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Huang X, Laird CG, Riley PP, Wen ZT. Impacts of a DUF2207 Family Protein on Streptococcus mutans Stress Tolerance Responses and Biofilm Formation. Microorganisms 2023; 11:1982. [PMID: 37630542 PMCID: PMC10457818 DOI: 10.3390/microorganisms11081982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/30/2023] [Accepted: 07/31/2023] [Indexed: 08/27/2023] Open
Abstract
Locus SMU.243 in Streptococcus mutans was annotated as a member of the DUF2207 family proteins highly conserved in all bacteria but with unknown function. To investigate its role in S. mutans physiology, a SMU.243-deficient mutant was constructed using allelic exchange mutagenesis, and the impacts of SMU.243 deletion on bacterial growth, stress tolerance response, and biofilm formation were analyzed. Compared to the wild-type UA159, S. mutans lacking SMU.243 displayed a reduced growth rate and a reduced overnight culture density (p < 0.01) when grown at low pH and in the presence of methyl viologen. Relative to the parent strain, the deficient mutant also had a reduced survival rate following incubation in a buffer of pH 2.8 (p < 0.01) and in a buffer containing hydrogen peroxide at 58 mM after 60 min (p < 0.001) and had a reduced capacity in biofilm formation especially in the presence of sucrose (p < 0.01). To study any ensuing functional/phenotypical links between SMU.243 and uppP, which is located immediately downstream of SMU.243 and encodes an undecaprenyl pyrophosphate phosphatase involved in recycling of carrier lipid undecaprenyl phosphate, a uppP deficient mutant was generated using allelic exchange mutagenesis. Unlike the SMU.243 mutant, deletion of uppP affected cell envelope biogenesis and caused major increases in susceptibility to bacitracin. In addition, two variant morphological mutants, one forming rough colonies and the other forming mucoid, smooth colonies, also emerged following the deletion of uppP. The results suggest that the SMU.243-encoded protein of the DUF2207 family in S. mutans plays an important role in stress tolerance response and biofilm formation, but unlike the downstream uppP, does not seem to be involved in cell envelope biogenesis, although the exact roles in S. mutans' physiology awaits further investigation.
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Affiliation(s)
- Xiaochang Huang
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; (X.H.); (P.P.R.)
| | - Camile G. Laird
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; (X.H.); (P.P.R.)
| | - Paul P. Riley
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; (X.H.); (P.P.R.)
| | - Zezhang Tom Wen
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; (X.H.); (P.P.R.)
- Department of Microbiology, Immunology and Parasitology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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2
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Yun J, Zabed HM, Zhang Y, Zhang G, Zhao M, Qi X. Improving tolerance and 1,3-propanediol production of Clostridium butyricum using physical mutagenesis, adaptive evolution and genome shuffling. BIORESOURCE TECHNOLOGY 2022; 363:127967. [PMID: 36113815 DOI: 10.1016/j.biortech.2022.127967] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 06/15/2023]
Abstract
Bioconversion efficiency of glycerol to 1,3-propanediol (1,3-PD) by Clostridium butyricum is bottlenecked by its low tolerance to various stressors, especially glycerol as the substrate, 1,3-PD as the end product, and butyric acid as a by-product, which eventually decreases 1,3-PD yield. This study aimed at improving the tolerance and 1,3-PD production capability of C. butyricum using random mutagenesis and evolutionary techniques. Mutagenesis of wild strain by atmospheric room temperature plasma (ARTP) provided the first population with maximum tolerance to 160 g/L glycerol, while microbial microdroplet culture system (MMC)-mediated adaptive laboratory evolution (ALE) generated the second population with tolerance to 100 g/L 1,3-PD. Subsequently, genome shuffling of both populations yielded a final strain, GJH-418, which generated 60.12 g/L1,3-PD with a productivity of 1.72 g/L/h. The transcript analysis of the mutant and wild strains revealed the possible involvement of 8 genes in high tolerance and high 1,3-PD production through either up- or down-regulation.
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Affiliation(s)
- Junhua Yun
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China
| | - Hossain M Zabed
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China
| | - Yufei Zhang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China
| | - Guoyan Zhang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China
| | - Mei Zhao
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China
| | - Xianghui Qi
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China.
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3
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Naka S, Matsuoka D, Goto K, Misaki T, Nagasawa Y, Ito S, Nomura R, Nakano K, Matsumoto-Nakano M. Cnm of Streptococcus mutans is important for cell surface structure and membrane permeability. Front Cell Infect Microbiol 2022; 12:994014. [PMID: 36176579 PMCID: PMC9513430 DOI: 10.3389/fcimb.2022.994014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/18/2022] [Indexed: 11/18/2022] Open
Abstract
Streptococcus mutans, a Gram-positive facultative anaerobic bacterium, is a major pathogen of dental caries. The protein Cnm of S. mutans is involved in collagen binding, but its other biological functions are unknown. In this study, a Cnm-deficient isogenic mutant and a complementation strain were generated from a Cnm-positive S. mutans strain to help determine the properties of Cnm. Initially, comparison of the cell surface structure was performed by electron microscopy, which demonstrated that Cnm appears to be localized on the cell surface and associated with a protruding cell surface structure. Deep RNA sequencing of the strains revealed that the defect in Cnm caused upregulated expression of many genes related to ABC transporters and cell-surface proteins, while a few genes were downregulated. The amount of biofilm formed by the Cnm-defective strain increased compared with the parental and complemented strains, but the biofilm structure was thinner because of elevated expression of genes encoding glucan synthesis enzymes, leading to increased production of extracellular polysaccharides. Particular antibiotics, including bacitracin and chloramphenicol, had a lower minimum inhibitory concentration for the Cnm-defective strain than particular antibiotics, including bacitracin and chloramphenicol, compared with the parental and complemented strains. Our results suggest that S. mutans Cnm is located on the cell surface, gives rise to the observed protruding cell surface, and is associated with several biological properties related to membrane permeability.
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Affiliation(s)
- Shuhei Naka
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Daiki Matsuoka
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Kana Goto
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Taro Misaki
- Division of Nephrology, Seirei Hamamatsu General Hospital, Hamamatsu, Japan
- Department of Nursing, Faculty of Nursing, Seirei Christopher University, Hamamatsu, Japan
| | - Yasuyuki Nagasawa
- Department of General Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Seigo Ito
- Department of Internal Medicine, Japan Self-Defense Iruma Hospital, Iruma, Japan
| | - Ryota Nomura
- Department of Pediatric Dentistry, Division of Oral infection and Disease Control, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Division of Oral infection and Disease Control, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Michiyo Matsumoto-Nakano
- Department of Pediatric Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- *Correspondence: Michiyo Matsumoto-Nakano,
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Hsu CC, Hsu RB, Oon XH, Chen YT, Chen JW, Hsu CH, Kuo YM, Shih YH, Chia JS, Jung CJ. Streptococcus mutans PrsA mediates AtlA secretion contributing to extracellular DNA release and biofilm formation in the pathogenesis of infective endocarditis. Virulence 2022; 13:1379-1392. [PMID: 35876630 PMCID: PMC9377233 DOI: 10.1080/21505594.2022.2105351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The role of secretion chaperone-regulated virulence proteins in the pathogenesis of infective endocarditis (IE) induced by viridans streptococci such as Streptococcus mutans is unclear. In this study, we investigated the contribution of the foldase protein PrsA, a putative parvulin-type peptidyl-prolyl isomerase, to the pathogenesis of S. mutans-induced IE. We found that a prsA-deficient strain had reduced virulence in terms of formation of vegetation on damaged heart valves, as well as reduced autolysis activity, eDNA release and biofilm formation capacity. The secretion and surface exposure of AtlA in vitro was reduced in the prsA-deficient mutant strain, and complementation of recombinant AtlA in the culture medium restored a wild type biofilm phenotype of the prsA-deficient mutant strain. This result suggests that secretion and surface localization of AtlA is regulated by PrsA during biofilm formation. Together, these results demonstrate that S. mutans PrsA could regulate AtlA-mediated eDNA release to contribute to biofilm formation in the pathogenesis of IE.
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Affiliation(s)
- Chih-Chieh Hsu
- Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Oral Biology, School of Dentistry, National Taiwan University, Taipei, Taiwan
| | - Ron-Bin Hsu
- Department of Surgery, Division of Cardiovascular Surgery, National Taiwan University Hospital , College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Xoong-Harng Oon
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan.,Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Ya-Tang Chen
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan
| | - Jeng-Wei Chen
- Department of Surgery, Division of Cardiovascular Surgery, National Taiwan University Hospital , College of Medicine, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Che-Hao Hsu
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan
| | - Yu-Min Kuo
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Division of Allergy, Immunology, and Rheumatology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Yi-Hsien Shih
- Department of Dermatology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan.,Department of Dermatology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jean-San Chia
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan.,Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chiau-Jing Jung
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan.,Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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Kruppa O, Czermak P. Screening for Biofilm-Stimulating Factors in the Freshwater Planctomycete Planctopirus limnophila to Improve Sessile Growth in a Chemically Defined Medium. Microorganisms 2022; 10:microorganisms10040801. [PMID: 35456851 PMCID: PMC9028447 DOI: 10.3390/microorganisms10040801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/31/2022] [Accepted: 04/10/2022] [Indexed: 12/26/2022] Open
Abstract
Planctomycetes such as Planctopirus limnophila offer a promising source of bioactive molecules, particularly when they switch from planktonic to sessile growth, but little is known about the corresponding biosynthetic gene clusters and how they are activated. We therefore screened for factors that promote sessile growth and biofilm formation to enable the cultivation of P. limnophila in a fixed-bed reactor. We carried out screening in microtiter plates focusing on biofilm formation and changes in optical density in response to various C:N ratios, metal ions, and oxidative stress. We used MTT assays and crystal violet staining to quantify biofilm formation. Positive factors were then validated in a fixed-bed bioreactor. The initial screen showed that D1ASO medium supplemented with NH4Cl to achieve a C:N ratio of 5.7:1, as well as 50 µM FeSO4 or CuSO4, increased the biofilm formation relative to the control medium. Exposure to H2O2 did not affect cell viability but stimulated biofilm formation. However, the same results were not replicated in the fixed-bed bioreactor, probably reflecting conditions that are unique to this environment such as the controlled pH and more vigorous aeration. Although we were able to cultivate P. limnophila in a fixed-bed bioreactor using a chemically defined medium, the factors that stimulate biofilm formation and inhibit planktonic growth were only identified in microtiter plates and further evaluation is required to establish optimal growth conditions in the bioreactor system.
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Affiliation(s)
- Oscar Kruppa
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, 35390 Giessen, Germany;
| | - Peter Czermak
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, 35390 Giessen, Germany;
- Faculty of Biology and Chemistry, Justus-Liebig University of Giessen, 35390 Giessen, Germany
- Correspondence:
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Songsantiphap C, Vanichanan J, Chatsuwan T, Asawanonda P, Boontaveeyuwat E. Methylene Blue-Mediated Antimicrobial Photodynamic Therapy Against Clinical Isolates of Extensively Drug Resistant Gram-Negative Bacteria Causing Nosocomial Infections in Thailand, An In Vitro Study. Front Cell Infect Microbiol 2022; 12:929242. [PMID: 35846758 PMCID: PMC9283779 DOI: 10.3389/fcimb.2022.929242] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 05/31/2022] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND/PURPOSE Some multidrug-resistant gram-negative bacteria as a global threat have been recently prioritized for research and development of new treatments. We studied the efficacy of methylene blue-mediated antimicrobial photodynamic therapy (MB-aPDT) for the reduction of extensively drug-resistant Acinetobacter baumannii (XDR-AB) and Pseudomonas aeruginosa (XDR-PS) and multidrug-resistant Klebsiella pneumoniae (MDR-KP) isolated in a university hospital setting in Thailand. METHOD Two isolates of each selected bacterium were collected, XDR-AB1 and AB2, XDR- PS1 and PS2, and MDR-KP1 and KP2. Three triplicate experiments using various MB concentrations alone, various red light fluences alone, as well as the selected non-toxic doses of MB and fluences of red light combined as MB-aPDT were applied on each selected isolate. The colonies were counted [colony forming units (CFU)/ml]. Estimation of the lethal treatment dose defined as reduction of > 2 log10 in CFU/ml compared with untreated bacteria. RESULT There were generally negligible changes in the viable counts of the bacterial suspensions treated with all the MB concentrations (p > 0.05). In the second experiment with the only red light treatments, at fluences higher than 2 J/cm, reduction trend in viable counts across all the isolates was observed. Only for MDR-KP1, however, the lethal dose was achieved with the highest fluence of red light (80 J/cm). With the concentration of MB, 50 and 150 mg/L in the third experiment (MB-aPDT), the greater bacterial reduction was observed in all clinical isolates leading to their lethal viable cell reduction when escalating the light fluence to 80 J/cm. CONCLUSIONS MB-aPDT evidently killed the selected XDR and MDR-gram negative bacteria. In highly drug-resistant crisis era, MB-aPDT could be a promising option, particularly for local infections and infection complicating chronic wounds.
