The major obstacle to studying membranes in living cells has been that high-resolution physical methods used to investigate membrane structure are not compatible with living organisms. To overcome this obstacle, Nickels et al. employed a new in vivo approach that allows membrane structure to be observed directly in the gram-positive bacterium Bacillus subtilis. This approach relies on tuning the isotopic content of hydrogen within the membrane (and other parts of the bacterium) to generate neutron scattering spectra exclusively from the membrane. The image shows a cross-section of the B. subtilis cell wall (top), membrane and cytoplasm (bottom), illustrating the complex composition and organization of a living cell The in vivo labeling strategy employed by Nickels et al. revealed the detailed structure of the cell membrane (central blue and red band).

Image Credit: X. Cheng and M.A. Matheson