Postmortem Interval Estimation Using Protein Chip Technology Combined with Multivariate Analysis Methods / 法医学杂志

OBJECTIVES@#To estimate postmortem interval (PMI) by analyzing the protein changes in skeletal muscle tissues with the protein chip technology combined with multivariate analysis methods.@*METHODS@#Rats were sacrificed for cervical dislocation and placed at 16 ℃. Water-soluble proteins in skeletal muscles were extracted at 10 time points (0 d, 1 d, 2 d, 3 d, 4 d, 5 d, 6 d, 7 d, 8 d and 9 d) after death. Protein expression profile data with relative molecular mass of 14 000-230 000 were obtained. Principal component analysis (PCA) and orthogonal partial least squares (OPLS) were used for data analysis. Fisher discriminant model and back propagation (BP) neural network model were constructed to classify and preliminarily estimate the PMI. In addition, the protein expression profiles data of human skeletal muscles at different time points after death were collected, and the relationship between them and PMI was analyzed by heat map and cluster analysis.@*RESULTS@#The protein peak of rat skeletal muscle changed with PMI. The result of PCA combined with OPLS discriminant analysis showed statistical significance in groups with different time points (P<0.05) except 6 d, 7 d and 8 d after death. By Fisher discriminant analysis, the accuracy of internal cross-validation was 71.4% and the accuracy of external validation was 66.7%. The BP neural network model classification and preliminary estimation results showed the accuracy of internal cross-validation was 98.2%, and the accuracy of external validation was 95.8%. There was a significant difference in protein expression between 4 d and 25 h after death by the cluster analysis of the human skeletal muscle samples.@*CONCLUSIONS@#The protein chip technology can quickly, accurately and repeatedly obtain water-soluble protein expression profiles in rats' and human skeletal muscles with the relative molecular mass of 14 000-230 000 at different time points postmortem. The establishment of multiple PMI estimation models based on multivariate analysis can provide a new idea and method for PMI estimation.

Tissue and Induction Expression Profiles of Rice Phospholipid Hydroperoxide Glutathione Peroxidase at Protein Level / 生物化学与生物物理进展

Proteins arc the major molecules performing life activities, and their spatial and temporal expression profiles in organisms are very important for understanding their accurate functions. Phospholipid hydroperoxide glutathione pcroxidase (PHGPx) is a unique antioxidant enzyme that directly reduces lipid hydroperoxides in biomembranes and plays a vital role in defense against mernhrane peroxidation damage. The protein expression profiles of rice PHGPx (OsPHGPx) were investigated in different rice tissues and under various stress treatments by using Western blot analysis. The results showed that in mature rice plants, OsPHGPx was mainly distributed in leaves, especially flag leaves, and in rice seedlings, OsPHGPx was detected in shoots and leaves. Moreover, OsPHGPx expression in rice seedlings could be markedly induced by H2O2 and NaCI, but weakly influenced by several plant hormones. Time- and dose-dependent effects were observed in both H2O2 and NaCI treatments, and the strongest induction was observed when rice seedlings were treated with 0.5 mmol/L H2O2 for 12 h or 500 mmol/L NaCI for 24 h. Additionally, dimethylthiourea, a H2O2 trap, inhibited H2O2-enhanced expression of OsPHGPx, but did not impair the enhanced effect of NaCI, implying that NaCl-induced OsPHGPx expression was not mediated by H2O2. These results will contribute greatly to further study the exact physiological function of OsPHGPx in rice.

Study on Different Proteomics of Denuded tongue coating / 国际中医中药杂志

Objective To investigate the microbiostatic mechanism of denuded tongue coating, Proteomic methods were used to find differential expression proteins in denuded tongue. Methods The total protein of normal or denuded tongue coating was separated by means of immobilized pH gradient-based two-dimensional gel electrophoresis (2-DE). The differential expression protein was analyzed by using ImageMaster 2D analysis software. Image analysis software was used for comparative analysis to find differential expression proteins; Mass spectrometry (mass spectrometry) was applied to get the corresponding peptide fingerprint (peptide mass finger print_ PMF). Search the database to identify differences in protein.Results Establish two-dimensional gel electrophoresis for normal and denuded tongue; Segregation analysis on four groups of proteome of tongue coating showed that gel could be detected in the protein spots at 1082=t=105 and 1143±140 respectively; Compared with normal group, there are eight points of protein expression being regulated upward and seven points down.Altogether 9 differences in protein expression were identified. Conclusion The sound resolution and repeatability Two-dimensional electrophoresis silver staining pattern were established; Some differences in protein expression related to denuded tongue were identified.