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ABSTRACT: Egg yolk (EY) can be divided into yolk granules (EYG) and yolk plasma (EYP) after water dilution and centrifugation. EYP had a significantly higher lipid content and is predominantly in the form of low-density lipoprotein (LDL) while EYG has a higher protein content. In order to explore the nutritional differences between EY, EYP and EYG, quantitative metabolomic analysis was carried out by ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS). The results showed that a total of 588 small molecule metabolites were identified, mainly glycerol phospholipids (51.59–66.46%), coenzymes, and vitamins (1.21–1.84%). A quantitative comparison showed that amino acids and their metabolites were the most representative metabolites of differential abundance in the contrast of EY and EYG, EYP and EYG. Carbohydrates and their metabolites were the representative metabolites of differential abundance between EY and EYP. The study provided important information for understanding the metabolic composition of EY, EYG, and EYP, as well as providing a reference for utilizing the whole egg.

Background and Objectives: The head louse Pediculus humanus capitis is a cosmopolitan ectoparasite that causes pediculosis. In the study of human lice, little research focuses on embryonic development. Currently, external markers of embryonic development represent a new approach in the evaluation of ovicidal drugs. The objective of this work was to update the morphology of embryonic development and propose novel external markers to differentiate between early, medium, or late P. h. capitis eggs. Methods: Using stereoscopic light microscopy, we describe the morphological characteristics of P. h. capitis eggs with a special focus on embryonic development. Results: The morphological analysis of the eggs revealed the presence of an operculum with ten aeropyles, although no micropyles were observed. For the first time, the presence of defective eggs that were non-viable due to the apparent absence of yolk granules was documented. The early eggs presented yolk granules and developing germ bands, while the medium eggs presented an embryonic rudiment and the outlines of the eyes and limbs. In late eggs, the head with eyes and antennae, the thorax with three pairs of legs, and the abdomen with six pairs of spiracles were observed as formed structures. At the end of this stage, the embryos acquired the morphology of the nymph I stage. Conclusion: We propose novel biomarkers (e.g., the presence of spiracles and antennae, the proportion of the egg occupied by the embryo) to facilitate the differentiation between the developmental stages. The updated morphological characteristics of P. h. capitis eggs facilitate the standardization of toxicological tests in the quest for ovicidal drugs. [ABSTRACT FROM AUTHOR]

Egg yolk granules (EYGs) are water-insoluble components of egg yolk that are rich in protein and phospholipids. Improving the solubility of EYGs is crucial for their development and utilization. The solubilization of EYGs in a weak alkaline environment (pH 7.5-8.5) was investigated through physicochemical properties, microstructure analysis, and metabolomics. The results reveal a significant reduction in the average particle size of EYGs, ranging from 70.49 to 91.28 nm in weakly alkaline conditions. Microstructure and spectroscopic analyses indicate conformational changes in EYGs under these conditions, facilitating the solubilization of proteins, calcium, phosphorus and other components. Furthermore, metabolomics analyses confirms that depolymerization of EYGs promotes the release of glycerophospholipids. These findings underscore the beneficial effects of weakly alkaline conditions on the solubility of EYGs., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Egg yolk granules (EYGs) are water–insoluble components of egg yolk that are rich in protein and phospholipids. Improving the solubility of EYGs is crucial for their development and utilization. The solubilization of EYGs in a weak alkaline environment (pH 7.5–8.5) was investigated through physicochemical properties, microstructure analysis, and metabolomics. The results reveal a significant reduction in the average particle size of EYGs, ranging from 70.49 to 91.28 nm in weakly alkaline conditions. Microstructure and spectroscopic analyses indicate conformational changes in EYGs under these conditions, facilitating the solubilization of proteins, calcium, phosphorus and other components. Furthermore, metabolomics analyses confirms that depolymerization of EYGs promotes the release of glycerophospholipids. These findings underscore the beneficial effects of weakly alkaline conditions on the solubility of EYGs. [Display omitted] • The weakly alkaline condition induced depolymerization of egg yolk granules. • The solubility of egg yolk granules was enhanced in weakly alkaline conditions. • The weakly alkaline condition changed the surface properties of egg yolk granules. • The release of glycerophospholipids was promoted under weakly alkaline conditions. [ABSTRACT FROM AUTHOR]

