Yolk formation in an annelid (Ophryotrocha puerilis, polychaeta)

Pfannenstiel, H. D.; Grünig, Ch.

doi:10.1016/0040-8166(82)90057-x

Cited by 23 publications

(14 citation statements)

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“…The morphological heterogeneity of mitochondria within cells has been frequently observed in various tissues, i.e., gametes, muscle cells, and nerve cells (Pfannenstiel and Grünig 1982;Weakley 1976;Collins and Bootman 2003;Chan 2006). In the cytoplasm of early dictyotene and previtellogenic oocytes of sturgeon and paddlefish, we have found two morphological types of mitochondria that are divergent in size and cristae distribution.…”

Section: Discussionmentioning

confidence: 96%

“…These mitochondria are assumed to play a role in the formation of a protein or lipid yolk, egg envelope, and nuage (Weakley 1976;Pfannenstiel and Grünig 1982;Begovac and Wallace 1988;Selman and Wallace 1989;Thiaw and Mattei 1992;Eckelbarger and Young 1997;Reunov et al 2000). The transformed mitochondria seem to be a common feature of sturgeon oocytes (Raikova 1974).…”

Section: Discussionmentioning

confidence: 97%

“…The components of lipid droplets are commonly accepted to be synthesized in the ER and Golgi complexes, as manifested in the cell by an "enwrappement" of lipid droplets by ER cisternae or additional membranous structures (Martin and Parton 2005). For a long time, numerous ultrastructural studies of developing ovarian follicles from many different groups of animals, including fish, have suggested that the formation of some yolk components in the oocyte pass through these transformed mitochondria (e.g., Pfannenstiel and Grünig 1982;Kunz 2004;Świątek 2006). The mentioned authors have described mitochondria that acquire a multivesicular or multilamellar appearance and contain material that resembles lipid droplets (Pfannenstiel and Grünig 1982).…”

Section: Discussionmentioning

confidence: 99%

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Possible participation of mitochondria in lipid yolk formation in oocytes of paddlefish and sturgeon

Żelazowska

Kilarski

2007

Cell Tissue Res

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The ovary of paddlefish and sturgeons (Acipenseriformes) is composed of discrete units: the ovarian nests and ovarian follicles. The ovarian nests comprise oogonia and numerous early dictyotene oocytes surrounded by somatic prefollicular cells. Each ovarian follicle consists of a spherical oocyte and a layer of follicular cells situated on a thick basal lamina, encompassed by thecal cells. The cytoplasm of previtellogenic oocytes is differentiated into two distinct zones: the homogeneous and granular zones. The homogeneous cytoplasm is organelle-free, whereas the granular cytoplasm contains numerous organelles, including mitochondria and lipid droplets. We have analyzed the cytoplasm of early dictyotene and previtellogenic oocytes ultrastructurally and histologically. In the cytoplasm of early dictyotene oocytes, two morphologically different types of mitochondria can be distinguished: (1) with well-developed cristae and (2) with distorted and fused cristae. In previtellogenic oocytes, the mitochondria of the second type show various stages of cristae distortion; they contain and release material morphologically similar to that of lipid droplets and eventually degenerate. This process of mitochondrial transformation is accompanied by an accumulation of lipid droplets that form a single large accumulation (lipid body) located in the vicinity of the oocyte nucleus (germinal vesicle). The lipid body eventually disperses in the oocyte center. The possible participation of these mitochondria in the formation of oocyte lipid droplets is discussed.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

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Possible participation of mitochondria in lipid yolk formation in oocytes of paddlefish and sturgeon

Żelazowska

Kilarski

2007

Cell Tissue Res

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“…Furthermore, there was no evidence that nurse cell DNA or plasma membrane is incorporated into the oocyte, which would be expected if nurse cells are completely absorbed by oocytes, as has been suggested by Pfannenstiel and Grü nig, 1982b. We found that the detached nurse cells are usually undergoing programmed cell death, evident as fragmentation of nuclear DNA detectable by TUNEL staining (Gavrieli et al, 1992) (Fig. 5c, lower row).…”

