Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LACTOGLOBULINS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 811 records · Page 45Linked to original sources
PubMedDate not supplied

[The action of lactoperoxidase, lactoferrin and lactoglobulin on Shigella sonnei in an in-vivo experiment].

The synergism of the protective action of lactoperoxidase, lactoferrin and lactoglobulin obtained from cow milk, as well as lactoferrin obtained from human milk, was shown in experiments on white mice, infected intranasally with S. sonnei and used as an experimental model. The combined administration of these preparations in doses, each one having no protective action, contributed to the elimination of the bacteria from the lungs and prevented the death of the animals. This phenomenon was found to be nonspecific and suitable for use in the development of preparations for passive immunization against a wide spectrum of microorganisms.

Animals↗
PubMed1997

Cloning and sequence analysis of the 5'-flanking region of goat beta-lactoglobulin gene.

We were the first to report 5'-flanking sequences of goat beta-lactoglobulin (beta LG) gene (867 bp) including a promoter (770 bp) and part of the first exon (97 bp). The fragment was isolated from Chinese goat tissue with PCR, and then cloned and sequenced. Sequence comparison showed 94.6% homology with sheep and 88% homology with cattle, respectively. There are highly conserved transcription factor binding sites as well. It suggested that the proximal 406 bp of 5'-flanking sequences of sheep beta LG possess strong tissue-specific DNAaseI-hypersensitive sites. Sheep beta LG transgenes containing only the 406-bp 5'-flanking sequences were efficiently expressed in the mouse mammary gland at a high level. These goat beta LG 5'-flanking sequences could possibly direct heterologous protein expression in the milk of transgenic animals.

Animals↗
PubMed1998

3-Hydroxyphthaloyl beta-lactoglobulin. IV Antiviral activity in the mouse model of genital herpesvirus infection.

The spread of sexually transmitted infections caused by herpes simplex virus type 2 (HSV-2) has continued unabated despite educational efforts generated in response to the human immunodeficiency virus (HIV) epidemic. Given the absence of effective vaccines, this indicates the need to develop prophylactic measures such as topical antiviral agents. Chemical modification of bovine beta-lactoglobulin (beta-LG), the major protein of whey, by hydroxyphthalic anhydride (3HP) led to the generation of a potent HIV-1 inhibitor designated 3HP-beta-LG. This agent was shown to also have antiviral activity against HSV-2 and HSV-1 in vitro. Recent studies indicate that 3HP-beta-LG binds to HSV-1 virions, which, at least in part, involves the viral glycoprotein gE. Here we show that 3HP-beta-LG inhibits HSV-2 infection in the mouse model of genital HSV-2 infection. Simultaneous exposure to HSV-2 and 3HP-beta-LG caused a significant decrease in the proportion of infected animals (27% virus shedding, 5% lesion development and 0% fatality for 3HP-beta-LG as compared to 80% shedding, 60% lesion development and 53% fatality in mice treated with PBS). The proportion of animals with HSV-2 infection after treatment with beta-LG was similar to that in the PBS-treated group. Pretreatment with 3HP-beta-LG formulated in a gel, which prolongs the presence of the agent in the vagina, also significantly reduced the proportion of HSV-2-infected mice (5% virus shedding, 5% lesion development and 0% fatality for 3HP-beta-LG as compared to 70% shedding, 60% lesion development and 40% fatality in vehicle-treated mice). These differences were significant (P < or = 0.0005, 0.002 and 0.008 for shedding, lesion development and fatality, respectively). Virus titres in the minority of mice that developed infection were similar to those in untreated mice. HSV-2 infection was not inhibited by treatment of an ongoing infection, indicating that 3HP-beta-LG interferes with the initial infection. These data suggest that 3HP-beta-LG may be an efficacious agent for preventing vaginal transmission of genital herpesvirus infections.

Animals↗
PubMed1997

Conformation of beta-Lactoglobulin Studied by FTIR: Effect of pH, Temperature, and Adsorption to the Oil-Water Interface.

