Comparative Analysis of the Global Transcriptomic Response to Oxidative Stress of Bacillus anthracis htrA-Disrupted and Parental Wild Type Strains

We previously demonstrated that the HtrA (High Temperature Requirement A) protease/chaperone active in the quality control of protein synthesis, represents an important virulence determinant of Bacillus anthracis. Virulence attenuation of htrA-disrupted Bacillus anthracis strains was attributed to susceptibility of ΔhtrA strains to stress insults, as evidenced by affected growth under various stress conditions. Here, we report a comparative RNA-seq transcriptomic study generating a database of differentially expressed genes in the B. anthracis htrA-disrupted and wild type parental strains under oxidative stress. The study demonstrates that, apart from protease and chaperone activities, HtrA exerts a regulatory role influencing expression of more than 1000 genes under stress. Functional analysis of groups or individual genes exhibiting strain-specific modulation, evidenced (i) massive downregulation in the ΔhtrA and upregulation in the WT strains of various transcriptional regulators, (ii) downregulation of translation processes in the WT strain, and (iii) downregulation of metal ion binding functions and upregulation of sporulation-associated functions in the ΔhtrA strain. These modulated functions are extensively discussed. Fifteen genes uniquely upregulated in the wild type strain were further interrogated for their modulation in response to other stress regimens. Overexpression of one of these genes, encoding for MazG (a nucleoside triphosphate pyrophosphohydrolase involved in various stress responses in other bacteria), in the ΔhtrA strain resulted in partial alleviation of the H2O2-sensitive phenotype.

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Environmental Conditions Modulate the Transcriptomic Response of Both Caulobacter crescentus Morphotypes to Cu Stress

Microorganisms ◽

10.3390/microorganisms9061116 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1116

Author(s):

Laurens Maertens ◽

Pauline Cherry ◽

Françoise Tilquin ◽

Rob Van Houdt ◽

Jean-Yves Matroule

Keyword(s):

Oxidative Stress ◽

Stress Response ◽

Stress Responses ◽

Caulobacter Crescentus ◽

Oxidative Stress Response ◽

Transport Systems ◽

Transcriptomic Response ◽

Swarmer Cell ◽

Cu Stress ◽

Cellular Environment

Bacteria encounter elevated copper (Cu) concentrations in multiple environments, varying from mining wastes to antimicrobial applications of copper. As the role of the environment in the bacterial response to Cu ion exposure remains elusive, we used a tagRNA-seq approach to elucidate the disparate responses of two morphotypes of Caulobacter crescentus NA1000 to moderate Cu stress in a complex rich (PYE) medium and a defined poor (M2G) medium. The transcriptome was more responsive in M2G, where we observed an extensive oxidative stress response and reconfiguration of the proteome, as well as the induction of metal resistance clusters. In PYE, little evidence was found for an oxidative stress response, but several transport systems were differentially expressed, and an increased need for histidine was apparent. These results show that the Cu stress response is strongly dependent on the cellular environment. In addition, induction of the extracytoplasmic function sigma factor SigF and its regulon was shared by the Cu stress responses in both media, and its central role was confirmed by the phenotypic screening of a sigF::Tn5 mutant. In both media, stalked cells were more responsive to Cu stress than swarmer cells, and a stronger basal expression of several cell protection systems was noted, indicating that the swarmer cell is inherently more Cu resistant. Our approach also allowed for detecting several new transcription start sites, putatively indicating small regulatory RNAs, and additional levels of Cu-responsive regulation.

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Escherichia coli MutM Suppresses Illegitimate Recombination Induced by Oxidative Stress

Genetics ◽

10.1093/genetics/151.2.439 ◽

1999 ◽

Vol 151 (2) ◽

pp. 439-446 ◽

Cited By ~ 2

Author(s):

Masaaki Onda ◽

Katsuhiro Hanada ◽

Hirokazu Kawachi ◽

Hideo Ikeda

Keyword(s):

