Two-dimensional gel electrophoresis and surface-enhanced laser desorption ionization-time of flight-mass spectrometry for detection of protein expression profiles in the hippocampus following closed brain injury

Gene expression profile changes in brain regions following traumatic brain injury at the gene level cannot sufficiently elucidate gene expression time, expression amount, protein post-translational processing or modification. Therefore, it is necessary to quantitatively analyze the gene expression profile using proteomic techniques. In the present study, we established a rat model of closed brain injury using Marmarou＇s weight-drop device, and investigated hippocampal differential protein expression using two-dimensional gel electrophoresis and surface-enhanced laser desorption ionization-time of flight-mass spectrometry. A total of 364 protein peaks were detected on weak cation exchange-2 protein chips, including 37 differential protein peaks. 345 protein peaks were detected on immobilized metal affinity capture arrays-Cu, including 12 differential protein peaks Further examination of these differential proteins revealed that glucose-regulated protein and proteasome subunit alpha type 3 expression were significantly upregulated post-injury. These results indicate that brain injury can alter protein expression in the hippocampus, and that glucose-regulated protein and proteasome subunit alpha type 3 are closely associated with the occurrence and development of traumatic brain injury.

Protein expression of sensory and motor nerves Two-dimensional gel electrophoresis and mass spectrometry

The present study utilized samples from bilateral motor branches of the femoral nerve, as well as saphenous nerves, ventral roots, and dorsal roots of the spinal cord, to detect differential protein expression using two-dimensional gel electrophoresis and nano ultra-high performance liquid chromatography electrospray ionization mass spectrometry tandem mass spectrometry techniques. A mass spectrum was identified using the Mascot search. Results revealed differential expression of 11 proteins, including transgelin, Ig kappa chain precursor, plasma glutathione peroxidase precursor, an unnamed protein product （gil55628）, gfyceraldehyde-3-phosphate dehydrogenase-like protein, lactoylgfutathione lyase, adenyfate kinase isozyme 1, two unnamed proteins products （gil55628 and gi11334163）, and poly（rC）-binding protein 1 in motor and sensory nerves. Results suggested that these proteins played roles in specific nerve regeneration following peripheral nerve injury and served as specific markers for motor and sensory nerves.

Cerebrospinal fluid diagnostic markers for two-dimensional electrophoresis-mass spectrometry in Parkinson’s disease patients

BACKGROUND： Previous studies have confirmed the existence of specific proteins in body fluid of Parkinson＇s disease （PD） patients. However, the existing research has contained several interference factors with poor reproducibility and has not focused on patients grouped according to disease duration. OBJECTIVE： To verify differential expression of proteins in cerebrospinal fluid of PD patients grouped in order of disease severity through the use of two-dimensional electrophoresis-mass spectrometry methods. DESIGN, TIME AND SETTING： The proteomic-based, case-control study was performed between September 2008 and June 2009 at the Key Laboratory of Neurology in the First Affiliated Hospital of Chongqing Medical University. PARTICIPANTS： A total of 52 outpatients and/or inpatients, who were admitted to the Department of Neurology in the First Affiliated Hospital of Chongqing Medical University between 2008 and 2009, were randomized into the present study. Among them, 27 PD patients served as the PD group and were assigned to three subgroups according to modified Webster, Hoehn, and Yahr rating scales： 14 = mild, 8 = moderate, and 5 = severe; non-PD group of 16 patients included 5 cases of viral meningitis, 3 cases of acute myelitis, 1 case of Guillain-Barre syndrome, 2 cases of tuberculous meningitis, 2 cases of restless legs syndrome, and 3 cases of essential tremor; control group （n = 9） consisted of muscular tension headache in 6 cases, as well as syncope, trigeminal neuralgia, idiopathic orthostatic hypotension in 1 case. METHODS： Cerebrospinal fluid was collected from the involved patients using the lumbar puncture method. Proteins in the cerebrospinal fluid were separated by two-dimensional electrophoresis. MAIN OUTCOME MEASURES： Characteristics of protein electrophoresis patterns were analyzed, differentially expressed proteins were detected using matrix-assisted laser desorption ionization time of flight mass spectrometry, and protein data were analyzed in the Mascot database. RESULTS： Five protein electropherograms were analyzed by PDQuest 8.0, and （789 ± 32） protein spots were observed. There were significant differences in four protein spots in each of the PD sub-groups compared with the non-disease and control groups. Expression was down-regulated in three protein spots and up-regulated in one protein spot; 100% repetition rate was observed in four protein spots. According to the Mascot database, protein spots with down-regulated expression were as follows： DNA-guided RNA polymerase III subunit RPC5 （score： 50 points）; double serine, threonine, and tyrosine protein kinase （score： 64 points, P 〈 0.05）; activity-regulated cytoskeleton-associated protein （score： 58 points, P 〈 0.05）. However, G2 mitotic-specific cyclin was up-regulated （score： 84 points, P 〈 0.05）. CONCLUSION： Differential protein expression in the cerebrospinal fluid of PD patients was detected by two-dimensional electrophoresis-mass spectrometry, revealing changes in DNA-guided RNA polymerase III subunit RPC5, double serine, threonine, and tyrosine protein kinase, activity-regulated cytoskeleton-associated protein, and G2 mitotic cell cyclin, with good reproducibility.

