Sporenbildung in wachsenden Bacillus subtilis-Kulturen und ihre Korrelation zur Kompetenz für genetische Transformation

✍ Scribed by Dr. S. Kretschmer

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 790 KB
• Volume: 13
• Category: Article
• ISSN: 0233-111X
• DOI: 10.1002/jobm.19730130305

✦ Synopsis

Using shift‐experiments it was shown that there are two kinds of spores in Bacillus subtilis 168 differing in their genesis. Spores, which develop to a small extent in nonlimitated cultures are called NL‐spores, while the other ones, whose formation is initiated by growth‐limitation, are called L‐spores. The development of NL‐spores took 2.5 hrs. more than that of L‐spores. This prolongation was due to a presporulation stage, during which cells do not divide, and apparently no sporulation‐specific metabolism is expressed, Addition of glutamic acid to the glucose‐salt‐medium did not influence the frequency of cells passing from growth to the presporulation stage. But its presence prevented these resting cells from entering the sporulation stage, which they did in the glutamic acid‐free medium after having passed through the 2.5 hrs. lasting presporulation stage.

Cells developing competence for genetic transformation resemble to some extent sporulating cells. But as they do not appear under growth‐limiting conditions, it seems likely that competence may be connected only with the NL‐sporulation. Comparison of the kinetics as well as the frequency of transformation and NL‐sporogenesis do favour this hypothesis. Competence than would correspond to the last 50 min of the presporulation stage of the NL‐sporogenesis. But additional factors are involved in the expression of competence in cells being at that stage.