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Böttcher B, Kienast SD, Leufken J, Eggers C, Sharma P, Leufken CM, Morgner B, Drexler HCA, Schulz D, Allert S, Jacobsen ID, Vylkova S, Leidel SA, Brunke S. A highly conserved tRNA modification contributes to C. albicans filamentation and virulence. Microbiol Spectr 2024; 12:e0425522. [PMID: 38587411 PMCID: PMC11064501 DOI: 10.1128/spectrum.04255-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/18/2024] [Indexed: 04/09/2024] Open
Abstract
tRNA modifications play important roles in maintaining translation accuracy in all domains of life. Disruptions in the tRNA modification machinery, especially of the anticodon stem loop, can be lethal for many bacteria and lead to a broad range of phenotypes in baker's yeast. Very little is known about the function of tRNA modifications in host-pathogen interactions, where rapidly changing environments and stresses require fast adaptations. We found that two closely related fungal pathogens of humans, the highly pathogenic Candida albicans and its much less pathogenic sister species, Candida dubliniensis, differ in the function of a tRNA-modifying enzyme. This enzyme, Hma1, exhibits species-specific effects on the ability of the two fungi to grow in the hypha morphology, which is central to their virulence potential. We show that Hma1 has tRNA-threonylcarbamoyladenosine dehydratase activity, and its deletion alters ribosome occupancy, especially at 37°C-the body temperature of the human host. A C. albicans HMA1 deletion mutant also shows defects in adhesion to and invasion into human epithelial cells and shows reduced virulence in a fungal infection model. This links tRNA modifications to host-induced filamentation and virulence of one of the most important fungal pathogens of humans.IMPORTANCEFungal infections are on the rise worldwide, and their global burden on human life and health is frequently underestimated. Among them, the human commensal and opportunistic pathogen, Candida albicans, is one of the major causative agents of severe infections. Its virulence is closely linked to its ability to change morphologies from yeasts to hyphae. Here, this ability is linked-to our knowledge for the first time-to modifications of tRNA and translational efficiency. One tRNA-modifying enzyme, Hma1, plays a specific role in C. albicans and its ability to invade the host. This adds a so-far unknown layer of regulation to the fungal virulence program and offers new potential therapeutic targets to fight fungal infections.
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Affiliation(s)
- Bettina Böttcher
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sandra D. Kienast
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Johannes Leufken
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Cristian Eggers
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Puneet Sharma
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Christine M. Leufken
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Bianka Morgner
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Hannes C. A. Drexler
- Bioanalytical Mass Spectrometry Unit, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Daniela Schulz
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Stefanie Allert
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Ilse D. Jacobsen
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Slavena Vylkova
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sebastian A. Leidel
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
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Lyu Z, Wilson C, Ling J. Translational Fidelity during Bacterial Stresses and Host Interactions. Pathogens 2023; 12:383. [PMID: 36986305 PMCID: PMC10057733 DOI: 10.3390/pathogens12030383] [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: 01/25/2023] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 03/05/2023] Open
Abstract
Translational fidelity refers to accuracy during protein synthesis and is maintained in all three domains of life. Translational errors occur at base levels during normal conditions and may rise due to mutations or stress conditions. In this article, we review our current understanding of how translational fidelity is perturbed by various environmental stresses that bacterial pathogens encounter during host interactions. We discuss how oxidative stress, metabolic stresses, and antibiotics affect various types of translational errors and the resulting effects on stress adaption and fitness. We also discuss the roles of translational fidelity during pathogen-host interactions and the underlying mechanisms. Many of the studies covered in this review will be based on work with Salmonella enterica and Escherichia coli, but other bacterial pathogens will also be discussed.
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Affiliation(s)
| | | | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
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Mannheimia haemolytica biofilm formation on bovine respiratory epithelial cells. Vet Microbiol 2016; 197:129-136. [PMID: 27938674 PMCID: PMC7126505 DOI: 10.1016/j.vetmic.2016.11.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/07/2016] [Accepted: 11/07/2016] [Indexed: 11/22/2022]
Abstract
We devise a novel system that allows M. haemolytica biofilms to form on epithelial cells. Mucin significantly decreased biofilm formation. Prior infection with several respiratory viruses does not alter biofilm formation. Biofilms on epithelial cells were more resistant to some antibiotics than biofilms on polystyrene.
