Cytoplasmic Gel States and Ordered Water: 
Possible Roles in Biological Quantum Coherence

Abstract

Water inside living cell cytoplasm fluctuates between phases of disordered liquid (solution: "sol") and ordered solid (gelatinous: "gel") determined by polymerization of the actin cytoskeleton. Cycles of sol-gel transformations are important in fundamental cellular processes (movement, growth, mitosis, synapse formation, etc.) and are regulated by calcium, which in turn may be regulated by other cytoskeletal structures such as microtubules. Sol-gel transformations are close to the nature of life, and of consciousness enigmatic phenomena for which quantum coherence has been suggested as an explanatory mechanism.

In a quantum coherent system which remains isolated from its environment, spatially distributed components can exist in coherent "superposition" of many possible states. This property may explain the unity of biological functions in a living cell, and of consciousness throughout macroscopic portions of the brain.

The possibility of quantum coherence in biology is often discounted because the disordered water environment is assumed to dissipate any coherence. However, ordered water coupled to the cytoskeleton may become part of its quantum state. This paper argues that cycles of sol-gel transformation in living cells correspond to cycles of dissipation (sol) and isolation (gel) of quantum coherence in microtubules and cytoplasm. Three models of biological quantum coherence depending on actin gels and ordered water are discussed: 1) super-radiance in microtubules [1]; 2) cellular vision [2]; 3) orchestrated objective reduction in microtubules [3].

1: Introduction

What is the character of "living" water? Is there a fundamental difference between water within living biological cells ("cytoplasmic water") and other types of water?

Pioneering work by Clegg [4] and others have suggested that water within cells is to a large extent "ordered," and plays the role of an active component rather than inert background solvent. That is, intracellular water molecules are bound to surfaces within cells, and coupled to the dynamics of those surfaces. Surface-bound water supports further layering of ordered water, so that a significant proportion of cytoplasmic water may be ordered. The greatest source of water-ordering surfaces within cells is the cytoskeleton.

The cytoskeleton within living cells provides structure and organization for dynamical biological processes. Anumber of authors have proposed various types of information processing mechanisms occurring in the cytoskeleton [5-9]. Three types of protein filamentous structures comprise the cytoskeleton: microtubules, actin filaments, and intermediate (keratin) filaments. Of these, actin seems to play the greatest role in binding and ordering water.

Cytoplasm exists in phases of "sol" (solution, or liquid), and "gel" (gelatinous phases of various sorts). Transition between sol and gel phases depends on actin polymerization. Triggered by changes in calcium ion concentration, actin co-polymerizes with different types of "actin cross-linking proteins" to form microfilaments and various types of gels. Characteristics of the actin gels are determined by the particular type of actin cross-linkers. Gels depolymerize back to liquid phase by calcium ions activating gelsolin protein which severs actin. Actin repolymerizes into gel when calcium ion concentration is reduced. Actin gel (ordered water) phases cycle with phases of liquid cytoplasm and disordered water. Exchange of calcium ions between actin and microtubules (and microtubule-bound calmodulin) can mediate such cycles [10]. Microtubule exteriors apparently do not bind and order water [11].

NMR studies have shown that actin assembly results in reduced water mobility (ordering), and that distribution of ordered water through the cell is a heterogeneous and dynamic process. Pauser et al [12] demonstrated that 55% of the water of the vegetal pole region of frog oocytes is bound water, with less bound (~25%) near the animal pole cytoplasm, and ~10% bound in the nucleus. Ordered water distribution changes in time also. For example cell cycle (mitosis) changes correlate with actin polymerization, gelation, and reduced cytoplasmic water motion [13]. Cycles of actin gelation/solution can be quite rapid. Miyamoto [14] and Muallem et al [15] have shown that cycles of actin gelation/solution correlate with release of neurotransmitter vesicles from pre-synaptic axon terminals. Sol-gel dynamics may be important in neural function.

The character of actin gelation and water ordering depends on actin cross-linking. Of the 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 an applied force without any response [16].

