Occurrence of glycosphingolipids in chicken egg yolk.

Chicken egg yolk was found to contain a unique glycosphingolipid pattern not seen in other types of tissue or cell. These glycosphingolipids were isolated in pure form and their structures established by sequential enzymic hydrolysis and permethylation analysis. The major gangliosides in chicken egg yolk are N-acetylneuraminosylgalactosylceramide, N-acetylneuraminosyl-lactosylceramide and di-N-acetylneuraminosyl-lactosylceramide. The only neutral glycosphingolipid found in chicken egg yolk is galactosylceramide.     

Nature of the thiamin-binding protein from chicken egg yolk.

A simple, rapid and efficient procedure for the purification of thiamin-binding protein from chicken egg yolk was developed. The method involved removal, by exclusion, of lipoproteins from DEAE-cellulose and subsequent elution of water-soluble proteins held on the ion-exchanger with 1 M-NaCl, followed by treatment of the eluted protein fraction with an aqueous suspension of dextran/charcoal to generate apoprotein from the holoprotein. The resultant protein fraction was subjected to bioaffinity chromatography on thiamin pyrophosphate--AE (aminoethyl)-Sepharose. The protein eluted specifically with 10 microM-thiamin at pH 7.0, was homogeneous by the criteria of polyacrylamide-gel disc electrophoresis, had a mol.wt. of 38 000 +/- 2000 and was not a glycoprotein. The purified thiamin-binding protein specifically interacted with riboflavin-binding protein with no detectable deleterious affect on its (14C)thiamin-binding capacity. The protein bound [14C]thiamin with a molar ratio of 1.0, with dissociation constant (Kd) 0.41 microM. This protein-ligand interaction was inhibited by thiamin analogues and antagonists. The absorption spectrum of the protein in the presence of thiamin exhibited significant hypochromism at the 278 nm band, indicating the involvement of aromatic amino acid residues of the protein, during its binding to the ligand. The protein cross-reacted with the monospecific antiserum to egg-white thiamin-binding protein, showing thereby that thiamin-binding proteins present in chicken egg yolk and white are the products of the same structural gene.     

Avidin traps biotin diffusing out of chicken egg yolk

1. The unequal distribution of biotin and biotin-binding proteins between the yolk and albumen of freshly laid chicken eggs provides the potential for time-dependent redistribution of biotin that could affect egg quality, biotin availability, and hatchability. 2. Avidin-bound biotin was measured in albumen next to the shell and next to the yolk in eggs stored up to 23 days. 3. Biotin bound to biotin-binding proteins (BBP-I and BBP-II) was measured at the center and periphery of yolk from the same eggs. 4. After 11 days of storage, significant amounts of biotin from the yolk began to accumulate in the albumen adjacent to the yolk. 5. This transfer is attributed to a change in the vitelline membrane that permits diffusion of biotin, not BBP-I or BBP-II, out of the yolk. 6. The dynamics of this phenomenon suggest that in addition to its antimicrobial role, avidin may be involved in the utilization of biotin by the chick embryo.     

Thermotropic behavior of liposomes from egg yolk lecithin, hydrogenized egg yolk lecithin and their mixtures

The thermotropic properties of multilamellar liposomes from egg yolk lecithin, hydrogenized egg yolk lecithin and several mixtures of these two lipids were studied with the application of excimer--forming optical probe pyrene and microcalorimetry. It was discovered that when the proportion of the egg yolk lecithin in the lipid mixture was raised the temperature of the main phase transition reduced. For all this, independent of the lipid mixture composition when the temperature was raised, apparently, polarity of pyrene microenvironment in the liposomes bilayers decreased. On the basis of the analysis of solidus and liquidus curves obtained from calorimetric studies of the lipid mixtures and bend points of Arrhenius anamorphose obtained during the pyrene excimer formation measurements some conclusions were made about the role of unmodified and hydrogenized egg yolk lecithin cluster formation in the determination of thermotropic properties of the liposomes from the above two lipids mixtures. High temperature phase transition discovered for the egg yolk lecithin while measuring the pyrene excimer formation is proposed to be closely connected with temperature-dependent changes in the organization of phospholipid heads on the interphase bilayer/H2O solution.     

