We were unable to find any of our candidate chitin utilization genes upon examination of differentially

regulated genes identified in their study. It is possible that starvation for GlcNAc is necessary for the induction of these genes, a condition that was not tested by Caimano et al. In this study we provide evidence that B. burgdorferi can selleck products utilize GlcNAc oligomers and chitin in the absence of free GlcNAc, and we show that chitobiose transport via chbC is required for utilization of these substrates. A previous report suggested chbC is not required for maintenance or transmission of the organism between ticks and mice [15]. However, these studies were conducted in a controlled laboratory environment using pathogen-free ticks and mice. It is possible chbC plays a role in infection

in a natural setting by providing a competitive advantage to spirochetes in colonizing ticks that are often colonized with more than one microorganism. In addition, chbC is required for obtaining sequestered GlcNAc during Paclitaxel research buy second exponential phase growth in selleck screening library vitro which most likely comes from glycoproteins or glycosaminoglycans, so there may also be a role for this transporter in the mammal. However, it is also possible that chitinase activity, rather than chitin utilization, is required for transmission, as chitinase activity may be important for penetration of the peritrophic membrane and colonization of the tick midgut. In this instance, the chbC gene may be retained, but chitobiose uptake and utilization may be of secondary importance. Conclusions In this study

we provide evidence of an inherent chitinase activity in rabbit serum, a component buy Docetaxel of the B. burgdorferi growth medium, BSK-II. We inactivated this activity by boiling, and showed that cells can utilize GlcNAc oligomers and chitin as a source of GlcNAc in the presence of boiled serum or a lipid supplement. In addition, we demonstrated that transport of chitobiose via the chitobiose transporter, chbC, is required for chitin utilization by this organism. Finally, delayed growth of an rpoS mutant on chitohexose suggests that this alternative sigma factor is involved in the regulation of chitin utilization. Methods Bacterial strains and culture conditions Bacterial strains and plasmids described in this work are listed in Table 2. B. burgdorferi strains were maintained in modified BSK-II [36] supplemented with 7% rabbit serum and any necessary antibiotics (see Table 2). BSK-II was modified by replacing 10× CMRL-1066 with 10× Media 199 (Invitrogen Corp.; Carlsbad, CA). Some experiments were conducted with boiled rabbit serum to inactivate the inherent chitinase activity. Serum was diluted 2-fold in sterile deionized water, incubated in a boiling water bath for 2 min and allowed to cool to room temperature.