Two-dimensional Sodium Dodecyl Sulfate Research Articles

Protein expression patterns in hek-Blue™ - Cells treated with Clinacanthus nutans extracts

Background: Clinacanthus nutans (CN) is a small shrub native to tropical Asia known for their anti-oxidant, anti-inflammation, anti-cancer, and anti-viral activities. Objectives: This study aimed to investigate the effect of CN extract on human embryonic kidney cell line (HEK-Blue™-4) in a proteomic perspective. Materials and Methods: Comparative proteomic profiling through two-dimensional sodium dodecyl sulfate gel electrophoresis was performed on HEK-Blue™-4 treated with CN leaf polar extract. Results: We successfully identified seven upregulated proteins, of which five promoted the growth of the HEK-Blue™-4 cells. Interestingly, a potent antioxidant enzyme which neutralizes reactive oxygen or nitrogen species, peroxiredoxin-1 was also upregulated in HEK-Blue™-4 cell lines after treatment with CN leaf polar extract. Conclusion: CN leaf polar extract promotes the growth of HEK-Blue™-4 cells and induced the expression of peroxiredoxin-1, which protects the cells from reactive oxygen species during the inflammation process.

2D SDS PAGE in Combination with Western Blotting and Mass Spectrometry Is a Robust Method for Protein Analysis with Many Applications.

Two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2D SDS PAGE) is a method that separates proteins according to their isoelectric points in the first dimension and molecular masses in the second dimension. Evidence is provided that 2D SDS PAGE is reproducible, robust and compatible with SDS in both dimensions including isoelectric focusing in tube gels, the first dimension. The 2D gel pattern of rat liver microsomes shows more detail and sharper spot outlines when dissolved in SDS buffer with heating than in urea buffer and is better yet when dissolved in a mixture of both buffers. Quantification of 60 proteins in rat liver cytosol over a wide range of pI and MW gave linear plots of spot density versus total protein for loads of 200, 400 and 600μg protein dissolved in SDS buffer and run in triplicate on 2D gels (Average R2=0.987). Examples of biomedical applications are provided in which 2D proteins of interest found by comparing stained or western blotted 2D gel patterns were identified by mass spectrometry (MS).

Counterion Dye Staining of Proteins in One- and Two-Dimensional Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis and Tryptic Gel Digestion of Stained Protein for Mass Spectrometry.

A fast and matrix-assisted laser desorption/ionization-mass spectrometry compatible protein staining method in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis is described. It is based on the counterion dye staining method that employs oppositely charged two dyes, zincon and ethyl violet to form an ion-pair complex. The protocol including fixing, staining, and quick washing steps can be completed in 1-1.5h depending upon gel thickness. It has the sensitivity comparable to the colloidal Coomassie Brilliant Blue G stain using phosphoric acid as a component of staining solution (4-8ng). The counterion dye stain does not induce protein modifications that complicate interpretation of peptide mapping data from mass spectrometry. Considering the speed, sensitivity, and compatibility with mass spectrometry, the counterion dye stain may be more practical than any other dye-based protein stains for routine proteomic researches.

Formation and morphogenesis of a cuttlebone's aragonite biomineral structures for the common cuttlefish (Sepia officinalis) on the nanoscale: Revisited

This study describes and examines the structural and morphological properties of the hierarchically organized, aragonite cuttlebone forms for the common cuttlefish (Sepia officinalis, L.), including its main structural parts, the dorsal shield, and the chambers. Specifically, it complements the mechanism for the self-organized formation of aragonite, identifies the presence, and determines the role of soluble organic matrix (SOM) proteins in the morphogenesis of the cuttlebone’s biomineral structures on the nanoscale. The structure and morphology of the cuttlebone were examined using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), and their thermal properties by thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA). Proteins from the SOM were investigated using two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2D-PAGE), matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS), nano liquid chromatography tandem mass spectrometry (nano-LC ESI-MS) and Edman degradation. The results showed that the cuttlebone exhibited several diverse biomineral structures characterized by complex morphologies. Their formation is governed by the organic matrix, particularly proteins, which at the earliest stage of development provide templates for the initial extracellular nucleation of the aragonite nanocrystals. This is followed by a bottom-up morphogenesis, based on the nanoscale oriented aggregation and coalescence of primarily formed aragonite nanograins, which results in the hierarchically organized, nanostructured, aragonite forms. The molecular masses of the most pronounced SOM proteins from the dorsal shield were about 10, 15, 40 and 60kDa, while from the chambers they were 10, 20, 25, 30 and 45kDa. Peptide fragments corresponding to Sep7, Sep8, chitin synthase 1, ficoline-2, polyubiquitin and the ubiquitin carboxyl-terminal hydrolase 32-like protein were detected in the SOM, with these proteins having functional properties related to the biomineralization processes. In general, there are mostly acidic proteins present in alternatively glycosylated forms, which are common attributes of biomineralization-related proteins.

