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Most data on the nutrient composition of shell eggs were obtained before 1950. Since then, management systems for egg production and analytical methods for many components have changed. Freeze-dried whole egg, yolk and white samples were prepared from eggs obtained from a single source of 15 month old White Leghorns. The sample were packaged under nitrogen and held at -20 degrees C. until analyzed. Conversion factors are included for expressing the amount of each component on a per egg as well as a per 100 g. edible liquid basis. This re-evaluation of nutrient data included total solids, lipid, protein, cholesterol, ash, calories, amino acids, fatty acids, vitamins and minerals.

Electrophoresis on celogel and staining the bands with Schiff's agent were used to study the sugar fractions in the diluents Nagase Niva, Triladil, Leciphos and GH22L (after Kichev) as well as in bull semen diluted to a various extent with the same media. Using combined staining--sugars/proteins--it was found that all sugar fractions in both media and diluted semen were bound with proteins. These biocomplexes were found to lower their electrophoretic mobility with the rising values of dilution. Discussed is the possibility to use the conformation of sugar complexes in the working out of new cryoprotective media.

Otherwise unavailable information concerning the distribution of phosphorylated compounds in biological systems is obtained by a combined solid-state/solution-state NMR approach, illustrated here for oocytes from Rana pipiens. General methodology is developed, and further extensions are proposed. The following conclusions pertain to the specific system under examination. (i) Nucleoside phosphates can be observed by magic-angle sample spinning of the lyophilized material. (ii) The solid-state NMR technique of dipolar decoupling provides no additional resolution of the phospholipid and phosphoprotein components of the yolk. However, cellular death produces sufficient pH changes to cause the phospholipid and protein phosphate peaks to become resolvable. The concentration of nucleoside phosphates also decreases. (iii) The phospholipid and phosphoprotein components are shown by computer simulation to be present in a ratio of 40:60, respectively. (iv) The amounts of inorganic phosphate, nucleoside phosphates, and sugar phosphates are determined by solution-state NMR observation of the perchloric acid extract of the oocytes.

In the yolk of the eggs of hens receiving traditional feeding hydrocarbon mixtures contained in trace amounts therein were analyzed by a specially elaborated method. For identification and quantification the data of the gas liquid chromatography, chromato-mass-spectrometry and ultraviolet spectrophometry were used. In a complex hydrocarbon mixture chromato-mass-spectrometry helped identify the alkanes of the normal and isoprenoid structure, cycloalkanes, of terpene and sterene types. The alkanes and cycloalkanes fraction content was found to comprise 15-30 per 1 mg of the raw mass of the yolk, of the p-alkanes--1-3 mg, squalene--15-17 mg and of monocyclic arenes--about 1 mg.

1. The non-specific hen's egg yolk alkaline phosphatase is a metalloprotein (Zn2+?) composed of two identical inactive subunits. 2. A second metal site preferably binds Mg2+ (15-fold activation). Me(II)(H2O)H+, a charged arginine, and tyrosine in the active site are involved in positioning and binding of the substrate and metal ion. 3. Substrate inhibition differs with pH. This may be related to the presence of two active sites in the enzyme, one in each subunit. 4. Uncompetitive inhibition with l-phenylalanine and analogues suggests a phosphorylated intermediate. 5. Inhibition is weakly competitive with Pi, strong non-competitive with PPi as compared to Mg2+- free PPi, and partially competitive with arsenate. 6. The purified enzyme is stabilized and activated by amines and proteins.

Chromatin prepared both from the yolk granules beneath the blastoderm and from the nuclei of the blastoderm cells of fertilized and unincubated chicken eggs was examined under electron microscope and its structure was compared. The results indicate that the above two kinds of chromatin fibers seem to have no apparent difference in structural relation and diameter. The electron microscopic appearances of the basic structures of both kinds of chromatin are all "beads-on-a-string"-shaped filaments. After the digestion of chromatin from both raw materials with DNase I, the connecting strings of chromatin fibers were cut off, only the scattered beads could be observed under electron microscope. The diameter of the scattered beads is equal to that of the beads on the chromatin fibers, and most of them are 150 A in diameter.

A method for the analysis of 25-hydroxycholesterol by high-performance liquid chromatography (HPLC) in a wide range of materials is described. Lipid extracts were initially purified on octadecyl silicic acid cartridges and by reversed-phase HPLC before quantitation by HPLC on a silicic acid column. The reproducibility of the method was confirmed by the analysis of plasma from rats fed 25-hydroxycholesterol. 25-Hydroxycholesterol was not detected in lard, cream, fresh egg yolk or spray-dried egg yolk powder. It was detected in egg yolk powder after heating at 110 degrees C for 4 days and its authenticity was confirmed by mass spectrometry.

