Acid‐adaptive Responses of<i>Streptococcus Mutans</i>, and Mechanisms of Integration With Oxidative Stress

Quivey, Robert G.; Faustoferri, Roberta C.; Santiago, Brendaliz; Baker, Jonathon L.; Cross, Benjamin; Xiao, Jin

doi:10.1002/9781119004813.ch88

Cited by 2 publications

(2 citation statements)

References 113 publications

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“…Moreover, addition of antioxidants did not alleviate aerobic growth defect in the GBS nox-2 mutant, however, it could be restored by the addition of exogenous unsaturated fatty acids. Previous reports in streptococci have related membrane fatty acid composition with acid tolerance (Kajfasz and Quivey, 2011 ; Quivey et al, 2016 ). Even more, concurrent acid and oxidative stresses have been shown to be associated with elevated unsaturated fatty acid abundance (Derr et al, 2012 ).…”

Section: Bacterial Mechanisms To Cope With the Acid Stressmentioning

confidence: 97%

Acid Stress Response Mechanisms of Group B Streptococci

Shabayek

Spellerberg

2017

Front. Cell. Infect. Microbiol.

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Group B streptococcus (GBS) is a leading cause of neonatal mortality and morbidity in the United States and Europe. It is part of the vaginal microbiota in up to 30% of pregnant women and can be passed on to the newborn through perinatal transmission. GBS has the ability to survive in multiple different host niches. The pathophysiology of this bacterium reveals an outstanding ability to withstand varying pH fluctuations of the surrounding environments inside the human host. GBS host pathogen interations include colonization of the acidic vaginal mucosa, invasion of the neutral human blood or amniotic fluid, breaching of the blood brain barrier as well as survival within the acidic phagolysosomal compartment of macrophages. However, investigations on GBS responses to acid stress are limited. Technologies, such as whole genome sequencing, genome-wide transcription and proteome mapping facilitate large scale identification of genes and proteins. Mechanisms enabling GBS to cope with acid stress have mainly been studied through these techniques and are summarized in the current review

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Section: Bacterial Mechanisms To Cope With the Acid Stressmentioning

confidence: 97%

Acid Stress Response Mechanisms of Group B Streptococci

Shabayek

Spellerberg

2017

Front. Cell. Infect. Microbiol.

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“…Our RNA-Seq results showed that several genes involved in reactive oxygen species (ROS) detoxification possibly regulated by OxyR, such as ZMO0918 (catalase) and ZMO1060 (superoxide dismutase), were significantly upregulated in all strains, especially in ZM4 at pH 3.8 compared to pH 6.2, while ZMO1211 (glutathione reductase) was significantly upregulated at pH 3.8 only in wild-type ZM4 (Additional file 3: Table S2). Since acidic pH could induce a secondary oxidative stress and the acid tolerance response overlaps with the oxidative stress response [59,60], the mutation in oxyR could contribute to the acidic pH tolerance in mutant strains.…”

Section: Glucose Used (G/l)mentioning

confidence: 99%

Development and characterization of acidic-pH-tolerant mutants of Zymomonas mobilis through adaptation and next-generation sequencing-based genome resequencing and RNA-Seq

Yang

Tang

et al. 2020

Biotechnol Biofuels

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Background: Acid pretreatment is a common strategy used to break down the hemicellulose component of the lignocellulosic biomass to release pentoses, and a subsequent enzymatic hydrolysis step is usually applied to release hexoses from the cellulose. The hydrolysate after pretreatment and enzymatic hydrolysis containing both hexoses and pentoses can then be used as substrates for biochemical production. However, the acid-pretreated liquor can also be directly used as the substrate for microbial fermentation, which has an acidic pH and contains inhibitory compounds generated during pretreatment. Although the natural ethanologenic bacterium Zymomonas mobilis can grow in a broad range of pH 3.5 ~ 7.5, cell growth and ethanol fermentation are still affected under acidic-pH conditions below pH 4.0. Results: In this study, adaptive laboratory evolution (ALE) strategy was applied to adapt Z. mobilis under acidic-pH conditions. Two mutant strains named 3.6M and 3.5M with enhanced acidic pH tolerance were selected and confirmed, of which 3.5M grew better than ZM4 but worse than 3.6M in acidic-pH conditions that is served as a reference strain between 3.6M and ZM4 to help unravel the acidic-pH tolerance mechanism. Mutant strains 3.5M and 3.6M exhibited 50 ~ 130% enhancement on growth rate, 4 ~ 9 h reduction on fermentation time to consume glucose, and 20 ~ 63% improvement on ethanol productivity than wild-type ZM4 at pH 3.8. Next-generation sequencing (NGS)-based whole-genome resequencing (WGR) and RNA-Seq technologies were applied to unravel the acidic-pH tolerance mechanism of mutant strains. WGR result indicated that compared to wild-type ZM4, 3.5M and 3.6M have seven and five single nucleotide polymorphisms (SNPs), respectively, among which four are shared in common. Additionally, RNA-Seq result showed that the upregulation of genes involved in glycolysis and the downregulation of flagellar and mobility related genes would help generate and redistribute cellular energy to resist acidic pH while keeping normal biological processes in Z. mobilis. Moreover, genes involved in RND efflux pump, ATP-binding cassette

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Acid‐adaptive Responses ofStreptococcus Mutans, and Mechanisms of Integration With Oxidative Stress

Cited by 2 publications

References 113 publications

Acid Stress Response Mechanisms of Group B Streptococci

Acid Stress Response Mechanisms of Group B Streptococci

Development and characterization of acidic-pH-tolerant mutants of Zymomonas mobilis through adaptation and next-generation sequencing-based genome resequencing and RNA-Seq

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