OxyR Activation in Porphyromonas gingivalis in Response to a Hemin-Limited Environment

ABSTRACTPorphyromonas gingivalisis a Gram-negative obligately anaerobic bacterium associated with several forms of periodontal disease, most closely with chronic periodontitis. Previous studies demonstrated that OxyR plays an important role in the aerotolerance ofP. gingivalisby upregulating the expression of oxidative-stress genes. Increases in oxygen tension and in H2O2both induce activation of OxyR. It is also known thatP. gingivalisrequires hemin as an iron source for its growth. In this study, we found that a hemin-limited growth environment significantly enhanced OxyR activity inP. gingivalis. As a result, expression ofsod,dps, andahpCwas also upregulated. Using a chromatin immunoprecipitation quantitative PCR (qPCR) analysis, DNA binding of activated OxyR to the promoter of thesodgene was enhanced inP. gingivalisgrown under hemin-limited conditions compared to excess-hemin conditions. Cellular tolerance of H2O2was also enhanced when hemin was limited in the growth medium ofP. gingivalis. Our work supports a model in which hemin serves as a signal for the regulation of OxyR activity and indicates thatP. gingivaliscoordinately regulates expression of oxidative-stress-related genes by this hemin concentration-dependent pathway.

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Genomic Insights into Two Novel Fe(II)-Oxidizing Zetaproteobacteria Isolates Reveal Lifestyle Adaption to Coastal Marine Sediments

Applied and Environmental Microbiology ◽

10.1128/aem.01160-20 ◽

2020 ◽

Vol 86 (17) ◽

Author(s):

Nia Blackwell ◽

Casey Bryce ◽

Daniel Straub ◽

Andreas Kappler ◽

Sara Kleindienst

Keyword(s):

Oxidative Stress ◽

Marine Sediments ◽

Hydrothermal Vents ◽

Sequence Similarity ◽

Molecular Techniques ◽

Rrna Gene ◽

Coastal Marine Sediments ◽

Content Type ◽

Coastal Marine ◽

Stress Related Genes

ABSTRACT The discovery of the novel Zetaproteobacteria class greatly expanded our understanding of neutrophilic, microaerophilic microbial Fe(II) oxidation in marine environments. Despite molecular techniques demonstrating their global distribution, relatively few isolates exist, especially from low-Fe(II) environments. Furthermore, the Fe(II) oxidation pathways used by Zetaproteobacteria remain poorly understood. Here, we present the genomes (>99% genome completeness) of two Zetaproteobacteria, which are the only cultivated isolates originating from typical low-Fe [porewater Fe(II), 70 to 100 μM] coastal marine sediments. The two strains share <90% average nucleotide identity (ANI) with each other and <80% ANI with any other Zetaproteobacteria genome. The closest relatives were Mariprofundus aestuarium strain CP-5 and Mariprofundus ferrinatatus strain CP-8 (96 to 98% 16S rRNA gene sequence similarity). Fe(II) oxidation of strains KV and NF is most likely mediated by the putative Fe(II) oxidase Cyc2. Interestingly, the genome of strain KV also encodes a putative multicopper oxidase, PcoAB, which could play a role in Fe(II) oxidation, a pathway found only in two other Zetaproteobacteria genomes (Ghiorsea bivora TAG-1 and SCGC AB-602-C20). The strains show potential adaptations to fluctuating O2 concentrations, indicated by the presence of both cbb3- and aa3-type cytochrome c oxidases, which are adapted to low and high O2 concentrations, respectively. This is further supported by the presence of several oxidative-stress-related genes. In summary, our results reveal the potential Fe(II) oxidation pathways employed by these two novel chemolithoautotrophic Fe(II)-oxidizing species and the lifestyle adaptations which enable the Zetaproteobacteria to survive in coastal environments with low Fe(II) and regular redox fluctuations. IMPORTANCE Until recently, the importance and relevance of Zetaproteobacteria were mainly thought to be restricted to high-Fe(II) environments, such as deep-sea hydrothermal vents. The two novel Mariprofundus isolates presented here originate from typical low-Fe(II) coastal marine sediments. As well as being low in Fe(II), these environments are often subjected to fluctuating O2 concentrations and regular mixing by wave action and bioturbation. The discovery of two novel isolates highlights the importance of these organisms in such environments, as Fe(II) oxidation has been shown to impact nutrients and trace metals. Genome analysis of these two strains further supported their lifestyle adaptation and therefore their potential preference for coastal marine sediments, as genes necessary for surviving dynamic O2 concentrations and oxidative stress were identified. Furthermore, our analyses also expand our understanding of the poorly understood Fe(II) oxidation pathways used by neutrophilic, microaerophilic Fe(II) oxidizers.

