Identification of an operon involved in fluoride resistance in Enterobacter cloacae FRM

Liu, Xiaoqing; Tian, Jian; Liu, Lihui; Zhu, Tao; Yu, Xiaoxia; Chu, Xiaoyu; Yao, Bin; Wu, Ningfeng; Fan, Yanting

doi:10.1038/s41598-017-06988-1

Cited by 17 publications

(20 citation statements)

References 39 publications

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“…Previous studies have identified genes that contribute to fluoride resistance in different species, and several gene candidates have been found in bacteria such as oral streptococci and Enterobacter cloacae FRM [ 13 , 25 ]. Genome sequencing was performed to identify mutation(s) contributing to the resistance phenotype of the FR strain.…”

Section: Resultsmentioning

confidence: 99%

“…Clinical studies with an S. mutans FR strain isolated from radiation-treated cancer patients with xerostomia (dry mouth) have suggested that the fluoride resistance is unstable and transient via horizontal gene transfer of plasmid DNAs [ 10 , 11 ]. Further, to better understand the resistance mechanism, other research groups have attempted to create FR strains of S. mutans or Enterobacter cloacae species under laboratory conditions [ 12 , 13 , 14 ]. The laboratory-derived FR strains harboring multiple single-nucleotide polymorphisms (SNPs) present stable, permanent resistance.…”

Section: Introductionmentioning

confidence: 99%

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Genetic Mutations That Confer Fluoride Resistance Modify Gene Expression and Virulence Traits of Streptococcus mutans

2021

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Fluoride is an inorganic monatomic anion that is widely used as an anti-cariogenic agent for the control of caries development. The aims of this study were to identify the mutated genes that give rise to fluoride-resistant (FR) strains of the cariogenic pathogen Streptococcus mutans and explore how genetic alterations in the genome of an S. mutans FR strain optimize the metabolism(s) implicated in the expression of virulence-associated traits. Here, we derived an S. mutans FR strain from a wild-type UA159 strain by continuous shifts to a medium supplemented with increasing concentrations of fluoride. The FR strain exhibited a slow growth rate and low yield under aerobic and oxidative stress conditions and was highly sensitive to acid stress. Notably, microscopy observation displayed morphological changes in which the FR strain had a slightly shorter cell length. Next, using the sequencing analyses, we found six mutations in the FR genome, which decreased the gene expression of the phosphoenolpyruvate-dependent phosphotransferase system (PTS). Indeed, the ability to intake carbohydrates was relatively reduced in the FR strain. Collectively, our results provide evidence that the genetic mutations in the genome of the FR strain modulate the expression of gene(s) for carbon metabolism(s) and cellular processes, leading to diminished fitness with respect to virulence and persistence.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Genetic Mutations That Confer Fluoride Resistance Modify Gene Expression and Virulence Traits of Streptococcus mutans

2021

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“…Fluoride riboswitch located upstream of HSERO_RS12335 coding the voltagegated chloride channel protein. This riboswitch has been experimentally verified by [63] detecting fluoride and triggering the expression of genes that can help Enterobacter cloacae FRM to mitigate fluoride toxicity, using a fluorine carrier to expel fluoride from the cells.…”

Section: Srnas Of H Seropedicae Smr1mentioning

confidence: 97%

In silico prediction and expression profile analysis of small non-coding RNAs in Herbaspirillum seropedicae SmR1

et al. 2020

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Background: Herbaspirillum seropedicae is a diazotrophic bacterium from the β-proteobacteria class that colonizes endophytically important gramineous species, promotes their growth through phytohormone-dependent stimulation and can express nif genes and fix nitrogen inside plant tissues. Due to these properties this bacterium has great potential as a commercial inoculant for agriculture. The H. seropedicae SmR1 genome is completely sequenced and annotated but despite the availability of diverse structural and functional analysis of this genome, studies involving small non-coding RNAs (sRNAs) has not yet been done. We have conducted computational prediction and RNA-seq analysis to select and confirm the expression of sRNA genes in the H. seropedicae SmR1 genome, in the presence of two nitrogen independent sources and in presence of naringenin, a flavonoid secreted by some plants.Results: This approach resulted in a set of 117 sRNAs distributed in riboswitch, cis-encoded and transencoded categories and among them 20 have Rfam homologs. The housekeeping sRNAs tmRNA, ssrS and 4.5S were found and we observed that a large number of sRNAs are more expressed in the nitrate condition rather than the control condition and in the presence of naringenin. Some sRNAs expression were confirmed in vitro and this work contributes to better understand the post transcriptional regulation in this bacterium. Conclusions: H. seropedicae SmR1 express sRNAs in the presence of two nitrogen sources and/or in the presence of naringenin. The functions of most of these sRNAs remains unknown but their existence in this bacterium confirms the evidence that sRNAs are involved in many different cellular activities to adapt to nutritional and environmental changes.

