Correlative light and electron microscopy (CLEM) allows us to combine wide field images collected from light microscopy with the high resolution of electron microscopy. CLEM is especially convenient for visualization of rare and dynamic events, which cannot be followed by electron microscopy on its own, such as membrane trafficking, signalling and cell division. Although the use of CLEM in host-parasite research is not very common today (Loussert et al., 2012), it fulfils all criteria to become a method of choice for visualization/investigation of infectious diseases where only a small number of pathogenic organisms is required to cause illness. We apply correlative fluorescence scanning electron microscopy to image the spirochete B. burgdorferi, the causative agent of Lyme disease, which is the most common tick-borne infection in the Western world. We examine and more fully characterize the events involved in the progression of B. burgdorferi through the tick salivary glands, using a genetically modified strain carrying the GFP reporter gene. Unlike the mode of penetration through the tick gut (Dunham-Ems et al., 2009), the way how B. burgdorferi transverse the salivary gland barrier remains unclear. Our results help to possibly shed new light on the adaptation of the Lyme disease spirochete within the tick vector and its transmission to a new mammalian host.
1. S.M. Dunham-Ems, M.J. Caimano, U. Pal, et al., J. Clin. Invest. 119 (2009), p. 3652.
2. C. Loussert, C. L. Forestier and B. M. Humbel, Methods Cell Biol. 111 (2012), p. 59.
The study is supported by the Technology Agency of the Czech Republic (TE01020118).