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dprandsodin Streptococcus mutans Are Involved in Coexistence with S. sanguinis, and PerR Is Associated with Resistance to H2O2

Applied and Environmental Microbiology ◽

10.1128/aem.03306-12 ◽

2012 ◽

Vol 79 (5) ◽

pp. 1436-1443 ◽

Cited By ~ 27

Author(s):

Kei Fujishima ◽

Miki Kawada-Matsuo ◽

Yuichi Oogai ◽

Masayuki Tokuda ◽

Mitsuo Torii ◽

...

Keyword(s):

Oxidative Stress ◽

Streptococcus Mutans ◽

Dental Plaque ◽

Stress Factors ◽

Wild Type ◽

Content Type ◽

Stress Genes ◽

Large Numbers ◽

Cariogenic Bacterium ◽

Population Ratio

ABSTRACTLarge numbers of bacteria coexist in the oral cavity.Streptococcus sanguinis, one of the major bacteria in dental plaque, produces hydrogen peroxide (H2O2), which interferes with the growth of other bacteria.Streptococcus mutans, a cariogenic bacterium, can coexist withS. sanguinisin dental plaque, but to do so, it needs a means of detoxifying the H2O2produced byS. sanguinis. In this study, we investigated the association of three oxidative stress factors, Dpr, superoxide dismutase (SOD), and AhpCF, with the resistance ofS. sanguinisto H2O2. The knockout ofdprandsodsignificantly increased susceptibility to H2O2, while the knockout ofahpCFhad no apparent effect on susceptibility. In particular,dprinactivation resulted in hypersensitivity to H2O2. Next, we sought to identify the factor(s) involved in the regulation of these oxidative stress genes and found that PerR negatively regulateddprexpression. The knockout ofperRcaused increaseddprexpression levels, resulting in low-level susceptibility to H2O2compared with the wild type. Furthermore, we evaluated the roles ofperR,dpr, andsodwhenS. mutanswas cocultured withS. sanguinis. Culturing of thedprorsodmutant withS. sanguinisshowed a significant decrease in theS. mutanspopulation ratio compared with the wild type, while theperRmutant increased the ratio. Our results suggest thatdprandsodinS. mutansare involved in coexistence withS. sanguinis, and PerR is associated with resistance to H2O2in regulating the expression of Dpr.

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Analysis of Stress Responsive Genes Induced by Single-Walled Carbon Nanotubes in BJ Foreskin Cells

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.18048 ◽

2007 ◽

Vol 7 (2) ◽

pp. 584-592 ◽

Cited By ~ 2

Author(s):

Shubhashish Sarkar ◽

Chidananda Sharma ◽

Rajeshwari Yog ◽

Adaikkappan Periakaruppan ◽

Olufisayo Jejelowo ◽

...

Keyword(s):

Oxidative Stress ◽

Carbon Nanotubes ◽

Single Walled Carbon Nanotubes ◽

Consumer Products ◽

Single Walled Carbon ◽

Stress Genes ◽

Stress Responsive Genes ◽

Stress Related Genes ◽

Inducible Genes ◽

Walled Carbon Nanotubes

Nanotechnology is finding its use as a potential technology in consumer products, defense, electronics, and medical applications by exploiting the properties of nanomaterials. Single-walled carbon nanotubes are novel forms of these nanomaterials with potential for large applications. However, the toxicity studies on this material are not explored in detail and therefore limiting its use. It has been earlier reported that single-walled carbon nanotubes induces oxidative stress and also dictates activation of specific signaling pathway in keratinocytes. The present study explores the effect of single-walled carbon nanotubes on stress genes in human BJ Foreskin cells. The results show induction of oxidative stress in BJ Foreskin cells by single-walled carbon nanotubes and increase in stress responsive genes. The genes included inducible genes like HMOX1, HMOX2, and Cyp1B1. In addition we validated increase for four genes by SWCNT, namely ATM, CCNC, DNAJB4, and GADD45A by RT-PCR. Moreover results of the altered stress related genes have been discussed and that partially explains some of the toxic responses induced by single-walled carbon nanotubes.

