A simple method to detect Borrelia burgdorferi sensu lato proteins in different sub-cellular compartments by immunofluorescence.

Spirochaetes constitute a unique phylum of bacteria, many of which cause severe clinical diseases. Borrelia burgdorferi sensu lato (B. burgdorferi s.l.)-the primary agent of Lyme borreliosis (LB)-is a quintessential member of this poorly understood phylum and the leading cause of tick-borne illness throughout most of the northern hemisphere. Despite its importance in human health, we lack a fundamental understanding of how B. burgdorferi s.l. is able to accomplish basic physiological tasks, such as DNA replication/segregation, and cell elongation or division. Recent advances in molecular tools to probe these essential cellular processes are great strides forward but require genetic manipulation. The latter is important since not all agents of LB are genetically tractable. Here, we describe a single method that is capable of fluorescently labeling B. burgdorferi s.l. proteins in different sub-cellular compartments. A comparative analysis of six different methods indicates that our optimized procedure outperforms all others and is the first to localize a cytoplasmic protein in B. burgdorferi s.l. by immunofluorescence. We contend that this strategy could be easily adapted to study the localization of any protein, in many Borrelia genospecies, information that will yield functional insights into the complex biology of this fascinating group of bacteria. In addition, it may provide new avenues of research in both in situ studies and in Lyme diagnostics.