Strategies and Perspectives for UV Resonance Raman Applicability in Clinical Analyses of Human Sperm RNA

Developing a deeper knowledge about the impact of DNA and RNA epigenetic mutations on sperm production and fertilization performance is essential for selecting best quality samples in Assisted Reproductive Technologies (ART). Indeed, sperm RNAs adenine and guanine are likely to be methylated in low quality RNA sperm samples and their study requires the employment of techniques able to isolate high quality nucleic acids. UV resonance Raman spectroscopy represents a valuable tool that is able to monitor peculiar molecular modifications occurring predominantly in nucleic acids, being less sensitive to the presence of other biological compounds. In this work, we used an UV Resonance Raman (UVRR) setup coupled to a synchrotron radiation source tuned at 250 nm, in order to enhance sperm RNAs adenine and guanine vibrational signals, reducing also the impact of a fluorescence background typically occurring at lower energies. Despite that our protocol should be further optimized and further analyses are requested, our results support the concept that UVRR can be applied for setting inexpensive tools to be employed for semen quality assessment in ART.

An insight into thermal stability of DNA in hydrated ionic liquids from multi-wavelengths UV Resonance Raman experiments

The utility of Ionic liquids (ILs) as alternative solvents for stabilizing and preserving for a long time the native structure of DNA may be envisaged for biotechnological and biomedical applications...

Use of UV resonance Raman spectroscopy for assessing the brightness stability of ozone TCF bleached pulp

This study intends to explain the difference in brightness stability between hardwood ECF and TCFz kraft pulps bleached by DEpDD and A(ZEo)(ZEo)(ZP) sequences respectively, using UV Resonance Raman (UVRR) spectroscopy. The brightness stability of the pulps was tested via dry aging experiments where the Post-Color Number (PCN) of the ECF pulp was twice that of the TCF pulp. The aged and non-aged bleached pulps were analyzed with UVRR spectroscopy to identify the cause of the large difference in PCN. The spectra of ECF and TCF bleached pulps presented clear differences in the intensities of the Raman shifts associated to lignin, lignin-like compounds, and degradation products such as muconic acids. To identify more specifically the compounds affecting the PCN, several post-bleaching treatments were applied on the ECF pulp including single stages (E, B, P, Z) or combinations (ZE, ZB, ZP), and their UVRR spectra analyzed. It was found that alkaline-soluble compounds were the main culprits for the difference in PCN values between ECF and TCFz pulps. ZP combination was the most efficient in eliminating residual lignin and other unsaturated components and for the development of brightness and brightness stability.

Vibrational Relaxation of Functional Groups in dAMP Molecules Probed with UV Resonance Raman Spectroscopy

Dynamical properties of functional groups in 2�-deoxyadenosine-5�-monophosphate (dAMP) compound, were identified by UV resonance Raman spectroscopy (UVRR), upon varying nucleotide concentration in aqueous solution (200-600 μM). The studied full-widths at half-maximum (fwhm�s) were found between 13 - 21 cm-1 and the corresponding global relaxation times were faster than 0.817 ps and slower than 0.506 ps. Also, the band around 1430 cm-1 (C4N9-δC8H) in the UV resonance Raman spectrum of dAMP molecule at 400 μM concentration in aqueous solution, was selected for vibrational band shape analysis through time correlation function (CF) concept. Current theories developed for vibrational dephasing (Kubo-Rothschild and Oxtoby) have been applied to this profile and relevant relaxation parameters have been obtained and discussed. The best fit parameters for this dissipation channel of the vibrational excitation energy were established. To our knowledge this is the first UVRR study on nucleotide vibrational band shape analysis through time correlation function concept.