Plant Proteomics in the Post-genomic Era

Proteomics is one of the most active research fields in the post-genomic era. Here we briefly introduce the scientific background of the origination of proteomics and its content, research method. The new developments of proteomics at the levels of individual plants, tissues, organs and organells, as well as its applications in the area of plant genetic diversity, mutant characterization, and plant physiology, etc are reviewed. At last, the challenge and prospect of proteomics are discussed.

Analysis of Single Nucleotide Polymorphism in Human Paraoxonase 1 Gene(Q192R) with Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry

Introduction Single nucleotide polymorphisms （SNPs） are the most abundant DNA markers in the human genome occurring at a frequency of one in every 500--1000 nucleotides. A variety of methods have been used for the analysis of single nucleotide polymorphisms, including restriction fragment length polymorphism （RFLP）, direct sequencing by using laser-induced fluorescence detectionTM, fluorescence energy transfer, MALDI-TOF MS combined with primer extension or invasive cleavage, and fluorescence polarization. During the past two decades, mass spectrometry has become a very popular tool in the analysis of biomolecules and is perfectly suited to the analysis of single nucleotide polymorphisms （SNPs） due to its speed, low cost, and accuracy. In this work, we used MALDI TOF mass spectrometry to detect the fragments of restriction endonuclease hydrolysis of PCR products flanking a SNP located at paraoxonase 1（Q192R）. Compared with electrophoresis, this method requires less time of analysis and possess a higher accuracy.

Insights into glycan biosynthesis in chemically-induced hepatocellular carcinoma in rats: A glycomic analysis

AIM： To evaluate the qualitative and quantitativechanges in N-linked glycosylation, which occurredin association with diethyl nitrosamine-inducedhepatocellular carcinoma （HCC） in rodents.METHODS： Liver tissues of （1） normal （non-tumorbearing）rats; and （2） tumor-bearing rats; were collectedand were used for histological and GlycanMap？ analyses.Briefly, GlycanMap？ analysis is a high-throughputassay that provides a structural and quantitativereadout of protein-associated glycans using a unique,automated 96-well assay technology coupled tomatrix-assisted laser desorption/ionization time-offlightmass spectrometry and custom bioinformatics.Histopathological studies were carried out to ensure thedevelopment of HCC in the tested animals.RESULTS： The N-glycomic analysis revealed 5glycans; Glc1Man9GlcNAc2, Gal2Man3GlcNac4Fuc1Neu1,Man4G l c N a c 2, G a l 2Man3G l c N a c 4Neu3OAc 3, andMan3GlcNac5Fuc1, which showed significant changesin rat HCC tissues when compared with normal livertissues. Four glycans were increased （P 〈 0.05） andGlc1Man9GlcNAc2 was decreased （5.89 ± 0.45 vs 3.54± 0.21, P 〈 0.01） in HCC tissues compared to normal liver tissues. An increase （66.5 ± 1.05 vs 62.7 ± 1.1,P 〈 0.05） in high-mannose structures in HCC rats wasobserved compared to normal rats. Importantly, HCCrats showed an increase （P 〈 0.05） in both tumorassociatedcarbohydrates and in branched glycans. Thechanges in glycans correlated well with glycan flowchanges reported in the glycan biosynthetic pathway,which indicates the importance of enzyme activitiesinvolved in glycan synthesis at different subcellularlocalizations.CONCLUSION： The reported HCC-associated changesin glycan flow and subcellular localization explain theincrease in high mannose glycans and siayl Lewisglycans common in HCC liver tissues.

Changes of sphingolipids profiles after ischemia-reperfusion injury in the rat liver

Background Hepatic ischemia-reperfusion （I/R） injury occurs in many clinical procedures. The molecular mechanisms responsible for hepatic I/R injury however remain unknown. Sphingolipids, in particular ceramide, play a role in stress and death receptor-induced hepatocellular death, contributing to the progression of several liver diseases including liver I/R injury. In order to further define the role of sphingolipids in hepatic I/R, systemic analysis of sphingolipids after reperfusion is necessary. Methods We investigated the lipidomic changes of sphingolipids in a rat model of warm hepatic I/R injury, by delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometry （DE MALDI-TOF-MS）. Results The total amounts of ceramide and sphingomyelin and the intensity of most kinds of sphingolipids, mainly sphingomyelin, significantly increased at 1 hour after reperfusion （P 〈0.05） and reached peaks at 6 hours after reperfusion （P 〈0.01） compared to controls. Six new forms of ceramide and sphingomyelins appeared 6 hours after reperfusion, they were （m/z） 537.8, 555.7, 567.7, 583.8, 683.5 and 731.4 respectively. A ceramide-monohexoside （m/z） 804.4 （CMH（d18：1C22：1＋Na）＋） also increased after reperfusion and correlated with extent of liver injury after reperfursion. Conclusions Three main forms of sphingolipids, ceramide, sphingomyelin and ceramide-monohexoside, are related to hepatic I/R injury and provide a new perspective in understanding the mechanisms responsible for hepatic I/R injury.