Global transcriptional response of Escherichia coli O157:H7 to growth transitions in glucose minimal medium

Sodium benzoate is a widely used food antimicrobial in drinks and fruit juices. A microarray study was conducted to determine the transcriptional response of Escherichia coli O157:H7 to 0.5% (wt/vol) sodium benzoate. E. coli O157:H7 grown in 150 ml of Luria-Bertani broth was exposed to 0% (control) and 0.5% sodium benzoate. Each treatment was duplicated and sampled at 0 (immediately after exposure), 5, 15, 30, and 60 min. Total RNA was extracted and analyzed with E. coli 2.0 Gene Chips. Significant ontology categories affected by sodium benzoate exposure were determined with JProGO software. The phosphate-specific transport (Pst) system transports inorganic phosphate into bacterial cells, under phosphate-limited conditions. The Pst system was found to be highly upregulated. Increased expression of the Pst system was observed after the short 5 min of exposure to sodium benzoate; pstS, pstA, pstB, and pstC genes were upregulated more than twofold (linear scale) at 5, 15, 30, and 60 min. Increased expression of several other efflux systems, such as AcrAB-TolC, was also observed. The Pst system may act as an efflux pump under these stress-adapted conditions, as well as increase transport of phosphorus to aid in DNA, RNA, ATP, and phospholipid production. Understanding adaptations of Escherichia coli O157:H7 under antimicrobial exposure is essential to better understand and implement methods to inhibit or control its survival in foods.

Download Full-text

Mechanisms Causing Rapid and Parallel Losses of Ribose Catabolism in Evolving Populations of Escherichia coli B

Journal of Bacteriology ◽

10.1128/jb.183.9.2834-2841.2001 ◽

2001 ◽

Vol 183 (9) ◽

pp. 2834-2841 ◽

Cited By ~ 186

Author(s):

Vaughn S. Cooper ◽

Dominique Schneider ◽

Michel Blot ◽

Richard E. Lenski

Keyword(s):

Escherichia Coli ◽

Minimal Medium ◽

Molecular Genetic ◽

Selective Advantage ◽

Gene Replacement ◽

High Rate ◽

Glucose Minimal Medium ◽

Fluctuation Test ◽

The One ◽

Escherichia Coli B

ABSTRACT Twelve populations of Escherichia coli B all lostd-ribose catabolic function during 2,000 generations of evolution in glucose minimal medium. We sought to identify the population genetic processes and molecular genetic events that caused these rapid and parallel losses. Seven independent Rbs−mutants were isolated, and their competitive fitnesses were measured relative to that of their Rbs+ progenitor. These Rbs− mutants were all about 1 to 2% more fit than the progenitor. A fluctuation test revealed an unusually high rate, about 5 × 10−5 per cell generation, of mutation from Rbs+ to Rbs−, which contributed to rapid fixation. At the molecular level, the loss of ribose catabolic function involved the deletion of part or all of the ribose operon (rbs genes). The physical extent of the deletion varied between mutants, but each deletion was associated with an IS150 element located immediately upstream of therbs operon. The deletions apparently involved transposition into various locations within the rbs operon; recombination between the new IS150 copy and the one upstream of therbs operon then led to the deletion of the intervening sequence. To confirm that the beneficial fitness effect was caused by deletion of the rbs operon (and not some undetected mutation elsewhere), we used P1 transduction to restore the functionalrbs operon to two Rbs− mutants, and we constructed another Rbs− strain by gene replacement with a deletion not involving IS150. All three of these new constructs confirmed that Rbs− mutants have a competitive advantage relative to their Rbs+ counterparts in glucose minimal medium. The rapid and parallel evolutionary losses of ribose catabolic function thus involved both (i) an unusually high mutation rate, such that Rbs− mutants appeared repeatedly in all populations, and (ii) a selective advantage in glucose minimal medium that drove these mutants to fixation.

Download Full-text

The Small RNA GcvB Regulates sstT mRNA Expression in Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.00915-08 ◽

2008 ◽

Vol 191 (1) ◽

pp. 238-248 ◽

Cited By ~ 34

Author(s):

Sarah C. Pulvermacher ◽

Lorraine T. Stauffer ◽

George V. Stauffer

Keyword(s):

Escherichia Coli ◽

Minimal Medium ◽

Small Region ◽

Luria Bertani ◽

Negative Regulation ◽

Transport Systems ◽

Mrna Levels ◽

Glucose Minimal Medium ◽

Reverse Transcription Pcr ◽

Luria Bertani Broth

ABSTRACT In Escherichia coli, the gcvB gene encodes a nontranslated RNA (referred to as GcvB) that regulates OppA and DppA, two periplasmic binding proteins for the oligopeptide and dipeptide transport systems. An additional regulatory target of GcvB, sstT, was found by microarray analysis of RNA isolated from a wild-type strain and a gcvB deletion strain grown to mid-log phase in Luria-Bertani broth. The SstT protein functions to transport l-serine and l-threonine by sodium transport into the cell. Reverse transcription-PCR and translational fusions confirmed that GcvB negatively regulates sstT mRNA levels in cells grown in Luria-Bertani broth. A series of transcriptional fusions identified a region of sstT mRNA upstream of the ribosome binding site needed for negative regulation by GcvB. Analysis of the GcvB RNA identified a sequence complementary to this region of the sstT mRNA. The region of GcvB complementary to sstT mRNA is the same region of GcvB identified to regulate the dppA and oppA mRNAs. Mutations predicted to disrupt base pairing between sstT mRNA and GcvB were made in gcvB, which resulted in the identification of a small region of GcvB necessary for negative regulation of sstT-lacZ. Additionally, the RNA chaperone protein Hfq was found to be necessary for GcvB to negatively regulate sstT-lacZ in Luria-Bertani broth and glucose minimal medium supplemented with glycine. The sstT mRNA is the first target found to be regulated by GcvB in glucose minimal medium supplemented with glycine.