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Fructose Increases the Expression of Uric Acid-Induced Oxidative Stress Genes, NOX4 and FOXO3, in Cultured HepG2 Cells

Current Developments in Nutrition ◽

10.1093/cdn/nzaa058_024 ◽

2020 ◽

Vol 4 (Supplement_2) ◽

pp. 1266-1266

Author(s):

Baba Mass ◽

Brea Nance ◽

Saroja Voruganti

Keyword(s):

Oxidative Stress ◽

Uric Acid ◽

Atp Depletion ◽

Subsequent Formation ◽

Stress Genes ◽

Funding Sources ◽

Nadph Oxidase 4 ◽

Custom Made ◽

Thermo Fisher Scientific ◽

Stress Related Genes

Abstract Objectives Uric acid is the final product of purine metabolism. The role of uric acid in oxidative stress is not clear. Studies have shown uric acid as antioxidant as well as pro-oxidant. High fructose sugar consumption increases uric acid levels by ATP depletion and the subsequent formation AMP which is a uric acid precursor. In our study, we investigated the effect of dose dependent treatments of fructose, uric acid, or a combination of both uric acid and fructose on expression of oxidative stress-related genes, mainly NADPH oxidase 4 (NOX4), superoxide dismutase 3 (SOD3), Forkhead Box O3 (FOXO3) and xanthine dehydrogenase (XDH) in cultured Hep G2 cells. Methods Human hepatocellular carcinoma [HEPG2] (ATCC HB8065) cells were treated with serum-free medium containing either 10 mM fructose, soluble uric acid (0.25 mM, 0.5 mM, or 0.75 mM), or a combination of fructose and uric acid. The cells were collected at the end of each incubation period (30 min, 2 and 24 hours) to extract total RNA. cDNA was synthesized from the extracted RNA. TaqMan assays were designed for use on real-rime PCR platform (QuantStudio 12 K Flex). TaqMan open array primers were custom-made by Thermo Fisher Scientific. Target quantification values were normalized against GAPDH levels and a combination of students’ t-test and ANOVA were applied. Results Soluble uric acid, either by itself or in conjunction with fructose, did not change the expression of the tested genes at 30 minutes or 2 hours. However, after 24 hours of incubation, uric acid increased the expression of NOX4 by 2 and FOXO3 by 1.5-fold (p < 0.05) whereas uric acid plus fructose-containing media increased the expression of NOX4 by 3.5 and FOXO3 by 2-fold (p < 0.05) after 24 hours of incubation as compared to control. No treatment differences were observed in the expression of SOD3. Conclusions These findings demonstrate that fructose increases the expression of uric acid-induced oxidative stress related genes. Funding Sources None.

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Role of oxyR in the Oral Anaerobe Porphyromonas gingivalis

Journal of Bacteriology ◽

10.1128/jb.188.7.2454-2462.2006 ◽

2006 ◽

Vol 188 (7) ◽

pp. 2454-2462 ◽

Cited By ~ 66

Author(s):

Patricia I. Diaz ◽

Nada Slakeski ◽

Eric C. Reynolds ◽

Renato Morona ◽

Anthony H. Rogers ◽

...

Keyword(s):

Oxidative Stress ◽

Porphyromonas Gingivalis ◽

Anaerobic Growth ◽

Phenotypic Characterization ◽

Anaerobic Microorganism ◽

Sequence Elements ◽

Stress Related Genes ◽

Insertion Sequence Elements

ABSTRACT Porphyromonas gingivalis is an anaerobic microorganism that inhabits the oral cavity, where oxidative stress represents a constant challenge. A putative transcriptional regulator associated with oxidative stress, an oxyR homologue, is known from the P. gingivalis W83 genome sequence. We used microarrays to characterize the response of P. gingivalis to H2O2 and examine the role of oxyR in the regulation of this response. Most organisms in which oxyR has been investigated are facultative anaerobes or aerobes. In contrast to the OxyR-regulated response of these microorganisms to H2O2, the main feature of the response in P. gingivalis was a concerted up-regulation of insertion sequence elements related to IS1 transposases. Common OxyR-regulated genes such as dps and ahpFC were not positively regulated in P. gingivalis in response to H2O2. However, their expression was dependent on the presence of a functional OxyR, as revealed by microarray comparison of an oxyR mutant to the wild type. Phenotypic characterization of the oxyR mutant showed that OxyR plays a role in both the resistance to H2O2 and the aerotolerance of P. gingivalis. Escherichia coli and other bacteria with more complex respiratory requirements use OxyR for regulating resistance to H2O2 and use a separate regulator for aerotolerance. In P. gingivalis, the presence of a single protein combining the two functions might be related to the comparatively smaller genome size of this anaerobic microorganism. In conclusion, these results suggest that OxyR does not act as a sensor of H2O2 in P. gingivalis but constitutively activates transcription of oxidative-stress-related genes under anaerobic growth.

