Transformation Efficiency of EMS-induced Mutants of Streptococcus mutans of Altered Cell Shape

Lin, Tao; MacAlister, T J; Tanzer, Jason M.

doi:10.1177/00220345930720060701

Cited by 57 publications

(44 citation statements)

References 29 publications

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“…For example, stocks of Ingbritt and GS5 held in different laboratories display variation in properties (Ellwood et al, 1976;Gibbons et al, 1966;Tao et al, 1993) and there are reports of changes during multiple laboratory subcultures (Cvitkovitch & Hamilton, 1994;McBride et al, 1984;Russell & Smith, 1986).This study provides two examples where consequential genetic changes may have been precipitated by laboratory manipulation. Strain LT11, which was derived by chemical mutagenesis of UA159 (Tao et al, 1993), has lost TnSmu2 and the IS3 elements detected in its parent UA159 (Table 1). Similarly, V1996, a mutant of V403 in which gtf and ftf genes have been knocked out by allelic exchange (Munro et al, 1991), has also undergone further change.…”

Section: Discussionmentioning

confidence: 76%

Dispensable genes and foreign DNA in Streptococcus mutans

Waterhouse¹,

Russell²

2006

Microbiology

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A range of properties, including the ability to utilize various sugars, bind macromolecules and produce mutacins, are known to vary in their occurrence in different strains of Streptococcus mutans. In addition, insertion-sequence elements show a limited distribution and sequencing of the genome of S. mutans UA159 has revealed the presence of putative genomic islands of atypical base composition indicative of foreign DNA. PCR primers flanking regions suspected of having inserted DNA were designed on the basis of the genome sequence of S. mutans UA159 and used to explore variation in a collection of 39 strains isolated in various parts of the world over the last 40 years. Extensive differences between strains were detected, and similar insertion/deletion events appear to be present in the genomes of strains with very different origins. In two instances, insertion of foreign DNA appears to have displaced original S. mutans genes. Together with previous results on the occurrence of deletions in genes associated with sugar metabolism, the results indicate that S. mutans has a core genome and a dispensable genome, and that dispensable genes have become widely distributed through horizontal transfer.

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Section: Discussionmentioning

confidence: 76%

Dispensable genes and foreign DNA in Streptococcus mutans

Waterhouse¹,

Russell²

2006

Microbiology

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“…While there are numerous examples of mutations that lower the natural competence ability of S. mutans (Abranches et al, 2006;Ahn et al, 2005;Hussain et al, 2006;Merritt et al, 2005c;Qi et al, 2004;Rolerson et al, 2006;Senadheera et al, 2005Senadheera et al, , 2007Wang & Kuramitsu, 2006;Wen et al, 2005), to our knowledge, there is only one other report of a mutation that increases natural competence (Tao et al, 1993). This mutation was generated by chemical mutagenesis and its identity has, so far, not been published.…”

Section: Discussionmentioning

confidence: 99%

Genetic characterization of the hdrRM operon: a novel high-cell-density-responsive regulator in Streptococcus mutans

et al. 2007

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Many species of bacteria can adhere to surfaces and grow as sessile communities. The continued accumulation of bacteria can eventually lead to the extremely high-cell-density environment characteristic of many biofilms or cell colonies. This is the normal habitat of the cariogenic species Streptococcus mutans, which normally resides in the high-cell-density, multispecies community commonly referred to as dental plaque. Previous work has demonstrated that the transcription of two separate bacteriocins can be activated by the high-cell-density conditions created through the centrifugation and incubation of cell pellets. In this study, we identified an uncharacterized two-gene operon that was induced .10-fold by conditions of high cell density. The genes of the operon encode a putative transcription regulator and a membrane protein, which were renamed as hdrR and hdrM, respectively. A transcription fusion to the hdrRM operon confirmed its induction by high cell density. Mutation of hdrM abolished bacteriocin production, greatly increased natural competence, reduced the growth rate, and severely affected biofilm formation. Interestingly, no obvious phenotypes were observed from a non-polar mutation of hdrR or mutations affecting the entire operon. These data suggest that the hdrRM operon may constitute a novel regulatory system responsible for mediating a cellular response to a high-cell-density environment.

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“…Escherichia coli strains JM109 (Yanisch-Perron et al, 1985), NM522 (Gough & Murray, 1983) (Miller, 1972) at 37 mC in a shaking incubator. Streptococcus mutans LT11 (Tao et al, 1993) Collection and grown at 37 mC in an anaerobic chamber in CDC broth [1 %, w\v, trypticase peptone and 1 %, w\v, trypticase soy broth (Difco), 1 %, w\v, yeast extract (Oxoid), 5 mg NaCl ml − ", 400 µg -cysteine ml − " (Sigma)] containing 5 µg haemin ml − " (Sigma), 2 µg menadione ml − " (Sigma) and 2% (v\v) horse serum (Commonwealth Serum Laboratories). Porphyromonas endodontalis ATCC 35406, obtained from the American Type Culture Collection, was also grown in an anaerobic chamber according to the method of Zerr et al (1998) Source of carious dentine.…”

Section: Methodsmentioning

confidence: 99%

Determination of bacterial load by real-time PCR using a broad-range (universal) probe and primers set

et al. 2002

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The design and evaluation of a set of universal primers and probe for the amplification of 16S rDNA from the Domain Bacteria to estimate total bacterial load by real-time PCR is reported. Broad specificity of the universal detection system was confirmed by testing DNA isolated from 34 bacterial species encompassing most of the groups of bacteria outlined in Bergey's Manual of Determinative Bacteriology. However, the nature of the chromosomal DNA used as a standard was critical. A DNA standard representing those bacteria most likely to predominate in a given habitat was important for a more accurate determination of total bacterial load due to variations in 16S rDNA copy number and the effect of generation time of the bacteria on this number, since rapid growth could result in multiple replication forks and hence, in effect, more than one copy of portions of the chromosome. The validity of applying these caveats to estimating bacterial load was confirmed by enumerating the number of bacteria in an artificial sample mixed in vitro and in clinical carious dentine samples. Taking these parameters into account, the number of anaerobic bacteria estimated by the universal probe and primers set in carious dentine was 40-fold greater than the total bacterial load detected by culture methods, demonstrating the utility of real-time PCR in the analysis of this environment.

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Transformation Efficiency of EMS-induced Mutants of Streptococcus mutans of Altered Cell Shape

Cited by 57 publications

References 29 publications

Dispensable genes and foreign DNA in Streptococcus mutans

Dispensable genes and foreign DNA in Streptococcus mutans

Genetic characterization of the hdrRM operon: a novel high-cell-density-responsive regulator in Streptococcus mutans

Determination of bacterial load by real-time PCR using a broad-range (universal) probe and primers set

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