Yolk Protein Research Articles

Physical and chemical quality of chicken eggs (Lohman brown strains) feed conventional feed with the addition of lemuru fish oil

This study aims to determine the quality of chicken eggs of the Lohman Brown has given fish oil in rations. The design used was a completely randomized design (CRD) with a total of 160 chickens with 4 treatments and 4 replications and each replication consisted of 10 chickens. P0: Ration without fish oil, P1: Ration using 0.2% fish oil, P2: Rations using 0.3% fish oil, P3: Rations using 0.4% fish oil. The feed used is composed of feed ingredients, namely corn, bran, concentrate, mineral, and fish flour. The variables observed included egg weight, egg white weight, egg yolk weight, shell thickness, shell weight, yolk color, Haugh units, yolk index, fat content, protein content, and cholesterol. The results showed that the use of fish oil of 0.2% in the ratio gave significantly different results (P<0.05) on egg weight, yolk weight, shell thickness, Haugh unit, or yolk index, while the results showed no significant difference (P>0.05) on white weight, shell weight, yolk color, fat content, protein content, cholesterol in eggs.

Vitellogenin uptake activity in the intestinal ducts of intraovarian embryos in a viviparous teleost Xenotoca eiseni

In the viviparous teleost species belonging to the family Goodeidae, intraovarian embryos absorb maternal supplements while they grow during the gestation period. They take up the components via trophotaeniae, a hindgut-derived placental structure. Our previous study using a goodeid species Xenotoca eiseni revealed that intraovarian embryos absorb the yolk protein vitellogenin (Vtg) via the trophotaenia. However, another group indicated yolk components accumulate in the intestinal lumen of X. eiseni embryos. Here, we investigated whether the intestinal duct is capable of protein uptake, as is the trophotaenia. Immunohistochemical studies indicated that endogenous vitellogenin is detected in the intestinal epithelial cells of the intraovarian embryo. Tracer analysis using FITC-Vtg also indicated that intestinal tissues can take up protein. The endocytosis-related genes expressed in trophotaenia were also detected in the intestinal tissues of the embryo. Lipid transporter genes which are not expressed in the trophotaenia were detected in the embryonic intestine. This evidence suggests that the intraovarian embryo of X. eiseni possesses two distinct sites for uptake of the maternal proteins. However, the presumed functions of the embryonic intestine and trophotaenia might be not identical. The study provides a new perspective on how mother-to-embryo matrotrophic interactions have changed in the evolution of viviparous teleosts.

Quality evaluation of table eggs under different rearing systems in China

Because of the impact of the COVID-19 pandemic, more and more people are choosing to buy food online, including eggs. Although this mode of shopping is very modern, many Chinese consumers lack scientific knowledge when selecting eggs. In this study, we used the multivariate statistical analysis and sensory analysis to evaluate and compare the qualities of online sale of free-range and cage eggs. How feeding conditions influence the quality of eggs and how physical characteristics influence the price of eggs were also studied in this work. Our research showed that there is a lack of scientific support for distinguish free-range eggs from cage eggs on the appearance, the color of the yolk does not represent the amount of protein in yolk which may actually be affected by fodders. Moreover, the nutritional quality of free-range eggs is no better than that of cage eggs. Sensory analysis showed that free-range eggs taste better, which is likely because of the higher yolk ratio. Multivariate linear regression analysis showed that Rearing systems, fodder type and yolk color have significant impact on the price (Price = 0.428 × Rearing system −0.235 × Fodder type + 0.191 × Yolk color).

Effect of Four Extraction Processes with Acetone-Ethanol Protocols on the Properties of Egg Yolk Phosphatidylcholine and the Structure of Residual Protein.