We report an example of the enzymic cleavage of an apoprotein B (apoB), the main apoprotein in the very low density lipoprotein (VLDL) of laying hens' blood, in a normal biological process, the formation of egg yolk. Plasma VLDL was labeled in vivo with 3H-amino acids, isolated by centrifuging, and injected into another laying hen. Yolk VLDL was isolated and its apoproteins were separated. ApoB was not detected in this lipoprotein. Most of the label originally in apoB was distributed among four smaller yolk apoproteins, apovitellenins III to VI, which are a large proportion of the apoproteins of VLDL in yolk. This distribution of 3H suggested that 80% of apoB was cleaved at three places. One yolk apoprotein, apovitellenin II, was not labeled, indicating that it did not originate from an apoprotein in plasma VLDL. The site for cleavage of apoB in the ovarian tissue has not been determined, but cleavage may occur during receptor-mediated endocytosis. The pattern of cleavage of apoB during transfer to yolk was not imitated by some known proteolytic enzymes.

Active fractions that possess the hypocholesterolemic effect of iodine egg yolk lipid fraction have been investigated with male Wistar strain rats fed on a cholesterol-rich diet. Iodine egg yolk lipid was extracted by Folch's (chloroform: methanol) method and was refractionated into a neutral lipid (IEY-NL) fraction and a polar lipid (IEY-PL) fraction. The iodine content in each fraction was determined. The animals were kept on the cholesterol-rich diet for 5 days, and then they were fed the fractions in addition to the above diet for 10 more days. The hypocholesterolemic effect was seen most significantly with the IEY-NL fraction. The serum total cholesterol level in rats receiving this fraction was 70% as compared with that of the Ch group (fed on the cholesterol diet). However, the liver total cholesterol level was not affected or rather increased by the IEY-NL fraction. Another fraction (IEY-PL) showed no such effect. Iodine content in the IEY-NL fraction was quite low (0.2 ppm) compared with the other fractions. The daily dose in terms of iodine in the IEY-NL fraction was only the amount equivalent to 1/50 of the reported daily requirement for the rat. The IEY-NL fraction induced the hypocholesterolemic effect, though it contained only a trace of iodine.

The spin-lattice 13C-NMR relaxation time T1 of carbons in egg yolk phosphatidylcholine (EYPC) unilamellar liposomes was measured at 15 MHz, 25 MHz and 75 MHz in the presence of diamagnetic La3+ and paramagnetic Gd3+ ions. Supposing formation of ML2 complexes (where M is the metal ion and L the lipid) and using a simplified Solomon-Bloembergen-Morgan equation, a value of less than r-3IS greater than 2 = 0.1880 +/- 0.0005 nm-6 was obtained for C omega carbon of lipid chains, where rIS is the distance of Gd3+ unpaired electron and C omega nucleus, and angle brackets denote a weighted average. This value may serve as the basis for testing the application of statistical mechanics to lipid chain conformation and chain terminal group distribution in lipid bilayers.

Araucana eggs from six sources and commercial-type white eggs of two major supermarket brands and from the University of California flock were collected and analyzed for cholesterol content of the yolk. The yolks of Araucana eggs were significantly higher in cholesterol than those of commercial white eggs.

A comparative study has been made of the accumulation and synthesis of cholesteryl esters in the liver, yolk sac membrane, and yolk contents of the chick embryo during the last week of development. This involved a comparison of the cholesteryl esters synthesized during incubation in vitro with 14C-cholesterol with those accumulated during incubation in vivo. Results indicated that the considerable accumulation of cholesteryl esters, mainly cholesteryl oleate, that occurred within the liver during embryo development arose from synthesis in the yolk sac membrane. This suggested a specific role in the transport of yolk lipid into the embryo. With the approach of hatching the ability of the liver to synthesize its own cholesteryl esters increased while that of the yolk sac membrane decreased.

Actin was studied in Xenopus unfertilized eggs and early developmental stages. Immunochemical proof is given of structural differences between Xenopus laevis muscle actin and nonmuscle cell actin. Actin localization and changes of actin aggregation during Xenopus development were observed using indirect immunofluorescence. We have also tried to explain the presence of an actin shell around the yolk platelets that appeared in our experiments.

