A Comprehensive Assessment of the Genetic Determinants in Salmonella Typhimurium for Resistance to Hydrogen Peroxide Using Proteogenomics

Karash, Sardar; Liyanage, Rohana; Qassab, Abdullah; Lay, Jackson O.; Kwon, Young Min

doi:10.1038/s41598-017-17149-9

Cited by 32 publications

(32 citation statements)

References 75 publications

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“…S2A). However, Salmonella is significantly more resistant to H 2 O 2 than is C. rodentium, due to the presence of redundant catalases and alkyl hydroperoxide reductases [25][26][27] . Consistent with this, we failed to observe a growth phenotype when we subjected WT Salmonella and all possible combinations of sseK1/K2/K3 mutants to 12.0 mM H 2 O 2 , a concentration 5-times greater than that used for C. rodentium experiments (Fig.…”

Section: Resultsmentioning

confidence: 99%

An intra-bacterial activity for a T3SS effector

Qaidi

Scott

Hays

et al. 2020

Sci Rep

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Many Gram-negative bacterial pathogens interact with mammalian cells by using type iii secretion systems (T3SS) to inject virulence proteins into host cells. A subset of these injected protein 'effectors' are enzymes that inhibit the function of host proteins by catalyzing the addition of unusual posttranslational modifications. The E. coli and Citrobacter rodentium NleB effectors, as well as the Salmonella enterica SseK effectors are glycosyltransferases that modify host protein substrates with N-acetyl glucosamine (GlcNAc) on arginine residues. This post-translational modification disrupts the normal functioning of host immune response proteins. T3SS effectors are thought to be inactive within the bacterium and fold into their active conformations after they are injected, due to the activity of chaperones that keep the effectors in a structural state permissive for secretion. While performing mass spectrometry experiments to identify glycosylation substrates of nleB orthologs, we unexpectedly observed that the bacterial glutathione synthetase (GshB) is glycosylated by NleB on arginine residue R256. NleB-mediated glycosylation of GshB resulted in enhanced GshB activity, leading to an increase in glutathione production, and promoted C. rodentium survival in oxidative stress conditions. these data represent, to our knowledge, the first intra-bacterial activity for a T3SS effector and show that arginine-GlcnAcylation, once thought to be restricted to host cell compartments, also plays an important role in regulating bacterial physiology.

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Section: Resultsmentioning

confidence: 99%

An intra-bacterial activity for a T3SS effector

Qaidi

Scott

Hays

et al. 2020

Sci Rep

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“…The levels of transcription of nemAR, encoding the oxidative stress-responsive regulator NemR and the reactiveelectrophile neutralizing N-ethylmaleimide reductase NemA (36, 37) increased 2.8-and 7.4-fold, respectively, under these conditions. Other oxidative stress response genes were also expressed, including ybbL (2.5-fold increase) and a hydrogen peroxideinducible gene of unknown function, ybjM (2.9-fold increase) (38,39).…”

Section: Resultsmentioning

confidence: 99%

Pulmonary Surfactant Promotes Virulence Gene Expression and Biofilm Formation in Klebsiella pneumoniae

et al. 2018

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The interactions between and the host environment at the site of infection are largely unknown. Pulmonary surfactant serves as an initial point of contact for inhaled bacteria entering the lung and is thought to contain molecular cues that aid colonization and pathogenesis. To gain insight into this ecological transition, we characterized the transcriptional response of MGH 78578 to purified pulmonary surfactant. This work revealed changes within the transcriptome that likely contribute to host colonization, adaptation, and virulence Notable transcripts expressed under these conditions include genes involved in capsule synthesis, lipopolysaccharide modification, antibiotic resistance, biofilm formation, and metabolism. In addition, we tested the contributions of other surfactant-induced transcripts to survival using engineered isogenic KPPR1 deletion strains in a murine model of acute pneumonia. In these infection studies, we identified the MdtJI polyamine efflux pump and the ProU glycine betaine ABC transporter to be significant mediators of survival within the lung and confirmed previous evidence for the importance of leucine synthesis to bacterial survival during infection. Finally, we determined that pulmonary surfactant promoted type 3 fimbria-mediated biofilm formation in and identified two surfactant constituents, phosphatidylcholine and cholesterol, that drive this response. This study provides novel insight into the interactions occurring between and the host at an important infection site and demonstrates the utility of purified lung surfactant preparations for dissecting host-lung pathogen interactions.

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“…We then asked if our discovery could be considered as a general extension of the concept to iron-restricted conditions. To answer this question, we closely examined our Tn-seq data that were generated for other stress conditions such as H 2 O 2 [ 18 ] and H 2 O 2 coupled with Dip (unpublished). However, we could not find any similar patterns that a significant portion of the essential genes in LB medium became nonessential under stress conditions.…”

Section: Resultsmentioning

confidence: 99%

“…All procedures involving this pathogen (Biosafety level 2) were conducted according to the protocol approved by Institutional Biosafety Committee (IBC) at the University of Arkansas. Transposon mutant libraries were prepared as previously described [ 18 ]. Briefly, S. Typhimurium ATCC 14028 NA R (the recipient strain) was subjected to transposon mutagenesis by biparental mating using Escherichia coli SM10 λ pir carrying a pBAM1 transposon-delivery plasmid vector [ 44 ] as the donor strain.…”

Section: Methodsmentioning

confidence: 99%

Iron-dependent essential genes in Salmonella Typhimurium

Karash

Kwon

2018

BMC Genomics

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BackgroundThe molecular mechanisms underlying bacterial cell death due to stresses or bactericidal antibiotics are complex and remain puzzling. Due to the current crisis of antibiotic resistance, development of effective antibiotics is urgently required. Previously, it has been shown that iron is required for effective killing of bacterial cells by numerous bactericidal antibiotics.ResultsWe investigated the death or growth inhibition of S. Typhimurium under iron-restricted conditions, following disruption of essential genes, by transposon mutagenesis using transposon sequencing (Tn-seq). Our high-resolution Tn-seq analysis revealed that transposon mutants of S. Typhimurium with insertions in essential genes escaped immediate killing or growth inhibition under iron-restricted conditions for approximately one-third of all previously known essential genes. Based on this result, we classified all essential genes into two categories, iron-dependent essential genes, for which the insertion mutants can grow slowly if iron is restricted, and iron-independent essential genes, for which the mutants become nonviable regardless of iron concentration. The iron-dependency of the iron-dependent essential genes was further validated by the fact that the relative abundance of these essential gene mutants increased further with more severe iron restrictions. Our unexpected observation can be explained well by the common killing mechanisms of bactericidal antibiotics via production of reactive oxygen species (ROS). In this model, iron restriction would inhibit production of ROS, leading to reduced killing activity following blocking of essential gene functions. Interestingly, the targets of most antibiotics currently in use clinically are iron-dependent essential genes.ConclusionsOur result suggests that targeting iron-independent essential genes may be a better strategy for future antibiotic development, because blocking their essential gene functions would lead to immediate cell death regardless of the iron concentration. This work expands our knowledge on the role of iron to a broad range of essential functions and pathways, providing novel insights for development of more effective antibiotics.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-4986-1) contains supplementary material, which is available to authorized users.

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A Comprehensive Assessment of the Genetic Determinants in Salmonella Typhimurium for Resistance to Hydrogen Peroxide Using Proteogenomics

Cited by 32 publications

References 75 publications

An intra-bacterial activity for a T3SS effector

An intra-bacterial activity for a T3SS effector

Pulmonary Surfactant Promotes Virulence Gene Expression and Biofilm Formation in Klebsiella pneumoniae

Iron-dependent essential genes in Salmonella Typhimurium

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