Zernike phase contrast cryo-electron tomography of whole bacterial cells.
Cryo-electron tomography (cryo-ET) provides three-dimensional (3D) structural information of bacteria preserved in a native, frozen-hydrated state. The typical low contrast of tilt-series images, a result of both the need for a low electron dose and the use of conventional defocus phase-contrast imaging, is a challenge for high-quality tomograms. We show that Zernike phase-contrast imaging allows the electron dose to be reduced. This limits movement of gold fiducials during the tilt series, which leads to better alignment and a higher-resolution reconstruction. Contrast is also enhanced, improving visibility of weak features. The reduced electron dose also means that more images at more tilt angles could be recorded, further increasing resolution.
Division of Pediatric Infectious Diseases, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, GA 30322, United States.
Ricardo C
RC
Guerrero-Ferreira
Division of Pediatric Infectious Diseases, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, GA 30322, United States. Electronic address: erwrigh@emory.edu.
Elizabeth R
ER
Wright
D001419:Bacteria / Q000648:ultrastructure*; D020285:Cryoelectron Microscopy / Q000295:instrumentation* / Q000379:methods; D055032:Electron Microscope Tomography / Q000295:instrumentation* / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods; D008858:Microscopy, Phase-Contrast / Q000295:instrumentation* / Q000379:methods
Bacteria; Caulobacter crescentus; Cryo-electron tomography (cryo-ET); Defocus phase contrast (DPC); Vibrio vulnificus; Zernike phase contrast (ZPC)