In this study, four acetone-ethanol protocols were employed to investigate the effect of extraction processes on the yield and purity of phosphatidylcholine (PC) from dried egg yolk powder and fresh liquid egg yolk, as well as the cholesterol distribution between the oil and PC fraction. Furthermore, the physicochemical (thermo-stability, fatty acid composition, and molecular structure) and emulsifying (zeta potential, particle size, EAI, ESI, and creaming index) properties of the final PC product were also examined. In addition, the structural characteristics of the egg yolk residual protein were highlighted to promote its application in food industries. The results showed that de-oiling with acetone prior to ethanol extraction can achieve high yield (19.92%) and purity (68.62%) of the PC product with low cholesterol content (< 0.12%). The extraction processes exhibited a significant impact on the emulsifying properties of the PC product. The creaming index of PC emulsions was higher than that of egg yolk powder emulsions with high protein concentration, suggesting that PC plays a critical role in the emulsifying stability of egg yolk protein dispersion. The structural characteristics of residual protein, including free sulfhydryl groups and primary, secondary, and ternary structures, showed considerable differentiation related to extraction processes. These findings provide a powerful tool for the dietary utilization of egg yolk PC and protein in future.

Improvement of egg internal quality of local ducks through star gooseberry leaf meal inclusion in ration.

The use of dried star gooseberry leaf extract (DSGLE) in rations and its effects on the egg internal quality of local ducks were examined. A total of 100 9-month-old local ducks weighing 1,406.25 ± 211.32 gm were randomly allocated into 5 treatments and 5 replicates in a completely randomized design. The birds were reared in 25 battery cages (4 birds each) and fed rations containing 0, 0.5%, 1.0%, 1.5%, and 2.0% DSGLE. Eggs of ducks fed DSGLE had significantly lower saturated fatty acid (SFA) (30.66%-32.53%) than those of control ducks (36.23%). Egg polyunsaturated fatty acids (PUFA) increased from 2.29% (control) to 2.61% (2.0% DSGLE) and 2.76% (1.5% DSGLE), while egg monounsaturated fatty acid (MUFA) contents were not significantly different. The fatty acids of the whole edible part of eggs (albumen + yolk) were composed mainly of MUFA (40.19%-44.34%), followed by SFA (30.66%-36.22%), and PUFA (2.29%-2.76%). Malondialdehyde contents were reduced from 6.07 to 4.92 µg/gm (19%) in egg yolk and from 1.50 to 0.62 µg/gm (59%) in egg white, and thiobarbituric acid reactive substances values of the eggs were reduced from 0.93 to 1.65 (77%). The egg cholesterol level of ducks fed 2% DSGLE (21.94 mg/gm) was about 28.5% lower than that of eggs from control ducks (30.67 mg/gm) of eggs of control ducks. The egg white and egg yolk protein contents (12.31% and 16.35%) of treated ducks were lower than those in the control group (13.58% and 17.47%). The inclusion of SGLE in rations could be used to produce healthy duck eggs with no oxidative damage.

Preparation of Caenorhabditis elegans for Scoring of Muscle-derived Exophers.

Utilizingresources available from the mother's body to guarantee healthy offspring growth is the fundamental reproductive strategy. Recently, we showed that a class of the largest extracellular vesicles known as exophers, which are responsible for the removal of neurotoxic components from neurons ( Melentijevic et al., 2017 ) and damaged mitochondria from cardiomyocytes (Nicolás-Ávila et al., 2020), are released by the Caenorhabditis elegans hermaphrodite body wall muscles (BWM), to support embryonic growth ( Turek et al., 2021 ). Employing worms expressing fluorescent reporters in BWM cells, we found that exopher formation (exophergenesis) is sex-specific and fertility-dependent. Moreover, exophergenesis is regulated by the developing embryo in utero, and exophers serve as transporters for muscle-generated yolk proteins, which can be used to nourish the next generation. Given the specific regulation of muscular exophergenesis, and the fact that muscle-generated exophers are much larger than neuronal ones and have different targeting, their identification and quantification required a modified approach from that designed for neuronal-derived exophers ( Arnold et al., 2020 ). Here, we present a methodology for assessing and quantifying muscle-derived exophers that can be easily extended to determine their function and regulation in various biological contexts. Graphical abstract.