Cacao Phylloplane: The First Battlefield against Moniliophthora perniciosa, Which Causes Witches' Broom Disease.

The phylloplane is the first contact surface between Theobroma cacao and the fungus Moniliophthora perniciosa, which causes witches' broom disease (WBD). We evaluated the index of short glandular trichomes (SGT) in the cacao phylloplane and the effect of irrigation on the disease index of cacao genotypes with or without resistance to WBD, and identified proteins present in the phylloplane. The resistant genotype CCN51 and susceptible Catongo presented a mean index of 1,600 and 700 SGT cm-2, respectively. The disease index in plants under drip irrigation was reduced by approximately 30% compared with plants under sprinkler irrigation prior to inoculation. Leaf water wash (LWW) of the cacao inhibited the germination of spores by up to 98%. Proteins from the LWW of CCN51 were analyzed by two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by tandem mass spectrometry. The gel showed 71 spots and identified a total of 42 proteins (28 from the plant and 14 from bacteria). Proteins related to defense and synthesis of defense metabolites and involved in nucleic acid metabolism were identified. The results support the hypothesis that the proteins and water-soluble compounds secreted to the cacao phylloplane participate in the defense against pathogens. They also suggest that SGT can contribute to the resistance of cacao.

Allergy to grass pollen: mapping of Dactylis glomerata and Phleum pratense allergens for dogs by two-dimensional immunoblotting.

IntroductionMuch less is known about grass-pollen allergens to dogs, when compared with humans. Genetic-based patterns might play an important role in sensitization profiles, conditioning the success of allergen-specific immunotherapy.AimMapping of Dactylis glomerata (D. glomerata) and Phleum pratense (P. pratense) allergens for grass pollen-sensitized atopic dogs, for better understanding how individual allergograms may influence the response to grass-pollen immunotherapy.Material and methodsTo identify D. glomerata and P. pratense allergoms for dogs, 15 individuals allergic to grass pollen and sensitized to D. glomerata and P. pratense were selected. D. glomerata and P. pratense proteomes were separated by isoelectric focusing (IEF), one-dimensional (1-D) and two-dimensional (2-D) sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Separated proteins were blotted onto Polyvinylidene difluoride (PVDF) membranes and allergens were identified by patient sera IgE in Western Blotting (WB).ResultsIn D. glomerata, 17 allergens were identified from IEF and 11 from 1-D SDS-PAGE, while from P. pratense, 18 and 6 allergens were identified, respectively. From 2-D SDS-PAGE 13 spots were identified from D. glomerata and 27 from P. pratense.ConclusionsSeveral similarities were found between dog and human D. glomerata and P. pratense sensitization profiles but no relationship between clinical signs and a specific pattern of allergen recognition was observed. Similarities were found in each patient pattern of sensitization between D. glomerata and P. pratense, also suggesting cross-reactive phenomena. Further molecular epidemiology approach is needed to understand the role of the sensitization pattern in allergen-specific immunotherapy effectiveness in grass-pollen allergic dogs.

