The Streptococcus mutans vicX Gene Product Modulates gtfB/C Expression, Biofilm Formation, Genetic Competence, and Oxidative Stress Tolerance

ABSTRACT Streptococcus mutans is considered one of the primary etiologic agents of dental caries. Previously, we characterized the VicRK two-component signal transduction system, which regulates multiple virulence factors of S. mutans. In this study, we focused on the vicX gene of the vicRKX tricistronic operon. To characterize vicX, we constructed a nonpolar deletion mutation in the vicX coding region in S. mutans UA159. The growth kinetics of the mutant (designated SmuvicX) showed that the doubling time was longer and that there was considerable sensitivity to paraquat-induced oxidative stress. Supplementing a culture of the wild-type UA159 strain with paraquat significantly increased the expression of vicX (P < 0.05, as determined by analysis of variance [ANOVA]), confirming the role of this gene in oxidative stress tolerance in S. mutans. Examination of mutant biofilms revealed architecturally altered cell clusters that were seemingly denser than the wild-type cell clusters. Interestingly, vicX-deficient cells grown in a glucose-supplemented medium exhibited significantly increased glucosyltransferase B/C (gtfB/C) expression compared with the expression in the wild type (P < 0.05, as determined by ANOVA). Moreover, a sucrose-dependent adhesion assay performed using an S. mutans GS5-derived vicX null mutant demonstrated that the adhesiveness of this mutant was enhanced compared with that of the parent strain and isogenic mutants of the parent strain lacking gtfB and/or gtfC. Also, disruption of vicX reduced the genetic transformability of the mutant approximately 10-fold compared with that of the parent strain (P < 0.05, as determined by ANOVA). Collectively, these findings provide insight into important phenotypes controlled by the vicX gene product that can impact S. mutans pathogenicity.

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Isolation and characterization of an atypical LEA gene (IpLEA) from Ipomoea pes-caprae conferring salt/drought and oxidative stress tolerance

Scientific Reports ◽

10.1038/s41598-019-50813-w ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Jiexuan Zheng ◽

Huaxiang Su ◽

Ruoyi Lin ◽

Hui Zhang ◽

Kuaifei Xia ◽

...

Keyword(s):

Oxidative Stress ◽

Stress Tolerance ◽

Abiotic Stresses ◽

Expression Patterns ◽

Large Family ◽

Regulatory Elements ◽

Pcr Analysis ◽

Wild Type ◽

Oxidative Stress Tolerance ◽

Isolation And Characterization

Abstract Late embryogenesis abundant (LEA) proteins belong to a large family that exists widely in plants and is mainly involved in desiccation processes during plant development or in the response to abiotic stresses. Here, we reported on an atypical LEA gene (IpLEA) related to salt tolerance from Ipomoea pes-caprae L. (Convolvulaceae). Sequence analysis revealed that IpLEA belongs to the LEA_2 (PF03168) group. IpLEA was shown to have a cytoplasmic localization pattern. Quantitative reverse transcription PCR analysis showed that IpLEA was widely expressed in different organs of the I. pes-caprae plants, and the expression levels increased following salt, osmotic, oxidative, freezing, and abscisic acid treatments. Analysis of the 1,495 bp promoter of IpLEA identified distinct cis-acting regulatory elements involved in abiotic stress. Induction of IpLEA improved Escherichia coli growth performance compared with the control under abiotic stresses. To further assess the function of IpLEA in plants, transgenic Arabidopsis plants overexpressing IpLEA were generated. The IpLEA-overexpressing Arabidopsis seedlings and adult plants showed higher tolerance to salt and drought stress than the wild-type. The transgenic plants also showed higher oxidative stress tolerance than the wild-type Arabidopsis. Furthermore, the expression patterns of a series of stress-responsive genes were affected. The results indicate that IpLEA is involved in the plant response to salt and drought, probably by mediating water homeostasis or by acting as a reactive oxygen species scavenger, thereby influencing physiological processes under various abiotic stresses in microorganisms and plants.

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Phenotyping dauer juvenile oxidative stress tolerance, longevity and persistence within wild type and inbred lines of the entomopathogenic nematode Heterorhabditis bacteriophora

Nematology ◽

10.1163/15685411-00003100 ◽

2017 ◽

Vol 19 (8) ◽

pp. 971-986 ◽

Cited By ~ 1

Author(s):

Nanette Hope Sumaya ◽

Sitaram Aryal ◽

Bart Vandenbossche ◽

Mike Barg ◽

Verena Doerfler ◽

...

