ovalbumin and titanium-dioxide

Food hypersensitivities are increasing in industrialized countries, and foodborne nanoparticles (NPs) are suspected as co-factors in their aetiology. Food-grade titanium dioxide (fg-TiO

Topics: Animals; Female; Food Additives; Interleukin-10; Mice; Ovalbumin; Pregnancy; Titanium; Transforming Growth Factor beta

Maternal gestational exposures to traffic and urban air pollutant particulates have been linked to increased risk and/or worsening asthma in children; however, mechanisms underlying this vertical transmission are not entirely understood. It was postulated that gestational particle exposure might affect the ability to elicit specialized proresolving mediator (SPM) responses upon allergen encounter in neonates. Lipidomic profiling of 50 SPMs was performed in lungs of neonates born to mice exposed to concentrated urban air particles (CAP), diesel exhaust particles (DEP), or less immunotoxic titanium dioxide particles (TiO2). While asthma-like phenotypes were induced with identical eosinophilia intensity across neonates of all particle-exposed mothers, levels of LXA4, HEPE and HETE isoforms, and HDoHe were only decreased by CAP and DEP only but not by TiO2. However, RvE2 and RvD1 were inhibited by all particles. In contrast, isomers of Maresin1 and Protectin D1 were variably elevated by CAP and DEP, whereas Protectin DX, PGE2, and TxB2 were increased in all groups. Only Protectin D1/DX, MaR1(n-3,DPA), 5(S),15(S)-DiHETE, PGE2, and RvE3 correlated with eosinophilia but the majority of other analytes, elevated or inhibited, showed no marked correlation with inflammation intensity. Evidence indicates that gestational particle exposure leads to both particle-specific and nonspecific effects on the SPM network.

Topics: Allergens; Animals; Animals, Newborn; Asthma; Disease Susceptibility; Eosinophilia; Female; Inflammation Mediators; Inhalation Exposure; Lung; Maternal Exposure; Mice; Mice, Inbred BALB C; Ovalbumin; Particulate Matter; Titanium; Vehicle Emissions

Titanium dioxide nanoparticles (TiO

Topics: Animals; Apoptosis; Asthma; bcl-2-Associated X Protein; Bronchoalveolar Lavage Fluid; Carrier Proteins; Caspase 3; Cell Count; Cell Line; Chemical Phenomena; Cytokines; Disease Models, Animal; Gene Expression Regulation; Humans; Hypersensitivity; Immunoglobulin E; Inflammation; Inflammation Mediators; Lung; MAP Kinase Kinase Kinase 5; Mice; Mucus; Nanoparticles; Ovalbumin; Respiratory Hypersensitivity; RNA, Messenger; Thioredoxins; Titanium; Up-Regulation

Titanium dioxide nanoparticles (TiO. According to the results, the mice receiving OVA alone or OVA plus TiO. Based on the findings of the current study, intranasally or inhalation exposure to high-dose nanosized TiO

Topics: Administration, Intranasal; Animals; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Cytokines; Eosinophils; Female; Inhalation Exposure; Mice; Mice, Inbred BALB C; Nanoparticles; Ovalbumin; Respiratory Function Tests; T-Lymphocytes, Helper-Inducer; Titanium

Annexin A5 (ANXA5) has a potential role in cellular signal transduction, inflammation, and fibrosis. However, the exact role of ANXA5 in asthma remains to be clarified. The aims of the present study were to investigate ANXA5 protein expression in a mouse model of asthma and pollutant exposure and to elucidate the relationships between clinical variables and plasma ANXA5 levels in patients with asthma.. ANXA5 protein levels were lower in lung tissue from OVA + OVA mice than in control mice. Lung ANXA5, connective tissue growth factor (CTGF), and transforming growth factor β1 (TGF-β1) protein levels were higher in OVA + TiO. Our results imply that ANXA5 plays a potential role in asthma pathogenesis and may be a promising marker for exacerbated bronchial asthma and exposure to air pollutants.