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Impact of Cigarette Smoking on the Expression of Oxidative Stress-Related Genes in Cumulus Cells Retrieved from Healthy Women Undergoing IVF

International Journal of Molecular Sciences ◽

10.3390/ijms222313147 ◽

2021 ◽

Vol 22 (23) ◽

pp. 13147

Author(s):

Fani Konstantinidou ◽

Maria Cristina Budani ◽

Annalina Sarra ◽

Liborio Stuppia ◽

Gian Mario Tiboni ◽

...

Keyword(s):

Oxidative Stress ◽

Cigarette Smoking ◽

Promoter Methylation ◽

Statistical Significance ◽

Cumulus Cells ◽

Female Reproduction ◽

Stress Genes ◽

Smoking Exposure ◽

Stress Related Genes ◽

The Impact

The female reproductive system represents a sensitive target of the harmful effects of cigarette smoke, with folliculogenesis as one of the ovarian processes most affected by this exposure. The aim of this study was to analyze the impact of tobacco smoking on expression of oxidative stress-related genes in cumulus cells (CCs) from smoking and non-smoking women undergoing IVF techniques. Real time PCR technology was used to analyze the gene expression profile of 88 oxidative stress genes enclosed in a 96-well plate array. Statistical significance was assessed by one-way ANOVA. The biological functions and networks/pathways of modulated genes were evidenced by ingenuity pathway analysis software. Promoter methylation analysis was performed by pyrosequencing. Our results showed a down-regulation of 24 genes and an up-regulation of 2 genes (IL6 and SOD2, respectively) involved in defense against oxidative damage, cell cycle regulation, as well as inflammation in CCs from smoking women. IL-6 lower promoter methylation was found in CCs of the smokers group. In conclusion, the disclosed overall downregulation suggests an oxidant-antioxidant imbalance in CCs triggered by cigarette smoking exposure. This evidence adds a piece to the puzzle of the molecular basis of female reproduction and could help underlay the importance of antioxidant treatments for smoking women undergoing IVF protocols.

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Analysis of Stress Responsive Genes Induced by Single-Walled Carbon Nanotubes in BJ Foreskin Cells

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.117 ◽

2007 ◽

Vol 7 (2) ◽

pp. 584-592 ◽

Cited By ~ 46

Author(s):

Shubhashish Sarkar ◽

Chidananda Sharma ◽

Rajeshwari Yog ◽

Adaikkappan Periakaruppan ◽

Olufisayo Jejelowo ◽

...

Keyword(s):

Oxidative Stress ◽

Carbon Nanotubes ◽

Single Walled Carbon Nanotubes ◽

Consumer Products ◽

Single Walled Carbon ◽

Stress Genes ◽

Stress Responsive Genes ◽

Stress Related Genes ◽

Inducible Genes ◽

Walled Carbon Nanotubes

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Catecholamines promote the expression of virulence and oxidative stress genes in Porphyromonas gingivalis

Journal of Periodontal Research ◽

10.1111/jre.12148 ◽

2013 ◽

Vol 49 (5) ◽

pp. 660-669 ◽

Cited By ~ 16

Author(s):

T. S. Graziano ◽

P. Closs ◽

T. Poppi ◽

G. C. Franco ◽

J. R. Cortelli ◽

...

Keyword(s):

Oxidative Stress ◽

Porphyromonas Gingivalis ◽

Stress Genes ◽

And Oxidative Stress

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Transcription of Oxidative Stress Genes Is Directly Activated by SpxA1 and, to a Lesser Extent, by SpxA2 in Streptococcus mutans

Journal of Bacteriology ◽

10.1128/jb.00118-15 ◽

2015 ◽

Vol 197 (13) ◽

pp. 2160-2170 ◽

Cited By ~ 24

Author(s):

Jessica K. Kajfasz ◽

Isamar Rivera-Ramos ◽

Kathleen Scott-Anne ◽

Stacy Gregoire ◽

Jacqueline Abranches ◽

...

