Immobilization of heparin on polyacrylamide derivatives

Heparinization of Beta Tricalcium Phosphate: Osteo-immunomodulatory Effects

Immune cells play a vital role in regulating bone dynamics. This has boosted the interest in developing biomaterials that can modulate both the immune and skeletal systems. In this study, calcium phosphates discs (i.e., beta-tricalcium phosphate, β-TCP) are functionalized with heparin to investigate the effects on immune and stem cell responses. The results show that the functionalized surfaces downregulate the release of hydrogen peroxide and proinflammatory cytokines (tumor necrosis factor alpha and interleukin 1 beta) from human monocytes and neutrophils, compared to nonfunctionalized discs. The macrophages show both elongated and round shapes on the two ceramic substrates, but the morphology of cells on heparinized β-TCP tends toward a higher elongation after 72 h. The heparinized substrates support rat mesenchymal stem cell (MSC) adhesion and proliferation, and anticipate the differentiation toward the osteoblastic lineage as compared to β-TCP and control. The coupling between the inflammatory response and osteogenesis is assessed by culturing MSCs with the macrophage supernatants. The downregulation of inflammation in contact with the heparinized substrates induces higher expression of bone-related markers by MSCs.

Origin, localization and binding abilities of boar DQH sperm surface protein tested by specific monoclonal antibodies

Seminal plasma proteins bind the sperm surface at ejaculation and may modulate several aspects of sperm activity during reproduction. DQH sperm surface protein, present in boar seminal plasma, shows affinity to phoshorylcholine, acidic polysaccharides, oviductal epithelium and zona pellucida glycoproteins. Monoclonal antibodies (MAbs) against DQH protein were prepared and used for determination of the DQH protein origin in boar reproductive organs, its localization on boar spermatozoa, and for investigation of its binding abilities in the porcine oviduct and to the zona pellucida of the oocyte. The mRNA transcript of DQH protein was found in seminal vesicles and not in the testis, epididymis and prostate. Its translated products were immunodetected by MAbs in seminal vesicle extract and fluid, in seminal vesicle tissue sections and on the membrane-associated acrosomal part of ejaculated spermatozoa. These results confirm the ability of DQH protein to bind the sperm surface at ejaculation and to participate in formation of the sperm reservoir in the porcine oviduct. Moreover, monoclonal antibodies reduced binding of sperm to oocytes and proved the role of DQH protein in the sperm-zona pellucida primary binding.

Separation, characterization and identification of boar seminal plasma proteins

Methods used for the isolation, separation and characterization of boar seminal plasma proteins are discussed, as well as techniques applied to study their binding properties. Attention is paid to interactions of these proteins with different types of saccharides and glycoconjugates, with membrane phospholipids, and to interactions between proteins. Boar seminal plasma contains different types of proteins: spermadhesins of the AQN and AWN families; DQH and PSP proteins belong to the most abundant. Some of these proteins are bound to the sperm surface during ejaculation and thus protein-coating layers of sperm are formed. Sperms coated with proteins participate in different types of interactions occurring in the course of the reproduction process, e.g. formation of the oviductal sperm reservoir, sperm capacitation, oocyte recognition and sperm binding to the oocyte.

Saccharide-mediated interactions of boar sperm surface proteins with components of the porcine oviduct

