scholarly journals Exploitation of a β-lactamase reporter gene fusion in the carbapenem antibiotic production operon to study adaptive evolution in Erwinia carotovora

Microbiology ◽  
2006 ◽  
Vol 152 (4) ◽  
pp. 1089-1097 ◽  
Author(s):  
Steven D. Bowden ◽  
George P. C. Salmond
Keyword(s):  
Carboxylic Acid ◽  
Adaptive Evolution ◽  
Gene Fusion ◽  
Antibiotic Production ◽  
Erwinia Carotovora ◽  
Lactam Antibiotic ◽  
Resistant Mutants ◽  
Carbapenem Antibiotic ◽  
Reporter Gene Fusion ◽  
Engineered Strain

Erwinia carotovora subsp. carotovora strain ATTn10 produces the β-lactam antibiotic 1-carbapen-2-em-3-carboxylic acid (carbapenem) by expressing the carABCDEFGH operon. Mutants exhibiting increased carbapenem gene transcription were positively selected using an engineered strain with a functional β-lactamase translational fusion in carH, the last gene of the operon. However, spontaneous ampicillin-resistant mutants were isolated even when transcription of carH : : blaM was blocked by a strongly polar mutation in carE. The mechanism of resistance was shown to be due to cryptic IS10 elements transposing upstream of carH : : blaM, thereby providing new promoters enabling carH : : blaM transcription. Southern blots showed that IS10 was present in multicopy in ATTn10. In addition, a Tn10 genetic remnant was discovered. The results offer insights into the genetic archaeology of strain ATTn10 and highlight the powerful impacts of cryptic IS elements in bacterial adaptive evolution.

scholarly journals Cryptic carbapenem antibiotic production genes are widespread in Erwinia carotovora: facile trans activation by the carR transcriptional regulator

Microbiology ◽  
1998 ◽  
Vol 144 (6) ◽  
pp. 1495-1508 ◽  
Author(s):  
M. T. G. Holden ◽  
S. J. McGowan ◽  
B. W. Bycroft ◽  
G. S. A. B. Stewart ◽  
P. Williams ◽  
...  
Keyword(s):  
Antibiotic Production ◽  
Transcriptional Regulator ◽  
Erwinia Carotovora ◽  
Carbapenem Antibiotic

scholarly journals Carbapenem antibiotic production in Erwinia carotovora is regulated by CarR, a homologue of the LuxR transcriptional activator

Microbiology ◽  
1995 ◽  
Vol 141 (5) ◽  
pp. 1268-1268
Author(s):  
S. McGowan ◽  
M. Sebaihia ◽  
S. Jones ◽  
B. Yu ◽  
N. Bainton ◽  
...  
Keyword(s):  
Antibiotic Production ◽  
Transcriptional Activator ◽  
Erwinia Carotovora ◽  
Carbapenem Antibiotic

scholarly journals Carbapenem antibiotic production in Erwinia carotovora is regulated by CarR, a homologue of the LuxR transcriptional activator

Microbiology ◽  
1995 ◽  
Vol 141 (3) ◽  
pp. 541-550 ◽  
Author(s):  
S. McGowan ◽  
M. Sebaihia ◽  
S. Jones ◽  
B. Yu ◽  
N. Bainton ◽  
...  
Keyword(s):  
Antibiotic Production ◽  
Transcriptional Activator ◽  
Erwinia Carotovora ◽  
Carbapenem Antibiotic

Bacteriophage T4 resistant mutants of the plant pathogen Erwinia carotovora

1988 ◽  
Vol 4 (5) ◽  
pp. 359-367 ◽  
Author(s):  
Minna Pirhonen ◽  
Pekka Heino ◽  
Ilkka Helander ◽  
Pirkko Harju ◽  
E.Tapio Palva
Keyword(s):  
Plant Pathogen ◽  
Bacteriophage T4 ◽  
Erwinia Carotovora ◽  
Resistant Mutants

scholarly journals Effects of Subinhibitory Concentrations of Antibiotics on SOS and DNA Repair Gene Expression in Staphylococcus aureus

2008 ◽  
Vol 52 (9) ◽  
pp. 3394-3397 ◽  
Author(s):  
Lili Rosana Mesak ◽  
Vivian Miao ◽  
Julian Davies
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Dna Repair ◽  
Gene Fusion ◽  
Sos Response ◽  
Repair Gene ◽  
Mmr Genes ◽  
Dna Repair Gene ◽  
Transcriptional Modulation ◽  
Resistant Mutants

ABSTRACT Reporter clones of Staphylococcus aureus with different SOS response- and DNA repair-associated promoter-lux gene fusion constructs were constructed to study the effects of sub-MICs of antibiotics on the transcription of the SOS and methyl mismatch repair (MMR) genes. Fluoroquinolones (FQs) upmodulated both the SOS and the MMR genes. The patterns of antibiotic-induced transcriptional modulation were altered in FQ-resistant mutants.