Increasing the fat content of the diet increases the proportion of large triglyceride-rich (TGR) lipoproteins (portomicrons) in laying-hen plasma, but has no effect on the size distribution of yolk TGR-lipoproteins. Electromicrographs of the ovarian follicle walls of hens fed a high-fat diet show the presence of numerous portomicron-like particles in the lumen of the thecal capillaries, in the pericapillary spaces and in the theca interna, but portomicrons were absent from the basal lamina, between the granulosa cells and in newly deposited yolk. Most of the lipoprotein lipase activity in the ovarian follicles is associated with the granulosa cells, but total activity in the follicle is very small compared to heart or adipose tissue. The results indicate that the ovarian follicle of the laying-hen specifically excludes lipoproteins of intestinal origin from yolk, most probably because they are too large to pass through the connective tissue matrix of the basal lamina. The low lipoprotein lipase activity of the ovarian follicle, together with its distribution within the follicle wall, indicates that the ovarian follicles make little contribution to catabolism of circulating portomicrons.

The capability of fast atom bombardment mass spectrometry for characterization of phosphorylation sites in a tryptic peptide from chicken egg yolk riboflavin-binding protein has been evaluated. The quality of information about molecular weight, amino acid sequence, phosphorylation sites, and microheterogeneity is evaluated as a function of the sign of the ions analyzed, the nature of the counter ions associated with the phosphate substituents, sample matrix, and various instrumental parameters. The intact octaphosphorylated 23-residue peptide was found to be susceptible to mass spectral analysis. Information from the negative ion spectrum was used in conjunction with complete sequence information and experiments which showed that all phosphates were attached to serine residues. Phosphorylated and unphosphorylated serine residues were identified and the sample was shown to be homogeneously octaphosphorylated.

The thiamin content of eggs laid by hens possessing no, one or two functional genes for riboflavin-binding protein is unaffected by the genotype. This does not support the hypothesis of Muniyappa & Adiga [Biochem. J. (1979) 177, 887-894] that the deposition of thiamin-binding protein is coupled to the deposition of riboflavin-binding protein.

A rapid and efficient method for the separation of egg yolk phospholipids by normal-phase high-performance liquid chromatography has been developed. The separation is accomplished on an Ultrasil-NH2 column using hexane, isopropanol, methanol and water mixtures with direct ultraviolet detection at 206 nm. Phospholipids from a methanol extract of fresh lyophilized egg yolks were analyzed providing complete separation of (in order of elution) neutral lipids, phosphatidylcholine, sphingomyelin, lysophosphatidylcholine and phosphatidylethanolamine. Identification of eluting species was accomplished by comparative retention times of standard samples by thin-layer chromatographic analyses of collected fractions. Furthermore, a mixture of naturally occurring phospholipid standards from bovine and egg sources has been separated by this method. In addition to separating the individual classes of phospholipids, in some instances, separation of molecular species within a class was achieved as in the case of cerebrosides, sphingomyelin and partially with phosphatidylethanolamine.

The title of this paper commemorating the contributions made by Professor Urist has an interesting bearing upon basic skeletal tissue biology. This is because the calcium-binding proteins (vitellogenins), upon which Professor Urist and Schjeide have focused much of their attention in non-mammalian vertebrates, although produced by the liver and present in the blood plasmas of non-mammalian vertebrates during vitellogenesis, are, in effect, substitutes for the protein casein present in the milk of mammalian vertebrates. Vitellogenins (180,000-250,000 daltons) appear to be produced solely for deposition in the yolk of the egg so that the calcium they carry (considerably more than is associated with casein of milk) and the amino acids of which they are comprised can be utilized during embryonic development. In many instances the progeny of non-mammalian vertebrates emerge from the shell as miniatures of the adult, capable of rapid movement and thus requiring a well developed skeletal as well as muscular system. Vitellogenins are not found in any other cells (phagocytes excepted) other than hepatocytes wherein they are made, nor are they present in the intercellular matrix of developing or remodeling bone. In non-vitellogenic females and in males of non-mammalian vertebrates, they are absent from the blood plasma altogether, so that nonionized calcium therein is solely bound to such proteins as albumin and the lipoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)

1. The amount of lipid decreased markedly at the later stage of embryonic development, coinciding with the remarkable decrease in yolk weight. 2. Phospholipase C activity in the yolk sac appeared on the 6th day of incubation and increased markedly as incubation proceeded. 3. The enzyme showed its optimum activity at pH 9.5 and at 40 degrees C. 4. The activity was enhanced 2-fold by 20 mM CaCl2 and by 40% by 4 mM deoxycholate but inhibited by 2 mM ZnCl2 and CuSO4.

