Cytoplasmic bridges within the follicular epithelium of the ovarioles of two diptera, <i>Aedes Aegypti</i> and <i>Stomoxys Calcitrans</i>

Meola, Shirlee M.; Mollenhauer, Hilton H.; Thompson, James

doi:10.1002/jmor.1051530105

Cited by 18 publications

(3 citation statements)

References 16 publications

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“…Intercellular bridges were revealed by anti-mucin Ab staining of Drosophila tissues not only in germ line, but also in somatic cells. Small intercellular bridges have been described earlier by EM studies in follicle cells and in imaginal discs of different insect species (Van Ruiten and Sprey, 1974;Meola et al, 1977;Ramamurty and Engels, 1977;Fiil, 1978), including Drosophila (Poodry and Schneiderman, 1970;Giorgi, 1978), and, as transient structures, found in Drosophila embryonic cells. The latter include short-lived bridges that are detectable at late stages of cellularization at sites where embryonic cells contact with the yolk sac (Rickoll, 1976), and in certain cells following mitoses in the post-gastrulation embryo (Rickoll and Counce, 1980).…”

Section: Mucin-d Is Present In Intercellular Bridges In Various Somatmentioning

confidence: 60%

Mucinoprotein is a universal constituent of stable intercellular bridges inDrosophila melanogaster germ line and somatic cells

Kramerova

Kramerov

1999

Dev. Dyn.

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Intercellular bridges formed by incomplete cytokinesis may be important in a variety of processes, including synchronization of mitotic and meiotic divisions in animal cells. Using specific antibodies against a mucin‐type glycoprotein (Kramerov et al. 1996 FEBS Lett. 378:213–218) from Drosophila melanogaster cultured embryonic cells, we showed that this glycoprotein is located in all cytoplasmic bridges found in various germline and somatic tissues. In the ovary, immunostaining of ring canals connecting germ cells can be detected in the very early stages at the germarium region 1 where first gonial divisions take place, and the immunostaining appears to persist through late stages when transport of cytoplasm from nurse cells to a growing oocyte occurs. Each ring canal is made up of an outer and an inner rim. Mucin glycoprotein appears to be one of the first proteins localized to the outer rim, which is a derivative of the arrested cleavage furrow. The known ring canal proteins, phosphotyrosine‐containing protein(s), F‐actin, hts‐ and kelch proteins, are localized to the inner rim at a later developmental time. Similarly, mucin glycoprotein is recruited early to ring canals connecting mitotic primary spermatocytes in both larval and adult testes. Mucin glycoprotein was found to be present in intercellular bridges (small ring canals) in somatic cells, including follicular epithelium in ovary and imaginal disc cells. Intercellular bridges were observed for the first time in a subset of cells in the larval brain. Thus, mucin glycoprotein is the only protein hitherto found in all known types of stable intercellular bridges and may be an important constituent of a backbone needed for assembly and preservation of this particular type of cell‐cell contact. Dev Dyn 1999;216:349–360. ©1999 Wiley‐Liss, Inc.

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Section: Mucin-d Is Present In Intercellular Bridges In Various Somatmentioning

confidence: 60%

Mucinoprotein is a universal constituent of stable intercellular bridges inDrosophila melanogaster germ line and somatic cells

Kramerova

Kramerov

1999

Dev. Dyn.

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“…Somatic ring canals were detected decades ago by electron microscopy of insect follicle cells that encapsulate germline cells in egg chambers (Fiil, 1978;Giorgi, 1978;Meola et al, 1977;Ramamurty and Engels, 1977), and of imaginal discs present in larvae (Poodry, 1970). They appear to result from the stabilization of mitotic intercellular bridges, as in the germline.…”

Section: Introductionmentioning

confidence: 99%

Intercellular protein movement in syncytial Drosophila follicle cells

Airoldi¹,

McLean²,

Shimada³

et al. 2012

Development

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SummaryRing canals connecting Drosophila germline, follicle and imaginal disc cells provide direct contact of cytoplasm between cells. To date, little is known about the formation, structure, or function of the somatic ring canals present in follicle and imaginal disc cells. Here, we show by confocal and electron microscopy that Pavarotti kinesin-like protein and Visgun are stable components of somatic ring canals. Using live-cell confocal microscopy, we show that somatic ring canals form from the stabilization of mitotic cleavage furrows. In contrast to germline cells, syncytial follicle cells do not divide synchronously, are not maximally branched and their ring canals do not increase in size during egg chamber development. We show for the first time that somatic ring canals permit exchange of cytoplasmic proteins between follicle cells. These results provide insight into the composition and function of ring canals in somatic cells, implying a broader functional significance for syncytial organization of cells outside the germline.

