1. Analyzing Thermal Stability of Cell Membrane of Salmonella Using Time-Multiplexed Impedance Sensing 
Aida Ebrahimi, Laszlo N. Csonka, Muhammad A. Alam 
Biophysical Journal 
Volume 114, Issue 3, Pages (February 2018)
DOI: /j.bpj
Copyright © 2017 Biophysical Society Terms and Conditions

2. Figure 1
Schematic of the experimental steps, including the heating profiles: (a) ramp versus (b) pulse shocks, with the former transferring less energy to cells at a given heating time. As indicated, cell temperature, Tcell, is fitted with a thermal time constant, τ, which is different for ramp and pulse heating. (c) Shown here is an optical image of the sensing chip, with an array of sample droplets. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

3. Figure 2
Droplet conductance, Y, during evaporation of droplets of (a) WT, (b) HR-B, and (c) HR-A with ramp heating for tH = 12 min, exposed to different TH indicated by the legends. In each case, Y0 refers to the conductance of the corresponding working culture. As indicated by the red arrows, in contrast to the HR cells, the conductance increases gradually with TH in WT samples. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

4. Figure 3
The time-averaged differential conductance, 〈ΔY〉t∗, versus TH for samples exposed to ramp shock at (a) tH = 4 min ± 15% and (c) tH = 12 min ± 15%, with the corresponding colony counting results shown in (b) and (d). The dashed lines in (b) and (d) indicate 99% decrease in viability (ρ). The error bars are the SE, i.e., std/j, where std is the SD from mean with j = 9 data points, obtained from three sets of experiments. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

5. Figure 4
(a) The time-averaged differential conductance, 〈ΔY〉t∗, for WT and HR-B samples exposed to ramp shock at TH = 53°C or different values of tH. The arrow indicates that detectable conductance increase is observed after 8 min heating under ramp shock at TH = 53°C. (b) Given here are the colony counting results of the samples presented in (a). The dashed line indicates 99% decrease in viability (ρ). The error bars are the SE, i.e., std/j, where std is the SD from mean with j = 9 data points, obtained from three sets of experiments. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

6. Figure 5
Comparison between distribution of the fluorescence intensity of PI dye in WT and HR-B samples exposed to ramp shock for tH = 5 min, at (a) TH = 50°C and (b) TH = 53°C. The mean value of the histogram (mean of PI intensity) for WT is larger than that of HR samples at both temperatures, which indicates more membrane leakage in WT cells than the mutants. The difference between PI uptake of WT and mutants increases with TH. Less PI uptake in HR mutants shows that their membrane is less permeable than WT samples. In both WT and HR cells, PI uptake increases with TH. The solid and shaded bars show the linear-scaled and log-scaled versions of the histogram, respectively. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

7. Figure 6
Comparison between ramp and pulse shock treatments. Shown here are bar plots of the pulse-to-ramp ratio values, φ≜ΔYPulse/ΔYRamp and η≜ρRamp/ρPulse, which are, respectively, calculated using (a) conductance data and (b) colony counting results for WT and HR mutants, treated at TH = 48°C and 53°C. (Inset) Shown here is the viability (ρ) for cells subjected to pulse shock at TH = 53°C. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

8. Figure 7
Moderately high temperature stresses can cause large loss of viability without cell lysis. The GFP-expressing strain TL3444 was subjected to 55° pulse treatment for 5.0 min. (a) Untreated and heat-treated cells were examined using inverted fluorescence microscopy. (b) Viability of untreated cells and cells exposed to the heat treatment were determined as colony forming units on LB plates. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

9. Figure 8
(a) Effective activation energy, EA, changes with heating profile (ramp versus pulse). These values are extracted from colony counting data (analytically: Ramp, Anlyt. and Pulse Anlyt. and numerically: Ramp, Num.). EAHR > EAWT, which shows the heat-resistant mutants have more stable membrane structure than the wild-type. The error bars reflect the uncertainty in fitting/extraction of the kinetic parameters. (b) Shown here is 〈ΔY〉t∗ versus TH for WT and mutants exposed to ramp shock for tH = 12 min. The solid lines plot the analytical values, by using the rate constants (kjWT and kfHR) obtained from colony counting data, with kf0WT=1.36×1029 [s−1], and kf0HR=1.3×1042 [s−1]. We used ΔY∞=Average(ΔY70°CWT,ΔY70°CHR). To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions