275 research outputs found
Algebraic and Topological Indices of Molecular Pathway Networks in Human Cancers
Protein-protein interaction networks associated with diseases have gained
prominence as an area of research. We investigate algebraic and topological
indices for protein-protein interaction networks of 11 human cancers derived
from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. We find a
strong correlation between relative automorphism group sizes and topological
network complexities on the one hand and five year survival probabilities on
the other hand. Moreover, we identify several protein families (e.g. PIK, ITG,
AKT families) that are repeated motifs in many of the cancer pathways.
Interestingly, these sources of symmetry are often central rather than
peripheral. Our results can aide in identification of promising targets for
anti-cancer drugs. Beyond that, we provide a unifying framework to study
protein-protein interaction networks of families of related diseases (e.g.
neurodegenerative diseases, viral diseases, substance abuse disorders).Comment: 15 pages, 4 figure
The Bioelectric Circuitry of the Cell
This chapter presents an overview of electric conduction in living cells when viewed as a composition of bioelectric circuits. We review the cell's components that are known to exhibit electric conduction properties and represent them as parts of a complex circuitry. In particular, we discuss conductivity of the membrane, ion channels, actin filaments, DNA, and microtubules, each of which play important roles in the biological functioning of the cell. A new picture emerges where electrical conduction within the cell is taking place in an integrated fashion and may explain synchronization and orchestration of the cell dynamics
Model of ionic currents through microtubule nanopores and the lumen
It has been suggested that microtubules and other cytoskeletal filaments may
act as electrical transmission lines. An electrical circuit model of the
microtubule is constructed incorporating features of its cylindrical structure
with nanopores in its walls. This model is used to study how ionic conductance
along the lumen is affected by flux through the nanopores when an external
potential is applied across its two ends. Based on the results of Brownian
dynamics simulations, the nanopores were found to have asymmetric inner and
outer conductances, manifested as nonlinear IV curves. Our simulations indicate
that a combination of this asymmetry and an internal voltage source arising
from the motion of the C-terminal tails causes a net current to be pumped
across the microtubule wall and propagate down the microtubule through the
lumen. This effect is demonstrated to enhance and add directly to the
longitudinal current through the lumen resulting from an external voltage
source, and could be significant in amplifying low-intensity endogenous
currents within the cellular environment or as a nano-bioelectronic device.Comment: 43 pages, 6 figures, revised versio
Quantum paradigms in psychopathology: multiscale investigations from biomolecular qubits to the brain, and its pathological states
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Cancer proliferation and therapy: the Warburg effect and quantum metabolism
Background: Most cancer cells, in contrast to normal differentiated cells, rely on aerobic glycolysis instead of oxidative phosphorylation to generate metabolic energy, a phenomenon called the Warburg effect. Model: Quantum metabolism is an analytic theory of metabolic regulation which exploits the methodology of quantum mechanics to derive allometric rules relating cellular metabolic rate and cell size. This theory explains differences in the metabolic rates of cells utilizing OxPhos and cells utilizing glycolysis. This article appeals to an analytic relation between metabolic rate and evolutionary entropy - a demographic measure of Darwinian fitness - to: (a) provide an evolutionary rationale for the Warburg effect, and (b) propose methods based on entropic principles of natural selection for regulating the incidence of OxPhos and glycolysis in cancer cells. Conclusion: The regulatory interventions proposed on the basis of quantum metabolism have applications in therapeutic strategies to combat cancer. These procedures, based on metabolic regulation, are non-invasive, and complement the standard therapeutic methods involving radiation and chemotherapyMolecular and Cellular Biolog
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