Cell cycle model

Suzuki E, Ollis DF (1989), Cell cycle model for antibody production kinetics, Biotechnol. Bioeng. 34 1398-1402. 

Linardos TI, Kalogerakis N, Behie LA (1992), Cell cycle model for growth rate and death rate in continuous suspension hybridoma cultures, Biotechnol Bioeng. 40 359-368. 

In the cell cycle model, we consider that the probability (P) of transition from G2 to M, at the end of G2, decreases as Weel rises, according to Eq. (1). Conversely, we assume that the probability of premature transition from G2 to M (i.e. before the end of G2, the duration of which was set when the automaton entered G2) increases with the activity of Cdkl according to Eq. (2). The probability is first determined with respect to Cdkl if the G2/M transition has not occurred, the cell progresses in G2. Only at the end of G2 is the probability of transition to M determined as a function of Weel. 

Cell Cycle Modelling for Off-line Dynamic Optimisation of Mammalian Cnltures... 

Mackey, M.C. 1985. A deterministic cell cycle model with transition... 

Fig. 6.8 Changes in the dimension of a cell cycle model (Chen el al. 2000) during a whole cell divisirai cycle (from 0 min till 144.92 min). Grey areas indicate time periods where the highest eigenvalue is positive, i.e. periods of autocatalytic changes (Lovrics et al. 2006)...

Lovrics, A., Csikasz-Nagy, A., Zsely, I.G., Zador, J., Turanyi, T., Novak, B. Time scale and dimension analysis of a budding yeast cell cycle model. BMC Bioinform. 7, 494 (2006)... 

Fig. 8.10 The ctmelation of the sensitivity vector of enzyme Cln2 with the sensitivity vectras of all other variables of the cell cycle model. The investigated parameters were the following kasbf, kisbf, esbfnS, BCKO, CLN3MAX, Dn3 and Jn3. It is clear that cos 0 is close to 1 during most of the time period of the simulated cycle and for most variables, indicating that these sensitivity vectors are locally similar (Lovrics et al. 2008)...

Product formation kinetics in mammalian cells has been studied extensively for hybridomas. Most monoclonal antibodies are produced at an enhanced rate during the Gq phase of the cell cycle (8—10). A model for antibody production based on this cell cycle dependence and traditional Monod kinetics for cell growth has been proposed (11). However, it is not clear if this cell cycle dependence carries over to recombinant CHO cells. In fact it has been reported that dihydrofolate reductase, the gene for which is co-amplified with the gene for the recombinant protein in CHO cells, synthesis is associated with the S phase of the cell cycle (12). Hence it is possible that the product formation kinetics in recombinant CHO cells is different from that of hybridomas. 

II. PROTEIN KINASE ACTIVITY AND REGULATION OF CELL CYCLE EVENTS IN THE YEAST AND SELECTED VERTEBRATE MODEL SYSTEMS... 

Based on the functional analysis of Cdkl and Cdk2 complexes, we have proposed a model for the conversion of the mitotic cell cycle into an endoreduplication cycle (Fig. 1A Edgar Lehner 1996). Accordingly, this cell cycle conversion is dependent on elimination of Cdkl activity and periodic activation of cyclin E/Cdk2. Cyclin E is required for endocycles and a pulse of ectopic cyclin E expression is sufficient to trigger endoreduplication. Cdk2... 

Xenopus oocytes and embryos present a model system for understanding the interface between cell cycle controls and developmental decisions. Maturation of... 

Edgar The competing model will be that fancy promoters are not used to control cell cycle genes, but instead there is some kind of growth coupling mechanism. 

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