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Affiliation(s)
- Chankiat Songsantiphap
- Photodermatology Unit, Division of Dermatology, Department of Medicine, King Chulalongkorn Memorial Hospital and Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Jakapat Vanichanan
- Division of Infectious Diseases, Department of Medicine, King Chulalongkorn Memorial Hospital and Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Tanittha Chatsuwan
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Antimicrobial Resistance and Stewardship Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Pravit Asawanonda
- Photodermatology Unit, Division of Dermatology, Department of Medicine, King Chulalongkorn Memorial Hospital and Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Einapak Boontaveeyuwat
- Photodermatology Unit, Division of Dermatology, Department of Medicine, King Chulalongkorn Memorial Hospital and Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- *Correspondence: Einapak Boontaveeyuwat,
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Sharma D, Aswal M, Ahmad N, Kumar M, Khan AU. Proteomic analysis of the colistin-resistant E. coli clinical isolate: Explorations of the resistome. Protein Pept Lett 2021; 29:184-198. [PMID: 34844531 DOI: 10.2174/0929866528666211129095001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/12/2021] [Accepted: 10/20/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Antimicrobial resistance is a worldwide problem after the emergence of colistin resistance since it was the last option left to treat carbapenemase-resistant bacterial infections. The mcr gene and its variants are one of the causes for colistin resistance. Besides mcr genes, some other intrinsic genes are also involved in colistin resistance but still need to be explored. OBJECTIVE The aim of this study was to investigate differential proteins expression of colistin-resistant E. coli clinical isolate and to understand their interactive partners as future drug targets. METHODS In this study, we have employed the whole proteome analysis through LC-MS/MS. The advance proteomics tools were used to find differentially expressed proteins in the colistin-resistant Escherichia coli clinical isolate compared to susceptible isolate. Gene ontology and STRING were used for functional annotation and protein-protein interaction networks, respectively. RESULTS LC-MS/MS analysis showed overexpression of 47 proteins and underexpression of 74 proteins in colistin-resistant E. coli. These proteins belong to DNA replication, transcription and translational process; defense and stress related proteins; proteins of phosphoenol pyruvate phosphotransferase system (PTS) and sugar metabolism. Functional annotation and protein-protein interaction showed translational and cellular metabolic process, sugar metabolism and metabolite interconversion. CONCLUSION We conclude that these protein targets and their pathways might be used to develop novel therapeutics against colistin-resistant infections. These proteins could unveil the mechanism of colistin resistance.
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Affiliation(s)
- Divakar Sharma
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh. India
| | - Manisha Aswal
- Department of Biophysics, University of Delhi South Campus. India
| | - Nayeem Ahmad
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh. India
| | - Manish Kumar
- Department of Biophysics, University of Delhi South Campus. India
| | - Asad U Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh. India
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8
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Wang Y, Hoffmann JP, Baker SM, Bentrup KHZ, Wimley WC, Fuselier JA, Bitoun JP, Morici LA. Inhibition of Streptococcus mutans biofilms with bacterial-derived outer membrane vesicles. BMC Microbiol 2021; 21:234. [PMID: 34429066 PMCID: PMC8386047 DOI: 10.1186/s12866-021-02296-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/13/2021] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Biofilms are microbial communities surrounded by a self-produced extracellular matrix which protects them from environmental stress. Bacteria within biofilms are 10- to 1000-fold more resistant to antibiotics, making it challenging but imperative to develop new therapeutics that can disperse biofilms and eradicate infection. Gram-negative bacteria produce outer membrane vesicles (OMV) that play critical roles in communication, genetic exchange, cargo delivery, and pathogenesis. We have previously shown that OMVs derived from Burkholderia thailandensis inhibit the growth of drug-sensitive and drug-resistant bacteria and fungi. RESULTS Here, we examine the antibiofilm activity of Burkholderia thailandensis OMVs against the oral biofilm-forming pathogen Streptococcus mutans. We demonstrate that OMV treatment reduces biofilm biomass, biofilm integrity, and bacterial cell viability. Both heat-labile and heat-stable components, including 4-hydroxy-3-methyl-2-(2-non-enyl)-quinoline and long-chain rhamnolipid, contribute to the antibiofilm activity of OMVs. When OMVs are co-administered with gentamicin, the efficacy of the antibiotic against S. mutans biofilms is enhanced. CONCLUSION These studies indicate that bacterial-derived OMVs are highly effective biological nanoparticles that can inhibit and potentially eradicate biofilms.
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Affiliation(s)
- Yihui Wang
- grid.265219.b0000 0001 2217 8588Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Ave., SL-38, LA 70112-2699 New Orleans, USA
| | - Joseph P. Hoffmann
- grid.265219.b0000 0001 2217 8588Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Ave., SL-38, LA 70112-2699 New Orleans, USA
| | - Sarah M. Baker
- grid.265219.b0000 0001 2217 8588Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Ave., SL-38, LA 70112-2699 New Orleans, USA
| | - Kerstin Höner zu Bentrup
- grid.265219.b0000 0001 2217 8588Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Ave., SL-38, LA 70112-2699 New Orleans, USA
| | - William C. Wimley
- grid.265219.b0000 0001 2217 8588Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA USA
| | - Joseph A. Fuselier
- grid.265219.b0000 0001 2217 8588Department of Medicine, Tulane University School of Medicine, New Orleans, LA USA
| | - Jacob P. Bitoun
- grid.265219.b0000 0001 2217 8588Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Ave., SL-38, LA 70112-2699 New Orleans, USA
| | - Lisa A. Morici
- grid.265219.b0000 0001 2217 8588Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Ave., SL-38, LA 70112-2699 New Orleans, USA
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Staphylococcus aureus Trigger Factor Is Involved in Biofilm Formation and Cooperates with the Chaperone PpiB. J Bacteriol 2021; 203:JB.00681-20. [PMID: 33468596 DOI: 10.1128/jb.00681-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/07/2021] [Indexed: 12/18/2022] Open
Abstract
Peptidyl-prolyl cis/trans isomerases (PPIases) are enzymes that assist in protein folding around proline-peptide bonds, and they often possess chaperone activity. Staphylococcus aureus encodes three PPIases, i.e., PrsA, PpiB, and trigger factor (TF). Previous work by our group demonstrated a role for both PrsA and PpiB in S. aureus; however, TF remains largely unstudied. Here, we identify a role for TF in S. aureus biofilm formation and demonstrate cooperation between TF and the cytoplasmic PPIase PpiB. Mutation of the tig gene (encoding TF) led to reduced biofilm development in vitro but no significant attenuation of virulence in a mouse model of infection. To investigate whether TF possesses chaperone activity, we analyzed the ability of a tig mutant to survive acid and base stress. While there was no significant decrease for a tig mutant, a ppiB tig double mutant exhibited significant decreases in cell viability after acid and base challenges. We then demonstrated that a ppiB tig double mutant had exacerbated phenotypes in vitro and in vivo, compared to either single mutant. Finally, in vivo immunoprecipitation of epitope-tagged PpiB revealed that PpiB interacted with 4 times the number of proteins when TF was absent from the cell, suggesting that it may be compensating for the loss of TF. Interestingly, the only proteins found to interact with TF were TF itself, fibronectin-binding protein B (FnBPB), and the chaperone protein ClpB. Collectively, these results support the first phenotype for S. aureus TF and demonstrate a greater network of cooperation between chaperone proteins in Staphylococcus aureus IMPORTANCE S. aureus encodes a large number of virulence factors that aid the bacterium in survival and pathogenesis. These virulence factors have a wide variety of functions; however, they must all be properly secreted in order to be functional. Bacterial chaperone proteins often assist in secretion by trafficking proteins to secretion machinery or assisting in proper protein folding. Here, we report that the S. aureus chaperone TF contributes to biofilm formation and cooperates with the chaperone PpiB to regulate S. aureus virulence processes. These data highlight the first known role for TF in S. aureus and suggest that S. aureus chaperone proteins may be involved in a greater regulatory network in the cell.
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10
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Kim K, Kim JN, Lim BS, Ahn SJ. Urethane Dimethacrylate Influences the Cariogenic Properties of Streptococcus Mutans. MATERIALS 2021; 14:ma14041015. [PMID: 33669956 PMCID: PMC7924865 DOI: 10.3390/ma14041015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 01/09/2023]
Abstract
Concerns regarding unbound monomers in dental composites have increased with the increased usage of these materials. This study assessed the biological effects of urethane dimethacrylate (UDMA), a common monomer component of dental composite resins, on the cariogenic properties of Streptococcus mutans. Changes in the growth rate, biofilm formation, interaction with saliva, surface hydrophobicity, adhesion, glucan synthesis, sugar transport, glycolytic profiles, and oxidative- and acid-stress tolerances of S. mutans were evaluated after growing the cells in the presence and absence of UDMA. The results indicated that UDMA promotes the adhesion of S. mutans to the underlying surfaces and extracellular polysaccharide synthesis, leading to enhanced biofilm formation. Furthermore, UDMA reduced the acid tolerance of S. mutans, but enhanced its tolerance to oxidative stress, thus favoring the early stage of biofilm development. UDMA did not significantly affect the viability or planktonic growth of cells, but diminished the ability of S. mutans to metabolize carbohydrates and thus maintain the level of intracellular polysaccharides, although the tendency for sugar transport increased. Notably, UDMA did not significantly alter the interactions of bacterial cells with saliva. This study suggests that UDMA may potentially contribute to the development of secondary caries around UDMA-containing dental materials by prompting biofilm formation, enhancing oxidative tolerance, and modulating carbon flow.
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Affiliation(s)
- Kyungsun Kim
- Dental Research Institute and Department of Microbiology and Immunology, School of Dentistry, Seoul National University, Seoul 03080, Korea;
| | - Jeong Nam Kim
- Department of Microbiology, College of Natural Sciences, Pusan National University, Busan 46241, Korea;
| | - Bum-Soon Lim
- Dental Research Institute and Department of Dental Biomaterial Science, School of Dentistry, Seoul National University, Seoul 03080, Korea;
| | - Sug-Joon Ahn
- Dental Research Institute and Department of Orthodontics, School of Dentistry, Seoul National University, Seoul 03080, Korea
- Correspondence: ; Tel.: +82-2-2072-2671
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Deciphering Streptococcal Biofilms. Microorganisms 2020; 8:microorganisms8111835. [PMID: 33233415 PMCID: PMC7700319 DOI: 10.3390/microorganisms8111835] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/10/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Streptococci are a diverse group of bacteria, which are mostly commensals but also cause a considerable proportion of life-threatening infections. They colonize many different host niches such as the oral cavity, the respiratory, gastrointestinal, and urogenital tract. While these host compartments impose different environmental conditions, many streptococci form biofilms on mucosal membranes facilitating their prolonged survival. In response to environmental conditions or stimuli, bacteria experience profound physiologic and metabolic changes during biofilm formation. While investigating bacterial cells under planktonic and biofilm conditions, various genes have been identified that are important for the initial step of biofilm formation. Expression patterns of these genes during the transition from planktonic to biofilm growth suggest a highly regulated and complex process. Biofilms as a bacterial survival strategy allow evasion of host immunity and protection against antibiotic therapy. However, the exact mechanisms by which biofilm-associated bacteria cause disease are poorly understood. Therefore, advanced molecular techniques are employed to identify gene(s) or protein(s) as targets for the development of antibiofilm therapeutic approaches. We review our current understanding of biofilm formation in different streptococci and how biofilm production may alter virulence-associated characteristics of these species. In addition, we have summarized the role of surface proteins especially pili proteins in biofilm formation. This review will provide an overview of strategies which may be exploited for developing novel approaches against biofilm-related streptococcal infections.
