Most observations of spirochetes come from cultivated microbes or rich animal systems. This is because of the small size of these bacteria and the technical difficulties associated with resolving them in complex environmental samples. This movie shows bacteria from a soil sample swimming amongst soil particles and other soil microbes. Spirochetes are usually only observed after culture in vitro or from animal environments like guts (5). However, they are widely distributed in nature and presumably play an important role as free living microbes in environments such as soil. For example, analysis of soil communities show spirochetes contribute approximately 1% of diversity (6), a large amount for such a complex ecosystem. Spirochetes are near the limits of optical microscopy (with some dimensions of approximately 1 µm) and so are hard to see, especially when the environmental context of samples is preserved, including soil particles and large protozoa. Bulky samples must contain many planes of foci, allowing the very small spirochetes to swim out of view with ease. This movie shows spirochetes in the context of their fellow microbes and their natural soil environment.
Figure 1: Environmental Spirochetes (video).
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