The first enzyme, RhlA, is responsible for the interception of two molecules of β-hydroxydecanoyl-ACP, an intermediate in the de novo fatty acid biosynthesis cycle, to produce

P005091 solubility dmso 3-hydroxyalkanoic acid dimers, known as 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) [16, 17]. The second reaction, implicating the membrane-bound RhlB rhamnosyltransferase, uses dTDP-L-rhamnose to add the first rhamnose moiety to an HAA molecule, thus forming a monorhamnolipid (L-rhamnosyl-3-hydroxyalkanoyl-3-hydroxyalkanoate). Finally, an additional rhamnosyltransferase, RhlC, couples a second rhamnose molecule to a monorhamnolipid by the means of another dTDP-L-rhamnose, producing the final dirhamnolipid (L-rhamnosyl-L-rhamnosyl-3-hydroxyalkanoyl-3-hydroxyalkanoate)

[18, 19]. Previously assigned to the see more Pseudomonas genus, Burkholderia spp. are attracting increasing interest because of their involvement in human infections. Burkholderia is best known for its pathogenic members like B. pseudomallei, the causative agent of melioidosis, as well as the opportunistic pathogens belonging to the B. cepacia complex [20, 21]. Two studies have reported evidence of the production of a single dirhamnolipid by B. pseudomallei as well as by another member of the same genus, B. plantarii [22, 23]. Here, we investigate the production of rhamnolipids by B. thailandensis, a non-infectious Burkholderia species closely related to B. pseudomallei [24], and by B. pseudomallei itself. In contrast to the mandated L-NAME HCl B. pseudomallei guidelines, an advantage to studying B. thailandensis is find more that it does not require biosafety level 3 conditions, and there is no restriction on the use of antibiotic-resistance markers for its genetic manipulation. In addition, numerous studies have shown to what extreme level these two Burkholderia species are closely related from a genetic

point of view and that B. thailandensis can serve as a surrogate for studying many different traits, including physiological characteristics as well as pathogenic factors in regards to B. pseudomallei [25, 26]. Results Presence of rhlABC homologs in B. thailandensis and B. pseudomallei Following a nucleotide and protein similarity search using algorithms blastn and blastp with standard parameters http://​blast.​ncbi.​nlm.​nih.​gov/​Blast.​cgi, respectively, in sequenced B. thailandensis and B. pseudomallei genome sequences, close orthologs of the P. aeruginosa rhamnolipid-biosynthesis genes rhlA, rhlB and rhlC were found in all associated strains as gene clusters. Interestingly, both species possess two 100% identical rhl gene clusters on their second chromosome (Figure 1). A search in the partially sequenced genome of B. pseudomallei 1026b (Genomes OnLine Database; http://​www.​genomesonline.