scholarly journals Novel kinetic and structural properties of the class-I D-fructose 1,6-bisphosphate aldolase from Escherichia coli (Crookes' strain)

1978 ◽  
Vol 169 (3) ◽  
pp. 643-652 ◽  
Author(s):  
S A Baldwin ◽  
R N Perham
Keyword(s):  
Escherichia Coli ◽  
Structural Properties ◽  
Strong Dependence ◽  
Class I ◽  
Kinetic Properties ◽  
E Coli ◽  
Cleavage Activity ◽  
Polycarboxylic Acids ◽  
Class 1 ◽  
Fructose 1,6 Bisphosphate

Investigation of aldolase 1, the class-I D-fructose 1,6-bisphosphate aldolase (EC4.1.2.13) from Escherichia coli (Crookes' strain), showed it to have unusual kinetic and structural properties. The enzyme appeared to be larger than was previously supposed and may be a decamer with a mol. wt. of approx. 340000. Its fructose 1,6-bisphosphate-cleavage activity was unaffected by these compounds. The enhancement exhibited a strong dependence on pH. These novel kinetic properties do not seem to be shared by any other fructose 1,6-bisphosphate aldolase, but recall the activation by polycarboxylic acids of the deoxyribose 3-phosphate aldolases from some other organisms. In view of its unusual properties, it is unlikely that aldolase 1 from E. coli is closely related to the class-1 aldolases that have been detected in several other prokaryotes, or to the typical class-1 enzymes from eukaryotes.

scholarly journals The dhnA gene of Escherichia coli encodes a Class I fructose bisphosphate aldolase

1998 ◽  
Vol 331 (2) ◽  
pp. 437-445 ◽  
Author(s):  
Graeme J. THOMSON ◽  
Geoffrey J. HOWLETT ◽  
Alison E. ASHCROFT ◽  
Alan BERRY
Keyword(s):  
Escherichia Coli ◽  
Lysine Residue ◽  
Site Directed Mutagenesis ◽  
Class I ◽  
Fructose Bisphosphate ◽  
Gene Encoding ◽  
E Coli ◽  
Native Molecular Mass ◽  
Fructose Bisphosphate Aldolase ◽  
Fructose 1,6 Bisphosphate

The gene encoding the Escherichia coli Class I fructose-1,6-bisphosphate aldolase (FBP aldolase) has been cloned and the protein overproduced in high amounts. This gene sequence has previously been identified as encoding an E. coli dehydrin in the GenBank™ database [gene dhnA; entry code U73760; Close and Choi (1996) Submission to GenBank™]. However, the purified protein overproduced from the dhnA gene shares all its properties with those known for the E. coli Class I FBP aldolase. The protein is an 8–10-mer with a native molecular mass of approx. 340 kDa, each subunit consisting of 349 amino acids. The Class I enzyme shows low sequence identity with other known FBP aldolases, both Class I and Class II (in the order of 20%), which may be reflected by some novel properties of this FBP aldolase. The active-site peptide has been isolated and the Schiff-base-forming lysine residue (Lys236) has been identified by a combination of site-directed mutagenesis, kinetics and electrospray-ionization MS. A second lysine residue (Lys238) has been implicated in substrate binding. The cloning of this gene and the high levels of overexpression obtained will facilitate future structure–function studies.

scholarly journals Mechanisms of Resistance in Multiple-Antibiotic-Resistant Escherichia coli Strains of Human, Animal, and Food Origins

2004 ◽  
Vol 48 (10) ◽  
pp. 3996-4001 ◽  
Author(s):  
Yolanda Sáenz ◽  
Laura Briñas ◽  
Elena Domínguez ◽  
Joaquim Ruiz ◽  
Myriam Zarazaga ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Amino Acid ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Mechanisms Of Resistance ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Class 1 ◽  
Human Animal

ABSTRACT Seventeen multiple-antibiotic-resistant nonpathogenic Escherichia coli strains of human, animal, and food origins showed a wide variety of antibiotic resistance genes, many of them carried by class 1 and class 2 integrons. Amino acid changes in MarR and mutations in marO were identified for 15 and 14 E. coli strains, respectively.

