Chicken and rabbit antibodies against porcine pepsinogen A.

Isolated porcine pepsinogen A was used for the preparation of polyclonal rabbit and polyclonal chicken anti-pepsinogen A antibodies. Immunochemical properties of both immunoglobulin fractions were compared. The rabbit anti-serum was further purified using immobilized porcine pepsinogen A on magnetic cellulose beads and the resulting anti-pepsinogen A fraction proved to be applicable for the separation and the determination of porcine pepsinogen A. In contrary, antibodies prepared from chicken eggs by the same way have been found not suitable for the evaluation of the pepsinogen A level. Unexpectedly, the pre-immune fraction of chicken antibodies showed reactivity against porcine pepsinogen A and the affinity separation of specific polyclonal chicken anti-pepsinogen A antibodies on immobilized porcine pepsinogen A did not result in an enrichment of anti-pepsinogen A antibodies.

Evaluation of in vitro and in vivo anti-inflammatory activity of biologically active phospholipids with anti-neoplastic potential in porcine model.

BACKGROUND: This study aims to investigate the anti-inflammatory effect of biologically active phospholipids (BAP) used in preparations for clinical practice in humans. Until date, except anti-neoplastic ability, little is known about anti-inflammatory property of the phospholipids. METHODS: While the course of bacterially induced acute pneumonia and markers of inflammation were studied in in vivo system in pigs orally supplemented with BAP, the pro- and anti-inflammatory response of lipopolysaccharide-stimulated porcine monocyte-derived macrophages to 24 h- and 48 h-treatment by BAP was investigated in in vitro system. In vivo, the animal health status was monitored and pro-inflammatory IL-1ß and IL-8 in sera were detected by ELISA during the experiment, while bronchoalveolar lavage fluids (BALF) and the lungs were examined post-mortem. Total and differential counts of white blood cell (WBC) were determined in blood and BALF. In vitro, mRNA expression of pro-inflammatory (TNF-α, IL-1ß, CXCL10) and anti-inflammatory (IL-10 and Arg1) cytokines, and level of activated caspase 1 and phosphorylated protein kinase C epsilon (pPKCϵ), were studied using qRT-PCR and Western blot, respectively. For the purposes of both systems, 6 animals were used in each of the BAP-supplemented and the control groups. RESULTS: In vivo, BAP had a positive influence on the course of the disease. The immunomodulatory effects of BAP were confirmed by lower levels of IL-1ß, IL-8, and a lower WBC count in the supplemented group in comparison with the control group. A lower percentage of lung parenchyma was affected in the supplemented group comparing to the control group (on average, 4% and 34% of tissue, respectively). In vitro, BAP suppressed mRNA expression of mRNA for IL-10 and all pro-inflammatory cytokines tested. This down-regulation was dose- and time-dependent. Arg1 mRNA expression remained unaffected. Further dose- and time-dependent suppression of the activated caspase 1 and pPKCϵ was detected in macrophages when treated with BAP. CONCLUSIONS: Our results demonstrate that BAP has anti-inflammatory and immunomodulatory properties, thus emphasizing the potential of this compound as a natural healing agent.

Monodisperse carboxyl-functionalized poly(ethylene glycol)-coated magnetic poly(glycidyl methacrylate) microspheres: application to the immunocapture of ß-amyloid peptides.

Identification and evaluation of small changes in ß-amyloid peptide (Aß) levels in cerebrospinal fluid is of crucial importance for early detection of Alzheimer's disease. Microfluidic detection methods enable effective preconcentration of Aß using magnetic microparticles coated with Aß antibodies. Poly(glycidyl methacrylate) microspheres are coated with α-amino-ω-methoxy-PEG5000 /α-amino-ω-Boc-NH-PEG5000 Boc groups deprotected and NH2 succinylated to introduce carboxyl groups. Capillary electrophoresis with laser-induced fluorescence detection confirms the efficient capture of Aß 1-40 peptides on the microspheres with immobilized monoclonal anti-Aß 6E10. The capture specificity is confirmed by comparing Aß 1-40 levels on the anti-IgG-immobilized particles used as a control.

