scholarly journals The Effects of Colicin Production Rates on Allelopathic Interactions in Escherichia coli Populations

2019 ◽  
Vol 7 (11) ◽  
pp. 564 ◽  
Author(s):  
Ghazaryan ◽  
Giladi ◽  
Gillor
Keyword(s):  
Escherichia Coli ◽  
Production Rates ◽  
Competitive Fitness ◽  
Living Space ◽  
Bacteriocin Producer ◽  
Unstructured Environment ◽  
Beneficial Traits ◽  
Allelopathic Interactions ◽  
Sensitive Population ◽  
Space Competition

Allelopathic interactions mediated by bacteriocins production serve microorganisms in the never-ending battle for resources and living space. Competition between the bacteriocin producer and sensitive populations results in the exclusion of one or the other depending on their initial frequencies, the structure of their habitat, their community density and their nutrient availability. These interactions were extensively studied in bacteriocins produced by Escherichia coli, the colicins. In spatially structured environments where interactions are local, colicin production has been shown to be advantageous to the producer population, allowing them to compete even when initially rare. Yet, in a well-mixed, unstructured environment where interactions are global, rare producer populations cannot invade a common sensitive population. Here we are showing, through an experimental model, that colicin-producers can outcompete sensitive and producer populations when the colicin production rates are enhanced. In fact, colicin production rates were proportional to the producer competitive fitness and their overall success in out-competing opponents when invading at very low initial frequencies. This ability of rare populations to invade established communities maintains diversity and allows the dispersal of beneficial traits.

scholarly journals Escherichia coli Competence Gene Homologs Are Essential for Competitive Fitness and the Use of DNA as a Nutrient

2006 ◽  
Vol 188 (11) ◽  
pp. 3902-3910 ◽  
Author(s):  
Vyacheslav Palchevskiy ◽  
Steven E. Finkel
Keyword(s):  
Escherichia Coli ◽  
Sole Source ◽  
Extracellular Dna ◽  
Nutrient Source ◽  
Genetic Competence ◽  
Exogenous Dna ◽  
Competitive Fitness ◽  
E Coli ◽  
Widespread Phenomenon

ABSTRACT Natural genetic competence is the ability of cells to take up extracellular DNA and is an important mechanism for horizontal gene transfer. Another potential benefit of natural competence is that exogenous DNA can serve as a nutrient source for starving bacteria because the ability to “eat” DNA is necessary for competitive survival in environments containing limited nutrients. We show here that eight Escherichia coli genes, identified as homologs of com genes in Haemophilus influenzae and Neisseria gonorrhoeae, are necessary for the use of extracellular DNA as the sole source of carbon and energy. These genes also confer a competitive advantage to E. coli during long-term stationary-phase incubation. We also show that homologs of these genes are found throughout the proteobacteria, suggesting that the use of DNA as a nutrient may be a widespread phenomenon.

scholarly journals Fitness, Stress Resistance, and Extraintestinal Virulence in Escherichia coli

2013 ◽  
Vol 81 (8) ◽  
pp. 2733-2742 ◽  
Author(s):  
Alexandre Bleibtreu ◽  
Pierre-Alexis Gros ◽  
Cédric Laouénan ◽  
Olivier Clermont ◽  
Hervé Le Nagard ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Stress Response ◽  
Mouse Model ◽  
Stress Resistance ◽  
Maximum Growth ◽  
Competitive Fitness ◽  
Content Type ◽  
General Stress Response ◽  
E Coli

ABSTRACTThe extraintestinal virulence ofEscherichia coliis dependent on numerous virulence genes. However, there is growing evidence for a role of the metabolic properties and stress responses of strains in pathogenesis. We assessed the respective roles of these factors in strain virulence by developing phenotypic assays for measuringin vitroindividual and competitive fitness and the general stress response, which we applied to 82 commensal and extraintestinal pathogenicE. colistrains previously tested in a mouse model of sepsis. Individual fitness properties, in terms of maximum growth rates in various media (Luria-Bertani broth with and without iron chelator, minimal medium supplemented with gluconate, and human urine) and competitive fitness properties, estimated as the mean relative growth rate per generation in mixed cultures with a reference fluorescentE. colistrain, were highly diverse between strains. The activity of the main general stress response regulator, RpoS, as determined by iodine staining of the colonies, H2O2resistance, andrpoSsequencing, was also highly variable. No correlation between strain fitness and stress resistance and virulence in the mouse model was found, except that the maximum growth rate in urine was higher for virulent strains. Multivariate analysis showed that the number of virulence factors was the only independent factor explaining the virulence in mice. At the species level, growth capacity and stress resistance are heterogeneous properties that do not contribute significantly to the intrinsic virulence of the strains.

scholarly journals Microbial evolution in a simple unstructured environment: genetic differentiation in Escherichia coli.