Production and purification of IgY antibodies from chicken egg yolk

The isolation of polyclonal antibodies from the serum of immunized mammals has significantly contributed to scientific research and diagnosis. The fact that recent technologies allow the production of antibodies in the yolk of eggs laid by hens, has led to the development of an alternative method for antibody generation that is less stressful to animals. As hens are kept under almost all their natural conditions, antibodies are isolated from the collected eggs; this technology is expected to become an interesting alternative to the conventionally serum-based techniques that eventually require to sacrifice the animal.Here we present a modified protocol for the isolation of IgY antibodies from immunized chickens and provide comparison between two chicken breeds in relative to IgY yield per egg. Our results show the possibility of generating large quantities of highly pure IgY from chicken eggs and also show large differences in the yield of IgY production between the two studied breeds. The results of this work indicate that IgY technology can be used for the production of primary antibodies for immunological work and disease diagnosis.     

Apolipoproteins and lipoprotein families in chicken embryos and egg yolk.

1. Turkey anti-LP-A and anti-LP-B cross react strongly with whole adult chicken serum. 2. Similar reactions occur with whole chicken embryo sera (10-21 days of incubation) and egg yolk fluid. 3. Ultracentrifugation of sera from 14-day old chicken embryos, after reaction with anti-LP-B, reveal complete precipitation of the VLDL and LDL of embryo serum (indicating that adult-type LP-B is the major apolipoprotein of these density classes). 4. All of the chicken embryo adult-type apo-LP-A is in the HDL fraction. 5. However, egg yolk and hen serum VLDL contain apo-LP-A as well as apo-LP-B.     

New genetic polymorphism recognized in the prealbumin region of chicken egg yolk1

Two-dimensional electrophoretic analysis of water-soluble proteins of chicken egg yolk was done by a first-dimension separation in agarose gel (pH 8.6) followed by a second-dimension separation in horizontal polyacrylamide gel (pH 9.0). Genetic polymorphism of a protein, tentatively designated as Pr M prealbumin, was observed. The analysis of family data suggests that the Pr M prealbumin is controlled by two alleles, Pr M⁺ and Pr M-, at a single autosomal locus. The Pr M⁺ allele appears to be dominant to the Pr M^- allele.     

The purification of IgY from chicken egg yolk by preparative electrophoresis

Chicken IgY has been purified from egg yolk by preparative electrophoresis on the Gradiflow, a system which has been employed for the purification of a wide range of proteins with high recovery and biological activity. Protein purification on the Gradiflow utilises electrophoresis with selected combinations of porous membranes and buffers. The purification of IgY was achieved by initial PEG lipid precipitation, then a single step Gradiflow run by a strategy based on the relatively high pI range of IgY compared to other egg yolk proteins. The IgY yields obtained from the delipidised supernatant are consistently greater than 80% by immunoassay. The purity of the IgY fraction compared favourably with IgY prepared using three commercial products.     

Purification and partial characterization of a cobalamin-binding protein from chicken egg yolk

Cobalamin-binding protein has been purified from chicken egg yolk by using DEAE-cellulose with a NaCl gradient. The resultant protein fraction was subjected to bioaffinity chromatography. The Mr was 38,000 by SDS-PAGE and 39,000 by gel filtration, and indicated that it was a glycoprotein. The Stokes radius was 4.3 nm and the pI 4.1. The protein bound 57CO.B12 with a molar ratio of 1:1 and a Kd of 0.41 microM. The CBP composed 296 amino acids residues. The protein-ligand interaction was inhibited by Cbl analogues.     

