1887

Abstract

In , autolysis is considered a programmed cell-death process executed principally by the major autolysin (LytA), and the underlying mechanism causing its activation is not completely understood. It is known that autolysis is triggered by competence development at alkaline pH and regulated by a two-component system, ComDE, which senses a competence-stimulating peptide (CSP) and behaves as a quorum-sensing mechanism. In this work, we found that acidic stress triggered a LytA-mediated autolysis and, curiously, this phenomenon was regulated by a CSP-independent ComE pathway. A further analysis of a hyperactive ComD mutant revealed that ComE needs to be phosphorylated to activate acidic stress-induced lysis (ASIL). The transcripts were induced by acidic culture conditions, suggesting that ComE could be sensing acidic stress. We also investigated CiaRH, a two-component system whose null mutants show a derepression and a CSP-dependent autolysis induction at alkaline pH. By analysis of double mutants, we demonstrated that CiaRH protected cells from ASIL by a ComE-independent pathway. Here, we propose that ComE is the principal route of the signalling pathway that determines a global stress response, and clearly regulates the induction of the LytA-mediated programmed cell death in . Acidic stress may represent for an alternative condition, in addition to competence and antibiotics, to assure the release of virulence factors, DNA and cell-wall compounds by autolysis, favouring genetic exchange and contributing to its pathogenesis.

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2008-05-01
2019-11-19
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References