The various bakery products like cake, cookies, and bread includes egg as an ingredient, which plays significant role in the product development. The egg yolk is the dense yellow part of the egg and is considered nutritionally more beneficial when compared to the other portion of the (egg whites). The egg yolk is considered a rich source of essential fat-soluble vitamins (A, D, E, and K) and few watersoluble vitamins (B6, B12). It is also rich in calcium, magnesium, iron, and selenium. This review discusses about functional characterization like interfacial properties, gelation, and phase separation behavior of egg yolk and its constituents (plasma and granules). This reviews briefly discuss about constituent characterization like xanthophylls, color stability, fatty composition with using newer analysis techniques. Besides, its applications in different industries like bakery, snacks, meat industry and production of nanogels have also been documented. [ABSTRACT FROM AUTHOR]

In batch spawning fish, secondary growth oocytes (SGO) are recruited and spawned in successive cohorts, and multiple cohorts co-occur in spawning-capable females. So far, histological features such as the prevalence of cortical alveoli or yolk granules are conservatively used to distinguish oocytes in different developmental stages which do not necessarily correspond to different cohorts. In this way, valuable information about spawning dynamics remains unseen and consequently misleading conclusions might be drawn, especially for species with high spawning rates and increased overlapping among oocyte cohorts. We introduce a new method for grouping oocytes into different cohorts based on the application of the K-means clustering algorithm on the characteristics of cytoplasmic structures, such as the varying size and intensity of cortical alveoli and yolk granules in oocytes of different development. The method allowed the grouping of oocytes without the need of using oocyte diameter, and thus, a crucial histological bias dealing with the cutting angle and the orientation of reference points (e.g. nucleus) has been overcome. Using sardine, Sardina pilchardus , as a case study, the separation of cohorts provided new insight into the ovarian dynamics, indentifying successive recruitment of up to five oocyte cohorts between SGO recruitment and spawning. These results verified previous histological indications of the number of cohorts in sardine. Altogether, this method represents an improved tool to study species with complex ovarian dynamics. • A new method is presented for grouping oocytes of multiple spawning fish into distinct cohorts. • K-means clustering analysis was applied to the size and intensity of cortical alveoli and yolk globules. • Sardine was used as a case study and was shown to successively recruit up to five secondary oocyte cohorts. • This method can prove important for species with continuous oocyte production and high spawning frequency. [ABSTRACT FROM AUTHOR]

Egg yolk (EY) can be divided into yolk granules (EYG) and yolk plasma (EYP) after water dilution and centrifugation. EYP had a significantly higher lipid content and is predominantly in the form of low-density lipoprotein (LDL) while EYG has a higher protein content. In order to explore the nutritional differences between EY, EYP and EYG, quantitative metabolomic analysis was carried out by ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS). The results showed that a total of 588 small molecule metabolites were identified, mainly glycerol phospholipids (51.59–66.46%), coenzymes, and vitamins (1.21–1.84%). A quantitative comparison showed that amino acids and their metabolites were the most representative metabolites of differential abundance in the contrast of EY and EYG, EYP and EYG. Carbohydrates and their metabolites were the representative metabolites of differential abundance between EY and EYP. The study provided important information for understanding the metabolic composition of EY, EYG, and EYP, as well as providing a reference for utilizing the whole egg. [ABSTRACT FROM AUTHOR]

Many processing parameters influence the physical property and stability of mayonnaise, and producing stable mayonnaise is still more of an art than a science today. The amount of vinegar added before and after emulsification is critical, but its detailed influences and underlying mechanism remained unclear and became the topic of this study. By increasing the amount of vinegar added before the emulsification, the lightness of the prepared mayonnaise decreased, and the greenness and yellowness increased; the viscosity and storage modulus decreased; the droplet sizes increased; the flocculation index decreased; and extractable oil percentage increased. In addition, increasing the amount of vinegar added led to the increase in particle size of egg yolk granules, which ultimately affected the physical property and stability of mayonnaise. Overall, increasing the amount of vinegar added before the emulsification decreases the stability of mayonnaise by affecting the structure of egg yolk granules. These findings lead to a better understanding of the physical processes involved in the production and stabilization of mayonnaise. [Display omitted] • The timing of adding vinegar on mayonnaise's properties and stability was studied. • The associated structural change of egg yolk was monitored. • Adding more vinegar after emulsification produces better mayonnaise. • The observation is associated with the structural change of egg yolk granules. [ABSTRACT FROM AUTHOR]

