Opus 6

Cultures were stopped after 32 h and harvested by centrifugation (7000 rpm, 10 min). The Pellets were washed twice with saline solution (0.7% NaCl) and re-suspended in 1 mL of the saline solution. Five microlitres of the concentrated yeast were deposited on a selenium multi-plate (96 wells) in 3 replicates and dried in a desiccator under1.5 bar. FTIR measurements were performed in transmission mode using HTS-XT Tensor 27 spectrophotometer (Bruker, Marne la vallée, France). Each experiment was replicated from 3 independent cultures, in order to optimize and control reproducibility [54 ].
The spectra were registered using 64 scans, at a resolution of 4 cm^-1 baseline corrected and normalized using OPUS 6.5 (Bruker) software as previously described in [55 (link)]. An average spectrum was then calculated for each independent culture. If some spectra did not pass the ‘‘quality test” and spectrum reproducibility, 3 more independent cultures were performed to obtain 3 spectra per strain. Spectra analysis would be performed using OPUS 6.5 software (Bruker) by hierarchical cluster analysis (HCA) peaks measurements and integration. To verify the similitude between spectrums recorded from the same culture, calculation of the similitude percentage was performed in the whole spectra using search standard program: similitudes have to be more than 99% [54 ]

Spectral analysis was carried out using OPUS 6.5 Bruker Optics software. As a proxy to membrane fluidity, we analyzed the CH₂ symmetric stretching, ν_s(CH₂), band at ∼2850 cm⁻¹. The band position was obtained by the “peak picking” routine in OPUS 6.5 software (BrukerOptics), using the “standard mode” evaluation (x-coordinate of the relative maximum). By plotting the ν_s(CH₂)-peak position as a function of temperature, we obtained melting curves for the different samples and determined the temperature of the main phase transition of the membrane, T_m, from the maximum of the first derivative of the melting curves. The temperature dependences of the ν_s(CH₂)-band position were used to evaluate the parameter $\beta =\left(\partial {\nu }_{\text{s}}/\partial T\right)/{\nu }_{\text{s}}$ , which shows a very similar temperature behavior to that of the thermal expansion coefficient, $\alpha =\left(\partial V/\partial T\right)/V$ (37 (link)), and can therefore be used as a proxy to membrane thermal expansivity. Membrane-solubilized W(CO)₆ was used to investigate the acyl chain organization and available free volume inside the bilayer. We measured the integrated area of the C≡O antisymmetric stretching, ν_as(CO), of W(CO)₆ in the range between 1960 and 1990 cm⁻¹. Spectra were normalized to the intensity of the ν_s(CH₂) peak at 25°C to allow for a reliable comparison between different samples.

Fourier transform infrared spectroscopy (FTIR, Vertex 70, Bruker Optics, Ettinger, Germany) was used to evaluate the degree of conversion in the experimental resin composites. The unpolymerized dental resins (n = 3) were placed on an attenuated total reflectance (ATR) device inside a polyvinylsiloxane matrix measuring 1 mm in thickness and 4 mm in diameter [32 (link)]. The specimens were covered with polyester matrix strips to obtain the FTIR spectra of unreacted specimens. The specimens were then photoactivated using a light-curing unit for 40 s, and other spectra were obtained. The spectra were obtained with a 4 cm⁻¹ resolution in the spectral range between 400 and 4000 cm⁻¹ with a mirror speed of 2.8 mm/s using Opus software (Opus 6.5, Bruker Optics, Ettlingen, Germany). The DC was calculated considering the intensity of the carbon–carbon double bond (peak at 1640 cm⁻¹) and using the aromatic carbon–carbon double bond (peak at 1610 cm⁻¹) as an internal standard [33 (link)].