Specific protein expression in a rat model of early focal cerebral ischemia:Fluorescent two-dimensional difference gel electrophoresis

BACKGROUND： The use of fluorescent two-dimensional difference gel electrophoresis （2D-DIGE） has been shown to compensate for the shortcomings of conventional two-dimensional gel electrophoresis, such as poor repeatability and large systematic errors. However, little information is presently available regarding the use of 2D-DIGE to investigate mechanisms of ischemic cerebrovascular diseases. Plasma and body fluids have been utilized in proteomic technology to study ischemic cerebrovascular diseases. OBJECTIVE： To perform proteomic analysis of fresh rat brain tissue in peripheral ischemic regions using 2D-DIGE 6 hours after middle cerebral artery occlusion （MCAO）, and to identify specific proteins closely associated with early ischemic cerebrovascular diseases. DESIGN, TIME AND SETTING： Proteomics-based, randomized, controlled, animal experiment was performed at the Laboratories of Neurology and Proteomics, Jilin University between January and April 2006. MATERIALS： 2, 3, 5-triphenyl tetrazolium chloride was purchased from Sigma, USA. Ettan DALTSix system, DeCyder DIA V5.0 differential analysis software, and Ettan matrix-assisted laser desorption/ionization time-of-flight mass spectrometer （MALDI-TOF-MS） were purchased from Amersham Bioscience, Sweden. METHODS： Eight healthy, male, Wistar rats were randomized to experimental and control groups, with four rats in each group. In the experimental group, rat models of focal cerebral ischemia were established by MCAO. In the control group, the internal and external carotid arteries were exposed and then immediately sutured, and the remaining procedures were identical to the experimental group. MAIN OUTCOME MEASURES： At 6 hours after cerebral ischemia, protein expression in the peripheral ischemia region of the experimental group was compared with the control group using 2D-DIGE. Protein spots that exhibited statistical differences between experimental and control groups with 〉 1.4 attributable risk were screened using DeCyder DIA V5.0 differential analysis software. Differential proteins were identified using MALDI-TOF-MS. RESULTS： Triphenyl tetrazolium chloride staining results revealed pink, normal brain tissue and white, ischemic brain tissue, suggesting successful MCAO establishment. The average matching rate of four 2D-DIGE gels was 92.4%. There were （1 758 ± 43） protein spots on each gel, with similar distribution modes. At 6 hours after focal cerebral ischemia, 13 protein spots exhibited marked expression changes, including significantly increased （n = 7） and decreased （n = 6） expression （P 〈 0.05）. MALDI-TOF-MS results revealed two differential protein spots： a-tubulin and heat shock protein 27, which were significantly decreased in the experimental group compared with the control group （P 〈 0.05）. CONCLUSION： Thirteen protein spots with expression changes were revealed by 2D-DIGE proteomics technology. Of them, a-tubulin and heat shock protein 27 expressions were markedly decreased during the early stage of cerebral ischemia. These two proteins were presumed to be proteins associated with early ischemic cerebrovascular diseases.

