compared with the glycoside hydrolase family amylomaltases from other bacteria, plants, and archaea. Because MalQ and maltose transport proteins have been implicated in expression of virulence factors in V. cholerae and streptococci, respectively (Lång et al., 1994; Shelburne et al., 2006), presumably to relay information about the environment,
we assayed whether malQ has a similar role in B. burgdorferi. Neither the malQ mutation nor varying carbohydrates available affected the expression of outer surface lipoprotein C (data not shown), which is essential for MK-2206 supplier transmission or mammalian infection (Grimm et al., 2004; Pal et al., 2004). While our data suggest that MalQ does not have an essential role in disaccharide utilization in vitro, we hypothesized that MalQ
may be important in the enzootic cycle for metabolism or gene regulation in vivo. Therefore, we assayed the malQ::aadA Small molecule library ic50 mutant strain in the experimental tick–mouse model. Wild-type, malQ::aadA, and complemented strains were needle-inoculated into mice; ear biopsies were collected 3 weeks after injection, cultured in BSK II, and examined for spirochetes by dark-field microscopy. In addition, ear, ankle, and bladder tissues were dissected and cultured for B. burgdorferi at 5 weeks postinoculation. The malQ mutant was infectious by needle inoculation and successfully disseminated to the ear, ankle, and bladder of the mice (Table 2). To examine the role of MalQ in B. burgdorferi acquisition, naive I. scapularis larvae were allowed to feed to repletion on mice infected with wild-type 297, malQ::aadA, or complemented strains. Five to 10 days after feeding to repletion, PCR analysis revealed that larvae acquired B. burgdorferi from infected mice independent of the presence of malQ (seven of seven ticks were infected with each strain). Larvae Isotretinoin that had
fed to repletion on infected mice were allowed to molt into nymphs to examine whether MalQ functions in tick persistence. After 3 to 4 weeks, five nymphs infected with each strain were then fed to repletion on naive mice. About 7 days after feeding to repletion, the midguts were dissected and processed for immunofluorescence microscopy using anti-Borrelia antibodies (green) and wheat germ agglutinin-AlexaFluor® 594 that stains tick cells (red). All midguts examined contained B. burgdorferi at similar densities by immunofluorescence microscopy (Fig. 4), suggesting that survival during molting and persistence in nymphs following the blood meal does not require MalQ. Although mouse infection by needle inoculation was malQ independent, the natural route of transmission is by tick bite. Nymphs infected with wild-type, malQ::aadA, or complemented strains were allowed to feed to repletion on naive mice to test whether transmission of B. burgdorferi by tick bite requires malQ. Five nymphs infected with each strain were fed on three separate mice. Three weeks after tick feeding, ear biopsies were taken, cultured and screened for B.