Mannheimia haemolytica is the most important bacterial agent associated with the bovine respiratory disease complex (BRDC), which causes worldwide economic losses to the cattle industry. M. haemolytica cells initially colonize the tonsillar crypts in the upper respiratory tract of cattle, from where they can subsequently descend into the lungs to cause disease. Many bacteria exist as biofilms inside their hosts. We hypothesize that M. haemolytica colonization of cattle during its commensal state may include biofilm formation. To begin to assess this possibility, we developed an in vitro system to study biofilm formation directly on bovine respiratory epithelial cells. Using fixed primary bovine bronchial epithelial cells, we observed M. haemolytica biofilm formation after a 48 h incubation period at 37 °C. Addition of mucin, the main component of mucus present in the upper respiratory tract, decreased M. haemolytica biofilm formation on bovine epithelial cells. We investigated the effects of prior viral infection of the epithelial cells on subsequent biofilm formation by M. haemolytica and found negligible effects. Utilization of this model system will provide new insights into the potential role of biofilm formation by M. haemolytica in the pathogenesis of BRDC.
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Matsubayashi M, Kawahara F, Hatta T, Yamagishi J, Miyoshi T, Anisuzzaman, Sasai K, Isobe T, Kita K, Tsuji N. Transcriptional profiles of virulent and precocious strains of Eimeria tenella at sporozoite stage; novel biological insight into attenuated asexual development. INFECTION GENETICS AND EVOLUTION 2016; 40:54-62. [DOI: 10.1016/j.meegid.2016.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 02/17/2016] [Accepted: 02/19/2016] [Indexed: 10/22/2022]
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Gao T, Tan M, Liu W, Zhang C, Zhang T, Zheng L, Zhu J, Li L, Zhou R. GidA, a tRNA Modification Enzyme, Contributes to the Growth, and Virulence of Streptococcus suis Serotype 2. Front Cell Infect Microbiol 2016; 6:44. [PMID: 27148493 PMCID: PMC4835480 DOI: 10.3389/fcimb.2016.00044] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/27/2016] [Indexed: 11/16/2022] Open
Abstract
Glucose-inhibited division protein (GidA), is a tRNA modification enzyme functioning together with MnmE in the addition of a carboxymethylaminomethyl group to position 5 of the anticodon wobble uridine of tRNA. Here, we report a GidA homolog from a Chinese isolate SC-19 of the zoonotic Streptococcus suis serotype 2 (SS2). gidA disruption led to a defective growth, increased capsule thickness, and reduced hemolytic activity. Moreover, the gidA deletion mutant (ΔgidA) displayed reduced mortality and bacterial loads in mice, reduced ability of adhesion to and invasion in epithelial cells, and increased sensitivity to phagocytosis. The iTRAQ analysis identified 372 differentially expressed (182 up- and 190 down-regulated) proteins in ΔgidA and SC-19. Numerous DNA replication, cell division, and virulence associated proteins were downregulated, whereas many capsule synthesis enzymes were upregulated by gidA disruption. This is consistent with the phenotypes of the mutant. Thus, GidA is a translational regulator that plays an important role in the growth, cell division, capsule biosynthesis, and virulence of SS2. Our findings provide new insight into the regulatory function of GidA in bacterial pathogens.
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Affiliation(s)
- Ting Gao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China; Veterinary Medicine Laboratory, Institute of Animal Husbandry and Veterinary Science, Hubei Academy of Agricultural ScienceWuhan, China; Wuhan Chopper Biology Co., Ltd.Wuhan, China
| | - Meifang Tan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Wanquan Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Chunyan Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Tengfei Zhang
- Veterinary Medicine Laboratory, Institute of Animal Husbandry and Veterinary Science, Hubei Academy of Agricultural Science Wuhan, China
| | - Linlin Zheng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Jiawen Zhu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Lu Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China; Cooperative Innovation Center of Sustainable Pig ProductionWuhan, China
| | - Rui Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China; Cooperative Innovation Center of Sustainable Pig ProductionWuhan, China
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Ardissone S, Viollier PH. Interplay between flagellation and cell cycle control in Caulobacter. Curr Opin Microbiol 2015; 28:83-92. [PMID: 26476805 DOI: 10.1016/j.mib.2015.08.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 08/09/2015] [Accepted: 08/11/2015] [Indexed: 12/21/2022]
Abstract
The assembly of the flagellum, a sophisticated nanomachine powering bacterial locomotion in liquids and across surfaces, is highly regulated. In the synchronizable α-Proteobacterium Caulobacter crescentus, the flagellum is built at a pre-selected cell pole and flagellar transcript abundance oscillates during the cell cycle. Conserved regulators not only dictate when the transcripts encoding flagellar structural proteins peak, but also those encoding polarization factors. Additionally, post-transcriptional cell cycle cues facilitate flagellar (dis-)assembly at the new cell pole. Because of this regulatory complexity and the power of bacterial genetics, motility is a suitable and simple proxy for dissecting how bacteria implement cell cycle progression and polarity, while also providing clues on how bacteria might decide when and where to display other surface structures.