Efficient production of chicken egg yolk antibodies against a conserved mammalian protein

The egg yolk of immunized chicken is a rich and inexpensive source of specific polyclonal antibodies. In this paper we show that 20-30 micrograms of a highly conserved mammalian protein, as exemplified by proliferating cell nuclear antigen, are sufficient to induce an immune response. Immunoblot analysis revealed that specific antibodies appeared 20 days after immunization, reached a plateau after 30 days, and remained high until at least day 81. A total amount of 4 g immunoglobulin was extracted from 62 eggs of one immunized hen, yielding approximately 130 mg of specific antibodies.     

Lipopolysaccharide-specific IgG in egg yolk from two chicken flocks infected with Salmonella enteritidis

An indirect enzyme-linked immunosorbent assay (ELISA) was used to determine levels of IgG reacting with lipopolysaccharide from Salmonella enteritidis in samples of egg yolk from broiler breeder and egg-laying flocks, some of which were known to be infected with S. enteritidis. There was positive correlation between infection with salmonella and a high reading in the ELISA.     

An improved method for isolation of anti-viper venom antibodies from chicken egg yolk

The production of antibodies and its purification from mammalian blood has been found low yielding and laborious. Therefore, anti snake venom antibodies for therapeutic use is obtained mostly as polyvalent whole serum or partially purified polyvalent immunoglobulin. The side effects of anti snake venom (ASV) therapy are mainly serum sickness and renal failure, which may be reduced by using sufficiently pure antibodies. Therefore, we have standardized a simple method for production of purified antivenom. Here, we present the development of polyclonal antibodies against viper venom in hens and its isolation from the egg yolk of immunized birds. We have modified the reported methods of purification of immunoglobulin from egg yolk, and thus yielded 90% purity of the protein. The modified method involves only two steps, such as removal of lipids from the diluted egg yolk by a freeze-thaw cycle and centrifugation, followed by gel filtration on Biogel P-150. The advantages are that the process is very simple, and from one egg, 100+/-20 mg of pure immunoglobulin is obtained. The antibodies are present in the egg for up to 100 days after the immunization. Thus, using small amounts of venom, a large quantity of the immunoglobulin is obtained in a sufficiently pure form. The antigen binding ability of the pure antibody is found good by the Ouchterlony's double diffusion experiment.     

Isolation and partial characterization of polymorphic prealbumins from chicken egg yolk and serum

Polymorphic prealbumins (Pa A, Pa AB and Pa B) from hen's egg yolk ( Gallus gallus L.) were isolated by gel filtration. Prealbumin was homogeneous on immunoelectro-phoresis, gel filtration, and ion-exchange chromatography, but heterogeneous on starch gel electrophoresis (five bands). The heterogeneity could be removed by neuraminidase treatment. Some physical and chemical properties were determined, namely molecular weight (19,500), N-terminal amino acid (aspartic acid), isoelectric point (pH 4.6-4.7), A^1%_1cm,280nm value (18.5), absorption spectrum, solubility at different conditions, and the effect of heating. Amino acid composition was estimated too, and the presence of about 4% hexose was proved.     

Affinity purification of immunoglobulins from chicken egg yolk using a new synthetic ligand

Due to the peculiar composition of the egg yolk and the lack of specific affinity ligands, Y immunoglobulins are normally purified using complex and time consuming procedures involving a combination of precipitation and chromatographic steps first to extract and capture and then to polish IgY. In this study, we have examined the applicability for IgY affinity purification of TG19318, a synthetic ligand for immunoglobulin, obtained from the screening of combinatorial libraries, and already characterized for its capability to purify immunoglobulins of class G, M, E and A. Soluble proteins were separated from the lipidic fraction of egg yolk by the water dilution method and loaded on to TG19318 affinity columns prepared by immobilizing the ligand on the commercially available support Emphaze™. In a single chromatographic step TG19318 affinity columns led to an efficient capture of IgY directly from crude samples, and with a purity degree higher than 90%, as determined by densitometric scanning of SDS–PAGE analysis of bound fractions, and with full recovery of antibody activity, as determined by ELISA assay. Higher recovery and purity of IgY was obtained by using loading buffers at pH close to 6.5. Column capacity, determined by applying 4× excess IgY to 1 ml bed volume column, and eluting the retained immunoglobulins, was close to 65 mg of IgY per ml of resin. Chemical and chromatographic stability of TG19318/Emphaze was tested before and after various treatments. The derivatized matrix was found to be very stable, in terms of ligand leakage and maintenance of IgY binding capacity, under conditions of normal column usage, cleaning and storage.     

