Showing papers on "Bovine serum albumin published in 2003"

Binding of perfluorinated fatty acids to serum proteins.

Abstract: Perfluorooctane sulfonic acid (PFOS) accumulates in the liver and blood of exposed organisms. The potential for these surfactant molecules to interfere with hormone/protein interactions in blood is of concern given the importance of these interactions. The PFOS binding to serum proteins was investigated by assessing its ability to displace a variety of steroid hormones from specific binding proteins in the serum of birds and fishes. Perfluorooctane sulfonic acid had only a weak ability to displace estrogen or testosterone from carp serum steroid binding proteins. Displacement of cortisone in avian sera occurred at relatively low PFOS concentrations. Corticosterone displacement potency increased with chain length, and sulfonic acids were more potent than carboxylic acids. The PFOS concentrations estimated to cause these effects were 320 μM or greater, equivalent to serum concentrations greater than 160 mg/L. Using mass spectrometry and direct in vitro binding assays, PFOS was demonstrated to bind strongly to bovine serum albumin (BSA) in a 1:1 stoichiometric ratio. It appears that PFOS in serum is in general bound to albumins. Concentrations of PFOS required to saturate albumin would be in excess of 50 to 100 mg/L. Based on current environmental concentrations, it is unlikely that PFOS would cause displacement of hormones from serum proteins in wildlife.

Molecular packing of lysozyme, fibrinogen, and bovine serum albumin on hydrophilic and hydrophobic surfaces studied by infrared-visible sum frequency generation and fluorescence microscopy.

Abstract: Infrared-visible sum frequency generation (SFG) vibrational spectroscopy, in combination with fluorescence microscopy, was employed to investigate the surface structure of lysozyme, fibrinogen, and bovine serum albumin (BSA) adsorbed on hydrophilic silica and hydrophobic polystyrene as a function of protein concentration. Fluorescence microscopy shows that the relative amounts of protein adsorbed on hydrophilic and hydrophobic surfaces increase in proportion with the concentration of protein solutions. For a given bulk protein concentration, a larger amount of protein is adsorbed on hydrophobic polystyrene surfaces compared to hydrophilic silica surfaces. While lysozyme molecules adsorbed on silica surfaces yield relatively similar SFG spectra, regardless of the surface concentration, SFG spectra of fibrinogen and BSA adsorbed on silica surfaces exhibit concentration-dependent signal intensities and peak shapes. Quantitative SFG data analysis reveals that methyl groups in lysozyme adsorbed on hydrophilic surfaces show a concentration-independent orientation. However, methyl groups in BSA and fibrinogen become less tilted with respect to the surface normal with increasing protein concentration at the surface. On hydrophobic polystyrene surfaces, all proteins yield similar SFG spectra, which are different from those on hydrophilic surfaces. Although more protein molecules are present on hydrophobic surfaces, lower SFG signal intensity is observed, indicating that methyl groups in adsorbed proteins are more randomly oriented as compared to those on hydrophilic surfaces. SFG data also shows that the orientation and ordering of phenyl rings in the polystyrene surface is affected by protein adsorption, depending on the amount and type of proteins.

Photophysical Studies on Binding of Curcumin to Bovine Serum Albumin

Abstract: The excited-state photophysical properties of curcumin in the presence of bovine serum albumin (BSA) have been studied. The absorption and fluorescence changes in curcumin on binding to BSA have been followed at varying concentrations of either curcumin or BSA to determine the binding constant, which has been found to be approximately 10(4) to 10(5) M(-1). Stopped-flow kinetics studies suggested at least two distinct kinetic steps for the binding of curcumin to BSA. The photophysical properties of the singlet-excited state of the curcumin-BSA complex have also been studied. Whereas the absorption spectrum of curcumin is redshifted, the fluorescence spectrum of curcumin was blueshifted in the presence of BSA. The fluorescence quantum yield of curcumin on complexing with BSA was approximately 0.05. Steady-state fluorescence anisotropy studies showed a significant increase in the anisotropy value of 0.37 in BSA-bound curcumin. The fluorescence decay of the curcumin-BSA complex followed a biexponential decay with fluorescence lifetimes of 413 ps (33%) and 120 ps (67%). On the basis of these complementary results, it has been concluded that curcumin shows very high binding to BSA, probably at the hydrophobic cavities inside the protein.

Effects of Non-covalent Interactions with 5-O-Caffeoylquinic Acid (Chlorogenic Acid) on the Heat Denaturation and Solubility of Globular Proteins

Abstract: The non-covalent interactions between the monomeric phenolic compound chlorogenic acid (5-CQA) and bovine serum albumin (BSA), lysozyme, and α-lactalbumin were characterized, and their effect on protein properties was examined. 5-CQA had a low affinity for all three proteins, and these interactions seemed to show a negative cooperativity. 5-CQA-BSA binding decreased with increasing temperature, whereas pH (pH 3.0 compared to pH 7.0) and ionic strength had no pronounced effect. At high 5-CQA/protein molar ratios, both the denaturation enthalpy and temperature of BSA increased; however, covalent bonds were created at high temperatures. The presence of 5-CQA had no effect on the solubility of BSA and α-lactalbumin as a function of pH, whereas it decreased lysozyme solubility at alkaline pH due to covalent interactions. These results indicate that the non-covalent interactions with 5-CQA do not have pronounced effects on the functional properties of globular proteins in food systems.