Distribution of porcine monocytes in different lymphoid tissues and the lungs during experimental Actinobacillus pleuropneumoniae infection and the role of chemokines.

Monocytes play an essential role in the defense against bacterial pathogens. Bone marrow (BM) and peripheral blood (PB) monocytes in pigs consist of the main "steady-state" subpopulations: CD14 hi/CD163-/SLA-DR- and CD14 low/CD163+/SLA-DR+. During inflammation, the subpopulation of "inflammatory" monocytes expressing very high levels of CD163, but lacking the SLA-DR molecule (being CD14 low/CD163+/SLA-DR-) appears in the BM and PB and replaces the CD14 low/CD163+/SLA-DR+ subpopulation. However, current knowledge of monocyte migration into inflamed tissues in pigs is limited. The aim of the present study was to evaluate the distribution of "inflammatory" CD14 low/CD163+/SLA-DR- monocytes during experimental inflammation induced by Actinobacillus pleuropneumoniae (APP) and a possible role for chemokines in attracting "inflammatory" CD14 low/CD163+/SLA-DR- monocytes into the tissues. Monocyte subpopulations were detected by flow cytometry. Chemokines and chemokine receptors were detected by RT-qPCR. The "steady-state" monocytes were found in the BM, PB, spleen and lungs of control pigs. After APP-infection, "inflammatory" monocytes replaced the "steady-state" subpopulation in BM, PB, spleen and moreover, they appeared in an unaffected area, demarcation zone and necrotic area of the lungs and in tracheobronchial lymph nodes. They did not appear in mesenteric lymph nodes. Levels of mRNA for various chemokines with their appropriate receptors were found to be elevated in BM (CCL3-CCR1/CCR5, CCL8-CCR2/CCR5, CCL19-CCR7), necrotic area of the lungs (CCL3-CCR1, CCL5-CCR1/CCR3, CCL11-CCR3, CCL22/CCR4) and tracheobronchial lymph nodes (CCL3-CCR1) and therefore they could play a role in attracting monocytes into inflamed tissues. In conclusion, "inflammatory" monocytes appear in different lymphoid tissues and the lungs after APP infection in pigs. Various chemokines could drive this process.

Immobilized endoproteinase Glu-C to magnetic bead cellulose as a tool in proteomic analysis.

Magnetic bead cellulose activated with divinyl sulfone was used for the immobilization of Staphylococcus aureus endoproteinase Glu-C (EC 3.4.21.19). The immobilized proteinase was characterized by increased thermostability, by decreased self-cleavage activity, and a possibility of repeated use. The prepared immobilized enzyme was applied for the proteolytic cleavage of α-casein and BSA under different conditions (different composition of buffers, different pH, and different time of digestion). The possibilities of the direct use of enzyme reaction products for MALDI TOF MS analysis were shown.

PEG-modified macroporous poly(glycidyl methacrylate) and poly(2-hydroxyethyl methacrylate) microspheres to reduce non-specific protein adsorption.

To minimize non-specific protein adsorption on macroporous poly(glycidyl methacrylate) and poly(2-hydroxyethyl methacrylate) microspheres containing amino and/or carboxyl groups, the microspheres are coated with α,ω-bis-carboxy poly(ethylene glycol) and amino-terminated poly(ethylene glycol-co-propylene glycol) or α-methoxy-ω-amino poly(ethylene glycol). Adsorption of bovine serum albumin (BSA), γ-globulin, (125) I-BSA, pepsin, and chymotrypsin on neat and PEGylated microspheres is determined by UV-VIS spectroscopy of supernatants and eluates or by measurement of radioactivity in an ionization chamber. Neat and PEGylated microspheres adsorb 0.8-70% and 0.02-44% of protein, respectively.

Application of heptapeptides containing D-amino acid residues immobilized to magnetic particles and Sepharose for the study of binding properties of gastric aspartic proteases.