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“…Moreover, it has been shown that fluoride interferes with the acid production and secretion of GTFs in S. mutans and inactivates the virulence factors of cariogenic bacteria in dental plaque [15]. As shown in multiple studies, fluoride-resistant strains, including S. mutans, Streptococcus sobrinus, Streptococcus salivarius, and Enterobacter cloacae, have also been generated under laboratory conditions via prolonged exposure to high concentrations of sodium fluoride [16][17][18][19][20]. Importantly, some investigations showed that fluoride resistance can be a permanently acquired trait due to chromosomal alterations rather than a transient consequence [19][20][21][22].…”

Section: Anticariogenic Potential Of Korean Native Plant Extracts Agamentioning

confidence: 99%

“…As shown in multiple studies, fluoride-resistant strains, including S. mutans, Streptococcus sobrinus, Streptococcus salivarius, and Enterobacter cloacae, have also been generated under laboratory conditions via prolonged exposure to high concentrations of sodium fluoride [16][17][18][19][20]. Importantly, some investigations showed that fluoride resistance can be a permanently acquired trait due to chromosomal alterations rather than a transient consequence [19][20][21][22]. Using a whole-genome shotgun (WGS) sequencing technique, Liao et al [19] discovered single nucleotide polymorphisms (SNPs) were caused by nonsynonymous substitution in five genes (smc, furR, pyk, holA, and perB) and in the intergenic regions of genes related to a fluoride antiporter in a fluoride-resistant S. mutans strain.…”

Section: Anticariogenic Potential Of Korean Native Plant Extracts Agamentioning

confidence: 99%

Anticariogenic Potential of Korean Native Plant Extracts against Streptococcus mutans

et al. 2019

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Numerous chemically synthesized compounds are widely used in oral hygiene products. However, due to their potential risk, there is a need to improve the safety and quality of dental care by seeking alternative control agents such as those naturally found in plant materials. Here we assessed antibacterial potentials of extracts from 100 species of Korean native plants against Streptococcus mutans on cariogenesis. Among those, extracts from five plants (Arctii Fructus, Caryopteris incana, Aralia continentalis, Symplocarpus renifolius, and Lamium amplexicaule) showed a growth inhibition of S. mutans. The five extracts were further individually evaluated for their minimal inhibitory concentration and minimal bactericidal concentration. Interestingly, a synergistic antibacterial activity was observed with the combination of sodium fluoride and the plant extracts. To determine the anti-biofilm activity of plant extracts, S. mutans was treated with increasing concentrations of the extracts in the range from 1250 to 3750 µg/mL. When S. mutans was grown in the defined biofilm medium containing the individual extracts of 47 species, the biofilm amount markedly decreased compared to that of a negative control. Notably, the extract of S. renifolius significantly downregulated the gtf and spaP genes for synthesis of glucan and adhesive proteins in S. mutans, and L. amplexicaule decreased the expression of gtfD gene. Therefore, these results demonstrate that the five plant extracts modulate survival and pathogenesis of S. mutans by growth inhibition and downregulation of the gene(s) implicated in biofilm formation.

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Identification of an operon involved in fluoride resistance in Enterobacter cloacae FRM

Cited by 17 publications

References 39 publications

Genetic Mutations That Confer Fluoride Resistance Modify Gene Expression and Virulence Traits of Streptococcus mutans

Genetic Mutations That Confer Fluoride Resistance Modify Gene Expression and Virulence Traits of Streptococcus mutans

In silico prediction and expression profile analysis of small non-coding RNAs in Herbaspirillum seropedicae SmR1

Anticariogenic Potential of Korean Native Plant Extracts against Streptococcus mutans

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