Selective enrichment for genetic markers in DNA released by competent cultures of Bacillus subtilis

Crabb, W D; Streips, Uldis N.; Doyle, Ronald J.

doi:10.1007/bf00393157

Cited by 22 publications

(15 citation statements)

References 12 publications

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“…In fact, essentially all bacteria release DNA during some point of their growth in standard culture media (Lorenz and Wackernagel, 1994). There is also evidence demonstrating that both plasmid and chromosomal DNA could be released from B. subtilis cells coincidental with the development of competence (Crabb et al, 1977;Lorenz et al, 1991). These studies suggest that there is association of an unknown substance involved in externalization of DNA, possibly involving active transport, or variations in the cell wall leading to passive release.…”

Section: The Fate Of Dna In Salivamentioning

confidence: 90%

Genetic Competence and Transformation in Oral Streptococci

Cvitkovitch

2001

Critical Reviews in Oral Biology & Medicine

111

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The oral streptococci are normally non-pathogenic residents of the human microflora. There is substantial evidence that these bacteria can, however, act as "genetic reservoirs" and transfer genetic information to transient bacteria as they make their way through the mouth, the principal entry point for a wide variety of bacteria. Examples that are of particular concern include the transfer of antibiotic resistance from oral streptococci to Streptococcus pneumoniae. The mechanisms that are used by oral streptococci to exchange genetic information are not well-understood, although several species are known to enter a physiological state of genetic competence. This state permits them to become capable of natural genetic transformation, facilitating the acquisition of foreign DNA from the external environment. The oral streptococci share many similarities with two closely related Gram-positive bacteria, S. pneumoniae and Bacillus subtilis. In these bacteria, the mechanisms of quorum-sensing, the development of competence, and DNA uptake and integration are well-characterized. Using this knowledge and the data available in genome databases allowed us to identify putative genes involved in these processes in the oral organism Streptococcus mutans. Models of competence development and genetic transformation in the oral streptococci and strategies to confirm these models are discussed. Future studies of competence in oral biofilms, the natural environment of oral streptococci, will be discussed.

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Section: The Fate Of Dna In Salivamentioning

confidence: 90%

Genetic Competence and Transformation in Oral Streptococci

Cvitkovitch

2001

Critical Reviews in Oral Biology & Medicine

111

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“…eDNA was first reported to be released by different laboratory strains, such as the 168 strain, during exponential and early stationary phase (Sinha and Iyer, 1971; Lorenz et al, 1991), and this eDNA was proposed to have a role in HGT (Crabb et al, 1977; Lorenz et al, 1991). However, B. subtilis laboratory strains have lost some social behaviors as a result of genetic modifications and pressure selection that facilitated their manipulation in the laboratory.…”

Section: Edna Production In Cultured Microorganismsmentioning

confidence: 99%

Mechanisms and Regulation of Extracellular DNA Release and Its Biological Roles in Microbial Communities

2017

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The capacity to release genetic material into the extracellular medium has been reported in cultures of numerous species of bacteria, archaea, and fungi, and also in the context of multicellular microbial communities such as biofilms. Moreover, extracellular DNA (eDNA) of microbial origin is widespread in natural aquatic and terrestrial environments. Different specific mechanisms are involved in eDNA release, such as autolysis and active secretion, as well as through its association with membrane vesicles. It is noteworthy that in microorganisms, in which DNA release has been studied in detail, the production of eDNA is coordinated by the population when it reaches a certain cell density, and is induced in a subpopulation in response to the accumulation of quorum sensing signals. Interestingly, in several bacteria there is also a relationship between eDNA release and the development of natural competence (the ability to take up DNA from the environment), which is also controlled by quorum sensing. Then, what is the biological function of eDNA? A common biological role has not been proposed, since different functions have been reported depending on the microorganism. However, it seems to be important in biofilm formation, can be used as a nutrient source, and could be involved in DNA damage repair and gene transfer. This review covers several aspects of eDNA research: (i) its occurrence and distribution in natural environments, (ii) the mechanisms and regulation of its release in cultured microorganisms, and (iii) its biological roles. In addition, we propose that eDNA release could be considered a social behavior, based on its quorum sensing-dependent regulation and on the described functions of eDNA in the context of microbial communities.

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“…These results, taken together with the fact that with the development of competence nonlysogenic cells also lyse and release their chromosomal DNA into the medium, 36,37) prompted us to examine the possibility that genetic transformation would occur spontaneously in a mixed cell culture without the addition of exogenous DNA. Two strains carrying different genetic markers were co-cultivated in CSM and the number of transformants of each strain at hourly intervals was scored by spreading the culture on selection agar plates (Fig.…”

Section: Spontaneous Genetic Transformation In a Mixed Cell Culture Imentioning

confidence: 99%