Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0267964 (PAA)
 2,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thirty-five Salmonella strains isolated from human cases of salmonellosis were tested and compared for their fibronectin (fn) binding capacities by using two fn-particle agglutination assays (fn-PAAs) prepared by coating with human fn either (i) latex beads (Difco; 0.81-micron diameter) (L-fn-PAA) or (ii) heat-killed formalin-treated Staphylococcus aureus Cowan 1 cells (C-fn-PAA). Six S. aureus strains were also included in this study as controls. The strains were cultured on colonization factor antigen agar and blood agar and in tryptic soy broth and brain heart infusion broth. The Salmonella and S. aureus strains were cultured at 33 and 37 degrees C, respectively, for optimal expression of fn-binding proteins. Bacterial cells (approximately 10(10) cells per ml) harvested from growth in various culture media and suspended in 0.02 M potassium phosphate buffer (pH 6.8) agglutinated the fn-PAA reagents. These reactions were scored semiquantitatively from + to + depending on the speed or intensity of the reactions within 2 min. Maximum agglutination in fn-PAA systems was observed when the cells were grown in brain heart infusion broth, while tryptic soy broth proved to be least suitable media for culturing cells for fn-PAAS. Although a statistically highly significant correlation was obtained between results of assays of radiolabeled fn and 29-kDa fragment binding, no significant correlation was observed (i) between the results of strains cultured in different media or (ii) when semiquantitative score results of the two fn-PAA systems were compared with those of the conventional radiolabeled fn assay. To enhance the efficiency of the test system, the C-fn-PAA reagent was stained with methylene blue (2% in 0.17 M glycine-NaOH buffer [pH 6.8]). This facilitated easy interpretation of results, which could be performed on hydrophobic paper instead of glass slides. The results obtained with both unstained C-fn-PAA and stained C-fn-PAA were comparable to each other and reproducible. Although the fn-PAAs are simple and easy to perform, the results did not differentiate between negative, low, moderate, and high binding abilities when Salmonella strains were evaluated for fn binding, and the results were not comparable to those obtained by the conventional radiolabeling method.
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PMID:Fibronectin binding by Salmonella strains: evaluation of a particle agglutination assay. 175 55

Hydrogen-bonded multilayers comprised of polyacrylamide (PAAm) and a weak polyelectrolyte, such as poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMA), were investigated for their surface-cell interactions. The assembled films were lightly cross-linked thermally or photochemically in order to render them stable in a physiological environment. Both PAA/PAAm and PMA/PAAm multilayers were found to exhibit a high resistance to the adhesion (cytophobicity) of mammalian fibroblasts, even with only a single bilayer coating. Protein adsorption to the multilayers, as revealed by surface plasmon resonance measurements, was greatly reduced for fibronectin and serum-containing medium. In situ swelling experiments indicate that the H-bonded multilayers are hydrogellike coatings capable of a high level of swelling in buffered solution. Utilizing the H-bonding nature of these multilayers, we were able to micropattern the films to create more complex cell-resistant/-adhesive surfaces. The long-term stability of the cell-resistant multilayers was found to be exceptionally good even under conditions (pH 7.4, buffered solution) where a high degree of swelling takes place. No degradation of the micropatterned films was observed over a period of a month, during which time the multilayer coatings remained highly resistant to cell-adhesion.
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PMID:New class of ultrathin, highly cell-adhesion-resistant polyelectrolyte multilayers with micropatterning capabilities. 1285 83