抗中华眼镜蛇毒鸡卵黄抗体的制备及其效价测定

目的探索免疫鸡制备高效价抗眼镜蛇毒抗体的新方法。方法用中华眼镜蛇原毒作抗原免疫22周龄的莱航母鸡,水溶法粗提抗体,DEAE Sepharos FF柱纯化,切向流超滤膜脱盐及浓缩,免疫电泳及双向免疫扩散法进行鉴定及效价测定,采用BCATMProte in Assay K it测定蛋白含量。结果鸡卵黄经水溶法的粗提物与中华眼镜蛇毒即有较明显沉淀反应,其效价随着纯度的提高而增强。将马源性抗血清的蛋白质含量调至与浓缩的IgY相同(2mg/m l),经双向免疫扩散及免疫电泳鉴定,该抗体不但对中华眼镜蛇毒有特异性结合,与孟加拉眼镜蛇毒亦有较强的交叉免疫活性,其效价较马抗眼镜蛇毒血清高4倍以上。结论用中华眼镜蛇原毒制备的IgY抗体,其效价较马抗血清有显著提高,并与孟加拉眼镜蛇毒有高度交叉免疫。本实验为抗眼镜蛇IgY的应用及其它抗蛇毒IgY的制备奠定了基础。     

Identification of N-acetylglucosamine-binding immunoglobulins in chicken egg yolk and serum distinct from the major mannose-binding immunoglobulins.

An N-acetyl-D-glucosamine (GlcNAc)-binding protein of 170 kDa has been isolated from hen serum and egg yolk. Another GlcNAc-binding protein of higher molecular mass was present only in the serum. The 170 kDa protein co-electrophoresed and co-chromatographed in gel filtration with a chicken IgG, and behaved identical to chicken IgG in double immunodiffusion with goat anti-chicken gamma chain antiserum. The sugar-binding hierarchy for the serum and yolk binding proteins, determined with bovine serum albumin neoglycoproteins, was GlcNAc greater than N-acetyl-D-galactosamine greater than glucose = galactose = L-fucose greater than mannose. This hierarchy was unlike any previously reported GlcNAc-binding proteins. The larger serum binding protein component was shown to be an IgM by double immunodiffusion with goat anti-chicken mu chain antiserum. The serum and yolk GlcNAc-binding proteins comprise a unique set of sugar-binding immunoglobulins distinct from the previously reported hen serum and yolk mannose-binding proteins (Wang et al., 1986).     

Purification and characterization of benzoyl-L-tyrosine ethyl ester hydrolase from the yolk sac membrane of chicken egg

An enzyme which hydrolyzes benzoyl-L-tyrosine ethyl ester (BTEE) was purified from yolk sac membranes of day-18 chick embryos. The purified BTEE hydrolase has a molecular weight of 110,000, being composed of 70,000 and 40,000 subunits, and preferred synthetic substrates for chymotrypsin to those for trypsin. The optimum pH and temperature of this enzyme were 6.5-7.0 and 40 degrees C, respectively. The Km value for BTEE of the enzyme was 16 mM at pH 6.5 and 30 degrees C. The enzyme was inhibited markedly by some chymotrypsin inhibitors but scarcely inhibited by trypsin inhibitors. Magnesium ion acted as potent activator, depending on the enzyme purity and its concentration, whereas p-chloromercuribenzoate and zinc ion inactivated the activity markedly. The BTEE hydrolase was found to hydrolyze proteins such as casein and hemoglobin. These data indicated that the enzyme is a proteinase similar to chymotrypsin. This proteinase could act on yolk proteins, suggesting that it plays an important role in the metabolism of yolk at the yolk sac membrane layer.