Investigation of the growth characteristics of E. coli using headspace analysis

2001 ◽  
pp. 191-198
Keyword(s):  
Headspace Analysis ◽  
Growth Characteristics ◽  
E Coli

scholarly journals Use of a Nonmedicated Dietary Supplement Correlates with Increased Prevalence of Streptomycin-Sulfa-Tetracycline-Resistant Escherichia coli on a Dairy Farm

2006 ◽  
Vol 72 (7) ◽  
pp. 4583-4588 ◽  
Author(s):  
Artashes R. Khachatryan ◽  
Thomas E. Besser ◽  
Dale D. Hancock ◽  
Douglas R. Call
Keyword(s):  
Escherichia Coli ◽  
Dietary Supplement ◽  
Dairy Farm ◽  
Washington State ◽  
Growth Characteristics ◽  
Control Group ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Dry Milk ◽  
Cell Densities

ABSTRACT We examined how a dietary supplement affects the prevalence of antibiotic-resistant Escherichia coli on a dairy farm in Washington State. Between 2001 and 2004 the prevalence of fecal E. coli strains resistant to streptomycin, sulfadiazine, and tetracycline (SSuT strains) declined from 59.2% to 26.1% in the calf population. In 2003 the dairy discontinued use of a dietary supplement, and we hypothesized that the decline in prevalence of SSuT strains was related to this change in management. To test this we established three treatments in which calves received no supplement, the dietary supplement with oxytetracycline, or the dietary supplement without oxytetracycline. Calves receiving either dietary supplement had a significantly higher prevalence of SSuT E. coli than the no-supplement control group (≈37% versus 20%, respectively; P = 0.03). Importantly, there was no evidence that oxytetracycline contributed to an increased prevalence of fecal SSuT E. coli. We compared the growth characteristics of SSuT and non-SSuT E. coli in LB broth enriched with either the complete dietary supplement or its individual constituents. Both the complete dietary supplement and its vitamin D component supported a significantly higher cell density of SSuT strains (P = 0.003 and P = 0.001, respectively). The dry milk and vitamin A components of the dietary supplement did not support different cell densities. These results were consistent with selection and maintenance of SSuT E. coli due to environmental components independent of antibiotic selection.

Studies To Select Appropriate Nonpathogenic Surrogate Escherichia coli Strains for Potential Use in Place of Escherichia coli O157:H7 and Salmonella in Pilot Plant Studies†

2005 ◽  
Vol 68 (2) ◽  
pp. 282-291 ◽  
Author(s):  
DENISE R. EBLEN ◽  
BASSAM A. ANNOUS ◽  
GERALD M. SAPERS
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Time Lag ◽  
Growth Characteristics ◽  
Lag Phase ◽  
Phase Duration ◽  
Pathogenic Organism ◽  
Growth And Survival ◽  
E Coli ◽  
Genes Encoding

The response of a potential nonpathogenic surrogate organism to a particular treatment should closely mimic the response of the target pathogenic organism. In this study, growth characteristics (generation time, lag phase duration, and maximum population), pH at stationary phase, and survival characteristics (level of attachment and survival on apple surfaces, resistance to hydrogen peroxide decontamination treatments, and thermal resistance at 60°C) of 15 nonpathogenic generic Escherichia coli strains and one nonpathogenic E. coli O157:H43 strain were compared with those of two E. coli O157:H7 strains and two Salmonella strains. Few differences in growth characteristics or pH at stationary phase were evident between nonpathogenic and pathogenic strains tested. However, considerably more separation among strains was seen following investigation of survival characteristics. E. coli ECRC 97.0152, which does not contain genes encoding for known virulence factors associated with E. coli O157:H7, appears to be a good surrogate candidate, with growth and survival characteristics similar to those of E. coli O157:H7 strains. The less heat-resistant surrogate strains E. coli NRRL B-766 and NRRL B-3054 and E. coli ATCC 11775, ATCC 25253, and ATCC 25922 may be used when attempting to model the heat resistance of Salmonella Montevideo G4639 and Salmonella Poona RM 2350, respectively. These surrogate strains may be useful for evaluating the efficacy of intervention steps in reducing populations of selected strains of E. coli O157:H7 and Salmonella in processing environments where these pathogens cannot be introduced.

scholarly journals New insights into the construction of wild-type Saba pig-derived Escherichia coli irp2 gene deletion strains

3 Biotech ◽  
2021 ◽  
Vol 11 (9) ◽  
Author(s):  
Bo Zhang ◽  
Hongdan Wang ◽  
Weiwei Zhao ◽  
Chunlan Shan ◽  
Chaoying Liu ◽  
...  
Keyword(s):  
Iron Uptake ◽  
Gene Editing ◽  
Gene Deletion ◽  
Growth Characteristics ◽  
Wild Type ◽  
Knock Out ◽  
E Coli ◽  
Functional Studies ◽  
Key Points ◽  
Type Strains