The structure of mixed A and B genetic variants of beta-lactoglobulin (beta-lg) in its native and denatured states has been studied by FTIR. The denaturation was achieved through either heating at various temperatures at pH 6 and 7 or by adsorption to the surfaces of oil droplets in oil-in-water emulsions. The time dependence of the structural changes of the adsorbed protein was also studied. It was found that beta-lg was more resistant to heat denaturation at pH 6 than at pH 7. Conversely, the adsorbed protein appeared to be more deformable at pH 6 than at pH 7. Although heating at lower temperatures (70 and 80 degreesC) for a longer time causes extensive denaturation, as does heating at higher temperature (90 degreesC) for a short time, the structure of the denatured protein was different in the two cases. When denatured at lower temperatures, more beta-structure remained as indicated by the presence of bands around 1632 cm-1 in the IR spectrum, whereas evidence for extensive intermolecular beta-structure was found on the sample heated at higher temperature, indicated by the strong adsorption band at 1684 cm-1. This explains that although gelation of the protein can be achieved in both cases, the gel structure may be different. Denaturation of beta-lg during heat treatment and upon adsorption appears to occur via similar intermediate structures, which begin with the loss of beta-sheet structure, but whereas heat denaturation generates more intermolecular beta-sheet and a small amount of unordered structure, adsorption of the protein to the oil-water interface induces a larger amount of unordered structure and a small amount of intermolecular beta-sheet. The denaturation of beta-lg on the interface is a much slower process compared to heat denaturation; even though some changes are detectable shortly after the adsorption of the protein, more extensive denaturation occurs during storage of the emulsions for 72 h. Copyright 1997 Academic Press.

Journal Article↗
PubMed1999

Neutron Reflectivity Study of the Adsorption of beta-Lactoglobulin at a Hydrophilic Solid/Liquid Interface.

Adsorption of a globular protein on a hydrophilic solid/liquid interface was investigated. Neutron reflectivity was used to determine structural information on an adsorbed beta-lactoglobulin layer at a hydrophilic silicon surface. The thickness of the protein film was found to be compatible with the diameter of the native protein, indicating that possible conformational changes of the protein during adsorption are not gross enough to alter the shape of the protein. The amount adsorbed is consistent with that derived by our ellipsometry measurements, obtained in similar experiments. Evidence for significant H-D exchange in the adsorbed protein was found. Copyright 1999 Academic Press.

Journal Article↗
PubMed1988

Beta lactoglobulin homologue placental protein 14 (PP14) in serum of patients with trophoblastic disease and non-trophoblastic gynecologic malignancy.

Serum levels of beta lactoglobulin homologue placental protein 14 (PP14) were measured by a sensitive radioimmunoassay in various trophoblastic diseases and non-trophoblastic gynecologic malignancies. While trace amounts of protein were detected in sera of non-pregnant subjects (22.3 +/- 13.7 micrograms/l), during first half of normal pregnancy a dramatic rise of serum-PP14 levels was demonstrable with a peak-value at 7th-10th week of gestation, followed by a decline thereafter. Serial determinations of PP14 have been performed in 31 patients with trophoblastic tumour (20 hydatidiform moles, 4 invasive moles and 7 choriocarcinomas). In patients with hydatidiform moles and invasive moles (273.5 +/- 106.5 micrograms/l and 162.2 +/- 109.6 micrograms/l) respective values before therapy were much exceeding the non-pregnant controls. After therapy there was a rapid decline of the serum-PP14 levels within two weeks. In patients with choriocarcinoma the PP14 values were moderately elevated (66.4 +/- 25.7 micrograms/l), and declined following the remission of disease. In 32 gynecological tumours (21 carcinomas of the cervix, 4 endometrial carcinomas, 5 ovarian carcinomas, 2 carcinomas of the vulva) the pretreatment levels were not different to normal controls.

Choriocarcinoma↗
PubMed2001

Study of beta-lactoglobulin/acacia gum complex coacervation by diffusing-wave spectroscopy and confocal scanning laser microscopy.