Exposure of five-year-old L-929 cell monolayers to low-molecular-weight factor obtaiend from chicken egg-yolk fluids stimulated the production of Semliki Forest virus (SFV)-induced interferon, particularly when the cells were infected with a low-input multiplicity of SFV. The stimulatory effect on interferon production was not expressed in polyriboinosinic acid:polycytidylic acid-induced interferon. Furthermore, the high yield of interferon was correlated with and followed the increase in viral yield, thus suggesting that the yolk factor stimulates the growth of SFV, which in turn triggers the higher production of interferon. The outstanding feature of the yolk factor is its ability to stimulate the production of virus-induced interferon during the lytic cycle of virus replication.

A fast-heating probe and chemical ionization have been used to obtain mass spectra of the synthetic glycerophospholipids 1,2-diacyl-sn-glycero-3-phosphocholine, 1,2-diacyl-sn-glycero-3-phosphoethanolamine, and 1-monoacyl-2-lyso-sn-glycero-3-phosphocholine. The phospholipids investigated gave quasimolecular peaks and fragment ions, with preferential cleavage of the C-O bond (beta position to the phosphorus atom) and loss of phosphoethanolamine or phosphocholine. This technique makes possible the analysis of mixtures of intact phosphatidylethanolamine, phosphatidylcholine, 2-lysophosphatidylcholine, and sphingomyelin isolated from natural sources such as egg yolk or brain. Only minor and inexpensive modifications of a standard mass spectrometer are required.

A simple, sensitive, and practical method is described for determination of nitrite in egg, egg white, and egg yolk. Egg is deproteinized by adding a mixture of ammonium thiocyanate, mercuric chloride, and zinc acetate, and centrifuged. Nitrite in the supernate is converted to tetrazolophthalazine by reaction with hydralazine in acidic solution and then determined by gas-liquid chromatography with an electron-capture detector (GLC-ECD) and a column of OV-225 on Chromosorb W(HP). Nitrite concentrations from 5 to 50 ng/mL are calculated from peak height; the detection limit is 3 ng/mL extract. Recoveries from eggs, egg whites, and egg yolks ranged from 91.7 to 98.0%. The mean nitrite concentration in 50 egg samples was 0.04 ppm (0.01-0.11 ppm) with a detection limit of 4 ng nitrite/g.

A trial was conducted to assess the effects of choline and methionine supplementation of the diets of hens on phospholipid composition of egg yolk. By chemical analysis, the basal diet contained 16.6% protein, 1,041 parts per million (ppm) of choline, and .53% TSAA. The energy level was 2,899 kcal ME/kg diet, with no added fat. A rapid isocratic HPLC procedure using a Waters mu Bond-NH2 column (Waters Associates, Milford, MA) was developed to quantify phospholipid components. Analysis of egg samples at peak production (36 wk of age) showed significant (P less than .05) elevations in total phospholipids, phosphatidylcholine (PC), and the ratio of PC to phosphatidylethanolamine (PE), when choline was added at 500 or 1,000 ppm. Phosphatidylethanolamine, in contrast, showed a decline with choline supplementation. Methionine supplementation (125 to 250 ppm) also caused elevations in the total phospholipid composition of the egg yolk but had only modest effects on PC and PE. There was a significant (P less than .05) correlation between the yolk weight and total phospholipid concentration, PC, and the PC:PE ratio. There was a relationship between phospholipid content and weight of eggs when diets of laying hens were supplemented with choline.

Thyroxine (T4), 3,5,3'-triiodothyronine (T3) and 3,3',5-triiodothyronine (rT3) were determined in the yolk and white of the hen's egg and in the oocytes at various stages of development. For this purpose we have utilized the property of 0.08 N NaOH both to dilute the yolk or white and to extract and bind iodothyronines by strong alkaline Sephadex G-25. No iodothyronines were detected in the egg white. The total levels of T4 and T3/per 100 mg of yolk increased gradually with increased weight of oocytes weighing less than 6 g. Above this weight, levels of both iodothyronines were stable. The concentrations of T4 and T3 ranged from 0.6 to 1.0 ng and 150 to 230 pg/100 mg of yolk, respectively. The concentration of rT3 per 100 mg of yolk was independent of the weight of the oocytes and ranged between 10 and 100 pg/100 mg. The serum:yolk ratio oscillated between 2.62 and 1.15; 1.16 and 0.48; 0.11 and 0.15 in smallest and largest oocytes for T4, T3 and rT3, respectively. The perfusion experiment of the ovary indicates that all three iodothyronines can enter the ovary. The accumulation of iodothyronines by the ovary after 3 hr of incubation was as follows (in percentage of total radioactivity): T4, 35.85 +/- 2.94; T3, 26.73 +/- 2.97; rT3, 27.02 +/- 4.38. The highest accumulation of 125I-labelled iodothyronines per unit mass was seen in the oocytes of lowest size. The 3' or 5' deiodination of iodothyronines by the ovary, measured in the medium after 3 hr of perfusion, was negligible.

