Project description:In submerged cultivation of filamentous microbes, including actinomycetes, complex morphology is one of the critical process features for secondary metabolites production. Ansamitocin P-3 (AP-3), an antitumor agent, is a secondary metabolite produced by Actinosynnema pretiosum ATCC 31280. An excessive mycelial fragmentation of A. pretiosum ATCC 31280 was observed during the early stage of fermentation. In order to identify genes involved in the early mycelial fragmentation, the total RNAs of mycelia collected at 15, 18, and 24 h were extracted and subjected to transcriptome sequencing using RNA-seq technology.Through comparative transcriptomic analysis, a subtilisin-like serine peptidase encoded gene APASM_4178 was identified to be responsible for the mycelial fragmentation. Mutant WYT-5 with the APASM_4178 deletion showed increased biomass and improved AP-3 yield by 43.65%.
Project description:In search of AP-3 resistant genes, ATCC 31280△ansaA (inactivation of ansamitocin pksA, in avoiding of the interruption of endogenous generated AP-3) were cultured under the addition of 0, 50, 100 and 200 mg/L exogenous AP-3 for 24 h and collected, for strains under 200 mg/L AP-3, samples after 48 h and 72 h were also collected, and the RNA samples were collected and sent for sequencing.
Project description:To explore gene expression and search for the ansamitocin resistant genes during fermentation, total RNA of the ansmitocin high producer NXJ-24 and the wildtype strain ATCC31280 were extracted and sequenced. The gene expression values from day 1 to day 5 of NXJ-24 and day 5 of ATCC31280 were compared. 6 genes were considered most likely to be the ansamitocin transporter genes.