scholarly journals ClpP participates in stress tolerance, biofilm formation, antimicrobial tolerance, and virulence of Enterococcus faecalis

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jinxin Zheng ◽  
Yang Wu ◽  
Zhiwei Lin ◽  
Guangfu Wang ◽  
Sibo Jiang ◽  
...  
2020 ◽  
Author(s):  
Jinxin Zheng ◽  
Yang Wu ◽  
Zhiwei Lin ◽  
Guangfu Wang ◽  
Sibo Jiang ◽  
...  

Abstract Background ClpP is important for bacterial growth and plays an indispensable role in cellular protein quality control systems by refolding or degrading damaged proteins, but the physiological significance of ClpP in Enterococcus faecalis remains obscure. A clpP deletion mutant (△ clpP ) was constructed using the E. faecalis OG1RF strain to clarify the effect of ClpP on E. faecalis. The global abundance of proteins was determined by a mass spectrometer with tandem mass tag labeling. Results The Δ clpP mutant strain showed impaired growth at 20°C or 45°C at 5% NaCl or 2 mM H 2 O 2 . The number of surviving Δ clpP mutants decreased after exposure to the high concentration (50× minimal inhibitory concentration) of linezolid or minocycline for 96 h. The Δ clpP mutant strain also demonstrated decreased biofilm formation but increased virulence in a Galleria mellonella model. The mass spectrometry proteomics data indicated that the abundances of 135 proteins changed (111 increased, 24 decreased) in the Δ clpP mutant strain. Among those, the abundances of stress response or virulence relating proteins: FsrA response regulator, gelatinase GelE, regulatory protein Spx ( spxA ), heat-inducible transcription repressor HrcA, transcriptional regulator CtsR, ATPase/chaperone ClpC, acetyl esterase/lipase, and chaperonin GroEL increased in the Δ clpP mutant strain; however, the abundances of ribosomal protein L4/L1 family protein ( rplD ), ribosomal protein L7/L12 ( rplL2 ), 50S ribosomal protein L13 ( rplM ), L18 ( rplR ), L20 ( rplT ), 30S ribosomal protein S14 ( rpsN2 ) and S18 ( rpsR ) all decreased. The abundances of biofilm formation-related adapter protein MecA increased, while the abundances of dihydroorotase ( pyrC ), orotate phosphoribosyltransferase ( pyrE ), and orotidine-5'-phosphate decarboxylase ( pyrF ) all decreased in the Δ clpP mutant strain. Conclusion The present study demonstrates that ClpP participates in stress tolerance, biofilm formation, antimicrobial tolerance, and virulence of E. faecalis.


2020 ◽  
Author(s):  
Jinxin Zheng ◽  
Yang Wu ◽  
Zhiwei Lin ◽  
Guangfu Wang ◽  
Sibo Jiang ◽  
...  

Abstract Background ClpP is important for bacterial growth and plays an indispensable role in cellular protein quality control systems by refolding or degrading damaged proteins, but the physiological significance of ClpP in Enterococcus faecalis remains obscure. A clpP deletion mutant (△ clpP ) was constructed using the E. faecalis OG1RF strain to clarify the effect of ClpP on E. faecalis. The global abundance of proteins was determined by a mass spectrometer with tandem mass tag labeling.Results The Δ clpP mutant strain showed impaired growth at 20°C or 45°C at 5% NaCl or 2 mM H 2 O 2 . The number of surviving Δ clpP mutants decreased after exposure to the high concentration (50× minimal inhibitory concentration) of linezolid or minocycline for 96 h. The Δ clpP mutant strain also demonstrated decreased biofilm formation but increased virulence in a Galleria mellonella model. The mass spectrometry proteomics data indicated that the abundances of 135 proteins changed (111 increased, 24 decreased) in the Δ clpP mutant strain. Among those, the abundances of stress response or virulence relating proteins: FsrA response regulator, gelatinase GelE, regulatory protein Spx ( spxA ), heat-inducible transcription repressor HrcA, transcriptional regulator CtsR, ATPase/chaperone ClpC, acetyl esterase/lipase, and chaperonin GroEL increased in the Δ clpP mutant strain; however, the abundances of ribosomal protein L4/L1 family protein ( rplD ), ribosomal protein L7/L12 ( rplL2 ), 50S ribosomal protein L13 ( rplM ), L18 ( rplR ), L20 ( rplT ), 30S ribosomal protein S14 ( rpsN2 ) and S18 ( rpsR ) all decreased. The abundances of biofilm formation-related adapter protein MecA increased, while the abundances of dihydroorotase ( pyrC ), orotate phosphoribosyltransferase ( pyrE ), and orotidine-5'-phosphate decarboxylase ( pyrF ) all decreased in the Δ clpP mutant strain.Conclusion The present study demonstrates that ClpP participates in stress tolerance, biofilm formation, antimicrobial tolerance, and virulence of E. faecalis.


PLoS ONE ◽  
2013 ◽  
Vol 8 (1) ◽  
pp. e53600 ◽  
Author(s):  
Fang Xie ◽  
Yanhe Zhang ◽  
Gang Li ◽  
Long Zhou ◽  
Siguo Liu ◽  
...  

2015 ◽  
Vol 197 (18) ◽  
pp. 2908-2919 ◽  
Author(s):  
Anthony O. Gaca ◽  
Pavel Kudrin ◽  
Cristina Colomer-Winter ◽  
Jelena Beljantseva ◽  
Kuanqing Liu ◽  
...  

