Search results for "interphase"

Aequorin-expressing yeast emits light under electric control

2011

In this study, we show the use of direct external electrical stimulation of a jellyfish luminescent calcium-activated protein, aequorin, expressed in a transgenic yeast strain. Yeast cultures were electrically stimulated through two electrodes coupled to a standard power generator. Even low (1.5. V) electric pulses triggered a rapid light peak and serial light pulses were obtained after electric pulses were applied periodically, suggesting that the system is re-enacted after a short refraction time. These results open up a new scenario, in the very interphase between synthetic biology and cybernetics, in which complex cellular behavior might be subjected to electrical control.

Direct detection of repetitive, whole chromosome paint and telomere DNA probes by immunogold electron microscopy

1993

Biotinylated repetitive, whole chromosome paint and telomere DNA probes were investigated at the electron microscope level after non-isotopic in situ hybridization and direct immunogold detection. The protocol described allowed the visualization of a biotinylated chromosome 1 specific satellite DNA probe in the light microscope without silver intensification. This sensitive method was exploited to analyse factors contributing to signal strength in immunogold chromosome painting. Furthermore, it allowed us to investigate the distribution of (TTAGGG)n telomere repeats in human metaphase chromosomes and interphase nuclei. Telomeric and internal (TTAGGG)n repeats were detected at high spatial r…

Induction of micronucleated and binucleate cells in Chinese hamster ovary (CHO) cells by cis-diamminedichloroplatinum (II): a morphological and morph…

1990

Abstract The mutagenicity and cytotoxicity of cis -diamminedichloroplatinum (II) (cisplatin) at doses of 5, 10 and 20 μg/ml in Chinese hamster ovary (CHO) cells have been examined. A morphological characterization of several cell types induced by cisplatin was carried out. The frequencies of both cells with micronuclei and binucleate cells as a time-dependent parameter have also been studied. Whilst the number of cells with micronuclei was found to decrease with time, the number of binucleate cells increased. The possible kinetic mechanism for the production of binucleate cells and cells with micronuclei is discussed. A morphometric analysis was also performed. The nuclear area in both trea…

Treatment with the anti-tumor drugs, cis-platin and mafosfamide, does not affect the structure of prekinetochores in a human breast cancer cell line.…

1996

Abstract The goal of the present article was to determine whether a nuclear parameter, centromere structure of interphase cells, could serve as an indicator to assess cellular damage caused by anti-tumor drugs. These were cis-platin and mafosfamide, which are widely used for the management of solid tumors. To visualize the centromeres, we probed treated and untreated cells of a human breast cancer cell line, MX-1, with a human anti-centromere serum. The serum was obtained from a scleroderma patient and detects antigens associated with prekinetochores of the decondensed chromosomes. The DNA was simultaneously displayed by a specific fluorescent dye. The cells were grown on coverslips, incuba…

ORGANIZATION OF HIGHER-LEVEL CHROMATIN STRUCTURES (CHROMOMERE, CHROMONEMA AND CHROMATIN BLOCK) EXAMINED USING VISIBLE LIGHT-INDUCED CHROMATIN PHOTO-S…

2002

The method of chromatin photo-stabilization by the action of visible light in the presence of ethidium bromide was used for investigation of higher-level chromatin structures in isolated nuclei. As a model we used rat hepatocyte nuclei isolated in buffers which stabilized or destabilized nuclear matrix. Several higher-level chromatin structures were visualized: 100 nm globules—chromomeres, chains of chromomeres—chromonemata, aggregates of chromomeres—blocks of condensed chromatin. All these structures were completely destroyed by 2 M NaCl extraction independent of the matrix state, and DNA was extruded from the residual nuclei (nuclear matrices) into a halo. These results show that nuclear …

Micronucleus frequencies and clonogenic cell survival in TK6 cells exposed to changing dose rates under controlled temperature conditions.

2014

In most exposure scenarios the dose rate of exposure is not constant. Despite this, very little information exists on the possible biological effects of exposing cells to radiation under the conditions of a changing dose rate. The current study highlights interesting effects following exposure under these conditions.We constructed a new exposure facility that allows exposing cells inside an incubator and used it to irradiate human lymphoblastoid TK6 cells both after a moderate (0.48 Gy) and a high (1.1 Gy) dose, where the change in dose rate was, respectively, ≈ 17-fold (2.2-37 mGy/min) and ≈ 39-fold (2.7-106 mGy/min). Clonogenic survival and micronuclei (MN) induction were the chosen endpo…

Interphase Model and Phase-Field Approach for Strain Localization

2020

Quasi-brittle materials subjected to a high level of mechanical solicitations see the development in relatively narrow zone of micro-cracks that coalesce into stress free cracks. In this work, the problem of strain localization in elastoplastic materials exhibiting softening has been approached by applying the interphase model together with the phase-field theory. In particular, the narrow zone where strains concentrate, usually named process zone or localization band, is kinematically modeled using the interphase model, while the phase-field variable is introduced to regularize the contact strains at the interface between the plastic strain band and the surrounding material. This correspon…

Domain wall splitting and creation of the fine domain structure

1998

Abstract The study of the movement of the paraelectric-ferroelectric interphase boundary in (Ba,Sr)TiO 3 with concentration change is provided in the framework of the mean-field theory. The analytical solution for the parameters of motion of the interphase boundary is applied to the calculations of the splitting of domain walls in (Ba,Sr)TiO 3 for different concentrations of Sr. The calculations are based on the experimental data for the Curie–Weiss constant and for the parameters of the Landau–Ginzburg expression for the free energy.

The interphase model applied to simulate chemically bonded anchors

2009

Detection of cytokeratin dynamics by time-lapse fluorescence microscopy in living cells.

1999

To monitor the desmosome-anchored cytokeratin network in living cells fusion protein HK13-EGFP consisting of human cytokeratin 13 and the enhanced green fluorescent protein was stably expressed in vulvar carcinoma-derived A-431 cells. It is shown for A-431 subclone AK13-1 that HK13-EGFP emits strong fluorescence in fixed and living cells, being part of an extended cytoplasmic intermediate filament network that is indistinguishable from that of parent A-431 cells. Biochemical, immunological and ultrastructural analyses demonstrate that HK13-EGFP behaves identically to the endogenous cytokeratin 13 and is therefore a reliable in vivo tag for this polypeptide and the structures formed by it. T…