Section: Stage E4mentioning

confidence: 70%

“…Oocytes of Ophryotrocha spp. have previously been shown to be endocytically active (Pfannenstiel and Grü nig, 1982b;Yeow, 1993). Endocytic activity ceases with the transition to stage E5, at which point the oocyte has reached its maximum size.…”

Section: Stage E5mentioning

confidence: 96%

Development of polarized female germline cysts in the polychaete, Ophryotrocha labronica

Brubacher

Huebner

2008

Journal of Morphology

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Polarized oogenic cysts are clonal syncytia in which cellular compartments (cystocytes) differentiate as either oocytes or nurse cells-supportive germ cells that transport material to the oocyte through cytoplasmic bridges. Although polarized cysts have evolved independently in several animal phyla, most research on this phenomenon has focused on insects, particularly Drosophila melanogaster. To provide a foundation for comparative studies of cyst polarization, we have examined the coelomic development of polarized cysts in an annelid worm, Ophryotrocha labronica, using a variety of microscopic techniques. This species has elegantly simple cysts, each consisting of two interconnected cells (one oocyte and one nurse cell) free of somatic follicular tissue. These cysts arise from segmental ovaries, but are released to the coelom early in oogenesis, where they carry out most of their development. Although the oocyte remains transcriptionally active through oogenesis, nurse cells in this species are robust biosynthetic factories, with highly polyploid nuclei, enormous nucleoli, numerous mitochondria, and abundant rough endoplasmic reticulum. Ultimately, the nurse cell dumps its cytoplasm into oocyte, detaches, and undergoes programmed cell death. Although in insects, and possibly some polychaetes, the overall polarity of the cyst is linked to the specification of future embryonic axes in the oocyte, in Ophryotrocha this appears not to be the case. Our findings provide a detailed analysis of cyst development, addressing earlier misconceptions in the literature and adding new insights. This foundation shows the potential of Ophryotrocha labronica as a model system for further experimental analysis of nurse cell-oocyte differentiation.

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Comparative studies on the histology of the ovotestis in Hypselodoris tricolor and Godiva banyulensis (Gastropoda, Opisthobranchia), with special reference to yolk formation

Medina¹,

Garcia²,

Moreno³

et al. 1986

Journal of Morphology

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The histology of the ovotestis was studied by light and electron microscopy in two nudibranch gastropod species. While in Hypselodoris tricolor the ovotestis is intimately associated with the digestive gland tissue, the large gonadal mass of Godiva banyulensis is placed freely in the haemocoele. This fact results in great histological differences between both species. As is common among Mollusca, the immature yolk granule in Hypselodoris and Godiva presumably originates from membrane-rich cytoplasmic inclusions, which we have termed dense multivesicular bodies. Such inclusions consist of an outer membrane enclosing membrane remnants and a granular, electron-dense material. These elements are accumulated and mixed in the center of the dense multivesicular body and could be actually transformed into the paracrystalline core of the immature yolk granule, the cortex of which is made up of part of the central accumulation materials that have not spread into the crystal. During vitellogenesis, some mitochondria are subjected to a process of transformation affecting mainly their inner membrane (including mitochondrial cristae) and matrix. However, the conversion of modified mitochondria into yolk precursors, as reported for other gastropod species, could not be determined with absolute certainty on the basis of our observations on static material. The mature yolk granule consists of a central paracrystalline core, similar in structure to that of the immature yolk granule, and a peripheral membranous cortex, which seems to spread centripetally, thus permitting the crystal to grow. The cortical material consumed in synthesizing the central core appears to be restored by addition of degenerative mitochondria to the yolk granule surface.

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Yolk formation in an annelid (Ophryotrocha puerilis, polychaeta)

Cited by 23 publications

References 18 publications

Possible participation of mitochondria in lipid yolk formation in oocytes of paddlefish and sturgeon

Possible participation of mitochondria in lipid yolk formation in oocytes of paddlefish and sturgeon

Development of polarized female germline cysts in the polychaete, Ophryotrocha labronica

Comparative studies on the histology of the ovotestis in Hypselodoris tricolor and Godiva banyulensis (Gastropoda, Opisthobranchia), with special reference to yolk formation

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