Proteomic Evaluation of Biomarkers to Determine the Postmortem Interval

ABSTRACTProteomics separates and analyzes proteins for investigation at the cellular level in regard to disease processing by analyzing the proteins’ expression, function, structure, post-translational modification, and protein–protein interaction. In general forensic investigations, the postmortem interval was evaluated by measuring changes in body temperature after death, along with forensic entomological knowledge. These investigations may be restrictive and subjective because of external factors. The objectives of this study are to sort biomarker candidates and develop a direct postmortem-interval characterization method using proteomics through analyzing and tracking down proteins in the deceased that change in accordance with the postmortem interval. The liver and heart tissues of rats were collected for protein extraction in the 24-h interval following death, and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis was conducted based on the isoelectric point and the molecular weight for separation. To validate protein spot changes on the gel, the stained electrophoresis gels were scanned and converted to digital images. Through image analysis, 14 liver proteins and 12 heart proteins were sorted and classified into four groups based on pattern changes. These proteins containing spots were extracted from the gel and analyzed by high-performance liquid chromatography with tandem mass spectrometry. Finally, 26 protein postmortem-interval relevant biomarker candidates were identified using software. Some of the proteins were muscle proteins while others were oxidation-related proteins. This study presents a new approach to the postmortem-interval research using proteomics and could be substituted for postmortem-interval evaluation.

Developments on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for identifying dissolved and particulate proteins in seawater after two-dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis

Two-dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis (2D-SDS–PAGE) was applied to separate protein in dissolved organic matter (DOM) and in particulate organic matter (POM) from seawater. Dissolved proteins were concentrated and purified using tangential flow ultrafiltration (UF) and centrifugal ultrafiltration. Twelve proteins (Sypro Ruby stained 2D-gels) exhibited isoelectric points (pIs) ranging from 3.5 to 6.0, and molecular weights (MWs) within the 10–50kDa range.Marine plankton were concentrated by centrifugation, and proteins were isolated by grounding the biomass under liquid nitrogen before several washing stages [10% trichloroacetic acid (TCA) in acetone followed by 0.1M ammonium acetate in 80/20 methanol/water] and extraction with a phenol–SDS mixture. 2D-SDS–PAGE showed the presence of approximately 140 different protein spots (Sypro Ruby stained 2D-gels), and plankton proteins exhibited MWs ranging from 12 to 150kDa with pIs between 3 and 10.Electrophoretically separated proteins were further enzymatically in-gel digested (trypsin) and analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Dissolved proteins in eight of the twelve resolved spots were identified by mass mapping (eleven different proteins were assigned); whereas, seven of the twenty-four resolved plankton protein spots were identified, and four different proteins were successfully assigned.

House-dust mite allergy: mapping of Dermatophagoides pteronyssinus allergens for dogs by two-dimensional immunoblotting.

IntroductionSpecific immunotherapy has shown to be very useful for allergy control in dogs, with a common success rate ranging from 65% to 70%. However, this efficacy could probably be improved and the identification of individual allergomes, with the choice of more adequate molecular allergen pools for specific immunotherapy, being the strategy.AimTo map Dermatophagoides pteronyssinus (Der p) allergens for mite-sensitized atopic dogs, for better understanding how individual allergograms may influence the response to house-dust mite immunotherapy.Material and methodsTo identify the Der p mite allergome for dogs, 20 individuals allergic to dust-mites and sensitized to Der p, were selected. The extract from Der p was submitted to isoelectric focusing (IEF), one-dimensional (1-D) and two-dimensional (2-D) sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Separated proteins were blotted onto polyvinylidene difluoride (PVDF) membranes and immunoblottings were performed with patient sera. Allergen-bound specific IgE was detected.ResultsEleven allergens were identified from isoelectric focusing (IEF), as well as from 1-D SDS PAGE. From 2-D SDS-PAGE, 24 spots were identified.ConclusionsSeveral similarities were found between dog and human allergograms and no absolute correlation between sensitization and allergy was observed either. As in humans, different individual allergograms do not seem to implicate different clinical patterns, but may influence the response to specific immunotherapy. The molecular epidemiology approach in veterinary allergy management, by the characterization of individual patients’ allergoms and by choosing the best molecular allergen pool for each patient could also improve the efficacy of allergy immunotherapy.