Novel extraction technologies and potential applications of egg yolk proteins.

The high nutritional value and diverse functional properties of egg yolk proteins have led to its widespread use in the fields of food, medicine, and cosmetics. Various extraction methods have been reported to obtain the proteins from egg yolk, however, their utilization is limited due to the relatively low extraction efficiency and/or toxic solvents involved. Several simpler and greener technologies, especially physical fields (ultrasound), have been successfully developed to improve the extraction efficiency. The egg yolk proteins may exert multiple biological activities, enabling them to be a promising tool in improve human health and wellbeing, such as anti-obesity, anti-atherosclerosis, anti-osteoporosis, diagnosis and therapy for SARS-CoV-2 infections. This article summarizes the novel extraction technologies and latest applications of the egg yolk proteins in the recent 5years, which should stimulate their utilization as health-promoting functional ingredients in foods and other commercial products.

Extraction and determination of Iraqi boiled Egg Yolk constituents, and characterization of Lecithin.

This study aimed to extract, determine the Iraqi boiled Egg Yolk constituents and characterize the lecithin. The moisture content of the heated egg yolks was (54%). Egg Yolk protein was extracted using absolute ethanol and the calculated protein percent was (31.31%). The remaining egg yolk was deoiled with acetone using AOCS Official Method Ja 4-46 [13], and the calculated oil percent was (6.72 %). Egg Yolk remaining protein was extracted using chloroform / methanol mixture and the calculated remaining protein percent was (5.7%). Finally Lecithin content was (10.29%). Pure Lecithin was characterized by FT-IR (Shimadzu FT-IR Spectrometer – 30 000:1/ IRAff), U.V-Vis. Analysis (U.V-Vis. Spectrophotometer, Shimadzu 1800), and Powder X-ray diffraction (XRD – 6000 Shimadzu)..

Egg Quality of Italian Local Chicken Breeds: II. Composition and Predictive Ability of VIS-Near-InfraRed Spectroscopy.

The aims of the present study were to characterize egg composition and develop VIS-Near-infrared spectroscopy (VIS-NIR) models for its predictions in Italian local chicken breeds, namely Padovana Camosciata, Padovana Dorata, Polverara Bianca, Polverara Nera, Pepoi, Ermellinata di Rovigo, Robusta Maculata and Robusta Lionata. Hens were reared in a single conservation center under the same environmental and management conditions. A total of 200 samples (25 samples per breed, two eggs/sample) were analyzed for the composition of albumen and yolk. Prediction models for these traits were developed on both fresh and freeze-dried samples. Eggs of Polverara Nera and Polverara Bianca differed from eggs of the other breeds (p < 0.05) in terms of the greatest moisture content (90.06 ± 1.23% and 89.57 ± 1.31%, respectively) and the lowest protein content (8.34 ± 1.27% and 8.81 ± 1.27%) in the albumen on wet basis. As regards the yolk, Robusta Maculata and Robusta Lionata differed (p < 0.05) from the other breeds, having lower protein content (15.62 ± 1.13% and 15.21 ± 0.63%, respectively) and greater lipid content (34.11 ± 1.12% and 35.30 ± 0.98%) on wet basis. Eggs of Pepoi had greater cholesterol content (1406.39 ± 82.34 mg/100 g) on wet basis compared with Padovana Camosciata, Polverara Bianca and Robusta Maculata (p < 0.05). Spectral data were collected in reflectance mode in the VIS-NIR range (400 to 2500 nm) using DS2500 (Foss, Hillerød, Denmark) on fresh and freeze-dried samples. Models were developed through partial least-squares regression on untreated and pre-treated spectra independently for yolk and albumen, and using several combinations of scattering corrections and mathematical treatments. The predictive ability of the models developed for each compound was evaluated through the coefficient of determination (R2cv), standard error of prediction (SEcv) and the ratio of performance to deviation (RPDcv) in cross-validation. Prediction models performed better for freeze-dried than fresh albumen and yolk. In particular, for the albumen the performance of models using freeze-dried eggs was excellent (R2cv ≥ 0.91), and for yolk it was suitable for the prediction of protein content and dry matter. Good performances of prediction were observed in yolk for dry matter (R2cv = 0.85), lipids and cholesterol (R2cv = 0.74). Overall, the results support the potential of infrared technology to predict the composition of eggs from local hens. Prediction models for proteins, dry matter and lipids of freeze-dried yolk could be used for labelling purposes to promote local breeds through the valorization of nutritional aspects.