Complex coacervation has been investigated on mixtures of beta-lactoglobulin (beta-lg) and acacia gum (AG) at pH 4.2 where these two macromolecules interact electrostatically. Changes in beta-lg/AG complex coacervation induced by the presence of beta-lg aggregates were considered. The nature and structure of particles resulting from complex coacervation were determined by using confocal scanning laser microscopy (CSLM). CSLM revealed fundamental differences in the structure of each of the studied dispersions (at 1 wt.% total concentration). Spherical vesicular coacervates and precipitates (based on beta-lg aggregates) were the hallmark of BLG/AG dispersions (beta-lg dispersion containing insoluble aggregates). Only coacervates were visible in AF-BLG/AG dispersions (beta-lg dispersion free of insoluble aggregates). The latter were characterised by the presence of large foam-like coacervates induced by partial coalescence of single coacervates, especially at the 2:1 protein to polysaccharide (Pr:Ps) ratio. Diffusing wave spectroscopy (DWS) was used to study the stability of dispersions as a function of time. Depending on the Pr:Ps ratio and the presence of beta-lg aggregates, the intensity correlation function (g(2)(t)) shifted to lower correlation times rapidly after mixing of both macromolecules. This revealed the formation of a large number of small particles, characterised by faster Brownian motion. At 1 and 5 wt.% total concentration, the 8:1 Pr:Ps ratio exhibited a rapid decrease of the backscattered intensity in time, both for BLG/AG and AF-BLG/AG mixtures, revealing rapid sedimentation/coalescence of particles. This precluded the achievement of a stable correlation function. For the 2:1 Pr:Ps ratio, mixtures exhibited both coalescence and sedimentation phenomena as confirmed by shifts in the g(2)(t) towards larger correlation times and the decrease of the initial value of g(2)(t) with time. Mixtures obtained for the 1:1 Pr:Ps ratio were characterised by small variations in the DWS signal, emphasising the stability of produced particles. The increase of the total biopolymer concentration reduced the effect of both Pr:Ps ratio and presence of protein aggregates. From CSLM and DWS observations, possible differences in the complex coacervation mechanism in both types of mixtures were highlighted. The use of protein aggregates to control complex coacervation was underlined.

Journal Article↗
PubMed2001

Effect of limited hydrolysis on the interfacial rheology and foaming properties of beta-lactoglobulin A.

Hydrolysis of beta-lactoglobulin (beta-Lg), genetic variant A, using a serine protease specific for glutamic and aspartic acid residues from Bacillus licheniformis (BLP), resulted in improved foam overrun and foam stability. Limited hydrolysis (19-26% hydrolysed beta-Lg) led to a more rapid increase in the viscoelastic properties of air/water interfacial films and a concomitant increase in foam overrun compared with intact beta-Lg, presumably due to increased exposure of hydrophobic areas. The increased exposure did not, however, cause formation of an interfacial layer with increased viscoelastic properties. More extended hydrolysis (86% hydrolysed beta-Lg) resulted in a higher initial overrun than the unhydrolysed sample and the best foam stability. The interfacial elasticity and viscosity, though, was the lowest observed. Thus, high maximum values of these interfacial properties are not necessary prerequisites for formation of a voluminous and stable foam.

Journal Article↗
PubMed2001

Dilatational rheology and foaming properties of sucrose monoesters in the presence of beta-lactoglobulin.

The foaming properties and the dilatational rheology of systems containing purified sucrose caprylate (SM800), caprate (SM1000), laurate (SM1200) and palmitate (SM1600) have been studied. Addition of beta-lactoglobulin (beta-lg) at a low concentration (0.050 wt.%) can aid the foam formation in the cases, where the surfactant concentration is insufficient to support foam formation. However, foams where both species co-existed exhibited poor stability. beta-lg was found to affect the dilatational properties of surfactant films even at low concentrations. It is thought that this could be related to the effect of the protein on the adsorption-desorption relaxation mechanism, or to the possible formation of a protein-surfactant complex in the bulk. The age of the protein film was also found to affect the kinetics of protein displacement by SM1000, as monitored by the change in the dilatational properties (Langmuir trough technique) and the relative reflectivity of the interface (Brewster angle microscopy) with time. An insoluble monolayer of sucrose stearate (Suc18) and beta-lg was also studied and it was found that the presence of small amounts of Suc18 in the protein film lead to a reduction of the interfacial elasticity. This is believed to be due to the disruption of the protein network. A possible mechanism could involve the obstruction of the hydrogen-bond intermolecular protein association by the strongly hydrated sucrose headgroup or the obstruction of the protein-protein hydrophobic interactions by the formation of an interfacial protein-surfactant complex.