  1. Andersen, N. E., Gyring, J., Hansen, A. J., Laursen, H. & Siesjo, B. K. ( 1989; ). Brain acidosis in experimental pneumococcal meningitis. J Cereb Blood Flow Metab 9, 381–387.[CrossRef]
    [Google Scholar]
  2. Bassoe, C. F. & Bjerknes, R. ( 1985; ). Phagocytosis by human leukocytes, phagosomal pH and degradation of seven species of bacteria measured by flow cytometry. J Med Microbiol 19, 115–125.[CrossRef]
    [Google Scholar]
  3. Chatellier, S. & Kotb, M. ( 2000; ). Preferential stimulation of human lymphocytes by oligodeoxynucleotides that copy DNA CpG motifs present in virulent genes of group A streptococci. Eur J Immunol 30, 993–1001.[CrossRef]
    [Google Scholar]
  4. Chen, J. D. & Morrison, D. A. ( 1987; ). Modulation of competence for genetic transformation in Streptococcus pneumoniae. J Gen Microbiol 133, 1959–1967.
    [Google Scholar]
  5. Claverys, J. P., Prudhomme, M. & Martin, B. ( 2006; ). Induction of competence regulons as a general response to stress in gram-positive bacteria. Annu Rev Microbiol 60, 451–475.[CrossRef]
    [Google Scholar]
  6. Cotter, P. D. & Hill, C. ( 2003; ). Surviving the acid test: responses of gram-positive bacteria to low pH. Microbiol Mol Biol Rev 67, 429–453.[CrossRef]
    [Google Scholar]
  7. Dagkessamanskaia, A., Moscoso, M., Henard, V., Guiral, S., Overweg, K., Reuter, M., Martin, B., Wells, J. & Claverys, J. P. ( 2004; ). Interconnection of competence, stress and CiaR regulons in Streptococcus pneumoniae: competence triggers stationary phase autolysis of ciaR mutant cells. Mol Microbiol 51, 1071–1086.[CrossRef]
    [Google Scholar]
  8. Echenique, J. R. & Trombe, M. C. ( 2001; ). Competence repression under oxygen limitation through the two-component MicAB signal-transducing system in Streptococcus pneumoniae and involvement of the PAS domain of MicB. J Bacteriol 183, 4599–4608.[CrossRef]
    [Google Scholar]
  9. Echenique, J. R., Chapuy-Regaud, S. & Trombe, M. C. ( 2000; ). Competence regulation by oxygen in Streptococcus pneumoniae: involvement of ciaRH and comCDE. Mol Microbiol 36, 688–696.
    [Google Scholar]
  10. Guiral, S., Mitchell, T. J., Martin, B. & Claverys, J. P. ( 2005; ). Competence-programmed predation of noncompetent cells in the human pathogen Streptococcus pneumoniae: genetic requirements. Proc Natl Acad Sci U S A 102, 8710–8715.[CrossRef]
    [Google Scholar]
  11. Havarstein, L. S., Martin, B., Johnsborg, O., Granadel, C. & Claverys, J. P. ( 2006; ). New insights into the pneumococcal fratricide: relationship to clumping and identification of a novel immunity factor. Mol Microbiol 59, 1297–1307.[CrossRef]
    [Google Scholar]
  12. Hui, F. M., Zhou, L. & Morrison, D. A. ( 1995; ). Competence for genetic transformation in Streptococcus pneumoniae: organization of a regulatory locus with homology to two lactococcin A secretion genes. Gene 153, 25–31.[CrossRef]
    [Google Scholar]
  13. Lacks, S. A. & Greenberg, B. ( 2001; ). Constitutive competence for genetic transformation in Streptococcus pneumoniae caused by mutation of a transmembrane histidine kinase. Mol Microbiol 42, 1035–1045.[CrossRef]
    [Google Scholar]
  14. Lau, P. C., Sung, C. K., Lee, J. H., Morrison, D. A. & Cvitkovitch, D. G. ( 2002; ). PCR ligation mutagenesis in transformable streptococci: application and efficiency. J Microbiol Methods 49, 193–205.[CrossRef]
    [Google Scholar]
  15. Lee, M. S. & Morrison, D. A. ( 1999; ). Identification of a new regulator in Streptococcus pneumoniae linking quorum sensing to competence for genetic transformation. J Bacteriol 181, 5004–5016.
    [Google Scholar]
  16. Lewis, K. ( 2000; ). Programmed death in bacteria. Microbiol Mol Biol Rev 64, 503–514.[CrossRef]
    [Google Scholar]
  17. Li, Y. H., Hanna, M. N., Svensäter, G., Ellen, R. P. & Cvitkovitch, D. G. ( 2001; ). Cell density modulates acid adaptation in Streptococcus mutans: implications for survival in biofilms. J Bacteriol 183, 6875–6884.[CrossRef]
    [Google Scholar]
  18. Light, R. W., Girard, W. M., Jenkinson, S. G. & George, R. B. ( 1980; ). Parapneumonic effusions. Am J Med 69, 507–512.[CrossRef]
    [Google Scholar]
  19. Lindahl, T. & Nyberg, B. ( 1972; ). Rate of depurination of native deoxyribonucleic acid. Biochemistry 11, 3610–3618.[CrossRef]
    [Google Scholar]
  20. Livak, K. J. & Schmittgen, T. D. ( 2001; ). Analysis of relative gene expression data using real-time quantitative PCR and the 2–ΔΔC(T) method. Methods 25, 402–408.[CrossRef]
    [Google Scholar]
  21. Luo, P., Li, H. & Morrison, D. A. ( 2003; ). ComX is a unique link between multiple quorum sensing outputs and competence in Streptococcus pneumoniae. Mol Microbiol 50, 623–633.[CrossRef]
    [Google Scholar]
  22. Martin, B., Prudhomme, M., Alloing, G., Granadel, C. & Claverys, J. P. ( 2000; ). Cross-regulation of competence pheromone production and export in the early control of transformation in Streptococcus pneumoniae. Mol Microbiol 38, 867–878.[CrossRef]
    [Google Scholar]
  23. Martin-Galiano, A. J., Overweg, K., Ferrandiz, M. J., Reuter, M., Wells, J. M. & de la Campa, A. G. ( 2005; ). Transcriptional analysis of the acid tolerance response in Streptococcus pneumoniae. Microbiology 151, 3935–3946.[CrossRef]
    [Google Scholar]
  24. Mascher, T., Zahner, D., Merai, M., Balmelle, N., de Saizieu, A. B. & Hakenbeck, R. ( 2003; ). The Streptococcus pneumoniae cia regulon: CiaR target sites and transcription profile analysis. J Bacteriol 185, 60–70.[CrossRef]
    [Google Scholar]
  25. Mascher, T., Heintz, M., Zähner, D., Merai, M. & Hakenbeck, R. ( 2006; ). The CiaRH system of Streptococcus pneumoniae prevents lysis during stress induced by treatment with cell wall inhibitors and by mutations in pbp2x involved in beta-lactam resistance. J Bacteriol 188, 1959–1968.[CrossRef]
    [Google Scholar]
  26. McDaniel, L. S., Yother, J., Vijayakumar, M., McGarry, L., Guild, W. R. & Briles, D. E. ( 1987; ). Use of insertional inactivation to facilitate studies of biological properties of pneumococcal surface protein A (PspA). J Exp Med 165, 381–394.[CrossRef]
    [Google Scholar]
  27. Morrison, D. A., Lacks, S. A., Guild, W. R. & Hageman, J. M. ( 1983; ). Isolation and characterization of three new classes of transformation-deficient mutants of Streptococcus pneumoniae that are defective in DNA transport and genetic recombination. J Bacteriol 156, 281–290.
    [Google Scholar]
  28. Mortier-Barriere, I., de Saizieu, A., Claverys, J. P. & Martin, B. ( 1998; ). Competence-specific induction of recA is required for full recombination proficiency during transformation in Streptococcus pneumoniae. Mol Microbiol 27, 159–170.[CrossRef]
    [Google Scholar]
  29. Moscoso, M. & Claverys, J. P. ( 2004; ). Release of DNA into the medium by competent Streptococcus pneumoniae: kinetics, mechanism and stability of the liberated DNA. Mol Microbiol 54, 783–794.[CrossRef]
    [Google Scholar]
  30. Nau, R. & Eiffert, H. ( 2002; ). Modulation of release of proinflammatory bacterial compounds by antibacterials: potential impact on course of inflammation and outcome in sepsis and meningitis. Clin Microbiol Rev 15, 95–110.[CrossRef]
    [Google Scholar]
  31. Oggioni, M. R., Iannelli, F., Ricci, S., Chiavolini, D., Parigi, R., Trappetti, C., Claverys, J. P. & Pozzi, G. ( 2004; ). Antibacterial activity of a competence-stimulating peptide in experimental sepsis caused by Streptococcus pneumoniae. Antimicrob Agents Chemother 48, 4725–4732.[CrossRef]
    [Google Scholar]
  32. Pestova, E. V., Havarstein, L. S. & Morrison, D. A. ( 1996; ). Regulation of competence for genetic transformation in Streptococcus pneumoniae by an auto-induced peptide pheromone and a two-component regulatory system. Mol Microbiol 21, 853–862.[CrossRef]
    [Google Scholar]
  33. Peterson, S. N., Sung, C. K., Cline, R., Desai, B. V., Snesrud, E. C., Luo, P., Walling, J., Li, H., Mintz, M. & other authors ( 2004; ). Identification of competence pheromone responsive genes in Streptococcus pneumoniae by use of DNA microarrays. Mol Microbiol 51, 1051–1070.[CrossRef]
    [Google Scholar]
  34. Prudhomme, M., Attaiech, L., Sanchez, G., Martin, B. & Claverys, J. P. ( 2006; ). Antibiotic stress induces genetic transformability in the human pathogen Streptococcus pneumoniae. Science 313, 89–92.[CrossRef]
    [Google Scholar]
  35. Sanchez-Puelles, J. M., Ronda, C., Garcia, J. L., Garcia, P., Lopez, R. & Garcia, E. ( 1986; ). Searching for autolysin functions. Characterization of a pneumococcal mutant deleted in the lytA gene. Eur J Biochem 158, 289–293.[CrossRef]
    [Google Scholar]
  36. Sebert, M. E., Palmer, L. M., Rosenberg, M. & Weiser, J. N. ( 2002; ). Microarray-based identification of htrA, a Streptococcus pneumoniae gene that is regulated by the CiaRH two-component system and contributes to nasopharyngeal colonization. Infect Immun 70, 4059–4067.[CrossRef]
    [Google Scholar]
  37. Steinmoen, H., Knutsen, E. & Havarstein, L. S. ( 2002; ). Induction of natural competence in Streptococcus pneumoniae triggers lysis and DNA release from a subfraction of the cell population. Proc Natl Acad Sci U S A 99, 7681–7686.[CrossRef]
    [Google Scholar]
  38. Steinmoen, H., Teigen, A. & Havarstein, L. S. ( 2003; ). Competence-induced cells of Streptococcus pneumoniae lyse competence-deficient cells of the same strain during cocultivation. J Bacteriol 185, 7176–7183.[CrossRef]
    [Google Scholar]
  39. Tomasz, A. & Mosser, J. L. ( 1966; ). On the nature of the pneumococcal activator substance. Proc Natl Acad Sci U S A 55, 58–66.[CrossRef]
    [Google Scholar]
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Bacterial strains and plasmids used in this work. [ PDF] (73 kb) Primers used in this work. [ PDF] (18 kb) Kinetics of transcripts in response to acidic stress. The transcription level was measured in cells exposed to pH 5.9. Strains RC852 ( ), RC820 ( ) and RC862 ( ) were grown in ABM/pH 7.8 to mid-exponential phase and resuspended in ABM/pH 5.9 and RNA was extracted at 0 min, 10 min and 30 min. Fold change in gene expression was measured by quantitative real-time RT-PCR and was calculated using the 2 method. The gene was used as the internal control and the reference condition was time 0 min of strain RC852. Error bars indicate the standard deviation of the mean. [ PDF] (58 kb)