Proteome analysis of round-headed and normal spermatozoa by 2-D fluorescence difference gel electrophoresis and mass spectrometry

Globozoospermia is a severe form of teratozoospermia characterized by round-headed spermatozoa with an absent acrosome, an aberrant nuclear membrane and midpiece defects. Globozoospermia is diagnosed by the presence of 100% round-headed spermatozoa on semen analysis, and patients with this condition are absolutely infertile. The objective of this study was to investigate the differences in protein expression between human round- headed and normal spermatozoa. Two-dimensional （2-D） fluorescence difference gel electrophoresis （DIGE） coupled with mass spectrometry （MS） was used in this study. Over 61 protein spots were analysed in each paired normal/round-headed comparison, using DIGE technology along with an internal standard. In total, 35 protein spots identified by tandem mass spectrometry （MS/MS） exhibited significant changes （paired t-test, P 〈 0.05） in the expression level between normal and round-headed spermatozoa. A total of nine proteins were found to be upregulated and 26 proteins were found to be downregulated in round-headed spermatozoa compared with normal spermatozoa. The differentially expressed proteins that we identified may have important roles in a variety of cellular processes and structures, including spermatogenesis, cell skeleton, metabolism and spermatozoa motility.

Two-dimensional electrophoretogram of acute brain injury-associated proteins Comparison between injured and normal cerebral cortex

BACKGROUND： To this date, specific molecular markers for early diagnosis and prognosis monitoring of craniocerebral injury in clinical medicine do not exist. Therefore, differential detection of specific proteins might play an important role in diagnosis and treatment of this type of brain injury. OBJECTIVE： To compare differential cerebral cortical protein expression of craniocerebral injury patients and normal subjects through the use of proteomics. DESIGN： Contrast observation. SETTING： Department of Neurosurgery, Xiangya Hospital of Central South University. PARTICIPANTS： Ten patients （6 males and 4 females, 20 58 years old）, with severe craniocerebral injury, were selected at the Department of Neurosurgery, Xiangya Hospital of Central South University, from June 2004 to December 2006. All patients were diagnosed with CT test and Glasgow test （scores 〈 8）. Surgery was performed 4-12 hours after craniocerebral injury, and injured cortical tissues of the frontal and temporal lobes were resected for sampling. At the same time, control cortical tissues were collected from frontal and temporal lobes of 2 epileptic patients who underwent hippocampus-nucleus amygdala resection, and 2 lateral ventricular tumor patients who underwent tumor resection. The participants and their relatives provided confirmed consent, and this study received confirrned consent from the local ethics committee. METHODS： Ten samples from injured patients and 4 normal samples were compared through the use of proteomics. Total protein was separated by using two-dimensional electrophoresis with immobilized pH gradients, and the differential protein expressions were compared using image analysis after blue-sliver staining. Differential protein spot expressions were analyzed with a matrix-assisted laser desorption/ionization time of flight mass spectrometry （MALDI/TOF MS） and electrospray ionization-quadrupole time of flight mass spectrometry （ESI-Qq TOF MS）. MAIN OUTCOME MEASURES：① Two-dimensional electrophoresis of protein from cerebral cortex; ② differential protein expression. RESULTS： ① Two-dimensional electrophoresis of protein from cerebral cortex： two-dimensional gel electrophoretogram, which is considered to have high resolution and consistent duplication, was performed on injured cortical tissues and normal cortical tissues. The image analysis system detected 21 differential protein spots. ② Differential protein spot expressions： mass spectrometry resulted in 17 differential protein spots that related to metabolic response, oxidative stress response, and signal transduction. CONCLUSION： MALDI/TOF MS and ESI-Qq TOF MS are exceptional methods for evaluating differential protein expression. Results from this study indicated 17 different craniocerebral injury-associated proteins.