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12
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Hanachi M, Kiran A, Cornick J, Harigua-Souiai E, Everett D, Benkahla A, Souiai O. Genomic Characteristics of Invasive Streptococcus pneumoniae Serotype 1 in New Caledonia Prior to the Introduction of PCV13. Bioinform Biol Insights 2020; 14:1177932220962106. [PMID: 33088176 PMCID: PMC7545519 DOI: 10.1177/1177932220962106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 08/31/2020] [Indexed: 12/17/2022] Open
Abstract
Streptococcus pneumoniae serotype 1 is a common cause of global invasive pneumococcal disease. In New Caledonia, serotype 1 is the most prevalent serotype and led to two major outbreaks reported in the 2000s. The pneumococcal conjugate vaccine 13 (PCV13) was introduced into the vaccination routine, intending to prevent the expansion of serotype 1 in New Caledonia. Aiming to provide a baseline for monitoring the post-PCV13 changes, we performed a whole-genome sequence analysis on 67 serotype 1 isolates collected prior to the PCV13 introduction. To highlight the S. pneumoniae serotype 1 population structure, we performed a multilocus sequence typing (MLST) analysis revealing that NC serotype 1 consisted of 2 sequence types: ST3717 and the highly dominant ST306. Both sequence types harbored the same resistance genes to beta-lactams, macrolide, streptogramin B, fluoroquinolone, and lincosamide antibiotics. We have also identified 36 virulence genes that were ubiquitous to all the isolates. Among these virulence genes, the pneumolysin sequence presented an allelic profile associated with disease outbreaks and reduced hemolytic activity. Moreover, recombination hotspots were identified in 4 virulence genes and more notably in the cps locus (cps2L), potentially leading to capsular switching, a major mechanism of the emergence of nonvaccine types. In summary, this study represents the first overview of the genomic characteristics of S. pneumoniae serotype 1 in New Caledonia prior to the introduction of PCV13. This preliminary description represents a baseline to assess the impact of PCV13 on serotype 1 population structure and genomic diversity.
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Affiliation(s)
- Mariem Hanachi
- Laboratory of Bioinformatics, Biomathematics and Biostatistics-LR16IPT09, Institut Pasteur de Tunis, University of Tunis El Manar (UTM), Tunis, Tunisia.,Faculty of Science of Bizerte, University of Carthage, Jarzouna, Tunisia
| | - Anmol Kiran
- Queens Research Institute, University of Edinburgh, Edinburgh, UK.,Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Jennifer Cornick
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Departement of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Emna Harigua-Souiai
- Laboratory of Molecular Epidemiology and Experimental Pathology-LR16IPT04, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Dean Everett
- Queens Research Institute, University of Edinburgh, Edinburgh, UK.,Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Alia Benkahla
- Laboratory of Bioinformatics, Biomathematics and Biostatistics-LR16IPT09, Institut Pasteur de Tunis, University of Tunis El Manar (UTM), Tunis, Tunisia
| | - Oussama Souiai
- Laboratory of Bioinformatics, Biomathematics and Biostatistics-LR16IPT09, Institut Pasteur de Tunis, University of Tunis El Manar (UTM), Tunis, Tunisia.,Institut Supérieur des Technologies Médicales de Tunis, Université de Tunis El Manar, Tunis, Tunisia
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13
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Li Z, Zhang C, Li C, Zhou J, Xu X, Peng X, Zhou X. S-glutathionylation proteome profiling reveals a crucial role of a thioredoxin-like protein in interspecies competition and cariogenecity of Streptococcus mutans. PLoS Pathog 2020; 16:e1008774. [PMID: 32716974 PMCID: PMC7410335 DOI: 10.1371/journal.ppat.1008774] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 08/06/2020] [Accepted: 07/01/2020] [Indexed: 02/05/2023] Open
Abstract
S-glutathionylation is an important post-translational modification (PTM) process that targets protein cysteine thiols by the addition of glutathione (GSH). This modification can prevent proteolysis caused by the excessive oxidation of protein cysteine residues under oxidative or nitrosative stress conditions. Recent studies have suggested that protein S-glutathionylation plays an essential role in the control of cell-signaling pathways by affecting the protein function in bacteria and even humans. In this study, we investigated the effects of S-glutathionylation on physiological regulation within Streptococcus mutans, the primary etiological agent of human dental caries. To determine the S-glutathionylated proteins in bacteria, the Cys reactive isobaric reagent iodoacetyl Tandem Mass Tag (iodoTMT) was used to label the S-glutathionylated Cys site, and an anti-TMT antibody-conjugated resin was used to enrich the modified peptides. Proteome profiling identified a total of 357 glutathionylated cysteine residues on 239 proteins. Functional enrichment analysis indicated that these S-glutathionylated proteins were involved in diverse important biological processes, such as pyruvate metabolism and glycolysis. Furthermore, we studied a thioredoxin-like protein (Tlp) to explore the effect of S-glutathionylation on interspecies competition between oral streptococcal biofilms. Through site mutagenesis, it was proved that glutathionylation on Cys41 residue of Tlp is crucial to protect S. mutans from oxidative stress and compete with S. sanguinis and S. gordonii. An addition rat caries model showed that the loss of S-glutathionylation attenuated the cariogenicity of S. mutans. Taken together, our study provides an insight into the S-glutathionylation of bacterial proteins and the regulation of oxidative stress resistance and interspecies competition.
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Affiliation(s)
- Zhengyi Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chenzi Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Cheng Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jiajia Zhou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xin Xu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xian Peng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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WU S, LIU Y, ZHANG H, LEI L. Nano-graphene oxide with antisense vicR RNA reduced exopolysaccharide synthesis and biofilm aggregation for Streptococcus mutans . Dent Mater J 2020; 39:278-286. [PMID: 31827056 DOI: 10.4012/dmj.2019-039] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Shizhou WU
- Department of Orthopedics, West China Hospital, Sichuan University
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University
| | - Yunjie LIU
- West China School of Public Health, Sichuan University
| | - Hui ZHANG
- Department of Orthopedics, West China Hospital, Sichuan University
| | - Lei LEI
- State Key Laboratory of Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University
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15
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Hendiani S, Rybtke ML, Tolker-Nielsen T, Kashef N. Sub-lethal antimicrobial photodynamic inactivation affects Pseudomonas aeruginosa PAO1 quorum sensing and cyclic di-GMP regulatory systems. Photodiagnosis Photodyn Ther 2019; 27:467-473. [PMID: 31362113 DOI: 10.1016/j.pdpdt.2019.07.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/02/2019] [Accepted: 07/26/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Antimicrobial photodynamic inactivation (APDI) is a new therapeutic modality which needs more precision during application due to the possibility of exposure of bacteria to sub-lethal doses (sAPDI). In this study, we aimed to evaluate the effect of sAPDI on Pseudomonas aeruginosa quorum sensing (QS) and c-di-GMP signaling which are important virulence factor regulatory systems. METHODS Biofilm formation, pyoverdine, pyocyanin and protease production of P. aeruginosa was evaluated before and after a single sAPDI treatment with 0.8 mM methylene blue (MB) plus 1, 2, and 5-min irradiation with red laser light. Fluorescent lasB, rhlA, pqsA, and cdrA reporters of P. aeruginosa PAO1 and P. aeruginosa ΔmexAB-oprM were treated individually with sAPDI and the regulatory signals were detected. The gene expressions were also assessed after sAPDI using quantitative real-time PCR analysis. RESULTS Morphological observations and molecular assessments indicated that sAPDI with 0.8 mM MB along with 2- and 5-min irradiation led to an increase in the expression of the Las QS system and c-di-GMP signaling, while 1 min irradiation revealed dissimilar results (increase in lasB expression and decrease in c-di-GMP levels). Expression of rhlA and pqsA did not change in response to sAPDI. Further, a severe lethal effect of sAPDI was observed in P. aeruginosa ΔmexAB-oprM as compared with the wild type strain, whilst there was no difference in QS and c-di-GMP levels as detected by reporters between treated and untreated samples. CONCLUSION The results suggest that sAPDI affects QS and c-di-GMP signaling inP. aeruginosa in a time-dependent manner.
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Affiliation(s)
- Saghar Hendiani
- Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
| | - Morten Levin Rybtke
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Nasim Kashef
- Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
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16
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Shafiei R, Leprince P, Sombolestani AS, Thonart P, Delvigne F. Effect of Sequential Acclimation to Various Carbon Sources on the Proteome of Acetobacter senegalensis LMG 23690 T and Its Tolerance to Downstream Process Stresses. Front Microbiol 2019; 10:608. [PMID: 30984138 PMCID: PMC6448019 DOI: 10.3389/fmicb.2019.00608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 03/11/2019] [Indexed: 11/23/2022] Open
Abstract
Acetic acid bacteria are very vulnerable to environmental changes; hence, they should get acclimated to different kinds of stresses when they undergo downstream processing. In the present study, Acetobacter senegalensis LMG 23690T, a thermo-tolerant strain, was acclimated sequentially to different carbon sources including glucose (condition Glc), a mixture of glucose and ethanol (condition EtOH) and a mixture of glucose and acetic acid (condition GlcAA). Then, the effects of acclimation on the cell proteome profiles and some phenotypic characteristics such as growth in culture medium containing ethanol, and tolerance to freeze-drying process were evaluated. Based on the obtained results, despite the cells acclimated to Glc or EtOH conditions, 86% of acclimated cells to GlcAA condition were culturable and resumed growth with a short lag phase in a culture medium containing ethanol and acetic acid. Interestingly, if A. senegalensis LMG 23690T had been acclimated to condition GlcAA, 92% of cells exhibited active cellular dehydrogenases, and 59% of cells were culturable after freeze-drying process. Proteome profiles comparison by 2D-DiGE and MS analysis, revealed distinct physiological status between cells exposed to different acclimation treatments, possibly explaining the resulting diversity in phenotypic characteristics. Results of proteome analysis by 2D-DiGE also showed similarities between the differentially expressed proteins of acclimated cells to EtOH condition and the proteome of acclimated cells to GlcAA condition. Most of the differentially regulated proteins are involved in metabolism, folding, sorting, and degradation processes. In conclusion, acclimation under appropriate sub-lethal conditions can be used as a method to improve cell phenotypic characteristics such as viability, growth under certain conditions, and tolerance to downstream processes.
