High-resolution Two-dimensional Gel Electrophoresis Research Articles

Proteomic profiling of Arabidopsis G-protein β subunit AGB1 mutant under salt stress.

Salt stress is a limiting environmental factor that inhibits plant growth in most ecological environments. The functioning of G-proteins and activated downstream signaling during salt stress is well established and different G-protein subunits and a few downstream effectors have been identified. Arabidopsis G-protein β-subunit (AGB1) regulates the movement of Na+ from roots to shoots along with a significant role in controlling Na+ fluxes in roots, however, the molecular mechanism of AGB1 mediated salt stress regulation is not well understood. Here, we report the comparative proteome profiles of Arabidopsis AGB1 null mutant agb1-2 to investigate how the absence of AGB1 modulates the protein repertoire in response to salt stress. High-resolution two-dimensional gel electrophoresis (2-DE) showed 27 protein spots that were differentially modulated between the control and NaCl treated agb1-2 seedlings of which seven were identified by mass spectrometry. Functional annotation and interactome analysis indicated that the salt-responsive proteins were majorly associated with cellulose synthesis, structural maintenance of chromosomes, DNA replication/repair, organellar RNA editingand indole glucosinolate biosynthesis. Further exploration of the functioning of these proteins could serve as a potential stepping stone for dissection of molecular mechanism of AGB1 functions during salt stress and in long run could be extrapolated to crop plants for salinity stress management.

The protein extraction method of Metroxylon sagu leaf for high-resolution two-dimensional gel electrophoresis and comparative proteomics

BackgroundSago palm (Metroxylon sagu) is a versatile crop and has been hailed as the next viable commodity in Sarawak, Malaysia. Sago palm can thrive in the harsh swampy peat, from low flooded areas to uplands and in acidic to neutral soils. Sago palm has been neglected and unfortunately, very little is known about the sago palm proteome. This study aimed to determine the best protein extraction method of Metroxylon sagu for the two-dimensional gel electrophoresis (2-DE) and its comparative analysis.ResultsTo perform good proteome research, the most critical step is to establish a method that gives the best quality of extracted total proteins. Five different protein extraction protocols: polyethylene glycol (PEG) fractionation method, phenol extraction method, TCA–acetone method, the combination of phenol and TCA–acetone extraction method and imidazole method were compared to develop an optimized protein extraction method for two-dimensional gel electrophoresis analysis of Metroxylon sagu. The PEG fractionation method was found to give the most reproducible gels with the highest number of spots and highest protein concentration followed by phenol extraction method. The lowest number of spots was observed in the imidazole method. The PEG fractionation method provides improved resolution and reproducibility of 2-DE and reduces the time required to analyze samples. Partitioning Rubisco by polyethylene glycol (PEG) fractionation provides clearer detection of low abundance protein. Hence, the results from this study propose PEG fractionation as the effective protein extraction method for 2-DE proteomic studies of Metroxylon sagu.ConclusionIn this study, the PEG fractionation method is considered as the best extraction method for 2-DE proteomic studies of Metroxylon sagu in terms of yield, gel quality, spot numbers, and quantities of proteins.

Soybean Mutants Lacking Abundant Seed Storage Proteins Are Impaired in Mobilization of Storage Reserves and Germination.

Spontaneous and radiation-induced mutants of soybean, despite loss of abundant seed proteins, have been reported to grow and reproduce normally without any apparent physiological abnormalities. Here, we report the development and characterization of a soybean line (BSH-2) that lacks several abundant seed storage proteins. One-dimensional and high-resolution two-dimensional gel electrophoresis revealed the absence of the α′ and α subunits of β-conglycinin and G1, G2, G4, and G5 glycinin in the newly developed mutant line (BSH-2). Like our earlier developed soybean mutant line (BSH-3), the seeds of BSH-2 also accumulated high levels of free amino acids as compared with wild-type DN47 seeds. An examination of the germination rates revealed that both BSH-2 and BSH-3 had significantly lower germination rates compared with the parent line DN47. Two-dimensional gel electrophoresis analysis demonstrated that these mutants had slower rates of mobilization of seed storage proteins. The delayed mobilization of storage proteins in BSH-2 and BSH-3 seeds was also correlated with a delayed induction of proteolytic activity in the mutants when compared to DN47. Similarly, qRT-PCR analysis revealed distinct expression pattern of genes involved in proteolytic pathway in the mutants when compared to DN47. Transmission electron microscopy observation of soybean seeds at two germination stages revealed striking differences in the breakdown of protein storage vacuoles and lipid bodies in the mutants. Our study demonstrates that BSH-2 and BSH-3 are compromised in mobilization of storage reserves and the absence of abundant storage proteins may affect the seed germination efficiency and post-germinative seedling establishment.

