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A new apparatus to induce lysis of planktonic microbial cells by shock compression, cavitation and spray

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ABSTRACT

Experiments were conducted on an aqueous growth medium containing cultures of Escherichia coli (E. coli) XL1-Blue, to investigate, in a single experiment, the effect of two types of dynamic mechanical loading on cellular integrity. A bespoke shock tube was used to subject separate portions of a planktonic bacterial culture to two different loading sequences: (i) shock compression followed by cavitation, and (ii) shock compression followed by spray. The apparatus allows the generation of an adjustable loading shock wave of magnitude up to 300 MPa in a sterile laboratory environment. Cultures of E. coli were tested with this apparatus and the spread-plate technique was used to measure the survivability after mechanical loading. The loading sequence (ii) gave higher mortality than (i), suggesting that the bacteria are more vulnerable to shear deformation and cavitation than to hydrostatic compression. We present the results of preliminary experiments and suggestions for further experimental work; we discuss the potential applications of this technique to sterilize large volumes of fluid samples.

No MeSH data available.


Pressure versus time as measured at the capped end of the tube during the calibration experiment; theoretical predictions are included for comparison.
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RSOS160939F2: Pressure versus time as measured at the capped end of the tube during the calibration experiment; theoretical predictions are included for comparison.

Mentions: In figure 2, we present pressure versus time histories directly measured, as described in §2.3, in an experiment with v0 = 82 ms−1; figure 2 includes the corresponding theoretical predictions (equation (2.3)). The predictions are for the choice ρw = 1030 kg m−3 and cw = 1400 ms−1 for density and sonic speed of the bacterial broth, respectively. The measurements in figure 2 show a sudden rise in pressure to a peak value of p0 = 195 MPa, followed by an exponential decay. The predictions are in good agreement with the measurements, confirming that the design of the shock tube apparatus is adequate to perform liquid shock experiments in a controllable manner.Figure 2.


A new apparatus to induce lysis of planktonic microbial cells by shock compression, cavitation and spray
Pressure versus time as measured at the capped end of the tube during the calibration experiment; theoretical predictions are included for comparison.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383840&req=5

RSOS160939F2: Pressure versus time as measured at the capped end of the tube during the calibration experiment; theoretical predictions are included for comparison.
Mentions: In figure 2, we present pressure versus time histories directly measured, as described in §2.3, in an experiment with v0 = 82 ms−1; figure 2 includes the corresponding theoretical predictions (equation (2.3)). The predictions are for the choice ρw = 1030 kg m−3 and cw = 1400 ms−1 for density and sonic speed of the bacterial broth, respectively. The measurements in figure 2 show a sudden rise in pressure to a peak value of p0 = 195 MPa, followed by an exponential decay. The predictions are in good agreement with the measurements, confirming that the design of the shock tube apparatus is adequate to perform liquid shock experiments in a controllable manner.Figure 2.

View Article: PubMed Central - PubMed

ABSTRACT

Experiments were conducted on an aqueous growth medium containing cultures of Escherichia coli (E. coli) XL1-Blue, to investigate, in a single experiment, the effect of two types of dynamic mechanical loading on cellular integrity. A bespoke shock tube was used to subject separate portions of a planktonic bacterial culture to two different loading sequences: (i) shock compression followed by cavitation, and (ii) shock compression followed by spray. The apparatus allows the generation of an adjustable loading shock wave of magnitude up to 300 MPa in a sterile laboratory environment. Cultures of E. coli were tested with this apparatus and the spread-plate technique was used to measure the survivability after mechanical loading. The loading sequence (ii) gave higher mortality than (i), suggesting that the bacteria are more vulnerable to shear deformation and cavitation than to hydrostatic compression. We present the results of preliminary experiments and suggestions for further experimental work; we discuss the potential applications of this technique to sterilize large volumes of fluid samples.

No MeSH data available.