An Efficient Processing Strategy to Improve the Flavor Profile of Egg Yolk: Ozone-Mediated Oxidation.

This study investigated the effect of ozone treatment on egg yolk volatiles and fatty acids. The composition and content of volatile substances and the fatty acid content of the egg yolk were changed significantly after ozonation. With proper ozone treatment (30 min), the aldehyde content in the egg yolk increased from 78.08% to 94.63%, and the relative content of dibutyl amine decreased from 1.50% to 0.00%. There were no significant differences among the types of fatty acids in the egg yolks after being treated with ozone, but there were differences in their relative contents. The results of SDS-PAGE showed no significant difference in yolk protein composition and contents among the groups. SEM results showed that moderate ozone treatment (20 min and 30 min) led to a regular and dense network structure of egg yolk. These results provided a theoretical basis for expanding the application of ozone technology in the egg yolk processing industry.

Investigating the role of glycoprotein hormone GPA2/GPB5 signaling in reproduction in adult female Rhodnius prolixus.

Glycoprotein hormones are essential for regulating various physiological activities in vertebrates and invertebrates. In vertebrates, the classical glycoprotein hormones include follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH) and chorionic gonadotropin (CG), which have crucial roles in growth, development, metabolism, and reproduction. In female mammals, FSH stimulates egg production in the ovaries, whereas LH and CG act as the triggers for follicular ovulation. The more recently discovered heterodimeric glycoprotein hormone GPA2/GPB5 (called thyrostimulin in vertebrates) is suggested to be involved in reproductive processes in arthropods. Here, we focus on understanding the role of GPA2/GPB5 and its receptor, LGR1, in the reproductive success of adult female Rhodnius prolixus, a vector of Chagas disease. qPCR was used to monitor the expression of GPA2 and GPB5 transcripts and their receptor in different tissues. Immunohistochemistry was used to show the distribution of GPB5 in the nervous system and reproductive system, and RNA interference was used to disrupt the glycoprotein hormone signaling pathway. Both subunit transcripts, GPA2 and GPB5, are present in a variety of tissues, with the greatest expression in the central nervous system; whereas the LGR1 transcript is present in peripheral tissues, including the fat body and the reproductive system of adult females. In the adult female, GPB5-like immunoreactive axonal projections are present in the trunk nerves extending onto the reproductive tissues, with processes overlaying the ovaries, oviducts, spermatheca, and bursa, indicating the possibility of neural control by neurons containing GPA2/GPB5. In addition, GPB5-like immunostaining is present in muscles encircling the ovarioles, and in the cytoplasm of trophocytes (nurse cells) located in the tropharium. GPB5-like immunoreactive processes and blebs are also localized to the previtellogenic follicles, suggesting an involvement of this glycoprotein hormone signaling in oocyte development. LGR1 transcript expression increases in the adult female reproductive system post-feeding, a stimulus that initiates reproductive development, adding further support to an involvement in reproduction. We have investigated the effect of LGR1 downregulation on reproductive processes, monitoring the number and the quality of eggs laid, hatching ratio, and production of vitellogenin (Vg), the major yolk protein for developing eggs. Downregulation of LGR1 leads to increases in transcript expression of vitellogenin, RhoprVg1, in the fat body and the vitellogenin receptor, RhoprVgR, in the ovaries. Total protein in the fat body and hemolymph of dsLGR1-injected insects increased compared to controls and associated with this effect was a significant increase in vitellogenin in these tissues. dsLGR1-injection leads to accelerated oogenesis, an increase in the number of eggs produced and laid, an increase in egg size and a reduction in hatching rate. Our results indicate that GPA2/GPB5 signaling acts to delay egg production in adult female R. prolixus.