Site-Specific and Quantitative N-Glycan Heterogeneity Analysis of the Charge Isomers of an Anti-VEGF Recombinant Fusion Protein by High-Resolution Two-Dimensional Gel Electrophoresis and Mass Spectrometry.

Glycan modification prompts important concerns about the quality control of biopharmaceutical production. Conbercept is a multiglycosylated recombinant fusion protein drug approved for the treatment of age-related macular degeneration (AMD). With 14 N-glycosites in the molecule and 7 N-glycosites in the monomer, the charge isomer separation and characterization of conbercept pose great challenges due to its enormous heterogeneities. The batch-to-batch stability on the charge isomer distribution and the possible causation of the pattern necessitate the development of effective analytical approaches. Here, the immobilized pH gradient (IPG)-based two-dimensional gel electrophoresis (2-DE) approach was first optimized to achieve high-resolution, high-reproducible separation and preparation of charge isomers. Then, combined with the quantitative analysis strategy of site-specific N-glycan heterogeneity based on the diagnostic MS2 ion (peptides+GlcNAc, Y1 ions) of glycopeptides, an integrated approach for the quantitation of site-specific N-glycan heterogeneities among charge isomers was established. Finally, the quantitation of site-specific N-glycoforms in each of the 2-DE resolved spots were performed, and the results showed that the sialylation tends to increase for gel spots located in the acidic regions. This study provides an effective approach to separate the charge isomers of the heavily glycosylated protein drugs, and to quantitatively explore the site-specific N-glycans dynamics along with the different charge isomers.

Functional Characterization and Proteomic Analysis of Porcine Deltacoronavirus Accessory Protein NS7.

Porcine deltacoronavirus (PDCoV) is an emerging swine enteric coronavirus that causes diarrhea in neonatal piglets. Like other coronaviruses, PDCoV encodes at least three accessory or species-specific proteins; however, the biological roles of these proteins in PDCoV replication remain undetermined. As a first step toward understanding the biology of the PDCoV accessory proteins, we established a stable porcine cell line constitutively expressing the PDCoV NS7 protein in order to investigate the functional characteristics of NS7 for viral replication. Confocal microscopy and subcellular fractionation revealed that the NS7 protein was extensively distributed in the mitochondria. Proteomic analysis was then conducted to assess the expression dynamics of the host proteins in the PDCoV NS7-expressing cells. Highresolution two-dimensional gel electrophoresis initially identified 48 protein spots which were differentially expressed in the presence of NS7. Seven of these spots, including two upregulated and five down-regulated protein spots, showed statistically significant alterations, and were selected for subsequent protein identification. The affected cellular proteins identified in this study were classified into functional groups involved in various cellular processes such as cytoskeleton networks and cell communication, metabolism, and protein biosynthesis. A substantial down-regulation of α-actinin-4 was confirmed in NS7-expressing and PDCoV-infected cells. These proteomic data will provide insights into the understanding of specific cellular responses to the accessory protein during PDCoV infection.