scholarly journals Impact of Feed Supplementation with Antimicrobial Agents on Growth Performance of Broiler Chickens, Clostridium perfringens and Enterococcus Counts, and Antibiotic Resistance Phenotypes and Distribution of Antimicrobial Resistance Determinants in Escherichia coli Isolates

2007 ◽  
Vol 73 (20) ◽  
pp. 6566-6576 ◽  
Author(s):  
Moussa S. Diarra ◽  
Fred G. Silversides ◽  
Fatoumata Diarrassouba ◽  
Jane Pritchard ◽  
Luke Masson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Broiler Chickens ◽  
Antimicrobial Agents ◽  
Growth Promoters ◽  
Feed Supplementation ◽  
E Coli ◽  
Resistance Determinants ◽  
Class 1

ABSTRACT The effects of feed supplementation with the approved antimicrobial agents bambermycin, penicillin, salinomycin, and bacitracin or a combination of salinomycin plus bacitracin were evaluated for the incidence and distribution of antibiotic resistance in 197 commensal Escherichia coli isolates from broiler chickens over 35 days. All isolates showed some degree of multiple antibiotic resistance. Resistance to tetracycline (68.5%), amoxicillin (61.4%), ceftiofur (51.3%), spectinomycin (47.2%), and sulfonamides (42%) was most frequent. The levels of resistance to streptomycin, chloramphenicol, and gentamicin were 33.5, 35.5, and 25.3%, respectively. The overall resistance levels decreased from day 7 to day 35 (P < 0.001). Comparing treatments, the levels of resistance to ceftiofur, spectinomycin, and gentamicin (except for resistance to bacitracin treatment) were significantly higher in isolates from chickens receiving feed supplemented with salinomycin than from the other feeds (P < 0.001). Using a DNA microarray analysis capable of detecting commonly found antimicrobial resistance genes, we characterized 104 tetracycline-resistant E. coli isolates from 7- to 28-day-old chickens fed different growth promoters. Results showed a decrease in the incidence of isolates harboring tet(B), bla TEM, sulI, and aadA and class 1 integron from days 7 to 35 (P < 0.01). Of the 84 tetracycline-ceftiofur-resistant E. coli isolates, 76 (90.5%) were positive for bla CMY-2. The proportions of isolates positive for sulI, aadA, and integron class 1 were significantly higher in salinomycin-treated chickens than in the control or other treatment groups (P < 0.05). These data demonstrate that multiantibiotic-resistant E. coli isolates can be found in broiler chickens regardless of the antimicrobial growth promoters used. However, the phenotype and the distribution of resistance determinants in E. coli can be modulated by feed supplementation with some of the antimicrobial agents used in broiler chicken production.

scholarly journals Integron Expression in Multidrug-Resistant Escherichia coli Isolated from House Flies within the Hospital

2018 ◽  
Vol 16 (5) ◽  
pp. 319-327
Author(s):  
Atchariya YOSBOONRUANG ◽  
Anong KIDDEE ◽  
Chatsuda BOONDUANG ◽  
Phannarai PIBALPAKDEE
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Antimicrobial Resistance ◽  
Hospital Environment ◽  
Sequencing Analysis ◽  
Class 1 Integron ◽  
House Flies ◽  
E Coli ◽  
Class 1 Integrons ◽  
Class 1

Escherichia coli is a serious cause of a variety of hospital-acquired infections and commonly contributes to the environment by house flies. Integrons, particularly class 1 integrons, are the genetic elements that play an important role in the horizontal transfer of antimicrobial resistance mechanism. This mechanism is commonly found in Enterobacteriaceae, especially E. coli. In this study, we aim to investigate the occurrence and antimicrobial resistance patterns of E. coli isolated from the house flies in Phayao hospital and to determine the gene expression of class 1 integrons in those isolates of E. coli. Totally, 70 isolates of E. coli were isolated from 60 house flies collected from the hospital. Fifty-seven of the isolates (81.43 %) were multidrug resistance (MDR) and highly resistant to b-lactams, tetracyclines, and sulfonamides. Of 57 isolates of MDR-E. coli, 20 isolates (35 %) were found to carry class 1 integron genes. Fifteen patterns of antimicrobial resistance occurred in the isolates of integron-positive E. coli. Most integron-positive E. coli isolates were resistant to 7 antimicrobials. Two isolates of these bacteria (10 %) were able to resist 13 out of 14 tested antimicrobials. Using PCR and sequencing analysis, an investigation showed that dfrA17-aadA5, dfrA12-aadA2 gene cassette was the most prevalent cassette (n = 10; 50 %) among the integron-positive E. coli isolates. Our results indicated that the presences of multidrug resistance and class 1 integrons were common in E. coli isolated from the houseflies in hospital. Therefore, screening for integron-positive E. coli from the hospital environment might be necessary for prevention of nosocomial infections.