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Affiliation(s)
- Rasoul Shafiei
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
| | | | | | - Philippe Thonart
- Walloon Center for Industrial Biology, University of Liège, Liège, Belgium
| | - Frank Delvigne
- Microbial Processes and Interactions, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
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17
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Cohen A, Troib S, Dotan S, Najmuldeen H, Yesilkaya H, Kushnir T, Shagan M, Portnoi M, Nachmani H, Benisty R, Tal M, Ellis R, Chalifa-Caspi V, Dagan R, Nebenzahl YM. Streptococcus pneumoniae Cell Wall-Localized Trigger Factor Elicits a Protective Immune Response and Contributes to Bacterial Adhesion to the Host. Sci Rep 2019; 9:4295. [PMID: 30862841 PMCID: PMC6414539 DOI: 10.1038/s41598-019-40779-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 10/24/2018] [Indexed: 12/16/2022] Open
Abstract
Trigger factor (TF) has a known cytoplasmic function as a chaperone. In a previous study we showed that pneumococcal TF is also cell-wall localized and this finding combined with the immunogenic characteristic of TF, has led us to determine the vaccine potential of TF and decipher its involvement in pneumococcal pathogenesis. Bioinformatic analysis revealed that TF is conserved among pneumococci and has no human homologue. Immunization of mice with recombinant (r)TF elicited a protective immune response against a pneumococcal challenge, suggesting that TF contributes to pneumococcal pathogenesis. Indeed, rTF and an anti-rTF antiserum inhibited bacterial adhesion to human lung derived epithelial cells, indicating that TF contributes to the bacterial adhesion to the host. Moreover, bacteria lacking TF demonstrated reduced adhesion, in vitro, to lung-derived epithelial cells, neural cells and glial cells. The reduced adhesion could be restored by chromosomal complementation. Furthermore, bacteria lacking TF demonstrated significantly reduced virulence in a mouse model. Taken together, the ability of rTF to elicit a protective immune response, involvement of TF in bacterial adhesion, conservation of the protein among pneumococcal strains and the lack of human homologue, all suggest that rTF can be considered as a future candidate vaccine with a much broader coverage as compared to the currently available pneumococcal vaccines.
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Affiliation(s)
- Aviad Cohen
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Shani Troib
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | - Hastyar Najmuldeen
- Department of Infection, Immunity and Inflammation to Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom.,Department of Biology, College of Science, University of Sulaimani, Sulaimani, Iraq
| | - Hasan Yesilkaya
- Department of Infection, Immunity and Inflammation to Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
| | - Tatyana Kushnir
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Marilou Shagan
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Maxim Portnoi
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hannie Nachmani
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Rachel Benisty
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | | | - Vered Chalifa-Caspi
- Bioinformatics Core Facility, National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ron Dagan
- The Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yaffa Mizrachi Nebenzahl
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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18
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Kumar A, Alam A, Grover S, Pandey S, Tripathi D, Kumari M, Rani M, Singh A, Akhter Y, Ehtesham NZ, Hasnain SE. Peptidyl-prolyl isomerase-B is involved in Mycobacterium tuberculosis biofilm formation and a generic target for drug repurposing-based intervention. NPJ Biofilms Microbiomes 2019; 5:3. [PMID: 30675370 PMCID: PMC6333787 DOI: 10.1038/s41522-018-0075-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/15/2018] [Indexed: 01/03/2023] Open
Abstract
Tuberculosis (TB), a disease caused by Mycobacterium tuberculosis (M.tb), takes one human life every 15 s globally. Disease relapse occurs due to incomplete clearance of the pathogen and reactivation of the antibiotic tolerant bacilli. M.tb, like other bacterial pathogens, creates an ecosystem of biofilm formed by several proteins including the cyclophilins. We show that the M.tb cyclophilin peptidyl-prolyl isomerase (PpiB), an essential gene, is involved in biofilm formation and tolerance to anti-mycobacterial drugs. We predicted interaction between PpiB and US FDA approved drugs (cyclosporine-A and acarbose) by in-silico docking studies and this was confirmed by surface plasmon resonance (SPR) spectroscopy. While all these drugs inhibited growth of Mycobacterium smegmatis (M.smegmatis) when cultured in vitro, acarbose and cyclosporine-A showed bacteriostatic effect while gallium nanoparticle (GaNP) exhibited bactericidal effect. Cyclosporine-A and GaNP additionally disrupted M.tb H37Rv biofilm formation. Co-culturing M.tb in their presence resulted in significant (2–4 fold) decrease in dosage of anti-tubercular drugs- isoniazid and ethambutol. Comparison of the cyclosporine-A and acarbose binding sites in PpiB homologues of other biofilm forming infectious pathogens revealed that these have largely remained unaltered across bacterial species. Targeting bacterial biofilms could be a generic strategy for intervention against bacterial pathogens. Tuberculosis, caused by Mycobacterium tuberculosis, is the leading cause of death due to a single infectious agent. New therapeutic options are needed, and repurposing clinically approved drugs to destroy biofilms is an attractive approach, as these microbial communities are often less susceptible to antibiotics. A team lead by Seyed Hasnain at the Indian Institute of Technology Delhi identified an enzyme, PpiB, from M. tuberculosis that promoted biofilm formation and showed that PpiB interacts with several drugs that are currently used to treat diabetes, immunological diseases and cancer. These drugs destabilise M. tuberculosis biofilms in culture and enhanced the potency of two current anti-tuberculosis antibiotics. Future work is needed to test these medications against tuberculosis in humans, but given PpiB is found in different bacteria, there may be broader promise of using these repurposed drugs to combat other infections.
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Affiliation(s)
- Ashutosh Kumar
- 1JH-Institute of Molecular Medicine, Jamia Hamdard, New Delhi, India.,Present Address: Department of Microbiology, Tripura Central University, Suryamaninagar, Agartala, Tripura India
| | - Anwar Alam
- 1JH-Institute of Molecular Medicine, Jamia Hamdard, New Delhi, India.,2Molecular Infection and Functional Biology Lab, Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, New Delhi, India
| | - Sonam Grover
- 1JH-Institute of Molecular Medicine, Jamia Hamdard, New Delhi, India
| | - Saurabh Pandey
- 3National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, India.,11Present Address: Department of Biochemistry, Jamia Hamdard, New Delhi, India
| | - Deeksha Tripathi
- 2Molecular Infection and Functional Biology Lab, Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, New Delhi, India.,4Department of Microbiology, Central University of Rajasthan, Ajmer, Rajasthan India
| | - Monika Kumari
- 5Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Himachal Pradesh, India
| | - Mamta Rani
- 6Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology-Delhi, New Delhi, India
| | - Aditi Singh
- 7School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Yusuf Akhter
- 8Department of Biotechnology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Nasreen Z Ehtesham
- 3National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, India
| | - Seyed E Hasnain
- 1JH-Institute of Molecular Medicine, Jamia Hamdard, New Delhi, India.,2Molecular Infection and Functional Biology Lab, Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, New Delhi, India.,9Dr Reddy's Institute of Life Sciences, University of Hyderabad Campus, Prof CR Rao Road, Hyderabad, India
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19
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Sub-lethal antimicrobial photodynamic inactivation: an in vitro study on quorum sensing-controlled gene expression of Pseudomonas aeruginosa biofilm formation. Lasers Med Sci 2019; 34:1159-1165. [DOI: 10.1007/s10103-018-02707-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/10/2018] [Indexed: 10/27/2022]
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20
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Makvandi P, Jamaledin R, Jabbari M, Nikfarjam N, Borzacchiello A. Antibacterial quaternary ammonium compounds in dental materials: A systematic review. Dent Mater 2018; 34:851-867. [PMID: 29678327 DOI: 10.1016/j.dental.2018.03.014] [Citation(s) in RCA: 178] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 03/20/2018] [Accepted: 03/23/2018] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Quaternary ammonium compounds (QACs) represent one of the most effective classes of disinfectant agents in dental materials and resin nanocomposites. This reviews aims to give a wide overview on the research in the field of antibacterial QACs in dental materials and nanocomposites. METHOD An introduction to dental materials components as well as the microorganisms and methods of evaluation for the antimicrobial assays are presented. Then, the properties and synthesis route of QACs, as monomer and filler, are shown. Finally, antimicrobial monomers and fillers, specifically those contain quaternary ammonium salts (QASs), in dental materials are reviewed. RESULTS QACs have been used as monomer and micro/nanofiller in restorative dentistry. They possess one or more methacrylate functional groups to participate in polymerization reactions. QACs with multiple methacrylate groups can also be used as crosslinking agents. Furthermore, QACs with chain length from ∼12 to 16 have higher antimicrobial activity in cured dental resins. In general, increasing the chain length leads to a threshold value (critical point) and then it causes decrease in the antimicrobial activity. SIGNIFICANCE The current state of the art of dental materials and resin nanocomposites includes a wide variety of antimicrobial materials. Among them, QACs presents low cytotoxicity and excellent long-term antimicrobial activity without leaching out over time.
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Affiliation(s)
- Pooyan Makvandi
- Institute for Polymers, Composites and Biomaterials (IPCB), National Research Council (CNR), Naples, Italy; Institute for Advanced Studies in Basic Sciences, Zanjan, Iran.
| | - Rezvan Jamaledin
- Center for Advanced Biomaterials for Health Care, Istituto Italiano di Tecnologia (IIT@CRIB), Napels, Italy
| | - Mostafa Jabbari
- Swedish Centre for Resource Recovery, University of Borås, Borås SE-50190, Sweden
| | | | - Assunta Borzacchiello
- Institute for Polymers, Composites and Biomaterials (IPCB), National Research Council (CNR), Naples, Italy.
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21
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Skagia A, Vezyri E, Grados K, Venieraki A, Karpusas M, Katinakis P, Dimou M. Structure-Function Analysis of the Periplasmic Escherichia coli Cyclophilin PpiA in Relation to Biofilm Formation. J Mol Microbiol Biotechnol 2017; 27:228-236. [PMID: 28889121 DOI: 10.1159/000478858] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 06/12/2017] [Indexed: 12/30/2022] Open
Abstract
The presence of peptidyl-prolyl cis/trans isomerases (PPIases, EC: 5.2.1.8) in all domains of life indicates their biological importance. Cyclophilin PpiA, present in the periplasm of gram-negative bacteria, possesses PPIase activity but its physiological functions are still not clearly defined. Here, we demonstrate that the ΔppiA deletion strain from Escherichia coli exhibits an increased ability for biofilm formation and enhanced swimming motility compared to the wild-type strain. To identify structural features of PpiA which are necessary for the negative modulation of biofilm formation, we constructed a series of mutant PpiA proteins using a combination of error-prone and site-directed mutagenesis approaches. We show that the negative effect of PpiA on biofilm formation is not dependent on its PPIase activity, since PpiA mutants with a reduced PPIase activity are able to complement the ΔppiA strain during biofilm growth.
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Affiliation(s)
- Aggeliki Skagia
- Laboratory of General and Agricultural Microbiology, Faculty of Crop Science, Agricultural University of Athens, Athens, Greece
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22
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KESKİN E, BAĞLAR S. ACID TOLERANCE RESPONCE OF CARIOGENIC MICROORGANISMS AND MALOLACTIC FERMENTATION. CUMHURIYET DENTAL JOURNAL 2017. [DOI: 10.7126/cumudj.345960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Deficiency of RgpG Causes Major Defects in Cell Division and Biofilm Formation, and Deficiency of LytR-CpsA-Psr Family Proteins Leads to Accumulation of Cell Wall Antigens in Culture Medium by Streptococcus mutans. Appl Environ Microbiol 2017; 83:AEM.00928-17. [PMID: 28687645 DOI: 10.1128/aem.00928-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/29/2017] [Indexed: 12/20/2022] Open
Abstract
Streptococcus mutans is known to possess rhamnose-glucose polysaccharide (RGP), a major cell wall antigen. S. mutans strains deficient in rgpG, encoding the first enzyme of the RGP biosynthesis pathway, were constructed by allelic exchange. The rgpG deficiency had no effect on growth rate but caused major defects in cell division and altered cell morphology. Unlike the coccoid wild type, the rgpG mutant existed primarily in chains of swollen, "squarish" dividing cells. Deficiency of rgpG also causes significant reduction in biofilm formation (P < 0.01). Double and triple mutants with deficiency in brpA and/or psr, genes coding for the LytR-CpsA-Psr family proteins BrpA and Psr, which were previously shown to play important roles in cell envelope biogenesis, were constructed using the rgpG mutant. There were no major differences in growth rates between the wild-type strain and the rgpG brpA and rgpG psr double mutants, but the growth rate of the rgpG brpA psr triple mutant was reduced drastically (P < 0.001). Under transmission electron microscopy, both double mutants resembled the rgpG mutant, while the triple mutant existed as giant cells with multiple asymmetric septa. When analyzed by immunoblotting, the rgpG mutant displayed major reductions in cell wall antigens compared to the wild type, while little or no signal was detected with the double and triple mutants and the brpA and psr single mutants. These results suggest that RgpG in S. mutans plays a critical role in cell division and biofilm formation and that BrpA and Psr may be responsible for attachment of cell wall antigens to the cell envelope.IMPORTANCEStreptococcus mutans, a major etiological agent of human dental caries, produces rhamnose-glucose polysaccharide (RGP) as the major cell wall antigen. This study provides direct evidence that deficiency of RgpG, the first enzyme of the RGP biosynthesis pathway, caused major defects in cell division and morphology and reduced biofilm formation by S. mutans, indicative of a significant role of RGP in cell division and biofilm formation in S. mutans These results are novel not only in S. mutans, but also other streptococci that produce RGP. This study also shows that the LytR-CpsA-Psr family proteins BrpA and Psr in S. mutans are involved in attachment of RGP and probably other cell wall glycopolymers to the peptidoglycan. In addition, the results also suggest that BrpA and Psr may play a direct role in cell division and biofilm formation in S. mutans This study reveals new potential targets to develop anticaries therapeutics.
