Transcriptome landscape unveils putative defense response in Chryseobacterium sp. strain PMSZPI against uranium...

Area of Science:

• Environmental microbiology
• Bacterial stress response
• Bioremediation of heavy metals

Background:

• Naturally occurring bacteria possess mechanisms to survive environmental stressors.
• Chryseobacterium sp. strain PMSZPI, isolated from uranium ore, exhibits high tolerance to heavy metals, including uranium (U).

Purpose of the Study:

• To investigate the physiological and transcriptome-wide defense responses of Chryseobacterium sp. strain PMSZPI to uranium exposure.
• To understand the molecular mechanisms underlying uranium resistance in this bacterium.

Main Methods:

• Exposure of PMSZPI to uranium (U) at 300 µM.
• Physiological analysis including reactive oxygen species (ROS) detection, protein carbonylation, and membrane permeability assessment.
• Transcriptome analysis (RNA sequencing) at 0.5 and 24 hours post-exposure.

Main Results:

• Uranium exposure induced oxidative stress (ROS accumulation), protein damage, and increased membrane permeability.
• Significant upregulation of genes involved in oxidative stress protection (superoxide dismutase, catalase, thiol peroxidase, ferritin) and heavy metal efflux (TonB-dependent receptors, RND transporters).
• Induction of DNA repair pathways (non-homologous end joining) and downregulation of metabolic pathways (ATP synthesis, translation, gluconeogenesis).

Conclusions:

• Chryseobacterium sp. strain PMSZPI employs a complex, temporally regulated response to tolerate uranium toxicity.
• Key mechanisms include robust oxidative stress management, active efflux of uranium, and DNA repair.
• Metabolic reprogramming supports survival under high uranium stress, offering insights for bioremediation strategies.