Glycine betaine reverses the effects of osmotic stress on DNA replication and cellular division in Escherichia coli.
The accumulation of glycine betaine to a high internal concentration by Escherichia coli cells in high osmolarity medium restores, within 1 h, a subnormal growth rate. The experimental results support the view that cell adaptation to high osmolarity involves a decrease in the initiation frequency of DNA replication via a stringent response; in contrast, glycine betaine transport and accumulation could suppress the stringent response within 1-2 min and restore a higher initiation frequency. High osmolarity also triggers the cells to lengthen, perhaps via an inhibition of cellular division; glycine betaine also reverses this process. It is inferred that turgor could control DNA replication and cell division in two separate ways. Glycine betaine action is not mediated by K+ ions as the internal level of K+ ions is not modified significantly following glycine betaine accumulation.
Meury
J
J
Institut Jacques Monod, Université Paris VII, France.
D001426:Bacterial Proteins / Q000096:biosynthesis; D001622:Betaine / Q000378:metabolism*; D002455:Cell Division; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D009154:Mutation; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D011188:Potassium / Q000378:metabolism
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D001622:Betaine; D011188:Potassium