The role of boar seminal plasma proteins attached to the sperm plasma membrane during ejaculation has been studied in saccharide-mediated events in the female reproductive tract. Heparin-binding (Hep(+)) proteins (DQH sperm surface protein, and AQN and AWN spermadhesins) and their aggregated forms (fractions II and III) interacted more strongly with both oviductal epithelium cells and fluid than non-heparin-binding (Hep(-)) proteins (PSP I and PSP II spermadhesins) and their heterodimer (fraction IV), and interactions correlate with affinity of these proteins to yeast mannan. Indirect immunofluorescence (IMF) showed that the AQN 1 spermadhesin and fraction II bind to the apical glycocalyx of the ampulla, as well as the isthmic and uterine tubal junction regions of the oviductal sections. IMF demonstrated the recognition of AQN 1 and fraction II and mannosyl components of oviductal epithelium. We suggest that Hep(+) proteins (especially AQN 1, fraction II) on sperm could enable sperm binding to oviductal epithelium and thus participate in formation of the sperm oviductal reservoir. Interactions of Hep(+) proteins to oviductal epithelium were inhibited by mannan, hyaluronic acid and sialylated O-glycoproteins. No or slight inhibition was observed with sulphated polysaccharides (heparin, chondroitin sulphate) and simple monosaccharides. Besides that, attachment of boar seminal plasma proteins to oviductal epithelium cells was affected by oviductal fluid, the natural environment in the oviduct. Moreover, the ability of hyaluronic acid to inhibit the interaction of sperm surface proteins to the oviduct might play a role in sperm release from the oviductal reservoir and in the capacitation process.

Affinity liquid chromatography and capillary electrophoresis of seminal plasma proteins

Interactions of boar, bull, and human seminal plasma proteins with heparin and phosphorylcholine were studied by affinity LC using heparin immobilized to a Toyopearl support. A step gradient elution from 0.15 to 1.50 M NaCl was employed to elute the seminal plasma proteins. Relative amounts of the heparin-binding fraction of seminal plasma proteins (H+) in seminal plasma of three species were determined. Further on, the fraction of seminal plasma proteins interacting with phosphorylcholine-binding proteins (P+) was evaluated. P+ proteins were not found in human seminal plasma and their highest amount was present in bull seminal plasma. A CE method was developed for separation of seminal plasma proteins. Various capillaries and separation conditions were tested; the best resolution was obtained in a bare-silica capillary, with a micellar system consisting of a 0.02 M borate buffer and 0.05 M SDS pH 10.0. The optimized conditions were applied to the identification of the components in boar plasma.

Mannan-binding proteins from boar seminal plasma

The interaction of boar seminal plasma proteins and sperm with yeast mannan was investigated by the enzyme-linked binding assay (ELBA) and specific detection of proteins after SDS electrophoresis and blotting using biotinylated derivative of the polysaccharide. Heparin-binding proteins (especially AQN 1 and DQH proteins) and their aggregated forms showed affinity to yeast mannan. Besides that, these proteins were shown to bind to oviductal epithelium. The mannan-binding activity of boar proteins and sperm was inhibited most efficiently by ovomucoid, ovalbumin and N-glycans released from ovalbumin, but not with d-glucose, d-mannose and their phosphates. On the other hand, yeast mannan inhibited both the interaction of boar seminal plasma and sperm with heparin and the binding of these proteins to porcine oviductal epithelium. Yeast mannan immobilized to divinyl sulfone-activated Sepharose was used for the isolation of mannan-binding proteins. Proteins adsorbed to the immobilized polysaccharide were analyzed by RP-HPLC, SDS electrophoresis and N-terminal amino acid sequencing. AQN and AWN spermadhesins and DQH protein (names are derived from the N-terminal amino acid sequence) were identified as components of the isolated fraction. The results suggest an involvement of mannan-binding proteins in the formation of the sperm oviductal reservoir in pig. The ability of these proteins to interact both the complex d-mannose-containing saccharide structures and the heparin may also play an important role in sperm release from the oviductal reservoir or the capacitation process.

Aggregated Forms of Bull Seminal Plasma Proteins and Their Heparin-Binding Activity

Heparin-binding activity of bull seminal plasma proteins was shown to be dependent on their aggregation state. The protein fraction interacting with immobilized heparin was characterized by large polydispersity in the region of molecular weight of 60 000-10 000, while that not retained on the affinity carrier was present as aggregates with molecular weight >100 000. Components of heparin-binding and non-heparin-binding fractions were separated by RP HPLC (reversed-phase HPLC) and analyzed by SDS (sodium dodecyl sulfate) electrophoresis and N-terminal sequencing. Size exclusion chromatography of whole seminal plasma and heparin-binding proteins in the presence of D-fructose (as a component of seminal plasma) showed that the region of molecular weights of protein-associated forms was shifted to lower values. An increase of heparin-binding activity of bull proteins, as determined by ELBA (Enzyme-Linked Binding Assay), correlates with a decrease of their aggregation state. The modulation of the aggregation state of bull proteins by seminal plasma components and, in this way, also of their heparin-binding properties suggests possible mechanisms for capacitation mediated by these proteins.

