scholarly journals The pericentriolar material in Chinese hamster ovary cells nucleates microtubule formation

1977 ◽  
Vol 73 (3) ◽  
pp. 601-615 ◽  
Author(s):  
RR Gould ◽  
GG Borisy
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Carbon Coated ◽  
Pericentriolar Material ◽  
And Function

The structure and function of the centrosomes from Chinese hamster ovary (CHO) cells were investigated by electron microscopy of negatively stained wholemount preparations of cell lysates. Cells were trypsinized from culture dishes, lysed with Triton X-100, sedimented onto ionized, carbon-coated grids, and negatively stained with phosphotungstate. The centrosomes from both interphase and dividing cells consisted of pairs of centrioles, a fibrous pericentriolar material, and a group of virus-like particles which were characteristic of the CHO cells and which served as markers for the pericentriolar material. Interphase centrosomes anchored up to two dozen microtubules when cells were lysed under conditions which preserved native microtubules. When Colcemid-blocked mitotic cells, initially devoid of microtubules, were allowed to recover for 10 min, microtubules formed at the pericentriolar material, but not at the centrioles. When lysates of Colcemid-blocked cells were incubated in vitro with micotubule protein purified from porcine brain tissue, up to 250 microtubules assembled at the centrosomes, similar to the number of microtubules that would normally form at the centrosome during cell division. A few microtubules could also be assembled in vitro onto the ends of isolated centrioles from which the pericentriolar material had been removed, forming characteristic axoneme- like bundles. In addition, microtubules; were assembled onto fragments of densely staining, fibrous material which was tentatively identified as periocentriolar material by its association of CHO can initiate and anchor microtubules both in vivo and in vitro.

scholarly journals Properties of the kinetochore in vitro. I. Microtubule nucleation and tubulin binding.

1985 ◽  
Vol 101 (3) ◽  
pp. 755-765 ◽  
Author(s):  
T J Mitchison ◽  
M W Kirschner
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Lag Phase ◽  
Ovary Cells ◽  
Tubulin Binding ◽  
Mixed Polarity ◽  
Tubulin Immunofluorescence

We have isolated chromosomes from Chinese hamster ovary cells arrested in mitosis with vinblastine and examined the interactions of their kinetochores with purified tubulin in vitro. The kinetochores nucleate microtubule (MT) growth with complex kinetics. After an initial lag phase, MTs are continuously nucleated with both plus and minus ends distally localized. This mixed polarity seems inconsistent with the formation of an ordered, homopolar kinetochore fiber in vivo. As isolated from vinblastine-arrested cells, kinetochores contain no bound tubulin. The kinetochores of chromosomes isolated from colcemid-arrested cells or of chromosomes incubated with tubulin in vitro are brightly stained after anti-tubulin immunofluorescence. This bound tubulin is probably not in the form of MTs. It is localized to the corona region by immunoelectron microscopy, where it may play a role in MT nucleation in vitro.

Mutagenic Activity of p-Toluenesulfonhydrazide

1992 ◽  
Vol 8 (6) ◽  
pp. 369-376 ◽  
Author(s):  
David H. Blakey ◽  
Earle R. Nestmann ◽  
Janet M. Bayley ◽  
K. Laurie Maus ◽  
George R. Douglas
Keyword(s):  
Chinese Hamster Ovary ◽  
Mutagenic Activity ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Gene Mutations ◽  
Metabolic Activation ◽  
High Volume ◽  
Ovary Cells

Toluenesulfonhydrazide (TSH) is a high volume production chemical for which there is relatively little toxicological data. In this study, the mutagenic activity of TSH was determined in the Salmonella/mammalian microsome assay and the in vitro chromosomal aberration assay using Chinese hamster ovary cells. TSH induced gene mutations both with and without metabolic activation in the Salmonella/mammalian microsome assay but that it did not induce chromosomal aberrations in Chinese hamster ovary cells. The results of this study indicate that TSH is an in vitro mutagen and should be assessed for in vivo mutagenicity.

Distribution of pericentriolar material in multipolar spindles induced by colcemid treatment in Chinese hamster ovary cells

1988 ◽  
Vol 89 (1) ◽  
pp. 57-65
Author(s):  
C. Sellitto ◽  
R. Kuriyama
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Marked Rise ◽  
Multipolar Spindle ◽  
Ovary Cells ◽  
Spindle Poles ◽  
Multipolar Spindles ◽  
Pericentriolar Material

Mitotic Chinese hamster ovary cells were obtained by treatment with microtubule drugs under various conditions, and the shape of spindles was analysed by phase-contrast microscopy of isolated spindles, and by indirect immunofluorescence staining of whole mitotic cells with anti-tubulin antibody. Bipolarity of spindles was maintained after treatment with 0.05 microM of colcemid for 3.5 h, but increased exposure to higher concentrations (0.32 microM) and for longer durations (5.5 h) led to a marked rise in multipolar spindles. Nocodazole treatment, on the other hand, failed to show a multiplicity of spindle poles even at 3.3 microM. Each pole of a multipolar spindle was associated with pericentriolar material, as shown by staining with an autoimmune serum specific for pericentriolar material. The number of locations with free pericentriolar material capable of polymerizing microtubules in vitro also increased with increasing numbers of spindle poles, suggesting that dispersion of the pericentriolar material resulted in the production of many microtubule-nucleating sites in multipolar spindles. The different efficiencies of recovery from different drugs, which have been known to be quite variable, may be partly due to the different extent of dispersion of the pericentriolar material.

scholarly journals THE ACTION OF α-AMANITIN ON RNA SYNTHESIS IN CHINESE HAMSTER OVARY CELLS