Journal Article↗
PubMed2001

Interactions, desorption and mixing thermodynamics in mixed monolayers of beta-lactoglobulin and bovine serum albumin.

The interactions between milk proteins, beta-Lactoglobulin (beta-Lg) and bovine serum albumin (BSA), at the air-water interface have been evaluated. The surface pressure (pi), molecular area (a) isotherms were obtained by compression of the monolayers at different pH and temperature. In the method used to calculate the interactions, the desorbed segments of the proteins into the aqueous subphase have been considered. Earlier, the desorbed segments have been estimated from the compressibility factor, z, as a function of the surface pressure (virial state equation). The main conclusion from this study is that for biopolymers it is not possible to apply only the mixing thermodynamics to evaluate the intermolecular forces. It is necessary to include the desorption phenomenon. From these results, we can conclude that the main interaction between both proteins is of electrostatic character.

Journal Article↗
PubMed2001

Modification of bovine beta-lactoglobulin by glycation in a powdered state or in aqueous solution: adsorption at the air-water interface.

The adsorption at the air-water interface of native and various glycated forms of beta-Lactoglobulin B (beta-LG), prepared under two different experimental conditions, was investigated by ellipsometry, surface tension and shear elastic constant measurements. The measurements were performed in 0.1 M phosphate buffer, 0.1 M NaCl, pH 6.8. It was found that the interfacial properties of beta-LG were more affected when the glycation was performed in solution than in the dry-way system. Dry-way glycated beta-LG, despite a higher glycation extent, affected slightly its interfacial behaviour. Solution glycated beta-LG exhibited a higher adsorption and more rigid interface as expressed by shear elastic constant measurement at saturation (16.5 mN/m against 8.7 and 11.5 mN/m for native and control treated beta-LG, respectively). These results were attributed to the specific molecular species induced during glycation in solution, which includes monomers and unfolded covalent homodimers of beta-LG molecules with a high tendency to self-association via non-covalent interactions.

Journal Article↗
PubMed2000

Identification of the human beta-casein C-terminal fragments that specifically bind to purified antibodies to bovine beta-lactoglobulin.

The presence of foreign proteins in human milk after the ingestion of bovine dairy products is thought to be one of the possible causes of allergic sensitization in exclusively breast-fed predisposed infants. The immunologic determination of bovine beta-lactoglobulin (LG) concentration in human milk has been reported by several researchers, but the results are conflicting. Moreover, a strong cross-reactivity between antibodies to bovine beta-LG and human milk proteins and peptides was reported, throwing doubt on the reliability of radioimmunoassay and enzyme-linked immunosorbent assay detection and quantification assays for bovine beta-LG in human milk. Thus, the goal of this study was to isolate human milk peptides with a molecular mass >or= 1,000 Da cross-reactive with antibodies to bovine beta-LG in order to identify possible common epitopes between human and bovine milk proteins. The proteins were first isolated by affinity chromatography with purified polyclonal antibodies to bovine beta-LG, followed by gel filtration fast phase liquid chromatography and reverse phase-high performance liquid chromatography purification of the components specifically bound in the affinity separation step. Affinity-bound peptides were identified by determining their amino acid sequence. All the sequenced peptides belonged to the C-terminal part of human beta-casein, which confirms the cross-reactivity of human milk proteins and peptides with antibodies to bovine beta-LG and allows the identification of possible common epitopes between the two proteins. No bovine beta-LG peptides with a molecular mass >or= 1,000 Da were found in our milk samples from healthy mothers on a diet rich in bovine milk and dairy products.

Journal Article↗
PubMed1992

Large scale extraction of alpha-lactalbumin and beta-lactoglobulin from bovine whey by precipitation with polyethylene glycol and partitioning in aqueous two-phase systems.

The milk proteins alpha-lactalbumin and beta-lactoglobulin have been isolated from bovine whey by fractional precipitation with polyethylene glycol (PEG) and hydrophobic partitioning in aqueous PEG-hydroxypropylstarch two-phase systems using PEG-bound palmitate as hydrophobic ligand. The possible use of this combination for large scale purification of these whey proteins is discussed.