Boar Seminal Plasma Proteins and Their Binding Properties. A Review

Binding properties of a group of proteins isolated from boar seminal plasma and their role in the fertilization process are discussed. Boar seminal plasma contains different types of proteins: spermadhesins of AQN and AWN family, DQH and PSP proteins belong to the most abundant. Some of these proteins are bound to the sperm surface during ejaculation and thus protein-coating layers are formed. Sperms coated with proteins participate in different types of interactions in the following steps of the fertilization process: formation of oviductal sperm reservoir, sperm capacitation, oocyte recognition and sperm binding. Saccharide-based interactions of boar seminal plasma proteins play role in the binding of sperm to oviductal epithelium, in sperm capacitation and primary binding of sperm to zona pellucida. An interaction with phospholipid components is responsible for the protein adsorption to sperm membrane. Interactions between proteins participate in the arrangement and remodelling of sperm-coating layers. Study of boar seminal plasma proteins, their characterization and elucidation of their interactions will contribute to understanding the fertilization process. A review with 82 references.

Mutual Interactions of Boar Seminal Plasma Proteins Studied by Immunological and Chromatographic Methods

PROBLEM

Boar seminal plasma contains various types of proteins. Most of them belong to spermadhesins and some of them contain fibronectin type II domain. Almost all of these proteins are present under physiological conditions in aggregated forms differing in their relative molecular mass, composition, and binding properties. The study of mutual specific interactions between proteins of boar seminal plasma that could be involved in the formation of aggregated forms and most probably of sperm coating layers is the subject of our present communication.

METHODS OF STUDY

Aggregated forms of boar seminal plasma proteins separated by size exclusion chromatography were analysed by Reversed-phase High-performance Liquid Chromatography (RP HPLC), SDS-PAGE and immunochemical methods (ELISA and immunoblotting). Mutual interactions between proteins were investigated by size exclusion chromatography of a mixture of separated monomer proteins and affinity chromatography of boar seminal plasma on immobilized spermadhesins.

RESULTS

Composition of proteins that are adsorbed from boar seminal plasma to immobilized spermadhesins corresponds to that of aggregated forms found in seminal plasma. Mutual interactions between monomer forms observed by size exclusion chromatography are in good agreement with results of affinity chromatography. An existence of interactions between spermadhesins of the AQN and AWN families and the DQH sperm surface protein, as well as between proteins involved in the formation of heterodimer porcine seminal plasma I (PSP I)/PSP II was proved.

CONCLUSION

Mutual specific interactions between protein components of boar seminal plasma were shown. These interactions participate in the formation of aggregated forms of proteins in seminal plasma and probably also in the arrangement and remodelling of protein coating layers of sperm. Aggregation of seminal plasma proteins is probably an important phenomenon in the fertilization process.

Affinity chromatography of bull seminal proteins on mannan-Sepharose

The interaction of bull seminal plasma proteins and sperm with mannan was investigated using an enzyme-linked binding assay (ELBA). A high mannan-binding activity was found in the protein fraction interacting with heparin. Mannan binding to seminal plasma proteins was inhibited by D-mannose and D-fructose, but not by D-mannose-6-phosphate, D-glucose-6-phosphate, ovalbumin and ovomucoid. Mannan inhibited the binding of bovine zona pellucida glycoproteins both to bull sperm and seminal plasma proteins. Yeast mannan immobilized to divinyl sulfone-activated Sepharose was used for the isolation of mannan-binding proteins. The protein components of this fraction were identified on the basis of relative molecular mass determination and N-terminal amino acid sequencing: RNAase dimer, PDC-109 and a protein homologous to BSP-30K (relative molecular mass 14,500). The isolated proteins were characterized by a high zona pellucida binding activity.

