## 3 Results and Discussion
### Analysis of Infrared Spectra from Control and Exposed Cells
For the HWR region, the peaks at 2889 and 2852 cm\({}^{-1}\), related to membrane lipids and proteins (assigned to CH\({}_{3}\) and CH\({}_{2}\) symmetric stretching) show a shift beyond spectral resolution, at 0.5 and 2 Gy doses and a shift toward higher wavenumber at 2 and 4 Gy, respectively. It is worthwhile to note that changes in lipid-related peaks are usually associated with membrane fluidity variations [45]. Shifts toward higher wavenumber are also present for the bands at 3173 cm\({}^{-1}\), for all the irradiated sample, and for the bands at 3071 for the 0.5 and 2 Gy dose. In the fingerprint region, significant shifts are observed for 1291 cm\({}^{-1}\) peak related to Amide III contribution for samples exposed to 0.5 Gy dose and for 1143, 1124, 1058, and 958 cm\({}^{-1}\) features when samples exposed to the different doses are considered. The latter wavenumber shifts point to changes in DNA conformation [40, 46]. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Peak** & **Assignment** & \\ \hline
**cm\({}^{-1}\)** & **DNA/RNA** & **Protein** & **Lipid** & **Carbohydrate** \\ \hline
3500–3300 & & & O-H v \\ \hline
3291 & Amide A (-N-H v) & O-H v \\ \hline \hline \end{tabular}
\end{table} 
Table 2: FT-IR peaks observed in the spectrum of control cells, with assignments in agreement with the data reported in the literature [1, 3, 4, 14, 35, 47]; abbreviation: as = asymmetric, s = symmetric, v = stretching, \(\delta\) = bending, sc = scissoring, vbr = vibration, a. a. = free amino acids. The indicated position of every peak is the centre of the relative Gauss-cross-Lorentzian function obtained from the deconvolution fit. The peaks indicated in bold character are obtained by the analysis of second derivatives. Figure 2: Deconvolution of average control spectra (**A**) in the high wavenumber region (3600–2600 cm\({}^{-1}\)), (**B**) in the fingerprint region (1800–900 cm\({}^{-1}\)), (**C**) in the Amide I band region (1740–1580 cm\({}^{-1}\)) and (**D**) in the Amide III band region (1350–1180 cm\({}^{-1}\)). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Peak** & \multicolumn{2}{c}{**Assignment**} \\ \hline
**cm\({}^{-1}\)** & **DNA/RNA** & **Protein** & **Lipid** & **C carbohydrate** \\ \hline
3173 & -NH\({}_{3}\)\({}^{+}\) as. v (a. a.) & & \\ \hline
3071 & Amide B(-N-H v, \(\delta\)) & & O-H v \\ \hline
2959 & CH\({}_{3}\) as. N & CH\({}_{3}\) as. v & \\ \hline
2924 & & CH\({}_{2}\) as. v & \\ \hline
2889 & CH\({}_{3}\) s. v & CH\({}_{3}\) s. v & \\ \hline
2852 & & CH\({}_{2}\) s. v & \\ \hline
1643 & Amide I (C=O v, C-N v) & & \\ \hline
1534 & Amide II (C-Nv,C-NH \(\delta\)) & & \\ \hline
1448 & CH\({}_{3}\) as. \(\delta\), CH\({}_{2}\) sc. & CH\({}_{3}\) as. \(\delta\), CH\({}_{2}\) sc. & \\ \hline
1394 & COO\({}^{-}\) s. v & & \\ \hline
1304 & Amide III(-N-H\({}_{3}\),-C-N v) & & \\ \hline
**1291** & Amide III(-N-H\({}_{3}\),-C-N v) & & \\ \hline
1227 & PO\({}_{2}\)\({}^{-}\) as. v & C-O-P v & \\ \hline
**1207** & C-H ring \(\delta\) & & \\ \hline
**1171** & Sugar -phosphate backbone vbr & & \\ \hline
1166 & & CO-O-C s. as. v & \\ \hline
**1143** & Ribose C-O v & & \\ \hline
1124 & v -C-O & & \\ \hline
**1100** & P-O-C s. v & & \\ \hline
1086 & PO\({}_{2}\)\({}^{-}\) s. v & C-O-P v & \\ \hline
1058 & v -C-O & & \\ \hline
965 & PO\({}_{4}\)\({}^{-}\) s. v & C-O v, C=C v (a. a.) & \\ \hline \end{tabular}
\end{table} 
Table 2: _Cont._