Identification of differentially expressed proteins in human stage Ⅰ lung adenocarcinoma and tumor-adjacent tissues with two-dimension gel electrophoresis profiling

Objective： The aim of this study was to establish reproducible two-dimensional electrophoretic assay used for profiling and identification of differentially expressed proteins in human stage I lung adenocarcinoma and paired normal tumor-adjacent tissue. Methods： The proteins from 12 human stage I lung adenocarcinoma tissues and normal tumor-adjacent tissues were separated using isoelectric focusing electrophoresis （the first dimension） and the subsequent homogeneous SDS-polyacrylamide gel electrophoresis （SDS-PAGE） （the second dimension）. The differentially expressed proteins were determined with PDQuest image analysis software, and identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF-MS） and database searching. Results： The well-reproducible 2-DE gel patterns of human stage I lung adenocarcinoma and normal tumor-adjacent tissues were profiled and 26 differentially expressed proteins uncovered. Nine of these 26 protein spots were cut out from the preparation gels and determined with MALDI-TOF-MS. Searching against the protein database, four candidate proteins were identified. They were 60S acidic ribosomal protein P2, Cathepsin B1, Apolipoprotein A-I precursor, and La 4.1 protein. Conclusion： In this study, high reproducible 2-DE gel protein images of human stage I lung adenocarcinoma and paired normal tumor-adjacent tissues were achieved successfully, and 4 differentially expressed proteins were revealed. These data will be helpful for screen of early biomarker and study of molecular mechanisms of human lung adenocarcinoma.

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.

Comparative proteomics analysis of human gastric cancer

AIM: To isolate and identify differentially expressed proteins between cancer and normal tissues of gastric cancer by two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). METHODS: Soluble fraction proteins of gastric cancer tissues and paired normal tissues were separated by 2-DE. The differentially expressed proteins were selected and identified by MALDI-TOF-MS and database search. RESULTS: 2-DE profiles with high resolution and reproducibility were obtained. Twenty-three protein spots were excised from sliver staining gel and digested in gel by trypsin, in which fifteen protein spots were identified successfully. Among the identified proteins, there were ten over-expressed and five under-expressed proteins in stomach cancer tissues compared with normal tissues. CONCLUSION: In this study, the well-resolved, reproducible 2-DE patterns of human gastric cancer tissue and paired normal tissue were established and optimized and certain differentially-expressed proteins were identified. The combined use of 2-DE and MS provides an effective approach to screen for potential tumor markers.

Differential protein expression in spinal cord tissue of a rabbit model of spinal cordischemia/reperfusion injury

New Zealand rabbits were randomly divided into an ischemia group （occlusion of the abdominal aorta for 60 minutes）, an ischemia-reperfusion group （occlusion of the abdominal aorta for 60 minutes followed by 48 hours of reperfusion） and a sham-surgery group. Two-dimensional gel electrophoresis detected 49 differentially expressed proteins in spinal cord tissue from the ischemia and ischemia/ reperfusion groups and 23 of them were identified by mass spectrometry. In the ischemia group, the expression of eight proteins was up regulated, and that of the remaining four proteins was down regulated. In the ischemia/reperfusion group, the expression of four proteins was up regulated, and that of two proteins was down regulated. In the sham-surgery group, only one protein was detected. In the ischemia and ischemia/reperfusion groups, four proteins overlapped between groups with the same differential expression, including three that were up regulated and one down regulated. These proteins were related to energy metabolism, cell defense, inflammatory mechanism and cell signaling.