scholarly journals Molecular characterisation of antimicrobial resistance and virulence genes in Escherichia coli strains isolated from diarrhoeic and healthy rabbits in Tunisia

2020 ◽  
Vol 28 (2) ◽  
pp. 81
Author(s):  
Raouia Ben Rhouma ◽  
Ahlem Jouini ◽  
Amira Klibi ◽  
Safa Hamrouni ◽  
Aziza Boubaker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Virulence Genes ◽  
Antimicrobial Agents ◽  
Antibiotic Resistance Genes ◽  
Virulence Gene ◽  
Diffusion Method ◽  
Class 1 Integron ◽  
E Coli ◽  
Class 1

The purpose of this study was to identify <em>Escherichia coli</em> isolates in diarrhoeic and healthy rabbits in Tunisia and characterise their virulence and antibiotic resistance genes. In the 2014-2015 period, 60 faecal samples from diarrhoeic and healthy rabbits were collected from different breeding farms in Tunisia. Susceptibility to 14 antimicrobial agents was tested by disc diffusion method and the mechanisms of gene resistance were evaluated using polymerase chain reaction and sequencing methods. Forty <em>E. coli</em> isolates were recovered in selective media. High frequency of resistance to tetracycline (95%) was detected, followed by different levels of resistance to sulphonamide (72.5%), streptomycin (62.5%), trimethoprim-sulfamethoxazole (60%), nalidixic acid (32.5%), ampicillin (37.5%) and ticarcillin (35%). <em>E. coli</em> strains were susceptible to cefotaxime, ceftazidime and imipenem. Different variants of bla<sub>TEM</sub>, <em>tet</em>, <em>sul</em> genes were detected in most of the strains resistant to ampicillin, tetracycline and sulphonamide, respectively. The presence of class 1 integron was studied in 29 sulphonamide-resistant <em>E. coli</em> strains from which 15 harboured class 1 integron with four different arrangements of gene cassettes, <em>dfrA17</em>+<em>aadA5</em> (n=9), <em>dfrA1</em> + <em>aadA1</em> (n=4), <em>dfrA12</em> + <em>addA2</em> (n=1), <em>dfrA12</em>+<em>orf</em>+<em>addA2</em> (n=1). The <em>qnrB</em> gene was detected in six strains out of 13 quinolone-resistant <em>E. coli</em> strains. Seventeen <em>E. coli</em> isolates from diarrhoeic rabbits harboured the enteropathogenic eae genes associated with different virulence genes tested (<em>fimA</em>, <em>cnf1</em>, <em>aer</em>), and affiliated to B2 (n=8) and D (n=9) phylogroups. Isolated <em>E. coli</em> strains from healthy rabbit were harbouring <em>fim A</em> and/or <em>cnf1</em> genes and affiliated to A and B1 phylogroups. This study showed that <em>E. coli</em> strains from the intestinal tract of rabbits are resistant to the widely prescribed antibiotics in medicine. Therefore, they constitute a reservoir of antimicrobial-resistant genes, which may play a significant role in the spread of antimicrobial resistance. In addition, the eae virulence gene seemed to be implicated in diarrhoea in breeder rabbits in Tunisia.