Keyword(s):

Oxidative Stress ◽

Shelf Life ◽

Stress Tolerance ◽

Entomopathogenic Nematode ◽

Heterorhabditis Bacteriophora ◽

Inbred Lines ◽

Wild Type ◽

Oxidative Stress Tolerance ◽

Metabolic Imbalance ◽

In Transit

The commercial use of the entomopathogenic nematodeHeterorhabditis bacteriophoraas a biocontrol agent against noxious insects is limited due to its relatively short shelf-life. Longevity of dauer juveniles (DJ) during storage and in transit to end users is considerably restricted by environmental stresses. As a derivative stress triggered by environmental factors, oxidative stress causes a strong internal metabolic imbalance leading to lifespan reduction. In this study, the relation between DJ oxidative stress tolerance and longevity inH. bacteriophorawas investigated at 25 and 7°C. A strong and significant correlation between DJ oxidative stress tolerance and longevity during storage in Ringer’s solution ( at 7°C; at 25°C) was recorded. Phenotyping of these traits was performed for 40H. bacteriophorawild type strain and inbred line collections. At 25°C, the mean time survived in Ringer’s by 50% of the DJ (MTS50) ranged from 21 to 57 days, whereas under oxidative stress, survival was from 3 to 22 days. At 7°C, a maximum MTS50of 94 days was assessed when DJ were stored in Ringer’s, while the maximum MTS50was only 25 days with oxidative stress induction. The heritability of DJ tolerance to oxidative stress, determined by using homozygous inbred lines, is high (), an indication of a high probability for successful selective breeding. In a subset of preselectedH. bacteriophorainbred lines, DJ oxidative stress tolerance correlated with the DJ survival (persistence) after application to sand (). The study provides fundamental data required for a genetic breeding programme to produce hybrids with improved stress tolerance and prolonged shelf-life and soil persistence.

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Identification of the Streptococcus mutans LytST two-component regulon reveals its contribution to oxidative stress tolerance

BMC Microbiology ◽

10.1186/1471-2180-12-187 ◽

2012 ◽

Vol 12 (1) ◽

pp. 187 ◽

Cited By ~ 40

Author(s):

Sang-Joon Ahn ◽

Ming-Da Qu ◽

Elisha Roberts ◽

Robert A Burne ◽

Kelly C Rice

Keyword(s):

Oxidative Stress ◽

Stress Tolerance ◽

Streptococcus Mutans ◽

Oxidative Stress Tolerance ◽

Two Component

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Understanding the Streptococcus mutans Cid/Lrg System through CidB Function

Applied and Environmental Microbiology ◽

10.1128/aem.01499-16 ◽

2016 ◽

Vol 82 (20) ◽

pp. 6189-6203 ◽

Cited By ~ 23

Author(s):

Sang-Joon Ahn ◽

Kelly C. Rice

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Stress Tolerance ◽

Streptococcus Mutans ◽

Essential Elements ◽

Genomic Islands ◽

Aerobic Growth ◽

Oxidative Stress Tolerance ◽

Content Type ◽

Biofilm Development

ABSTRACTTheStreptococcus mutanslrgABandcidABoperons have been previously described as a potential model system to dissect the complexity of biofilm development and virulence ofS. mutans. Herein, we have attempted to further characterize the Cid/Lrg system by focusing on CidB, which has been shown to be critical for the ability ofS. mutansto survive and persist in a nonpreferred oxygen-enriched condition. We have found that the expression level ofcidBis critical to oxidative stress tolerance ofS. mutans, most likely by impactinglrgexpression. Intriguingly, the impaired aerobic growth phenotype of thecidBmutant could be restored by the additional loss of either CidA or LrgA. Growth-dependent expression ofcidandlrgwas demonstrated to be tightly under the control of both CcpA and the VicKR two-component system (TCS), regulators known to play an essential role in controlling major catabolic pathways and cell envelope homeostasis, respectively. RNA sequencing (RNA-Seq) analysis revealed that mutation ofcidBresulted in global gene expression changes, comprising major domains of central metabolism and virulence processes, particularly in those involved with oxidative stress resistance. Loss of CidB also significantly changed the expression of genes related to genomic islands (GI) TnSmu1 and TnSmu2, the CRISPR (clustered regularly interspaced short palindromic repeats)-Cas system, and toxin-antitoxin (T/A) modules. Taken together, these data show that CidB impinges on the stress response, as well as the fundamental cellular physiology ofS. mutans, and further suggest a potential link between Cid/Lrg-mediated cellular processes,S. mutanspathogenicity, and possible programmed growth arrest and cell death mechanisms.IMPORTANCEThe ability ofStreptococcus mutansto survive a variety of harmful or stressful conditions and to emerge as a numerically significant member of stable oral biofilm communities are essential elements for its persistence and cariogenicity. In this study, the homologouscidABandlrgABoperons, previously identified as being highly balanced and coordinated duringS. mutansaerobic growth, were further characterized through the functional and transcriptomic analysis of CidB. Precise control of CidB levels is shown to impact the expression oflrg, oxidative stress tolerance, major metabolic domains, and the molecular modules linked to cell death and lysis. This study advances our understanding of the Cid/Lrg system as a key player in the integration of complex environmental signals (such as oxidative stress) into the regulatory networks that modulateS. mutansvirulence and cell homeostasis.

