5. An original super-resolution imaging mode for ellipsoidal Bacillus subtilis spores by Julia Manetsburger and Eric Rees
Spores of Bacillus subtilis are encapsulated by a multi-layered protein coat which provides these micro-organisms with remarkable durability such as the ability to survive exposure to boiling water. Fluorescent fusion proteins provide one of the only methods for accurately labelling specific proteins (top left image). The diffraction-limited resolution of traditional fluorescence microscopy is insufficient to distinguish the order of the various concentric protein layers in the spore coat. We have developed an original super-resolution imaging technique which uses modern computational maths to evaluate the geometry of each spore based on its image data. The true fluorescence density of the spore coats can then be visualised by image reconstruction (the main image shows one protein distribution with colour mapped density), and protein layer order can be distinguished. The tendency of some proteins to localise more densely as the spore poles can also be measured by this method.