Topics: A549 Cells; Aged; Air Pollutants; Animals; Annexin A5; Antigens, Dermatophagoides; Asthma; Biomarkers; Connective Tissue Growth Factor; Dermatophagoides pteronyssinus; Disease Models, Animal; Disease Progression; Female; Forced Expiratory Volume; Humans; Male; Mice; Mice, Inbred BALB C; Middle Aged; Nanoparticles; Ovalbumin; Pulmonary Fibrosis; Titanium; Transforming Growth Factor beta1; Vital Capacity

Titanium dioxide nanoparticles (nTiO2) previously considered to possess relatively low toxicity both in vitro and in vivo, although classified as possibly carcinogenic to humans. Also, their adjuvant potential has been reported to promote allergic sensitization and modulate immune responses. Previously, in OVA induced mouse model of asthma we found high expression of Socs3 and low expression of Stat3 and IL-6. However, a clear understanding regarding the signaling pathways associated with nTiO2 adjuvant effect in mouse model of asthma is lacking. In the present study we investigated the status of Stat3/IL-6 and Socs3 and their relationship with NF-κB, with nTiO2 as an adjuvant in mouse model of asthma. nTiO2 when administered with ovalbumin (OVA) during sensitization phase augmented airway hyper-responsiveness (AHR), biochemical markers of lung damage and a mixed Th2/Th1 dependent immune response. At the same time, we observed significant elevation in the levels of Stat3, Socs3, NF-κB, IL-6 and TNF-α. Furthermore, transient in vivo blocking of NF-κB by NF-κB p65 siRNA, downregulated the expression of Socs3, IL-6 and TNF-α. Our study, thus, shows that nTiO2 exacerbate the inflammatory responses in lungs of pre-sensitized allergic individuals and that these changes are regulated via NF-κB pathway.

Topics: Animals; Asthma; Bronchoalveolar Lavage Fluid; Cytokines; Disease Models, Animal; Gene Knockdown Techniques; Hypersensitivity; Inflammation; Lung; Mice, Inbred BALB C; Models, Biological; Nanoparticles; NF-kappa B; Ovalbumin; Signal Transduction; STAT3 Transcription Factor; Suppressor of Cytokine Signaling 3 Protein; Th1 Cells; Th2 Cells; Titanium; Up-Regulation

Development of a simple method for preparation of stable open tubular (OT) columns for proteins separation by capillary electrochromatography is still challenging. In this work, the titanium oxide (TiO2) nanoparticles coated OT column was successfully prepared for separation of proteins by capillary electrochromatography. The polydopamine (PDA) film was first formed in the inner surface of a fused-silica capillary by the self-polymerization of dopamine under alkaline conditions. Then the TiO2 coating was deposited onto the surface of pre-modified capillary with PDA by a liquid phase deposition process. The plentifully active hydroxyl groups in PDA coating can chelate with Ti(4+) to boost the nucleation and growth of TiO2 film. The as-prepared TiO2 coated OT column was characterized by scanning electron microscopy and measurement of electroosmotic flow. Furthermore, the influence of liquid phase deposition time on the TiO2 coating was investigated. The TiO2 coated OT column was used for successful separation of two variants of β-lactoglobulin and eight glycoisoforms of ovalbumin. The column demonstrated good repeatability and stability. The relative standard deviations of migration times of proteins representing run-to-run, day-to-day, and column-to-column were less than 3.7%. Moreover, the application of the column was verified by successful separation of acidic proteins in egg white.

Topics: Capillary Electrochromatography; Indoles; Lactoglobulins; Nanoparticles; Ovalbumin; Polymers; Titanium

Nanomaterials are increasingly used in many fields, including drug vectors and vaccine formulation. In this study, nano-TiO(2) and magnetic Fe(3)O(4)@TiO(2) were synthesized and their abilities to activate dendritic cells were investigated. The signaling pathway involved in their effects on the cellular functions was also explored. First, nano-TiO(2) and Fe(3)O(4)@TiO(2) were prepared with diameters of 82nm and 63nm, and zeta potentials of 41.5mV and 30.2mV, respectively. The magnetic property of Fe(3)O(4)@TiO(2) was detected to be 12.9emu/g. Both kinds of nanoparticles were proved to have good biocompatibility in vitro. Second, the exposure of nano-TiO2 and Fe(3)O(4)@TiO(2)caused an increased expression of TNF-α, CD86 and CD80, and besides, Fe(3)O(4)@TiO(2)showed a certain up-regulation on MHC-II. The cellular uptake of Ovalbumin on BMDCs could be strongly improved by nano-TiO2 and Fe(3)O(4)@TiO(2)as detected via flow cytometer and confocal observation. Further investigation revealed that nano-TiO(2) and Fe(3)O(4)@TiO(2)significantly increased the NF-κB expression in the nucleus, indicating that the NF-κB signaling pathway was involved in the dendritic cell maturation. Our results suggested that nano-TiO(2) and Fe(3)O(4)@TiO(2)may function as a useful vector to promote vaccine delivery in immune cells, and Fe(3)O(4)@TiO(2)provided a possibility to deliver and track vaccines via its magnetofection.

