DNA supercoiling and bacterial adaptation: Thermotolerance and thermoresistance

Tse‐Dinh, Yuk‐Ching; Qi, Honglan; Menzel, Rolf

doi:10.1016/s0966-842x(97)01080-9

Cited by 79 publications

(57 citation statements)

References 30 publications

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“…Nevertheless, environmental factors such as high temperature and high osmolarity, which are known to induce changes in DNA topology and regulation of gene expression (8,28), also affect bacterial motility in various microorganisms, such as H. pylori (27) and Y. enterocolitica (20). The loss of motility in E. coli in the presence of novobiocin, a gyrase inhibitor (22), further supports a link between the DNA supercoiling level and motility regulation.…”

Section: Discussionmentioning

confidence: 98%

“…A link between DNA topology and regulation of gene expression in response to environmental cues has been proposed (28). In particular, a reduction in motility has been observed in E. coli in the presence of DNA gyrase inhibitors, suggesting the involvement of DNA supercoiling in the regulation of bacterial motility (22).…”

Section: Af081587] and Erwinia Carotovora [Genbank Accession No Af1mentioning

confidence: 99%

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Control of Bacterial Motility by Environmental Factors in Polarly Flagellated and Peritrichous Bacteria Isolated from Lake Baikal

Soutourina

Semenova

Парфенова

et al. 2001

Appl Environ Microbiol

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Despite numerous studies on bacterial motility, little is known about the regulation of this process by environmental factors in natural isolates. In this study we investigated the control of bacterial motility in response to environmental parameters in two strains isolated from the natural habitat of Lake Baikal. Morphological characterization, carbon source utilization, fermentation analysis, and sequence comparison of 16S rRNA genes showed that these strains belong to two distinct genera, i.e., Enterobacter and Pseudomonas; they were named strains 22 and Y1000, respectively. Both strains swarmed at 25°C and remained motile at low temperatures (4°C), especially the Pseudomonas strain, which further supports the psychrotrophic characteristics of this strain. In contrast, a strong inhibition of motility was observed at above 30°C and with a high NaCl concentration. The existence of flagellar regulatory proteins FlhDC and FleQ was demonstrated in Enterobacter strain 22 and Pseudomonas strain Y1000, respectively, and environmental conditions reduced the expression of the structural genes potentially located at the first level in the flagellar cascade in both organisms. Finally, as in Enterobacter strain 22, a strong reduction in the transcription of the master regulatory gene fleQ was observed in Pseudomonas strain Y1000 in the presence of novobiocin, a DNA gyrase inhibitor, suggesting a link between DNA supercoiling and motility control by environmental factors. Thus, striking similarities observed in the two organisms suggest that these processes have evolved toward a similar regulatory mechanism in polarly flagellated and laterally flagellated (peritrichous) bacteria.Microorganisms are able to survive under a wide range of environmental conditions (e.g., osmolarity, temperature, and nutrient availability) by rapidly adapting their structure and physiology. These mechanisms are based on the existence of multiple regulatory systems in which gene expression is controlled in a coordinate manner in response to environmental stimuli. One example of such a complex process is the regulation of motility and chemotaxis in bacteria (16).More than 80% of the known bacterial species are motile by means of flagella (18). The structure and arrangement of flagella differ from species to species and seem to be related to the specific environments in which the cells live (29). Flagella can be arranged on the cell body in a variety of configurations, including single polar, multiple polar, and many peritrichous (or lateral) configurations. Motility by means of flagella is thought to provide a specific advantage for a bacterium (18), because it helps the bacterium to reach the most favorable environment and to successfully compete with other microorganisms. However, the cost of maintenance of a flagellar motility system is high for bacteria (about 2% of biosynthetic energy expenditure in Escherichia coli) due to the number of genes and the energy required for flagellum synthesis and functioning. As a result, the flagellar system i...