Characterization of proteins from boar prostate

PROBLEM

Most components of seminal plasma are secreted by accessory sexual glands: seminal vesicle, prostate gland and bulbourethral gland. The portion of proteins secreted by prostate gland differs in various species. Characterization of boar prostate proteins is the subject of this communication.

METHODS OF STUDY

Proteins of boar prostate gland were separated by affinity chromatography on heparin-polyacrylamide to non-heparin-binding (H-) and heparin-binding (H+) fractions. The H- and H+ fractions were subjected to reverse phase high performance liquid chromatography (RP HPLC) and their elution profiles were compared with those of the H- and H+ fractions of boar seminal plasma. The isolated proteins were characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), immunodetection, N-terminal amino acid sequencing and mass spectrometry (MALDI).

RESULTS

The following proteins of boar prostate secretion were identified: beta-microseminoprotein, serotransferrin, serum albumin, myoglobin and PSP I and PSP II spermadhesins.

CONCLUSION

Presented results demonstrate composition of the main proteins of boar prostate secretion. Beta-Microseminoprotein was found to be a major protein of prostate secretion. PSP I and PSP II, major proteins of the H- fraction of boar seminal plasma, were found in boar prostate secretion in lower amounts. The major proteins of the H+ fraction of boar seminal plasma (AQN, AWN) were not detected in prostate secretion.

Immobilization of L-glyceryl phosphorylcholine: isolation of phosphorylcholine-binding proteins from seminal plasma

The preparation of an affinity sorbent containing immobilized L-glyceryl phosphorylcholine for affinity chromatography of phosphorylcholine-binding proteins from seminal plasma is described. The ligand was coupled either after its maleinylation to poly(acrylamide-allyl amine) copolymer or directly to divinyl sulfone-activated Sepharose. The prepared phosphorylcholine derivative coupled to Sepharose was used for affinity chromatography of phosphorylcholine-binding proteins from bull and boar seminal plasma. Adsorbed proteins were specifically eluted with phosphorylcholine solution. Isolated phosphorylcholine-binding proteins were characterized by SDS electrophoresis and HPLC with reversed phase. Composition of the boar phosphorylcholine-binding fraction obtained by affinity chromatography on immobilized L-glyceryl phosphorylcholine was compared with that eluted from immobilized heparin by the phosphorylcholine solution. No phosphorylcholine-binding proteins were found in human seminal plasma.

Isolation of non-heparin-binding and heparin-binding proteins of boar prostate

Proteins of boar prostate secretion were separated by affinity chromatography on heparin-polyacrylamide to non-heparin-binding (H) and heparin-binding (H+) protein fractions. H- and H+ fractions were then subjected to RP HPLC. Elution profiles of H-and H+ fractions of prostate secretion were compared with those of seminal plasma and the amounts of corresponding proteins were compared. Besides, the isolated proteins were characterized by SDS-PAGE. In the H- fraction of prostate secretion, PSP I and PSP II spermadhesins and in the H+ fraction AQN 2 and AWN 1 spermadhesins were found in substantially lower amounts than in seminal plasma. On the contrary, beta-microseminoprotein was identified in abundant amounts both in H- and H+ fractions of boar prostate secretion. AQN 2 and AWN 1 spermadhesins were proved by their antibodies. Some seminal plasma proteins originating mainly in seminal vesicles could also be secreted by the prostatic gland. beta-Microseminoprotein was found to be produced mainly by the prostate.

