AUTHOR=Navarro Miguel Octavio Pérez , Dilarri Guilherme , Simionato Ane Stefano , Grzegorczyk Kathlen , Dealis Mickely Liuti , Cano Barbara Gionco , Barazetti André Riedi , Afonso Leandro , Chryssafidis Andreas Lazaros , Ferreira Henrique , Andrade Galdino TITLE=Determining the Targets of Fluopsin C Action on Gram-Negative and Gram-Positive Bacteria JOURNAL=Frontiers in Microbiology VOLUME=11 YEAR=2020 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.01076 DOI=10.3389/fmicb.2020.01076 ISSN=1664-302X ABSTRACT=

The antibiotic activity of metalloantibiotic compounds has been evaluated since the 90s, and many different modes of action were characterized. In the last decade, the effects of secondary metabolites produced by Pseudomonas aeruginosa LV strain, including a cupric compound identified as Fluopsin C, were tested against many pathogenic bacteria strains, proving their high antibiotic activity. In the present study, the bactericidal mechanisms of action of Fluopsin C and the semi-purified fraction F4A were elucidated. The results found in electron microscopy [scanning electron microscopy (SEM) and transmission electronic microscopy (TEM)] demonstrated that both Fluopsin C and F4A are affecting the cytoplasmatic membrane of Gram-positive and Gram-negative bacteria. These results were confirmed by fluorescence microscopy, where these bacteria presented permeabilization of their cytoplasmatic membranes after contact with the semi-purified fraction and pure compound. Using electronic and fluorescence microscopy, along with bacterial mutant strains with marked divisional septum, the membrane was defined as the primary target of Fluopsin C in the tested bacteria.