Watterson [17-18] observes that in the conventional view of gelation [19], long cross-linked polymer solutes form a spacious network. But in living cytoplasmic gels, the water doesn't flow - even though the gel is over 75% water. Watterson argues that each protein (e.g. primarily actin subunits) stabilizes water in a specific volume, and that these "water clusters" form stable 3-dimensional assemblies (Figure 1).

The volume of each of Watterson's water clusters ("pixels") is about 40 cubic manometers. The corresponding length scale of 3 to 4 nanometers is near the limit for quantum tunneling. Kaivarainen [20] views these elements as structural quanta; many such quanta can fuse to produce higher level macroscopic quantum states.

Figure 1. The Watterson Gel State (from Watterson, 1996) Although up to 80% water, this solid-like material is produced by cooperativity among clusters. Proteins are like compact "twisted barrels," with the basic pixel size, 40 cubic nanometers. The proteins order adjacent water. Actin assembly into filamentous chains results in a phase transition of bound water clusters.

2: Quantum Coherence in Cytoplasm?

Actin gelation and microtubule assembly produce cytoplasmic rearrangements such as amoeboid movements, mitosis and cleavage, neurite growth and synaptic formation. The regulation and control of these self-organizing behaviors are not well understood. There is some suggestion that quantum coherence is involved in living matter, and in consciousness [3,21,22].

Herbert Frohlich, an early contributor to the understanding of superconductivity, also predicted quantum coherence in living cells (based on earlier work by Oliver Penrose and Lars Onsager [23]) Frohlich [24-26] theorized that sets of protein dipoles in a common electromagnetic field (e.g. proteins within a polarized membrane, subunits within an electret polymer like microtubules) undergo coherent conformational excitations if energy is supplied. Frohlich postulated that biochemical and thermal energy from the surrounding "heat bath" provides such energy. Cooperative, organized processes leading to coherent excitations emerged, according to Frohlich, because of structural coherence of hydrophobic dipoles in a common voltage gradient.

Coherent excitation frequencies on the order of 109 to 1011 Hz (identical to the time domain for functional protein conformational changes, and in the microwave or gigaHz spectral region) were deduced by Fr hlich who termed them acousto-conformational transitions, or coherent (pumped) phonons. Such coherent states are termed Bose-Einstein condensates in quantum physics and have been suggested by Marshall [27] to provide macroscopic quantum states which support the unitary binding of consciousness.

Experimental evidence for Frohlich-like coherent excitations in biological systems includes observation of gigaHz-range phonons in proteins [28], sharp-resonant non-thermal effects of microwave irradiation on living cells [29], gigaHz induced activation of microtubule pinocytosis in rat brain [30], and laser Raman spectroscopy detection of Frohlich frequency energy [31-32]. Coherent Frohlich excitations in cytoskeletal microtubules have been suggested to mediate information processing [5,7,9].

Related work has focused on water at the surfaces of quantum coherent biostructures. In the context of quantum field theory, an historical line of theoretical proposals [33-35] have examined interactions between the electric dipole field of water and the quantized electromagnetic field of the (cytoskeletal) biostructure.

In quantum field theory, fundamental fields fill the universe. Constituents of matter (electrons, protons, neutrons) are seen as the energy quanta of the matter field, which interacts with the quantum electromagnetic field by exchanging, creating and annihilating photons. ("Our world is made of matter and light" - [35]) The significant point for biology and neuroscience is that the allowed energy states ("eigenstates") of a quantum field are mutually correlated with other energy eigenstates. A quantum field is thus coherent, unitary, and avoids thermal disorder. Such properties characterize life, and consciousness.

Jibu and Yasue [35] have specified "Quantum Brain Dynamics" (QBD) in which the quantized electromagnetic field interacts with the rotational field of water molecule dipoles within neural dendrites and glia. Lowest energy eigenstates ("ground," or "vacuum" states) of the water dipole field are memory states in QBD. The dynamic exchange - creation and annihilation of quasi-particles ("corticons") between the two fields - is consciousness, in the Jibu/Yasue view, and is proposed to interface to cytoskeletal dynamics which in turn interface with dendritic and neural network levels of brain function.