Proteomic identification of calcium-binding chaperone calreticulin as a potential mediator for the neuroprotective and neuritogenic activities of fruit-derived glycoside amygdalin

Amygdalin is a fruit-derived glycoside with the potential for treating neurodegenerative diseases. This study was designed to identify the neuroprotective and neuritogenic activities of amygdalin. We initially demonstrated that amygdalin enhanced nerve growth factor (NGF)-induced neuritogenesis and attenuated 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in rat dopaminergic PC12 cells. To define protein targets for amygdalin, we selected a total of 11 mostly regulated protein spots from two-dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis gels for protein identification by matrix-assisted laser desorption/ionization–time-of-flight–mass spectrometry. We verified the effect of amygdalin on six representative proteins (i.e., calreticulin, Hsp90β, Grp94, 14-3-3η, 14-3-3ζ/δ and Rab GDI-α) for biological relevance to neuronal survival and differentiation. Calcium-binding chaperone calreticulin is of special interest for its activities to promote folding, oligomeric assembly and quality control of proteins that modulate cell survival and differentiation. We transiently knocked down calreticulin expression by specific siRNA and studied its effect on the neuroprotective and neuritogenic activities of amygdalin. We found that amygdalin failed to enhance NGF-induced neuritogenesis in calreticulin-siRNA transfected cells. On the other hand, amygdalin rescued 6-OHDA-induced loss of calreticulin expression. We also found that amygdalin increased the intracellular calcium concentration possibly via inducing calreticulin. Collectively, our results demonstrated the role of calreticulin in mediating the neuroprotective and neuritogenic activities of amygdalin.

Upregulation of SET expression by BACE1 and its implications in Down syndrome.

Down syndrome (DS) is one of the most common genetic diseases. Patients with DS display growth delay and intellectual disabilities and develop Alzheimer's disease (AD) neuropathology after middle age, including neuritic plaques and neurofibrillary tangles. Beta-site amyloid β precursor protein (APP) cleaving enzyme 1 (BACE1), essential for Aβ production and neuritic plaque formation, is elevated in DS patients. However, its homolog, β-site APP cleaving enzyme 2 (BACE2), functions as θ-secretase and plays a differential role in plaque formation. In this study, by using Two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2D SDS-PAGE) and LC-MS/MS proteomic profiling analysis, we found that the SET oncogene protein (SET) expression was associated with BACE1 but not BACE2. SET protein was increased in BACE1 overexpressing cells and was markedly reduced in the BACE1 knockout mice. We found that the overexpression of BACE1 or SET significantly inhibited cell proliferation. Moreover, knockdown of SET in BACE1 overexpression cells significantly rescued BACE1-induced cell growth suppression. Furthermore, both BACE1 and SET protein levels were increased in Down syndrome patients. It suggests that BACE1 overexpression-induced SET upregulation may contribute to growth delay and cognitive impairment in DS patients. Our work provides a new insight that BACE1 overexpression not only promotes neuritic plaque formation but may also potentiate neurodegeneration mediated by SET elevation in Alzheimer-associated dementia in DS.

Comparative Analysis of Serum Proteins in Relation to Rheumatoid Arthritis and Chronic Periodontitis

Rheumatoid arthritis (RA) and chronic periodontitis (CP) are chronic inflammatory conditions and share many pathologic features. The common molecular pathogenesis of the two inflammatory diseases is unclear. The aim of the present study is to evaluate serum protein profiles specific for patients with RA and CP by a comprehensive proteomic analysis. The study participants were: 10 patients with RA, 10 patients with CP, 10 patients with RA and CP, and 10 healthy controls. All groups were balanced for age, sex, and smoking status. Serum protein spot volume was examined with two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. Proteins with significant differences in abundance among the four groups were determined with computer image analysis and identified with mass spectrometry and protein databases. A total of 1,694 protein spots were obtained in sera of the four groups. Seven spots were significantly different in abundance among the four groups. Of these, three spots (complement component 3, complement factor H, and ceruloplasmin) were significantly different in the RA+CP group compared with the other three groups (P <0.05). The similar profiles of complement component 3, complement factor H, and ceruloplasmin were observed by enzyme-linked immunosorbent assay. These results suggest that patients with RA and CP may exhibit three serum proteins with different abundance compared with healthy controls and patients with RA only or CP only.