Oxidative Stress ◽

Escherichia Coli ◽

Hydrogen Peroxide ◽

Dna Damage ◽

Double Strand Breaks ◽

Illegitimate Recombination ◽

Recombination Analysis ◽

Wild Type ◽

Strand Breaks ◽

In The Wild

Abstract DNA damage by oxidative stress is one of the causes of mutagenesis. However, whether or not DNA damage induces illegitimate recombination has not been determined. To study the effect of oxidative stress on illegitimate recombination, we examined the frequency of λbio transducing phage in the presence of hydrogen peroxide and found that this reagent enhances illegitimate recombination. To clarify the types of illegitimate recombination, we examined the effect of mutations in mutM and related genes on the process. The frequency of λbio transducing phage was 5- to 12-fold higher in the mutM mutant than in the wild type, while the frequency in the mutY and mutT mutants was comparable to that of the wild type. Because 7,8-dihydro-8-oxoguanine (8-oxoG) and formamido pyrimidine (Fapy) lesions can be removed from DNA by MutM protein, these lesions are thought to induce illegitimate recombination. Analysis of recombination junctions showed that the recombination at Hotspot I accounts for 22 or 4% of total λbio transducing phages in the wild type or in the mutM mutant, respectively. The preferential increase of recombination at nonhotspot sites with hydrogen peroxide in the mutM mutant was discussed on the basis of a new model, in which 8-oxoG and/or Fapy residues may introduce double-strand breaks into DNA.

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Increased sensitivity to oxidative injury in chinese hamster ovary cells stably transfected with rat liver S-adenosylmethionine synthetase cDNA

Biochemical Journal ◽

10.1042/bj3190767 ◽

1996 ◽

Vol 319 (3) ◽

pp. 767-773 ◽

Cited By ~ 28

Author(s):

Estrella SÁNCHEZ-GÓNGORA ◽

John G. PASTORINO ◽

Luis ALVAREZ ◽

María A. PAJARES ◽

Concepción GARCÍA ◽

...

Keyword(s):

Oxidative Stress ◽

Rat Liver ◽

Chinese Hamster Ovary ◽

Chinese Hamster Ovary Cells ◽

Chinese Hamster ◽

Wild Type ◽

Ovary Cells ◽

Transfected Cells ◽

In The Wild ◽

Adenosylmethionine Synthetase

Chinese hamster ovary cells were stably transfected with rat liver S-adenosylmethionine synthetase cDNA. As a result, S-adenosylmethionine synthetase activity increased 2.3-fold, an effect that was accompanied by increased S-adenosylmethionine, a depletion of ATP and NAD levels, elevation of the S-adenosylmethionine/S-adenosylhomocysteine ratio (the methylation ratio), increased DNA methylation and polyamine levels (spermidine and spermine), and normal GSH levels. By contrast, the transfected cells showed normal growth curves and morphology. Exposure to an oxidative stress by the addition of H2O2 resulted in a greater consumption of ATP and NAD in the transfected cells than in the wild-type cells. In turn, cell killing by H2O2 was greater in the transfected cells than in the wild-type cells. This killing of Chinese hamster ovary cells by H2O2 involved the activation of poly(ADP-ribose) polymerase with the resultant loss of NAD and ATP. 3-Aminobenzamide, an inhibitor of poly(ADP-ribose) polymerase, but not the antioxidant N,N´-diphenylphenylenediamine, prevented the killing of Chinese hamster ovary cells by H2O2 and maintained the contents of NAD and ATP. The results of this study indicate that a moderate activation of the synthesis of S-adenosylmethionine leads to ATP and NAD depletion and to a greater sensitivity to cell killing by oxidative stress.

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The SloR/Dlg Metalloregulator Modulates Streptococcus mutans Virulence Gene Expression

Journal of Bacteriology ◽

10.1128/jb.00155-06 ◽

2006 ◽

Vol 188 (14) ◽

pp. 5033-5044 ◽

Cited By ~ 50

Author(s):

Elizabeth Rolerson ◽

Adam Swick ◽

Lindsay Newlon ◽

Cameron Palmer ◽

Yong Pan ◽

...