Download Full-text

Construction of an Escherichia coli strain which excretes abnormally large amounts of adenosine 3′,5′-cyclic monophosphate

Canadian Journal of Microbiology ◽

10.1139/m78-228 ◽

1978 ◽

Vol 24 (11) ◽

pp. 1423-1425 ◽

Cited By ~ 10

Author(s):

Ann D. E. Fraser ◽

Hiroshi Yamazaki

Keyword(s):

Escherichia Coli ◽

Minimal Medium ◽

Coli Strain ◽

Coli Cell ◽

Wild Type ◽

Camp Phosphodiesterase ◽

E Coli ◽

Cyclic Monophosphate ◽

Glucose Minimal Medium ◽

P1 Transduction

It has previously been shown that an Escherichia coli CRP− strain 5333 accumulates abnormally large amounts of adenosine 3′,5′-cyclic monophosphate (cAMP). Using P1 transduction, the CRP− character was transferred to E. coli Crookes strain which is deficient for cAMP phosphodiesterase (CPD−). The resulting strain HY22 (CRP−, CPD−) accumulates greater amounts of cAMP both intracellularly and extracellularly than does 5333. In glucose minimal medium, an HY22 cell accumulates 100 times more cAMP intracellularly and excretes cAMP 150 times faster than does a wild-type E. coli cell.

Download Full-text

YjjG, a dUMP Phosphatase, Is Critical for Thymine Utilization by Escherichia coli K-12

Journal of Bacteriology ◽

10.1128/jb.01645-06 ◽

2006 ◽

Vol 189 (5) ◽

pp. 2186-2189 ◽

Cited By ~ 12

Author(s):

Bernard Weiss

Keyword(s):

Escherichia Coli ◽

Thymidylate Synthase ◽

Minimal Medium ◽

Glucose Minimal Medium ◽

K 12

ABSTRACT Exogenous thymine must be converted to thymidine to enable a thyA (thymidylate synthase) mutant to grow. The deoxyribose in the thymidine comes from dUMP, which must first be dephosphorylated. The nucleotidase YjjG is critical for this step. A yjjG thyA mutant cannot use thymine for growth on a glucose minimal medium.

Download Full-text

Bedeutung von Escherichia coli O157 beim Schlachtschaf in der Schweiz

Schweizer Archiv für Tierheilkunde ◽

10.1024/0036-7281.148.6.289 ◽

2006 ◽

Vol 148 (6) ◽

pp. 289-295 ◽

Cited By ~ 8

Author(s):

C. Zweifel ◽

M. Kaufmann ◽

J. Blanco ◽

R. Stephan

Keyword(s):

Escherichia Coli ◽

Escherichia Coli O157

Download Full-text

Molecular profiling and antimicrobial susceptibility of Escherichia coli O157:H7 isolated in Bulgaria

BULGARIAN JOURNAL OF VETERINARY MEDICINE ◽

10.15547/bjvm.2263 ◽

2020 ◽

Vol 23 (3) ◽

pp. 310-318

Author(s):

K. Koev ◽

T. Stoyanchev ◽

G. Zhelev ◽

P. Marutsov ◽

K. Gospodinova ◽

...

Keyword(s):

Escherichia Coli ◽

Escherichia Coli O157 ◽

Acid Sensitivity ◽

Lower Extent ◽

Phenotype Analysis ◽

Anal Swab ◽

Amoxicillin Clavulanic Acid ◽

Primary Identification ◽

Stx1 Gene ◽

Cattle Farms

The purpose of this study was to detect the presence of shiga-toxin producing Escherichia coli (STEC) in faeces of healthy dairy cattle and to determine the sensitivity of isolates to several antimicrobial drugs. A total of 1,104 anal swab samples originating from 28 cattle farms were examined. After the primary identification, 30 strains were found to belong to serogroup О157. By means of conventional multiplex PCR, isolates were screened for presence of resistance genes stx1, stx2 and eaeА. Twenty-nine strains possesses amplicons with a size corresponding to genes stx2 and eaeA, one had amplicons also for the stx1 gene and one lacked amplicons of all three genes. Twenty-eight strains demonstrated amplicons equivalent to gene H7. The results from phenotype analysis of resistance showed preserved sensitivity to ceftriaxone, ceftazidime, cefotaxime, cephalothin, streptomycin, gentamicin, tetracycline, enrofloxacin and combinations sulfamethoxazole/trimethoprim and amoxicillin/clavulanic acid. Sensitivity to ampicillin was relatively preserved, although at a lower extent.

Download Full-text