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.Characteristics of the actin gels aredetermined by the particular type of actin cross-linkers.Gels depolymerize back toliquid phase by calcium ions activating gelsolin protein which severs actin (jello tosoup).Actin repolymerizes into gel when calcium ion concentration is reduced (soupto jello).Actin gel, ordered water "jello" phases alternate with phases of liquid,disordered soup.Exchange of calcium ions between actin and microtubules (andmicrotubule-bound calmodulin) can mediate such cycles.Figure 3 Actin monomers self-assemble suddenly into filaments which form ameshwork.Lower left shows actin gel mesh encompassing hidden microtubules.The sol-gel transition is a very primitive biological phenomenon, related tomovement of single cells like amoeba or our own lymphocytes.In these cases theactin polymerzies in one direction, and liquefies behind it, causing a directionalflowing of cytoplasm.(Actin also polymerizes in response to light).In the 19thcentury Claude Bernard studied this phenomenon, which he called cytoplasmicstreaming, and discovered it was sensitively inhibited by exposure to the anestheticgas chloroform.In more complex, asymetrical cells like neurons, transport andmotion utilize polymerization of microtubules, though actin gelation still plays a role.Even in the "sol", or liquid phase, water within cells is not truly liquid and random.Pioneering work by Clegg (1984) and others have shown that water within cells is toa large extent "ordered," and plays the role of an active component rather than inertbackground solvent.Neutron diffraction studies indicate several layers of orderedwater on such surfaces, with several additional layers of partially ordered water. Protein-water binding/ordering is well studied, and linked to events in hydrophobicpockets on the protein interior.Wulf and Featherstone (1967) showed that anestheticbinding in a hydrophobic pocket altered the number of water molecules bound at theprotein surface.Water molecules bound to actin and other cytoskeletal surfaces, should also beordered and coupled to the actin/cytoskeletal dynamics.(See Scott Hagan scontribution for a description of quantum field theoretical approaches to the orderedstates of biological water).Watterson (1981, 1996) observes that in the conventionalview of gelation, long cross-linked polymer solutes form a spacious network.But inliving cytoplasmic gels, the water doesn't flow - even though the gel is over 75%water.NMR studies have shown that actin assembly results in reduced water mobility(ordering), and that distribution of ordered water through the cell is a heterogeneousand dynamic process.Pauser et al (1995) demonstrated that 55% of the water of thevegetal pole region of frog oocytes is bound water, with less bound (~25%) near theanimal pole cytoplasm, and ~10% bound in the nucleus.Ordered water distributionchanges in time also.For example cell cycle (mitosis) changes correlate with actinpolymerization, gelation, and reduced cytoplasmic water motion (Cameron et al,1987).The character of actin gelation and water ordering depends on actin cross-linking.Ofthe various cross-linker related types of gels, some are viscoelastic, but others (e.g.those induced by the actin cross-linker avidin) are solid and can be deformed by anapplied force without any response (Wacchstock et al, 1994).Such shock-absorbancewould be useful in quantum isolation.Cycles of actin gelation/solution can be quite rapid, occurring for example at 40 Hz.In neurons Miyamoto (1995) and Muallem et al (1995) have shown that cycles ofactin gelation/solution correlate with release of neurotransmitter vesicles from pre-synaptic axon terminals.I m unaware of any studies of sol-gel transitions in dendrites(a good literature review research question for any interested students!).So the environment is not necessarily wet, at least it s not wet some of the time.c.Is the environment noisy?Let's consider two types of noise: a) intracellular noise, presumably from thermalenergy of water, and b) electrical noise as manifest in electrophysiologicalrecordings.Several proposals have been put forth suggesting that thermal energy in biologicalsystems is somehow transformed into coherent excitations in biomolecules.MichaelConrad discussed "funneling" of thermal energy, and the Davydov soliton has beensuggested and discussed for many years.Perhaps the best known suggestion is that ofFrohlich
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Tematy
IndexAddison Wesley Programming for the Java Virtual Machine (1999)
Curtis A Keim Mistaking Africa, Curiosities and Inventions of the American Mind (2008)
Quantum Touch The Power to Heal 2nd Edit by Richard Gordon
Jiddu Krishnamurti 26 Collected Works 14 The New Mind
K.Kwiatkowski SURVIVAL po polsku 1999
K.Kwiatkowski SURVIVAL po polsku 1999(2)
Quantum Touch. The Power to Heal Richard Gordon
Chris Eisenlauer [Approaching The Blood Solution (epub)
1 Garwood Julie Róża
Chmiel Gugulska Katarzyna Syn Gondoru