Culture of A7r5 smooth muscle cells on a polyelectrolyte multilayer film (PEMU) can influence various cell properties, including adhesion, motility, and cytoskeletal organization, that are modulated by the extracellular matrix (ECM) in vivo. ECM contribution to cell behavior on PEMUs was investigated by determining the amount of fibronectin (FN) bound to charged and hydrophobic PEMUs by optical waveguide lightmode spectroscopy and immunofluorescence microscopy. FN bound best to poly(allylamine hydrochloride) (PAH)-terminated and Nafion-terminated PEMUs. FN bound poorly to PEMUs terminated with a copolymer of poly(acrylic acid) (PAA) and 3-[2-(acrylamido)-ethyl dimethylammonio] propane sulfonate (PAA-co-AEDAPS). Cells adhered and spread well on the Nafion-terminated PEMU surfaces. In contrast, cells spread less and migrated more on both FN-coated and uncoated PAH-terminated PEMU surfaces. Both cells and FN interacted much better with Nafion than with PAA-co-PAEDAPS in a micropatterned PEMU. These results indicate that A7r5 cell adhesion, spreading, and motility on PEMUs can be independent of FN binding to the surfaces.
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PMID:Fibronectin and cell attachment to cell and protein resistant polyelectrolyte surfaces. 1628 53

The interaction of the proteins bovine serum albumin (BSA), lysozyme (Lys), lactoferrin (Lf), and fibronectin (Fn) with surfaces of protein-resistant poly(ethylene oxide) (PEO) and protein-adsorbing poly(acrylic acid) (PAA) fabricated by plasma-enhanced chemical vapor deposition has been studied with quartz crystal microbalance with dissipation monitoring (QCM-D). We focus on several parameters which are crucial for protein adsorption, i.e., the isoelectric point (pI) of the proteins, the pH of the solution, and the charge density of the sorbent surfaces, with the zeta-potential as a measure for the latter. The measurements reveal adsorption stages characterized by different segments in the plots of the dissipation vs frequency change. PEO remains protein-repellent for BSA, Lys, and Lf at pH 4-8.5, while weak adsorption of Fn was observed. On PAA, different stages of protein adsorption processes could be distinguished under most experimental conditions. BSA, Lys, Lf, and Fn generally exhibit a rapid initial adsorption phase on PAA, often followed by slower processes. The evaluation of the adsorption kinetics also reveals different adsorption stages, whereas the number of these stages does not always correspond to the structurally different phases as revealed by the D- f plots. The results presented here, together with information obtained in previous studies by other groups on the properties of these proteins and their interaction with surfaces, allow us to develop an adsorption scenario for each of these proteins, which takes into account electrostatic protein-surface and protein-protein interaction, but also the pH-dependent properties of the proteins, such as shape and exposure of specific domains.
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PMID:pH-dependent immobilization of proteins on surfaces functionalized by plasma-enhanced chemical vapor deposition of poly(acrylic acid)- and poly(ethylene oxide)-like films. 1854 95

We developed a cell-based assay based on the spin-assisted layer-by-layer (LbL) assembled polyelectrolyte matrix platforms. Three types of human breast epithelial cell lines including normal cells (184B5), noncancerous fibrocystic disease cells (MCF 10F), and metastatic cancerous cells (CAMA-1) were cultured, analyzed, and compared in parallel on various LbL-assembled polymer films. Poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) electrolyte polymers were used as the basic building units to form various LbL polyelectrolyte matrices. The mechanical rigidity, surface charge, and biorecognition property of the LbL platforms were controlled by tailoring the LbL surface, thermal cross-linking, and protein modification. Cellular phenotypic changes in adhesion, proliferation, and morphology on these LbL films were characterized and analyzed for the three different cell types. Our analysis results indicate that the cellular phenotype can be controlled by taking advantage of different surface charge, mechanical property, and biological modification (i.e., fibronectin in this case) of the LbL multilayer platforms. Importantly, cell phenotypical quantification results show that the cell spreading area per cell and optical density are useful parameters in distinguishing metastatic cancer cells from normal or fibrocystic disease cells on these LbL films. These LbL-based cell assay platforms have a potential for the development of various disease diagnostic cell assays.
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PMID:Tunable layer-by-layer polyelectrolyte platforms for comparative cell assays. 1957 97