Interaction between the parasitic barnacle Polyascus planus (Cirripedia: Rhizocephala) and its brachyuran host Metopograpsus thukuhar during the development of the externa of the parasite: Control of the gonadal development and vitellogenin synthesis of the host

Developmental profile of the female reproductive apparatus (the externa) of Polyascus planus parasitizing the thukuhar shore-crab Metopograpsus thukuhar is described. The development is divided into 4 stages, which are named based on the distinct color of the externa at each stage. The effects of parasitism on the gonad and hepatopancreas of the host were then examined. The ovary was heavily infiltrated by the rootlet of the parasite, with the oocytes being arrested at the pre-vitellogenic state, whereas the testis, not being infiltrated, still contained abundant amounts of spermatozoa. The hepatopancreas of the hosts of both sexes was heavily infiltrated by the rootlets. Regarding the synthesis of vitellogenin (Vg), the hemolymph precursor of the major yolk protein (vitellin, Vn), expression of host Vg gene was detected in the ovary and hepatopancreas of both non-parasitized and parasitized females, and, importantly, its expression found to be induced in the hepatopancreas of parasitized males. Furthermore, results of quantitative gene expression assays showed that expression levels of the host Vg in the ovary and hepatopancreas did not change significantly among the various parasitization status (i.e., host bearing externa of different developmental stages), nor did those of the parasite Vg in the externa among the developmental stage of the externa. The Vg expression levels in the hepatopancreas of parasitized males and in the externa were however negatively correlated. Finally, analysis of tryptic peptide fragments derived from hemolymph proteins of high molecular weight in the parasitized males confirmed the induction of synthesis of the host Vg, whereas analysis of externa proteins of similar molecular weight revealed that Vg of both host and parasite origins contributes to the formation of parasite Vn. The combined results indicate that the parasitized hosts, regardless of sex, synthesize Vg for the ovarian maturation of the parasite, to which Vg of parasite origin also contributes. Discussion is also made with regard to the strategy the parasite adopts toward hosts of different sexes. The profile of the development of externa established would serve as a temporal framework against which studies of host/parasite interaction can be conducted in a developmental context.

Transcriptome-wide analysis of pseudouridylation in Drosophila melanogaster.

Pseudouridine (Psi) is one of the most frequent post-transcriptional modification of RNA. Enzymatic Psi modification occurs on rRNA, snRNA, snoRNA, tRNA, and non-coding RNA and has recently been discovered on mRNA. Transcriptome-wide detection of Psi (Psi-seq) has yet to be performed for the widely studied model organism Drosophila melanogaster. Here, we optimized Psi-seq analysis for this species and have identified thousands of Psi modifications throughout the female fly head transcriptome. We find that Psi is widespread on both cellular and mitochondrial rRNAs. In addition, more than a thousand Psi sites were found on mRNAs. When pseudouridylated, mRNAs frequently had many Psi sites. Many mRNA Psi sites are present in genes encoding for ribosomal proteins, and many are found in mitochondrial encoded RNAs, further implicating the importance of pseudouridylation for ribosome and mitochondrial function. The 7SLRNA of the signal recognition particle is the non-coding RNA most enriched for Psi. The 3 mRNAs most enriched for Psi encode highly expressed yolk proteins (Yp1, Yp2, and Yp3). By comparing the pseudouridine profiles in the RluA-2 mutant and the w1118 control genotype, we identified Psi sites that were missing in the mutant RNA as potential RluA-2 targets. Finally, differential gene expression analysis of the mutant transcriptome indicates a major impact of loss of RluA-2 on the ribosome and translational machinery.