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Affiliation(s)
- Silvia Ardissone
- Department of Microbiology and Molecular Medicine, Institute of Genetics and Genomics in Geneva (iGE3), Faculty of Medicine, University of Geneva, Rue Michel Servet 1, 1211 Geneva 4, Switzerland
| | - Patrick H Viollier
- Department of Microbiology and Molecular Medicine, Institute of Genetics and Genomics in Geneva (iGE3), Faculty of Medicine, University of Geneva, Rue Michel Servet 1, 1211 Geneva 4, Switzerland.
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Shippy DC, Fadl AA. RNA modification enzymes encoded by the gid operon: Implications in biology and virulence of bacteria. Microb Pathog 2015; 89:100-7. [PMID: 26427881 DOI: 10.1016/j.micpath.2015.09.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/23/2015] [Indexed: 01/10/2023]
Abstract
Ribonucleic acid (RNA) molecules consist of numerous chemically modified nucleosides that are highly conserved in eukarya, archeae, and bacteria, while others are unique to each domain of life. In bacteria, hundreds of RNA modification enzymes have been identified and implicated in biological pathways associated with many cell processes. The glucose-inhibited division (gid) operon encodes genes for two RNA modification enzymes named GidA and GidB. Studies have shown GidA is essential for the proper biosynthesis of 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U) of bacterial transfer RNA (tRNA) with GidB responsible for the methylation of the 16S ribosomal RNA (rRNA). Furthermore, deletion of gidA and gidB has shown to alter numerous bacterial properties like virulence, stress response, morphology, growth, antibiotic susceptibility, and others. In this review, we discuss the present knowledge of the RNA modification enzymes GidA and GidB, and their potential role in the biology and virulence of bacteria.
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Affiliation(s)
- Daniel C Shippy
- Department of Animal Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Amin A Fadl
- Department of Animal Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Lies M, Visser BJ, Joshi MC, Magnan D, Bates D. MioC and GidA proteins promote cell division in E. coli. Front Microbiol 2015; 6:516. [PMID: 26074904 PMCID: PMC4446571 DOI: 10.3389/fmicb.2015.00516] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/09/2015] [Indexed: 11/24/2022] Open
Abstract
The well-conserved genes surrounding the E. coli replication origin, mioC and gidA, do not normally affect chromosome replication and have little known function. We report that mioC and gidA mutants exhibit a moderate cell division inhibition phenotype. Cell elongation is exacerbated by a fis deletion, likely owing to delayed replication and subsequent cell cycle stress. Measurements of replication initiation frequency and origin segregation indicate that mioC and gidA do not inhibit cell division through any effect on oriC function. Division inhibition is also independent of the two known replication/cell division checkpoints, SOS and nucleoid occlusion. Complementation analysis indicates that mioC and gidA affect cell division in trans, indicating their effect is at the protein level. Transcriptome analysis by RNA sequencing showed that expression of a cell division septum component, YmgF, is significantly altered in mioC and gidA mutants. Our data reveal new roles for the gene products of gidA and mioC in the division apparatus, and we propose that their expression, cyclically regulated by chromatin remodeling at oriC, is part of a cell cycle regulatory program coordinating replication initiation and cell division.
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Affiliation(s)
- Mark Lies
- Molecular and Human Genetics, Baylor College of Medicine Houston, TX, USA
| | - Bryan J Visser
- Integrative Molecular and Biomedical Sciences, Baylor College of Medicine Houston, TX, USA
| | - Mohan C Joshi
- Molecular and Human Genetics, Baylor College of Medicine Houston, TX, USA
| | - David Magnan
- Integrative Molecular and Biomedical Sciences, Baylor College of Medicine Houston, TX, USA
| | - David Bates
- Molecular and Human Genetics, Baylor College of Medicine Houston, TX, USA ; Integrative Molecular and Biomedical Sciences, Baylor College of Medicine Houston, TX, USA
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tRNA modification enzymes GidA and MnmE: potential role in virulence of bacterial pathogens. Int J Mol Sci 2014; 15:18267-80. [PMID: 25310651 PMCID: PMC4227215 DOI: 10.3390/ijms151018267] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/02/2014] [Accepted: 10/08/2014] [Indexed: 01/02/2023] Open
Abstract
Transfer RNA (tRNA) is an RNA molecule that carries amino acids to the ribosomes for protein synthesis. These tRNAs function at the peptidyl (P) and aminoacyl (A) binding sites of the ribosome during translation, with each codon being recognized by a specific tRNA. Due to this specificity, tRNA modification is essential for translational efficiency. Many enzymes have been implicated in the modification of bacterial tRNAs, and these enzymes may complex with one another or interact individually with the tRNA. Approximately, 100 tRNA modification enzymes have been identified with glucose-inhibited division (GidA) protein and MnmE being two of the enzymes studied. In Escherichia coli and Salmonella, GidA and MnmE bind together to form a functional complex responsible for the proper biosynthesis of 5-methylaminomethyl-2-thiouridine (mnm5s2U34) of tRNAs. Studies have implicated this pathway in a major pathogenic regulatory mechanism as deletion of gidA and/or mnmE has attenuated several bacterial pathogens like Salmonella enterica serovar Typhimurium, Pseudomonas syringae, Aeromonas hydrophila, and many others. In this review, we summarize the potential role of the GidA/MnmE tRNA modification pathway in bacterial virulence, interactions with the host, and potential therapeutic strategies resulting from a greater understanding of this regulatory mechanism.
