The eggshell of <i>Drosophila melanogaster</i>. V. Structure and morphogenesis of the micropylar apparatus

Zarani, Flora E.; Margaritis, Lukas H.

doi:10.1139/z86-372

Cited by 33 publications

(27 citation statements)

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“…The projection comprises numerous microtubules and forms a barrier to the deposition of egg envelopes, which results in the formation of a micropylar canal (Hart, 1990). The same has been observed in numerous insect groups (Yamauchi & Yoshitake, 1984; Zarani & Margaritis, 1985, 1991; Wenzel et al , 1990; Kubrakiewicz et al , 2005).…”

Section: Introductionsupporting

confidence: 82%

Formation and structure of egg envelopes in Russian sturgeon Acipenser gueldenstaedtii (Acipenseriformes: Acipenseridae)

Żelazowska

2010

Journal of Fish Biology

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The covering of the eggs in Russian sturgeon Acipenser gueldenstaedtii consists of three envelopes (the vitelline envelope, chorion and extrachorion) and is equipped with multiple micropyles. The most proximal to the oocyte is the vitelline envelope that consists of four layers of filamentous and trabecular material. The structural components of this envelope are synthesized by the oocyte (primary envelope). The chorion encloses the vitelline envelope. The extrachorion covers the external surface of the egg. Examination of the arrangement of layers that comprise the egg envelopes together with the ultrastructure of follicular cells revealed that the chorion and extrachorion are secondary envelopes. They are secreted by follicular cells and are built of homogeneous material. During formation of egg envelopes, the follicular cells gradually diversify into three morphologically different populations: 1) cells covering the animal oocyte region (cuboid), (2) main body cells (cylindrical) and (3) micropylar cells. The apical surfaces of follicular cells from the first two populations form processes that remain connected with the oocyte plasma membrane by means of gap junctions. Micropylar cells are located at the animal region of the oocyte. Their apical parts bear projections that form a barrier to the deposition of materials for egg envelopes, resulting in the formation of the micropylar canal.

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Section: Introductionsupporting

confidence: 82%

Formation and structure of egg envelopes in Russian sturgeon Acipenser gueldenstaedtii (Acipenseriformes: Acipenseridae)

Żelazowska

2010

Journal of Fish Biology

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“…The micropyle is a narrow channel that extends at an oblique angle from the ventral aspect of the operculum and functions as the sperm entry point during fertilization. After their respective migrations, the border cells and leading edge centripetal cells come together at the anterior of the oocyte to construct this channel (Zarani and Margaritis, 1986). Manipulations that prevent border cells from reaching the oocyte have shown that the centripetal cells play the major role in the construction of the cone projecting from the front of the egg, whereas the border cells create a pore within the cone for sperm entry (Montell et al, 1992).…”

Section: Formation Of Specialized Eggshell Structuresmentioning

confidence: 99%

Mass transit: Epithelial morphogenesis in the Drosophila egg chamber

Horne‐Badovinac

Bilder

2005

Developmental Dynamics

272

284

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Epithelial cells use a striking array of morphogenetic behaviors to sculpt organs and body plans during development. Although it is clear that epithelial morphogenesis is largely driven by cytoskeletal rearrangements and changes in cell adhesion, little is known about how these processes are coordinated to construct complex biological structures from simple sheets of cells. The follicle cell epithelium of the Drosophila egg chamber exhibits a diverse range of epithelial movements in a genetically accessible tissue, making it an outstanding system for the study of epithelial morphogenesis. In this review, we move chronologically through the process of oogenesis, highlighting the dynamic movements of the follicle cells. We discuss the cellular architecture and patterning events that set the stage for morphogenesis, detail individual cellular movements, and focus on current knowledge of the cellular processes that drive follicle cell behavior. Developmental Dynamics 232:559 -574, 2005.

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“…At the which facilitates sperm entry (Zarani and Margaritis 1986). snd (stage 14A) the appendages exhibit two distinct sides with Initially at stage 10B, a number of cells secrete the paracrystalplaques and a network, respectively.…”

Section: Specialized Regionsmentioning

confidence: 99%

“…formation is facilitated by the existence of the liquid crystal like or paracrystalline region. The rest of the micropylar apparatus is formed by migrating peripheral cells and by means of microtubular protrusions which make the micropylar canal (Margaritis 1984;Zarani and Margaritis 1986).…”

Section: Specialized Regionsmentioning

confidence: 99%

The eggshell of Drosophila melanogaster. II. New staging characteristics and fine structural analysis of choriogenesis

Margaritis¹

1986

Can. J. Zool.

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The characteristics of the stages of choriogenesis have been identified using light and electron microscopy. Nine stages have been discerned (11A, 11B, 12A, 12B, 12C, 13A, 13B, 14A, 14B), replacing the four stages used so far (11, 12, 13, 14). Characteristics used to determine the stage of the choriogenesis include (a) the size of oocyte as compared with the whole follicle, (b) the length of the chorionic appendages, and (c) the fine structure of the chorionic layers at the main shell and at the specialized regions. Factors a and b were detected by dark-field light microscopy on living follicles, whereas factor c was studied with electron microscopy. At stage 11A the vitelline membrane has just been completed. At stage 11B the follicle cells secrete the wax layer and the respiratory appendages start to form. Stage 12A follicles secrete endochorion at the anterior pole and the appendages elongate, whereas at stage 12B the main shell follicle cells start to secrete endochorion complex. Stage 12C shows initiation of pillar formation at the main shell and 150 μm long appendages. Stage 13A is characterized by 200 μm long appendages and formation of endochorionic cavities at the main shell, through the participation of a "flocculent" material. At stage 13B the endochorionic "roof is formed, which is completed at stage 14A by the simultaneous formation of the "roof network." The last stage, 14B, exhibits 300 μm long appendages and the secretion of exochorion over the entire follicle. The above stages are accompanied by region-specific formation of specialized structures which include the respiratory appendages, the operculum, the posterior pole, the micropyle, and the collar.

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The eggshell of Drosophila melanogaster. V. Structure and morphogenesis of the micropylar apparatus

Cited by 33 publications

References 0 publications

Formation and structure of egg envelopes in Russian sturgeon Acipenser gueldenstaedtii (Acipenseriformes: Acipenseridae)

Formation and structure of egg envelopes in Russian sturgeon Acipenser gueldenstaedtii (Acipenseriformes: Acipenseridae)

Mass transit: Epithelial morphogenesis in the Drosophila egg chamber

The eggshell of Drosophila melanogaster. II. New staging characteristics and fine structural analysis of choriogenesis

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