Synthetic heptapeptides containing D-amino acid residues and differing in the content of L-phenylalanine and L-tyrosine residues and their position (Val-D-Leu-Pro-Tyr-Phe-Val-D-Leu, Val-D-Leu-Pro-Tyr-Tyr-Val-D-Leu, Val-D-Leu-Pro-Phe-Tyr-Val-D-Leu) were immobilized to two types of carriers: glyoxal-activated magnetic agarose particles and CNBr-activated Sepharose. In both cases, peptides were immobilized via their terminal amino group. Immobilized peptides were used for the study of binding properties of two gastric aspartic proteases (porcine pepsin A and rat pepsin C). Porcine pepsin A was adsorbed to all studied peptide-modified magnetic carriers, while rat pepsin C interacted with immobilized ligands only slightly. Similar results were obtained in affinity chromatographic experiments using heptapeptides immobilized to Sepharose.

Magnetic bead cellulose as a suitable support for immobilization of α-chymotrypsin.

Magnetic bead cellulose was prepared by a suspension method from the mixture of viscose and magnetite using thermal sol-gel transition and regeneration of cellulose. The prepared magnetic particles after their activation with divinyl sulfone were shown to be suitable magnetic carrier for immobilization of α-chymotrypsin and for its application in proteomic studies. The specific activity of the immobilized proteinase was high; its activity did not change in the course of storage. The following properties of the immobilized proteinase were compared with those of the soluble enzyme: pH and temperature dependence of the activity, self-cleavage activity, and possibility of repeated use. α-Chymotrypsin immobilized to magnetic bead cellulose was used for the proteolytic digestion of porcine pepsin A and human gastric juice and a possibility of direct use of enzyme reaction products for matrix-assisted laser desorption/ionization time of flight mass spectrometry analysis was shown.

Retention times and bandwidths in reversed-phase gradient liquid chromatography of peptides and proteins.

Due to dramatic effects of even small changes in mobile phase composition on the retention, separations of high-molecular compounds are very difficult, if possible at all, at isocratic conditions and need gradient elution. The theory of gradient elution for small molecules is well established, however its applications to reversed-phase gradient separations of biopolymers are not straightforward because of specific problems, such as slow diffusion, limited accessibility of the stationary phase for larger molecules, or possible sample conformation changes during the elution. Theoretical prediction of gradient data needs the parameters of model retention equations to be known, which however cannot be determined at isocratic conditions. The present work overviews the attempts at implementation of the conventional gradient theory developed for low-molecular compounds to the description and prediction of gradient separations of peptides and proteins on various types of HPLC columns: conventional analytical columns packed with wide-pore fully porous, fused-core superficially porous and non-porous particles; silica-based monolithic columns and organic-polymer poly(alkylmethacrylate) and poly(styrene-divinylbenzene) monolithic columns in capillary and disc formats. The attention is focused on the determination of the parameters necessary to predict gradient retention times (volumes) and bandwidths using the theoretical model equations. The accuracy of the prediction of protein retention on totally porous columns improves if size exclusion effect is taken into account, but this is not necessary with non-porous or superficially porous particles. Band dispersion effects counteracting band compression in gradient elution depend on the type of column, on the protein and on the gradient volume (steepness) and complicate the prediction of band broadening in gradient chromatography of proteins, however the conventional gradient model can be employed to estimate the effects of changing gradient parameters on the bandwidths, as well as on the elution times (volumes) of proteins.

Phosphoprotein electrophoresis in the presence of Fe(III) ions.

Preparation of affinity polyacrylamide gels containing immobilized Fe(III) ions for the separation of proteins exhibiting metal ion binding properties is described. The presented method enables uniform distribution of immobilized metal ions in the affinity part of the polyacrylamide separating gel. Affinity gels prepared by this way are suitable to follow the effect of different concentrations of metal ions immobilized in polyacrylamide gel on a protein electrophoretic behavior. Polyacrylamide gels containing immobilized Fe(III) ions were used to study the electrophoretic behavior of two model proteins differing in their phosphate group content: chicken ovalbumin and bovine α-casein. For the electrophoretic separation, both the native and the denaturating conditions were used.