A method has been devised to study the nutritional role of yolk cholesterol in the development of the chicken (Gallus gallus domesticus) embryo using egg yolk replacement. Preliminary experiments revealed that 11 mL of yolk in medium-sized eggs were adequate to support embryos from 4 to 20 days of incubation, and that low levels of β-cyclodextrin (β-CD) and amyloglucosidase (AG) in yolk were tolerated by the embryo. Fresh egg yolk was treated with β-CD at 50 °C, centrifuged to remove the insoluble β-CD-cholesterol complex, and incubated with AG to degrade residual β-CD. The cholesterol content was reduced from 13.1 mg g-1 in fresh egg yolk to 1.3 mg g-1 in cholesterol-reduced yolk supernatant (CRYS). Yolk granules co-precipitated with the β-CD-cholesterol complex. The cholesterol concentration of CRYS supplemented with granules from fresh yolk (i.e. CRYSg) was 3.2 mg g-1. When yolks of early 5-day embryos were replaced with 11 mL of CRYS, the maximum survival was 17 days of incubation. When yolks were replaced with 11 mL CRYSg, 30% of embryos survived to 20 days, a significant increase in survival compared to CRYS (P < 0.05). Sixty per cent of embryos receiving fresh yolk (yolk controls) and 83% of embryos in intact eggs (intact controls) survived to 20 days. The controls did not differ significantly (P > 0.05). Embryos in the CRYS and CRYSg groups had shorter survivals than yolk controls (P < 0.001) and intact controls (P < 0.005). These results suggest a methodological approach for investigations of egg yolk cholesterol and yolk granules in chick embryo development. [ABSTRACT FROM AUTHOR]

Major yolk protein (MYP) is the most abundant protein found in the yolk granules of sea urchin eggs. The structure of MYPs stored in the eggs of two sea urchin species from Strongylocentrotus intermedius and Mesocentrotus nudus were investigated. Egg-localized major yolk protein (EGMYP) extracted from the eggs of two species of sea urchins was assessed using disc-polyacrylamide gel electrophoresis and immunoelectrophoresis. The molecular weight of native EGMYP was 595 in S. intermedius eggs and 625 kDa in M. nudus eggs. The use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting analysis under reducing conditions revealed that the EGMYP of S. intermedius separated into four bands (approximately 172, 116, 74 and 68 kDa), while the EGMYP of M. nudus resolved as a set of bands ranging from 175 to 58 kDa (approximately 175, 165, 153, 115, 102, 90, 78, 65 and 58 kDa). Yolk granules from eggs were isolated using sucrose density ultracentrifugation and examined using electron microscopy. The structures of purified EGMYP extracted from eggs and from yolk granules were similar in both species. The EGMYP stored in the eggs of the sea urchins was a glycoprotein complex, the protein structure of which, however, varied between the two species. [ABSTRACT FROM AUTHOR]

In this study, a cytochemical method and transmission electron microscopy was used to examine acid phosphatase activities of yolk granules throughout the early developmental stages of the Pacific oyster Crassostrea gigas. This study aimed to investigate the dynamic change of yolk granule acid phosphatase, and the mechanisms underlying its involvement in yolk degradation during the early developmental stages of molluscs. Three types of yolk granules (YGI, YGII, and YGIII) that differed in electron density and acid phosphatase reaction were identified in early cleavage, morula, blastula, gastrula, trochophore, and veliger stages. The morphological heterogeneities of the yolk granules were related to acid phosphatase activity and degrees of yolk degradation, indicating the association of acid phosphatase with yolk degradation in embryos and larvae of molluscs. Fusion of yolk granules was observed during embryogenesis and larval development of C. gigas. The fusion of YGI (free of acid phosphatase reaction) with YGII (rich in acid phosphatase reaction) could be the way by which yolk degradation is triggered. [ABSTRACT FROM AUTHOR]

