Search results for "Cell Division"
showing 10 items of 457 documents
Cell Cycle in Potentially Dedifferentiating Cereal Mesophyll Protoplasts Cultured in vitro. I. Abnormalities in Cycle Kinetics
1993
Summary Protoplasts isolated from immature and mature mesophyll of wheat and oats were cultured in vitro . The potential progression from G1 (G0) to G2, through mitosis and cytokinesis was analysed. The degree and speed of progression through the cell cycle depended on the species and the state of maturity of the tissue from which the protoplasts were derived. In all the protoplast populations that were tested at least initiation of DNA synthesis was detected by labelling nuclei with the thymidine-analogue, bromodeoxyuridine (BrdU). Protoplasts derived from mature leaf tissue of wheat appeared to be recalcitrant to reach G2. Wheat protoplasts derived from immature leaf tissue appeared to pr…
Isolation and culture of grape vine cv. Chardonnay leaf protoplasts
1990
Experimental conditions were established that resulted in high yields and good viability of the protoplasts obtained from leaves of Vitis vinifera, cv. Chardonnay regenerated in vitro by somatic embryogenesis. The effect of factors of the culture medium and various environmental conditions upon the frequency of cell division has been examined, and a method of culture is described by which protoplasts were induced to begin division. Most protoplasts obtained in this way regenerated cell walls within the first few days and cell division occurred after 10 days of culture in a liquid medium. Some cells have divided two or even three times. Nevertheless, the cells did not continue dividing beyon…
Vascular niche factor PEDF modulates Notch-dependent stemness in the adult subependymal zone.
2009
We sought to address the fundamental question of how stem cell microenvironments can regulate self-renewal. We found that Notch was active in astroglia-like neural stem cells (NSCs), but not in transit-amplifying progenitors of the murine subependymal zone, and that the level of Notch transcriptional activity correlated with self-renewal and multipotency. Moreover, dividing NSCs appeared to balance renewal with commitment via controlled segregation of Notch activity, leading to biased expression of known (Hes1) and previously unknown (Egfr) Notch target genes in daughter cells. Pigment epithelium-derived factor (PEDF) enhanced Notch-dependent transcription in cells with low Notch signaling,…
Synthesis of insulin and its effects in Y79 human retinoblastoma cells
1994
This paper demonstrates that Y79 human retinoblastoma cells contain immunoreactive insulin (IRI) and release it in the medium. Cells cultured either in suspension or in monolayer showed a similar content of IRI. Moreover, in both conditions, IRI concentration was higher in cells cultured in serum-supplemented medium rather than in serum-free medium. Retinoblastoma cells are capable of synthesizing insulin. This was demonstrated by incubating Y79 cells with [3H]leucine. The synthesized radioactive insulin was separated and assayed by means of a HPLC procedure described in this paper. Both cell growth and [3H]thymidine and [3H]uridine incorporation into acid-insoluble fraction was reduced (-7…
Adenine auxotrophy--be aware: some effects of adenine auxotrophy in Saccharomyces cerevisiae strain W303-1A.
2013
Adenine auxotrophy is a commonly used genetic marker in haploid yeast strains. Strain W303-1A, which carries the ade2-1 mutation, is widely used in physiological and genetic research. Yeast extract-based rich medium contains a low level of adenine, so that adenine is often depleted before glucose. This could affect the cell physiology of adenine auxotrophs grown in rich medium. The aim of our study was to assess the effects of adenine auxotrophy on cell morphology and stress physiology. Our results show that adenine depletion halts cell division, but that culture optical density continues to increase due to cell swelling. Accumulation of trehalose and a coincident 10-fold increase in desicc…
Growth control in mammalian cells by cell-cell contacts.
1990
Growth of normal diploid mammalian cells in vitro is strongly regulated by the actual cell density. Cell-cell contacts via specific plasma membrane glycoproteins whose glycan moieties interact with specific receptors has been found to be a main growth regulatory principle. Malignant growth is suggested to result from impaired function of these receptors.
Isolation and Culture of Colon Cancer Stem Cells
2008
Cancer stem cells (CSCs) resemble normal stem cells in several ways. Both cell types are self-renewing and when they divide, one of the daughter cells differentiates while the other retains stem cell properties, including the ability to divide in the same way again. CSCs have been demonstrated to exist in several solid tumors, including colon carcinoma; these cells are able to initiate and sustain tumor growth. There are essentially three different methods to isolate CSCs: establishment culture, the MACS (magnetic cell sorting) technology, and the FACS (fluorescence-activated cell sorting) technology.
Growth of human cells on a non-woven silk fibroin net: a potential for use in tissue engineering.
2003
We have examined a novel biomaterial consisting of a non-woven fibroin net produced from silk (Bombyx mori) cocoons for its ability to support the growth of human cells. Various human cells of different tissue and cell types (endothelial, epithelial, fibroblast, glial, keratinocyte, osteoblast) were examined for adherence and growth on the nets by confocal laser microscopy after staining of the cells with calcein-AM and by electron microscopy. All the cells readily adhered and spread over the individual fibers of the nets. Most of the cells were able to grow and survive on the nets for at least 7 weeks and growth not only covered the individual fibers of the net but generally bridged the ga…
Terminally differentiated postmitotic tumor cells in a rat rhabdomyosarcoma cell line.
1988
A permanent rat rhabdomyosarcoma cell line (BA-HAN-1C) has been established, the phenotype of which is characterized by the coexistence of undifferentiated mononuclear cells and differentiated multinuclear myotube-like giant cells. The failure of attempts to separate these two cell types by repeated recloning procedures indicates their close histogenetic relationship and suggests that differentiation in this tumor proceeds in a similar manner to that in normal striated muscle where postmitotic myotubes arise from mononuclear myoblasts by fusion. The morphologically undifferentiated mononuclear tumor cells were shown to be actively proliferating and to incorporate thymidine methyl-3H(3H-TdR)…
Primary Neural Precursors and Intermitotic Nuclear Migration in the Ventricular Zone of Adult Canaries
1998
New neurons continue to be born in the ventricular zone (VZ) of the lateral ventricles in the brain of adult birds. On the basis of serial section reconstruction and electron microscopy, we determined that the VZ of the adult canary brain is composed of three main cell types (A, B, and E). Type A cells were never found in contact with the ventricle and had microtubule-rich processes typical of young migrating neurons. Type B cells were organized as a pseudostratified epithelium, all contacted the ventricle, and most had a characteristic single cilium. Type E cells, also in contact with ventricle, were ultrastructurally similar to the mammalian multiciliated ependymal cells. After six inject…