Host response in rabbits to infection with Pasteurella multocida serogroup F strains originating from fowl cholera.

Although Pasteurella multocida serogroup F has been described as an avian-adapted serogroup, it was recently found in rabbit nests in the Czech Republic. Therefore, the ability of 2 avian P. multocida serogroup F strains to induce disease in rabbits was investigated. Two groups of 18 Pasteurella-free rabbits were intranasally challenged with strains isolated from chickens and turkeys. Half of the animals in each challenge group were immunosuppressed using dexamethasone. All of the challenged rabbits exhibited clinical signs of peracute septicemic disease, ending with shock, and died or were euthanized in the terminal stages of the disease 1 to 2 d post-infection. Gross pathological changes included systemic vascular collapse and vascular leak syndrome. Hyperemia, hemorrhage, edema, inflammatory cell infiltrates, focal necrosis, and degenerative changes were observed histologically in parenchymatous organs. This is the first study directly demonstrating that avian P. multocida serogroup F strains are highly virulent in rabbits and that avian hosts cannot be excluded as a possible source of rabbit infection with serogroup F.

Iminodiacetic acid-modified magnetic poly(2-hydroxyethyl methacrylate)-based microspheres for phosphopeptide enrichment.

Magnetic non-porous hydrophilic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) microspheres prepared by the dispersion polymerization and modified with iminodiacetic acid (IDA) were employed for the IMAC separation of phosphopeptides. Fe(3+) and Ga(3+) ions immobilized on IDA-modified magnetic microspheres were used for the enrichment of phosphopeptides from the proteolytic digests of two model proteins differing in their physico-chemical properties and phosphate group content: porcine pepsin A and bovine α-casein. The optimum conditions for phosphopeptide adsorption and desorption in both cases were investigated and compared. The phosphopeptides separated from the proteolytic digests were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The ability of the prepared Fe(3+)- and Ga(3+)-IDA-modified magnetic microspheres to capture phosphopeptides from complex mixtures was shown on an example of bovine milk proteolytic digest.

Porcine mononuclear phagocyte subpopulations in the lung, blood and bone marrow: dynamics during inflammation induced by Actinobacillus pleuropneumoniae.

Mononuclear phagocytes (MP) are cells of nonspecific immunity, playing an essential role in defense against bacterial pathogens. Although various MP subpopulations have been described in the pig, relations among these populations in vivo are unknown to date. The present study was aimed at describing porcine MP subpopulations infiltrating inflamed tissue of pigs under in vivo conditions. Actinobacillus pleuropneumoniae (APP) infection was used to induce an inflammatory response. CD172alpha, CD14, CD163, MHCII and CD203alpha cell surface molecules were used to identify MP by flow cytometry. Changes in MP subpopulations in the peripheral blood (PB) and bone marrow (BM) compartments along with the analysis of MP appearing in the inflamed lungs were assessed to elucidate the possible origin and maturation stages of the infiltrating MP. The MP population migrating to the inflamed lungs was phenotype CD14+ CD163+ CD203alpha+/- MHCII+/-. Concomitantly, after APP infection there was an increase in the PB MP CD14+ CD163+ CD203alpha- MHC II- population, suggesting that these cells give rise to inflammatory monocytes/macrophages. The CD203alpha and MHCII molecules appear on these cells after leaving the PB. In healthy animals, the BM MP precursors were represented by CD14- CD163- cells maturing directly into CD14+ CD163- that were then released into the PB. After infection, an altered maturation pathway of MP precursors appeared, represented by CD14- CD163- CD203alpha- MHCII- MP directly switching into CD14+ CD163+ CD203alpha- MHCII- MP. In conclusion, two different MP maturation pathways were suggested in pigs. The use of these pathways differs under inflammatory and noninflammatory conditions.