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Chen J, Li T, Zhou X, Cheng L, Huo Y, Zou J, Li Y. Characterization of the clustered regularly interspaced short palindromic repeats sites in Streptococcus mutans isolated from early childhood caries patients. Arch Oral Biol 2017; 83:174-180. [PMID: 28783550 DOI: 10.1016/j.archoralbio.2017.07.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/27/2017] [Accepted: 07/27/2017] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The aim of this study was to analyze the characteristics of the clustered regularly interspaced short palindromic repeats (CRISPR) sites in 45 clinical Streptococcus mutans strains and their relationship to the clinical manifestations of early childhood caries (ECC). METHODS Forty-five S. mutans strains were isolated from the plaque samples taken from sixty-three children. CRISPR sites were sequenced and BLAST was used to compare these sites to those in the CRISPRTarget database. The association between the distribution of CRISPR sites and the manifestation of caries was analyzed by Chi-Square test. Further, biofilm formation (by crystal violet staining) and the synthesis of polysaccharide (by anthrone-sulfuric method) of all clinical isolated S. mutans strains with both CRISPR sites and no CRISPR site were comapared. Finally, acidogenicity and acidurity of two typical strains were determined using pH drop and acid tolerance assays. Biofilm formation and EPS synthesis by two typical strains were compared by 3D CLSM (Confocal Laser Scanning Microscope) assays and the expression of gtf genes were evaluated using qPCR. RESULTS We found that most of the spacers in the clinical S. mutans strains were derived from Streptococcus phages APCM01 and M102. The number of CRISPR sites in these strains was associated with the clinical manifestations of ECC. Moreover, we found that the biofilm formation and EPS synthesis ability of the S. mutans strains with both CRISPR sites was significant improved. CONCLUSIONS An association was found between the distribution of CRISPR sites and the clinical manifestations of caries. The CRISPR sites might contribute to the cariogenic potential of S. mutans.
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Affiliation(s)
- Jing Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Tiancheng Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Lei Cheng
- Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuanyuan Huo
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Zou
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuqing Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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Pemmaraju SC, Padmapriya K, Pruthi PA, Prasad R, Pruthi V. Impact of oxidative and osmotic stresses on Candida albicans biofilm formation. BIOFOULING 2016; 32:897-909. [PMID: 27472386 DOI: 10.1080/08927014.2016.1212021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 07/05/2016] [Indexed: 06/06/2023]
Abstract
Candida albicans possesses an ability to grow under different host-driven stress conditions by developing robust protective mechanisms. In this investigation the focus was on the impact of osmotic (2M NaCl) and oxidative (5 mM H2O2) stress conditions during C. albicans biofilm formation. Oxidative stress enhanced extracellular DNA secretion into the biofilm matrix, increased the chitin level, and reduced virulence factors, namely phospholipase and proteinase activity, while osmotic stress mainly increased extracellular proteinase and decreased phospholipase activity. Fourier transform infrared and nuclear magnetic resonance spectroscopy analysis of mannan isolated from the C. albicans biofilm cell wall revealed a decrease in mannan content and reduced β-linked mannose moieties under stress conditions. The results demonstrate that C. albicans adapts to oxidative and osmotic stress conditions by inducing biofilm formation with a rich exopolymeric matrix, modulating virulence factors as well as the cell wall composition for its survival in different host niches.
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Affiliation(s)
- Suma C Pemmaraju
- a Department of Biotechnology, Indian Institute of Technology Roorkee , Roorkee , Uttarakhand , India
| | - Kumar Padmapriya
- a Department of Biotechnology, Indian Institute of Technology Roorkee , Roorkee , Uttarakhand , India
| | - Parul A Pruthi
- a Department of Biotechnology, Indian Institute of Technology Roorkee , Roorkee , Uttarakhand , India
| | | | - Vikas Pruthi
- a Department of Biotechnology, Indian Institute of Technology Roorkee , Roorkee , Uttarakhand , India
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Fan D, Zhou Q, Liu C, Zhang J. Functional characterization of the Helicobacter pylori chaperone protein HP0795. Microbiol Res 2016; 193:11-19. [PMID: 27825478 DOI: 10.1016/j.micres.2016.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/09/2016] [Accepted: 08/20/2016] [Indexed: 12/12/2022]
Abstract
Trigger factor (TF) is one of the multiple bacterial chaperone proteins interacting with nascent peptides and facilitating their folding in bacteria. While TF is well-characterized in E. coli, HP0795, a TF-like homologue gene identified earlier in the pathogenic Helicobacter pylori (H. pylori), has not been studied biochemically to date. To characterize its function as a chaperone, we performed 3D-modeling, cross-linking and in vitro enzyme assays to HP0795 in vitro. Our results show that HP0795 possesses peptidyl prolyl cis-trans isomerase activity and exhibits a dimeric structure in solution. In addition, stable expression of HP0795 in a series of well-characterized E. coli chaperone-deficient strains rescued the growth defects in these mutants. Furthermore, we showed that the presence of HP0795 greatly reduced protein aggregation caused by deficiencies of chaperones in these strains. In contrast to other chaperone genes in H. pylori, gene expression of HP0795 displays little induction under acidic pH conditions. Together, our results suggest that HP0795 is a constitutively expressed TF-like protein of the prokaryotic chaperone family that may not play a major role in acid response. Given the pathogenic properties of H. pylori, our insights might provide new avenues for potential future medical intervention for H. pylori-related conditions.
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Affiliation(s)
- Dongjie Fan
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
| | - Qiming Zhou
- School of Life Science and Technology, Harbin Institute of Technology, 2 Yikuang Street, Harbin, 150080, China; Beijing CapitalBio MedLab, 88 D2, Branch Six Street, Economic and Technological Development Zone, Beijing 101111, China
| | - Chuanpeng Liu
- School of Life Science and Technology, Harbin Institute of Technology, 2 Yikuang Street, Harbin, 150080, China
| | - Jianzhong Zhang
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
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Shrivastava AK, Pandey S, Dietz KJ, Singh PK, Singh S, Rai R, Rai LC. Overexpression of AhpC enhances stress tolerance and N2-fixation in Anabaena by upregulating stress responsive genes. Biochim Biophys Acta Gen Subj 2016; 1860:2576-2588. [PMID: 27487031 DOI: 10.1016/j.bbagen.2016.07.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/18/2016] [Accepted: 07/28/2016] [Indexed: 02/07/2023]
Abstract
The study explores the significance of peroxides in regulating the CO2- and N2-fixation capacities in Anabaena sp. PCC7120. To this end Anabaena strains were generated carrying an extra copy of ahpC (An+ahpC) or by deleting from their endogenous functional ahpC (AnΔahpC). AhpC levels were 2.2- to 6.0-fold higher in An+ahpC than in wild type. An+ahpC revealed 1.4- to 2-fold upregulation of photosystems I and II, nitrogenase, superoxide dismutase and catalase activities while same activities were 1.3- to 2.5-fold downregulated in the insertional mutant (AnΔahpC) compared to the wild type. Peroxide, superoxide and malondialdehyde contents were low in An+ahpC and high in AnΔahpC. Growth was inhibited in AnΔahpC by approximately 40-60% compared to a 33-40% enhanced growth in An+ahpC under selected stresses. Most interestingly, heterocyst frequency was increased in An+ahpC. In order to address transcriptional and posttranscriptional effects, transcripts of genes including groEL, fld, kat, gor, gst, dps, bfr, tf, sodA, dnaK, prx, uspA, pcs and apx were quantified and found to be increased 1.33- to 7.70-fold in unstressed and 1.76- to 13.80-fold in stressed An+ahpC. In a converse manner, they were downregulated by 1.20- to 7.50-fold in unstressed and 1.23 to 10.20-fold in stressed AnΔahpC. It is concluded that the level of AhpC controls a major set of metabolic and developmental genes in normal and stress conditions and thus likely is in the core of the redox regulatory system of Anabaena.
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Affiliation(s)
- Alok Kumar Shrivastava
- Department of Chemical Engineering, IIT, Banaras Hindu University, Varanasi-221005, India
| | - Sarita Pandey
- Cyanobacterial Stress Biology & Biotechnology Section, Molecular Biology Division, BARC, Mumbai-400094, India
| | - Karl Josef Dietz
- Department of Biochemistry and Physiology of Plants, Faculty of Biology, University of Bielefeld, Bielefeld - 100131, Germany
| | - Prashant Kumar Singh
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi-221005, India
| | - Shilpi Singh
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi-221005, India
| | - Ruchi Rai
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi-221005, India
| | - Lal Chand Rai
- Molecular Biology Section, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi-221005, India.
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Abstract
Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.
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Effects of Low-Dose Amoxicillin on Staphylococcus aureus USA300 Biofilms. Antimicrob Agents Chemother 2016; 60:2639-51. [PMID: 26856828 DOI: 10.1128/aac.02070-15] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 01/31/2016] [Indexed: 01/01/2023] Open
Abstract
Previous studies showed that sub-MIC levels of β-lactam antibiotics stimulate biofilm formation in most methicillin-resistant Staphylococcus aureus (MRSA) strains. Here, we investigated this process by measuring the effects of sub-MIC amoxicillin on biofilm formation by the epidemic community-associated MRSA strain USA300. We found that sub-MIC amoxicillin increased the ability of USA300 cells to attach to surfaces and form biofilms under both static and flow conditions. We also found that USA300 biofilms cultured in sub-MIC amoxicillin were thicker, contained more pillar and channel structures, and were less porous than biofilms cultured without antibiotic. Biofilm formation in sub-MIC amoxicillin correlated with the production of extracellular DNA (eDNA). However, eDNA released by amoxicillin-induced cell lysis alone was evidently not sufficient to stimulate biofilm. Sub-MIC levels of two other cell wall-active agents with different mechanisms of action-d-cycloserine and fosfomycin-also stimulated eDNA-dependent biofilm, suggesting that biofilm formation may be a mechanistic adaptation to cell wall stress. Screening a USA300 mariner transposon library for mutants deficient in biofilm formation in sub-MIC amoxicillin identified numerous known mediators of S. aureus β-lactam resistance and biofilm formation, as well as novel genes not previously associated with these phenotypes. Our results link cell wall stress and biofilm formation in MRSA and suggest that eDNA-dependent biofilm formation by strain USA300 in low-dose amoxicillin is an inducible phenotype that can be used to identify novel genes impacting MRSA β-lactam resistance and biofilm formation.