Genetics ◽  
1994 ◽  
Vol 137 (4) ◽  
pp. 903-917 ◽  
Author(s):  
R F Rosenzweig ◽  
R R Sharp ◽  
D S Treves ◽  
J Adams
Keyword(s):  
Escherichia Coli ◽  
Structural Changes ◽  
Specific Growth ◽  
Microbial Evolution ◽  
Kinetics Analysis ◽  
Acetyl Coenzyme A ◽  
Unstructured Environment ◽  
Single Clone ◽  
Glycerol Uptake ◽  
Specific Growth Rates

Abstract Populations of Escherichia coli initiated with a single clone and maintained for long periods in glucose-limited continuous culture, become polymorphic. In one population, three clones were isolated and by means of reconstruction experiments were shown to be maintained in stable polymorphism, although they exhibited substantial differences in maximum specific growth rates and in glucose uptake kinetics. Analysis of these three clones revealed that their stable coexistence could be explained by differential patterns of the secretion and uptake of two alternative metabolites acetate and glycerol. Regulatory (constitutive and null) mutations in acetyl-coenzyme A synthetase accounted for different patterns of acetate secretion and uptake seen. Altered patterns in glycerol uptake are most likely explained by mutations which result in quantitative differences in the induction of the glycerol regulon and/or structural changes in glycerol kinase that reduce allosteric inhibition by effector molecules associated with glycolysis. The evolution of resource partitioning, and consequent polymorphisms which arise may illustrate incipient processes of speciation in asexual organisms.

scholarly journals Comparative Pathogenicity of Wildlife and Bovine Escherichia coli O157:H7 Strains in Experimentally Inoculated Neonatal Jersey Calves

2018 ◽  
Vol 5 (4) ◽  
pp. 88
Author(s):  
Elizabeth Antaki-Zukoski ◽  
Xunde Li ◽  
Patricia Pesavento ◽  
Tran Nguyen ◽  
Bruce Hoar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Living Space ◽  
Animal Pathogens ◽  
Colonization Patterns ◽  
Neonatal Calves ◽  
Descending Colon ◽  
Highly Virulent

Shiga toxin-producing Escherichia coli, like E. coli O157:H7, are important human and animal pathogens. Naturally-acquired E. coli O157:H7 infections occur in numerous species but, particularly, cattle have been identified as a significant reservoir for human cases. E. coli O157:H7 are isolated from a number of domestic and wild animals, including rodents that share a living space with cattle. These Shiga toxin-producing E. coli O157:H7 strains can be highly virulent in humans, but little is known about the sequelae of interspecies transfer. In a group of neonatal calves, we determined the differences in colonization patterns and lesions associated with infection using either a wildlife or bovine E. coli O157:H7 strain. In calves challenged with the wildlife E. coli O157:H7 strain, the large (descending) colon was solely colonized, which differed substantially from the calves inoculated with the bovine E. coli O157:H7 strain, where the spiral colon was the principal target of infection. This study also demonstrated that while both interspecies- and intraspecies-derived E. coli O157:H7 can infect young calves, the distribution and severity differs.

scholarly journals Competition among Escherichia coli Strains for Space and Resources

2018 ◽  
Vol 5 (4) ◽  
pp. 93 ◽  
Author(s):  
Sarah-Jo Paquette ◽  
Rahat Zaheer ◽  
Kim Stanford ◽  
James Thomas ◽  
Tim Reuter
Keyword(s):  
Escherichia Coli ◽  
Food Industry ◽  
Mitigation Strategy ◽  
Mitigation Strategies ◽  
Natural Environments ◽  
Emerging Pathogens ◽  
Competitive Fitness ◽  
E Coli ◽  
Physical Barriers ◽  
Global Concern

Shiga toxin-producing Escherichia coli (STEC) are a subgroup of E. coli causing human diseases. Methods to control STEC in livestock and humans are limited. These and other emerging pathogens are a global concern and novel mitigation strategies are required. Habitats populated by bacteria are subjected to competition pressures due to limited space and resources but they use various strategies to compete in natural environments. Our objective was to evaluate non-pathogenic E. coli strains isolated from cattle feces for their ability to out-compete STEC. Competitive fitness of non-pathogenic E. coli against STEC were assessed in competitions using liquid, agar, and nutrient limiting assays. Winners were determined by enumeration using O-serogroup specific quantitative PCR or a semi-quantitative grading. Initial liquid competitions identified two strong non-pathogenic competitors (O103F and O26E) capable of eliminating various STEC including O157 and O111. The strain O103F was dominant across permeable physical barriers for all tested E. coli and STEC strains indicating the diffusion of antimicrobial molecules. In direct contact and even with temporal disadvantages, O103F out-competed STEC O157E. The results suggest that O103F or the diffusible molecule(s) it produces have a potential to be used as an alternative STEC mitigation strategy, either in medicine or the food industry.

scholarly journals Microbial factories: Monitoring vitamin B2 production by Escherichia coli in microfluidic cultivation chambers

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Petra Juskova ◽  
Steven Schmitt ◽  
Lucas Armbrecht ◽  
Petra S Dittrich
Keyword(s):  
Escherichia Coli ◽  
Growth Conditions ◽  
Vitamin B2 ◽  
Production Rates ◽  
Microbial Cells ◽  
Biotechnological Products ◽  
Production Host ◽  
Standard Production ◽  
Over Time

Microbial cells represent a standard production host for various important biotechnological products. Production yields can be increased by optimising strains, growth conditions and understanding deviations in production rates over time...

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