Topics: Animals; B7-1 Antigen; B7-2 Antigen; Biocompatible Materials; Cell Line; Chemical Phenomena; Dendritic Cells; Female; Ferric Compounds; HEK293 Cells; Humans; Metal Nanoparticles; Mice; Mice, Inbred C57BL; NF-kappa B; Ovalbumin; Phagocytosis; Titanium; Tumor Necrosis Factor-alpha

This study examines the immunological responses in rats following inhalation to titanium dioxide nanoparticles (TiO2 NPs), in naïve rats and in rats with induced allergic airway disease. The responses of two different inbred rat strains were compared: the Dark Aguoti (DA), susceptible to chronic inflammatory disorders, and the Brown Norwegian (BN), susceptible to atopic allergic inflammation. Naïve rats were exposed to an aerosol of TiO2 NPs once daily for 10 days. Another subset of rats was sensitized to the allergen ovalbumin (OVA) in order to induce airway inflammation. These sensitized rats were exposed to TiO2 NPs before and during the allergen challenge. Naïve rats exposed to TiO2 NPs developed an increase of neutrophils and lymphocytes in both rat strains. Airway hyperreactivity and production of inflammatory mediators typical of a T helper 1 type immune response were significantly increased, only in DA rats. Sensitization of the rats induced a prominent OVA-specific-IgE and IgG response in the BN rat while DA rats only showed an increased IgG response. Sensitized rats of both strains developed airway eosinophilia following allergen challenge, which declined upon exposure to TiO2 NPs. The level of neutrophils and lymphocytes increased upon exposure to TiO2 NPs in the airways of DA rats but remained unchanged in the airways of BN rats. In conclusion, the responses to TiO2 NPs were strain-dependent, indicating that genetics play a role in both immune and airway reactivity. DA rats were found to be higher responder compared to BN rats, both when it comes to responses in naïve and sensitized rats. The impact of genetically determined factors influencing the inflammatory reactions pinpoints the complexity of assessing health risks associated with nanoparticle exposures.

Topics: Aerosols; Animals; Bronchial Hyperreactivity; Cytokines; Disease Models, Animal; Genetic Variation; Genotype; Immunoglobulin E; Immunoglobulin G; Inflammation Mediators; Inhalation Exposure; Lung; Male; Metal Nanoparticles; Neutrophils; Ovalbumin; Phenotype; Pneumonia; Pulmonary Eosinophilia; Rats, Inbred BN; Risk Factors; Species Specificity; Th1 Cells; Titanium

Titanium dioxide (TiO2) nanoparticles (NPs) are regarded as relatively non-toxic in concentrations occurring in occupational environments. Nevertheless, it is conceivable that adverse health effects may develop in sensitive populations such as individuals with respiratory diseases.. We investigated whether single or repeated exposure to TiO2 could aggravate inflammatory responses in naïve mice and mice with ovalbumin (OVA)-induced airway inflammation.. Exposure to aerosolized TiO2 was performed during OVA sensitization, before, or during the OVA challenge period. The effects on respiratory physiology, inflammatory cells in bronchoalveolar lavage (BAL) and inflammatory mediators in BAL and serum were assessed 24 h after the last OVA challenge or TiO2 exposure.. A single exposure of TiO2 had a marked effect on responses in peripheral airways and increasing infiltration of neutrophils in airways of naïve animals. Marked aggravation of airway responses was also observed in animals with allergic disease provided that the single dose TiO2 was given before allergen challenge. Repeated exposures to TiO2 during sensitization diminished the OVA-induced airway eosinophilia and airway hyperresponsiveness but concomitant exposure to TiO2 during the OVA challenge period resulted in neutrophilic airway inflammation and a decline in general health condition as indicated by the loss of body weight.. We conclude that inhalation of TiO2 may aggravate respiratory diseases and that the adverse health effects are highly dependent on dose and timing of exposure. Our data imply that inhalation of NPs may increase the risk for individuals with allergic airway disease to develop symptoms of severe asthma.

