Bacterial Persistence as a Phenotypic Switch
10 Sep 2004-Science (American Association for the Advancement of Science)-Vol. 305, Iss: 5690, pp 1622-1625
TL;DR: Investigating the persistence of single cells of Escherichia coli with the use of microfluidic devices found phenotypic switching occurred between normally growing cells and persister cells having reduced growth rates, leading to a simple mathematical description of the persistence switch.
Abstract: A fraction of a genetically homogeneous microbial population may survive exposure to stress such as antibiotic treatment. Unlike resistant mutants, cells regrown from such persistent bacteria remain sensitive to the antibiotic. We investigated the persistence of single cells of Escherichia coli with the use of microfluidic devices. Persistence was linked to preexisting heterogeneity in bacterial populations because phenotypic switching occurred between normally growing cells and persister cells having reduced growth rates. Quantitative measurements led to a simple mathematical description of the persistence switch. Inherent heterogeneity of bacterial populations may be important in adaptation to fluctuating environments and in the persistence of bacterial infections.
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TL;DR: Stochastic gene expression has important consequences for cellular function, being beneficial in some contexts and harmful in others, including the stress response, metabolism, development, the cell cycle, circadian rhythms, and aging.
2,471 citations
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...Interestingly, the work of Balaban et al. (2004) showed that a small persistent subpopulation exists even in untreated cultures of E. coli and that these persistent cells are generated continuously during growth....
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...Interestingly, the work of Balaban et al. (2004) showed that a...
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TL;DR: Stochasticity in gene expression can provide the flexibility needed by cells to adapt to fluctuating environments or respond to sudden stresses, and a mechanism by which population heterogeneity can be established during cellular differentiation and development.
Abstract: Genetically identical cells exposed to the same environmental conditions can show significant variation in molecular content and marked differences in phenotypic characteristics. This variability is linked to stochasticity in gene expression, which is generally viewed as having detrimental effects on cellular function with potential implications for disease. However, stochasticity in gene expression can also be advantageous. It can provide the flexibility needed by cells to adapt to fluctuating environments or respond to sudden stresses, and a mechanism by which population heterogeneity can be established during cellular differentiation and development.
2,381 citations
TL;DR: It is suggested that cancer cell populations employ a dynamic survival strategy in which individual cells transiently assume a reversibly drug-tolerant state to protect the population from eradication by potentially lethal exposures.
2,143 citations
Cites background from "Bacterial Persistence as a Phenotyp..."
...This is highly reminiscent of the properties of antibiotic-tolerant bacterial subpopulations, also called ‘‘persisters,’’ which similarly exhibit a transient ability to endure potentially lethal stresses (Balaban et al., 2004; Dhar and McKinney, 2007)....
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TL;DR: The processes that generate chemical gradients inBiofilms, the genetic and physiological responses of the bacteria as they adapt to these gradients and the techniques that can be used to visualize and measure the microscale physiological heterogeneities of bacteria in biofilms are discussed.
Abstract: Biofilms contain bacterial cells that are in a wide range of physiological states. Within a biofilm population, cells with diverse genotypes and phenotypes that express distinct metabolic pathways, stress responses and other specific biological activities are juxtaposed. The mechanisms that contribute to this genetic and physiological heterogeneity include microscale chemical gradients, adaptation to local environmental conditions, stochastic gene expression and the genotypic variation that occurs through mutation and selection. Here, we discuss the processes that generate chemical gradients in biofilms, the genetic and physiological responses of the bacteria as they adapt to these gradients and the techniques that can be used to visualize and measure the microscale physiological heterogeneities of bacteria in biofilms.
1,953 citations
Cites background from "Bacterial Persistence as a Phenotyp..."
...gov/sites/entrez?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=12319"> Escherichia coli at the single-cell leve...
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TL;DR: Global efforts are needed to promote more judicious use of prophylactic antibiotics in aquaculture as accumulating evidence indicates that unrestricted use is detrimental to fish, terrestrial animals, and human health and the environment.
Abstract: Summary
The accelerated growth of finfish aquaculture has resulted in a series of developments detrimental to the environment and human health. The latter is illustrated by the widespread and unrestricted use of prophylactic antibiotics in this industry, especially in developing countries, to forestall bacterial infections resulting from sanitary shortcomings in fish rearing. The use of a wide variety of antibiotics in large amounts, including non-biodegradable antibiotics useful in human medicine, ensures that they remain in the aquatic environment, exerting their selective pressure for long periods of time. This process has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase of antibiotic resistance in fish pathogens, in the transfer of these resistance determinants to bacteria of land animals and to human pathogens, and in alterations of the bacterial flora both in sediments and in the water column. The use of large amounts of antibiotics that have to be mixed with fish food also creates problems for industrial health and increases the opportunities for the presence of residual antibiotics in fish meat and fish products. Thus, it appears that global efforts are needed to promote more judicious use of prophylactic antibiotics in aquaculture as accumulating evidence indicates that unrestricted use is detrimental to fish, terrestrial animals, and human health and the environment.
1,947 citations
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