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Nagarajan S, Srivastava S, Sherman LA. Essential role of the plasmid hik31 operon in regulating central metabolism in the dark in Synechocystis sp. PCC 6803. Mol Microbiol 2013; 91:79-97. [PMID: 24237382 DOI: 10.1111/mmi.12442] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2013] [Indexed: 12/13/2022]
Abstract
The plasmid hik31 operon (P3, slr6039-slr6041) is located on the pSYSX plasmid in Synechocystis sp. PCC 6803. A P3 mutant (ΔP3) had a growth defect in the dark and a pigment defect that was worsened by the addition of glucose. The glucose defect was from incomplete metabolism of the substrate, was pH dependent, and completely overcome by the addition of bicarbonate. Addition of organic carbon and nitrogen sources partly alleviated the defects of the mutant in the dark. Electron micrographs of the mutant revealed larger cells with division defects, glycogen limitation, lack of carboxysomes, deteriorated thylakoids and accumulation of polyhydroxybutyrate and cyanophycin. A microarray experiment over two days of growth in light-dark plus glucose revealed downregulation of several photosynthesis, amino acid biosynthesis, energy metabolism genes; and an upregulation of cell envelope and transport and binding genes in the mutant. ΔP3 had an imbalance in carbon and nitrogen levels and many sugar catabolic and cell division genes were negatively affected after the first dark period. The mutant suffered from oxidative and osmotic stress, macronutrient limitation, and an energy deficit. Therefore, the P3 operon is an important regulator of central metabolism and cell division in the dark.
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Affiliation(s)
- Sowmya Nagarajan
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
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GidA Expression in Salmonella is Modulated Under Certain Environmental Conditions. Curr Microbiol 2013; 67:279-85. [DOI: 10.1007/s00284-013-0361-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 02/26/2013] [Indexed: 01/03/2023]
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Shippy DC, Eakley NM, Lauhon CT, Bochsler PN, Fadl AA. Virulence characteristics of Salmonella following deletion of genes encoding the tRNA modification enzymes GidA and MnmE. Microb Pathog 2013; 57:1-9. [DOI: 10.1016/j.micpath.2013.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Revised: 01/11/2013] [Accepted: 01/14/2013] [Indexed: 12/25/2022]
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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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Shippy DC, Fadl AA. Immunological characterization of a gidA mutant strain of Salmonella for potential use in a live-attenuated vaccine. BMC Microbiol 2012. [PMID: 23194372 PMCID: PMC3520829 DOI: 10.1186/1471-2180-12-286] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background Salmonella is often associated with gastrointestinal disease outbreaks in humans throughout the world due to the consumption of contaminated food. Our previous studies have shown that deletion of glucose-inhibited division gene (gidA) significantly attenuated Salmonella enterica serovar Typhimurium (STM) virulence in both in vitro and in vivo models of infection. Most importantly, immunization with the gidA mutant protected mice from a lethal dose challenge of wild-type STM. In this study, we further characterize the gidA mutant STM strain for potential use in a live-attenuated vaccine. Results The protective efficacy of immunization with the gidA mutant was evaluated by challenging immunized mice with a lethal dose of wild-type STM. Sera levels of IgG2a and IgG1, passive transfer of sera and cells, and cytokine profiling were performed to study the induction of humoral and cellular immune responses induced by immunization with the gidA mutant strain. Additionally, a lymphocyte proliferation assay was performed to gauge the splenocyte survival in response to treatment with STM cell lysate. Mice immunized with the gidA mutant strain were fully protected from a lethal dose challenge of wild-type STM. Naïve mice receiving either cells or sera from immunized mice were partially protected from a lethal dose challenge of wild-type STM. The lymphocyte proliferation assay displayed a significant response of splenocytes from immunized mice when compared to splenocytes from non-immunized control mice. Furthermore, the immunized mice displayed significantly higher levels of IgG1 and IgG2a with a marked increase in IgG1. Additionally, immunization with the gidA mutant strain evoked higher levels of IL-2, IFN-γ, and IL-10 cytokines in splenocytes induced with STM cell lysate. Conclusions Together, the results demonstrate that immunization with the gidA mutant strain protects mice by inducing humoral and cellular immune responses with the humoral immune response potentially being the main mechanism of protection.
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Affiliation(s)
- Daniel C Shippy
- Department of Animal Sciences, University of Wisconsin-Madison, 1675 Observatory Dr, Madison, WI 53706, USA
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