title: Mutant of Escherichia coli with thermosensitive protein in the process of cellular division.
abstract: A new thermosensitive mutant of Escherichia coli deficient in cell division was isolated by means of membrane filtration after nitrosoguanidine mutagenesis. The mutant cells grow normally at 30 C but stop dividing immediately after shift to 42 C, resulting in multinucleated filaments lacking septa. The number of colony-forming units does not decrease for at least 6 hr at 42 C. The maximum length of the filaments is 10 to 16 times that of normal cells. Addition of a high concentration of NaCl fails to stimulate cell division at 42 C. The filaments formed at 42 C divide abruptly 30 min after shift to 30 C, and synchronous increase of cell number is shown for 3 hr. The macromolecular synthesis of protein and nucleic acids at 42 C is normal on the whole. The cell division shown after the shift from 42 to 30 C is observed in the absence of thymine, but not in the presence of chloramphenicol or in a medium deficient in amino acids. However, the filament can divide to some extent in the presence of chloramphenicol if some protein synthesis is allowed to proceed at 30 C before the addition of the antibiotic. The elongated cells divide at 42 C provided that they are exposed to 30 C before being shifted to high temperature.
mesh_terms: D000225:Adenine / Q000378:metabolism; D001426:Bacterial Proteins / Q000096:biosynthesis; D002247:Carbon Isotopes; D002455:Cell Division; D002701:Chloramphenicol / Q000494:pharmacology; D003470:Culture Media; D004269:DNA, Bacterial / Q000096:biosynthesis; D004926:Escherichia coli / Q000166:cytology* / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D005374:Filtration; D007930:Leucine / Q000378:metabolism; D008854:Microscopy, Electron; D008858:Microscopy, Phase-Contrast; D008954:Models, Biological; D009153:Mutagens; D009154:Mutation; D009604:Nitrosoguanidines; D012329:RNA, Bacterial / Q000096:biosynthesis; D013194:Staining and Labeling; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D002247:Carbon Isotopes; D003470:Culture Media; D004269:DNA, Bacterial; D009153:Mutagens; D009604:Nitrosoguanidines; D012329:RNA, Bacterial; D002701:Chloramphenicol; D007930:Leucine; D000225:Adenine