Topics: Administration, Inhalation; Allergens; Animals; Asthma; Bronchoalveolar Lavage Fluid; Cytokines; Female; Fibrinogen; Immunoglobulin E; Immunoglobulin G; Mice; Mice, Inbred BALB C; Nanoparticles; Ovalbumin; Pneumonia; Respiratory Mechanics; Titanium; Toxicity Tests, Acute

Titanium dioxide nanoparticles (nano-TiO(2)) and ethanol vapors are air contaminants with increasing importance. The presence of a pathological pulmonary condition, such as asthma, may increase lung susceptibility to such contaminants.. This study aimed to investigate if exposure to inhaled ethanol vapors or nano-TiO(2) can modulate the rat pulmonary inflammatory response resulting from an allergic asthmatic reaction.. Brown Norway rats were sensitized (sc) and challenged (15 min inhalation, 14 days later) with chicken egg ovalbumin (OVA). Leukocytes were counted in bronchoalveolar lavages (BAL) performed at 6, 24, 36, 48 and 72 h following the challenge and either after ethanol exposures (3000 ppm, 6 h/day, daily) or at 48 h (peak inflammation) for nano-TiO(2) exposures (9.35 mg/m(3) aerosol for 6 and 42 h after the OVA challenge). For the nano-TiO(2) exposures, plasma and BAL cytokines were measured and lung histological analyzes were performed.. Exposure to ethanol did not significantly affect BAL leukocytes after OVA challenge. Exposure to nano-TiO(2) significantly decreased BAL leukocytes compared to OVA-challenged controls. Plasma and BAL IL-4, IL-6, and INF-γ levels were also decreased in the nano-TiO(2) group.. While ethanol vapors do not modify the pulmonary inflammation in rats during an asthmatic response, a surprising protective effect for agglomerated nano-TiO(2) was observed. A putative mechanistic basis involving a decrease in the Th2 response caused by OVA is proposed.. Allergic pulmonary inflammation is not up-regulated by inhalation of the pollutants ethanol and nano-TiO(2). On the contrary, nano-TiO(2) decreases lung inflammation in asthmatic rats.

Topics: Aerosols; Air Pollutants; Animals; Asthma; Bronchoalveolar Lavage Fluid; Cytokines; Disease Models, Animal; Dose-Response Relationship, Drug; Ethanol; Female; Inhalation Exposure; Lung; Male; Nanoparticles; Ovalbumin; Pneumonia; Rats; Rats, Inbred BN; Titanium; Volatilization

The purpose of this study was to investigate whether photocatalytic TiO(2) nanoparticles have adjuvant effect, when administered in combination with ovalbumin (OVA) in mice. Mice were immunized via intraperitoneal injections of OVA, OVA + TiO(2) or OVA + Al(OH)(3) and challenged with aerosols of OVA. At the end of the study, serum was analysed for content of OVA-specific IgE, IgG1 and IgG2a antibodies, and the bronchoalveolar lavage fluid (BALF) was analysed for content of inflammatory cells and levels of interleukin (IL)-4, IL-5, IL-10 and interferon-gamma. The TiO(2) particles promoted a Th2 dominant immune response with high levels of OVA-specific IgE and IgG1 in serum and influx of eosinophils, neutrophils and lymphocytes in BALF. The TiO(2) particles induced a significantly higher level of OVA-specific IgE than the standard adjuvant Al(OH)(3). However, the two substances were comparable regarding the level of eosinophilic inflammation and interleukins present in BALF.

Topics: Adjuvants, Immunologic; Aluminum Hydroxide; Animals; Bronchoalveolar Lavage Fluid; Female; Immunoglobulin E; Immunoglobulin G; Injections, Intraperitoneal; Interferon-gamma; Interleukins; Lung; Mice; Mice, Inbred BALB C; Nanoparticles; Ovalbumin; Titanium

Nanotechnology and engineered nanomaterials (ENM) are here to stay. Recent evidence suggests that exposure to environmental particulate matter exacerbates symptoms of asthma. In the present study we investigated the modulatory effects of titanium dioxide particle exposure in an experimental allergic asthma.. Nonallergic (healthy) and ovalbumin-sensitized (asthmatic) mice were exposed via inhalation to two different sizes of titanium dioxide particles, nanosized (nTiO2) and fine (fTiO2), for 2 hours a day, three days a week, for four weeks at a concentration of 10 mg/m3. Different endpoints were analysed to evaluate the immunological status of the mice.. Healthy mice elicited pulmonary neutrophilia accompanied by significantly increased chemokine CXCL5 expression when exposed to nTiO2. Surprisingly, allergic pulmonary inflammation was dramatically suppressed in asthmatic mice which were exposed to nTiO2 or fTiO2 particles - i.e. the levels of leucocytes, cytokines, chemokines and antibodies characteristic to allergic asthma were substantially decreased.. Our results suggest that repeated airway exposure to TiO2 particles modulates the airway inflammation depending on the immunological status of the exposed mice.

