Journal of Dental Research, Vol 72, 1032-1039, Copyright © 1993 by International & American Associations for Dental Research Online Journals

ARTICLES

Transformation efficiency of EMS-induced mutants of Streptococcus mutans of altered cell shape

L. Tao, T. J. MacAlister and J. M. Tanzer
Department of Oral Diagnosis, Schools of Dental Medicine and of Medicine, University of Connecticut Health Center, Farmington 06030.

Some Streptococcus mutans strains change shape from bacillary to coccal or ellipsoid form in response to the ratio of bicarbonate to potassium or of borate to potassium in growth media. So that insight into determinants of shape of these streptococci could be gained, and future genetic studies facilitated, the shapes of a series of transformable and nontransformable strains of S. mutans were studied and attempts made to isolate a mutant of augmented transformability. Several strains were mutagenized by ethylmethane sulfonate and mutants with altered colonial and cellular morphologies isolated. Cell shapes were studied by Gram stain and Nomarski interference microscopy, and by scanning and transmission electron microscopy. Diverse shape-altered mutants were isolated from seven transformable and two nontransformable strains of S. mutans. Among these, length-to-width ratios ranged from > 10 to about 0.25. Regulation of timing of cell division, septum formation, or septum completion events may have been altered in these mutants. While most mutants substantially or completely lost transformability, mutant LT11 had transformation efficiency of 1.3 x 10(-4) to 2.3 x 10(-3), more than two to three orders of magnitude greater than its parental UA159 and the well-known transformable strain GS5(HK), respectively. There was no evidence of production of competence factor by LT11. Competence of LT11 was maintained for at least six months upon storage at -70 degrees C, facilitating its use for genetic studies. While the morphologies of several shape-altered mutants were no longer responsive to changes of the bicarbonate/potassium, unlike those of their parentals, the morphology of LT11 persisted in its response to this condition.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				W.-C. Huang, Y.-Y. M. Chen, L.-J. Teng, H.-T. Lien, J.-Y. Chen, and J.-S. Chia Chromosomal inversion between rrn operons among Streptococcus mutans serotype c oral and blood isolates J. Med. Microbiol., February 1, 2008; 57(2): 198 - 206. [Abstract] [Full Text] [PDF]

				J. Merritt, L. Zheng, W. Shi, and F. Qi Genetic characterization of the hdrRM operon: a novel high-cell-density-responsive regulator in Streptococcus mutans Microbiology, August 1, 2007; 153(8): 2765 - 2773. [Abstract] [Full Text] [PDF]

				H. J. Busscher, B. van de Belt-Gritter, R. J. B. Dijkstra, W. Norde, F. C. Petersen, A. A. Scheie, and H. C. van der Mei Intermolecular Forces and Enthalpies in the Adhesion of Streptococcus mutans and an Antigen I/II-Deficient Mutant to Laminin Films J. Bacteriol., April 15, 2007; 189(8): 2988 - 2995. [Abstract] [Full Text] [PDF]

				J. C. Waterhouse and R. R. B. Russell Dispensable genes and foreign DNA in Streptococcus mutans Microbiology, June 1, 2006; 152(6): 1777 - 1788. [Abstract] [Full Text] [PDF]

				B. Wang and H. K. Kuramitsu Inducible Antisense RNA Expression in the Characterization of Gene Functions in Streptococcus mutans Infect. Immun., June 1, 2005; 73(6): 3568 - 3576. [Abstract] [Full Text] [PDF]

				C. Rathsam, R. E. Eaton, C. L. Simpson, G. V. Browne, T. Berg, D. W. S. Harty, and N. A. Jacques Up-regulation of competence- but not stress-responsive proteins accompanies an altered metabolic phenotype in Streptococcus mutans biofilms Microbiology, June 1, 2005; 151(6): 1823 - 1837. [Abstract] [Full Text] [PDF]

				A. C. L. Len, D. W. S. Harty, and N. A. Jacques Stress-responsive proteins are upregulated in Streptococcus mutans during acid tolerance Microbiology, May 1, 2004; 150(5): 1339 - 1351. [Abstract] [Full Text] [PDF]