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30
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Crowley PJ, Brady LJ. Evaluation of the effects of Streptococcus mutans chaperones and protein secretion machinery components on cell surface protein biogenesis, competence, and mutacin production. Mol Oral Microbiol 2015; 31:59-77. [PMID: 26386361 DOI: 10.1111/omi.12130] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2015] [Indexed: 11/29/2022]
Abstract
The respective contributions of components of the protein translocation/maturation machinery to cell surface biogenesis in Streptococcus mutans are not fully understood. Here we used a genetic approach to characterize the effects of deletion of genes encoding the ribosome-associated chaperone RopA (Trigger Factor), the surface-localized foldase PrsA, and the membrane-localized chaperone insertases YidC1 and YidC2, both singly and in combination, on bacterial growth, chain length, self-aggregation, cell surface hydrophobicity, autolysis, and antigenicity of surface proteins P1 (AgI/II, PAc), WapA, GbpC, and GtfD. The single and double deletion mutants, as well as additional mutant strains lacking components of the signal recognition particle pathway, were also evaluated for their effects on mutacin production and genetic competence.
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Affiliation(s)
- P J Crowley
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - L J Brady
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
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31
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Abstract
We are rapidly returning to a world in which bacterial infections are a major health issue. Pathogenic bacteria are able to colonize and cause pathology due to the possession of virulence factors such as adhesins, invasins, evasins and toxins. These are generally specifically evolved proteins with selective actions. It is, therefore, surprising that most human bacterial pathogens employ moonlighting proteins as virulence factors. Currently, >90 bacterial species employ one or more moonlighting protein families to aid colonization and induce disease. These organisms employ 90 moonlighting bacterial protein families and these include enzymes of the glycolytic pathway, tricarboxylic acid (TCA) cycle, hexosemonophosphate shunt, glyoxylate cycle and a range of other metabolic enzymes, proteases, transporters and, also, molecular chaperones and protein-folding catalysts. These proteins have homologues in eukaryotes and only a proportion of the moonlighting proteins employed are solely bacterial in origin. Bacterial moonlighting proteins can be divided into those with single moonlighting functions and those with multiple additional biological actions. These proteins contribute significantly to the population of virulence factors employed by bacteria and some are obvious therapeutic targets. Where examined, bacterial moonlighting proteins bind to target ligands with high affinity. A major puzzle is the evolutionary mechanism(s) responsible for bacterial protein moonlighting and a growing number of highly homologous bacterial moonlighting proteins exhibit widely different moonlighting actions, suggesting a lack in our understanding of the mechanism of evolution of protein active sites.
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Méndez JA, Mateos J, Beceiro A, Lopez M, Tomás M, Poza M, Bou G. Quantitative proteomic analysis of host--pathogen interactions: a study of Acinetobacter baumannii responses to host airways. BMC Genomics 2015; 16:422. [PMID: 26025090 PMCID: PMC4449591 DOI: 10.1186/s12864-015-1608-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 05/01/2015] [Indexed: 01/23/2023] Open
Abstract
Background Acinetobacter baumannii is a major health problem. The most common infection caused by A. baumannii is hospital acquired pneumonia, and the associated mortality rate is approximately 50 %. Neither in vivo nor ex vivo expression profiling has been performed at the proteomic or transcriptomic level for pneumonia caused by A. baumannii. In this study, we characterized the proteome of A. baumannii under conditions that simulate those found in the airways, to gain some insight into how A. baumannii adapts to the host and to improve knowledge about the pathogenesis and virulence of this bacterium. A clinical strain of A. baumannii was grown under different conditions: in the presence of bronchoalveolar lavage fluid from infected rats, of RAW 264.7 cells to simulate conditions in the respiratory tract and in control conditions. We used iTRAQ labelling and LC-MALDI-TOF/TOF to investigate how A. baumannii responds on exposure to macrophages/BALF. Results 179 proteins showed differential expression. In both models, proteins involved in the following processes were over-expressed: (i) pathogenesis and virulence (OmpA, YjjK); (ii) cell wall/membrane/envelope biogenesis (MurC); (iii) energy production and conversion (acetyl-CoA hydrolase); and (iv) translation (50S ribosomal protein L9). Proteins involved in the following were under-expressed: (i) lipid metabolism (short-chain dehydrogenase); (ii) amino acid metabolism and transport (aspartate aminotransferase); (iii) unknown function (DNA-binding protein); and (iv) inorganic ion transport and metabolism (hydroperoxidase). Conclusions We observed alterations in cell wall synthesis and identified 2 upregulated virulence-associated proteins with >15 peptides/protein in both ex vivo models (OmpA and YjjK), suggesting that these proteins are fundamental for pathogenesis and virulence in the airways. This study is the first comprehensive overview of the ex vivo proteome of A. baumannii and is an important step towards identification of diagnostic biomarkers, novel drug targets and potential vaccine candidates in the fight against pneumonia caused by A. baumannii. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1608-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jose Antonio Méndez
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - Jesús Mateos
- Grupo de Proteomica-PBR2-ProteoRed/ISCIII-Servicio de Reumatologia, A Coruña, Spain.
| | - Alejandro Beceiro
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - María Lopez
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - María Tomás
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - Margarita Poza
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - Germán Bou
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
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Microbial peptidyl-prolyl cis/trans isomerases (PPIases): virulence factors and potential alternative drug targets. Microbiol Mol Biol Rev 2015; 78:544-71. [PMID: 25184565 DOI: 10.1128/mmbr.00015-14] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Initially discovered in the context of immunomodulation, peptidyl-prolyl cis/trans isomerases (PPIases) were soon identified as enzymes catalyzing the rate-limiting protein folding step at peptidyl bonds preceding proline residues. Intense searches revealed that PPIases are a superfamily of proteins consisting of three structurally distinguishable families with representatives in every described species of prokaryote and eukaryote and, recently, even in some giant viruses. Despite the clear-cut enzymatic activity and ubiquitous distribution of PPIases, reports on solely PPIase-dependent biological roles remain scarce. Nevertheless, they have been found to be involved in a plethora of biological processes, such as gene expression, signal transduction, protein secretion, development, and tissue regeneration, underscoring their general importance. Hence, it is not surprising that PPIases have also been identified as virulence-associated proteins. The extent of contribution to virulence is highly variable and dependent on the pleiotropic roles of a single PPIase in the respective pathogen. The main objective of this review is to discuss this variety in virulence-related bacterial and protozoan PPIases as well as the involvement of host PPIases in infectious processes. Moreover, a special focus is given to Legionella pneumophila macrophage infectivity potentiator (Mip) and Mip-like PPIases of other pathogens, as the best-characterized virulence-related representatives of this family. Finally, the potential of PPIases as alternative drug targets and first tangible results are highlighted.
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Liao S, Bitoun JP, Nguyen AH, Bozner D, Yao X, Wen ZT. Deficiency of PdxR in Streptococcus mutans affects vitamin B6 metabolism, acid tolerance response and biofilm formation. Mol Oral Microbiol 2015; 30:255-68. [PMID: 25421565 DOI: 10.1111/omi.12090] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2014] [Indexed: 11/28/2022]
Abstract
Streptococcus mutans, a key etiological agent of the human dental caries, lives primarily on the tooth surface in tenacious biofilms. The SMU864 locus, designated pdxR, is predicted to encode a member of the novel MocR/GabR family proteins, which are featured with a winged helix DNA-binding N-terminal domain and a C-terminal domain highly homologous to the pyridoxal phosphate-dependent aspartate aminotransferases. A pdxR-deficient mutant, TW296, was constructed using allelic exchange. PdxR deficiency in S. mutans had little effect on cell morphology and growth when grown in brain heart infusion. However, when compared with its parent strain, UA159, the PdxR-deficient mutant displayed major defects in acid tolerance response and formed significantly fewer biofilms (P < 0.01). When analyzed by real-time polymerase chain reaction, PdxR deficiency was found to drastically reduce expression of an apparent operon encoding a pyridoxal kinase (SMU865) and a pyridoxal permease (SMU866) of the salvage pathway of vitamin B6 biosynthesis. In addition, PdxR deficiency also altered the expression of genes for ClpL protease, glucosyltransferase B and adhesin SpaP, which are known to play important roles in stress tolerance and biofilm formation. Consistently, PdxR-deficiency affected the growth of the deficient mutant when grown in defined medium with and without vitamin B6 . Further studies revealed that although S. mutans is known to require vitamin B6 to grow in defined medium, B6 vitamers, especially pyridoxal, were strongly inhibitory at millimolar concentrations, against S. mutans growth and biofilm formation. Our results suggest that PdxR in S. mutans plays an important role in regulation of vitamin B6 metabolism, acid tolerance response and biofilm formation.
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Affiliation(s)
- S Liao
- Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - J P Bitoun
- Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - A H Nguyen
- Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - D Bozner
- Center of Excellence for Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - X Yao
- Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Z T Wen
- Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Center of Excellence for Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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Ünal CM, Steinert M. FKBPs in bacterial infections. Biochim Biophys Acta Gen Subj 2014; 1850:2096-102. [PMID: 25529296 DOI: 10.1016/j.bbagen.2014.12.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 12/11/2014] [Accepted: 12/13/2014] [Indexed: 02/05/2023]
Abstract
BACKGROUND FK506-binding proteins (FKBPs) contain a domain with peptidyl-prolyl-cis/trans-isomerase (PPIase) activity and bind the immunosuppressive drugs FK506 and rapamycin. FKBPs belong to the immunophilin family and are found in eukaryotes and bacteria. SCOPE OF REVIEW In this review we describe two major groups of bacterial virulence-associated FKBPs, the trigger factor and Mip-like PPIases. Moreover, we discuss the contribution of host FKBPs in bacterial infection processes. MAJOR CONCLUSIONS Since PPIases are regarded as alternative antiinfective drug targets we highlight current research strategies utilizing pipecolinic acid and cycloheximide derivatives as well as substrate based inhibitors. GENERAL SIGNIFICANCE The current research strategies suggest a beneficial synergism of drug development and basic research. This article is part of a Special Issue entitled Proline-directed Foldases: Cell Signaling Catalysts and Drug Targets.
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Affiliation(s)
- Can M Ünal
- Türk-Alman Üniversitesi, Fen Fakültesi, Istanbul, Turkey; Technische Universität Braunschweig, Institut für Mikrobiologie, Braunschweig, Germany
| | - Michael Steinert
- Technische Universität Braunschweig, Institut für Mikrobiologie, Braunschweig, Germany; Helmholtz Centre for Infection Research, Braunschweig, Germany.
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Peptidylprolyl cis–trans isomerases of Legionella pneumophila: virulence, moonlighting and novel therapeutic targets. Biochem Soc Trans 2014; 42:1728-33. [DOI: 10.1042/bst20140202] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Legionella pneumophila, typically a parasite of free-living protozoa, can also replicate in human alveolar macrophages and lung epithelial cells causing Legionnaires’ disease in humans, a severe atypical pneumonia. The pathogen encodes six peptidylprolyl cis–trans isomerases (PPIases), which generally accelerate folding of prolyl peptide bonds, and influence protein folding. PPIases can be divided into three classes, cyclophilins, parvulins and FK506-binding proteins (FKBPs). They contribute to a multitude of cellular functions including bacterial virulence. In the present review, we provide an overview of L. pneumophila PPIases, discussing their known and anticipated functions as well as moonlighting phenomena. By taking the example of the macrophage infectivity potentiator (Mip) of L. pneumophila, we highlight the potential of PPIases as promising drug targets.
