17 research outputs found
Oxidative protein labeling in mass-spectrometry-based proteomics
Oxidation of proteins and peptides is a common phenomenon, and can be employed as a labeling technique for mass-spectrometry-based proteomics. Nonspecific oxidative labeling methods can modify almost any amino acid residue in a protein or only surface-exposed regions. Specific agents may label reactive functional groups in amino acids, primarily cysteine, methionine, tyrosine, and tryptophan. Nonspecific radical intermediates (reactive oxygen, nitrogen, or halogen species) can be produced by chemical, photochemical, electrochemical, or enzymatic methods. More targeted oxidation can be achieved by chemical reagents but also by direct electrochemical oxidation, which opens the way to instrumental labeling methods. Oxidative labeling of amino acids in the context of liquid chromatography(LC)âmass spectrometry (MS) based proteomics allows for differential LC separation, improved MS ionization, and label-specific fragmentation and detection. Oxidation of proteins can create new reactive groups which are useful for secondary, more conventional derivatization reactions with, e.g., fluorescent labels. This review summarizes reactions of oxidizing agents with peptides and proteins, the corresponding methodologies and instrumentation, and the major, innovative applications of oxidative protein labeling described in selected literature from the last decade
Using a gamified mobile app to increase student engagement, retention and academic achievement
Abstract This study investigated whether the use of a gamified mobile learning app influenced studentsâ academic performance and boosted their engagement in the subject. Created to better engage students in lecture content, the app was used to deliver multiple-choice content-based quizzes directly to studentsâ personal mobile devices post-lecture and pre-tutorial. After measuring the relationships between studentsâ app usage and their engagement, retention and academic achievement in the subject, it is suggested that following the appâs introduction, student retention rates and academic performance increased, and there was a positive correlation between studentsâ scoring highly on the app and achieving higher academic grades. While the appâs affordances for learning are promising, the causal relationship between the app usage and improved student outcomes requires further investigation. Conclusions made in the context of the wider scholarship of mobile app enhanced learning and applied game principles in HE
The characteristics of the synonymous codon usage in hepatitis B virus and the effects of host on the virus in codon usage pattern
<p>Abstract</p> <p>Background</p> <p>Hepatitis B virus (HBV) infection is one of the main human health problem and causes a large-scale of patients chronic infection worldwide.. As the replication of HBV depends on its host cell system, codon usage pattern for the viral gene might be susceptible to two main selections, namely mutation pressure and translation selection. In this case, a deeper investigation between HBV evolution and host adaptive response might assist control this disease.</p> <p>Result</p> <p>Relative synonymous codon usage (RSCU) values for the whole HBV coding sequence were studied by Principal component analysis (PCA). The characteristics of the synonymous codon usage patterns, nucleotide contents and the comparison between ENC values of the whole HBV coding sequence indicated that the interaction between virus mutation pressure and host translation selection exists in the processes of HBV evolution. The synonymous codon usage pattern of HBV is a mixture of coincidence and antagonism to that of host cell. But the difference of genetic characteristic of HBV failed to be observed to its different epidemic areas or subtypes, suggesting that geographic factor is limited to influence the evolution of this virus, while genetic characteristic based on HBV genotypes could be divided into three groups, namely (i) genotyps A and E, (ii) genotype B, (iii) genotypes C, D and G.</p> <p>Conclusion</p> <p>Codon usage patterns from PCA for identification of evolutionary trends in HBV provide an alternative approach to understand the evolution of HBV. Further more, a combined selection of mutation pressure with translation selection on codon usage might shed a light on understanding the evolutionary trends of HBV genotypes.</p