Enhanced ?-lactam antibiotic production by coimmobilization of fungus and alga

1988 ◽  
Vol 10 (12) ◽  
pp. 867-872 ◽  
Author(s):  
Yong Ho Khang ◽  
Hariharan Shankar ◽  
Fred Senatora
Keyword(s):  
Antibiotic Production ◽  
Lactam Antibiotic

Virulence of Pseudomonas aeruginosa strains with mechanisms of microbial persistence for β-lactam and aminoglycoside antibiotics in a mouse infection model

1985 ◽  
Vol 31 (4) ◽  
pp. 377-380 ◽  
Author(s):  
L. E. Bryan ◽  
A. J. Godfrey ◽  
T. Schollardt
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Therapeutic Failure ◽  
Infection Model ◽  
Iron Dextran ◽  
Mechanisms Of Resistance ◽  
Penicillin Binding Proteins ◽  
Mouse Infection Model ◽  
Lactam Antibiotic ◽  
Resistant Mutants ◽  
Mechanisms Of Persistence

A series of mutations and transductants producing low-level aminoglycoside and β-lactam antibiotic resistance of Pseudomonas aeruginosa have been constructed in an isogenic background. The phenotypes of these mutations are identical to or closely resemble those of clinical isolates of P. aeruginosa associated with therapeutic failure or microbial persistence in the presence of members of one or both groups of drugs. Virulence of the mutants was examined in an infection model using iron–dextran treated mice and bacteria grown in low-iron medium. All β-lactam resistant mutants affecting affinity of penicillin-binding proteins for β-lactams, constitutive β-lactamase, or permeability of β-lactams retained parental levels of virulence. Aminoglycoside-resistant mutants with defective energy generation or transductants with modified lipopolysaccharide showed reduced virulence. Strains with the preceding forms of resistance are likely to account for therapeutic failure or microbial persistence with antibiotic treatment. We propose that mechanisms of low or unstable forms of resistance should be designated mechanisms of persistence to differentiate them from more classical mechanisms of resistance.

scholarly journals Mutations in rpsL that confer streptomycin resistance show pleiotropic effects on virulence and the production of a carbapenem antibiotic in Erwinia carotovora

Microbiology ◽  
2010 ◽  
Vol 156 (4) ◽  
pp. 1030-1039 ◽  
Author(s):  
Anne M. L. Barnard ◽  
Natalie J. L. Simpson ◽  
Kathryn S. Lilley ◽  
George P. C. Salmond
Keyword(s):  
Quorum Sensing ◽  
Erwinia Carotovora ◽  
Homoserine Lactone ◽  
Base Change ◽  
Signalling Molecule ◽  
Intracellular Proteins ◽  
Single Base Change ◽  
Ribosomal Protein S12 ◽  
Derivatives Of ◽  
Carbapenem Antibiotic

Spontaneous streptomycin-resistant derivatives of Erwinia carotovora subsp. carotovora strain ATTn10 were isolated. Sequencing of the rpsL locus (encoding the ribosomal protein S12) showed that each mutant was missense, with a single base change, resulting in the substitution of the wild-type lysine by arginine, threonine or asparagine at codon 43. Phenotypic analyses showed that the rpsL mutants could be segregated into two groups: K43R mutants showed reduced production of the β-lactam secondary metabolite 1-carbapen-2-em-3 carboxylic acid (Car), but little effect on exoenzyme production or virulence in potato tuber tests. By contrast, the K43N and K43T mutations were pleiotropic, resulting in reduced exoenzyme production and virulence, as well as diminished Car production. The effect on Car production was due to reduced transcription of the quorum-sensing-dependent car biosynthetic genes. The effects of K43N and K43T mutations on Car production were partially alleviated by provision of an excess of the quorum-sensing signalling molecule N-(3-oxohexanoyl)-l-homoserine lactone. Finally, a proteomic analysis of the K43T mutant indicated that the abundance of a subset of intracellular proteins was affected by this rpsL mutation.

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