Molecular communication

Ken Schaffner Just a very brief comment before we go on. About three years ago, I was doing some work on C. elegans, and I asked Corey Bargman about norms of reaction. She s a distinguished UCSF experimentalist. She said she had never heard about it. At least in that term. After I described what it was, she said oh wait, we use that . But she d never heard of the terminology, and I suspect that it s just not widespread in the molecular community. 

Kolattukudy PE, Kim Y, Li D, Liu ZM, Rogers L (2000) Early molecular communication between Colletotrichum gloeosporioides and its host. In Prusky D, Freemann S, Dickman MB (eds) Collelotrichum, Host specificity, pathology and host-pathogen interaction. American Phytopathological Society Press, St. Paul MN, p 78... 

Molecular communication is the characteristic information system in the bioinformation networks. The endocrine system, which is one of intermolecular information networks, may represent the feature of molecular communication. The gland is a collection of specialized cells that synthesize, store, and release hormones. A hormone, molecular information, is released into the extracellular fluid and transported via the blood to two types of cells target cells where the hormone acts, and other cells that degrade the hormone as schematically presented in Fig.l. In some systems the target cell and the degradation site are in the same organ or even the same cell. Both activities may even be located on the same plasma membrane. The receptor for the hormone is located on the surface of the plasma membrane. 

Another example of molecular communication is found in a neuronal synapse, which is a communication junction between two neurons as shown in Fig.2. The presynaptic membrane releases the neurotransmitter molecule that is recognized and captured by the receptor located on the surface of the postsynaptic membrane. 

Fig.l Schematic illustration of molecular communication in the endocrine system... 

In these molecular communications an information molecule is selectively recognized and transduced by the corresponding receptor which is a characteristic protein assembly found on the cellular membrane surface as schematically illustrated in Fig.3. Major categories based on its constitutions are... 

Molecular communication between the nucleus and the cytosol requires the movement of macromolecules through nuclear pores. RNA molecules synthesized in the nucleus are exported to the cytosol. Ribosomal proteins synthesized on cytosolic ribosomes are imported into the nucleus and assembled into 60S and 40S ribosomal subunits in the nucleolus completed subunits are then exported back to the cytosol. A variety of nuclear proteins (RNA and DNA polymerases, histones, topo-isomerases, proteins that regulate gene expression, and so forth) are synthesized in the cytosol and imported into the nucleus. This traffic is modulated by a complex system of molecular signals and transport proteins that is gradually being elucidated. 

Prestwich G. D. (1985) Molecular communication of insects. Quart. Rev. Biol. 60, 437-456. 

In OCT the conditional probabilities determining the molecular communication channel in the basis-function resolution follow from the quantum-mechanical superposition principle [51] supplemented by the "physical" projection onto the subspace of the system-occupied MOs, which determines... 

The purely molecular communication channel [9,38,46-48], with p defining its input signal, is devoid of any reference (history) of the chemical bond formation and generates the average noise index of the molecular IT bond covalency, measured by the conditional entropy S(b system outputs given inputs ... 

This quantity reflects the fraction of the initial (promolecular) information content H[p°], which has not been dissipated as noise in the molecular communication system. In particular, for the molecular input, when p° = p,... 

It should be emphasized that these entropy/information descriptors and the underlying probabilities depend on the selected basis set, for example, the canonical AO of the isolated atoms or the hybrid orbitals (HOs) of their promoted (valence) states, the localized MO (LMO), etc. In what follows we shall examine these IT descriptors of chemical bonds in illustrative model systems. The emphasis will be placed on the orbital decoupling in the molecular communication channels and the need for appropriate changes in their input probabilities, which weigh the contributions to the average information descriptors from each input. 

The molecular probability scattering in the specified diatomic fragment (A, B), involving AO contributed by these two bonded atoms, Xab = (xA, xB), to the overall basis set x = (Xxn is completely characterized by the corresponding P(XabIXab) block [22, 26] of the molecular conditional probability matrix of Eq. (4), which determines the molecular communication system in OCT [46-48] of the chemical bond ... 

R.F. Nalewajski, Molecular communication channels of model excited electron configurations, Mol. Phys. 104 (2006) 1977. 

R.F. Nalewajski, Information origins of the chemical bond Bond descriptors from molecular communication channels in orbital resolution, Int. J. Quantum. Chem. 109 (2009) 2495. 

Monolayers (2D films) can be regarded as ultimate thin states of organic and polymeric materials and are quite fascinating for constructing molecular amplification systems for the following reasons. First, the simplest (thinnest) structure of a monolayer allows one to comprehend the details of molecular communications and motions, because the excessive complexities of three-dimensional materials are efficiently excluded. This can lead to many implications on the material design of wide varieties of related systems. Second, for surface-mediated transfer processes, which consist of molecule-to-molecule transfer of information based on molecular orientations inscribed on uppermost surface layers, the existence of monolayers on material surfaces is sufficient for performances of macroscale controls of materials. Note that the nature and behavior of buried photochromic moieties in thicker films play minor roles. 

Since then, her focus has been on the cell biology of malaria in the mammalian liver. Her interests include sporozoite targeting to the liver, molecular communication between sporozoites and Kupffer cells, EE development in hepatocytes, mode of release and fate in the body of hepatic merozoites, and the comparative biology of the exo-erythrocytic phase of mammalian and avian malaria infections. Establishment of the methodology to observe fluorescent parasites in various organs of live animals has provided a window into the complex life cycle of Plasmodium in the mammalian host. 

This entropic approach to bonded fragments in a molecule has created a new impetus to a search for novel, information-distance measures of the chemical bond multiplicities [27,28]. The resulting entropic bond-orders reflect upon the molecular communication system involving the promolecular input probability scheme and the molecular output probability scheme, of finding electrons on specified AIM. Clearly, the promolecule probabilities of atomic assignments are modified in a molecule as a result of the communication noise created by the electron delocalization throughout the molecular system, via a network of the chemical bonds. Specific entropy differences have been found to reflect both the global and... 

However, in other areas DCC has expanded well beyond what it was originally conceived to do. When regarding DCLs not merely as discovery tools, but as molecular networks, many additional opportunities present themselves, some of which are now starting to be explored. A nice example includes the use of multiphase systems recently reported by Sanders et al. [28] We expect that the future will bring many new developments in new areas, which may include emergent behavior such as information processing [16], feedback behavior, and molecular communication. 

The point locations arrive by an elementary view of molecular communication in thermal environments. 

FIGURE 6.2 Molecular communication revisited. Colliding CH4 and N2 demonstrate multiple trajectories and interaction potentials. 

To keep the focus on thermodynamics, one looks again at the ABA nature of molecules—assemblies of C-C, C-H, and so on. One further keeps in mind the lessons of Figures 6.1 and 6.2, namely, that molecular communication occurs by thermal collisions. 

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