AbstractTo construct wild-type E. coli irp2 gene deletion strains, CRISPR/Cas9 gene editing technology was used, and the difficulty and key points of gene editing of wild-type strains were analyzed. Based on the resistance of the CRISPR/Cas9 system expression vector, 4 strains of 41 E. coli strains isolated from Saba pigs were selected as the target strains for the deletion of the irp2 gene, which were sensitive to both ampicillin and kanamycin. Then, CRISPR/Cas9 technology was combined with homologous recombination technology to construct recombinant vectors containing Cas9, sgRNA and donor sequences to knock out the irp2 gene. Finally, the absence of the irp2 gene in E. coli was further verified by iron uptake assays, iron carrier production assays and growth curve measurements. The results showed that three of the selected strains showed single base mutations and deletions (Δirp2-1, Δirp2-2 and Δirp2-3). The deletion of the irp2 gene reduced the ability of E. coli to take up iron ions and produce iron carriers, but not affect the growth characteristics of E. coli. It is shown that the CRISPR/Cas9 knock-out system constructed in this study can successfully knock out the irp2 gene of the wild-type E. coli. Our results providing new insights into genome editing in wild-type strains, which enable further functional studies of the irp2 gene in wild-type E. coli.

Optimization of Proliferation Conditions of Recombinant Escherichia coli BL21(DE3)/pET-28b(+)-aroGM150

2014 ◽  
Vol 915-916 ◽  
pp. 887-890 ◽  
Author(s):  
Rong Liang ◽  
Chang Liu ◽  
Xiu Juan Meng ◽  
Song Yi Lin
Keyword(s):  
Escherichia Coli ◽  
Genetic Engineering ◽  
Recombinant Strain ◽  
Previous Experiment ◽  
Ph Value ◽  
Plasmid Stability ◽  
Hot Spot ◽  
Growth Characteristics ◽  
E Coli ◽  
Initial Ph

Applying Escherichia coli (E. coli) for fermentation is a very common technology. However combined with genetic engineering techniques to construct the recombinant Escherichia coli and study their growth characteristics has become the hot spot now. The recombinant Escherichia coli BL21 (DE3) /pET-28baroGM150 had been constructed by our laboratory in the previous experiment. And the purpose of this study was to optimize the proliferation conditions of Escherichia coli BL21 (DE3) /pET-28baroGM150. In order to make the recombinant Escherichia coli grow stable under suitable conditions, using the density of bacteria and plasmid stability as indexes, three factors were tested including temperature, initial pH and loading volume. And the results indicated that the optimal proliferation temperature of the recombinant strain was 30°C, initial pH value was 6.5, loading volume was 150 mL medium of 1000 mL bottles.

scholarly journals Changes in growth characteristics and biofilm-forming activity of Escherichia coli with cholesterol available

2019 ◽  
Vol 36 (2) ◽  
pp. 98-101
Author(s):  
L. P. Bykova ◽  
Ya. P. Trapeznikov ◽  
A. P. Godovalov
Keyword(s):  
Escherichia Coli ◽  
Metabolic Pathways ◽  
Growth Parameters ◽  
Bactericidal Effect ◽  
Growth Characteristics ◽  
Cholesterol Concentration ◽  
Growth Phases ◽  
E Coli ◽  
Growth Properties ◽  
Peptone Broth

Aim.To assess the growth properties and formation of E. сoli biofilms with different concentrations of cholesterol available. Materials and methods. E. coli strains were cultivated in the meat-peptone broth with cholesterol added in the concentration of 3, 5, 7 and 9 mmol/l as well as in the nutrient medium without cholesterol. The growth parameters and cholesterol concentration in the samples prior to and after cultivating microorganisms and the effect of cholesterol on biofilm-forming activity of E. coli was determined. Results. Cholesterol was shown to have no bactericidal effect on E. coli, however, it is able to change the duration of growth phases of the strains that is, possibly, caused by adaptation to the presence of cholesterol and switching of metabolic pathways. Cholesterol has a stimulating effect on accumulation of biomass by the test-strain and its biofilm-forming activity. Conclusions. In the study performed, the ability of E. coli to metabolize human cholesterol was shown.