Antimicrobial Resistance, Extended-Spectrum β-Lactamase Productivity, and Class 1 Integrons in Escherichia coli from Healthy Swine

2015 ◽  
Vol 78 (8) ◽  
pp. 1442-1450 ◽  
Author(s):  
KANJANA CHANGKAEW ◽  
APIRADEE INTARAPUK ◽  
FUANGFA UTRARACHKIJ ◽  
CHIE NAKAJIMA ◽  
ORASA SUTHIENKUL ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Intestinal Flora ◽  
Class 1 Integron ◽  
Potential Health ◽  
Gene Cassettes ◽  
E Coli ◽  
Class 1 Integrons ◽  
Extended Spectrum ◽  
Class 1

Administration of antimicrobials to food-producing animals increases the risk of higher antimicrobial resistance in the normal intestinal flora of these animals. The present cross-sectional study was conducted to investigate antimicrobial susceptibility and extended-spectrum β-lactamase (ESBL)–producing strains and to characterize class 1 integrons in Escherichia coli in healthy swine in Thailand. All 122 of the tested isolates had drug-resistant phenotypes. High resistance was found to ampicillin (98.4% of isolates), chloramphenicol (95.9%), gentamicin (78.7%), streptomycin (77.9%), tetracycline (74.6%), and cefotaxime (72.1%). Fifty-four (44.3%) of the E. coli isolates were confirmed as ESBL-producing strains. Among them, blaCTX-M (45 isolates) and blaTEM (41 isolates) were detected. Of the blaCTX-M-positive E. coli isolates, 37 carried the blaCTX-M-1 cluster, 12 carried the blaCTX-M-9 cluster, and 5 carried both clusters. Sequence analysis revealed blaTEM-1, blaTEM-135, and blaTEM-175 in 38, 2, and 1 isolate, respectively. Eighty-seven (71%) of the 122isolates carried class 1 integrons, and eight distinct drug-resistance gene cassettes with seven different integron profiles were identified in 43 of these isolates. Gene cassettes were associated with resistance to aminoglycosides (aadA1, aadA2, aadA22, or aadA23), trimethoprim (dfrA5, dfrA12, or dfrA17), and lincosamide (linF). Genes encoding β-lactamases were not found in class 1 integrons. This study is the first to report ESBL-producing E. coli with a class 1 integron carrying the linF gene cassette in swine in Thailand. Our findings confirm that swine can be a reservoir of ESBL-producing E. coli harboring class 1 integrons, which may become a potential health risk if these integrons are transmitted to humans. Intensive analyses of animal, human, and environmental isolates are needed to control the spread of ESBL-producing E. coli strains.

scholarly journals Fnr-, NarP- and NarL-Dependent Regulation of Transcription Initiation from the Haemophilus influenzae Rd napF (Periplasmic Nitrate Reductase) Promoter in Escherichia coli K-12

2005 ◽  
Vol 187 (20) ◽  
pp. 6928-6935 ◽  
Author(s):  
Valley Stewart ◽  
Peggy J. Bledsoe
Keyword(s):  
Escherichia Coli ◽  
Nitrate Reductase ◽  
Haemophilus Influenzae ◽  
Control Region ◽  
Binding Sites ◽  
Transcription Initiation ◽  
Transcriptional Control ◽  
Class I ◽  
E Coli ◽  
Fnr Protein

ABSTRACT Periplasmic nitrate reductase (napFDAGHBC operon product) functions in anaerobic respiration. Transcription initiation from the Escherichia coli napF operon control region is activated by the Fnr protein in response to anaerobiosis and by the NarQ-NarP two-component regulatory system in response to nitrate or nitrite. The binding sites for the Fnr and phospho-NarP proteins are centered at positions −64.5 and −44.5, respectively, with respect to the major transcription initiation point. The E. coli napF operon is a rare example of a class I Fnr-activated transcriptional control region, in which the Fnr protein binding site is located upstream of position −60. To broaden our understanding of napF operon transcriptional control, we studied the Haemophilus influenzae Rd napF operon control region, expressed as a napF-lacZ operon fusion in the surrogate host E. coli. Mutational analysis demonstrated that expression required binding sites for the Fnr and phospho-NarP proteins centered at positions −81.5 and −42.5, respectively. Transcription from the E. coli napF operon control region is activated by phospho-NarP but antagonized by the orthologous protein, phospho-NarL. By contrast, expression from the H. influenzae napF-lacZ operon fusion in E. coli was stimulated equally well by nitrate in both narP and narL null mutants, indicating that phospho-NarL and -NarP are equally effective regulators of this promoter. Overall, the H. influenzae napF operon control region provides a relatively simple model for studying synergistic transcription by the Fnr and phospho-NarP proteins acting from class I and class II locations, respectively.

