Identification and relative quantification of tyrosine nitration in a model peptide using two-dimensional infrared spectroscopy

Nitration of tyrosine in proteins and peptides is a post-translational modification that occurs under conditions of oxidative stress. It is implicated in a variety of medical conditions, including neurodegenerative and cardiovascular diseases. However, monitoring tyrosine nitration and understanding its role in modifying biological function remains a major challenge. In this work, we investigate the use of electron-vibration-vibration (EVV) two-dimensional infrared (2DIR) spectroscopy for the study of tyrosine nitration in model peptides. We demonstrate the ability of EVV 2DIR spectroscopy to differentiate between the neutral and deprotonated states of 3-nitrotyrosine, and we characterize their spectral signatures using information obtained from quantum chemistry calculations and simulated EVV 2DIR spectra. To test the sensitivity of the technique, we use mixed-peptide samples containing various levels of tyrosine nitration, and we use mass spectrometry to independently verify the level of nitration. We conclude that EVV 2DIR spectroscopy is able to provide detailed spectroscopic information on peptide side-chain modifications and to detect nitration levels down to 1%. We further propose that lower nitration levels could be detected by introducing a resonant Raman probe step to increase the detection sensitivity of EVV 2DIR spectroscopy. (Graph Presented)

Dynamics of aggregated states resolved by gated fluorescence in films of room temperature phosphorescent emitters

Phenazine derivative molecules were studied using steady state and time resolved fluorescence techniques and demonstrated to lead to strong formation of aggregated species, identified as dimers by time dependent density functional theory calculations. Blended films in a matrix of Zeonex®, produced at different concentrations, showed different contributions of dimer and monomer emissions in a prompt time frame, e.g. less than 50 ns. In contrast, the phosphorescence (e.g. emission from the triplet state) shows no significant effect on dimer formation, although strong dependence of the phosphorescence intensity on concentration is observed, leading to phosphorescence being quenched at higher concentration

Dental Caries and Periodontal Disease in Brazilian Children and Adolescents with Cerebral Palsy

The aim of the present study was determine the prevalence and factors associated with dental caries and periodontal disease in Brazilian children and adolescents with cerebral palsy (CP). This is a cross-sectional study conducted with 80 patients ranging in age from 2 to 18 years old. Oral exams were conducted by an examiner with records of DMFT, dmft, Gingival Bleeding Index (GBI) and Community Periodontal Index (CPI). The statistical analysis used Poisson Regression with robust variance estimation (α = 0.05). The prevalence of dental caries was 59.3%, with DMFT and mean dmft of 1.71 ± 2.42 and 2.22 ± 3.23, respectively. The mean GBI was 22.44%, and in the CPI, the prevalence of gingival bleeding, calculus, shallow and deep pockets were 94.73%, 79.62%, 12.90% and 3.22%, respectively. The caregiver’s educational level of less than eight years were associated with the dental caries experience (PR = 1.439; 95%CI = 1.09–1.89). The periodontal alterations were associated with female sex (PR = 0.82; 95%CI = 0.69–0.97), caregiver’s educational level of less than eight years (PR = 1.15; 95%CI = 1.03–1.29), poor oral perception (PR = 0.89; 95%CI = 0.80–0.98), serious communication problem (PR = 0.87; 95%CI = 0.76–0.99) and athetoid type of CP (PR = 0.85; 95%CI = 0.75–0.97). The patients with CP presented high dental caries experience and periodontal alterations, which were associated with their demographic, socioeconomic, oral health perception and systemic information