Identification of differentially expressed proteins in poplar leaves in-duced by Marssonina brunnea f. sp. Multigermtubi

Black spot disease in poplar is a disease of the leaf caused by fungus. The major pathogen is Marssonina brunnea f. sp. multigermtubi. To date, little is known about the molecular mechanism of poplar （M. brunnea） interaction. In order to identify the proteins related to disease resistance and understand its molecular basis, the clone ＂NL895＂ （P. euramericana CL＂NL895＂）, which is highly resistant to M. brunnea f. sp. multigermtubi, was used in this study. We used two-dimensional gel electrophoresis （2-DE） and mass spectrometry （MS） to identify the proteins in poplar leaves that were differentially expressed in response to black spot disease pathogen, M. brunnea f. sp. multigermtubi. Proteins extracted from poplar leaves at 0, 12, 24, 48, and 72 h after pathogen-inoculation were separated by 2-DE, About 500 reproducible protein spots were detected, of which 40 protein spots displayed differential expression in levels and were subjected to Matrix assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF MS） followed by database searching. According to the function, the identified proteins were sorted into five categories, that is, protein synthesis, metabolism, defense response and unclassified proteins.

Proteomic Identification of Rhythmic Proteins in Maize Seedling Leaves

Plant leaves respond to day/night cycling in a number of physiological ways. At the mRNA level, the expression of some genes changes during the 24 h period. To determine which proteins exhibited a rhythmic pattern of expression, proteomic profiles in maize seedling leaves were analyzed by high-throughput two-dimensional gel electrophoresis, combined with MALDI-TOF MS technology. Of the 464 proteins that were detected with silver staining in a pH range of 4-7, 17 （3.66%） showed clock rhythmicity in their abundance. These proteins belonged to diverse functional groups and proteins involved in photosynthesis and carbon metabolism were over-represented. These findings provide a new perspective on the relationship between the physiological functions of leaves and the clock rhythmic system.

Can proteomics lead to the discovery of real biomarkers for HCC?

The development of proteomics technologies has lead to a great deal of effort being focused on the identification of biomarkers for cancers. Although many papers have reported candidate biomarkers for hepatocellular carcinomas (HCCs) in particular, so far none of these candidate biomarkers have been used either for diagnosis or therapy intreating patients. The question remains: Can proteomics identify real biomarkers for HCCs?

Proteomic identification of potential target proteins regulated by an ASK1-mediated proteolysis pathway

The ASK1 （ARABIDOPSIS SKP1-LIKE） protein is a critical component of the SCF （Skpl-Cullin-F box protein） ubiquitin ligase complexes that recruit target proteins for degradation by the 26S proteosome. To investigate proteins that are affected by the ASK1-mediated proteolysis pathway in Arabidopsis flowers, we compared the proteomes of the Arabidopsis wild type and ask1 mutant flower buds using two-dimensional electrophoresis （2-DE）. Ten protein spots with higher or lower abundance in the ask1 mutant flowers compared to wild type flowers were excised and subjected to further mass spectrometry （MS） analysis. The results showed that they were proteins involved in photomorphogenesis, circadian oscillation, post-translation process, stress-responses and cell expansion or elongation, suggesting that those processes were affected in the ask1 mutant. The transcript levels of these genes were also compared based on the Affymetrix gene chip microarray data. No significant difference was observed for most of the genes, suggesting that the proteins with elevated levels of accumulation in the ask1 mutant could be candidate targets regulated by an ASK 1-mediated proteolysis pathway. These results help to elucidate the pleiotropic functions of ASK1 in Arabidopsis developmental processes and also demonstrate the importance and necessity of studying protein levels with respect to gene functions.

