It would be interesting to address these issues in our future work. Camelysin and InhA might not be essential for the growth or sporulation. However, when B. thuringiensis invaded an insect host, InhA was able to specifically cleave antibacterial peptides that could kill B. thuringiensis, favoring the subsistence of B. thuringiensis in the insect host body. Nisnevitch et al. (2010) reported that camelysin could activate the protoxins Cyt1Aa and

Cyt2Ba produced by Bti. It was reported that an alkaline protease A and a neutral protease A-deficiency strain could increase yields of certain full-length crystal proteins in B. thuringiensis (Tan ZD1839 molecular weight & Donovan, 2001). Charlton et al. (1999) and Grandvalet et al. (2001) reported that a homologous InhA protein existed in an active form on the exosporium of B. cereus. This suggests that the presence of camelysin, InhA or other endogenous proteases may be important for B.

thuringiensis virulence at the sporulation phase. This work was supported by grants from the National Natural Science Foundation of China (Nos 30870064, 30970066 and 31070006) and the Youth Foundation of Hunan Normal University (30901). “
“NopT1 selleck compound and NopT2, putative type III effectors from the plant symbiotic bacterium Bradyrhizobium japonicum, are predicted to belong to a family of YopT/AvrPphB effectors, which are cysteine proteases. In the present study, we showed that both NopT1 and NopT2 indeed possess cysteine protease activity. When overexpressed in Escherichia coli, both NopT1 and NopT2 undergo autoproteolytic processing which is largely abolished in the presence of E-64, a papain family-specific inhibitor. Mutations of NopT1 disrupting

either the catalytic triad or the putative autoproteolytic site reduce or markedly abolish the protease activity. Autocleavage likely occurs between residues K48 and M49, though another potential cleavage site is also possible. NopT1 also elicitis HR-like cell death about when transiently expressed in tobacco plants and its cysteine protease activity is essential for this ability. In contrast, no macroscopic symptoms were observed for NopT2. Furthermore, mutational analysis provided evidence that NopT1 may undergo acylation inside plant cells and that this would be required for its capacity to elicit HR-like cell death in tobacco. Bradyrhizobium japonicum (henceforth B. japonicum or Bja) is a Gram-negative soil bacterium capable of fixing atmospheric nitrogen in symbiosis with specific leguminous plants (e.g. Glycine max). Although the genetic basis of nodulation has been extensively studied, recent findings indicate that the type III secretion system (T3SS) plays a role in symbiosis. Genes encoding T3SSs and putative effector proteins have been identified in several but not all rhizobia by genome sequencing, such as B. japonicum USDA110, Rhizobium sp. NGR234, Mesorhizobium loti MAFF303099, Sinorhizobium fredii HH103, and S.