Using super-resolution microscopy, a team of researchers are now able to see in detail the machinery used by bacteria to build their outer membranes. Understanding how microbes build and maintain their outer surface which is presented to the immune system is key to the fight against antimicrobial-resistance “superbugs.” The paper describing the custom-built microscope and the findings was published in Cell Reports.
The research team at Monash University built a super-resolution microscope and customized it to be able to visualize individual molecules in a single bacterium. It was already known that the β-barrel assembly machinery (BAM) complex is responsible for several functions in Gram-negative bacteria including synthesizing and inserting β -barrel proteins into the outer membrane. However, the mechanism used by BAM was not well understood. Using dSTORM methodology to view the BAM complex in situ, the team discovered that BAM complexes sit together within individual areas and that these areas or precincts are distributed across the bacterial cell surface. The team observed that BAM complexes were ~200nm apart and that the individual BAM subunits, BamA and BamB, interact with other subunits in neighboring complexes. It was also observed that the BAM complex precincts swell with membrane protein synthesis indicating that BAM is involved in protein assembly.
The five-year project was accomplished with the effort of multiple specialists including biochemists, microscopists, physicists, biologists and computer programmers. Professor Trevor Lithgow, the team leader, believes they’re visualizing what had never been seen before in what “will provide researchers with key knowledge to disarm superbug resistance to the immune system."