PDF

Bacterial strains and plasmids used in this work. [ PDF] (73 kb) Primers used in this work. [ PDF] (18 kb) Kinetics of transcripts in response to acidic stress. The transcription level was measured in cells exposed to pH 5.9. Strains RC852 ( ), RC820 ( ) and RC862 ( ) were grown in ABM/pH 7.8 to mid-exponential phase and resuspended in ABM/pH 5.9 and RNA was extracted at 0 min, 10 min and 30 min. Fold change in gene expression was measured by quantitative real-time RT-PCR and was calculated using the 2 method. The gene was used as the internal control and the reference condition was time 0 min of strain RC852. Error bars indicate the standard deviation of the mean. [ PDF] (58 kb)

PDF

Bacterial strains and plasmids used in this work. [ PDF] (73 kb) Primers used in this work. [ PDF] (18 kb) Kinetics of transcripts in response to acidic stress. The transcription level was measured in cells exposed to pH 5.9. Strains RC852 ( ), RC820 ( ) and RC862 ( ) were grown in ABM/pH 7.8 to mid-exponential phase and resuspended in ABM/pH 5.9 and RNA was extracted at 0 min, 10 min and 30 min. Fold change in gene expression was measured by quantitative real-time RT-PCR and was calculated using the 2 method. The gene was used as the internal control and the reference condition was time 0 min of strain RC852. Error bars indicate the standard deviation of the mean. [ PDF] (58 kb)

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