Low-level blast exposure disrupts gliovascular and neurovascular connections and induces a chronic vascular pathology in rat brain

Much concern exists over the role of blast-induced traumatic brain injury (TBI) in the chronic cognitive and mental health problems that develop in veterans and active duty military personnel. The brain vasculature is particularly sensitive to blast injury. The aim of this study was to characterize the evolving molecular and histologic alterations in the neurovascular unit induced by three repetitive low-energy blast exposures (3 × 74.5 kPa) in a rat model mimicking human mild TBI or subclinical blast exposure. High-resolution two-dimensional differential gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry of purified brain vascular fractions from blast-exposed animals 6 weeks post-exposure showed decreased levels of vascular-associated glial fibrillary acidic protein (GFAP) and several neuronal intermediate filament proteins (α-internexin and the low, middle, and high molecular weight neurofilament subunits). Loss of these proteins suggested that blast exposure disrupts gliovascular and neurovascular interactions. Electron microscopy confirmed blast-induced effects on perivascular astrocytes including swelling and degeneration of astrocytic endfeet in the brain cortical vasculature. Because the astrocyte is a major sensor of neuronal activity and regulator of cerebral blood flow, structural disruption of gliovascular integrity within the neurovascular unit should impair cerebral autoregulation. Disrupted neurovascular connections to pial and parenchymal blood vessels might also affect brain circulation. Blast exposures also induced structural and functional alterations in the arterial smooth muscle layer. Interestingly, by 8 months after blast exposure, GFAP and neuronal intermediate filament expression had recovered to control levels in isolated brain vascular fractions. However, despite this recovery, a widespread vascular pathology was still apparent at 10 months after blast exposure histologically and on micro-computed tomography scanning. Thus, low-level blast exposure disrupts gliovascular and neurovascular connections while inducing a chronic vascular pathology.

Obesity Proteomics: An Update on the Strategies and Tools Employed in the Study of Human Obesity.

Proteomics has become one of the most important disciplines for characterizing cellular protein composition, building functional linkages between protein molecules, and providing insight into the mechanisms of biological processes in a high-throughput manner. Mass spectrometry-based proteomic advances have made it possible to study human diseases, including obesity, through the identification and biochemical characterization of alterations in proteins that are associated with it and its comorbidities. A sizeable number of proteomic studies have used the combination of large-scale separation techniques, such as high-resolution two-dimensional gel electrophoresis or liquid chromatography in combination with mass spectrometry, for high-throughput protein identification. These studies have applied proteomics to comprehensive biochemical profiling and comparison studies while using different tissues and biological fluids from patients to demonstrate the physiological or pathological adaptations within their proteomes. Further investigations into these proteome-wide alterations will enable us to not only understand the disease pathophysiology, but also to determine signature proteins that can serve as biomarkers for obesity and related diseases. This review examines the different proteomic techniques used to study human obesity and discusses its successful applications along with its technical limitations.

Differential Musculoskeletal Adaptations to Exercise of the Soleus and Vastus Lateralis

The vastus lateralis (VL) and soleus (SOL) muscles show vigorous changes when exposed to unloading conditions. There is evidence that the SOL muscle shows an increased sensitivity to loading yet has been shown to be resistant to exercise-induced adaptations. PURPOSE: To utilize high-resolution two-dimensional gel electrophoresis combined with mass spectrometry to identify anomalous biomarkers of the SOL muscle. METHODS: Biopsy samples of the VL and SOL muscles were obtained from three healthy, inactive individuals (1 male, 21 yrs, 92.5 kg, 167.5 cm; 2 females, 18 and 19 yrs, 66.6 and 71.7 kg, 153.3 and 161.9 cm respectively). Muscle tissue was homogenized in a bead homogenizer and protein quantified with a DC protein assay. Two-dimensional gel electrophoresis was performed and differences in spot abundance between the two muscles were used to select spots of interest. Proteins of the 24 selected spots were subsequently identified by MALDI-TOF MS/MS scanning and Mascot database searching against Swiss-Prot human protein database. RESULTS: Results from the 2D gel electrophoresis varied across the three subjects. Proteins identified from spots of greater intensity in the VL were myosin light chain isoforms, actin, adenylate kinase isoenzyme, alpha-crystallin B, ankyrin repeat domain-containing protein, plasminogen receptor, G-protein coupled receptor, and troponin I. The main proteins identified in the SOL were related to myoglobin with a protein phosphatase protein also being identified. Western blotting will be conducted to verify the identified proteins. CONCLUSION: This preliminary work has identified differential proteins between the SOL and VL relating to oxygen transport, cytoskeletal components, and energy regulation. Future work should examine changes to the proteome between these two muscle with exercise and unloading. Supported by NIH Grants UL1GM118979, TL4GM118980, and RL5GM118978.