Animals↗
PubMed1991

Effect of clomiphene citrate on the synthesis and release of the human beta-lactoglobulin homologue, pregnancy associated endometrial alpha 2-globulin, by the uterine endometrium.

As an extension to a previous study to examine the effects of clomiphene citrate (CC) on human chorionic gonadotrophin/luteinizing hormone (LH) receptors in human corpora lutea, we sought to determine the effect of CC on the synthesis of the beta-lactoglobulin homologue, pregnancy associated endometrial alpha 2-globulin (alpha 2-PEG) by the luteal phase human endometrium. Seventeen normally-cycling women aged 25.9 +/- 2.1 years (mean +/- SE), undergoing elective tubal ligation, were divided into four groups consisting of controls (n = 2) and three treatment groups. Each of the treatment groups (n = 5/group) was treated with either 50 mg (group 1), 100 mg (group 2) or 150 mg (group 3) of CC daily on days 5 to 9 of the cycle. Portions of endometrial tissue were obtained by curettage 7 to 9 days following the urinary LH surge and were either fixed for histological analyses or cultured in vitro in the presence of [35S]methionine. Tissue media (TCM) that were analysed by two-dimensional gel electrophoresis followed by fluorography indicated that the synthesis of alpha 2-PEG was most markedly reduced in groups 2 and 3. Densitometric scans of TCM Western blots and radioimmunoassay (RIA) of TCM showed that the overall synthesis of alpha 2-PEG decreased from 5.8 +/- 1.9 arbitrary units (AU) and 371.2 +/- 239.3 ng/ml in group 1 to 3.1 +/- 0.8 AU and 69.4 +/- 24.9 ng/ml, and 2.7 +/- 1.1 AU and 52.4 +/- 19.8 ng/ml in groups 2 and 3 respectively. On cycle days 20-22, control values were 5.8 AU and 498.1 ng/ml respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Immunohistological localization of human pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG), a glycosylated beta-lactoglobulin homologue, in the decidua and placenta during pregnancy.

Monoclonal and polyclonal antibodies to pregnancy-associated endometrial alpha 2-globulin (alpha 2-PEG), a glycosylated human beta-lactoglobulin homologue, were used in an immunohistological technique to determine the cellular localization of this protein in the decidua and placental tissues during pregnancy. During the first trimester the protein was principally localized to the glandular epithelium of the decidua spongiosa region of the endometrium with only weak staining associated with glands of the decidualized decidua compacta region. No significant cellular staining was detected in the decidua capsularis. At term in the decidua of the amniochorion and the placental bed weak staining for alpha 2-PEG was only associated with the epithelium of attenuated glands. No significant staining was detected in the placenta during pregnancy. These results suggest that the epithelium of glands associated with non-decidualized stroma represents the primary source of alpha 2-PEG during the first trimester and that a function of the decidua spongiosa in early pregnancy may be related to production of alpha 2-PEG. The decline in production of alpha 2-PEG during pregnancy is suggested to result from involution of the decidua spongiosa and at term the attenuated glands of the decidua represents the source of alpha 2-PEG.

Decidua↗
PubMed2003

[Goat beta-lactoglobulin gene cloning and high expression in the mammary gland of transgenic mice].

To clone goat beta-lactoglobulin (BLG) gene,two fragments were amplified from goat genomic DNA by LD-PCR method. The fragments were inserted in T-vectors before being spliced into the whole 7.2 kb BLG gene at a single restriction enzyme site of NarI. Consequently, the eukaryotic expression vector was constructed. All the clones were proved to be correct by restriction enzyme cutting and sequencing analysis. Six Founders (3 male symbol, 3 female symbol) of goat BLG transgenic mice were obtained by microinjection and BLG genes integration were confirmed by both PCR and Southern blot analyses. The milk was collected from two lactating female transgenic mice and goat BLG protein contents were measured with ELISA. The results showed that goat BLG protein in milk of the two mice were 23.49 mg/mL and 2.19 mg/mL, respectively.

English Abstract↗