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“…This procedure was repeated until DFB caused some measurable effect on the cell cultures, such as changes in morphology, plating efficiency, pigment production or secretion or both, or changes in tumor induction in mice. Cells were harvested from each group as described above, and pellets were prepared for transmission electron microscopy by fixation in glutaraldehyde followed by postfixation in OS04 in phosphate buffer (5). A minimum of 10 pellets were sectioned of the three replicates of each of the three treatments.…”

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confidence: 99%

Inhibition of melanogenesis in B16-F1 melanoma cells after exposure to diflubenzuron

Norman¹,

Meola²

1983

Antimicrob Agents Chemother

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The insect growth regulator diflubenzuron was found to be a potent inhibitor of melanosome synthesis and release in mouse melanoma cell cultures, and after three to five successive passages of melanoma cells in growth medium containing this compound, these cells were unable to produce monolayers in untreated medium and were incapable of inducing tumor formation in mice. This is the first time that an insect growth regulator has been shown to have a deleterious effect on malignant cells of animals.Because the insect growth regulator diflubenzuron (Dimilin; TH 6040; 1-(4-chlorophenyl)-3-(2,6-diflubenzoyl)-urea) has been found to disrupt insect epidermal cell histogenesis (4), we suspected that this compound also has a deleterious effect on melanoma cells, which, like the epidermal cells of insects, are of ectodermal origin (6). Thus, two murine melanoma cell cultures were exposed through several cell passages to diflubenzuron (DFB). These two cultures were the melanotic B16-F1 and the amelanotic B16-A melanoma cells.The melanoma cell cultures (low, <8 passages) were grown in Dulbecco modified Eagle medium (high glucose) supplemented with 10% fetal calf serum, 100 U of penicillin per ml, and 100 ,ug of streptomycin (GIBCO Laboratories, Grand Island, N.Y.) per ml. Cultures were harvested with the aid of a trypsin-EDTA solution (0.05 and 0.02%, respectively), suspended in Dulbecco medium, and seeded at concentrations of 105 cells per 100-mm polystyrene culture dish (Corning Glass Works, Corning, N.Y.), and incubated at 37°C in an atmosphere of 5% CO2 and 95% air. After 24 h of incubation, the medium was decanted, and the cells were divided into three groups. One group received Dulbecco growth medium, the second group received medium containing 0.1% dimethyl sulfoxide (Aldrich Chemical Co., Milwaukee, Wis.), and the third group received medium containing 12.5 ,ug of DFB (Thompson-Hayward Chemical Co., Kansas City, Kans.) per ml dissolved in dimethyl sulfoxide. After an additional 48 h of incubation, the medium was removed, and the cells were harvested as described above.Cells from each treatment were enumerated with the aid of a hemacytometer, and viability was determined by trypan blue exclusion and plating efficiency tests. Protein concentrations were determined by the Bio-Rad system (1), and melanin content was determined by spectrophotometric analysis (3). Spectrophotometric measurements were also made on incubation medium to determine the amount of melanin secreted. The control medium for determination of melanin content of the growth medium was the medium in which the B16-A amelanotic cells had been grown. Cells were harvested from three plates of each treatment for each determination. Six C57BL mice were inoculated subcutaneously with 0.2-ml cell suspensions (104 viable cells) from each group. Cells from each group were then replated in the same medium from which they were harvested, at concentrations of 105 cells per plate. This procedure was repeated until DFB caused some measurable effect on the cell culture...

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Cytoplasmic bridges within the follicular epithelium of the ovarioles of two diptera, Aedes Aegypti and Stomoxys Calcitrans

Cited by 18 publications

References 16 publications

Mucinoprotein is a universal constituent of stable intercellular bridges inDrosophila melanogaster germ line and somatic cells

Mucinoprotein is a universal constituent of stable intercellular bridges inDrosophila melanogaster germ line and somatic cells

Intercellular protein movement in syncytial Drosophila follicle cells

Inhibition of melanogenesis in B16-F1 melanoma cells after exposure to diflubenzuron

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