, 2003). BtkB may also be involved in the heat-shock response. After reaching the maximum density, btkB mutant began to decrease rapidly. The cellular reversal of M. xanthus gliding is regulated by chemotaxis homologues (Shi et al., 2000). btkB mutant cells reversed

direction selleck inhibitor approximately every 4.2 min on average, which was similar to that of wild-type cells (4.6 min). The wild-type and btkB mutant strains (9 × 109 cells mL−1) were cultured on CF agar. The wild-type cells moved to aggregation centers and then formed mound-shaped fruiting bodies by 48–72 h on CF agar. After 3 days of development, the wild-type strain had produced dark fruiting bodies containing refractile sonication- and heat-resistant spores, while the btkB mutant strain had produced I-BET-762 datasheet only translucent aggregates that were not

filled with refractile spores (Fig. 5a). The btkB mutant cells formed fruiting bodies about 24 h later than the wild-type strain. The viable spore numbers produced by the mutant at 4 and 5 days were approximately 20–30% those of the wild-type strain; however, the final yield of viable spores for btkB mutant at 7 days was similar to that of the wild-type strain (Fig. 5b). Gram-positive type of M. xanthus BY kinase, BtkA, is required for the formation of mature spores (Kimura et al., 2011), while BtkB is not essential to form mature spores. The btkB mutant produced a high level of yellow pigment during fruiting body formation (data not shown). The fruiting bodies of btkB mutant were harvested by gently scraping the surface with a bacteria spreader and were suspended in TM buffer. After centrifugation, the supernatant had a UV absorption maximum of 380 nm. This is in agreement with the major yellow pigment, DKxanthene-534, of M. xanthus DK1622 (λmax = 379 nm),

which is essential for developmental sporulation (Meiser et al., 2006). On the other hand, when vegetative cells were cultured with 0.5 M glycerol in CYE medium, the mutant cells sporulated at the same rate as wild-type cells Glutathione peroxidase (data not shown). EPS is an important component for social behaviors in M. xanthus, including gliding motility and fruiting body formation. EPS is the binding target for type IV pili in S-motility (Li et al., 2003) and forms a scaffold within the fruiting body structure (Shimkets, 1986; Lux et al., 2004). EPS production was analyzed quantitatively by the binding of Congo red and trypan blue. Exponentially growing cells (8 × 108 cells mL−1) in CYE medium were used for the assays, and the percentage of dye bound by cells was determined. btkB mutant cells bound Congo red and trypan blue at lower levels than wild-type cells. The btkB mutant bound 23.8 ± 0.2% and 7.1 ± 1.3% of Congo red and trypan blue, respectively, compared with 40.3 ± 0.1% and 29.8 ± 0.3% for the wild type. We also determined the amount of EPS from broken cell pellets. As shown in Fig.