The ovary of the gonochoristic marine triclad Sabussowia dioica: ultrastructural and cytochemical investigations

Tekaya, Saïda; Falleni, Alessandra; Dhainaut, A.; Zghal, Fathia; Gremigni, Vittorio

doi:10.1016/s0968-4328(98)00035-3

Cited by 13 publications

(18 citation statements)

References 29 publications

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“…By contrast, the oocytes of the other two families of freshwater triclads (Planariidae and Dendrocoelidae) are devoid of yolk globules and are provided with small granules forming a monolayer in the cortical ooplasm (Gremigni, 1969b(Gremigni, , 1979. In the marine species studied to date, the oocytes of Cercyra hastata and Sabussowia dioica (Cercyridae) both show aggregates of ribonucleoproteins, which have been interpreted as a special kind of yolk, and small cortical granules (Gremigni and Nigro, 1983;Tekaya et al, 1999), while those of Procerodes dohrni (Procerodidae) are provided with cortical granules and lack yolk (Gremigni et al, 1986;Gremigni, 1988). The vitellocytes of freshwater triclads are filled with both reserve material (yolk globules, lipids, and glycogen) and cocoon-shell globules with a concentric or convoluted-like pattern of the content that reacts positively to the cytochemical test for polyphenols .…”

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Ultrastructural and cytochemical aspects of the female gonad of Geoplana burmeisteri (Platyhelminthes, Tricladida, Terricola)

Falleni

Lucchesi

Ghezzani

et al. 2005

Journal of Morphology

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The ultrastructure of the female gonad of the land planarian Geoplana burmeisteri was investigated by means of electron microscopy and cytochemical techniques. It consists of two small germaria located ventral to the intestine and of two irregular, lateral rows of vitelline follicles, both enveloped by a tunica composed of an extracellular lamina and an inner sheath of accessory cells. Accessory cell projections completely surround developing oocytes and vitellocytes. The main feature of oocyte maturation is the appearance of chromatoid bodies and the development of the rough endoplasmic reticulum (RER) and Golgi complexes. These organelles appear to be correlated with the production of egg inclusions of medium electron density, about 1.5-1.8 microm in diameter, which remain scattered in the ooplasm of mature oocytes. On the basis of cytochemical tests demonstrating their glycoprotein composition, these inclusions were interpreted as residual yolk globules. Vitellocytes are typical secretory cells with well-developed RER and Golgi complexes that are mainly involved in the production of yolk globules and eggshell globules, respectively. Eggshell globules appear to arise from repeated coalescence of small Golgi-derived vesicles and, at an intermediate stage of maturation, show a multigranular pattern. Later, after vesicle fusion, they reach a diameter of 1.3-1.6 microm when completely mature and show a meandering/concentric pattern, as is typical of the situation seen in most Proseriata and Tricladida. The content of yolk globules is completely digested by pronase, while the content of eggshell globules is unaffected. Mature vitellocytes contain, in addition, a large quantity of glycogen and lipid droplets as further reserve material. On the basis of the ultrastructural characteristics of the female gonad described above and in relation to the current literature, we conclude that G. burmeisteri appears to be more closely related to the freshwater triclads, in particular to members of the Dugesiidae, than to the marine triclads.

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confidence: 99%

Ultrastructural and cytochemical aspects of the female gonad of Geoplana burmeisteri (Platyhelminthes, Tricladida, Terricola)

Falleni

Lucchesi

Ghezzani

et al. 2005

Journal of Morphology

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“…Cortical granules are usually interpreted as endogenous Golgi complex productions [1,3,4,7,8]. In some metazoan (as crustacean), it is suggested that mitochondria take part in the origin of cortical granules [3].…”

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“…The ovary of the gonochoristic planarian S. dioica is studied by light and transmission electron microscope as detailed in [1].…”

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confidence: 99%

“…Cortical granules are membrane-bound, electron dense cell inclusions known in oocytes of many animals, invertebrates [1][2][3][4][5] and vertebrates [6]. They are distributed in the peripheral ooplasm forming a monolayer beneath the plasma membrane [1,3,5].…”

Section: Introductionmentioning

confidence: 99%

“…They are distributed in the peripheral ooplasm forming a monolayer beneath the plasma membrane [1,3,5]. These organelles are interpreted as Golgi complex productions [1,3,4,7,8].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Endocytotic Activity during the Cortical Granules Genesis in Marine Planarian Oocytes (Platyhelminthe, Tricladida)

Tekaya¹

2015

Single Cell Biol

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Ultrastructure of the ovary and oogenesis in the flatworm Prosthiostomum siphunculus (Polycladida, Cotylea)

Gammoudi

Salvenmoser

Tekaya

et al. 2016

Cell Biology International

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Based on light and electron microscopy observations, oogenesis in the cotylean polyclad Prosthiostomum siphunculus was investigated for the first time. The numerous ovarian follicles are dispersed essentially in the dorsal parenchyma. In the follicles, a ventral germinative zone with undifferentiated germs cells of different sizes and a dorsal growth zone with larger growing and abortive oocytes are present. The oogenesis could be subdivided into four stages: (1) Oogonia with a dark nucleus and a dark, ribosome-rich cytoplasm. (2) Early oocyte stage, represented by relatively small cells (10 μm in diameter), a cytoplasm showing some mitochondria and some endoplasmic reticula. (3) Previtellogenic stage, with a decrease of the nucleo-cytoplasmic ratio due to the remarkable increase in ooplasm volume. Immature eggshell globules are observed. (4) Vitellogenic stage, including early vitellogenic ovarian stage, in which a second type of globule (inclusion globule) is formed, and a late vitellogenic uterine stage, in which the inclusion globules are not present anymore. The mature eggshell globules form a peripheral layer under the cell membrane. Eggshell and inclusion globules were analyzed with electron energy loss spectroscopy, electron spectroscopic imaging, protease treatment, and with periodic acid thiocarbohydracide silver proteinate to detect polysaccharides. Chromatoid bodies are present in all four stages. For the first time in a flatworm, we provide evidence that accessory cells, forming a tunica around the ovarian follicles, are epithelial or epithelium-like and likely contribute nutrients for the growth of the oocytes.

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The ovary of the gonochoristic marine triclad Sabussowia dioica: ultrastructural and cytochemical investigations

Cited by 13 publications

References 29 publications

Ultrastructural and cytochemical aspects of the female gonad of Geoplana burmeisteri (Platyhelminthes, Tricladida, Terricola)

Ultrastructural and cytochemical aspects of the female gonad of Geoplana burmeisteri (Platyhelminthes, Tricladida, Terricola)

Endocytotic Activity during the Cortical Granules Genesis in Marine Planarian Oocytes (Platyhelminthe, Tricladida)

Ultrastructure of the ovary and oogenesis in the flatworm Prosthiostomum siphunculus (Polycladida, Cotylea)

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