Search results for "Egg Yolk"
showing 10 items of 10 documents
Geographical trends in the yolk carotenoid composition of the pied flycatcher (Ficedula hypoleuca).
2010
Carotenoids in the egg yolks of birds are considered to be important antioxidants and immune stimulants during the rapid growth of embryos. Yolk carotenoid composition is strongly affected by the carotenoid composition of the female’s diet at the time of egg formation. Spatial and temporal differences in carotenoid availability may thus be reflected in yolk concentrations. To assess whether yolk carotenoid concentrations or carotenoid profiles show any large-scale geographical trends or differences among habitats, we collected yolk samples from 16 European populations of the pied flycatcher, Ficedula hypoleuca. We found that the concentrations and proportions of lutein and some other xantho…
Evolution of yolk androgens in birds: development, coloniality and sexual dichromatism
2007
18 pages; International audience; Current theory recognizes the adaptive value of maternal effects in shaping offspring phenotypes in response to selective pressures and vindicates the value of these traits in fostering adaptation and speciation. Yolk androgens in birds are a relatively well-known maternal effect and have been linked to adaptations related to development, coloniality life, and sexual selection. We tested whether interspecific patterns of yolk androgen levels (androstenedione and testosterone) were related to interspecific variation in development, sexual selection, and coloniality. First, we found no relationship between androgen levels and duration of development as reflec…
Is maternal thyroid hormone deposition subject to a trade-off between self and egg because of iodine?
2021
ABSTRACT Maternal hormones constitute a key signalling pathway for mothers to shape offspring phenotype and fitness. Thyroid hormones (THs; triiodothyronine, T3; and thyroxine, T4) are metabolic hormones known to play crucial roles in embryonic development and survival in all vertebrates. During early developmental stages, embryos exclusively rely on exposure to maternal THs, and maternal hypothyroidism can cause severe embryonic maldevelopment. The TH molecule includes iodine, an element that cannot be synthesised by the organism. Therefore, TH production may become costly when environmental iodine availability is low. This may yield a trade-off for breeding females between allocating the …
The impact of model peptides on structural and dynamic properties of egg yolk lecithin liposomes - experimental and DFT studies.
2015
Electron spin resonance (ESR), 1H-NMR, voltage and resistance experiments were performed to explore structural and dynamic changes of Egg Yolk Lecithin (EYL) bilayer upon addition of model peptides. Two of them are phenylalanine (Phe) derivatives, Ac-Phe-NHMe (1) and Ac-Phe-NMe2 (2), and the third one, Ac-(Z)-ΔPhe-NMe2 (3), is a derivative of (Z)-α,β-dehydrophenylalanine. The ESR results revealed that all compounds reduced the fluidity of liposome's membrane, and the highest activity was observed for compound 2 with N-methylated C-terminal amide bond (Ac-Phe-NMe2). This compound, being the most hydrophobic, penetrates easily through biological membranes. This was also observed in voltage an…
Experimental and theoretical NMR studies of interaction between phenylalanine derivative and egg yolk lecithin
2014
The interaction of phenylalanine diamide (Ac-Phe-NHMe) with egg yolk lecithin (EYL) in chloroform was studied by 1H and 13C NMR. Six complexes EYL–Ac-Phe-NHMe, stabilized by N–H···O or/and C–H···O hydrogen bonds, were optimized at M06-2X/6-31G(d,p) level. The assignment of EYL and Ac-Phe-NHMe NMR signals was supported using GIAO (gauge including atomic orbital) NMR calculations at VSXC and B3LYP level of theory combined with STO-3Gmag basis set. Results of our study indicate that the interaction of peptides with lecithin occurs mainly in the polar ‘head’ of the lecithin. Additionally, the most probable lecithin site of H-bond interaction with Ac-Phe-NHMe is the negatively charged oxygen in …
ESR study of the liposome membrane physical parameters in the heating-cooling cycles.
1998
Abstract Changes of dynamic and structural parameters of egg yolk lecithin (EYL) liposome membranes in the heating-cooling cycles have been studied using the E S R spin probe method. The investigations were conducted in the range of temperatures from -18 °C to +60 °C. It has been found that in the range of temperatures -15 °C to +45 °C in both the heating and the cooling run the spectroscopic parameters changed practically along the same curve (reversible changes). However, after exceeding this range of temperatures one of the parameters (partition coefficient of the spin probe 2,2,6,6 -tetramethylpiperidine -1-oxyl; TEMPO) changed along a closed curve, showing the phenomenon of thermal h…
Prenatal androgen exposure modulates cellular and humoral immune function of black-headed gull chicks
2005
Avian eggs contain considerable amounts of maternal yolk androgens, which have been shown to beneficially influence the physiology and behaviour of the chick. As androgens may suppress immune functions, they may also entail costs for the chick. This is particularly relevant for colonial species, such as the black-headed gull (Larus ridibundus), in which the aggregation of large numbers of birds during the breeding season enhances the risk of infectious diseases for the hatching chick.To test the effect of maternal yolk androgens on the chick's immune function, we experimentally manipulated, in a field study, yolk androgen levels within the physiological range by in ovo injection of either a…
Tin compounds interaction with membranes of egg lecithin liposomes.
2007
This work is a continuation of earlier research concerning the influence of tin compounds on the dynamic properties of liposome membranes produced with lecithin hen egg yolks (EYL). The experiments were carried out at room temperature (about 25 ∞C). Four tin compounds were chosen, including three organic ones, (CH3)4Sn, (C2H5)4Sn and (C3H7)3SnCl, and one inorganic, SnCl2. The investigated compounds were admixed to water dispersions of liposomes. The content of the admixture changed within the range 0 mol-% to 11mol-% in proportion to EYL. Two spin probes were used in the experiment: 2,2,6,6-tetramethylpiperidine- 1-oxyl (TEMPO) and 2-ethyl-2-(15-methoxy-15-oxopentadecyl)-4,4-dimethyl-3-oxaz…
Bimodal Effect of Amphiphilic Biocide Concentrations on Fluidity of Lipid Membranes
1996
Abstract Using the spin label method (ESR) it has been shown that biologically active, amphiphilic compounds (quaternary ammonium salts -AS) containing polar heads with single and double positive charge caused, at low concentrations, decrease fluidity of liposome membranes formed with egg yolk lecithin (EYL). At higher concentrations an increase in fluidity was observed. With compounds having a single positive charge minimum fluidity of membrane structure occurs in the range of 1 to 3%, with compounds containing double positive charge -in the range of 4 -6 % . That effect does not depend on polar head size and length of alkyl chains of the AS used. Analysis of the electrostatic interaction …
Production of an egg yolk antibody against Parietaria judaica 2 allergen
2009
Specific antibodies are essential tools for studying proteins as well as for diagnostic research in biomedicine. The egg yolk of immunized chicken is an inexpensive source of high-quality polyclonal antibodies. The 12-kDa Parietaria judaica 2 allergen was expressed as a fusion protein and was used to immunize Leghorn chickens. In this paper, we show, using 2-dimensional gel electrophoresis and immunoblotting, that chicken antibodies raised against a recombinant allergen can be used to recognize similar proteins from a pollen raw extract. Allergen identity was confirmed by nanoLC-nanospray-tandem mass spectrometry analysis. Our data demonstrate for the first time that a synergistic combinati…