The Molecular Docking and Inhibition Kinetics of Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Soft-Shelled Turtle Yolk

The soft-shelled turtle yolk (SSTY) protein hydrolysate contains a potential source of bioactive peptides. Our previous study found that five SSTY peptides (WLQL, LPSW, LPLF, VPGLAL and LVGLPL) showed moderate to high dipeptidyl peptidase IV (DPP-IV) inhibitory activities. This study further investigated their angiotensin-I-converting enzyme (ACE) inhibitory activity. Consequently, WLQL was identified as the most potent ACE inhibitory peptide with a remarkably low IC50 value (16.87 ± 0.54 µM). The Lineweaver–Burk plot analysis was performed for the characterization of the peptide’s inhibition mode and the inhibition kinetics was rationalized using the molecular docking simulation. The result revealed that WLQL would dock into the S1 pockets of ACE, while LPSW interacted with ACE’s secondary binding site. Further evaluation of the peptides’ stability against ACE involved a pre-incubation experiment. After 3 h of pre-incubation with ACE, the four peptides were hydrolyzed into smaller fragments with varying degrees, suggesting that they are substrate-type inhibitors. In contrast, LVGLPL can tolerate hydrolysis by ACE and act as a true inhibitor.

Effects of CaCl2 on salting kinetics, water migration, aggregation behavior and protein structure in rapidly salted separated egg yolks

Salted egg yolks are valued by consumers for their delicious taste good processing characteristics. To improve the quality of rapidly salted separated egg yolks, we compared changes in the salting kinetics, textural properties, water migration, protein aggregation and structure of salted egg yolks in the presence or absence of CaCl2 for 24 h. CaCl2 increased the mass transfer driving force and diffusion coefficient during the salting process; as a result, the salted egg yolks exhibited increased hardness and decreased springiness and cohesiveness. Through low field nuclear magnetic resonance (LF NMR), it was confirmed that CaCl2 promoted the precipitation of lipids and the dehydration of egg yolk. Furthermore, CaCl2 promoted the bulk aggregation of proteins. The analyses of protein structures showed that the contents of β-sheets and irregular curls in CaCl2-salted egg yolk protein increased, while the contents of α-helices and β-turns decreased. CaCl2 affected the microenvironment of tryptophan residues and embedded these residues, enhancing protein aggregation. Based on the comprehensive information obtained in this study, adding CaCl2 to the salting solution improved the degree of protein polymerization in egg yolk; thus, this method might be used to improve the quality of egg yolks separated by salt.

Effects of ethanol treatment on the physicochemical properties, microstructure and protein structures of egg yolk gels

The aim of this study was to investigate the effect of ethanol treatment on the properties of egg yolk gels (EYG). The hardness of EYG showed an increasing trend, and the changes in free sulfhydryl groups manifested that ethanol treatment facilitated the formation of disulfide bonds. Environment scanning electron microscopy revealed that the degree of protein aggregation increased. Low-field nuclear magnetic resonance results indicated that ethanol treatment promoted the conversion of immobile water or lipids to free water or lipids. Moreover, the increase in the absolute of zeta potential was accompanied by the decrease in surface hydrophobicity, and the secondary structure of native egg yolk (EY) proteins underwent changes with ethanol treatment. Overall, these results demonstrated that ethanol treatment induced the structural unfolding and aggregation of EY proteins, and facilitated the better stability of the gel structures. The impact of the ethanol on the EYG increased with the concentration.

Impact of JH Signaling on Reproductive Physiology of the Classical Insect Model, Rhodnius prolixus.

In adult females of several insect species, juvenile hormones (JHs) act as gonadotrophic hormones, regulating egg production. JH binds to its nuclear receptor, Methoprene tolerant (Met), triggering its dimerization with the protein Taiman (Tai). The resulting active complex induces transcription of JH response genes, such as Krüppel homolog 1 (Kr-h1). In this study we report for the first time the participation of the isoform JH III skipped bisepoxide (JHSB3) and its signaling pathway in the reproductive fitness of the classical insect model Rhodnius prolixus. The topical application of synthetic JHSB3 increases transcript and protein expression of yolk protein precursors (YPPs), mainly by the fat body but also by the ovaries, the second source of YPPs. These results are also confirmed by ex vivo assays. In contrast, when the JH signaling cascade is impaired via RNA interference by downregulating RhoprMet and RhoprTai mRNA, egg production is inhibited. Although RhoprKr-h1 transcript expression is highly dependent on JHSB3 signaling, it is not involved in egg production but rather in successful hatching. This research contributes missing pieces of JH action in the insect model in which JH was first postulated almost 100 years ago.