Keyword(s):

Oxidative Stress ◽

Gene Expression ◽

Streptococcus Mutans ◽

Metal Ion ◽

Ion Homeostasis ◽

Virulence Gene ◽

Wild Type ◽

Genetic Competence ◽

Virulence Gene Expression ◽

Metal Ion Homeostasis

ABSTRACT Metal ion availability in the human oral cavity plays a putative role in Streptococcus mutans virulence gene expression and in appropriate formation of the plaque biofilm. In this report, we present evidence that supports such a role for the DtxR-like SloR metalloregulator (called Dlg in our previous publications) in this oral pathogen. Specifically, the results of gel mobility shift assays revealed the sloABC, sloR, comDE, ropA, sod, and spaP promoters as targets of SloR binding. We confirmed differential expression of these genes in a GMS584 SloR-deficient mutant versus the UA159 wild-type progenitor by real-time semiquantitative reverse transcriptase PCR experiments. The results of additional expression studies support a role for SloR in S. mutans control of glucosyltransferases, glucan binding proteins, and genes relevant to antibiotic resistance. Phenotypic analysis of GMS584 revealed that it forms aberrant biofilms on an abiotic surface, is compromised for genetic competence, and demonstrates heightened incorporation of iron and manganese as well as resistance to oxidative stress compared to the wild type. Taken together, these findings support a role for SloR in S. mutans adherence, biofilm formation, genetic competence, metal ion homeostasis, oxidative stress tolerance, and antibiotic gene regulation, all of which contribute to S. mutans-induced disease.

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Metal ion-binding properties of wild-type and mutant D37K of ciliate Euplotes octocarinatus centrin

Chinese Science Bulletin ◽

10.1007/s11434-010-3279-0 ◽

2010 ◽

Vol 55 (27-28) ◽

pp. 3118-3122 ◽

Cited By ~ 6

Author(s):

Wen Liu ◽

Lian Duan ◽

YaQin Zhao ◽

AiHua Liang ◽

BinSheng Yang

Keyword(s):

Metal Ion ◽

Ion Binding ◽

Wild Type ◽

Metal Ion Binding ◽

Binding Properties ◽

Euplotes Octocarinatus

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The Transcriptional Response to a Peroxisome Proliferator-activated Receptor α Agonist Includes Increased Expression of Proteome Maintenance Genes

Journal of Biological Chemistry ◽

10.1074/jbc.m409347200 ◽

2004 ◽

Vol 279 (50) ◽

pp. 52390-52398 ◽

Cited By ~ 64

Author(s):

Steven P. Anderson ◽

Paul Howroyd ◽

Jie Liu ◽

Xun Qian ◽

Rainer Bahnemann ◽

...

Keyword(s):

Oxidative Stress ◽

Stress Responses ◽

Transcriptional Response ◽

Lipid Homeostasis ◽

Peroxisome Proliferator ◽

Wild Type ◽

Peroxisome Proliferator Activated Receptor ◽

Proteasomal Genes ◽

Oxidative Stress Responses

The nuclear receptor peroxisome proliferator-activated receptor α (PPARα), in addition to regulating lipid homeostasis, controls the level of tissue damage after chemical or physical stress. To determine the role of PPARα in oxidative stress responses, we examined damage after exposure to chemicals that increase oxidative stress in wild-type or PPARα-null mice. Primary hepatocytes from wild-type but not PPARα-null mice pretreated with the PPAR pan-agonist WY-14,643 (WY) were protected from damage to cadmium and paraquat. The livers from intact wild-type but not PPARα-null mice were more resistant to damage after carbon tetrachloride treatment. To determine the molecular basis of the protection by PPARα, we identified by transcript profiling genes whose expression was altered by a 7-day exposure to WY in wild-type and PPARα-null mice. Of the 815 genes regulated by WY in wild-type mice (p≤ 0.001; ≥1.5-fold or ≤-1.5-fold), only two genes were regulated similarly by WY in PPARα-null mice. WY increased expression of stress modifier genes that maintain the health of the proteome, including those that prevent protein aggregation (heat stress-inducible chaperones) and eliminate damaged proteins (proteasome components). Although the induction of proteasomal genes significantly overlapped with those regulated by 1,2-dithiole-3-thione, an activator of oxidant-inducible Nrf2, WY increased expression of proteasomal genes independently of Nrf2. Thus, PPARα controls the vast majority of gene expression changes after exposure to WY in the mouse liver and protects the liver from oxidant-induced damage, possibly through regulation of a distinct set of proteome maintenance genes.

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Manganese Homeostasis in Group A Streptococcus Is Critical for Resistance to Oxidative Stress and Virulence

mBio ◽

10.1128/mbio.00278-15 ◽

2015 ◽

Vol 6 (2) ◽

Cited By ~ 34

Author(s):

Andrew G. Turner ◽

Cheryl-lynn Y. Ong ◽

Christine M. Gillen ◽

Mark R. Davies ◽

Nicholas P. West ◽

...