[Display omitted] • 133 proteins were quantitatively compared over all three periods of egg yolk formation. • The abundance of APOB, VTGs changed significantly during the yolk formation. • Several protein hydrolases and isomerases related to proteins processing varied significantly. • The binding proteins for 3 vitamins and cholesterol were most abundant in the LF period. • The immune system of egg yolk is dynamically adjusted as formation progressed. A quantitative comparison of the proteomes during different periods of the formation of egg yolk, from yellow follicles (YF), small hierarchical follicles (9–12 mm, SF), and the largest hierarchical follicle (LF), was performed. The abundance of major egg yolk proteins (apolipoprotein B and vitellogenins) changed significantly during the yolk formation, and several protein hydrolases and isomerases, which may be related to the processing of egg yolk proteins, also varied significantly. The binding proteins for three vitamins (retinol, riboflavin, and vitamin D) and cholesterol were all most abundant in the LF period, suggesting that these nutrients were transported mainly at the final period of the egg yolk formation. Immunoglobulins decreased and complement proteins increased as formation progressed, indicating the dynamic nature of the egg yolk immune system. These results are helpful for understanding the nutrient composition, the formation of assembly structure, the preservation and processing properties of egg yolk. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fluorescence microscopy with vital dyes verified spontaneous DNA assembly into cell-like structures. [•] Partial phase contrast microscopic images reveal liquid-like materials released from yolk granules. [•] Data presented imply the evidence for spontaneous DNA assembly in the liquid-like materials from yolk granules. [ABSTRACT FROM AUTHOR]

This study examined the process of membrane fusion of yolk granules (YGs) during early embryogenesis of Rhodnius prolixus. We show that eggs collected at days 0 and 3 after oviposition contain different populations of YGs, for example day-3 eggs are enriched in large YGs (LYGs). Day-3 eggs also contain the highest free [Ca2+] during early embryogenesis of this insect. In vitro incubations of day-0 YGs with [Ca2+] similar to those found in day-3 eggs resulted in the formation of LYGs, as observed in vivo. Fractionation of LYGs and small YGs (SYGs) and their subsequent incubation with the fluorescent membrane marker PKH67 showed a calcium-dependent transference of fluorescence from SYGs to LYGs, possibly as the result of membrane fusion. Acid phosphatase and H+-PPase activities were remarkably increased in day-3 LYGs and in calcium-treated day-0 LYGs. Both fractions were found to contain vitellins as major components, and incubation of YGs with calcium induced yolk proteolysis in vitro. Altogether, our results suggest that calcium-induced membrane fusion events take part in yolk degradation, leading to the assembly of the yolk mobilization machinery. [ABSTRACT FROM AUTHOR]

Biogenesis and consumption of the yolk are well-conserved aspects of the reproductive biology in oviparous species. Most egg-laying animals accumulate yolk proteins within the oocytes thus creating the source of nutrients and energy that will feed embryo development. Yolk accumulation drives the generation of a highly specialized oocyte cytoplasm with maternal mRNAs, ribosomes, mitochondria, and, mainly, a set of organelles collectively referred to as yolk granules (Ygs). Following fertilization, the Ygs are involved in regulated mechanisms of yolk degradation to fuel the anabolic metabolism of the growing embryo. Thus, yolk accumulation and degradation are essential processes that allow successful development in many species. Nevertheless, the molecular machinery and mechanisms dedicated to the programmed yolk mobilization throughout development are still enigmatic and remain mostly unexplored. Moreover, while the Ygs functional biology as a nutritional source for the embryo has been acknowledged, several reports have suggested that Ygs cargoes and functions go far beyond yolk storage. Evidence of the role of Ygs in gene expression, microbiota harboring, and paracrine signaling has been proposed. In this study, we summarize the current knowledge of the Ygs functional biology pointing to open questions and where further investigation is needed., (© 2022 Wiley Periodicals LLC.)

[Display omitted] • HIU treatment-induced the depolymerization of chicken egg yolk granules. • HIU treatment increases the dissolution of yolk granule components. • HIU treatment enhanced the hydrogen bond force of yolk granules. • HIU treatment changed the surface properties of yolk particles in water solution. • Emulsifying activity index of yolk granules were improved by HIU treatment. The effects of high-intensity ultrasound (HIU) treatment-induced depolymerization of chicken egg yolk granules were investigated. The results showed that the yolk granules were depolymerized after HIU treatment, and the average particle size was significantly reduced from 289.4 nm (untreated) to 181.4 nm (270-W HIU treatment). All contents of dry matter, protein, calcium and phosphorus in the supernatant of the HIU-treated yolk granule solution increased, which suggests that HIU treatment increases the dissolution of yolk granule components. Spectroscopic analysis showed that HIU treatment increased the polarity of the microenvironment and enhanced the hydrogen bond force of yolk granules. These changes induced by HIU treatment collectively enhanced the zeta potential, decreased the free sulfhydryl group content, and slightly improved the emulsifying activity index of yolk granules. The present study reveals the depolymerization effect of HIU treatment on egg yolk granules and can inspire new potential applications of egg yolk granules. [ABSTRACT FROM AUTHOR]