The adhesive interactions of block copolymers composed of poly(methyl methacrylate) (PMMA)/poly(acrylic acid) (PAA) and poly(methyl methacrylate)/poly(2-hydroxyethyl methacrylate) (PHEMA) with the proteins fibronectin, bovine serum albumin and collagen were studied by atomic force microscopy. Adhesion experiments were performed both at physiological pH and at a slightly more acidic condition (pH 6.2) to model polymer-protein interactions under inflammatory or infectious conditions. The PMMA/PAA block copolymers were found to be more sensitive to the buffer environment than PMMA/PHEMA owing to electrostatic interactions between the ionized acrylate groups and the proteins. It was found that random, diblock and triblock copolymers exhibit distinct adhesion profiles although their chemical compositions are identical. This implies that biomaterial nanomorphology can be used to control protein-polymer interactions and potentially cell adhesion.
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PMID:Bioadhesion of various proteins on random, diblock and triblock copolymer surfaces and the effect of pH conditions. 2114 31

We use patterned poly(acrylic acid) (PAA) polymer brushes to explore the effects of surface chemistry and topography on cell-surface interactions. Most past studies of surface topography effects on cell adhesion have focused on patterned feature sizes that are larger than the dimensions of a cell, and PAA brushes have been characterized as cell repellent. Here we report cell adhesion studies for RBL mast cells incubated on PAA brush surfaces patterned with a variety of different feature sizes. We find that when patterned at subcellular dimensions on silicon surfaces, PAA brushes that are 30 or 15 nm thick facilitate cell adhesion. This appears to be mediated by fibronectin, which is secreted by the cells, adsorbing to the brushes and then engaging cell-surface integrins. The result is detectable accumulation of plasma membrane within the brushes, and this involves cytoskeletal remodeling at the cell-surface interface. By decreasing brush thickness, we find that PAA can be 'tuned' to promote cell adhesion with down-modulated membrane accumulation. We exemplify the utility of patterned PAA brush arrays for spatially controlling the activation of cells by modifying brushes with ligands that specifically engage IgE bound to high-affinity receptors on mast cells.
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PMID:Cellular responses to patterned poly(acrylic acid) brushes. 2155 46

The conformational changes of fibronectin (FN) deposited on various block copolymers where one block is composed of poly(methyl methacrylate) (PMMA) and the other block is either poly(acrylic acid) (PAA) or poly(2-hydroxyethyl methacrylate) (PHEMA) were investigated using a functionalized atomic force microscope (AFM) tip. The tip was modified with an antibody sensitive to the exposure of the arginine-glycine-aspartic acid (RGD) groups in FN. By studying the adhesive interactions between the antibody and the proteins adsorbed on the block copolymer surface and phase imaging, it was found that the triblock copolymers PAA-b-PMMA-b-PAA and PMMA-b-PHEMA-b-PMMA, which both have large domain sizes, are conducive to the exposure of the FN RGD groups on the surface. On the basis of these results, it is concluded that the surface chemistry as well as the nanomorphology dictated by the block copolymer arrangement could both tune protein conformation and orientation and optimize cell adhesion to the biomaterial surface.
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PMID:Block copolymer arrangement and composition effects on protein conformation using atomic force microscope-based antigen-antibody adhesion. 2227 46

The present study describes a live-cell biosensor, suitable for general evaluation of adhesion qualities of different substrates. It is based on NIH/3T3 fibroblast cell line stably expressing fusion fluorescently tagged proteins mCherry-vinculin and GFP-tensin as quantifiable markers for assessment not only of focal but also of fibrillar contacts. Four measurable parameters - spreading, polarization and development of focal and fibrillar adhesions were used to standardize the adhesion of biosensor cells after plating on five substrates of natural origin - fibronectin, vitronectin, laminin-111, laminin-521 and collagen type I. The obtained set of values (adhesion quality map) were utilized to describe the default biosensor behavior and as a standard for evaluation of surface biocompatibility of materials with unknown adhesive properties. To demonstrate the applicability of the biosensor we studied two PDMS-based artificial materials. The results demonstrated the superior adhesive properties of the poly(acrylic acid)-containing polymer (PDMS-PAA) over that of poly(vinyl pyrrolidone) copolymer (PDMS-PVP), and pointed out the formation of focal adhesions as a parameter for possible further improvements.
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PMID:Live-cell biosensor for assessment of adhesion qualities of biomaterials. 2857 79