Keyword(s):

Oxidative Stress ◽

Hydrogen Peroxide ◽

Transition Metal ◽

Metal Ion ◽

Double Mutant ◽

Efflux Pump ◽

Group A Streptococcus ◽

Wild Type ◽

Group A

ABSTRACT Streptococcus pyogenes (group A Streptococcus [GAS]) is an obligate human pathogen responsible for a spectrum of human disease states. Metallobiology of human pathogens is revealing the fundamental role of metals in both nutritional immunity leading to pathogen starvation and metal poisoning of pathogens by innate immune cells. Spy0980 (MntE) is a paralog of the GAS zinc efflux pump CzcD. Through use of an isogenic mntE deletion mutant in the GAS serotype M1T1 strain 5448, we have elucidated that MntE is a manganese-specific efflux pump required for GAS virulence. The 5448ΔmntE mutant had significantly lower survival following infection of human neutrophils than did the 5448 wild type and the complemented mutant (5448ΔmntE::mntE). Manganese homeostasis may provide protection against oxidative stress, explaining the observed ex vivo reduction in virulence. In the presence of manganese and hydrogen peroxide, 5448ΔmntE mutant exhibits significantly lower survival than wild-type 5448 and the complemented mutant. We hypothesize that MntE, by maintaining homeostatic control of cytoplasmic manganese, ensures that the peroxide response repressor PerR is optimally poised to respond to hydrogen peroxide stress. Creation of a 5448ΔmntE-ΔperR double mutant rescued the oxidative stress resistance of the double mutant to wild-type levels in the presence of manganese and hydrogen peroxide. This work elucidates the mechanism for manganese toxicity within GAS and the crucial role of manganese homeostasis in maintaining GAS virulence. IMPORTANCE Manganese is traditionally viewed as a beneficial metal ion to bacteria, and it is also established that most bacteria can tolerate high concentrations of this transition metal. In this work, we show that in group A Streptococcus, mutation of the mntE locus, which encodes a transport protein of the cation diffusion facilitator (CDF) family, results in accumulation of manganese and sensitivity to this transition metal ion. The toxicity of manganese is indirect and is the result of a failure of the PerR regulator to respond to oxidative stress in the presence of high intracellular manganese concentrations. These results highlight the importance of MntE in manganese homeostasis and maintenance of an optimal manganese/iron ratio in GAS and the impact of manganese on resistance to oxidative stress and virulence.

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The Regulator PerR Is Involved in Oxidative Stress Response and Iron Homeostasis and Is Necessary for Full Virulence of Streptococcus pyogenes

Infection and Immunity ◽

10.1128/iai.70.9.4968-4976.2002 ◽

2002 ◽

Vol 70 (9) ◽

pp. 4968-4976 ◽

Cited By ~ 65

Author(s):

Susanna Ricci ◽

Robert Janulczyk ◽

Lars Björck

Keyword(s):

Oxidative Stress ◽

Streptococcus Pyogenes ◽

Stress Responses ◽

Metal Binding ◽

Iron Homeostasis ◽

Bacterial Species ◽

Transcriptional Analysis ◽

Wild Type ◽

Allelic Replacement

ABSTRACT Ferric uptake regulator (Fur) and Fur-like proteins form an important family of transcriptional regulators in many bacterial species. In this work we have characterized a Fur-like protein, the peroxide regulator PerR, in an M1 serotype of Streptococcus pyogenes. To determine the role of PerR in S. pyogenes, we inactivated the gene by allelic replacement. PerR-deficient bacteria showed 48% reduction of 55Fe incorporation from the culture medium. Transcriptional analysis revealed that mtsA, encoding a metal-binding protein of an ABC transporter in S. pyogenes, was transcribed at lower levels than were wild-type cells. Although total iron accumulation was reduced, the growth of the mutant strain was not significantly hampered. The mutant showed hyperresistance to hydrogen peroxide, and this response was induced in wild-type cells by growth in aerobiosis, suggesting that PerR acts as an oxidative stress-responsive repressor. PerR may also participate in the response to superoxide stress, as the perR mutant was more sensitive to the superoxide anion and had a reduced transcription of sodA, which encodes the sole superoxide dismutase of S. pyogenes. Complementation of the mutation with a functional perR gene restored 55Fe incorporation, response to peroxide stress, and transcription of both mtsA and sodA to levels comparable to those of wild-type bacteria. Finally, the perR mutant was attenuated in virulence in a murine air sac model of infection (P < 0.05). These results demonstrate that PerR is involved in the regulation of iron homeostasis and oxidative stress responses and that it contributes to the virulence of S. pyogenes.

