Bacterial intracellular nanoparticles exhibiting antioxidant properties and the significance of their formation in ROS detoxification

Abstract

Summary Biogenic magnetic nanoparticles (BMNPs) can be formed by numerous microorganisms. However, the significance of their formation and their possible functions have not been explored in detail. To explore a possible function of Fe3O4 NPs in Burkholderia sp. strain YN01, we investigated their catalytic abilities in the elimination of intracellular reactive oxygen species (ROS). Changes in ROS content under different conditions were assessed and showed that low oxygen and high iron concentrations in the growth medium promoted ROS production. However, the levels of ROS gradually decreased with BMNP formation, suggesting that these particles possess intrinsic superoxide dismutase (SOD)‐like activity and catalase (CAT)‐like activity, as proven in this study. To ensure that the observed ROS decrease was not due to antioxidase overexpression caused by the oxidative stress response, SOD and CAT were inhibited in vivo to analyse the ROS variation and BMNP yield under microoxic and high‐iron conditions respectively. The results demonstrated that the formation of these intracellular iron nanoparticles was required for the efficient scavenging of excess ROS, which was dependent on their antioxidase‐like properties. This result reveals a novel physiological function of biogenic intracellular Fe3O4 nanoparticles.

A Drug-free, Self-destruction Strategy to Combat Bacterial Infections by Using the Intrinsically formed Magnetic Nanoparticles in Bacterial Pathogens

“…In a recent study with magnetotactic bacteria ( Burkholderia sp. ), Pan et al had concluded that the MNPs in the bacteria help in the efficient scavenging of excess ROS, by the antioxidase-like activity of iron crystals [35] . The MNPs observed in the pathogenic bacteria might also follow a similar strategy to overcome ROS-induced toxicity.…”

Fe3O4 nanozyme coating enhances light‐driven biohydrogen production in self‐photosensitized Shewanella oneidensis‐CdS hybrid systems

“…activities and can effectively inhibit oxidative stress in the cellular environment. [26] Here, we selected an electro-active bacterium, S. oneidensis MR-1, as a model to demonstrate its unique biotic-abiotic interface behavior, owing to its ability to anaerobically produce hydrogen gas and biosynthesize CdS and Fe 3 O 4 nanoparticles. We investigated whether the simultaneous synthesis of highly light-collecting CdS nanoparticles and Fe 3 O 4 nanozymes on the cell surface could be used more efficiently for hydrogen production by exploiting bacterial bioreactions.…”

What are inorganic nanozymes? Artificial or inorganic enzymes

“…Inorganic iron oxide nanoparticles from different bacteria, namely Magnetospirillum magneticum strain AMB-1 190,191 (Fe 3 O 4 , after removing the magnetosome membrane), Burkholderia sp. YN01v 192,193 (Fe 3 O 4 ), Comamonas testosterone 194 (Fe 1.44 O 0.32 (OH) 3.86 ), and Acinetobacter strains 195 (Fe 0.96 O 0.88 (OH) 1.12 ), exhibited intrinsic POD-like, 190–195 SOD-like, 193 and CAT-like activities. 193 These bacteria belong to the Gram-negative group and are widespread everywhere on the Earth, including marine habitats.…”

“…YN01v 192,193 (Fe 3 O 4 ), Comamonas testosterone 194 (Fe 1.44 O 0.32 (OH) 3.86 ), and Acinetobacter strains 195 (Fe 0.96 O 0.88 (OH) 1.12 ), exhibited intrinsic POD-like, 190–195 SOD-like, 193 and CAT-like activities. 193 These bacteria belong to the Gram-negative group and are widespread everywhere on the Earth, including marine habitats. 196–199 In addition, magnetotactic bacteria can be traced back to the Archean era, and thus constitute one of the oldest organisms known to exist on the planet today.…”