Transport of Donor Deoxyribonucleic Acid into the Cell Interior of Thymine-starved
            <i>Bacillus subtilis</i>
            with Chromosomes Arrested at the Terminus

Self Cite

Recently developed differential plating media permit the distinction of four cell types in incompletely protoplasted populations: intact, osmotically insensitive bacilli; osmotically sensitive rods; spheres with adherent wall residues, called quasi spheroplasts; and protoplasts. Such population mixtures were washed free of lysozyme, and then transforming deoxyribonucleic acid (DNA) was added. Transformation was nil in the protoplasts, very low in the residual osmotically insensitive bacilli, and markedly enhanced in both osmotically sensitive rods and quasi spheroplasts. Transformation in the latter two population fractions was reduced, respectively, by about 60% and about 80% by deoxyribonuclease treatment. DNA adhering to the quasi spheroplasts transforms these cells only if they are permitted to resume wall synthesis; when the same cells are plated on a medium where they shed 42

Section: Discussionsupporting

confidence: 93%

Transformation in Quasi Spheroplasts of Bacillus subtilis

Tichý

Landman

1969

Self Cite

“…In particular, it is clear that a label such as "exponentially growing" or "stationary phase" cannot be applied to our chromosome-arrested cultures. Similarly, it is clear from our experiments that cell division cannot play an essential role in competence development, or, for that matter, in marker intake (4). Development of competence in the absence of chromosome replication.…”

Section: Development Of Competence In Cultures Withsupporting

confidence: 55%

“…Proc., p. 52,1967). They are detailed in this and the accompanying report (4), which describes marker entry in chromosome-arrested cells (4). The present report presents the methods whereby we obtained competent cultures with chromosomes synchronously arrested at the terminus.…”

mentioning

confidence: 94%

Development of Competence in Thymine-starved Bacillus subtilis with Chromosomes Arrested at the Terminus

Archer

Landman

1969

Self Cite

Tryptophan-and thymine-requiring cells of Bacillus subtilis, emerging from an amino acid starvation treatment which causes arrest of the chromosomes at the terminus, were not transformable. During subsequent incubation in a thymineless medium supplemented with amino acids, the cultures developed competence while retaining chromosome arrest. The competent subpopulation apparently shares the synchronous chromosome arrest of the bulk population. This was shown by different methods. The principal method was marker frequency analysis of the deoxyribonucleic acid extracted from a population enriched for competent cells by a column-chromatographic method. It is concluded that development of the competent state can occur in nondividing cells, and that the presence of a replication fork actively engaged in synthesis of deoxyribonucleic acid is not required for the development of this state.

“…The present work may support the assumption that this is the mechanism in N. meningitidis. Recently, Erickson and Braun (4) found that transformation in B. subtilis could also be explained in this way, whereas Archer and Landman (1) concluded that this was not the case. Both of these research groups have also studied the consequences of chromosome alignment for the transformation of various markers.…”

Section: Discussionmentioning

confidence: 99%

Sequential Entry of Transforming Markers into Neisseria meningitidis After Chromosome Alignment

Jyssum

1969

The kinetics of appearance of transformants as a function of time of exposure to deoxyribonucleic acid (DNA) was examined in Neisseria meningitidis . Incubation with chloramphenicol for as long as 2 hr, which probably leads to chromosome alignment, resulted in augmentation of the lag period before the appearance of the first transformants. The lag periods thus found were dependent upon the marker tested. This permitted the construction of a time map according to the lag periods observed for individual markers. This map was in general agreement with the chromosome map of the recipient strain as determined by marker frequency analysis. Transformation of recipient cells with chromosomes aligned by growth to the stationary phase showed the same type of increased lag in the appearance of transformants before the logarithmic phase of growth had again been reached. These results support the assumption that the nature of the marker accepted by a recipient cell corresponds to the marker present at the replication point of the chromosome. In the absence of DNA and protein synthesis, the uptake of one marker seems to be successively followed by other markers in a linear order determined by the chromosome of the recipient cell.