1974 ◽  
Vol 63 (3) ◽  
pp. 831-842 ◽  
Author(s):  
Claude Kedinger ◽  
Rene Simard
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Mouse Liver ◽  
Rna Synthesis ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Drug Leads ◽  
Nucleolar Rna

α-Amanitin acts in vitro as a selective inhibitor of the nucleoplasmic form B RNA polymerases. Treatment of Chinese hamster ovary (CHO) cells with this drug leads principally to a severe fragmentation of the nucleoli. While the ultrastructural lesions induced by α-amanitin in CHO cells and in rat or mouse liver are quite similar, the results diverge concerning the effect on RNA synthesis. It has been shown that in rat or mouse liver α-amanitin blocks both extranucleolar and nucleolar RNA synthesis. Our autoradiographic and biochemical evidence indicates that in CHO cells high molecular weight extranucleolar RNA synthesis (HnRNA) is blocked by the α-amanitin treatment, whereas nucleolar RNA (preribosomal RNA) synthesis remains unaffected even several hours after the inhibition of extranucleolar RNA synthesis. Furthermore, the processing of this RNA as well as its transport to the cytoplasm seem only slightly affected by the treatment. Finally, under these conditions, the synthesis of the low molecular RNA species (4–5S) still occurs, though less actively. The results are interpreted as evidence for a selective impairment of HnRNA synthesis by α-amanitin in CHO cells.

scholarly journals Taenia solium Oncosphere Adhesion to Intestinal Epithelial and Chinese Hamster Ovary Cells In Vitro

2007 ◽  
Vol 75 (11) ◽  
pp. 5158-5166 ◽  
Author(s):  
Manuela Verastegui ◽  
Robert H. Gilman ◽  
Yanina Arana ◽  
Dylan Barber ◽  
Jeanette Velásquez ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Colorectal Adenocarcinoma ◽  
Chinese Hamster Ovary Cells ◽  
Taenia Solium ◽  
Chinese Hamster ◽  
Host Cells ◽  
Ovary Cells

ABSTRACT The specific mechanisms underlying Taenia solium oncosphere adherence and penetration in the host have not been studied previously. We developed an in vitro adhesion model assay to evaluate the mechanisms of T. solium oncosphere adherence to the host cells. The following substrates were used: porcine intestinal mucosal scrapings (PIMS), porcine small intestinal mucosal explants (PSIME), Chinese hamster ovary cells (CHO cells), epithelial cells from ileocecal colorectal adenocarcinoma (HCT-8 cells), and epithelial cells from colorectal adenocarcinoma (Caco-2 cells). CHO cells were used to compare oncosphere adherence to fixed and viable cells, to determine the optimum time of oncosphere incubation, to determine the role of sera and monolayer cell maturation, and to determine the effect of temperature on oncosphere adherence. Light microscopy, scanning microscopy, and transmission microscopy were used to observe morphological characteristics of adhered oncospheres. This study showed in vitro adherence of activated T. solium oncospheres to PIMS, PSIME, monolayer CHO cells, Caco-2 cells, and HCT-8 cells. The reproducibility of T. solium oncosphere adherence was most easily measured with CHO cells. Adherence was enhanced by serum-binding medium with >5% fetal bovine serum, which resulted in a significantly greater number of oncospheres adhering than the number adhering when serum at a concentration less than 2.5% was used (P < 0.05). Oncosphere adherence decreased with incubation of cells at 4°C compared with the adherence at 37°C. Our studies also demonstrated that T. solium oncospheres attach to cells with elongated microvillus processes and that the oncospheres expel external secretory vesicles that have the same oncosphere processes.

scholarly journals Induction of spermidine/spermine N1-acetyltransferase activity in Chinese-hamster ovary cells by N1N11-bis(ethyl)norspermine (corrected) and related compounds

1990 ◽  
Vol 267 (2) ◽  
pp. 331-338 ◽  
Author(s):  
A E Pegg ◽  
R Pakala ◽  
R J Bergeron
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Competitive Inhibitor ◽  
Polyamine Oxidase ◽  
Enzyme Protein ◽  
Ovary Cells ◽  
Acetyltransferase Activity

Treatment of Chinese-hamster ovary (CHO) cells with N1N11-bis(ethyl)norspermine (BENSM) led to a very large increase in the activity of spermidine/spermine N1-acetyltransferase (SAT), which rose by about 600-fold within 48 h. Smaller, but still very large increases, were also produced in decreasing order of potency by 3,7,11,15,19-penta-azaheneicosane, N1N12-bis(ethyl)spermine and by N1N14-bis(ethyl)homospermine. The rise in acetyltransferase activity was due to an increase in enzyme protein, as indicated by immunoblotting using antibodies directed against rat liver SAT. There was an increase in the content of mRNA for SAT, indicating that BENSM regulates the level of enzyme protein partly by means of a change in transcription or stability of the mRNA. There was also a decreased rate of degradation of the protein in CHO cells trated with the drug. This may be due to the binding of BENSM, which is a competitive inhibitor of the enzyme with a Ki of 120 microM. Exposure to BENSM led to an increased conversion of spermidine into N1-acetylspermidine and putrescine, a rapid fall in the content of intracellular polyamines and the excretion from the cell of putrescine, N1-acetylspermidine and spermidine. When polyamine oxidase activity in the treated cells was blocked, increases in N1-acetylspermidine and N1-acetylspermine were much greater, and the formation of putrescine was prevented. These results indicate that the induction of SAT facilities the degradation of spermine and spermidine to putrescine and the subsequent excretion of putrescine from the cell. When the degradation of the N1-acetyl derivatives by polyamine oxidase is blocked, the cells excrete N1-acetylspermidine instead of putrescine. CHO cells also contained and excreted N8-acetylspermidine, but its synthesis was not increased in cells treated with BENSM, confirming data obtained in vitro that SAT does not produce this derivative.

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