[Spontaneous transformation characteristics of Bacillus subtilis bacteria. I. The relatively low transforming activity of spontaneously released DNA for markers located close to the origin and termination points of chromosome replication].
Relative efficiencies of spontaneous Bacillus subtilis transformation for markers placed in different areas of the cell chromosome were studied. As donor of genetic material, an untransformable strain BD224 trpC2 thr5 rec4 was used during its early log-phase. It was found that for markers placed near points of origin and termination of the chromosome replication the relative transformation efficiencies are significantly lower than those in the case of transformation with DNA extracted from the same donor cells. If a contact of spontaneously released DNA with the recipient cells was delayed for about 60 minutes ("separate" experiment) this difference proved to be less pronounced for ade16 placed near the origin, but remained practically unchanged for metB placed near the termination point. The results obtained can be explained by permanent attachment of chromosome regions, carrying "origin" and "termination" points, to a cytoplasmic membrane. During spontaneously release of cellular genetic material, "origin" and "terminal" DNA fragments carrying ade16 and metB respectively, can retain the contact with components of cell membrane. Hence, their penetration in the recipient cell and (or) participation in recombination can be violated. The first of two fragments becomes free from structurating substances more easy.
D001412:Bacillus subtilis / Q000235:genetics*; D002876:Chromosomes, Bacterial / Q000648:ultrastructure*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics*; D005819:Genetic Markers; D011995:Recombination, Genetic / Q000187:drug effects; D014169:Transformation, Bacterial
D004269:DNA, Bacterial; D005819:Genetic Markers
Issledovanie osobennosteĭ spontannoĭ transformatsii u bakteriĭ Bacillus subtilis. Soobshchenie I. Otnositel'no nizkaia transformiruiushchaia aktivnost' spontanno vydelennoĭ DNK po markeram, lokalizovannym vblizi tochek nachala i kontsa replikatsii khromosomy.