				A. C. L. Len, D. W. S. Harty, and N. A. Jacques Proteome analysis of Streptococcus mutans metabolic phenotype during acid tolerance Microbiology, May 1, 2004; 150(5): 1353 - 1366. [Abstract] [Full Text] [PDF]

				L. Tao and J.M. Tanzer Novel Sucrose-dependent Adhesion Co-factors in Streptococcus mutans J. Dent. Res., July 1, 2002; 81(7): 505 - 510. [Abstract] [Full Text] [PDF]

				F. E. Martin, M. A. Nadkarni, N. A. Jacques, and N. Hunter Quantitative Microbiological Study of Human Carious Dentine by Culture and Real-Time PCR: Association of Anaerobes with Histopathological Changes in Chronic Pulpitis J. Clin. Microbiol., May 1, 2002; 40(5): 1698 - 1704. [Abstract] [Full Text] [PDF]

				F. C. Petersen, S. Assev, H. C. van der Mei, H. J. Busscher, and A. A. Scheie Functional Variation of the Antigen I/II Surface Protein in Streptococcus mutans and Streptococcus intermedius Infect. Immun., January 1, 2002; 70(1): 249 - 256. [Abstract] [Full Text] [PDF]

				M. A. Nadkarni, F. E. Martin, N. A. Jacques, and N. Hunter Determination of bacterial load by real-time PCR using a broad-range (universal) probe and primers set Microbiology, January 1, 2002; 148(1): 257 - 266. [Abstract] [Full Text] [PDF]

				Y.-H. Li, P. C. Y. Lau, J. H. Lee, R. P. Ellen, and D. G. Cvitkovitch Natural Genetic Transformation of Streptococcus mutans Growing in Biofilms J. Bacteriol., February 1, 2001; 183(3): 897 - 908. [Abstract] [Full Text]

				D. A. Boyd, D. G. Cvitkovitch, A. S. Bleiweis, M. Y. Kiriukhin, D. V. Debabov, F. C. Neuhaus, and I. R. Hamilton Defects in D-Alanyl-Lipoteichoic Acid Synthesis in Streptococcus mutans Results in Acid Sensitivity J. Bacteriol., November 1, 2000; 182(21): 6055 - 6065. [Abstract] [Full Text]

				D. A. Boyd, T. Thevenot, M. Gumbmann, A. L. Honeyman, and I. R. Hamilton Identification of the Operon for the Sorbitol (Glucitol) Phosphoenolpyruvate:Sugar Phosphotransferase System in Streptococcus mutans Infect. Immun., February 1, 2000; 68(2): 925 - 930. [Abstract] [Full Text] [PDF]

				G. Svensäter, B. Sjögreen, and I. R. Hamilton Multiple stress responses in Streptococcus mutans and the induction of general and stress-specific proteins Microbiology, January 1, 2000; 146(1): 107 - 117. [Abstract] [Full Text]

				D. K. Mercer, K. P. Scott, W. A. Bruce-Johnson, L. A. Glover, and H. J. Flint Fate of Free DNA and Transformation of the Oral Bacterium Streptococcus gordonii DL1 by Plasmid DNA in Human Saliva Appl. Envir. Microbiol., January 1, 1999; 65(1): 6 - 10. [Abstract] [Full Text]

				J. J. Ferretti Transcriptional Regulation of the Streptococcus mutans gal Operon by the GalR Repressor J. Bacteriol., November 1, 1998; 180(21): 5727 - 5732. [Abstract] [Full Text]

				C. L. Simpson and R. R. B. Russell Intracellular alpha -Amylase of Streptococcus mutans J. Bacteriol., September 1, 1998; 180(17): 4711 - 4717. [Abstract] [Full Text]

				C. L. Simpson and R. R. B. Russell Identification of a Homolog of CcpA Catabolite Repressor Protein in Streptococcus mutans Infect. Immun., May 1, 1998; 66(5): 2085 - 2092. [Abstract] [Full Text] [PDF]