Spectroscopy - Volume 23, issue 2

Authors: Muntean, Cristina M. | Halmagyi, Adela | Puia, Mircea D. | Pavel, Ioana

Article Type: Research Article

Abstract: The vibrational spectra of eight genomic DNAs from leaf tissues (sword fern (Nephrolepis exaltata L.), chrysanthemum (Dendranthema grandiflora Ramat.), redwood (Sequoia sempervirens D. Don. Endl.), orchids (Cymbidium × hybrida), common sundew (Drosera rotundifolia L.), potato (Solanum tuberosum L.) and scopolia (Scopolia carniolica Jacq.)) have been analyzed using FT-Raman spectroscopy, in the wavenumber range 500–1800 cm−1 . FT-Raman signatures, spectroscopic assignments and structural interpretations for these plant genomic DNAs are reported. Spectral differences among two genomic DNAs, independently extracted from chrysanthemum leaves, are to be observed between 1000–1200 cm−1 . Besides, similarities in the FT-Raman spectra of genomic DNAs from …potato and scopolia leaves, respectively, have been found. This might be explained by their belonging to the same family (Solanaceae). Other spectral differences among genomic plant DNAs have also been observed. These findings demonstrate that Raman spectroscopy may be exploited to distinguish different plant genomic DNAs. The present study provides a basis for future use of Raman spectroscopy to analyze specific plant DNA–ligand interactions or DNA structural changes induced by plants' stress conditions associated with their natural environment. Show more

Keywords: Molecular structure, genomic DNA, leaf tissue, FT-Raman spectroscopy

DOI: 10.3233/SPE-2009-0375

Citation: Spectroscopy, vol. 23, no. 2, pp. 59-70, 2009

Authors: Lázaro, João Carlos | Pacheco, Marcos Tadeu T. | Rodrigues, Kátia Calligaris | de Lima, Carlos José | Moreira, Leonardo Marmo | Villaverde, Antonio Balbin | Silveira Jr., Landulfo

Article Type: Research Article

Abstract: The present work is focused on the influence of the slit aperture and time exposure of the infrared light on the Charge Coupled Device (CCD) in relation to their physical effects, in order to improve the Raman spectrum characteristics. Indeed, the alterations in slit aperture and CCD time exposure affect significantly important spectral properties, such as the spectral intensity, Signal to Noise Ratio (SNR) and band width resolution of the Raman spectra. Therefore, the present proposal has the aim of to found the optimum conditions of instrumental arrangement, involving the minimum collection time and maximum signal quality in dispersive Raman …spectrometers. Samples of dehydrated human teeth and naphthalene were evaluated with a Raman dispersive spectrometer employing excitation wavelength of 830 nm in several integration times and spectrometer slit apertures. The analysis of the spectral intensity, SNR and band width of selected Raman peaks allowed to infer that these properties of a dispersive Raman spectrum depend directly of the exposure time on the detector as well as spectrograph slit aperture. It is important to register that the higher SNR was obtained with higher exposure time intervals. To the samples evaluated in the present article, the band width has lower values for slit apertures of 100–150 μm, i.e., in this aperture range the spectral resolution is maximum. On the other hand, the intensity and SNR of the Raman spectra becomes optimal for slit apertures of 150–200 μm, since this aperture does not affect significantly the integrity of the Raman signal. In this way, we can to propose that in approximately 150 μm, it is possible to obtain an optimum condition, involving spectral resolution as well as SNR and spectral intensity. In any case, depending of the priorities of each spectral measurement, the instrumental conditions can be altered according with the necessities of each specific chemical analysis involving a determined sample. The present data are discussed in details in agreement with recent data from literature. Show more

Keywords: Raman spectroscopy, spectral resolution, band width resolution, signal to noise ratio (SNR)

DOI: 10.3233/SPE-2009-0377

Citation: Spectroscopy, vol. 23, no. 2, pp. 71-80, 2009

Authors: Tajmir-Riahi, H.A. | N'soukpoé-Kossi, C.N. | Joly, D.

Article Type: Review Article

Abstract: In this chapter the fundamental question of how does protein–DNA or protein–RNA interaction affect the structures and dynamics of DNA, RNA and protein is addressed. Models for calf-thymus DNA and transfer RNA interactions with human serum albumin (HSA), ribonuclease A (RNase A) and deoxyribonuclease I (DNase I) are presented here, using Fourier Transform Infrared (FTIR) spectroscopy in conjunction with UV-visible and CD spectroscopic methods. In the models considered, the binding sites, stability and structural aspects of protein–DNA and protein–RNA are discussed and the effects of protein interaction on the secondary structures of DNA, RNA and protein were determined.

Keywords: DNA, protein, binding mode, binding constant, secondary structure, FTIR spectroscopy

DOI: 10.3233/SPE-2009-0371

Citation: Spectroscopy, vol. 23, no. 2, pp. 81-101, 2009

Authors: Chen, Changyun | Chen, Kai | Long, Qi | Ma, Meihua | Ding, Fei

Article Type: Research Article

Abstract: A novel complex Sm(III) complex with ofloxacin was synthesized and characterized on the basis of elemental analyses, molar conductivities, IR spectra, thermal analysis (TG-DSC), 1 H-NMR spectra. Then, spectrometric titration, ethdium bromide displacement experiments by UV spectroscopy, ionic influence, viscosity measurements and Circular Dichroism (CD) spectroscopic measurements were conducted to characterize the interaction between the complex and CT-DNA. Results obtained indicate that the complex bound with CT-DNA via an intercalation mechanism. The binding constants and binding sites number of the Sm(III) complex with CT-DNA were 1.80×105 l·mol−1 and 1, respectively.

Keywords: Sm complex with ofloxacin, structural characterization, DNA-binding properties

DOI: 10.3233/SPE-2009-0378

Citation: Spectroscopy, vol. 23, no. 2, pp. 103-111, 2009

Authors: Khanmohammadi, Mohammadreza | Mobedi, Hamid | Mobedi, Elaheh | Kargosha, Kazem | Bagheri Garmarudi, Amir | Ghasemi, Keyvan

Article Type: Research Article

Abstract: A new method is presented for quantitative determination of naltrexone in aqueous solutions based up on the wavelength selection in mid-FTIR spectra using partial least squares (PLS) technique. The main aim is to find wavelengths which produce significant improvements in PLS prediction. PLS wavelength selection treatment is performed on the data obtained by attenuated total reflectance Fourier transform infrared spectrometry in 830–1800 cm−1 wavenumber range. No separation or extraction steps are required prior to determination procedure and a simple pretreatment is performed. Absorbance spectra were employed for measurements using a set of 7 aqueous standard solutions of naltrexone. The …method is applicable for pharmaceutical samples in aqueous solution in the presence of impurities, while it is simple, rapid and accurate. The results obtained from real samples were compared with those obtained using Ultra Violet spectrophotometry as a reference method. Statistical parameters such as R2 , REP, RMSEC and RMSECV were evaluated, and number of factors, number of scans and resolution were also optimized. In this method R2 and RMSEC for proposed procedure have been found to be 0.9983 and 0.1297, respectively. Show more

Keywords: ATR-FTIR, wavelength selection, PLS, naltrexone, determination, spectrometry

DOI: 10.3233/SPE-2009-0376

Citation: Spectroscopy, vol. 23, no. 2, pp. 113-121, 2009