ABSTRACTThe bacterial stringent response (SR) is a conserved stress tolerance mechanism that orchestrates physiological alterations to enhance cell survival. This response is mediated by the intracellular accumulation of the alarmones pppGpp and ppGpp, collectively called (p)ppGpp. InEnterococcus faecalis, (p)ppGpp metabolism is carried out by the bifunctional synthetase/hydrolaseE. faecalisRel (RelEf) and the small alarmone synthetase (SAS) RelQEf. Although Rel is the main enzyme responsible for SR activation inFirmicutes, there is emerging evidence that SASs can make important contributions to bacterial homeostasis. Here, we showed that RelQEfsynthesizes ppGpp more efficiently than pppGpp without the need for ribosomes, tRNA, or mRNA. In addition to (p)ppGpp synthesis from GDP and GTP, RelQEfalso efficiently utilized GMP to form GMP 3′-diphosphate (pGpp). Based on this observation, we sought to determine if pGpp exerts regulatory effects on cellular processes affected by (p)ppGpp. We found that pGpp, like (p)ppGpp, strongly inhibits the activity ofE. faecalisenzymes involved in GTP biosynthesis and, to a lesser extent, transcription ofrrnBbyEscherichia coliRNA polymerase. Activation ofE. coliRelA synthetase activity was observed in the presence of both pGpp and ppGpp, while RelQEfwas activated only by ppGpp. Furthermore, enzymatic activity of RelQEfis insensitive to relacin, a (p)ppGpp analog developed as an inhibitor of “long” RelA/SpoT homolog (RSH) enzymes. We conclude that pGpp can likely function as a bacterial alarmone with target-specific regulatory effects that are similar to what has been observed for (p)ppGpp.IMPORTANCEAccumulation of the nucleotide second messengers (p)ppGpp in bacteria is an important signal regulating genetic and physiological networks contributing to stress tolerance, antibiotic persistence, and virulence. Understanding the function and regulation of the enzymes involved in (p)ppGpp turnover is therefore critical for designing strategies to eliminate the protective effects of this molecule. While characterizing the (p)ppGpp synthetase RelQ ofEnterococcus faecalis(RelQEf), we found that, in addition to (p)ppGpp, RelQEfis an efficient producer of pGpp (GMP 3′-diphosphate).In vitroanalysis revealed that pGpp exerts complex, target-specific effects on processes known to be modulated by (p)ppGpp. These findings provide a new regulatory feature of RelQEfand suggest that pGpp may represent a new member of the (pp)pGpp family of alarmones.


2016 ◽  
Vol 198 (7) ◽  
pp. 1087-1100 ◽  
Author(s):  
Gursonika Binepal ◽  
Kamal Gill ◽  
Paula Crowley ◽  
Martha Cordova ◽  
L. Jeannine Brady ◽  
...  

ABSTRACTPotassium (K+) is the most abundant cation in the fluids of dental biofilm. The biochemical and biophysical functions of K+and a variety of K+transport systems have been studied for most pathogenic bacteria but not for oral pathogens. In this study, we establish the modes of K+acquisition inStreptococcus mutansand the importance of K+homeostasis for its virulence attributes. TheS. mutansgenome harbors four putative K+transport systems that included two Trk-like transporters (designated Trk1 and Trk2), one glutamate/K+cotransporter (GlnQHMP), and a channel-like K+transport system (Kch). Mutants lacking Trk2 had significantly impaired growth, acidogenicity, aciduricity, and biofilm formation. [K+] less than 5 mM eliminated biofilm formation inS. mutans. The functionality of the Trk2 system was confirmed by complementing anEscherichia coliTK2420 mutant strain, which resulted in significant K+accumulation, improved growth, and survival under stress. Taken together, these results suggest that Trk2 is the main facet of the K+-dependent cellular response ofS. mutansto environment stresses.IMPORTANCEBiofilm formation and stress tolerance are important virulence properties of caries-causingStreptococcus mutans. To limit these properties of this bacterium, it is imperative to understand its survival mechanisms. Potassium is the most abundant cation in dental plaque, the natural environment ofS. mutans. K+is known to function in stress tolerance, and bacteria have specialized mechanisms for its uptake. However, there are no reports to identify or characterize specific K+transporters inS. mutans. We identified the most important system for K+homeostasis and its role in the biofilm formation, stress tolerance, and growth. We also show the requirement of environmental K+for the activity of biofilm-forming enzymes, which explains why such high levels of K+would favor biofilm formation.


Author(s):  
Andrea Lauková ◽  
Anna Kandričáková ◽  
Eva Bino

This study investigated eight types of Slovak dry fermented meat products (salami and sausages) that are available on the market and were produced by three different producers in different regions of Slovakia. The total counts of enterococci in these products ranged from 2.0 up to 6.0 cfu/g (log10). Three species were identified among the 15 selected enterococcal strains; Enterococcus faecium (8 strains), Enterococcus faecalis (3) and Enterococcus hirae (4). They were hemolysis-negative (γ-hemolysis) with a biofilm-forming ability, which was evaluated as low-grade biofilm formation, susceptible to conventional antibiotics and mainly susceptible to lantibiotic bacteriocins, namely, gallidermin and nisin; they even showed a higher susceptibility to gallidermin than to nisin. They were also susceptible to enterocin–durancin, but most strains showed resistance to enterocin A/P. This study indicated that bacteriocins can play a key role in preventing and/or protecting from undesirable bacterial multiplication or contamination in the food industry and that they have great potential for further experimental applications.


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