Identification of Vitellogenin 1 Potentially Related to Reproduction in the Cephalopod, Sepiella japonica

Vitellogenin (Vg) is the precursor of yolk protein, which plays an important role in the reproduction and development of oviparous animals. In this study, vitellogenin1 (Vg1) from Sepiella japonica was cloned and characterized, and its potential function in ovarian development was investigated. The full-length cDNAs of Vg1 was 5853 base pair (bp) that encoded 748 amino acids. Sequence analysis revealed that the overall protein sequence of Vg1 shared 66% identity with that of Uroteuthis edulis. Analyses with quantitative reverse transcription polymerase chain reaction (RT-qPCR) showed that the highest expression of Vg1 occurred in the ovary. As ovary developed, the expression of Vg1 increased in both ovary and liver from oogonia phase (I) to interstitial growth phase (III), and reached to the peak value at stage III. In addition, we examined the effects of Gonadotropin-releasing hormone (GnRH) on Vg1 expression in the ovary and liver were examined. The data showed that GnRH increased mRNA expression of Vg1, indicating that exogenous GnRH initially affected Vg1 expression and then influenced ovarian maturation. This study suggests that Vg1 might be involved in ovarian development in cephalopods.

Investigating the loss of major yolk proteins during the processing of sea cucumber (Apostichopus japonicus) using an MRM-based targeted proteomics strategy

Major yolk proteins (MYPs), one class of the main abundant proteins in sea cucumber body wall, seem to garner more attention in recent years. Herein, a method using multiple reactions monitoring mass spectrometry (MRM-MS) was deliberatively developed to perform quantification analysis of three MYPs, i.e. BAH79576.1, BAH79577.1 and PIK45784.1. Contents of MYPs in body wall of fresh and dried sea cucumbers as well as in waste liquid of boiling and steaming were determined using their corresponding signature peptides of VDEFTGIVGSLR, KLDMYPPPLAR, LDMYPPPLAR, and SGHGEVMFVDSK. The loss of MYPs in the processing of sea cucumbers was directly verified by quantitation data of MYPs in sea cucumber body wall and the waste liquids. This study not only evidenced the loss of MYPs during the processing of sea cucumbers, but also implicated the potential of recycling MYPs from the processing waste water, providing helpful suggestions in maximizing the value of sea cucumbers.

Vitellogenin Ab structure of the amazonian Arapaima gigas

The vitellogenin is composed by polypeptides that are precursors of egg yolk proteins that provides embryo and larvae nutrition. The mRNA encoding for vitellogenin Ab (Vtg-Ab; 4,536 bp long and 1,512 amino acids) were obtained by RNA-Seq library sequencing of pirarucu gonads. The Vtg-Ab sequences had high homology with Vtgs of other three teleosts species of the order Osteoglossiformes. The transcript of ovarian Vtg was identified based on structural criteria, and so we classify the Vtg of pirarucu as Vtg-Ab due to the truncated or shortened phosvitin (N-terminal end) and phosvitinless domain (C-terminal end). The Vtg-Ab of pirarucu present two major deletions with 133 amino acids in the Lipovitellin I domain and 89 amino acids in the truncated or shortened Phosvitin domain, both located in the N-terminal end region. The three-dimensional (3-D) structure Vtg-Ab protein shows the presence of a typical 4α-helices bundle protein that runs in anti-parallel. In general, the characterization of Vtg-Ab may be the useful elucidation of the hormonal regulation of vitellogenesis and improve the production of pirarucu for broodstock management in aquaculture and preparation of Vtg antibody production (species-specific) for sex identification.