Topics: Animals; Asthma; Cytokines; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Inhalation Exposure; Leukocytes; Mice; Mice, Inbred BALB C; Nanoparticles; Ovalbumin; Particulate Matter; Pneumonia; Titanium

Previous studies have shown that inhaled particles exacerbate asthma and allergic rhinitis. Several factors related to the particle may play a role in immune-stimulating activity; however, the underlying mechanisms remain unclear. We carried out in vitro studies to investigate the effects of TiO(2) particle exposure on antigen presenting activity and expression of the associated cell-surface molecules (Ia, B7.1, B7.2) in rat derived monocytes and alveolar macrophages, in terms of two aspects of the particles: (1) size (59 nm (ST) and 350 nm (LT) particles), and (2) the timing of particle exposure (before antigen exposure or co-administered). Results indicated that particle exposure prior to antigen exposure led to decreased antigen presenting activity in both types of cell. This decrease was greater with ST particles. In monocytes, the expression of cell surface molecules decreased similarly with both particles. Conversely, alveolar macrophages showed greater expression of Ia with ST than with LT exposures. Ia expression was confirmed to be functionally active by a mixed lymphocyte reaction. It is possible that particle exposure might result in poor antigen processing, thereby leading to decreased antigen presenting activity. Co-exposure of particles and antigen induced an increase in antigen presenting activity with both types of particle; however, ST exposure induced greater antigen presenting activity. The expression of Ia also increased similarly with both particle sizes. This suggests that, in a co-exposure situation, antigen may be processed without intensive retardation by particles, and factors other than Ia may affect antigen presenting activity. In conclusion, both size and timing of exposure to TiO(2) particles affect antigen presenting activity of monocytes and alveolar macrophages.

Topics: Animals; Antigen-Presenting Cells; Antigens, Surface; Antimetabolites; Biocompatible Materials; Bromodeoxyuridine; Flow Cytometry; Indicators and Reagents; Macrophages, Alveolar; Male; Monocytes; Ovalbumin; Particle Size; Rats; T-Lymphocytes; Titanium

Due to the dynamic nature and low stoichiometry of protein phosphorylation, enrichment of phosphorylated peptides from proteolytic mixtures is often necessary prior to their characterization by mass spectrometry. Immobilized metal affinity chromatography (IMAC) is a popular way to enrich phosphopeptides; however, conventional IMAC lacks enough specificity for efficient phosphoproteome analysis. In this study, novel Fe 3O 4@TiO 2 microspheres with well-defined core-shell structure were prepared and developed for highly specific purification of phosphopeptides from complex peptide mixtures. The enrichment conditions were optimized using tryptic digests of beta-casein, and the high specificity of the Fe 3O 4@TiO 2 core-shell microspheres was demonstrated by effectively enriching phosphopeptides from the digest mixture of alpha-casein and beta-casein, as well as a five-protein mixture containing nonphosphoproteins (bovine serum albumin (BSA), myoglobin, cytochrome c) and phosphoproteins (ovalbumin and beta-casein). The Fe 3O 4@TiO 2 core-shell microspheres were further successfully applied for the nano-LC-MS/MS analysis of rat liver phosphoproteome, which resulted in identification of 56 phosphopeptides (65 phosphorylation sites) in mouse liver lysate in a single run, indicating the excellent performance of the Fe 3O 4@TiO 2 core-shell microspheres.

