Stability of plasmid PBR322 in Escherichia coli immobilized on cotton cloth during use as resident inoculum

1987 ◽  
Vol 9 (12) ◽  
pp. 825-830 ◽  
Author(s):  
Sushama Joshi ◽  
Hiroshi Yamazaki
2003 ◽  
Vol 185 (17) ◽  
pp. 5324-5327 ◽  
Author(s):  
Annie Conter

ABSTRACT The relationship between the survival of Escherichia coli during long-term starvation in rich medium and the supercoiling of a reporter plasmid (pBR322) has been studied. In aerated continuously shaken cultures, E. coli lost the ability to form colonies earlier in rich NaCl-free Luria-Bertani medium than in NaCl-containing medium, and the negative supercoiling of plasmid pBR322 declined more rapidly in the absence of NaCl. Addition of NaCl at the 24th hour restored both viability and negative supercoiling in proportion to the concentration of added NaCl. Addition of ofloxacin, a quinolone inhibitor of gyrase, abolished rescue by added NaCl in proportion to the ofloxacin added. This observation raises the possibility that cells had the ability to recover plasmid supercoiling even if nutrients were not available and could survive during long-term starvation in a manner linked, at least in part, to the topological state of DNA and gyrase activity.


1989 ◽  
Vol 54 (3) ◽  
pp. 167-171 ◽  
Author(s):  
Sabine Riethdorf ◽  
Andreas Schroeter ◽  
Michael Hecker

SummaryPlasmid pBR322 is amplified following amino-acid limitation inEscherichia coli relAhosts. InrelA+hosts there was no significant amplification or a much smaller one. Plasmid amplification is due to therelAmutation; when therelA+allele is transferred into therelAmutant CP79 this strain no longer amplifies plasmid DNA during amino acid starvation. It is concluded that ppGpp is a negative effector of plasmid replication. Amplification is temperature dependent, being maximal at 32 °C and negligible at 37 °C.


Genetics ◽  
1992 ◽  
Vol 130 (2) ◽  
pp. 241-249
Author(s):  
R I Modi ◽  
L H Castilla ◽  
S Puskas-Rozsa ◽  
R B Helling ◽  
J Adams

Abstract Two populations of Escherichia coli, each initiated with a single clone containing a derivative of the plasmid pBR322, were maintained for long periods in glucose-limited continuous culture. In both populations, after an extensive number of generations had elapsed, clones were isolated in which the transposon Tn3 from the plasmid had integrated into the bacterial chromosome. In both cases examined, the transpositions were shown to increase relative fitness approximately 6-7%, in the environment in which the populations were maintained. The loci of integration were mapped to approximately 13.2 min (population 1) and approximately 32.8 min (population 2).


1982 ◽  
Vol 152 (2) ◽  
pp. 954-958
Author(s):  
J K Keesey ◽  
J A Demoss

Studies with a hybrid plasmid containing 4.0 kilobase pairs of Neurospora crassa DNA cloned into plasmid pBR322 indicated that the plasmid restored to prototrophy a trpC mutant of Escherichia coli which lacked phosphoribosyl anthranilate isomerase but not a trpC mutant which lacked indole glycerol phosphate synthetase, that the relevant transcription was initiated at a promoter within the N. crassa DNA, and that the phosphoribosyl anthranilate isomerase could be specified by a subcloned segment of the original DNA.


1982 ◽  
Vol 152 (1) ◽  
pp. 524-526
Author(s):  
K Hardy ◽  
C Haefeli

Plasmid pBD9, which comprises two plasmids from Staphylococcus aureus, pE194 and pUB110, was joined to plasmid pBR322 by in vitro recombination to form plasmid pKH80. The ermC gene of plasmid pE194 confers inducible resistance to macrolide, lincosamide, and streptogramin type B antibiotics. When pKH80 was transferred to Escherichia coli K-12, the bacteria became resistant to several of these antibodies.


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