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Faculty Opinions recommendation of Posttranscriptional induction of two Cu/Zn superoxide dismutase genes in Arabidopsis is mediated by downregulation of miR398 and important for oxidative stress tolerance.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1033617.387847 ◽

2006 ◽

Author(s):

Eric Lam

Keyword(s):

Oxidative Stress ◽

Superoxide Dismutase ◽

Stress Tolerance ◽

Oxidative Stress Tolerance

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Polyphenolic Compound from Brown Macroalga Padina tetrastromatica Imparts Oxidative Stress Tolerance in SH‐SY5Y, RAW 264.7, HeLa Cell Lines and in Caenorhabditis elegans

ChemistrySelect ◽

10.1002/slct.201900607 ◽

2019 ◽

Vol 4 (20) ◽

pp. 6342-6347

Author(s):

Sameer Kumar Rai ◽

Bhardwaj Smriti ◽

Sathaiah Gunaseelan ◽

Balasubramaniem Ashokkumar ◽

Perumal Varalakshmi

Keyword(s):

Oxidative Stress ◽

Caenorhabditis Elegans ◽

Hela Cell ◽

Stress Tolerance ◽

Raw 264.7 ◽

Polyphenolic Compound ◽

Oxidative Stress Tolerance ◽

Padina Tetrastromatica ◽

Hela Cell Lines ◽

Brown Macroalga

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Essential Function of the Pseudorabies Virus UL36 Gene Product Is Independent of Its Interaction with the UL37 Protein

Journal of Virology ◽

10.1128/jvi.78.21.11879-11889.2004 ◽

2004 ◽

Vol 78 (21) ◽

pp. 11879-11889 ◽

Cited By ~ 89

Author(s):

Walter Fuchs ◽

Barbara G. Klupp ◽

Harald Granzow ◽

Thomas C. Mettenleiter

Keyword(s):

Gene Product ◽

Pseudorabies Virus ◽

Rabbit Kidney ◽

Tegument Protein ◽

Wild Type ◽

Coding Region ◽

Ordered Structures ◽

Ca 50 ◽

Essential Function ◽

Full Length Clone

ABSTRACT The large tegument protein encoded by the UL36 gene of pseudorabies virus (PrV) physically interacts with the product of the adjacent UL37 gene (B. G. Klupp, W. Fuchs, H. Granzow, R. Nixdorf, and T. C. Mettenleiter, J. Virol. 76:3065-3071, 2002). To analyze UL36 function, two PrV recombinants were generated by mutagenesis of an infectious PrV full-length clone in Escherichia coli: PrV-ΔUL36F exhibited a deletion of virtually the complete UL36 coding region, whereas PrV-UL36BSF contained two in-frame deletions of 238 codons spanning the predicted UL37 binding domain. Coimmunoprecipitation experiments confirmed that the mutated gene product of PrV-UL36BSF did not interact with the UL37 protein. Like the previously described PrV-ΔUL37 (B. G. Klupp, H. Granzow, and T. C. Mettenleiter, J. Virol. 75:8927-8936, 2001) but in contrast to PrV-ΔUL36F, PrV-UL36BSF was able to replicate in rabbit kidney (RK13) cells, although maximum virus titers were reduced ca. 50-fold and plaque diameters were reduced by ca. 45% compared to wild-type PrV. PrV-ΔUL36F was able to productively replicate after repair of the deleted gene or in a trans-complementing cell line. Electron microscopy of infected RK13 cells revealed that PrV-UL36BSF and phenotypically complemented PrV-ΔUL36F were capable of nucleocapsid formation and egress from the nucleus by primary envelopment and deenvelopment at the nuclear membrane. However, reenvelopment of nucleocapsids in the cytoplasm was blocked. Only virus-like particles without capsids were released efficiently from cells. Interestingly, cytoplasmic nucleocapsids of PrV-UL36BSF but not of PrV-ΔUL36F were found in large ordered structures similar to those which had previously been observed with PrV-ΔUL37. In summary, our results demonstrate that the interaction between the UL36 and UL37 proteins is important but not strictly essential for the formation of secondary enveloped, infectious PrV particles. Furthermore, UL36 possesses an essential function during virus replication which is independent of its ability to bind the UL37 protein.

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