Involvement of rpoS in the survival of Escherichia coli in the viable but non-culturable state
| Autor: | Maria M. Lleo, Marzia Boaretti, Barbara Bonato, Pietro Canepari, Caterina Signoretto |
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| Rok vydání: | 2003 |
| Předmět: |
Population
Mutant Sigma Factor Guanosine Tetraphosphate Biology medicine.disease_cause Microbiology chemistry.chemical_compound Sodium pyruvate Bacterial Proteins Escherichia coli medicine Animals Humans Viability assay education Gene Ecology Evolution Behavior and Systematics education.field_of_study Escherichia coli Proteins equipment and supplies biology.organism_classification chemistry bacteria rpoS Bacteria |
| Zdroj: | Environmental Microbiology. 5:986-996 |
| ISSN: | 1462-2920 1462-2912 |
| DOI: | 10.1046/j.1462-2920.2003.00497.x |
| Popis: | When exposed to stress-provoking environmental conditions such as those of ground waters, many medically important bacteria have been shown to be capable of activating a survival strategy known as the viable but non-culturable (VBNC) state. In this state bacteria are no longer culturable on conventional growth media, but the cells maintain their viability and pathogenicity genes/factors and can start dividing again, in a part of the cell population, upon restoration of favourable environmental conditions. Little is known about the genetic mechanisms underlying the VBNC state. In this study we show evidence of involvement of the rpoS gene in persistence of Escherichia coli in the VBNC state. The kinetics of entry into the non-culturable state and duration of cell viability were measured in two E. coli mutants carrying an inactivated rpoS gene and compared with those of the parents. For these experiments, laboratory microcosms consisting of an artificial oligotrophic medium incubated at 4 degrees C were used. The E. coli parental strains reached the non-culturable state in 33 days when the plate counts were evaluated on Luria-Bertani agar containing sodium pyruvate, whereas cells of the rpoS mutants lost their culturability in only 21 days. Upon reaching unculturability the parents yielded respiring cells and cells with intact membranes for at least the next three weeks and resuscitation was allowed during this time. In contrast, the RpoS- mutant cells demonstrated intact membranes for only two weeks and a very restricted ( |
| Databáze: | OpenAIRE |
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