STEM CELLS AND PROTEOMICS

The distinctive features of proteomics are large-scale and high throughput. The key techniques of proteomics are two-dimensional gel electrophoresis, mass spectrometry and bioinformatics. Stem cell can differentiate into all kinds of cells, tissues and organs. There are many proteins and cytokines involved in the process of differentiation. Applying proteomics techniques to the research of the complex process of stem cell differentiation is of great importance to study the mechanism and applications of stem cell differentiation.

Proteomic Analysis of Proteins in the Salivary Glands of the Fed and Unfed Female Tick Rhipicephalus haemaphysaloides

Identification of differentially expressed salivary gland proteins between the fed and unfed female Rhipicephalus haemaphysaloides may obtain valuable functional molecules. In this study, comparative two-dimensional gel electrophoresis （2-DE） and mass spectrometry were used to separate and identify differentially expressed salivary gland proteins between the fed and unfed female R. haemaphysaloides. The soluble proteins from the salivary glands of fed and unfed female R. haemaphysaloides were separated by a sequential extraction method followed by 2-DE and 2-DE images. Image analysis of the gels revealed 1 096 ± 87 protein spots from the fed female ticks and 991 ±64 protein spots from the unfed female ticks. Among those protein spots, about 724 ±34 were present both in the fed and unfed female ticks. Fourteen spots from the fed ticks and six spots from the unfed ticks were selected for peptide mass fingerprinting （PMF） and sequencing assay by mass spectrometry （MS）. Bioinformatic analysis showed that a majority of the differentially expressed proteins were involved in signal transduction, metabolism, and transcriptional regulation. These differentially expressed proteins might be antigen candidates for the development of vaccines against the tick.

Comparative proteomic study of cervical cancer with different radiotherapy sensitivity

Objective： To investigate the proteornic differences between the high-sensitivity （HS） group and low-sensitivity （LS） group of cervical cancer treated by radiotherapy and confirm the radiotherapy sensitivity associated proteins in early cervical cancer. Methods： The fresh carcinoma tissues were collected from 10 untreated cervical cancer patients and preserved in the -80 ℃ refrigeratory. The tissues were classified into two groups： high sensitivity group （HS） and low sensitivity group （LS）, according to their response to radiotherapy. In the first part of our experiment, protein separating was performed by using two-dimensional gel electrophoresis （2-DE） with Amersham 18 cm linear pH 3-10 immobilized pH gradient （IPG） strips. The images of the gels were acquired by the scanner and then analyzed by using PD-quest7.3 software to find the differentially expression protein-spots in each group. Then the differentially expressed protein-spots was incised from the gels and digested by trypsin. The peptide mass fingerprintings （PMF） was acquired by matrix assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF-MS） and the proteins were identified by data searching in the Mascot-database. Part of differentially expression proteins were assayed by Western Blot. Results： Most of the gels were clear and successfully analyzed by PD-quest7.3 software. Most of the protein-spots concentrated on the area of 20-100Kda （Mw） and pH4-8. The average number of the protein-spots was 754 ± 64 in HS group and 777 ±48个 in LS group. The match rate was 87.6% between two groups. Five high expression proteins were found in HS group which were low expression in LS group, 3 high expression protein were found in LS group which were low expression in HS group. Reselts of Western Blot were in coincidence to proteomic result. Conclusion： The 2-DE gels image of HS group and LS group with early cervical cancer tissues treated by radiotherapy are successfully acquired. Some differentially expression proteins between the two groups are further confirmed by immunohistochemical assay.