Analysis of DNA topology of EBV minichromosomes in HEK 293 cells.

Simian Virus 40 (SV40) and Epstein-Barr Virus (EBV) are frequently used as model systems to study DNA replication. Their genomes are both circular duplex DNAs organized in a single replicon where replication initiates at a precise site upon binding of a specific protein: the large tumor (T) antigen for SV40 and the Epstein-Barr Nuclear Antigen 1 (EBNA-1) for EBV. Despite the abundant information available on the genetics and biochemistry of the replication process in these systems, little is known about the changes in DNA topology that take place as molecules are transfected into eukaryotic cells, assembled into chromatin and bind initiator proteins to start replication. Here we used high-resolution two-dimensional agarose gel electrophoresis to demonstrate that in Human Embryonic Kidney (HEK) 293 cells, minichromosomes of almost the same mass carrying either the SV40 or the EBV replication origin showed similar topological features. The patterns were very similar regardless of the initiator proteins. We also showed that in a hybrid minichromosome, pEco3’Δ, that initiates replication from the SV40 origin, the presence of EBNA-1 and its putative binding to the EBV “family of repeats” induces no significant topological change. These observations challenge the idea that binding of EBNA-1 to oriP could induce negative supercoiling and favor a model suggesting that it binds to oriP in a two-step process where only the second step causes structural changes in a transient cell cycle specific manner.

DIGE Analysis Software and Protein Identification Approaches.

DIGE is a high-resolution two-dimensional gel electrophoresis method, with excellent dynamic range obtained by fluorescent tag labeling of protein samples. Scanned images of DIGE gels show thousands of protein spots, each spot representing a single or a group of protein isoforms. By using commercially available software, each protein spot is defined by an outline, which is digitized and correlated with the quantity of proteins present in each spot. Software packages include DeCyder, SameSpots, and Dymension 3. In addition, proteins of interest can be excised from post-stained gels and identified with conventional mass spectrometry techniques. High-throughput mass spectrometry is performed using sophisticated instrumentation including matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF), MALDI-TOF/TOF, and liquid chromatography tandem mass spectrometry (LC-MS/MS). Tandem MS (MALDI-TOF/TOF or LC-MS/MS), analyzes fragmented peptides, resulting in amino acid sequence information, especially useful when protein spots are low abundant or where a mixture of proteins is present.

High-throughput proteome analysis reveals changes of primary metabolism and energy production under artificial aging treatment in Glycine max seeds

This study was conducted to obtain basic information on protein profile changes by artificial aging in soybean seeds. Seed proteins were extracted using the protamine sulfate precipitation method, which improves the detection of low-abundance proteins (LAPs) by depleting the major seed storage proteins . Isolated proteins were separated by high-resolution two-dimensional gel electrophoresis (2-DE), and differentially modulated protein spots were identified by MALDI-TOF/TOF. A total of 33 differential proteins were identified of which 31 and 2 showed decreased and increased abundances, respectively. Functional annotation of the identified proteins revealed that proteins were mainly associated with primary metabolism (55%) and response to stimulus (20.9%). Proteins with increased abundance were associated with nutrient reservoir activity (spots 5, 10), while the decreased abundance proteins were mainly involved in the primary metabolism such as carbohydrate metabolic process (spots 1–3, 11), protein folding (spots 6–9, 33), glucose metabolic process (spot 25) oxidoreductase activity (spots 19–24), UDP-glucose pyrophosphorylase activity (spots 12, 13). These results provide information about proteome changes, especially, LAPs during artificial seed aging treatment.