Serotonin and some selected substances known to interfere with its formation (diethyldithiocarbamate) and function (Catron, 5-methyltryptamine, promethazine) were tested for their ability to affect chick embryo morphogenesis during the first 48 h of development. To detect possible differences in sensitivity between the successive morphogenetic events taking place during this period, the treatment was begun at successively more advanced stages corresponding to embryo ages of between 4 and 30 h incubation. In all cases, the treatment was terminated at an embryo age of 48 h incubation. The treatment was performed both in ovo and in vitro. With some exceptions, the substances induced malformations of the same characteristic types. The developmental processes subjected to disturbances included blastoderm expansion, primitive streak formation, neurulation with brain formation, and somitogenesis. At the cellular level, the malformations can be traced to delayed yolk degradation, impaired formation and function of microvilli, and impaired ability of the embryo cells to change shape. All of the tested chemicals can be expected to interfere with intracellular levels of serotonin. They obviously interfered with decomposition of the yolk granules, recognized centres for intracellular serotonin formation and we therefore conclude that the observed morphogenetical disturbances are ultimately due to impairment of the endogenous serotonin formation. We suggest that, in morphogenesis, serotonin primarily promotes the activity of microtubules and microfilaments. [ABSTRACT FROM AUTHOR]

Chick blastoderms, supplied in vitro and in ovo with L-tryptophan at the primitive streak stage, showed in their continued development typical retardation of brain formation and somitogenesis in the embryo, whereas heart formation remained unaffected. In contrast to an overall reduction in size observed at the higher L-tryptophan concentrations, a moderate enlargement of the area opaca, compared with the controls, was found at the lower concentrations. This enlargement was combined with an increased flattening of the ectodermal area opaca cells and a reduction of the number of microvilli covering these cells. As a simultaneous supply of glucose could reduce, to some extent, the morphogenetic disturbances, these might partly be ascribed to a blocking of gluconeogenesis from L-tryptophan, but the overall reduction in size mentioned, together with the observation of a reduced decomposition of intracellular yolk granules in the L-tryptophan-treated blastoderms, indicates that impairment of intracellular yolk granule decomposition was the principal disturbance. The possible role of serotonin-probably formed from the L-tryptophan supplied-is suggested as a regulating factor in this connexion. [ABSTRACT FROM AUTHOR]

Serotonin distribution in early Ophryotrocha embryos was investigated with fluorescence microscopy based on formaldehyde gas treatment of the embryos, and with light- and electron-microscopic autoradiography after the embryos had been treated withH-5-hydroxytryptophan. Sections of early cleavage embryos showed serotonin-specific fluorescence all over the blastomeres, but it was mainly concentrated on yolk granules, and to a lesser degree on lipid drops and vacuoles. In 2-8 cell embryos, marked regional concentration of serotonin fluorescence was noticeable along the completed cleavage furrows. The autoradiographs confirmed the picture of the yolk granules as the principal site of serotonin formation and serotonin accumulation; considerable amounts were also associated with their decomposition products, i.e. lipid drops, vacuoles, and vesicles, whereas major cell organelles, e.g. mitochondria, were almost totally lacking. Of cytoplasmic structures in the blastomeres without apparent yolk granule origin, only microfilaments, particularly those amassed along the cleavage furrow, showed consistent and significant association with formed serotonin. This suggests a connexion between serotonin and microfilaments and might imply that in early embryo cells the fundamental contractile machinery is controlled by serotonin gradually released from the yolk granules. Within the blastomere nuclei, moderate amounts of serotonin were demonstrated with both fluorescence microscopy and autoradiography. The monoamine oxidase (MAO) inhibitor catron (phenylisopropylhydrazine), used to intensify the autoradiographic picture of serotonin in the Ophryotrocha embryos, markedly increased intragranular serotonin accumulation, but also retarded yolk granule disintegration and delayed the cell cleavage process. In embryos barely able to cleave after treatment with catron, ultrastructural analysis demonstrated that membrane formation at cell cleavage depends on influx of material from the nearby disintegrating yolk granules. [ABSTRACT FROM AUTHOR]