Identification and significance of differential proteins in A549 cells transfected with HLCDG1

HLCDG1, which locates in chromosome 5q33, is a novel gene cloned recently. The HLCDG1 expression was significantly down regulated in the primary lung carcinoma. It was previously studied that HLCDG1 acted like a tumor suppressor gene. In this paper, proteomics studies were performed to analyze the proteomic expression patterns in the HLCDG1-transfected human lung carcinoma cell line (A549-HLCDG1) and in the control vector-transfecred human lung carcinoma cell line (A549-vector). Employing two dimensional gel eleetrophoresis (2DE), the global pattern of protein expressions in A549-HLCDG1 human lung adenocarcinoma cell line expressing stably HL-CDG1 gene were compared with those of control A549-vector cell line to generate a differential protein expression catalog. Forty-two differentially expressed proteins were screened. Thirteen differential proteins were identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), which were 6 upregulated (MSH5, MOD, MDH precursor, ETFβ, Prxd Ⅵ and JM23) and 7 downregulated (PLC-δ1, hnRNPA2,hnRNPB1, TIM, TCTP, nm23H-1 and PrxdⅤ) proteins in A549-HLCDG1 cells compared to control A549-vector cells. The above identified proteins were involved in energy metabolism, transcription regulation, antioxidation,cell cycle, metastasis, DNA methylation and mismatch repair. Therefore, these differential expression proteins by HLCDG1 transfection may play some important roles for investigation of the biochemical basis of growth suppression of HLCDG1 gene in lung carcinoma cells A549. Further understanding of this data base may provide valuable resources for the developing novel diagnostic markers and therapeutic targets of lung cancer.

Toward a high resolution 2-DE profile of the normal human liver proteome using ultra-zoom gels

The human liver is the largest organ in the body and has many important physiological functions. A global analysis of human liver proteins is essential for a better understanding of the molecular basis of the normal functions of the liver and of its diseases. As part of the Human Liver Proteome Project (HLPP), the goal of the present study was to visualize and detect as many proteins as possible in normal human livers using two-dimensional gel electrophoresis (2-DE). We have constructed a reference map of the proteins of human normal liver that can be used for the comprehensive analysis of the human liver proteome and other related research. To improve the resolution and enhance the detection of low abundance proteins, we developed and optimized narrow pH range ultra-zoom 2-DE gels. High resolution patterns of human liver in pH gradients 4.5-5.5, 5-6, 5.5-6.7, 6-9 and 6-11 are presented. To improve the poor resolution in the alkaline pH range of 2-DE gels, we optimized the isoelectric focusing protocol by including sample application using cup loading at the anode and incorporating 1.2% hydroxyethyl disulfide, 15% 2-propanol and 5% glycerol in the rehydration buffer. Using the optimized protocol, we obtained reproducibly better resolution in both analytical and preparative 2-DE gels. Compared with the 2386 and 1878 protein spots resolved in the wide range 3-10 and 4-7 pH gradients respectively, we obtained 5481 protein spots from the multiple (overlapping) narrow pH range ultra-zoom gels in the range of pH 4.5-9. The visualized reference map of normal human liver proteins presented in this paper will be valuable for comparative proteomic research of the liver proteome.

应答白粉病菌胁迫的黄瓜S17叶片功能蛋白质组学初步分析

Two-dimensional electrophoresis was employed to analyze proteins extracted from sterile and fungal-infected seedling leaves of cucumber S17 at 24 h,48 h and 72 h after inoculating Sphaerotheca fuliginea.Different spots corresponding to induced or repressed proteins were apparent in Coomassie Brilliant Blue G-250 stained 2-DE gels.Eight different proteins of S17 seedling leaves with qualitative changes or relatively high abundance were identified by MALDI-TOF/ TOF and blast in NCBI,including a protein of chloroplast rieske FeS protein,superoxide dismutase ,chromoplast-specific carotenoid-associated protein,translationally controlled tumor protein-related protein,heat shock protein 90,ferredoxin-NADP(H) oxidoreductase,hypothetical protein g5bf and similar to gb|D64087 nuclear matrix constituent protein 1(NMCP1) from Daucus carota.The proteins induced in response to infection were those involved in disease resistance,heat-shock protein,chromosome transcription and translation,or in protein-related photosynthesis and respiration,as well as some unkown proteins.The results provided new insights for pathogen stress response in cucumber leaves,demonstrating the power of the proteomic approach in plant biology studies.