The activity of a pigeon adipose tissue hormone-sensitive triacylglycerol lipase preparation was increased from 2- to 5-fold by the presence of phosphatidylethanolamine in assays with three different methods of preparing triolein substrates. Phosphatidylethanolamine from egg yolk produced the greatest stimulation of lipase activity; the stimulation was concentration-dependent but was not time-dependent. A comparable increase in triacylglycerol lipase activity due to phosphatidylethanolamine was also observed with enzyme preparations from chicken and rat adipose tissue. Phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphatidic acid, cardiolipin, sphingomyelin, Triton X-100 and sodium dodecyl sulfate all inhibited enzyme activity. Phosphatidylethanolamine had no effect on acid lipase activity in the pigeon adipose tissue preparation. Preincubation of the pigeon adipose tissue lipase with ATP, cyclic AMP and protein kinase resulted in a 2.15-fold activation of hydrolase activity determined in the absence of phosphatidylethanolamine. In contrast, non-activated and protein kinase-activated forms of the lipase were characterized as having very nearly the same activity in assays with substrate preparations containing phosphatidylethanolamine. The phosphatidylethanolamine-dependent stimulation of lipase activity was characterized kinetically as being due to an increase in maximal velocity. The modulation of the adipose tissue hormone-sensitive lipase activity by phospholipids could be involved in the hormonal regulation of lipolysis.

The structure and functional significance of the yolk nucleus in Garra are described. The study shows that the yolk nucleus appears in the cytoplasm of the early perinucleolus stage of the oocyte. It is present as a deeply stained structure enclosed in a vesicle. It disappears in the yolk vesicle stage and vitellogenesis begins soon afterwards. This probably indicates that it plays a role in the initiation of vitellogenesis. When yolk formation starts, the yolk nucleus disappears; this also suggests that it is of functional significance in yolk synthesis.

An easily prepared and stable protein fraction from chick egg yolk promotes cell division (40 h generation time) and expression of procollagen (60% of total protein synthesis) in primary avian tendon cells in a serum-free medium. The activity of this yolk fraction (YF) is proteinaceous as reflected by its sensitivity to protease treatment. Yolk fraction is resolved into four major components on sodium dodecyl sulfate polyacrylamide gel electrophoresis with apparent molecular weights of 82,70,42,35 (X 10(-3)). Under nondenaturing conditions, YF runs as a mixture of high molecular weight aggregates on Sephacryl G-200. We postulate that the active part of YF could be the in ovo growth promoter for embryonic chick tendon cells.

The binding of Na+ and K+ to hen egg-yolk phosvitin has been studied by 23Na and 39K NMR. A transition in the binding behaviour of these cations is shown to accompany deprotonation of the phosphate groups on this highly charged protein. At lower pH the data are well described by a purely mass-action binding model, whereas at higher pH significant polyelectrolyte effects are apparent. From single ion as well as competition experiments K+ is shown to bind more strongly to phosvitin than does Na+. The temperature and magnetic field strength dependences of the 23Na and 39K relaxation rates provide a picture of phosvitin as a highly flexible macromolecule. This work demonstrates the potential of 39K NMR as a useful tool in the study of protein-cation interactions.

The addition of 100 p.p.m. of vanadium to a ration for White Leghorn laying hens caused a significant increase (p less than 0.01) in the egg shell thickness, but did not cause any significant change in the production, egg weight or egg ypok cholesterol content. The addition of 300 p.p.m. of vanadium caused a severe depression in the egg production which was the only symptom of vanadium toxicity to be observed. The addition of 50, 100, 200 or 300 p.p.m. vanadium to the ration of laying coturnix did not cause any significant change in egg production, egg weight, or egg yolk cholesterol content. The addition of the same levels of vanadium to one-day old male coturnix chicks did not cause any significant growth depression or mortality. We suggest that coturnix may be more resistant to vanadium toxicity than chickens.