Peptide inhibitor modified magnetic particles for pepsin separation.

Synthetic heptapeptide containing D-amino acid residues (Val-D-Leu-Pro-Phe-Phe-Val-D-Leu) was coupled to glyoxal-activated magnetic agarose particles via the free peptide amino group. The peptide-modified magnetic particles were used for the separation of pepsins. Porcine pepsin A and human pepsin A were adsorbed to the magnetic peptide-modified affinity carrier, while the rat pepsin C and human pepsin C did not interact with the immobilized ligand. Conditions of pepsin adsorption to peptide-modified magnetic particles, as well as elution buffers were optimized. Porcine pepsin A did not interact with the immobilized peptide in the presence of pepsin inhibitor pepstatin A, indicating that the enzyme binding site is involved in the studied interaction. The elaborated method represents a rapid and simple technique not only for the separation of pepsins but also, in combination with MS, for the enzyme detection and determination.

EOF in monolithic poly(styrene-co-divinylbenzene) capillary columns.

In this paper, we present the result of our study on generation of EOF on uncharged poly(styrene-co-divinylbenzene)-based monolithic capillary columns. Three types of neutral monoliths were used: unmodified poly(styrene-co-divinylbenzene) and two modified with octadecyl chains: using grafting process or Friedel-Crafts reaction. The electroosmotic mobilities (mu(EOF)) versus pH profiles are compared, as well as molecular modeling using HyperChem software was employed to describe the observed phenomena. The mu(EOF) was almost independent of pH when pH was increased from 2.5 to 9.5 during the consecutive experiments; however, it decreased significantly when pH was decreasing between these values. The modeling has shown that the buffer molecules can be attracted by the neutral polystyrene surface only in the presence of water molecules, thus creating a negatively charged layer.

Study of pepsin phosphorylation using immobilized metal affinity chromatography.

The interactions of pepsin with immobilized trivalent metal ions and the participation of the enzyme phosphate group in this process were investigated using high performance immobilized metal affinity chromatography. Two different sorbents were used: the newly prepared one, consisting of Ga(3+ )chelate of (6-amino-1-hydroxyhexane-1,1-diyl) bis(phosphonic acid) covalently bound to a methacrylate support (BP-Ga(3+)), and the commercial one, containing immobilized Fe(3+ )ions (POROS MC20-Fe(3+)). The comparison of the behavior of porcine pepsin A and its partially dephosphorylated form on both sorbents showed that both forms of pepsin were adsorbed under the same conditions. To eliminate the participation of free carboxyl groups in pepsin adsorption, both enzyme forms were modified by amidation or esterification. Native enzyme and its partially dephosphorylated form both with modified carboxyl groups differed in their interaction with immobilized Ga(3+ )and Fe(3+). Phosphorylated pepsin molecules with esterified carboxyl groups were adsorbed on both sorbents while nonphosphorylated ones with esterified carboxyl groups were not adsorbed.

Interaction of pepsin with aromatic amino acids and their derivatives immobilized to Sepharose.

The interaction of porcine pepsin A with immobilized derivatives of aromatic amino acids was investigated. Divinyl sulfone-activated Sepharose was used to immobilize N-acetyl-l-phenylalanine and 3,5-diiodo-l-tyrosine via their free carboxyl groups and l-tyrosine via its amino group. Immobilized l-tyrosine was iodinated after coupling. The optimum conditions for the separation of porcine pepsin A using the prepared affinity carriers were studied and the following parameters were established: enzyme recovery, reproducibility of analyses, capacity and dependence of the elution peak area on the concentration of the loaded enzyme. The ability of the prepared affinity carriers to retain various types of proteins was compared under optimum conditions for porcine pepsin A separation. While immobilized 3,5-diiodo-l-tyrosine and iodinated l-tyrosine-Sepharose adsorbed relatively high amounts of bovine serum albumin and ovalbumin, only negligible amounts of these proteins were adsorbed to immobilized N-acetyl-l-phenylalanine. The behavior of porcine pepsin A was the same as its complex with pepstatin A on the prepared affinity carriers, indicating that the enzyme active site is not involved in the studied interaction.

