors.initials: C
authors.lastname: Szymanski
authors.affiliation: Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99354, United States.
authors.forename: James
authors.initials: J
authors.lastname: Fredrickson
authors.affiliation: Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99354, United States.
authors.forename: Liang
authors.initials: L
authors.lastname: Shi
authors.affiliation: Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University , 637551, Singapore.|School of Civil and Environmental Engineering, Nanyang Technological University (NTU) , 639798, Singapore.
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.affiliation: Environmental and Molecular Science Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Zihua
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99354, United States.
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Yu
mesh_terms: D018441:Biofilms / Q000187:drug effects; D002857:Chromium / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D057054:Molecular Imaging; D020592:Shewanella / Q000737:chemistry* / Q000378:metabolism; D018629:Spectrometry, Mass, Secondary Ion
chemical_list: D002857:Chromium