Characterization of the iron-regulated desA promoter of Streptomyces pilosus as a system for controlled gene expression in actinomycetes

Abstract

Background: The bioavailability of iron is quite low since it is usually present as insoluble complexes. To solve the bioavailability problem microorganisms have developed highly efficient iron-scavenging systems based on the synthesis of siderophores that have high iron affinity. The systems of iron assimilation in microorganisms are strictly regulated to control the intracellular iron levels since at high concentrations iron is toxic for cells. Streptomyces pilosus synthesizes the siderofore desferrioxamine B. The first step in desferrioxamine biosynthesis is decarboxylation of L-lysine to form cadaverine, a desferrioxamine B precursor. This reaction is catalyzed by the lysine decarboxylase, an enzyme encoded by the desA gene that is repressed by iron.

Identification of iron-regulated genes of Bifidobacterium breve UCC2003 as a basis for controlled gene expression

“…Similarly for the actinomycetes the iron-regulated desA promoter serves as an inducible system for expression of genes in Streptomyces pilosus following iron removal with dipyridyl. 37 Apart from B. longum JCM7052, growth of all other Bifidobacterium strains tested showed an inverse concentration-dependent correlation between the added amount of chelator and final optical density reached following 15 h of growth. The lack of growth inhibition of B. longum JCM7052 when exposed to dipyridyl may indicate, similar to the findings reported for B. longum DJO10A, 23 that this strain produces a siderophore that endows it with a very efficient iron scavenging ability.…”

“…The actual induction level measured using this dipyridyl-inducible promoter is likely to be higher than the observed 5-fold, although it is comparable to the (2-7 fold) increase observed with the desAamylase dipyridyl-inducible system developed for Streptomyces pilosus. 37 However, the control plasmid produces a significant level of background GUS activity, which is probably due to transcription originating from elsewhere on the pNZ-derived plasmid. This inducible system could therefore be improved by the inclusion of a transcriptional "silencer" just upstream of the bfeU-derived promoter.…”

Actinobacteria as Plant Growth-Promoting Rhizobacteria

“…Authors like Diaz [30] proved that strains of actinobacteria such as Streptomyces MCR3 and Thermobifida showed a great synthesis of siderophores of the hydroxamate-type using glucose as the only source of carbon, in contrast to what occurred when sodium succinate was utilized to the same purposed. Concerning Streptomyces sp., the production of hydroxamate-Desferrioxamine [37,38] B by this microorganism is well documented. On the other hand, Thermobifida has been recently reported as the producer of a siderophore known as fuscachelin A [39].…”

“…Streptomyces genus [47][48][49][50][51][52][53], Frankia sp. [47,51,54], Nocardia sp. [47,54], Kitasatospora sp.…”

Identification and molecular characterization of a metagenome-derived L-lysine decarboxylase gene from subtropical soil microorganisms

“…1,5-Pentanediamine produces nylon-5.10, which is lighter and has lower water absorption and better dimensional stability than nylon-6 [ 4 , 5 ]. In addition, 1,5-pentanediamine can be used to prepare desferrioxamine B for the treatment of iron overload and pathological iron deposition in humans [ 6 ]. 1,5-Pentanediamine is a cell wall component that maintains normal bacterial growth in some Gram-negative bacteria, such as Selenomonas ruminantium and Anaerovibrio lipolytica [ 7 – 9 ].…”