Topics: Amino Acid Sequence; Animals; Caseins; Cytochromes c; Ferric Compounds; Ferrous Compounds; Hydrogen-Ion Concentration; Iron Compounds; Liver; Microspheres; Molecular Sequence Data; Myoglobin; Ovalbumin; Phosphopeptides; Phosphoproteins; Phosphorylation; Proteomics; Rats; Serum Albumin, Bovine; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Tandem Mass Spectrometry; Titanium; Trypsin

Titanium dioxide (TiO2)-mediated phosphopeptide enrichment has been introduced as an effective method for extracting phosphopeptides from highly complex peptide mixtures. Chemical labeling by beta-elimination/Michael addition is also useful for increasing mass intensity in phosphopeptide analysis. Both of these methods were coupled in order to simultaneously enrich phosphopeptides and allow for detection and sequencing of the enriched peptides with high mass sensitivity. Phosphopeptides were successfully enriched on TiO2 beads without the use of any hydroxy acid additives like 2,5-dihydroxybenzoic acid. Labeling was accomplished on-bead with a guanidinoethanethiol (GET) tag containing a guanidine moiety. These GET-labeled derivatives were detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). GET labeling converted phosphoserine into guanidinoethylcysteine, a structural arginine-mimic. In particular, GET-labeled lysine-terminated phosphopeptides showed dramatically increased peak intensities compared to those of the corresponding intact phosphopeptides. Additionally, the on-bead labeling minimized manipulation steps and sample loss. The coupled technique was also further validated by applying to the analysis of phosphopeptides from complex tryptic digests of phosphoprotein mixtures.

Topics: Amino Acid Sequence; Animals; Caseins; Guanidine; Molecular Sequence Data; Ovalbumin; Phosphopeptides; Phosphoproteins; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Sulfhydryl Compounds; Titanium

Airborne particulate matter (PM) is an important factor associated with the enhanced prevalence of respiratory allergy. The PM adjuvant activity on allergic sensitization is a possible mechanism of action involved, and the induction of airway inflammation is suggested to be of importance in PM-induced adjuvant activity.. Because differently sized PM have different toxic potentials, we studied the role of particle size in the induction of airway inflammation and allergic sensitization. This was done using fine (0.250 and 0.260 micro m) and ultrafine (0.029 and 0.014 micro m) titanium dioxide (TiO(2)) and carbon black particles (CBP) with known differences in airway toxicity.. Mice were intranasally exposed to ovalbumin (OVA) alone or in combination with one of the different particles. The induction of airway inflammation and the immune adjuvant activity were studied in the lungs and lung-draining peribronchial lymph nodes (PBLN) at day 8. OVA-specific antibodies were measured at day 21, and the development of allergic airway inflammation was studied after OVA challenges (day 28).. When administered at the same total particle mass (200 micro g), exposure to ultrafine TiO(2) and CBP-induced airway inflammation, and had immune adjuvant activity. The latter was shown by increasing both the PBLN cell numbers and the production of OVA-specific T-helper type 2 (Th2) cytokines (IL-4, IL-5, IL-10 and IL-13). Whereas OVA-specific IgE and IgG1 levels in serum were only increased in animals exposed to the ultrafine TiO(2), allergic airway inflammation could be detected in both ultrafine TiO(2)-and CBP-treated groups after challenges with OVA.. Our data show that only the ultrafine particles, with a small diameter and a large total surface area/mass, cause airway inflammation and have immune adjuvant activity in the current model supporting the hypothesis that particle toxicity is site-dependent and related to adjuvant activity.

Topics: Animals; Antigens; Bronchoalveolar Lavage Fluid; Female; Flow Cytometry; Immunoglobulin E; Immunoglobulin G; Lung; Mice; Mice, Inbred BALB C; Models, Animal; Ovalbumin; Particle Size; Particulate Matter; Respiratory Hypersensitivity; Soot; Titanium

Reversible phosphorylation of proteins regulates the majority of all cellular processes, e.g. proliferation, differentiation, and apoptosis. A fundamental understanding of these biological processes at the molecular level requires characterization of the phosphorylated proteins. Phosphorylation is often substoichiometric, and an enrichment procedure of phosphorylated peptides derived from phosphorylated proteins is a necessary prerequisite for the characterization of such peptides by modern mass spectrometric methods. We report a highly selective enrichment procedure for phosphorylated peptides based on TiO2microcolumns and peptide loading in 2,5-dihydroxybenzoic acid (DHB). The effect of DHB was a very efficient reduction in the binding of nonphosphorylated peptides to TiO2 while retaining its high binding affinity for phosphorylated peptides. Thus, inclusion of DHB dramatically increased the selectivity of the enrichment of phosphorylated peptides by TiO2. We demonstrated that this new procedure was more selective for binding phosphorylated peptides than IMAC using MALDI mass spectrometry. In addition, we showed that LC-ESI-MSMS was biased toward monophosphorylated peptides, whereas MALDI MS was not. Other substituted aromatic carboxylic acids were also capable of specifically reducing binding of nonphosphorylated peptides, whereas phosphoric acid reduced binding of both phosphorylated and nonphosphorylated peptides. A putative mechanism for this intriguing effect is presented.

