yolkin

Yolkin is a polypeptide complex isolated from hen egg yolk that exhibits immunomodulating properties. The aim of the present study was to determine whether in-ovo-delivered yolkin affects leukocyte populations and cytokine levels in broiler chickens. The experiment was carried out on eggs from Ross 308 broiler breeder birds. Yolkin was administered in ovo on the 18th day of incubation, once, at the following three doses: 1, 10, or 100 µg/egg. The immunological parameters were assessed in 1-, 7-, 14-, 21-, 28-, 35-, and 42-day-old birds kept under farming conditions and routinely vaccinated...

Vitellogenin (Vt) is considered the primary protein precursor of egg yolk, serving as a source of protein- and lipid-rich nutrients for the developing embryo. However, recent research has revealed that the functions of Vt and Vt-derived polypeptides, such as yolkin (Y) and yolk glycopeptide 40 (YGP40), extend beyond their nutritional roles as a source of amino acids. Emerging evidence has demonstrated that both Y and YGP40 possess immunomodulatory properties and can contribute to host immune defenses. Additionally, Y polypeptides have been shown to exhibit neuroprotective activity, participating in the modulation of neurons' survival and activity, inhibiting neurodegeneration processes, and improving cognitive functions in rats...

Food-derived bioactive peptides able to regulate neuronal function have been intensively searched and studied for their potential therapeutic application. Our previous study showed that a polypeptide complex yolkin, isolated from hen egg yolk as a fraction accompanying immunoglobulin Y (IgY), improved memory and cognitive functions in rats. However, the mechanism activated by the yolkin is not explained. The goal of the present study was to examine what molecular mechanism regulating brain-derived neurotrophic factor (BDNF) expression is activated by the yolkin complex, using in vitro models of PC12 cell line and fetal rat hippocampal cell line H19-7...

Ageing is accompanied by the inevitable changes in the function of the immune system. It provides increased susceptibility to chronic infections that have a negative impact on the quality of life of older people. Therefore, rejuvenating the aged immunity has become an important research and therapeutic goal. Yolkin, a polypeptide complex isolated from hen egg yolks, possesses immunoregulatory and neuroprotective activity. Considering that macrophages play a key role in pathogen recognition and antigen presentation, we evaluated the impact of yolkin on the phenotype and function of mouse bone marrow-derived macrophages of the BMDM cell line...

The aim of this research was to analyze the heterologous expression, purification, and immunoregulatory activity of recombinant YGP40 (rYGP40), the potential precursor of the yolkin peptide complex. The ygp40 coding sequence was codon optimized, successfully expressed in the E. coli system, and purified from inclusion bodies with a yield of about 1.1 mg/L of culture. This study showed that the protein exhibits immunomodulatory activity, expressed by the stimulation of TNF-α and IL-10 production and nitric oxide induction at a level comparable to that of the natural yolkin peptide complex obtained by other authors from hen egg yolk...

The results of our research have proven that yolkin preparations isolated from eggs of different bird species show a high similarity in polypeptide composition. Despite the small differences in protein patterns, all of yolkin preparations showed also strong immunomodulatory activity, comparable with yolkin obtained previously from hen egg yolk. It can therefore be deducted that the presence of this polypeptide complex in the egg is not accidental and performs an important biological function for developing embryo...

Yolkin is a product of proteolytic degradation of vitellogenin, a protein contained in eggs' yolk, with already described procognitive properties. Here, we investigated effects of yolkin on the humoral and cellular immune response in mice, phenotype of cells from lymphoid organs and function of innate immunity cells. In vitro studies included effects of yolkin on mitogen-induced thymocyte proliferation, percentage of CD19 cells in bone marrow cells culture, expression of signaling molecules in Jurkat cells, interleukin 2 receptor (IL-2R) subunits in WEHI 231 cells and susceptibility of these cells to anti-Ig-induced cell death...

A large number of bioactive peptides isolated from natural sources are known to play important physiological roles in the human body. It is possible to use these as alternative therapy agents. One example is yolkin which can be useful as a food supplement, a natural therapeutic agent for preventing and treating cognitive disorders of various origins, preferably in patients with unsatisfactory responses to known therapies. A new simple method of isolation of yolkin based on precipitation with ethanol or acetone was developed...

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The study aimed to assess the effect of the polypeptide Y complex (Yolkin), isolated from chicken egg yolk, on behavioural and cognitive functions. It also aimed to compare this activity with colostrum-derived substances (Colostrinin, Coloco), which have a confirmed impact on learning and memory. In the study, the effect of Yolkin, administered to rats of different ages, who performed various tasks involving spatial and episodic memory, motor functions and exploratory behavior, was assessed. The experiment was carried out in rats which were 6 and 12 months old...

In the hen immune system the egg content plays as significant a role in the development of the chick as colostrum does in newborn mammals. One of the most important proteins in this system seems to be the main yolk immunoglobulin IgY. It has been shown that IgY is accompanied by an immunostimulatory polypeptide complex named yolkin. In this report the biological activities of yolkin separated by means of four different procedures are presented. It was shown that yolkin acts as an inducer rather than a modulator of cytokine and nitric oxide release, and does not participate in the protection of cells against destructive effects of reactive oxygen species...

The protein mixture of cytokine-inducing activity accompanying chicken immunoglobulin Y, named yolkin, consists of several peptides of molecular weight (MW) ranging from over 1 to 35 kDa. Yolkin and its constituent peptides were found to be efficient inducers of interleukin (IL)-1β, IL-6 and IL-10 secretion. N-terminal amino acid sequences of eight of the electrophoretically purified yolkin constituents revealed that all of them are homological to some fragments of the C-terminal domain of vitellogenin II...

Immunity transfer from a mother to the newborn does not depend exclusively on immunoglobulins. Peptides, which are characterized by immunoregulatory properties that accompany IgG(2), known as proline-rich polypeptide complex (PRP), have been discovered for the first time in ovine colostrum. In this report we present new data showing that some immunoregulatory peptides associated with the main immunoglobulin class, IgY, are also present in the avian immune system. Cytokine-inducing activity of particular fractions obtained from ovine colostrum, IgG+ (IgG(2) containing PRP), IgG- (IgG(2) free of PRP), and purified PRP, was compared with that of crude egg yolk IgY (IgY+), additionally purified egg yolk IgY (IgY-), and polypeptides accompanying IgY named Yolkin (Y), using an ex vivo model of whole human blood cells...

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