Chemical modification of titanium surfaces for covalent attachment of biological molecules

The surface of implantable biomaterials is in direct contact with the host tissue and plays a critical role in determining biocompatibility. In order to improve the integration of implants, it is desirable to control interfacial reactions such that nonspecific adsorption of proteins is minimized and tissue-healing phenomena can be controlled. In this regard, our goal has been do develop a method to functionalize oxidized titanium surfaces by the covalent immobilization of bioactive organic molecules. Titanium first was chemically treated with a mixture of sulfuric acid and hydrogen peroxide to eliminate surface contaminants and to produce a consistent and reproducible titanium oxide surface layer. An intermediary aminoalkylsilane spacer molecule was then covalently linked to the oxide layer, followed by the covalent binding of either alkaline phosphatase or albumin to the free terminal NH2 groups using glutaraldehyde as a coupling agent. Surface analyses following coating procedures consisted of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Enzymatic activity of coupled alkaline phosphatase was assayed colorimetrically, and surface coverage by bound albumin was evaluated by SEM visualization of colloidal gold immunolabeling. Our results indicate that the linkage of the aminoalkylsilane to the oxidized surface is stable and that bound proteins such alkaline phosphatase and albumin retain their enzymatic activity and antigenicity, respectively. The density of immunolabeling for albumin suggests that the binding and surface coverage obtained is in excess of what would be expected for inducing biological activity. In conclusion, this method offers the possibility of covalently linking selected molecules with known biological activity to oxidized titanium surfaces in order to guide and promote the tissue healing that occurs during implant integration in bone and soft tissues.

Chemical modification of titanium surfaces for covalent attachment of biological molecules

The surface of implantable biomaterials is in direct contact with the host tissue and plays a critical role in determining biocompatibility. In order to improve the integration of implants, it is desirable to control interfacial reactions such that nonspecific adsorption of proteins is minimized and tissue-healing phenomena can be controlled. In this regard, our goal has been do develop a method to functionalize oxidized titanium surfaces by the covalent immobilization of bioactive organic molecules. Titanium first was chemically treated with a mixture of sulfuric acid and hydrogen peroxide to eliminate surface contaminants and to produce a consistent and reproducible titanium oxide surface layer. An intermediary aminoalkylsilane spacer molecule was then covalently linked to the oxide layer, followed by the covalent binding of either alkaline phosphatase or albumin to the free terminal NH2 groups using glutaraldehyde as a coupling agent. Surface analyses following coating procedures consisted of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Enzymatic activity of coupled alkaline phosphatase was assayed colorimetrically, and surface coverage by bound albumin was evaluated by SEM visualization of colloidal gold immunolabeling. Our results indicate that the linkage of the aminoalkylsilane to the oxidized surface is stable and that bound proteins such alkaline phosphatase and albumin retain their enzymatic activity and antigenicity, respectively. The density of immunolabeling for albumin suggests that the binding and surface coverage obtained is in excess of what would be expected for inducing biological activity. In conclusion, this method offers the possibility of covalently linking selected molecules with known biological activity to oxidized titanium surfaces in order to guide and promote the tissue healing that occurs during implant integration in bone and soft tissues.

A novel method for glycoconjugate synthesis

2-Chloroethyl 1-thio-beta-D-galactopyranoside and the corresponding 1-thio-beta-D-glucopyranoside have been found to be suitable glycosylating agents for the preparation of different types of glycoconjugates. Glycosylation of bovine serum albumin and chymotrypsin were chosen as examples of an application of the described compounds. The glycosylating agents can modify not only amino groups, but also alkyl hydroxyl and aryl hydroxyl groups, as was shown in experiments with model water soluble and water insoluble polyacrylamide copolymers.

Water-soluble poly(acrylamide-allylamine) derivatives of saccharides for protein-saccharide binding studies

Water-soluble poly(acrylamide-allylamine) copolymers containing covalently bound amino groups, prepared by copolymerization of acrylamide and allylamine, can be used as general carriers for coupling of different types of saccharides or saccharide derivatives. The water-soluble macromolecular carbohydrate derivatives can be easily labelled and used in various solid-phase techniques to study protein-saccharide interaction. Two types of coupling reaction were used to prepare polyacrylamide derivatives of saccharides: reductive amination was applied to couple the reducing disaccharides and a carbodiimide reaction was used to couple heparin via its carboxyl groups to the amino groups of the poly(acrylamide-allylamine) derivative. Peroxidase labelled or biotinylated derivatives were shown to be useful in studies on the binding properties of lectins and proteins from boar seminal plasma.