Topics: Amino Acid Sequence; Animals; Carbonic Anhydrases; Caseins; Cattle; Chickens; Gentisates; Molecular Sequence Data; Ovalbumin; Phosphopeptides; Serum Albumin; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Titanium

Two approaches are suggested for the acceleration of the photocatalytic oxidation of organic contaminants of water: acceleration by oxidants and photo-enhancement by dyes. These processes were examined with several substances: two widely applied herbicides, bromacil (a uracil) and metribuzin (a triazine), and three proteins, studied as models of biocontaminated waters. The effects of oxygen and hydrogen peroxide indicated two different reaction patterns of photo-oxidation of the herbicides. With metribuzin, oxygen had a pronounced effect on the rate of photo-oxidation, while the influence of hydrogen peroxide was quite moderate; with bromacil, oxygen had a limited effect on the rate of photo-oxidation, which however was considerably enhanced by hydrogen peroxide. Acceleration of the photo-catalytic oxidation of colourless refractory contaminants by photo-excited dye was observed. Both UV and visible light were required for the enhanced decomposition. The mechanism of the reaction seems to involve a combination of oxidation by hydroxyl radicals, via the hole-electron semiconductor route, with subsequent oxidation of photo-intermediates by singlet oxygen formed by dye sensitization. The TiO2-photocatalyzed oxidation of proteins (albumin, ovalbumin and gamma-globulin) showed the susceptibility of proteins to photocleavage and of the amino acids to photocatalytic degradation. Tyrosine was the most sensitive, while the degradation of the aliphatic amino acids Gly and Asp was slow.

Topics: Albumins; Biological Products; Bromouracil; Catalysis; Coloring Agents; gamma-Globulins; Hydrogen Peroxide; Light; Methylene Blue; Ovalbumin; Oxidants; Oxidation-Reduction; Oxygen; Pesticides; Proteins; Titanium; Triazines; Ultraviolet Rays; Water; Water Pollutants, Chemical

Diesel exhaust particles (DEP) are reported to increase the specific IgE response to allergens, and results from our laboratory suggest that the particle core of DEP contribute to this adjuvant activity. The purpose of the present study was to explore further the adjuvant effect of particles per se, that is particles by themselves. NIH/Ola mice were given two intraperitoneal injections with ovalbumin (OVA; 10 microg) alone or OVA in combination with PSP, polytetrafluoroethylene (teflon), titanium dioxide (TiO(2)) or amorphous silica particles (2.8x10(10)-2.8x10(12)). Blood samples were drawn 7 days after the last injection, and serum levels of allergen-specific and total IgE and IgG2a were measured. All types of particles gave increased levels of allergen-specific IgE and IgG2a. Similar results were obtained after intranasal or intratracheal instillation with OVA plus PSP or silica. Our results indicate that fine particles of widely different composition may have an adjuvant effect on the production of allergen-specific antibodies.

Topics: Adjuvants, Immunologic; Allergens; Animals; Antibody Specificity; Chickens; Female; Immunoglobulin E; Immunoglobulin G; Mice; Mice, Inbred Strains; Octoxynol; Ovalbumin; Particle Size; Polystyrenes; Polytetrafluoroethylene; Silicon Dioxide; Surface-Active Agents; Titanium

The TiO2 photocatalyzed oxidation of the proteins serum albumin, ovalbumin and gamma globulin, is reported. All the amino acids were susceptible to photocatalytic oxidation. However, some were especially vulnerable. Tyrosine was particularly sensitive, as was the semiaromatic histidine, although to a lesser extent. The lack of an activating group on the aromatic ring in Phe, renders the system less amenable to degradation. The photocatalytic degradation of the aliphatic amino acids Gly and Asp, was particularly slow, like in the Fenton oxidation where production of glycine was observed during the cleavage of collagen induced by hydroxyl radicals. Intermediate degradation rate was noticed in Ser, Arg, Val, Cys and Phe.

Topics: Amino Acids; Catalysis; gamma-Globulins; Kinetics; Ovalbumin; Oxidation-Reduction; Photosensitizing Agents; Serum Albumin, Bovine; Titanium; Water Pollutants, Chemical