Experimental study of pathogenicity of Pasteurella multocida serogroup F in rabbits.

The role of Pasteurella multocida serogroup F in inducing disease in rabbits was investigated in this study. Three groups of 12 Pasteurella-free rabbits each were intranasally (i.n.), subcutaneously (s.c.), and perorally (p.o.) challenged, respectively. Six rabbits of each group were immunosuppressed using dexamethasone. Eight rabbits (four of them immunosuppressed) inoculated i.n. showed symptoms of respiratory distress resulting in respiratory failure and died or were euthanized in the terminal stage of the disease 3-6 days post-infection (p.i.). The main pathological findings were fibrinopurulent pleuropneumonia (immunocompetent rabbits) or diffuse haemorrhagic pneumonia (immunosuppressed rabbits). Septicemic syndrome ending with shock occurred in 11 rabbits (6 of them immunosuppressed) inoculated s.c., which died or were euthanized in the terminal stage of the disease 2-3 days p.i. The most significant pathological findings were extensive cutaneous and subcutaneous lesions. All of the p.o. inoculated rabbits survived the challenge showing no clinical signs of the disease and no macroscopic lesions. The observations in this study indicate that in addition to serogroups A and D of P. multocida, serogroup F also can be highly pathogenic for rabbits and therefore might be a cause of considerable economic loss in commercial rabbit production.

Alkylated poly(styrene-divinylbenzene) monolithic columns for mu-HPLC and CEC separation of phenolic acids.

Macroporous poly(styrene-divinylbenzene) monolithic columns were prepared in fused silica capillaries of 100 microm id by in-situ copolymerization of styrene with divinylbenzene in the presence of propan-1-ol and formamide as the porogen system. The monoliths were subsequently alkylated with linear alkyl C-18 groups via Friedel-Crafts reaction to improve the retention and chromatographic resolution of strongly polar phenolic acids. A new thermally initiated grafting procedure was developed in order to shorten the time of the alkylation process. The grafting procedure was optimized with respect to the reaction temperature, time, the grafting reactant concentration, and the solvent used. The type of solvent and the grafting temperature are the most significant factors affecting the hydrodynamic properties, porosity, and efficiency of the columns. While the equivalent particle diameter of the grafted column increased, the capillary-like flow-through pore diameter decreased in comparison to non-alkylated monoliths. The hydrodynamic permeability of the monolith decreased, but the monolithic column still permitted fast micro-HPLC separations.

A study of the effects of column porosity on gradient separations of proteins.

The type of the stationary phase for reversed-phase liquid chromatography significantly affects the sample elution. Hydrodynamic properties, efficiency and gradient elution of proteins were investigated on five commercial C18 columns with wide-pore totally porous particles, with superficially porous layer particles, non-porous particles and a silica-based monolithic bed. The efficiency in the terms of reduced plate height is higher for low-molecular ethylbenzene than for proteins, but depends on the character of the pores in the individual columns tested. The superficially porous Poroshell and the non-porous Micra columns provide the best efficiency for proteins at high mobile phase flow rates, probably because of similar pore architecture in the stationary phase. The Zorbax column with similar pore architecture as the Poroshell active layer, i.e. narrow pore distribution of wider pores shows better efficiency than the packed column with narrow pores and broad pore distribution. The monolithic column shows lower efficiency for proteins at high flow rates, but it performs better than the broad-pore distribution totally porous particulate columns. Different pore architecture affects also the retention and selectivity for proteins on the individual columns. The retention times on all columns can be predicted using the model for reversed-phase gradient elution developed originally for low-molecular compounds. Consideration of the limited pore volume accessible to the biopolymers has negligible effect on the prediction of retention on the columns packed with non-porous or superficially porous particles, but improves the accuracy of the predicted data for the totally porous columns with broad pore distribution.