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Agitation down-regulates immunoglobulin binding protein EibG expression in Shiga toxin-producing Escherichia coli (STEC).

Kuczius T, Zhang W, Merkel V, Mellmann A, Tarr PI, Karch H - PLoS ONE (2015)

Bottom Line: EibG proteins as well as corresponding mRNA were highly expressed under static growth conditions while shearing stress created by agitation during growth repressed protein synthesis.High and low EibG expression was reversible indicating a process with up- and down-regulation of the protein expression.Our findings indicate that shear stress represses EibG expression and might reduce bacterial attachments to cells and surfaces.

View Article: PubMed Central - PubMed

Affiliation: Institute for Hygiene, Westfälische Wilhelms-University and University Hospital Münster, Robert Koch-Strasse 41, 48149, Münster, Germany.

ABSTRACT
Shiga toxin (Stx)-producing Escherichia coli (STEC) carrying eibG synthesize Escherichia coli immunoglobulin binding protein (EibG). EibG nonspecifically binds to immunoglobulins and tends to aggregate in multimers but is poorly expressed in wild-type strains. To study synthesis of the proteins and their regulation in the pathogens, we identified natural growth conditions that increased EibG synthesis. EibG proteins as well as corresponding mRNA were highly expressed under static growth conditions while shearing stress created by agitation during growth repressed protein synthesis. Further regulation effects were driven by reduced oxygen tension, and pH up-regulated EibG expression, but to a lesser extent than growth conditions while decreased temperature down-regulated EibG. Bacteria with increased EibG expression during static growth conditions showed a distinct phenotype with chain formation and biofilm generation, which disappeared with motion. High and low EibG expression was reversible indicating a process with up- and down-regulation of the protein expression. Our findings indicate that shear stress represses EibG expression and might reduce bacterial attachments to cells and surfaces.

No MeSH data available.


Related in: MedlinePlus

Reduced oxygen up-regulates EibG expression.Strains 2875/96 and 0520/99 were inoculated into agitated (+) or static conditions (-) in jars under aerobic, microaerophilic and anaerobic conditions at 37°C for 18h. After cell harvesting, proteins were loaded and immunoblotted. (A) EibG proteins were visualized by chemiluminescence and (B) EibG signals were densitometrically quantified and are reported as computer internal units. Values are typical of those from repeated growth conditions and independent gel runs. (C) Cells were harvested from LB plates. Proteins of 5 and 15 μg per lane were loaded for 2875/96 and 0520/99, respectively, and EibG proteins were immunologically detected.
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pone.0119583.g005: Reduced oxygen up-regulates EibG expression.Strains 2875/96 and 0520/99 were inoculated into agitated (+) or static conditions (-) in jars under aerobic, microaerophilic and anaerobic conditions at 37°C for 18h. After cell harvesting, proteins were loaded and immunoblotted. (A) EibG proteins were visualized by chemiluminescence and (B) EibG signals were densitometrically quantified and are reported as computer internal units. Values are typical of those from repeated growth conditions and independent gel runs. (C) Cells were harvested from LB plates. Proteins of 5 and 15 μg per lane were loaded for 2875/96 and 0520/99, respectively, and EibG proteins were immunologically detected.

Mentions: As shown, EibG proteins are highly regulated in expression with high levels after static growth and very low levels after growth conditions with agitation. To determine if shear stress plays the only major role for the up- and down-regulation we analyzed the influence of oxygen in the next experimental set-up, because bacteria grown under agitated conditions are exposed to higher oxygen concentration than bacteria grown under static conditions. Cultures of 2875/96 (α-type) and 0520/99 (γ-type) were inoculated with and without agitation under aerobic, microaerophilic and anaerobic conditions (Fig. 5). Bacteria produced high EibG signals under aerobic and microaerophilic growth without agitation while faint but visible bands were detected with shaking (Fig. 5A). Interestingly, aeration may have an appreciable influence on the EibG expression level under agitation, as protein signal intensities were considerably higher under microaerophilic than under aerobic growth proven by signal quantification (Fig. 5B). In contrast, EibG expression was at the detection limit in each case when cultures were inoculated under anaerobic growth independent on static or shaking conditions. To verify this regulatory effect we cultivated the strains on plates followed by aerobic, microaerophilic and anaerobic inoculation (Fig. 5C). Increased EibG expression was observed under microaerophilic growth conditions, less intense signals were detected with aerobic growth, and only very faint bands were visible with anaerobic growth.


