Each calorimeter had an outer thermostatic loop provided by a Julabo F32-HE device operating in standard mode. 3D sensor protection was provided by a Nitrogen gas purge (99.99% SIAD – TP). The Calisto v1.077 software
package was used for data acquisition and primary signal processing. This included baseline integration end export in Excel with equally spaced time increments. Heat values obtained were further analyzed in Excel and Origin 8.1. Exported baselines were further processed in Peakfit. FG-4592 cell line Peakfit processing of the thermograms Data exported from Calisto were processed in Peakfit by means of previously reported routines [16, 17]. Whenever PPAR agonist inhibitor necessary, Savitsky-Golay smoothing was performed, generally with the “Al Expert” option. Calisto-generated baselines were imported and subtracted from the heat flow (HF, mW) signal. The time zero was changed for each thermogram by means of “Enter Calculation” option in Peakfit, allowing to a left shift of the whole data corresponding to the left intersection of the baseline
and HF. This procedure brings all thermograms to a common X (time) scale, but definitely excludes any analysis of the growth lag time. The resulted data were subjected to “Area normalize” resulting in the “normalized heat flow” (NHF, h-1) [16, 17]. This brings all thermograms to a common Y (NHF) scale, with the advantage that areas of the component peaks represent their fraction to the overall thermal effect. All subsequent peak fitting involved the NHF – time thermograms. Several selleck screening library built-in asymmetric peak functions were tried (EMG, GMG, LogN, Giddings, Pearson IV, HVL, etc.). The best one for the analyzed data proved to be the Haarhof – Van der Linde (HVL) chromatography function. This function resulted in both the best statistical criteria (r2, F-statistic, standard errors,
etc.) and most reliable variations of the fitting parameters among the member of each set. As detailed in section C1, peak parameters were allowed to vary independently learn more through the “Vary Widths” and “Vary Shape” options. The “Medium (Lorentz Err.) Robust Minimization” procedure was applied instead of the classical least-squares one. Bacterial strains The reference strains of Staphylococcus aureus – ATCC 25923 and Escherichia coli – ATCC 25922 were used throughout the present study. Culture media Bacterial culture media were prepared from stock Tryptic Soy Broth (TSB, Oxoid, UK), which is a mixture of Pancreatic digest of casein (17 g), NaCl (5 g), Papaic digest of soybean meal (3 g), K2HPO4 (2.5 g), Glucose (2.5 g) to 1 Liter and a pH of 7.3 ± 0.2 at 25°C. The medium was autoclaved before use and was microbiologically pure. For viability counts, preparation of isolated colonies for inoculation and random sample check of aseptic technique, we used plates with Tryptic Soy Agar (TSA, Oxoid, UK); this solid medium has the same basic composition as TSB.