After an intraperitoneal injection of diluted yolk in female quails, young chicks or chick embryos (killed with minimal loss of blood), the absorption of a considerable quantity of yolk granules by the ovarian medullary lacunae can be demonstrated. This can be confirmed by the i.p. injection of killed Hela cells. From our investigation it may be concluded that the avian ovary, by the progressive expansion of its medullary lacunae, develops into a contractile sac-like structure with small openings (communicating with the peritoneal cavity) on its dorsal side. The lacunar system seems to function as an expansion room for the enlarging follicles (also the large pediculated follicles) and intervenes in follicle stalk formation. The relatively rapid uptake by means of an ovarian pumping mechanism of particles and fluid from the peritoneal cavity into the lacunae, suggests also that the latter play a role as diffusion chambers in the supply of nutritious substances to and elimination of wastes from the follicles. [ABSTRACT FROM AUTHOR]

Histochemical characterisation of ooplasm and yolk granules in different stages of oocyte maturation in the ovary was made in the freshwater fairy shrimp Streptocephalus dichotomus. In stage I oocyte, the ooplasm is reactive to basic and acidic groups of protein, aromatic groups such as tryptophenyl and tyrosyl and sulphur containing substances. The other organic compounds include acid mucopolysaccharide and acidic lipids. In stage II oocyte, sudanophilic lipoidal substances appear coinciding with yolk formation. Stage III oocytes are characterised by the abundance of yolk granules which are rich in sulphated acid mucopolysaccharide as well as glycogen. Besides these, the presence of acid phosphatase activity in the ooplasm and nurse cell is also noticed and its functional role in relation to vitellogenesis is discussed. [ABSTRACT FROM AUTHOR]

To determine the localization of the pyrimidine-guanine sequence-specific ribonuclease in Rana catesbeiana (bullfrog) oocytes, the RNase was first isolated and used to prepare a specific rabbit antiserum. Only one protein of similar molecular size to the RNase was immunoprecipitated from ovary homogenate by the antiserum, but two bands were observed by Western blotting analysis. These two proteins were shown by further purification of antibody and Western blotting analysis to have similar antigenicity. Immunoprecipitation and Western blotting of tissue homogenates showed that the RNase was found predominantly in the ovary, but not in other tissues. The specific localization of the RNase was determined by immuno-electron microscopy of oocyte sections incubated with the specific antiserum; the yolk granules, but not other organelles, were found to contain the RNase. Most of the RNase was evenly distributed in the lateral amorphous area of the yolk granule but not in the central yolk crystal area which contains stored vitellogenin proteins. Our results indicate that the RNase is compartmentalized in the yolk granules of oocytes, which might prevent damage to cellular RNAs. [ABSTRACT FROM AUTHOR]

Cortical granules from fertilized eggs, oocytes and nurse cells of Ophryotrocha labronica have been analyzed for the presence of calcium using cryo-ultramicrotomy and X-ray microprobe analysis. All cortical granules showed a significant peak for calcium, but yolk granules were without calcium. These results support the hypothesis that the discharge of cortical granules shortly after fertilization is a self-propagating phenomenon involving the diffusion of Ca from bursting granules. [ABSTRACT FROM AUTHOR]

This study presents the oocyte development of Poecilimon ataturki Ünal, 1999 (Orthoptera, Tettigoniidae) with histology, morphology, and histochemistry by using a stereomicroscope, a light microscope, a scanning electron microscope, and a transmission electron microscope. The ovary in this species is a panoistic type which contains many ovarioles which consist of terminal filament, germarium, and vitellarium. Germarium is the region that has undifferentiated cells which generate the oocytes and follicular cells. In the vitellarium region, yolk granules start to cover the whole oocyte. In histochemical studies, to determine the content of the yolk granules, proteins, and carbohydrates in oocytes were treated with a bromophenol blue (BPB) method, a mercury bromophenol blue (mBPB) method, and a periodic acid Schiff (PAS) method, respectively. As a result of these methods, the yolk granules gave positive results in ovariole sections treated with the PAS and the BPB, while the mBPB staining was negative.