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Research has been conducted on produced by Streptomyces atroolivaceus S-140 leinamycin. The study of leinamycin biosynthesis has been performed, and the generation of new leinamycin analogues produced via the use of combinatorial biosynthesis is described.

Research was conducted to examine the targeted mutants of Cochliobolus carbonum lacking the two major extracellular polygalacturonases (exoPG). The purification of the exoPG activity of C carbonum and the cloning of its gene, PGX1, was also performed. Double pgn1/pgx1 mutant strain was developed by crossing. The continued growth of the pgn1/pgx1 mutant strain on pectin could be attributed to one or more of PG residual activities.

Presents a study to address the requirement for any pectin-degrading ability in pathogenesis by Cochliobolus carbonum. Methodology used to conduct study; Indication of findings; Discussion on results.

As a ubiquitous second messenger, cyclic dimeric GMP (c-di-GMP) has been studied in numerous bacteria. The oral spirochete Treponema denticola, a periodontal pathogen associated with human periodontitis, has a complex c-di-GMP signaling network. However, its function remains unexplored. In this report, a PilZ-like c-di-GMP binding protein (TDE0214) was studied to investigate the role of c-di-GMP in the spirochete. TDE0214 harbors a PilZ domain with two signature motifs: RXXXR and DXSXXG. Biochemical studies showed that TDE0214 binds c-di-GMP in a specific manner, with a dissociation constant (Kd) value of 1.73 μM, which is in the low range compared to those of other reported c-di-GMP binding proteins. To reveal the role of c-di-GMP in T. denticola, a TDE0214 deletion mutant (TdΔ214) was constructed and analyzed in detail. First, swim plate and single-cell tracking analyses showed that TdΔ214 had abnormal swimming behaviors: the mutant was less motile and reversed more frequently than the wild type. Second, we found that biofilm formation of TdΔ214 was substantially repressed (∼6.0-fold reduction). Finally, in vivo studies using a mouse skin abscess model revealed that the invasiveness and ability to induce skin abscesses and host humoral immune responses were significantly attenuated in TdΔ214, indicative of the impact that TDE0214 has on the virulence of T. denticola. Collectively, the results reported here indicate that TDE0214 plays important roles in motility, biofilm formation, and virulence of the spirochete. This report also paves a way to further unveil the roles of the c-di-GMP signaling network in the biology and pathogenicity of T. denticola.

There is growing interest in discovery of novel bioactive natural products from Burkholderia thailandensis. Here we report a significantly improved genome sequence and reannotation of Burkholderia thailandensis MSMB43, which will facilitate the discovery of new natural products through genome mining and studies of the metabolic versatility of this bacterium.