Galectin-4, a Novel Predictor for Lymph Node Metastasis in Lung Adenocarcinoma

Metastasis is still a major issue in cancer, and the discovery of biomarkers predicting metastatic capacity is essential for the development of better therapeutic strategies for treating lung adenocarcinoma. By using a proteomic approach, we aimed to identify novel predictors for lymph node metastasis in lung adenocarcinoma. Two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis showed 6 spots differentially expressed between lymph node metastasis-positive and lymph node metastasis-negative groups in a discovery set. Subsequent mass spectrometry showed that 2 of these spots were derived from galectin-4, and western blot analysis confirmed the overexpression of galectin-4 in metastatic samples. The predictive value of galectin-4 was confirmed by immunohistochemical analysis for a validation set consisting of 707 surgically resected specimens of lung adenocarcinomas (stages I to IV). We observed that 148 lung adenocarcinomas (20.9%) expressed galectin-4, which was significantly associated with variables of disease progression such as tumor size (p<0.0001), pleural invasion (p = 0.0071), venous invasion (p = 0.0178), nodal status (p = 0.0007), and TNM stage (p<0.0001). By the multivariate analysis, Galectin-4 expression was revealed as one of the independent predictor for lymph node metastasis, together with solid predominant and micropapillary histologic pattern. Furthermore, galectin-4 expression was revealed to be an independent predictor for lymph node metastasis and an adverse survival factor in patients with lung adenocarcinoma of acinar predominant type. Galectin-4 plays an important role in metastatic process of lung adenocarcinoma. Immunohistochemical testing for galectin-4 expression may be useful together with the detection of specific histology to predict the metastatic potential of lung adenocarcinoma.

Proteomic Analysis of Intracellular and Membrane Proteins From Voriconazole-Resistant Candida glabrata

ObjectivesThe proteomic analysis of voriconazole resistant Candida glabrata strain has not yet been investigated. In this study, differentially expressed proteins of intracellular and membrane fraction from voriconazole-susceptible, susceptible dose-dependent (S-DD), resistant C. glabrata strains were compared with each other and several proteins were identified. MethodsThe proteins of intracellular and membrane were isolated by disrupting cells with glass bead and centrifugation from voriconazole susceptible, S-DD, and resistant C. glabrata strains. The abundance of expressed proteins was compared using two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis and proteins showing continuous twofold or more increase or reduction of expression in resistant strains compared to susceptible and S-DD strain were analyzed by liquid chromatography/mass spectrometry-mass spectrometry method. ResultsOf 34 intracellular proteins, 15 proteins showed expression increase or reduction (twofold or more). The identified proteins included regulation, energy production, carbohydrate transport, amino acid transport, and various metabolism related proteins. The increase of expression of heat shock protein 70 was found. Among membrane proteins, 12, 31 proteins showed expression increase or decrease in the order of susceptible, S-DD, and resistant strains. This expression included carbohydrate metabolism, amino acid synthesis, and response to stress-related proteins. In membrane fractions, the change of expression of 10 heat shock proteins was observed, and 9 heat shock protein 70 (Hsp70) showed the reduction of expression. ConclusionThe expression of Hsp70 protein in membrane fraction is related to voriconazole resistant C. glabrata strains.

Alteration in protein profile of Pseudomonas aeruginosa (PTSOX4) coated with magnetic Fe3O4 nanoparticles

Abstract One of the remarkable features of bacterial species is their capacity for rapid growth when the appropriate environmental condition for growth is provided. Some bacteria, during their growth period, encounter stress factors in their natural environments, such as limitation in growth bioavailability, heat shock, heavy metal, etc. One stress factor not studied is the effect of magnetic Fe3O4 nanoparticles on bacterial growth rate. The effect of magnetic Fe3O4 nanoparticles on the protein profiles of genetically engineered bacterial strain Pseudomonas aeruginosa (PTSOX4), a strain with biological desulfurization characteristic, was investigated. The magnetic Fe3O4 nanoparticles were synthesized using co-sedimentation method, and their morphology was observed by scanning electron microscopy (SEM). The topography of magnetic Fe3O4 nanoparticles was detected by X-ray diffraction, and the average nanoparticle size measured was 40 to 50 nm. The bacterial cells were coated with magnetic nanoparticles, and the SEM electrographs of the bacterial cells indicated that the nanoparticles were uniformly coated on the cell surface. Proteins from both uncoated and coated bacterial cells were extracted by sonication and subjected to two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. Some novel protein bands appeared in the protein profiles of coated bacterial cells; however, some protein bands disappeared. The two-dimensional gel electrophoresis results highlighted the presence of two different polypeptide groups, with molecular weights of 30 to 56 kDa and 56 to 65 kDa.