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Deciphering the genetic and transcriptional basis of cross-stress responses in Escherichia coli under complex evolutionary scenarios

10.1101/010595 ◽

2014 ◽

Author(s):

Violeta Zorraquino-Salvo ◽

Semarhy Quinones-Soto ◽

Minseung Kim ◽

Navneet Rai ◽

Ilias Tagkopoulos

Keyword(s):

Escherichia Coli ◽

Stress Response ◽

Stress Responses ◽

Metal Ion ◽

Cellular Stress Response ◽

Metal Ion Binding ◽

Evolutionary Potential ◽

Specific Expression ◽

Stress Vulnerability ◽

Stress Protection

A tantalizing question in microbial physiology is the inter-dependence and evolutionary potential of cellular stress response across multiple environmental dimensions. To address this question, we comprehensively characterized the cross-stress behavior of wild-type and evolved Escherichia coli populations in five abiotic stresses (n-butanol, osmotic, alkaline, acidic, and oxidative) by performing genome-scale genetic, transcriptional and growth profiling, thus identifying 18 cases of cross-stress protection and one case of cross-stress vulnerability. We identified 18 cases of cross-stress protection and one case of cross-stress vulnerability, along with core and stress-specific networks. We tested several hypotheses regarding the effect of the stress order, stress combinations, mutation reversal and varying environments to the evolution and final cellular fitness of the respective populations. Our results argue of a common systems-level core of the stress response with several crucial implicated pathways that include metal ion binding and glycolysis/gluconeogenesis that is further complemented by a stress-specific expression program.

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Transcriptional Response of Leptospira interrogans to Iron Limitation and Characterization of a PerR Homolog

Infection and Immunity ◽

10.1128/iai.00435-10 ◽

2010 ◽

Vol 78 (11) ◽

pp. 4850-4859 ◽

Cited By ~ 54

Author(s):

Miranda Lo ◽

Gerald L. Murray ◽

Chen Ai Khoo ◽

David A. Haake ◽

Richard L. Zuerner ◽

...

Keyword(s):

Oxidative Stress ◽

Stress Response ◽

Iron Homeostasis ◽

Storage Proteins ◽

Iron Acquisition ◽

Bacterial Species ◽

Transcriptional Response ◽

Oxidative Stress Response ◽

Wild Type ◽

In The Wild

ABSTRACT Leptospirosis is a globally significant zoonosis caused by Leptospira spp. Iron is essential for growth of most bacterial species. Since iron availability is low in the host, pathogens have evolved complex iron acquisition mechanisms to survive and establish infection. In many bacteria, expression of iron uptake and storage proteins is regulated by Fur. L. interrogans encodes four predicted Fur homologs; we have constructed a mutation in one of these, la1857. We conducted microarray analysis to identify iron-responsive genes and to study the effects of la1857 mutation on gene expression. Under iron-limiting conditions, 43 genes were upregulated and 49 genes were downregulated in the wild type. Genes encoding proteins with predicted involvement in inorganic ion transport and metabolism (including TonB-dependent proteins and outer membrane transport proteins) were overrepresented in the upregulated list, while 54% of differentially expressed genes had no known function. There were 16 upregulated genes of unknown function which are absent from the saprophyte L. biflexa and which therefore may encode virulence-associated factors. Expression of iron-responsive genes was not significantly affected by mutagenesis of la1857, indicating that LA1857 is not a global regulator of iron homeostasis. Upregulation of heme biosynthetic genes and a putative catalase in the mutant suggested that LA1857 is more similar to PerR, a regulator of the oxidative stress response. Indeed, the la1857 mutant was more resistant to peroxide stress than the wild type. Our results provide insights into the role of iron in leptospiral metabolism and regulation of the oxidative stress response, including genes likely to be important for virulence.

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