Antibiotic Resistance and Characteristics of Integrons in Escherichia coli Isolated from Penaeus vannamei at a Freshwater Shrimp Farm in Zhejiang Province, China

2019 ◽  
Vol 82 (3) ◽  
pp. 470-478 ◽  
Author(s):  
HUI CHENG ◽  
HAN JIANG ◽  
JIEHONG FANG ◽  
CHENG ZHU
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Insertion Sequence ◽  
Zhejiang Province ◽  
Resistant Bacteria ◽  
Penaeus Vannamei ◽  
Shrimp Farm ◽  
E Coli ◽  
Class 1 Integrons ◽  
Class 1

ABSTRACT Our study was conducted to investigate the antibiotic susceptibility profiles, integrons and their associated gene cassettes (GCs), and insertion sequence common regions of Escherichia coli isolates from Penaeus vannamei collected at a large-scale freshwater shrimp farm in Zhejiang Province, People's Republic of China. A total of 182 E. coli isolates were identified from 200 samples. With the exception of imipenem, isolates were most commonly resistant to β-lactams, followed by tetracylines and sulfonamides. Fifty-two (28.6%) E. coli isolates were classified as multidrug resistant, and the patterns were highly diverse, with 29 types represented. The multiple-antibiotic resistance indices of the isolates were 0.17 to 0.56; 9.3% (17) of the 182 isolates were positive for class 1 integrons, 0.5% (1 isolate) was positive for class 2 integrons, and an insertion sequence common region 1 element was found upstream of the intI1 (integrase) gene in one of the intI1-positive isolates. Four GC arrays were detected in class 1 integrons, and one GC array was detected in class 2 integrons. Although the overall prevalence of antimicrobial-resistant bacteria in P. vannamei was lower than that previously reported for poultry and livestock farms in China, concerns about the inappropriate use of antibiotics and the transmission of antimicrobial-resistant bacteria in aquaculture were raised. Alternative approaches to reducing or replacing the use of antibiotics should be further studied.

scholarly journals High quantities of multidrug-resistant Escherichia coli are present in the Machángara urban river in Quito, Ecuador

2019 ◽  
Vol 18 (1) ◽  
pp. 67-76 ◽  
Author(s):  
David Ortega-Paredes ◽  
Pedro Barba ◽  
Santiago Mena-López ◽  
Nathaly Espinel ◽  
Verónica Crespo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Index ◽  
River Pollution ◽  
Multidrug Resistant ◽  
Urban River ◽  
Health Concern ◽  
Natural Environments ◽  
E Coli ◽  
Folate Pathway ◽  
Class 1

Abstract Urban river pollution by multidrug-resistant (MDR) bacteria constitutes an important public health concern. Epidemiologically important strains of MDR Escherichia coli transmissible at the human–animal–environment interfaces are especially worrying. Quantifying and characterizing MDR E. coli at a molecular level is thus imperative for understanding its epidemiology in natural environments and its role in the spread of resistance in precise geographical areas. Cefotaxime-resistant E. coli was characterized along the watercourse of the major urban river in Quito. Our results showed high quantities of cefotaxime-resistant E. coli (2.7 × 103–5.4 × 105 CFU/100 mL). The antimicrobial resistance index (ARI) revealed the exposure of the river to antibiotic contamination, and the multiple antibiotic resistance index indicated a high risk of contamination. The blaCTX-M-15 gene was the most prevalent in our samples. Isolates also had class 1 integrons carrying aminoglycoside-modifying enzymes and folate pathway inhibitors. The isolates belonged to phylogroups A, B1 and D. Clonal complex 10 was found to be the most prevalent (ST10, ST44 and ST 167), followed by ST162, ST394 and ST46. Our study provides a warning about the high potential of the major urban river in Quito for spreading the epidemiologically important MDR E. coli.

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