Proteomic profiling of pretreatment serum from HIV-infected patients identifies candidate markers predictive of lymphoma development.

HIV-infected individuals have an increased risk of developing lymphoma. We sought to identify markers predictive of lymphoma development by comparing protein expression patterns in serum obtained at the time of HIV diagnosis from patients who later developed malignant lymphoma or benign lymphadenopathy, with samples from patients with no subsequent history of neoplasia. All patients were identified retrospectively from the Danish HIV cohort. Serum samples (N = 21), obtained at time of HIV diagnosis, were subjected to high-resolution two-dimensional gel electrophoresis. Differentially expressed proteins were identified by liquid chromatography-tandem mass spectrometry. A tissue microarray, containing diagnostic HIV-lymphoma tissue samples (N = 40), was used to investigate immunohistochemical expression of markers in tumoural lesions. Fourteen differentially expressed protein spots were detected. Using principal components analysis, spots containing immunoglobulin J chain, apolipoprotein A-I, procollagen C-endopeptidase enhancer-1 and complement C4-A were associated with lymphoma development (P < 0.0001). Serum amyloid A-2 was increased almost 10-fold in patients with subsequent lymphoma compared with patients without subsequent lymphoma. In the tissue microarray, amyloid A was widely expressed, and high expression showed a tendency towards inferior outcome (log-rank 0.073). We identified several differentially expressed protein spots present already at the time of HIV diagnosis. Analysis of biological differences correlating to lymphoma development at this early stage of a possible malignant transformation may lead to the identification of predictive markers. Further investigation of the potential clinical application of differentially expressed proteins as risk stratification markers for monitoring HIV-positive individuals is warranted.

Differential Expression of Middle Silk Gland Proteins Caused by Cold Stress in Philosamia ricini

This study reports differentially expressed proteins in the middle silkglands of normal and cold stress treated 5th instar Philosamia ricini larvae by using high resolution two-dimensional polyacrylamide gel electrophoresis. About 300 protein spots were resolved in both type of the larvae. Most of the proteins were shown to be distributed in the area from 20 to 70 kDa ranging between pH 4 and 8. Six proteins showed considerably decreased expression in cold stress treated samples. Three proteins displayed increased level of expression after cold stress treatment, while two other proteins were expressed exclusively in cold stress treated silkgland tissues.

Characterization of the Tumor Secretome from Tumor Interstitial Fluid (TIF).

Tumor interstitial fluid (TIF) surrounds and perfuses bodily tumorigenic tissues and cells, and can accumulate by-products of tumors and stromal cells in a relatively local space. Interstitial fluid offers several important advantages for biomarker and therapeutic target discovery, especially for cancer. Here, we describe the most currently accepted method for recovering TIF from tumor and nonmalignant tissues that was initially performed using breast cancer tissue. TIF recovery is achieved by passive extraction of fluid from small, surgically dissected tissue specimens in phosphate-buffered saline. We also present protocols for hematoxylin and eosin (H&E) staining of snap-frozen and formalin-fixed, paraffin-embedded (FFPE) tumor sections and for proteomic profiling of TIF and matched tumor samples by high-resolution two-dimensional gel electrophoresis (2D-PAGE) to enable comparative analysis of tumor secretome and paired tumor tissue.

Deceptive responsive genes in gel-based proteomics

The standard method of the global quantitative analysis of gene expression at the protein level combines high-resolution two-dimensional gel electrophoresis (2DE) with mass spectrometric identification of protein spots. One of the major concerns with the application of gel-based proteomics is the need for the analytical and biological accuracy of the datasets. We mathematically and empirically simulated the possibility of the technical regulations of gene expression using 2DE. Our developed equation predicted a detectable alteration in the quantity of protein spots in response to a new protein added in, with various amounts. Testing the predictability of the developed equation, we observed that a new protein could form deceptive expression profiles, classified using prevalent tools for the analysis of 2DE results. In spite of the theoretically predicted overall reduction of proteins that resulted from adding the new protein, the empirical data revealed differential amount of proteins when various quantities of the new protein were added to the protein sample. The present work emphasize that employment of 2DE would not be a reliable approach for biological samples with extensive proteome alterations such as the developmental and differentiation stages of cells without depletion of high abundant proteins.