Growth of Escherichia coli O157:H7, Salmonella Typhimurium DT104, and Listeria monocytogenes in Dark Cutting Beef at 10 or 22° C†

2002 ◽  
Vol 65 (1) ◽  
pp. 196-198 ◽  
Author(s):  
C. A. HOOPER-KINDER ◽  
P. M. DAVIDSON ◽  
S. K. DUCKETT
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Foodborne Pathogens ◽  
Ground Beef ◽  
Growth Characteristics ◽  
Escherichia Coli O157 ◽  
E Coli

An experiment was conducted to determine the effects of the dark, firm, and dry (DFD) condition of beef on growth of the foodborne pathogens Escherichia coli O157:H7, Salmonella Typhimurium DT104, and Listeria monocytogenes Scott A in ground beef. Longissimus muscles from a DFD carcass (pH = 6.45) and normal carcass (N; pH = 5.64) were ground and samples obtained (100 and 0% DFD, respectively). Equal amounts of the 0 and 100% DFD ground samples were mixed to obtain 50% DFD samples. Inoculated 0, 50, and 100% DFD samples were packaged into oxygen-permeable overwrap and stored at 10°C for E. coli O157:H7, Salmonella Typhimurium DT104, and L. monocytogenes Scott A or at 22°C for E. coli O157:H7. Growth characteristics of E. coli O157:H7, Salmonella Typhimurium DT104, and L. monocytogenes Scott A did not differ (P > 0.05) between 0 and 100% DFD. Results indicated that the DFD beef used in this study was no more susceptible to growth of E. coli O157:H7, Salmonella Typhimurium, or L. monocytogenes Scott A than N beef.

scholarly journals Comparative study on growth and morphological characteristics of a wild type strain Rhizobium spp. (RCA-220) and a genetically engineered E. coli BL21

2014 ◽  
Vol 20 ◽  
pp. 75-82
Author(s):  
MM Rahman ◽  
M Salah Uddin ◽  
S Zaman ◽  
MA Saleh ◽  
AE Ekram ◽  
...  
Keyword(s):  
Growth Rate ◽  
Carbon Source ◽  
Salt Concentration ◽  
Type Strain ◽  
Wild Type Strain ◽  
Genetically Modified ◽  
Growth Characteristics ◽  
Wild Type ◽  
E Coli ◽  
Rhizobium Spp

Context: Comparison between a wild type strain Rhizobium spp. (RCA-220) and a genetically modified strain E. coli BL21 in context of growth features. Objective: To observe the comparative growth characteristics of a genetically modified E. coli BL21 and an isolated wild type strain Rhizobium spp. (RCA-220). Materials and Methods: Different kinds of investigations were accomplished in both Luria-Bertani (LB) liquid and semi-solid media to observe the growth and maintenance of these strains. For the isolation of Rhizobium spp. selective Yeast Extract Manitol Agar (YEMA) was used. Colony morphology, pH, temperature, carbon source, salt concentration and light were taken under consideration and optimized for growth characteristics. Results: For the strain E. coli BL21, the maximum growth rate was 1.9 at incubation time 72 h, pH 7.2, temperature 37°C (optimized) while for Rhizobium spp. the growth rate was significantly higher (OD 2) at pH 6.8, temperature 28°C (optimized). Among all used carbon sources, strains grown in the medium supplemented with peptone showed rapid and good performance. So, peptone was proved as the best carbon source for both strains. The maximum growths of these strains were observed at 0g/100ml NaCl salt concentration. RCA-220 strain was comparatively more tolerable to salt than E. coli BL21 strain. In this work, E. coli BL21 showed rapid and good performance in presence of light while Rhizobium spp. showed better performance in absence of light. Statistical analysis showed that the growth rate of Rhizobium spp. was significantly higher than E. coli BL21. Conclusion: From the experimental results, it can be concluded that naturally obtained microbial strains were stable and could tolerate any stress condition where the modified strains lose their growth capability and the overall growth performances were reduced or slowed down than the wild type strain. DOI: http://dx.doi.org/10.3329/jbs.v20i0.17718 J. bio-sci.  20:  75-82, 2012

scholarly journals Volatile atmospheric pressure chemical ionisation mass spectrometry headspace analysis of E. coli and S. aureus

2021 ◽  
Author(s):  
Kerry Rosenthal ◽  
Eugenie Hunsicker ◽  
Elizabeth Ratcliffe ◽  
Martin R. Lindley ◽  
Joshua Leonard ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Atmospheric Pressure ◽  
Bacterial Species ◽  
Headspace Analysis ◽  
E Coli ◽  
Improve Treatment ◽  
Ionisation Mass Spectrometry ◽  
Pressure Chemical ◽  
Chemical Ionisation ◽  
Ionisation Mass

Identifying the characteristics of bacterial species can improve treatment outcomes and mass spectrometry methods have been shown to be capable of identifying biomarkers of bacterial species.

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