Effects of a TASER® conducted energy weapon on the circulating red-blood-cell population and other factors in Sus scrofa

In previous studies hematocrit has been consistently increased in an anesthetized animal model after exposures to TASER(®) conducted energy weapons (CEWs). In the present study we analyzed changes in blood cell counts and red blood cell membrane proteins following two 30-s applications of a TASER C2 device (which is designed for civilian use). Hematocrit increased significantly from 33.2 ± 2.4 (mean ± SD) to 42.8 ± 4.6 % immediately after CEW exposure of eleven pigs (Sus scrofa). Red blood cell count increased significantly from 6.10 ± 0.55 × 10(12)/L to 7.45 ± 0.94 × 10(12)/L, and mean corpuscular volume increased significantly from 54.5 ± 2.4 fl to 57.8 ± 2.6 fl. Mean corpuscular hemoglobin concentration decreased significantly from 20.5 ± 0.7 to 18.5 ± 0.6 mM. Thirty protein spots (from two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis, selected for detailed comparison) exhibited greater densities 30-min post-exposure compared with pre-exposure values. A greater number of echinocytes were observed following CEW exposure. On the basis of these results it appears that, during the strong muscle contractions produced by TASER CEWs, a specific population of red blood cells (RBCs) may be released from the spleen or other reservoirs within the body. The total time of CEW exposure in the present study was relatively long compared with exposures in common law-enforcement scenarios. Despite statistically significant changes in red blood cell counts (and other measures directly related to RBCs), the alterations were short-lived. The transient nature of the changes would be likely to counteract any potentially detrimental effects.

Matrix effects during monitoring of antibody and host cell proteins using attenuated total reflection spectroscopy

Production of recombinant proteins, e.g. antibodies, requires constant real-time monitoring to optimize yield and quality attributes and to respond to changing production conditions, such as host cell protein (HCP) titers. To date, this monitoring of mammalian cell culture-based processes is done using laborious and time consuming enzyme-linked immunosorbent assays (ELISA), two-dimensional sodium dodecylsulphate polyacrylamide gel electrophoresis, and chromatography-based systems. Measurements are usually performed off-line, requiring regular sample withdrawal associated with increased contamination risk. As information is obtained retrospectively, the reaction time to adapt to process changes is too long, leading to lower yield and higher costs. To address the resulting demand for continuous online-monitoring systems, we present a feasibility study using attenuated total reflection spectroscopy (ATR) to monitor mAb and HCP levels of NS0 cell culture in situ, taking matrix effects into account. Fifty-six NS0 cell culture samples were treated with polyelectrolytes for semi-selective protein precipitation. Additionally, part of the samples was subjected to filtration prior to analysis, to change the background matrix and evaluate effects on chemometric quantification models. General models to quantify HCP and mAb in both filtered and unfiltered matrix showed lower prediction accuracy compared to models designed for a specific matrix. HCP quantification in the range of 2,000-55,000 ng mL(-1) using specific models was accurate for most samples, with results within the accepted limit of an ELISA assay. In contrast, mAb prediction was less accurate, predicting mAb in the range of 0.2-1.7 g L(-1) . As some samples deviated substantially from reference values, further investigations elucidating the suitability of ATR for monitoring are required.

Proteomic Analysis of Cellular and Membrane Proteins in Fluconazole-Resistant Candida glabrata

ObjectivesCandida glabrata is one of the most common causes of Candida bloodstream infections worldwide. Some isolates of C glabrata may be intermediately resistant to azoles, with some strains developing resistance during therapy or prophylaxis with fluconazole. In this study, we used a proteomic approach to identify differentially expressed proteins between fluconazole-resistant and -susceptible strains. MethodsMembrane and cellular proteins were extracted from fluconazole-susceptible and fluconazole-resistant C glabrata strains. Differentially expressed proteins were compared using two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. Proteins with >1.5-fold difference in expression were identified by liquid chromatography tandem mass spectrometry (LC-MS/MS). ResultsA total of 65 proteins were differentially expressed in the cellular and membrane fractions. Among the 39 cellular proteins, 11 were upregulated and 28 were downregulated in fluconazole-resistant strains in comparison with fluconazole-susceptible strains. In the membrane fraction, a total of 26 proteins were found, of which 19 were upregulated and seven were downregulated. A total of 31 proteins were identified by LC-MS/MS that are involved in glycolysis, carbohydrate transport, energy transfer, and other metabolic pathways. Heat shock proteins were identified in various spots. ConclusionHeat shock and stress response proteins were upregulated in the membrane fraction of the fluconazole-resistant C glabrata strain. Compared with susceptible strains, fluconazole-resistant strains showed increased expression of membrane proteins and decreased expression of cellular proteins.