Functional characterization and proteomic analysis of the nucleocapsid protein of porcine deltacoronavirus

Porcine deltacoronavirus (PDCoV) is a newly discovered enterotropic swine coronavirus that causes enteritis and diarrhea in piglets. Like other coronaviruses, PDCoV commonly contains 4 major structural proteins: spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins. Among these, the N protein is known to be the most abundant and multifunctional viral component. Therefore, as the first step toward understanding the biology of PDCoV, the present study investigated functional characteristics and expression dynamics of host proteins in a stable porcine cell line constitutively expressing the PDCoV N protein. Similar to N proteins of other coronaviruses, the PDCoV N protein was found to interact with itself to form non-covalently linked oligomers and was mainly localized to the nucleolus. We then assessed alterations in production levels of proteins in the N-expressing PK (PK-PDCoV-N) cells at different time points by means of proteomic analysis. According to the results of high-resolution two-dimensional gel electrophoresis, a total of 43 protein spots were initially found to be differentially expressed in PK-PDCoV-N cells in comparison with control PK cells. Of these spots, 10 protein spots showed a statistically significant alteration, including 8 up-regulated and 2 down-regulated protein spots and were picked for subsequent protein identification by peptide mass fingerprinting following matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The affected cellular proteins that we identified in this study were classified into the functional groups involved in various cellular processes such as cell division, metabolism, the stress response, protein biosynthesis and transport, cytoskeleton networks and cell communication. Notably, two members of the heat shock protein 70 family were found to be up-regulated in PK-PDCoV-N cells. These proteomic data will provide insights into the specific cellular response to the N protein during PDCoV infection.

Direct Evidence for the Formation of Precatenanes during DNA Replication

The dynamics of DNA topology during replication are still poorly understood. Bacterial plasmids are negatively supercoiled. This underwinding facilitates strand separation of the DNA duplex during replication. Leading the replisome, a DNA helicase separates the parental strands that are to be used as templates. This strand separation causes overwinding of the duplex ahead. If this overwinding persists, it would eventually impede fork progression. In bacteria, DNA gyrase and topoisomerase IV act ahead of the fork to keep DNA underwound. However, the processivity of the DNA helicase might overcome DNA gyrase and topoisomerase IV. It was proposed that the overwinding that builds up ahead of the fork could force it to swivel and diffuse this positive supercoiling behind the fork where topoisomerase IV would also act to maintain replicating the DNA underwound. Putative intertwining of sister duplexes in the replicated region are called precatenanes. Fork swiveling and the formation of precatenanes, however, are still questioned. Here, we used classical genetics and high resolution two-dimensional agarose gel electrophoresis to examine the torsional tension of replication intermediates of three bacterial plasmids with the fork stalled at different sites before termination. The results obtained indicated that precatenanes do form as replication progresses before termination.

Novel prognostic markers revealed by a proteomic approach separating benign from malignant insulinomas

The prognosis of pancreatic neuroendocrine tumors is related to size, histology and proliferation rate. However, this stratification needs to be refined further. We conducted a proteome study on insulinomas, a well-defined pancreatic neuroendocrine tumor entity, in order to identify proteins that can be used as biomarkers for malignancy. Based on a long follow-up, insulinomas were divided into those with metastases (malignant) and those without (benign). Microdissected cells from six benign and six malignant insulinomas were subjected to a procedure combining fluorescence dye saturation labeling with high-resolution two-dimensional gel electrophoresis. Differentially expressed proteins were identified using nano liquid chromatography–electrospray ionization/multi-stage mass spectrometry and validated by immunohistochemistry on tissue microarrays containing 62 insulinomas. Sixteen differentially regulated proteins were identified among 3000 protein spots. Immunohistochemical validation revealed that aldehyde dehydrogenase 1A1 and voltage-dependent anion-selective channel protein 1 showed significantly stronger expression in malignant insulinomas than in benign insulinomas, whereas tumor protein D52 (TPD52) binding protein was expressed less strongly in malignant insulinomas than in benign insulinomas. Using multivariate analysis, low TPD52 expression was identified as a strong independent prognostic factor for both recurrence-free and overall disease-related survival.