Protein adsorption on titanium surfaces and their effect on osteoblast attachment

Abstract: The objective of this study was to investigate the adsorption of albumin and fibronectin on titanium (Ti) surfaces and the effect of preadsorbed albumin and fibronectin on osteoblast attachment in vitro. Bovine serum albumin and bovine fibronectin were used in this study. Maximum adsorption of bovine serum albumin and fibronectin on Ti surfaces was observed to occur after 180-min incubation. In the presence of preadsorbed proteins, osteoblast attachment on Ti surfaces was observed to be enhanced compared to control Ti surfaces. However, cell attachment was affected by the types of protein adsorbed. Preadsorbed albumin was observed to have no significant effect on the amount of osteoblast cells attached. In comparison to control Ti surface and Ti surfaces preadsorbed with albumin, Ti surfaces preadsorbed with fibronectin for 15 min was observed to significantly increase osteoblast cell attachment, whereas Ti surfaces preadsorbed with fibronectin for 180 min did not affect cell attachment. In addition, cell morphology of the attached cells on protein preadsorbed Ti surfaces was not affected by the type of protein used in this study. It was concluded from this study that the concentration of fibronectin adsorbed on Ti surfaces was higher compared to albumin. In addition, it was also concluded that the concentration of fibronectin on Ti surfaces plays a role in governing cell attachment.

Thermal stability of bovine serum albumin DSC study

Abstract: A calorimetric study of thermal denaturation of bovine serum albumin in aqueous solutions has shown essential differences in stability of fatty acid containing and defatted albumin. The first one shows a single endotherm peak in DSC curve near 69°C with enthalpy change about 1000 kJ mol-1. Defated albumin melts in two different temperature ranges: near 56 and 69°C with enthalpy changes about 300 and 200 kJ mol-1 respectively. Deconvolution analysis shows that the single endotherm is well approximated as the sum of three independent two-state transitions. Two transitions of bimodal DSC curve for defatted albumin are not of a two-state type. This molecule melts probably as two structurally independent parts.

Degradation of Micropatterned Surfaces by Cell-Dependent and -Independent Processes †

Abstract: This paper describes a study to determine the role of active cellular processes in the initial patterning and eventual degradation of different micropatterned substrates. We compared the effects of serum and cell type on the ability of cells to crawl onto the nonadhesive regions of a variety of patterned substrates. Cells initially patterned in the presence of serum onto substrates manufactured using agarose, pluronics, hexa(ethylene glycol), or polyacrylamide as the nonadhesive. While polyacrylamide remained inert and patterned cells for at least 28 days, agarose and pluronics degraded by gradual desorption of the nonadhesive from the surface independently of the presence of cells. Hexa(ethylene glycol) degraded by a time-dependent mechanism that could be accelerated by cell-dependent oxidative processes. In contrast to the other substrates studied, bovine serum albumin (BSA) patterned cells only under serum-free conditions. The serum did not displace BSA from the surface but instead activated cell-secreted proteases that led to degradation of the substrate. These findings illustrate the importance of specific cellular and noncellular processes in the failure of different nonadhesive chemistries commonly used to pattern cells.

Routes of FA delivery to cardiac muscle: modulation of lipoprotein lipolysis alters uptake of TG-derived FA.

Abstract: Long-chain fatty acids (FA) supply 70–80% of the energy needs for normal cardiac muscle. To determine the sources of FA that supply the heart, [14C]palmitate complexed to bovine serum albumin and [...

Interaction of magnolol with bovine serum albumin: a fluorescence-quenching study

Abstract: The interaction of magnolol with bovine serum albumin(BSA) was studied using fluorescence spectroscopy under physiological conditions. The binding constants, K, and the ratio of quantum yields of protein fluorescence for complex and free protein, f, at 298 K, 304 K, and 310 K were obtained; the values were 6.799x10(5) L mol(-1), 5.541x10(5) L mol(-1), and 4.344x10(5) L mol(-1) and 0.17, 0.30, and 0.34, respectively. The standard enthalpy change (delta H degrees ) and the standard entropy change (delta S degrees ) were calculated to be -28.53 kJ mol(-1) and 15.88 J mol(-1) K(-1), which indicated that hydrophobic forces played major role in the interaction of magnolol and BSA. The binding average distance between magnolol and BSA (4.32 nm) was obtained on the basis of the theory of Forster energy transfer.