Keyword(s):

Oxidative Stress ◽

Oral Cavity ◽

Streptococcus Mutans ◽

Stress Responses ◽

Dominant Role ◽

Critical Role ◽

Content Type ◽

Stress Genes

ABSTRACTThe SpxA1 and SpxA2 (formerly SpxA and SpxB) transcriptional regulators ofStreptococcus mutansare members of a highly conserved family of proteins found inFirmicutes, and they were previously shown to activate oxidative stress responses. In this study, we showed that SpxA1 exerts substantial positive regulatory influence over oxidative stress genes following exposure to H2O2, while SpxA2 appears to have a secondary regulatory role.In vitrotranscription (IVT) assays using purified SpxA1 and/or SpxA2 showed that SpxA1 and, less often, SpxA2 directly activate transcription of some of the major oxidative stress genes. Addition of equimolar concentrations of SpxA1 and SpxA2 to the IVT reactions neither enhanced transcription of the tested genes nor disrupted the dominant role of SpxA1. Substitution of a conserved glycine residue (G52) present in both Spx proteins by arginine (SpxG52R) resulted in strains that phenocopied the Δspxstrains. Moreover, addition of purified SpxA1G52Rcompletely failed to activate transcription ofahpC,sodA, andtpx, further confirming that the G52 residue is critical for Spx functionality.IMPORTANCEStreptococcus mutansis a pathogen associated with the formation of dental caries in humans. Within the oral cavity,S. mutansroutinely encounters oxidative stress. Our previous data revealed that two regulatory proteins, SpxA1 and SpxA2 (formerly SpxA and SpxB), bear high homology to the Spx regulator that has been characterized as a critical activator of oxidative stress genes inBacillus subtilis. In this report, we prove that Spx proteins ofS. mutansdirectly activate transcription of genes involved in the oxidative stress response, though SpxA1 appears to have a more dominant role than SpxA2. Therefore, the Spx regulators play a critical role in the ability ofS. mutansto thrive within the oral cavity.

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Loss of SigB in Listeria monocytogenes Strains EGD-e and 10403S Confers Hyperresistance to Hydrogen Peroxide in Stationary Phase under Aerobic Conditions

Applied and Environmental Microbiology ◽

10.1128/aem.00709-16 ◽

2016 ◽

Vol 82 (15) ◽

pp. 4584-4591 ◽

Cited By ~ 13

Author(s):

Marcia Boura ◽

Ciara Keating ◽

Kevin Royet ◽

Ranju Paudyal ◽

Beth O'Donoghue ◽

...

Keyword(s):

Oxidative Stress ◽

Hydrogen Peroxide ◽

Listeria Monocytogenes ◽

Stationary Phase ◽

Stress Resistance ◽

Wild Type ◽

Content Type ◽

Stress Genes ◽

Reverse Transcription Pcr ◽

Stress Gene

ABSTRACTSigB is the main stress gene regulator inListeria monocytogenesaffecting the expression of more than 150 genes and thus contributing to multiple-stress resistance. Despite its clear role in most stresses, its role in oxidative stress is uncertain, as results accompanying the loss ofsigBrange from hyperresistance to hypersensitivity. Previously, these differences have been attributed to strain variation. In this study, we show conclusively that unlike for all other stresses, loss ofsigBresults in hyperresistance to H2O2(more than 8 log CFU ml−1compared to the wild type) in aerobically grown stationary-phase cultures ofL. monocytogenesstrains 10403S and EGD-e. Furthermore, growth at 30°C resulted in higher resistance to oxidative stress than that at 37°C. Oxidative stress resistance seemed to be higher with higher levels of oxygen. Under anaerobic conditions, the loss of SigB in 10403S did not affect survival against H2O2, while in EGD-e, it resulted in a sensitive phenotype. During exponential phase, minor differences occurred, and this result was expected due to the absence ofsigBtranscription. Catalase tests were performed under all conditions, and stronger catalase results corresponded well with a higher survival rate, underpinning the important role of catalase in this phenotype. Furthermore, we assessed the catalase activity in protein lysates, which corresponded with the catalase tests and survival. In addition, reverse transcription-PCR (RT-PCR) showed no differences in transcription between the wild type and the ΔsigBmutant in various oxidative stress genes. Further investigation of the molecular mechanism behind this phenotype and its possible consequences for the overall phenotype ofL. monocytogenesare under way.IMPORTANCESigB is the most important stress gene regulator inL. monocytogenesand other Gram-positive bacteria. Its increased expression during stationary phase results in resistance to multiple stresses. However, despite its important role in general stress resistance, its expression is detrimental for the cell in the presence of oxidative stress, as it promotes hypersensitivity against hydrogen peroxide. This peculiar phenotype is an important element of the physiology ofL. monocytogenes, and it might help us explain the behavior of this organism in environments where oxidative stress is present.

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