Proteomic Analysis Identifies Outcome-Predictive Clusters in Patients with Peripheral T-Cell Lymphoma, Not Otherwise Specified

Introduction: Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) is a heterogeneous group of mature T-cell lymphomas, probably composed by different biologically related subsets that have not yet been conclusively identified. In the WHO classification, PTCL-NOS accounts for 25-30% of all mature T-/NK-cell malignancies. The clinical outcome is generally poor with a 5-yr overall survival of 30-35% after conventional treatment strategies. The aim of the study was to apply proteomic analysis in PTCL-NOS and to use the protein expression profiles to characterize clinically relevant subsets within this heterogeneous entity by means of unsupervised cluster analysis.Methods: Archival frozen tumor tissue samples from 20 patients diagnosed with PTCL-NOS from 1991 to 2010 were analyzed for protein expression by high-resolution two-dimensional gel electrophoresis. Individual protein spots were visualized with fluorescence staining and the expression profiles were identified. All patients were homogeneously treated with curatively intended anthracycline-containing combination regimens. Clinico-pathological features were obtained from the Danish Lymphoma Registry (LYFO) and from patient records. Hyperplastic tonsils from healthy adults were included as reference tissue (n=8). Principal component analysis and unsupervised hierarchical cluster analysis were performed on the basis of the protein expression profiles. Differentially expressed (two-fold or higher, Mann-Whitney U-test) proteins between the detected clusters were identified by liquid chromatography - tandem mass spectrometry.Results: Unsupervised cluster analysis defined three distinct clusters: one containing all reference samples and two additional ones further subdividing the PTCL-NOS cases in two separate subsets. Patients from these two PTCL-NOS subsets had significantly different responses to treatment and survival (p = 0.001). The differentially expressed proteins were primarily involved in (i) promotion of tumor growth, (ii) regulation of cellular metabolism, and (iii) immune responses.Conclusion: Proteomic analysis identified shared protein expression patterns and potential prognostic markers in subsets of PTCL-NOS. DisclosuresNo relevant conflicts of interest to declare.

Comparative proteomic analysis of tobacco expressing cyanobacterial flavodoxin and its wild type under drought stress

Tobacco plants expressing cyanobacterial flavodoxin (Fld) show enhanced tolerance to a wide range of abiotic stresses including drought, temperature and UV. The mechanisms of adaptation to stress conditions under Fld expression are largely unknown. Here, we applied comparative proteomic analysis to uncover the changes in the proteome profile of Fld-expressing plants in response to drought stress. Using high-resolution two-dimensional gel electrophoresis, we were able to detect 930 protein spots and compare their abundance. We found changes up to 1.5 fold for 52 spots under drought in transgenic and/or wild type plants. Using combined MALDI-TOF/TOF and ESI-Q/TOF analysis 39 (24 in wild type, 11 in transgenic, and 4 in both) drought-responsive proteins (DRPs) could be identified. The majority of DRPs are known to be involved in photosynthesis, carbohydrate and energy metabolism, amino acid and protein synthesis and processing, and oxidative stress responses. Among candidate DRPs, the abundance of remurin, ferredoxin-NADP reductase, chloroplast manganese stabilizing protein-II, phosphoglycerate mutase, and glutathione S-transferase decreased in drought stressed Fld-tobacco while S-formylglutathione hydrolase and pyridoxine biosynthesis protein abundance increased. In wild type plants, drought caused a reduction of proteins related to carbohydrate metabolism. These results suggest that the stress tolerance conferred by Fld expression is strongly related to control mechanisms regarding carbohydrate and energy metabolism as well as oxidative stress responses.