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Cheng X, Xu X, Chen J, Zhou X, Cheng L, Li M, Li J, Wang R, Jia W, Li YQ. Effects of simulated microgravity on Streptococcus mutans physiology and biofilm structure. FEMS Microbiol Lett 2014; 359:94-101. [PMID: 25109245 DOI: 10.1111/1574-6968.12573] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/05/2014] [Accepted: 08/05/2014] [Indexed: 02/05/2023] Open
Abstract
Long-term spaceflights will eventually become an inevitable occurrence. Previous studies have indicated that oral infectious diseases, including dental caries, were more prevalent in astronauts due to the effect of microgravity. However, the impact of the space environment, especially the microgravity environment, on the virulence factors of Streptococcus mutans, a major caries-associated bacterium, is yet to be explored. In the present study, we investigated the impact of simulated microgravity on the physiology and biofilm structure of S. mutans. We also explored the dual-species interaction between S. mutans and Streptococcus sanguinis under a simulated microgravity condition. Results indicated that the simulated microgravity condition can enhance the acid tolerance ability, modify the biofilm architecture and extracellular polysaccharide distribution of S. mutans, and increase the proportion of S. mutans within a dual-species biofilm, probably through the regulation of various gene expressions. We hypothesize that the enhanced competitiveness of S. mutans under simulated microgravity may cause a multispecies micro-ecological imbalance, which would result in the initiation of dental caries. Our current findings are consistent with previous studies, which revealed a higher astronaut-associated incidence of caries. Further research is required to explore the detailed mechanisms.
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Affiliation(s)
- Xingqun Cheng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Streptococcus mutans extracellular DNA is upregulated during growth in biofilms, actively released via membrane vesicles, and influenced by components of the protein secretion machinery. J Bacteriol 2014; 196:2355-66. [PMID: 24748612 DOI: 10.1128/jb.01493-14] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Streptococcus mutans, a major etiological agent of human dental caries, lives primarily on the tooth surface in biofilms. Limited information is available concerning the extracellular DNA (eDNA) as a scaffolding matrix in S. mutans biofilms. This study demonstrates that S. mutans produces eDNA by multiple avenues, including lysis-independent membrane vesicles. Unlike eDNAs from cell lysis that were abundant and mainly concentrated around broken cells or cell debris with floating open ends, eDNAs produced via the lysis-independent pathway appeared scattered but in a structured network under scanning electron microscopy. Compared to eDNA production of planktonic cultures, eDNA production in 5- and 24-h biofilms was increased by >3- and >1.6-fold, respectively. The addition of DNase I to growth medium significantly reduced biofilm formation. In an in vitro adherence assay, added chromosomal DNA alone had a limited effect on S. mutans adherence to saliva-coated hydroxylapatite beads, but in conjunction with glucans synthesized using purified glucosyltransferase B, the adherence was significantly enhanced. Deletion of sortase A, the transpeptidase that covalently couples multiple surface-associated proteins to the cell wall peptidoglycan, significantly reduced eDNA in both planktonic and biofilm cultures. Sortase A deficiency did not have a significant effect on membrane vesicle production; however, the protein profile of the mutant membrane vesicles was significantly altered, including reduction of adhesin P1 and glucan-binding proteins B and C. Relative to the wild type, deficiency of protein secretion and membrane protein insertion machinery components, including Ffh, YidC1, and YidC2, also caused significant reductions in eDNA.
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Castanié-Cornet MP, Bruel N, Genevaux P. Chaperone networking facilitates protein targeting to the bacterial cytoplasmic membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1442-56. [PMID: 24269840 DOI: 10.1016/j.bbamcr.2013.11.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 11/10/2013] [Accepted: 11/13/2013] [Indexed: 12/22/2022]
Abstract
Nascent polypeptides emerging from the ribosome are assisted by a pool of molecular chaperones and targeting factors, which enable them to efficiently partition as cytosolic, integral membrane or exported proteins. Extensive genetic and biochemical analyses have significantly expanded our knowledge of chaperone tasking throughout this process. In bacteria, it is known that the folding of newly-synthesized cytosolic proteins is mainly orchestrated by three highly conserved molecular chaperones, namely Trigger Factor (TF), DnaK (HSP70) and GroEL (HSP60). Yet, it has been reported that these major chaperones are strongly involved in protein translocation pathways as well. This review describes such essential molecular chaperone functions, with emphasis on both the biogenesis of inner membrane proteins and the post-translational targeting of presecretory proteins to the Sec and the twin-arginine translocation (Tat) pathways. Critical interplay between TF, DnaK, GroEL and other molecular chaperones and targeting factors, including SecB, SecA, the signal recognition particle (SRP) and the redox enzyme maturation proteins (REMPs) is also discussed. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Marie-Pierre Castanié-Cornet
- Laboratoire de Microbiologie et Génétique Moléculaire (LMGM), Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse, France
| | - Nicolas Bruel
- Laboratoire de Microbiologie et Génétique Moléculaire (LMGM), Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse, France
| | - Pierre Genevaux
- Laboratoire de Microbiologie et Génétique Moléculaire (LMGM), Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, Toulouse, France.
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Dufour D, Lévesque CM. Bacterial behaviors associated with the quorum-sensing peptide pheromone ('alarmone') in streptococci. Future Microbiol 2013; 8:593-605. [PMID: 23642115 DOI: 10.2217/fmb.13.23] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Streptococci are among the predominant bacterial species living in the human body. They are normally harmless bacteria, but have the ability to cause diverse infections, ranging from mild (e.g., tooth decay and sore throat) to life-threatening (e.g., endocarditis and meningitis). Streptococci have evolved various means of coping with the deleterious effects of environmental stressors and avoiding the host immune system. Recently, several studies have shown that streptococci colonizing the mouth and upper respiratory tract are able to mount complex stress responses in order to persist and successfully survive competition in their ecological niche. Using a small quorum-sensing peptide pheromone acting as a stress-inducible 'alarmone', oral streptococci synchronize the gene expression of a specific group of cells to coordinate important biological activities.
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Affiliation(s)
- Delphine Dufour
- Dental Research Institute, Faculty of Dentistry, University of Toronto, 124 Edward St, Room 454B, Toronto, ON, M5G 1G6, Canada
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Zheng X, Zhang K, Zhou X, Liu C, Li M, Li Y, Wang R, Li Y, Li J, Shi W, Xu X. Involvement of gshAB in the interspecies competition within oral biofilm. J Dent Res 2013; 92:819-24. [PMID: 23872989 DOI: 10.1177/0022034513498598] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Although Streptococcus sanguinis has been reported to produce H2O2 to gain a competitive edge over Streptococcus mutans, the molecular mechanisms evolved by S. mutans to counter this "peer stress" are still to be identified. The current study was designed to investigate the ecological role of glutathione synthetase (gshAB) in the interspecies interaction between S. mutans and S. sanguinis. A gshAB in-frame deletion strain of S. mutans was constructed, and its phenotypic traits were characterized. The spatio-temporal interaction of the gshAB mutant with S. sanguinis was further investigated in a dual-species biofilm model by fluorescence in situ hybridization. We found that, although less tolerant for H2O2, the gshAB mutant produced more extracellular polysaccharides by up-regulating gtfs expression, so as to cluster as condensed microcolonies. In addition, the mutant was more susceptible to the conditioned medium of S. sanguinis, and its competitiveness was significantly compromised. Taken together, we believe that gshAB is essential for the competitiveness and prevalence of S. mutans through detoxifying the H2O2 produced by S. sanguinis. Given the ecological importance of bacterial equilibrium within the oral biofilm, gshAB may represent a promising target to modulate the S. mutans/S. sanguinis ratio under cariogenic conditions, thus contributing to the management of dental caries.
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Affiliation(s)
- X Zheng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
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Bitoun JP, Liao S, McKey BA, Yao X, Fan Y, Abranches J, Beatty WL, Wen ZT. Psr is involved in regulation of glucan production, and double deficiency of BrpA and Psr is lethal in Streptococcus mutans. MICROBIOLOGY-SGM 2013; 159:493-506. [PMID: 23288544 DOI: 10.1099/mic.0.063032-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Streptococcus mutans, the primary causative agent of dental caries, contains two paralogues of the LytR-CpsA-Psr family proteins encoded by brpA and psr, respectively. Previous studies have shown that BrpA plays an important role in cell envelope biogenesis/homeostasis and affects stress responses and biofilm formation by Strep. mutans, traits critical to cariogenicity of this bacterium. In this study, a Psr-deficient mutant, TW251, was constructed. Characterization of TW251 showed that deficiency of Psr did not have any major impact on growth rate. However, when subjected to acid killing at pH 2.8, the survival rate of TW251 was decreased dramatically compared with the parent strain UA159. In addition, TW251 also displayed major defects in biofilm formation, especially during growth with sucrose. When compared to UA159, the biofilms of TW251 were mainly planar and devoid of extracellular glucans. Real-time-PCR and Western blot analyses revealed that deficiency of Psr significantly decreased the expression of glucosyltransferase C, a protein known to play a major role in biofilm formation by Strep. mutans. Transmission electron microscopy analysis showed that deficiency of BrpA caused alterations in cell envelope and cell division, and the most significant defects were observed in TW314, a Psr-deficient and BrpA-down mutant. No such effects were observed with Psr mutant TW251 under similar conditions. These results suggest that while there are similarities in functions between BrpA and Psr, distinctive differences also exist between these two paralogues. Like Bacillus subtilis but different from Staphylococcus aureus, a functional BrpA or Psr is required for viability in Strep. mutans.
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Affiliation(s)
- Jacob P Bitoun
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Sumei Liao
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Briggs A McKey
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Xin Yao
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Yuwei Fan
- Department of Comprehensive Dentistry and Biomaterials, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Jacqueline Abranches
- Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Wandy L Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA
| | - Zezhang T Wen
- Department of Microbiology, Immunology, and Parasitology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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Sharma A, Arya DK, Sagar V, Bergmann R, Chhatwal GS, Johri AK. Identification of potential universal vaccine candidates against group A Streptococcus by using high throughput in silico and proteomics approach. J Proteome Res 2012. [PMID: 23181284 DOI: 10.1021/pr3005265] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Streptococcus pyogenes or group A Streptococcus (GAS) causes ~700 million human infections each year, resulting in over 500,000 deaths. The development of a commercial GAS vaccine is hampered due to high strain and serotype diversity in different geographical regions, and the generation of cross-reactive antibodies that may induce autoimmune disease. There is an urgent need to search for alternative vaccine candidates. High throughput multigenome data mining coupled with proteomics seems to be a promising approach to identify the universal vaccine candidates. In the present study, in silico analysis led to prediction of 147 proteins as universal vaccine candidates. Distribution pattern of these predicted candidates was explored in nonsequenced Indian GAS strains (n = 20) by using DNA array hybridization validating in silico analysis. High throughput analyses of surface proteins using 1D-SDS-PAGE coupled with ESI-LC-MS/MS was applied on highly (M49) and less (M1) invasive GAS strains of Indian origin. Comparative proteomics analysis revealed that highly invasive GAS M49 had metabolically more active membrane associated protein machinery than less invasive M1. Further, by overlapping proteomics data with in silico predicted vaccine candidate genes, 52 proteins were identified as probable universal vaccine candidates, which were expressed in these GAS serotypes. These proteins can further be investigated as universal vaccine candidates against GAS. Moreover, this robust approach may serve as a model that can be applied to identify the universal vaccine candidates in case of other pathogenic bacteria with high strain and genetic diversity.
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Affiliation(s)
- Abhinay Sharma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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Intracellularly induced cyclophilins play an important role in stress adaptation and virulence of Brucella abortus. Infect Immun 2012; 81:521-30. [PMID: 23230297 DOI: 10.1128/iai.01125-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Brucella is an intracellular bacterial pathogen that causes the worldwide zoonotic disease brucellosis. Brucella virulence relies on its ability to transition to an intracellular lifestyle within host cells. Thus, this pathogen must sense its intracellular localization and then reprogram gene expression for survival within the host cell. A comparative proteomic investigation was performed to identify differentially expressed proteins potentially relevant for Brucella intracellular adaptation. Two proteins identified as cyclophilins (CypA and CypB) were overexpressed in the intracellular environment of the host cell in comparison to laboratory-grown Brucella. To define the potential role of cyclophilins in Brucella virulence, a double-deletion mutant was constructed and its resulting phenotype was characterized. The Brucella abortus ΔcypAB mutant displayed increased sensitivity to environmental stressors, such as oxidative stress, pH, and detergents. In addition, the B. abortus ΔcypAB mutant strain had a reduced growth rate at lower temperature, a phenotype associated with defective expression of cyclophilins in other microorganisms. The B. abortus ΔcypAB mutant also displays reduced virulence in BALB/c mice and defective intracellular survival in HeLa cells. These findings suggest that cyclophilins are important for Brucella virulence and survival in the host cells.
