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Modeling with Delay Differential Equations
Published in Sandip Banerjee, Mathematical Modeling, 2021
where M(t) and P(t) are the concentrations of Hes1 mRNA and Hes1 protein, μm and μp are the degradation rates of mRNA and Hes1 protein, respectively, αm is the transcript initiation rate in the absence of Hes1 protein, and αp is the production rate of Hes1 protein from Hes1 mRNA, the discrete time delay τ results from the processes of translation and transcription, P0 is the repression threshold, and n is a Hill coefficient.
Experimental Results on Cellular and Subcellular Systems Exposed to Low-Frequency and Static Magnetic Fields
Published in Ben Greenebaum, Frank Barnes, Biological and Medical Aspects of Electromagnetic Fields, 2018
Myrtill Simkó, Mats-Olof Mattsson
Several studies related to induction of nerve cell differentiation were discussed in Section 1.3.2. As a follow-up to earlier findings of the research group on induction of hippocampal neuronal differentiation after ELF-MF exposure, investigations of gene expression in neuronal stem cells were done (Leone et al. 2014). The cell cultures were exposed to a 50 Hz MF (1 mT, 2 days) after which a number of genes were studied with quantitative RT-PCR. Key genes such as the pro-proliferative gene HES1 and the neuronal determination genes NeuroD1 and Neurogenin1 were enhanced in expression levels after exposure, which was preceded by increased acetylation of the amino acid lysine in position 9 of the histone H3 and binding of the phosphorylated form of the transcription factor CREB to the promoter regions of the genes. This is another example of how ELF-MF influences epigenetic mechanisms. Interestingly, the effects on neuronal differentiation and also on histone acetylation were inhibited in the presence of the Ca2+-channel blocker nifedipine.
Introduction to Diffusive Processes
Published in Ranjit Kumar Upadhyay, Satteluri R. K. Iyengar, Spatial Dynamics and Pattern Formation in Biological Populations, 2021
Ranjit Kumar Upadhyay, Satteluri R. K. Iyengar
Stochastic RD simulations were successfully used in many biological applications. Some examples are the following: (i) models of signal transduction in E. Coli Chemotaxis [62], (ii) oscillation of Min proteins in cell division [25], (iii) MAPK pathway [106], (iv) intracellular calcium dynamics [29], (v) models of Hes1 gene regulatory network [103], and (vi) Actin dynamics in filopodia [23].
Existence and global exponential stability of almost periodic solutions of genetic regulatory networks with time-varying delays
Published in Journal of Experimental & Theoretical Artificial Intelligence, 2020
Lian Duan, Fengjun Di, Zengyun Wang
Many studies have revealed the fact that time delay is a common phenomenon in the processes of actual regulation, transcription, translation, diffusion, and translocation-especially in that of a eukaryotic cell. For instance, it has been proven in an important experiment on mice that there exists a time lag of about 15 min in the peaks between the mRNA molecules and the proteins of the gene hes1 (Hirata et al., 2002). For the gene her1 in zebra fish, it takes about 21 min from the initiation of transcription to the arrival of the mature mRNA molecule in the cytoplasm, and about 2.8 min from the initiation of translation to the emergence of a complete functional protein molecule (Lewis, 2003). In view of these facts, the discrete time-delay should be considered when modelling GRNs because each macromolecule takes the time to transfer from its place of synthesis to the location as described in Zhang, Tang, Wu, and Fang (2014); Wu (2011), and much research has been carried out on the stability analysis of delayed autonomous genetic regulatory networks have done in (Chen & Aihara, 2002; Koo, Ji, Won, & Park, 2012; Lakshmanan, Rihan, Rakkiyappan, & Park, 2014; Li, Chen, & Aihara, 2006; Li, Chen, Liu, & Zhao, 2016; Wang, Luo, Yang, & Cao, 2016; Wu, Liao, Feng, Guo, & Zhang, 2010) and the references therein.
Ozone ultrafine bubble water induces the cellular signaling involved in oxidative stress responses in human periodontal ligament fibroblasts
Published in Science and Technology of Advanced Materials, 2019
Anongwee Leewananthawet, Shinichi Arakawa, Tokuju Okano, Ryo Daitoku Kinoshita, Hiroshi Ashida, Yuichi Izumi, Toshihiko Suzuki
In RNA-seq analysis, we identified the several differentially expressed genes in OUFBW-treated cells. The most up-regulated metallothionein-1G is a member of intracellular cysteine-rich, metal-binding proteins. Metallothioneins are involved in the array of protective stress responses against various stimuli including oxidative stress [18]. The genes coding metallothioneins have many response elements for up-regulation of transcription in its promoter region that includes ARE. The transcription factor Nrf2 can bind ARE to induce cytoprotective responses to oxidative stress [16]. Therefore, the results suggest the possibility of Nrf2-mediated up-regulation of metallothioneins, which may play a role in protective stress responses against OUFBW stimulation. On the other hand, transcription factor HES1 has been reported to cooperate with retinoblastoma protein to activate transcription factor RUNX2, which is required for osteoblast differentiation and bone formation [22,23]. It may be possible that up-regulated HES1 is involved in osteoblast differentiation in periodontal ligaments. Furthermore, the c-Fos up-regulation in RNA-seq analysis is consistent with the activation MAPK pathway and the nuclear translocation of c-Fos in our study.