The antioxidant drug N-acetylcysteine abolishes SOS-mediated mutagenesis produced by fluoroquinolones in bacteria

Abstract

Certain antibiotics, particularly fluoroquinolones, induce the mutagenic SOS response and increase the levels of intracellular reactive oxygen species (ROS), which have been correlated with antibiotic lethality. Both SOS and ROS increase mutagenesis in treated bacteria, likely resulting in the appearance of resistant mutants during antibiotic treatments. However, the relative contribution of ROS and SOS on this antibiotic-mediated mutagenesis is currently unknown. We used the antioxidant molecule N-acetylcysteine (NAC) to study the contribution of ROS on the SOS response and mutagenesis mediated by the fluoroquinolone antibiotic ciprofloxacin (CIP). We show that NAC is able to reduce intracellular ROS levels, mitigating as well the SOS response caused by treatment with subinhibitory concentrations of CIP. This effect leads to the reduction of antibiotic-induced mutagenesis to levels comparable to a translesion DNA-polymerases (TLS) deficient strain, suggesting that ROS play a major role in SOS-induced mutagenesis. Collectively, our results shed light on the mechanisms underlying antibiotic-induced mutagenesis and pave the way for the use of NAC as a safe adjuvant in antibiotic therapy to inhibit antibiotic-induced mutagenesis, hence augmenting our capacity to fight against threatening bacterial infections.

Can debarking affects sex ratio, population structure and spatial segregation?: insights of unsustainable harvesting in a Mesoamerican tropical tree

“…Despite our evidence of the dominance of a certain sex in each condition (harvested vs. nonharvested; Figure 2), we did not observe spatial segregation of the sexes. This finding contrasts with the theory (Bierzychudek and Eckhart 1988;Barret and Hough 2013) since debarking induces physiological stress at the individual level (Baldauf and dos Santos 2014;Romero 2014) and environmental stress when trees are cut down and forest gaps appear (Beltrán-Rodríguez 2018). Therefore, we would have expected the dominance of androecious plants in the richest spaces in terms of resources (Cox 1981;Munné-Bosch 2015).…”

“…Spatial organization distances between seedlings (black squares) and saplings (white triangles) by plot (b, d, f, h). tivity and hydraulic safety in their secondary xylem, which endows them with a greater radial growth rate than does androecious plants (Beltrán-Rodríguez 2018;Beltrán-Rodríguez et al 2022b). Even though greater growth leads to less efficient water use be-cause of high evaporative demand through stomatic conduct (Dawson and Geber 1999;Pittermann 2010), it also allows trees to reach the superior canopy faster and increase their competitive capacity, ensuring reproduction (Poorter et al 2009;Wright et al 2010;.…”

“…Can debarking affect the sex ratio, population structure and spatial segregation? Insights of unsustainable harvesting in an Mesoamerican tropical tree Ethnobiol Conserv 13:08 Rodríguez 2018). These allometric conditions could affect the microclimate of the understory and, consequently, the establishment and growth of seedlings and saplings.…”

Growth Rate and Antibiotic Sensitivity Effect of Some Natural and Petroleum Based Materials on Staphylococcus aureus

“…Since antibiotic discovery, bacteria was able to develop resistance after few years from its first use. This development, together with the existing paucity in the antibiotic pipeline, renders every antibiotic into a nonrenewable resource that should be carefully rationed [1,2]. Recently, the consumption of power drinks, cigarette, soft drinks and even hot drinks such as coffee and tea become necessary in almost everybody's life [3].…”