Of microscopes and microbes; novel applications of optical microscopy to microbiology

The development of optical microscopy has been traditionally driven by the needs of eukaryotic cell biology. Therefore, there are a number of unmet requirements for the application of advanced microscopy techniques to the field of microbiology. Conventional techniques, such as widefield epi-fluorescence and confocal laser scanning microscopy, are common-place in most laboratories, however these methods have trade-offs in terms of their attainable resolution and limited imaging volume. Here we present the application of several optical microscopy methods with the aim addressing the unmet needs of the field; increasing spatial resolution and sampling volume. We demonstrate the use of Interference Reflection Microscopy (IRM) for investigating the morphology and gliding motility of Myxococcus xanthus. This label-free technique provides super-resolution in the axial plane where changes in cell shape on the order of 100 nm can be detected in live cells. Using IRM we show novel insights into the gliding behaviour of these bacteria. We also present the application of the Mesolens to microbiology. The Mesolens is a large optical microscope with the unique combination of a low magnification