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Bitoun JP, Liao S, Yao X, Xie GG, Wen ZT. The redox-sensing regulator Rex modulates central carbon metabolism, stress tolerance response and biofilm formation by Streptococcus mutans. PLoS One 2012; 7:e44766. [PMID: 23028612 PMCID: PMC3441419 DOI: 10.1371/journal.pone.0044766] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 08/06/2012] [Indexed: 01/15/2023] Open
Abstract
The Rex repressor has been implicated in regulation of central carbon and energy metabolism in gram-positive bacteria. We have previously shown that Streptococcus mutans, the primary causative agent of dental caries, alters its transcriptome upon Rex-deficiency and renders S. mutans to have increased susceptibility to oxidative stress, aberrations in glucan production, and poor biofilm formation. In this study, we showed that rex in S. mutans is co-transcribed as an operon with downstream guaA, encoding a putative glutamine amidotransferase. Electrophoretic mobility shift assays showed that recombinant Rex bound promoters of target genes avidly and specifically, including those down-regulated in response to Rex-deficiency, and that the ability of recombinant Rex to bind to selected promoters was modulated by NADH and NAD(+). Results suggest that Rex in S. mutans can function as an activator in response to intracellular NADH/NAD(+) level, although the exact binding site for activator Rex remains unclear. Consistent with a role in oxidative stress tolerance, hydrogen peroxide challenge assays showed that the Rex-deficient mutant, TW239, and the Rex/GuaA double mutant, JB314, were more susceptible to hydrogen peroxide killing than the wildtype, UA159. Relative to UA159, JB314 displayed major defects in biofilm formation, with a decrease of more than 50-fold in biomass after 48-hours. Collectively, these results further suggest that Rex in S. mutans regulates fermentation pathways, oxidative stress tolerance, and biofilm formation in response to intracellular NADH/NAD(+) level. Current effort is being directed to further investigation of the role of GuaA in S. mutans cellular physiology.
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Affiliation(s)
- Jacob P. Bitoun
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Sumei Liao
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Xin Yao
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Gary G. Xie
- Biology and Bioinformatics, Los Alamos National Laboratory, New Mexico, United States of America
| | - Zezhang T. Wen
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Microbiology, Immunology, and Parasitology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
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Ahn SJ, Qu MD, Roberts E, Burne RA, Rice KC. Identification of the Streptococcus mutans LytST two-component regulon reveals its contribution to oxidative stress tolerance. BMC Microbiol 2012; 12:187. [PMID: 22937869 PMCID: PMC3507848 DOI: 10.1186/1471-2180-12-187] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 08/21/2012] [Indexed: 02/07/2023] Open
Abstract
Background The S. mutans LrgA/B holin-like proteins have been shown to affect biofilm formation and oxidative stress tolerance, and are regulated by oxygenation, glucose levels, and by the LytST two-component system. In this study, we sought to determine if LytST was involved in regulating lrgAB expression in response to glucose and oxygenation in S. mutans. Results Real-time PCR revealed that growth phase-dependent regulation of lrgAB expression in response to glucose metabolism is mediated by LytST under low-oxygen conditions. However, the effect of LytST on lrgAB expression was less pronounced when cells were grown with aeration. RNA expression profiles in the wild-type and lytS mutant strains were compared using microarrays in early exponential and late exponential phase cells. The expression of 40 and 136 genes in early-exponential and late exponential phase, respectively, was altered in the lytS mutant. Although expression of comYB, encoding a DNA binding-uptake protein, was substantially increased in the lytS mutant, this did not translate to an effect on competence. However, a lrgA mutant displayed a substantial decrease in transformation efficiency, suggestive of a previously-unknown link between LrgA and S. mutans competence development. Finally, increased expression of genes encoding antioxidant and DNA recombination/repair enzymes was observed in the lytS mutant, suggesting that the mutant may be subjected to increased oxidative stress during normal growth. Although the intracellular levels of reaction oxygen species (ROS) appeared similar between wild-type and lytS mutant strains after overnight growth, challenge of these strains with hydrogen peroxide (H2O2) resulted in increased intracellular ROS in the lytS mutant. Conclusions Overall, these results: (1) Reinforce the importance of LytST in governing lrgAB expression in response to glucose and oxygen, (2) Define a new role for LytST in global gene regulation and resistance to H2O2, and (3) Uncover a potential link between LrgAB and competence development in S. mutans.
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Affiliation(s)
- Sang-Joon Ahn
- Department of Microbiology and Cell Science, College of Agricultural and Life Sciences, University of Florida, Gainesville, FL 32611, USA
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Hasan S, Danishuddin M, Adil M, Singh K, Verma PK, Khan AU. Efficacy of E. officinalis on the cariogenic properties of Streptococcus mutans: a novel and alternative approach to suppress quorum-sensing mechanism. PLoS One 2012; 7:e40319. [PMID: 22792279 PMCID: PMC3390397 DOI: 10.1371/journal.pone.0040319] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 06/04/2012] [Indexed: 11/18/2022] Open
Abstract
The present study was focused on evaluating the potential of Emblica officinalis against cariogenic properties of Streptococcus mutans, a causative microorganism for caries. The effect of crude extract and ethanolic fraction from Emblica officinalis fruit was analysed against S. mutans. The sub-MIC concentrations of crude and ethanolic fraction of E. officinalis were evaluated for its cariogenic properties such as acid production, biofilm formation, cell-surface hydrophobicity, glucan production, sucrose-dependent and independent adherence. Its effect on biofilm architecture was also investigated with the help of confocal and scanning electron microscopy (SEM). Moreover, expression of genes involved in biofilm formation was also studied by quantitative RT- PCR. This study showed 50% reduction in adherence at concentrations 156 µg/ and 312.5 µg/ml of crude extract and ethanolic fraction respectively. However, the biofilm was reduced to 50% in the presence of crude extract (39.04 µg/ml) and ethanolic fraction (78.08 µg/ml). Furthermore, effective reduction was observed in the glucan synthesis and cell surface hydrophobicity. The qRT-PCR revealed significant suppression of the genes involved in its virulence. Confocal and scanning electron microscopy clearly depicted the obliteration of biofilm structure with reference to control. Hence, this study reveals the potential of E. officinalis fruit extracts as an alternative and complementary medicine for dental caries by inhibiting the virulence factors of Streptococcus mutans.
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Affiliation(s)
- Sadaf Hasan
- Medical Microbiology and Molecular Biology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Mohd Danishuddin
- Medical Microbiology and Molecular Biology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Mohd Adil
- Medical Microbiology and Molecular Biology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Kunal Singh
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Praveen K. Verma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Asad U. Khan
- Medical Microbiology and Molecular Biology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
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Reactive oxygen species in the signaling and adaptation of multicellular microbial communities. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:976753. [PMID: 22829965 PMCID: PMC3395218 DOI: 10.1155/2012/976753] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 05/24/2012] [Indexed: 02/07/2023]
Abstract
One of the universal traits of microorganisms is their ability to form multicellular structures, the cells of which differentiate and communicate via various signaling molecules. Reactive oxygen species (ROS), and hydrogen peroxide in particular, have recently become well-established signaling molecules in higher eukaryotes, but still little is known about the regulatory functions of ROS in microbial structures. Here we summarize current knowledge on the possible roles of ROS during the development of colonies and biofilms, representatives of microbial multicellularity. In Saccharomyces cerevisiae colonies, ROS are predicted to participate in regulatory events involved in the induction of ammonia signaling and later on in programmed cell death in the colony center. While the latter process seems to be induced by the total ROS, the former event is likely to be regulated by ROS-homeostasis, possibly H2O2-homeostasis between the cytosol and mitochondria. In Candida albicans biofilms, the predicted signaling role of ROS is linked with quorum sensing molecule farnesol that significantly affects biofilm formation. In bacterial biofilms, ROS induce genetic variability, promote cell death in specific biofilm regions, and possibly regulate biofilm development. Thus, the number of examples suggesting ROS as signaling molecules and effectors in the development of microbial multicellularity is rapidly increasing.
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Xu X, Wang Y, Liao S, Wen ZT, Fan Y. Synthesis and characterization of antibacterial dental monomers and composites. J Biomed Mater Res B Appl Biomater 2012; 100:1151-62. [PMID: 22447582 DOI: 10.1002/jbm.b.32683] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 12/22/2011] [Accepted: 01/02/2012] [Indexed: 11/08/2022]
Abstract
The objective of this study is to synthesize antibacterial methacrylate and methacrylamide monomers and formulate antibacterial fluoride-releasing dental composites. Three antibacterial methacrylate or methacrylamide monomers containing long-chain quaternary ammonium fluoride, 1,2-methacrylamido-N,N,N-trimethyldodecan-1-aminium fluoride (monomer I), N-benzyl-11-(methacryloyloxy)-N,N-dimethylundecan-1-aminium fluoride (monomer II), and methacryloxyldecylpyridinium fluoride (monomer III) have been synthesized and analyzed by nuclear magnetic resonance (NMR) and mass spectrometry (MS). The cytotoxicity test and bactericidal test against Streptococcus mutans indicate that antibacterial monomer II is superior to monomers I and III. A series of dental composites containing 0-6% of antibacterial monomer II have been formulated and tested for degree of conversion (DC), flexure strength, water sorption, solubility, and inhibition of S. mutans biofilms. An antibacterial fluoride-releasing dental composite has also been formulated and tested for flexure strength and fluoride release. The dental composite containing 3% of monomer II has a significant effect against S. mutans biofilm formation without major adverse effects on its physical and mechanical properties. The new antibacterial monomers can be used together with the fluoride-releasing monomers containing a ternary zirconiun-fluoride chelate to formulate a new antibacterial fluoride-releasing dental composite. Such a new dental composite is expected to have higher anticaries efficacy and longer service life.
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Affiliation(s)
- Xiaoming Xu
- Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, School of Dentistry, New Orleans, Louisiana 70119, USA.
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50
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BrpA is involved in regulation of cell envelope stress responses in Streptococcus mutans. Appl Environ Microbiol 2012; 78:2914-22. [PMID: 22327589 DOI: 10.1128/aem.07823-11] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies have shown that BrpA plays a major role in acid and oxidative stress tolerance and biofilm formation by Streptococcus mutans. Mutant strains lacking BrpA also display increased autolysis and decreased viability, suggesting a role for BrpA in cell envelope integrity. In this study, we examined the impact of BrpA deficiency on cell envelope stresses induced by envelope-active antimicrobials. Compared to the wild-type strain UA159, the BrpA-deficient mutant (TW14D) was significantly more susceptible to antimicrobial agents, especially lipid II inhibitors. Several genes involved in peptidoglycan synthesis were identified by DNA microarray analysis as downregulated in TW14D. Luciferase reporter gene fusion assays also revealed that expression of brpA is regulated in response to environmental conditions and stresses induced by exposure to subinhibitory concentrations of cell envelope antimicrobials. In a Galleria mellonella (wax worm) model, BrpA deficiency was shown to diminish the virulence of S. mutans OMZ175, which, unlike S. mutans UA159, efficiently kills the worms. Collectively, these results suggest that BrpA plays a role in the regulation of cell envelope integrity and that deficiency of BrpA adversely affects the fitness and diminishes the virulence of OMZ175, a highly invasive strain of S. mutans.
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