title: Stability of plasmid pHV1431 in free and immobilized cell cultures. Effect of temperature.
abstract: The segregational and structural stability of pHV1431 has been examined in Bacillus subtilis grown at 30 and 37 degrees C in continuous cultures without selection pressure. Immediately after appearance of plasmid-free cells in the reactor, a competition was observed between bacteria that favored plasmid-free cells because of the faster growth. A stronger instability was found at 30 degrees C compared to that at 37 degrees C. At 30 degrees C after 50 hours of culture, 2% of the cells carried the plasmid, whereas at 37 degrees C this percentage was reached after 130 hours. In both cases, no structural instability was observed. To improve the stability, the recombinant Bacillus subtilis (pHV1431) was immobilized in kappa-carrageenan gel beads. In comparison to free cell systems, a higher cell concentration was obtained. Moreover, the plasmid was maintained stable for longer periods; after 150 hours of culture 40% of cells in the reactor still carried the plasmid at both temperatures.
authors.affiliation: Laboratoire de Technologie Enzymatique, URA CNRS 1442, Universitë de Technologie de Compiègne, France.
authors.forename: M
authors.initials: M
authors.lastname: Craynest
authors.forename: J N
authors.initials: JN
authors.lastname: Barbotin
authors.forename: N
authors.initials: N
authors.lastname: Truffaut
authors.forename: D
authors.initials: D
authors.lastname: Thomas
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics* / Q000648:ultrastructure; D001431:Bacteriological Techniques; D018914:Cells, Immobilized; D004269:DNA, Bacterial / Q000032:analysis; D004355:Drug Stability; D013293:Enterococcus faecalis / Q000235:genetics*; D008855:Microscopy, Electron, Scanning; D010957:Plasmids / Q000648:ultrastructure; D013211:Staphylococcus aureus / Q000235:genetics*; D013696:Temperature; D013997:Time Factors
chemical_list: D004269:DNA, Bacterial