Selective enrichment for genetic markers in DNA released by competent cultures of Bacillus subtilis
✍ Scribed by Crabb, W. Douglas ;Streips, Uldis N. ;Doyle, R. J.
- Publisher
- Springer
- Year
- 1977
- Tongue
- English
- Weight
- 424 KB
- Volume
- 155
- Category
- Article
- ISSN
- 0026-8925
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✦ Synopsis
Deoxyribonucleic acid is released into the growth medium by Bacillus subtilis at the time of competence. This DNA is enriched for the genetic markers which have previously been demonstrated to be elevated in membrane-DNA preparations and more recently in cell wall-DNA complexes. Furthermore, the purA16/leu-8 relative marker enrichment varies with time, reaching its highest point at the time of maximal competence. Enrichment remains elevated for at least 60 min further in the competence regimen. The results suggest that certain genetic markers of the B. subtilis chromosome are preferentially more available to the external medium as the development of competence proceeds.
Streips and Young [9] showed the differential release ofpurA16 when compared to leu-8 in two strains of B. subtilis. These results suggested that certain markers on the B. subtilis genome may be more available for release into the medium than others. In this communication, we report the preferential release at the time of competence of certain genetic markers particularly those associated with both the replication origin and terminus. These same enriched markers have subsequently been shown to be enhanced in cell wall-DNA complexes isolated from B. subtiIis [4,8]. This association of the chromosome with the cell wall may facilitate the overall release mechanism and may explain the preferential appearance in the medium of specific regions of the chromosome.