Protein Overload Induces Fractalkine Upregulation in Proximal Tubular Cells through Nuclear Factor κB– and p38 Mitogen-Activated Protein Kinase–Dependent Pathways

Abstract: . Investigated was the effect of high albumin concentrations on proximal tubular cell expression of fractalkine. Human proximal tubular cells (HK-2) were incubated with human serum albumin (HSA), which induced a dose-dependent increase in fractalkine mRNA associated with increased levels of both membrane-bound and soluble forms of the protein. To evaluate the role of nuclear factor κB (NF-κB) activation in HSA-induced fractalkine mRNA, HK-2 cells were infected with a recombinant adenovirus encoding the natural inhibitor of NF-κB, IkBα; a 43% reduction of fractalkine mRNA levels resulted. Similarly, when cells were infected with the recombinant adenovirus expressing dominant negative mutant of the IkB kinase 2, a 55% inhibition of fractalkine mRNA was achieved. p38 mitogen-activated protein kinase was activated by HSA and was involved in NF-κB–dependent transcription of fractalkine. In kidneys of mice with bovine serum albumin overload proteinuria, fractalkine mRNA levels were 2.3-fold greater than those of controls. Fractalkine expression was also induced in tubular epithelial cells in this model. Anti-CXCR1 antibody treatment limited interstitial accumulation of mononuclear cells. Protein overload is a promoter of fractalkine gene induction mediated by NF-κB and p38 activation in proximal tubular cells. Fractalkine might contribute to direct mononuclear cells into peritubular interstitium and enhance their adhesion property, which in turn would favor inflammation and disease progression. E-mail: gremuzzi@marionegri.it

Protein-Conjugated Nanoparticles from Rapid Expansion of Supercritical Fluid Solution into Aqueous Solution

Abstract: The method of rapid expansion of a supercritical solution into a liquid solvent (RESOLV) was applied to the preparation of bovine serum albumin protein-conjugated silver sulfide nanoparticles. The conjugate samples were characterized by using a series of instrumental techniques. The results show that the monodispersed nanoparticles in the conjugates are well-coated directly with the protein. Because the protein undergoes solution pH-dependent association and dissociation, the protein-nanoparticle conjugates also assemble and disassemble with changes in solution pH in a reversible fashion.

Correlating fibronectin adsorption with endothelial cell adhesion and signaling on polymer substrates.

Abstract: Fibronectin (Fn) adsorption was studied on different commercial polymer surface chemistries, including tissue culture polystyrene (TCPS), bacteriologic polystyrene (BPS), fluoropolymer Teflon AF, and poly-L-lactide (PLLA). Antibody probes detected the availability of Fn's cell binding domain on adsorbed Fn in the competitive presence and absence of bovine serum albumin (BSA). Domain availability was highest for Fn adsorbed on TCPS, especially in the presence of either serum albumin or dilute serum. Attachment and growth efficiencies for human umbilical venous endothelial cells (HUVECs) cultured on surfaces preadsorbed with Fn in serum and serum-free media correlated with antibody cell-binding domain availability: TCPS > BPS, Teflon AF > PLLA. Intracellular signaling from the GTPase, RhoA, was highest (RhoA:RhoGDI inhibitor ratio) in cells cultured on the Teflon AF surfaces, indicating that despite lower attached cell numbers on Teflon AF compared to TCPS, cell signaling remained activated after 24 h of growth. Up-regulated cellular Fn mRNA messages, assessed using RT-PCR techniques, supported HUVECs' producing the endogenous extracellular matrix (ECM) protein Fn in order to attach and survive on the suboptimal Teflon AF culture surfaces.

Protein glycation inhibitory and antioxidative activities of some plant extracts in vitro

Abstract: The protein glycation inhibitory activity of aqueous ethanolic extracts from 25 plant tissues was evaluated in vitro using the model system of bovine serum albumin and fructose. The most bioactive ...

Cryo-survival and development of bovine blastocysts are enhanced by culture with recombinant albumin and hyaluronan

Abstract: Recombinant albumin can be used to supplement culture medium for the maturation and fertilization of bovine oocytes and subsequent embryo development to the blastocyst stage. Recombinant albumin was able to support blastocyst development at rates equivalent to that of bovine serum albumin (BSA) supplemented media. Supplementation of media containing recombinant albumin and citrate stimulated blastocyst expansion. Culture with recombinant albumin and citrate significantly increased the ability of the resultant blastocysts to re-expand and hatch following cryopreservation. The further addition of the glycosaminoglycan hyaluronan to the culture medium containing either BSA or recombinant albumin also increased the ability of blastocysts to survive cryopreservation. Inclusion of recombinant albumin and hyaluronan in culture media facilitates the development of physiological defined culture conditions. For bovine embryos this has implications for both research and commercial applications where defined reproducible conditions are desirable.