Deciphering the Role of Multiple Thioredoxin Fold Proteins of Leptospirillum sp. in Oxidative Stress Tolerance

Abstract

Thioredoxin fold proteins (TFPs) form a family of diverse proteins involved in thiol/disulfide exchange in cells from all domains of life. Leptospirillum spp. are bioleaching bacteria naturally exposed to extreme conditions like acidic pH and high concentrations of metals that can contribute to the generation of reactive oxygen species (ROS) and consequently the induction of thiol oxidative damage. Bioinformatic studies have predicted 13 genes that encode for TFP proteins in Leptospirillum spp. We analyzed the participation of individual tfp genes from Leptospirillum sp. CF-1 in the response to oxidative conditions. Genomic context analysis predicted the involvement of these genes in the general thiol-reducing system, cofactor biosynthesis, carbon fixation, cytochrome c biogenesis, signal transduction, and pilus and fimbria assembly. All tfp genes identified were transcriptionally active, although they responded differentially to ferric sulfate and diamide stress. Some of these genes confer oxidative protection to a thioredoxin-deficient Escherichia coli strain by restoring the wild-type phenotype under oxidative stress conditions. These findings contribute to our understanding of the diversity and complexity of thiol/disulfide systems, and of adaptations that emerge in acidophilic microorganisms that allow them to thrive in highly oxidative environments. These findings also give new insights into the physiology of these microorganisms during industrial bioleaching operations.

miRNA-141 Induced Pyroptosis in Intervertebral Disk Degeneration by Targeting ROS Generation and Activating TXNIP/NLRP3 Signaling in Nucleus Pulpous Cells

“…We further investigated the mechanism by which miR-141 regulates pyroptosis. The acidic microenvironment in degenerative IVD induces excessive ROS generation ( Gonzalez et al, 2020 ). Indeed, the ROS levels were higher in degenerated NPs compared to normal NPs from human and rat.…”

A novel gene from the acidophilic bacterium Leptospirillum sp. CF-1 and its role in oxidative stress and chromate tolerance

“…Members of the genus Leptospirillum grow under these environmental conditions in the absence of canonical antioxidant systems, namely superoxide dismutase (SOD), catalase (CAT), and glutathione [ 1 , 3 ]. However, alternative molecular mechanisms to maintain redox homeostasis have been described in Leptospirillum spp., including the thiol/disulfide system [ 6 ], Dyp-type peroxidases (DyP) [ 7 ], cytochrome c peroxidases (CcP) [ 8 ] and even the use of cobalamin to protect against oxidative conditions [ 3 ]. In the present study, we generated experimental evidence that directly or indirectly links the protein encoded by the hypothetic gene ABH19_09590 of Leptospirillum sp.…”

“…CF-1 is an aerobic acidophilic iron-oxidizing bacterium with the capacity to survive in extremely acidic natural or man-made environments, and in high concentrations of dissolved metal(loids) such as Cu, Zn, Al, Cd, Cu, Ni, Cr and As [ 3 , 5 ]. We have investigated the molecular mechanisms that mediate the antioxidant response in Leptospirillum spp., and have established that members of this genus have a highly abundant and efficient thiol/disulfide system [ 6 ]. Leptospirillum spp.…”

Identification of differentially expressed transcripts for trunk formation in sago palm using annealing control primer GeneFishing technique

“…The other redox-related protein, TRX-m 3 , regulates redox homeostasis, and this role was also found to relate to the cellular transport regulating functions. TRX-m 3 reduces plastid glucose-6-phosphate dehydrogenase (G6PDH), one of the enzymes in the oxidative pentose phosphate pathway [28]. The reaction then allows for NADPH regeneration, which is essential in preventing oxidative stress.…”