Search results for "Growth phase"
showing 4 items of 4 documents
Neuronal cell cycle: the neuron itself and its circumstances.
2015
Neurons are usually regarded as postmitotic cells that undergo apoptosis in response to cell cycle reactivation. Nevertheless, recent evidence indicates the existence of a defined developmental program that induces DNA replication in specific populations of neurons, which remain in a tetraploid state for the rest of their adult life. Similarly, de novo neuronal tetraploidization has also been described in the adult brain as an early hallmark of neurodegeneration. The aim of this review is to integrate these recent developments in the context of cell cycle regulation and apoptotic cell death in neurons. We conclude that a variety of mechanisms exists in neuronal cells for G1/S and G2/M check…
Oxygen Consumption Rate of Tumour Cells as a Function of their Proliferative Status
1987
The oxygen consumption rate \(\left( \dot{Q}{{O}_{2}} \right)\) of EMT6/Ro-cells cultured as monolayers was investigated as a function of their proliferative status. The transition of these cells from the exponential to the plateau growth phase was associated with a continuous decrease in \(\dot{Q}{{O}_{2}}\) per single cell. This decrease can partially be attributed to a corresponding decline in cellular volume. In addition, the \(\dot{Q}{{O}_{2}}\) per cell volume was also reduced during the passage of the cells through the growth phase described. The results lead to the conclusion that a reduction in cellular volume and factors which are still unknown may contribute to the metabolic chan…
Developmental control of the heat-shock stress regulon in Streptomyces coelicolor
1995
In the differentiating eubacterium Streptomyces coelicolor, nutritional imbalances activate a developmental programme which involves the heat-shock stress regulon. In liquid batch cultures, the growth curve could be separated into four components: rapid growth 1 (RG1), transition (T), rapid growth 2 (RG2) and stationary (S). Patterns of gene expression in cultures subjected to heat shock in various phases were recorded on two-dimensional gels and analysed using advanced statistical methods. The responses of all heat-shock proteins (HSPs) were highly dependent upon the growth phase, thus demonstrating that the four phases of growth were physiologically distinct. For many HSPs, the levels of …
N-Glycosylation modification of proteins is an early marker of the enterocytic differentiation process of HT-29 cells
1990
International audience; The human colon cancer cell line HT-29 remains totally undifferentiated when glucose is present in the culture medium (HT-29 Glc+), while the same cells may undergo typical enterocytic differentiation after reaching confluence when grown in glucose-deprived medium (HT-29 Glc-). Recently, we demonstrated a deficiency in the overall N-glycan processing in confluent undifferentiated cells, whereas differentiated cells follow a classical pattern of N-glycosylation. The main changes in N-glycosylation observed in confluent undifferentiated cells may be summarised as follows: 1) the conversion of high mannose into complex glycopeptides is greatly decreased; 2) this decreas…