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Section: Discussionmentioning

confidence: 98%

Section: Af081587] and Erwinia Carotovora [Genbank Accession No Af1mentioning

confidence: 99%

Control of Bacterial Motility by Environmental Factors in Polarly Flagellated and Peritrichous Bacteria Isolated from Lake Baikal

Soutourina

Semenova

Парфенова

et al. 2001

Appl Environ Microbiol

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“…This second pathway may be mediated by a regulatory protein whose synthesis is stress specific or by the degree of local DNA supercoiling at the promoter. In some bacteria, the degree of local superhelicity can be altered in response to low pH, high temperature, and increased osmolarity, which in turn may alter the level of transcription from certain promoters (2,3,5,15,24,27,30,48).…”

Section: Discussionmentioning

confidence: 99%

RscA, a Member of the MDR1 Family of Transporters, Is Repressed by CovR and Required for Growth ofStreptococcus pyogenesunder Heat Stress

et al. 2006

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The ability of Streptococcus pyogenes (group A streptococcus [GAS]) to respond to changes in environmental conditions is essential for this gram-positive organism to successfully cause disease in its human host. The two-component system CovRS controls expression of about 15% of the GAS genome either directly or indirectly. In most operons studied, CovR acts as a repressor. We previously linked CovRS to the GAS stress response by showing that the sensor kinase CovS is required to inactivate the response regulator CovR so that GAS can grow under conditions of heat, acid, and salt stress. Here, we sought to identify CovR-repressed genes that are required for growth under stress. To do this, global transcription profiles were analyzed by microarrays following exposure to increased temperature (40°C) and decreased pH (pH 6.0). The CovR regulon in an M type 6 strain of GAS was also examined by global transcriptional analysis. We identified a gene, rscA (regulated by stress and Cov), whose transcription was confirmed to be repressed by CovR and activated by heat and acid. RscA is a member of the MDR1 family of ABC transporters, and we found that it is required for growth of GAS at 40°C but not at pH 6.0. Thus, for GAS to grow at 40°C, CovR repression must be alleviated so that rscA can be transcribed to allow the production of this potential exporter. Possible explanations for the thermoprotective role of RscA in this pathogen are discussed.

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“…Moreover, the involvement of DNA supercoiling has been proposed, for example, to explain the regulation by H-NS of osmotically regulated genes (Higgins et al, 1988), stringently controlled bacterial promoters (Johansson et al, 2000) or virulence gene expression in Shigella flexneri (Dorman et al, 2001). On the other hand, various environmental conditions are also known to affect the level of DNA supercoiling, even though a cause-and-effect relationship has not yet been established (Higgins et al, 1988 ;Tse-Dinh et al, 1997). It has been proposed that a direct effect of environmental signals on promoter architecture, and then transcription, through influencing the interaction of architectural proteins with DNA, might be an important concept in understanding the environmental regulation of gene expression in bacteria (Jordi et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

Regulation of bacterial motility in response to low pH in Escherichia coli: the role of H-NS protein

et al. 2002

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The effect of detrimental conditions on bacterial motility in Escherichia coli was investigated. Expression profiling of mutant E. coli strains by DNA arrays and analysis of phenotypic traits demonstrated that motility and low-pH resistance are coordinately regulated. Analysis of transcriptional fusions suggests that bacterial motility in response to an acidic environment is mediated via the control by H-NS of flhDC expression. Moreover, the results suggested that the presence of an extended mRNA 5' end and DNA topology are required in this process. Finally, the presence of a similar regulatory region in several Gram-negative bacteria implies that this mechanism is largely conserved.

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DNA supercoiling and bacterial adaptation: Thermotolerance and thermoresistance

Cited by 79 publications

References 30 publications

Control of Bacterial Motility by Environmental Factors in Polarly Flagellated and Peritrichous Bacteria Isolated from Lake Baikal

Control of Bacterial Motility by Environmental Factors in Polarly Flagellated and Peritrichous Bacteria Isolated from Lake Baikal

RscA, a Member of the MDR1 Family of Transporters, Is Repressed by CovR and Required for Growth ofStreptococcus pyogenesunder Heat Stress

Regulation of bacterial motility in response to low pH in Escherichia coli: the role of H-NS protein

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