P1-01-16: Detecting a Breast Carcinoma-Deriving B-Cell Response: An Immunoproteomics Biomarker Approach.

Abstract Background: Noninvasive biomarkers for the early detection of breast cancer are crucial due to the fact that the relapse risk of breast cancer is rising with the time point of its detection. Currently, none of the reported molecular biomarkers is established for the clinical use as a diagnostic tool. Previous proteomics-based studies showed the immunogenicity of breast carcinoma and the following B-cell mediated immune response. As a result, several autoantibodies against tumor proteins were detected in the sera of breast cancer patients. However, these putative biomarkers are still lacking of clinically reliable specificity and sensitivity, even of better discrimination of cancer patients when combining different biomarkers. The search for a new antibody biomarker signature remains very important as a potential cancer detection tool. For further investigations we analyzed the antibody pattern in serum samples of diseased patients and healthy controls after incubation with whole protein extract from a native carcinoma and identified the putative tumor-specific immunoreactive antigens. Materials and methods: For our de novo profiling of tumor antigens we used a protein extract from a primary invasive ductal carcinoma. Sera from 20 women, of which 19 were diagnosed with breast carcinoma and one with DCIS (CA), and 20 sera from age-matched healthy donors (CTRL) were obtained and pooled separately. For an optimal separation of tumor antigens a two-dimensional sodium dodecylsulfate gel electrophoresis (2D SDS-PAGE) was applied. Following immunoblots with each serum pool were performed and the immunospecific reactions visualized with a horseradish peroxidase-conjugated anti-IgG antibody. The relevant tumor antigens were identified via Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI TOF-TOF MS). Results: After the incubation of each serum pool with tumor antigens we obtained different extensive antibody profiles, whereas the visualized immunoreactive components varied in the signal intensity. We identified over 10 tumor antigens which reacted with the corresponding autoantibodies in CA or CTRL approach, showing again the complexity of immune response. Besides of already described breast carcinoma related antigens like alpha enolase, which showed immune reaction also with the healthy serum pool, we identified several potential antigens of interest like peroxiredoxin 6 which showed a strong immune response only after the incubation with cancer sera. Discussion: In our study we visualized a complex immune response pattern showing the autoantibody profiles in cancer and healthy sera against tumor-deriving antigens. Also some of identified breast carcinoma antigens were already described; other novel breast carcinoma-related antigens were detected too. Our next step in the intriguing search for cancer antibody biomarkers is the individual screening of sera to confirm the specificity of the tumor-deriving B-cell responses and the validation of these results by using an independent study population. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-01-16.

Identification of biochemical differences between the sapwood and transition zone in Robinia pseudoacacia L. by differential display of proteins

Abstract The predominant proteins and enzymes in the sapwood and transition zones of Robinia pseudoacacia L. were identified and expressed by two methods: 2D SDS-PAGE (two-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis) and electrospray ionisation tandem mass spectrometry (ESI-MS/MS). Large differences in the amount of proteins extracted were observed between the bark, sapwood and transition zones. Soluble proteins strongly expressed in sapwood have been identified, and the results interpreted to mean that these proteins are responsible for carbohydrate metabolism and flavonoid turnover. By contrast, proteins strongly expressed in the transition zone are mainly responsible for flavonoid biosynthesis. Lectins were found in protein fractions of both sapwood and the transition zone, and heat-stress proteins were detected only in the transition zone. The results are a further proof that flavonoids are synthesised directly at the transition zone between sapwood and heartwood, and that materials deposited in the sapwood are the source for synthesis of metabolites in heartwood, such as flavonoids and tannins.