30. Altschul SF, Gish W, Miller W, Myers EW, Lipman DJ: Basic local alignment search tool. J Mol Biol 1990, 215:403–410.PubMedCrossRef 31. Jukes TH, Cantor CR: Evolution of Protein Molecules. New York: Academic; 1969. 32. Dorrestein PC, Yeh E, Garneau-Tsodikova S, Kelleher NL, Walsh CT: Dichlorination of a pyrrolyl-S-carrier protein by FADH 2 -dependent halogenase PltA during pyoluteorin biosynthesis. Proc

Natl Acad Sci U S A 2005, 102:13843–13848.PubMedCentralPubMedCrossRef 33. Hoppe I, Schöllkopf U: Synthesis and biological activities of the antibiotic B 371 and its analogs. Liebigs Ann Chem 1984, 1984:600–607.CrossRef 34. Drake EJ, Gulick AM: Three-dimensional structures of Pseudomonas aeruginosa PvcA and PvcB, two proteins involved in the synthesis of 2-isocyano-6,7-dihydroxycoumarin. J Mol Biol 2008, 384:193–205.PubMedCentralPubMedCrossRef mTOR inhibitor review Competing interests this website The authors declare that they have no competing interests. Authors’ contributions MCM and RV designed the overall project. MLM and MCM sequenced the genomes of WI HT-29-1 and HW IC-52-3. DS and RV sequenced the genomes of FA UTEX1903 and FS ATCC43239. MLM and DS jointly contributed to identification and functional assignment of the gene clusters. MLM and LG jointly contributed to protein expression of WelP1, WelH and SsuE. BMB contributed to the functional assignment, protein expression

and reconstitution of WelI1 and WelI3. DS contributed to chemical synthesis and characterization of cyanobacterial extracts.

MCM, LG and RV edited the final version of the manuscript drafted jointly by MLM, DS and BMB. PFKL All authors read and approved the final manuscript.”
“Background Mutualistic associations between invertebrate hosts and bacteria are widespread in nature [1] and have important implications for host ecology and evolution [2]. While the taxonomic and functional diversity of bacterial symbionts has been – and continues to be – studied extensively, particularly in insects, the fastidious nature of most symbiotic bacteria and their refractoriness to axenic cultivation [3] has in most cases hampered detailed investigations of the symbionts’ physiology and the molecular underpinnings of symbiosis establishment through targeted Tipifarnib genetic manipulation (but see [4–7]). Most insect-bacteria symbioses have a nutritional basis, with Proteobacteria, Firmicutes, and Bacteroidetes as especially common and widespread symbionts providing limiting nutrients to their hosts [8]. However, more and more defensive alliances for the host’s protection against parasitoids, predators, and/or pathogens are being discovered [9,10], and filamentous Actinobacteria are especially prevalent as protective symbionts, due to their ability to produce a range of bioactive secondary metabolites [11,12].