Search results for "MICROTUBULES"
showing 10 items of 71 documents
Abnormal mitotic spindle assembly and cytokinesis induced by D-Limonene in cultured mammalian cells
2013
D-Limonene is found widely in citrus and many other plant species; it is a major constituent of many essential oils and is used as a solvent for commercial purposes. With the discovery of its chemotherapeutic properties against cancer, it is important to investigate the biological effects of the exposure to D-Limonene and elucidate its, as yet unknown, mechanism of action. We reported here that D-Limonene is toxic in V79 Chinese hamster cells in a dose-dependent manner. Moreover, to determine the cellular target of D-Limonene, we performed morphological observations and immunocytochemical analysis and we showed that this drug has a direct effect on dividing cells preventing assembly of mito…
Microtubule distribution in gravitropic protonemata of the mossCeratodon
1990
Tip cells of dark-grown protonemata of the moss Ceratodon purpureus are negatively gravitropic (grow upward). They possess a unique longitudinal zonation: (1) a tip group of amylochloroplasts in the apical dome, (2) a plastid-free zone, (3) a zone of significant plastid sedimentation, and (4) a zone of mostly non-sedimenting plastids. Immunofluorescence of vertical cells showed microtubules distributed throughout the cytoplasm in a mostly axial orientation extending through all zones. Optical sectioning revealed a close spatial association between microtubules and plastids. A majority (two thirds) of protonemata gravistimulated for > 20 min had a higher density of microtubules near the lowe…
Development of the filiform hairs on the cerci of Gryllus bimaculatus Deg. (Saltatoria, Gryllidae)
1978
The filiform hairs, mechanoreceptors of Gryllus, pass through six developmental stages during the last larval stage. The cytoplasm of their sense cells suggests intensive synthesis of protein for cellular metabolism and intercytoplasmic exchange of material via glial evaginations. Ultrahistochemical tests demonstrated acid phosphatase in the lysosomes as well as in components of the Golgi apparatus. There was no significant change in the appearance of the sense cell cytoplasm, indicating a maintained functional state also during molting. The new cuticular apparatus is formed after apolysis by the three enveloping cells. Formation of the replacement hairs is initiated by a cytoplasmic outgro…
Dissection of keratin dynamics: different contributions of the actin and microtubule systems.
2005
It has only recently been recognized that intermediate filaments (IFs) and their assembly intermediates are highly motile cytoskeletal components with cell-type- and isotype-specific characteristics. To elucidate the cell-type-independent contribution of actin filaments and microtubules to these motile properties, fluorescent epithelial IF keratin polypeptides were introduced into non-epithelial, adrenal cortex-derived SW13 cells. Time-lapse fluorescence microscopy of stably transfected SW13 cell lines synthesizing fluorescent human keratin 8 and 18 chimeras HK8-CFP and HK18-YFP revealed extended filament networks that are entirely composed of transgene products and exhibit the same dynamic…
Identification of a Dynein Interacting Domain in the Papillomavirus Minor Capsid Protein L2
2006
ABSTRACT Papillomaviruses enter cells via endocytosis (H. C. Selinka et al., Virology 299:279-287, 2002). After egress from endosomes, the minor capsid protein L2 accompanies the viral DNA to the nucleus and subsequently to the subnuclear promyelocytic leukemia protein bodies (P. M. Day et al., Proc. Natl. Acad. Sci. USA 101:14252-14257, 2004), suggesting that this protein may be involved in the intracytoplasmic transport of the viral genome. We now demonstrate that the L2 protein is able to interact with the microtubule network via the motor protein dynein. L2 protein was found attached to microtubules after uncoating of incoming human papillomavirus pseudovirions. Based on immunofluoresce…
Synthesis and evaluation of microtubule assembly inhibition and cytotoxicity of prenylated derivatives of cyclo-l-Trp-l-Pro
2000
The synthesis of three isoprenylated derivatives of cyclo-L-Trp-L-Pro is described. These substances have been evaluated for cytotoxic activity in rat normal fibroblast 3Y1 cells and have also been evaluated in vitro for the inhibition of microtubule assembly.
The Dorsocross T-box transcription factors promote tissue morphogenesis in the Drosophila wing imaginal disc.
2012
The Drosophila wing imaginal disc is subdivided into notum, hinge and blade territories during the third larval instar by formation of several deep apical folds. The molecular mechanisms of these subdivisions and the subsequent initiation of morphogenic processes during metamorphosis are poorly understood. Here, we demonstrate that the Dorsocross (Doc) T-box genes promote the progression of epithelial folds that not only separate the hinge and blade regions of the wing disc but also contribute to metamorphic development by changing cell shapes and bending the wing disc. We found that Doc expression was restricted by two inhibitors, Vestigial and Homothorax, leading to two narrow Doc stripes…
Microtubules and intermediate filaments of herpes simplex virus infected cells.
1987
The fate of microtubules and of vimentin or keratin containing intermediate filaments during infection with fusion or rounding producing strains of herpes simplex virus (HSV) was investigated. Microtubules polymerize early after fusion of cells. However, they do not reconstitute 6–7 hours post infection (p.i.) after release of a colcemid block. Keratin and vimentin are maintained around the original nucleus still inside of recruited cells in the polykaryocyte. Cells of fibroblastic and epithelial origin fuse. Inside of polykaryocytes keratin or vimentin containing fibers seem to polymerize. Keratin is to be found in invaginations in the nuclei surrounded by the inner layer of the nuclear me…
Nimbolide inhibits 2D and 3D prostate cancer cells migration, affects microtubules and angiogenesis and suppresses B-RAF/p.ERK-mediated in vivo tumor…
2021
Abstract Background Prostate cancer (PCa) is the most prominent malignancy among men worldwide. PCa cells have a high tendency to metastasize to various distant organs, and this activity is the main cause of PCa mortality. Nimbolide is a promising phytochemical constituent of neem Azadirachta indica (Meliaceae). Previous studies showed that nimbolide exhibited potent anticancer activity however, its role against PCa tumorigenesis has not been fully elucidated. Purpose Our work aims to explore the role of nimbolide in regulating the essential tumor-associated processes involved in the metastatic cascade in PCa cells. Study design Cytotoxicity assay, wound healing and spheroid invasion assays…
Centrifugation does not alter spatial distribution of `BEP4' mRNA in paracentrotus lividus EGG
1997
AbstractParacentrotus lividus unfertilized eggs were centrifuged in a sucrose gradient, so to split each into two parts: a nucleated light fragment and an anucleated heavy fragment. Northern blot analyses utilizing a bep4 probe as animal marker and H2A histone gene and 12S-mit RNA as controls indicate that the eggs are elongated along the animal-vegetal axis during centrifugation and thereafter split into an animal and a vegetal half. Treatment of the eggs with colchicine before centrifugation abolishes the animal localization of bep4 mRNA.