Production of antimicrobial metabolites against pathogenic bacteria and yeasts by Fusarium oxysporum in submerged culture processes.

The antimicrobial activity of the metabolites produced by Fusarium oxysporum PR-33 in submerged culture was evaluated against Gram-positive and Gram-negative bacteria and yeasts. Metabolites were determined by HPLC-DAD-MS/MS. An extract was obtained following the removal of mycelium by centrifugation and lyophilisation of the supernatant. The compounds in this extract demonstrated broad-spectrum antimicrobial action, with rates of inhibition between 60 and 80%, depending on the species and extract tested. The major compounds of the extracts were identified as fusarinolic acid and its isomer [56.9% flask extract (FE)] and 59.2% bioreactor extract (BE), dehydrofusaric acid (35.7% FE and 31.6% BE), and fusaric acid (6.5% FE and 1.1% BE). Fusaric acid has been shown to be responsible for antimicrobial activity. The cytotoxicity of the extracts was evaluated in culture of HEK-293 and SH-SY5Y animal cells and toxicity of these extracts was verified even in the lowest tested concentrations. Therefore, our results indicate that the compounds identified exhibit potential as antimicrobial agents.

Gene Regulatory Networks of Penicillium echinulatum 2HH and Penicillium oxalicum 114-2 Inferred by a Computational Biology Approach.

Penicillium echinulatum 2HH and Penicillium oxalicum 114-2 are well-known cellulase fungal producers. However, few studies addressing global mechanisms for gene regulation of these two important organisms are available so far. A recent finding that the 2HH wild-type is closely related to P. oxalicum leads to a combined study of these two species. Firstly, we provide a global gene regulatory network for P. echinulatum 2HH and P. oxalicum 114-2, based on TF-TG orthology relationships, considering three related species with well-known regulatory interactions combined with TFBSs prediction. The network was then analyzed in terms of topology, identifying TFs as hubs, and modules. Based on this approach, we explore numerous identified modules, such as the expression of cellulolytic and xylanolytic systems, where XlnR plays a key role in positive regulation of the xylanolytic system. It also regulates positively the cellulolytic system by acting indirectly through the cellodextrin induction system. This remarkable finding suggests that the XlnR-dependent cellulolytic and xylanolytic regulatory systems are probably conserved in both P. echinulatum and P. oxalicum. Finally, we explore the functional congruency on the genes clustered in terms of communities, where the genes related to cellular nitrogen, compound metabolic process and macromolecule metabolic process were the most abundant. Therefore, our approach allows us to confer a degree of accuracy regarding the existence of each inferred interaction.