CHARACTERIZATION OF SECONDARY METABOLITE BIOSYNTHESIS PATHWAYS IN S. EUROCIDICUS.

BÁRBARA AYLÉN BERCOVICH (1), ROMINA CELADA (2), GUILLERMO LABADIE (2), DANIEL KURTH (3), HUGO GRAMAJO (1), EDUARDO J. RODRIGUEZ

Congreso; SAIB 2017; 2017

is a pentaene macrolide with antifungal activity. And Tertiomycin isan antibacterial compound from the spiramycin family with activityagainst Gram-positive bacteria, but the structure is still unknown.With the aim of study the biosynthetic pathwayof these metabolites,we have first validated the production of each of the using S. eurocidicusNRRL B-1676 strain. In liquid media culture it was found thateurocidin is produced in the exponential phase while both azomycinand tertiomycin are produced in the stationary phase of growth. Surprisingly,it was found that S. eurocidicus has a compound, presumably Streptomyces eurocidicus produces at least three secondary metabolites,azomycin, eurocidin and tertiomycin, which its biosynthesispathways are unknown. Azomycin is a broad-spectrum antibioticbelonging to the group of nitroheterocyclic compounds. Eurocidin, with a strong fluorescence that stains colonies on solidand liquid media. The identity of each compound was determined byTLC observed by UV at 254/302 nm and by p-anisaldehyde staining,or by high resolution LC-MS. In turn, the activities of each spotobserved were determined by inhibition against Bacillus subtilis orSaccharomyces cerevisiae. Then, we have sequenced the S. eurocidicusNRRL B-1676 genome by 100bp paired-end reads usingIlumina technology. Analysis of the genome sequence allowed identifyingputative gene cluster for each metabolite using bioinformatictools. To validate these gene clusters we are constructing knock-outstrains by homologous recombination or by UV mutagenesis. Thus,mutant strains for eurocidin gene cluster were obtained and it wasfound that they lost antifungal activity and are not fluorescent.