Agitation down-regulates immunoglobulin binding protein EibG expression in Shiga toxin-producing Escherichia coli (STEC).

Kuczius T, Zhang W, Merkel V, Mellmann A, Tarr PI, Karch H - PLoS ONE (2015)

Reduced oxygen up-regulates EibG expression.Strains 2875/96 and 0520/99 were inoculated into agitated (+) or static conditions (-) in jars under aerobic, microaerophilic and anaerobic conditions at 37°C for 18h. After cell harvesting, proteins were loaded and immunoblotted. (A) EibG proteins were visualized by chemiluminescence and (B) EibG signals were densitometrically quantified and are reported as computer internal units. Values are typical of those from repeated growth conditions and independent gel runs. (C) Cells were harvested from LB plates. Proteins of 5 and 15 μg per lane were loaded for 2875/96 and 0520/99, respectively, and EibG proteins were immunologically detected.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4352079&req=5

pone.0119583.g005: Reduced oxygen up-regulates EibG expression.Strains 2875/96 and 0520/99 were inoculated into agitated (+) or static conditions (-) in jars under aerobic, microaerophilic and anaerobic conditions at 37°C for 18h. After cell harvesting, proteins were loaded and immunoblotted. (A) EibG proteins were visualized by chemiluminescence and (B) EibG signals were densitometrically quantified and are reported as computer internal units. Values are typical of those from repeated growth conditions and independent gel runs. (C) Cells were harvested from LB plates. Proteins of 5 and 15 μg per lane were loaded for 2875/96 and 0520/99, respectively, and EibG proteins were immunologically detected.
Mentions: As shown, EibG proteins are highly regulated in expression with high levels after static growth and very low levels after growth conditions with agitation. To determine if shear stress plays the only major role for the up- and down-regulation we analyzed the influence of oxygen in the next experimental set-up, because bacteria grown under agitated conditions are exposed to higher oxygen concentration than bacteria grown under static conditions. Cultures of 2875/96 (α-type) and 0520/99 (γ-type) were inoculated with and without agitation under aerobic, microaerophilic and anaerobic conditions (Fig. 5). Bacteria produced high EibG signals under aerobic and microaerophilic growth without agitation while faint but visible bands were detected with shaking (Fig. 5A). Interestingly, aeration may have an appreciable influence on the EibG expression level under agitation, as protein signal intensities were considerably higher under microaerophilic than under aerobic growth proven by signal quantification (Fig. 5B). In contrast, EibG expression was at the detection limit in each case when cultures were inoculated under anaerobic growth independent on static or shaking conditions. To verify this regulatory effect we cultivated the strains on plates followed by aerobic, microaerophilic and anaerobic inoculation (Fig. 5C). Increased EibG expression was observed under microaerophilic growth conditions, less intense signals were detected with aerobic growth, and only very faint bands were visible with anaerobic growth.

Bottom Line: EibG proteins as well as corresponding mRNA were highly expressed under static growth conditions while shearing stress created by agitation during growth repressed protein synthesis.High and low EibG expression was reversible indicating a process with up- and down-regulation of the protein expression.Our findings indicate that shear stress represses EibG expression and might reduce bacterial attachments to cells and surfaces.

View Article: PubMed Central - PubMed

Affiliation: Institute for Hygiene, Westfälische Wilhelms-University and University Hospital Münster, Robert Koch-Strasse 41, 48149, Münster, Germany.

ABSTRACT
Shiga toxin (Stx)-producing Escherichia coli (STEC) carrying eibG synthesize Escherichia coli immunoglobulin binding protein (EibG). EibG nonspecifically binds to immunoglobulins and tends to aggregate in multimers but is poorly expressed in wild-type strains. To study synthesis of the proteins and their regulation in the pathogens, we identified natural growth conditions that increased EibG synthesis. EibG proteins as well as corresponding mRNA were highly expressed under static growth conditions while shearing stress created by agitation during growth repressed protein synthesis. Further regulation effects were driven by reduced oxygen tension, and pH up-regulated EibG expression, but to a lesser extent than growth conditions while decreased temperature down-regulated EibG. Bacteria with increased EibG expression during static growth conditions showed a distinct phenotype with chain formation and biofilm generation, which disappeared with motion. High and low EibG expression was reversible indicating a process with up- and down-regulation of the protein expression. Our findings indicate that shear stress represses EibG expression and might reduce bacterial attachments to cells and surfaces.

No MeSH data available.


Related in: MedlinePlus