Here we consider three proposals in which ordered water may play a role in biological quantum coherence essential for living systems and consciousness: 1) quantum optical coherence in microtubule inner cores ("super-radiance" and "self-induced transparency"); 2) cellular "vision"; 3) isolation of microtubules from environmental decoherence.

2a: Super-radiance in Microtubule Inner Cores

Microtubules are hollow cylinders. Jibu et al [32] considered the water within the hollow inner core of microtubules in "Frohlich" quantum coherence (cf. [36]). Specifically, the quantum dynamical system of watermolecules and the quantized electromagnetic field confined inside the hollow microtubule core manifest a specific collective dynamics called "superradiance" by which the microtubule can transform any incoherent, i.e., thermal, and disordered molecular, electromagnetic, or atomic energy into coherent photons inside the microtubules (Figure 2).

Analogous to superconductivity, Jibu and Yasue further suggest that such coherent photons created by superradiance penetrate perfectly along the internal hollow core as if the optical medium were made transparent by the propagating photons themselves. This is a quantum theoretical phenomenon called "self-induced transparency."

2b: Cellular Vision

When exposed to light, simple cells such as amoebae undergo a diffuse actin-based sol-gel transformation. To investigate rudimentary vision at the level of individual cells, Albrecht-Buehler [37-38] showed that 3T3 fibroblasts approached distant visible or infra-red light spots. The cells produced amoeboid pseudopodia (via actin-gel assembly) which extended toward the light

Figure 2. Jibu, Yasue and Hagan Super-radiance in Microtubules (from Jibu et al, 1994). A schematic representation of the process of super-radiance in a microtubule. Each oval without an arrow stands for water molecule in the lowest rotational energy state. Each oval with an arrow stands for a water molecule in the first excited rotational energy state. The process is cyclic (a b c d a b . ..), and so on. (a) Initial state of the system of water molecules in a microtubule. Energy gain due to the thermal fluctuation of tubulins increases the number of water molecules in the first excited rotational energy state. (b) A collective mode of the system of water molecules in rotationally excited states. A long-range coherence is achieved inside a microtubule by means of spontaneous symmetry breaking. (c) A collective mode of the system of water molecules in rotationally excited states loses its energy collectively, and creates coherent photons in the quantized electromagnetic field inside a microtubule. (d) Water molecules, having lost their first excited rotational energies by super-radiance, start again to gain energy from the thermal fluctuations of tubulins, and the system of water molecules recover the initial state (a). spot, and initiated movement. Albrecht-Buehler further showed that the light-sensitive organelle perceiving direction is the microtubule-based centriole (a pair of microtubule mega-cylinders) within the cell near the nucleus. Jibu and Yasue [2] have argued that the electromagnetic signaling from the distant light spot reaching the centriole consists of "evanescent" photons tunneling through dynamically ordered regions of cell water.

2c: Isolation in "Orch OR"

In a specific model of consciousness based on microtubule quantum coherent superposition and self-collapse ("orchestrated objective reduction"), Hameroff and Penrose [3,21,22] have shown the necessity for isolation of microtubule quantum coherence from environmental decoherence [39]. For a quantum state to persist, it must be isolated from its environment to avoid dissipation and decoherence. However for the information gained in the quantum self-collapse process to be useful, it must also communicate with the environment. A possible solution [10] is that cycles of alternating isolation and communication occur. Cycles of actin gelation (and water ordering) occur in conjunction with neurotransmitter vesicle release in the axon terminal [14,15]. Cycles of actin gelation in neural dendrites, for example, coupled to membrane activities could serve to cyclically isolate quantum coherence in microtubules from environmental decoherence. However this appears somewhat paradoxical: if actin gelation and associated water-ordering facilitate quantum coherence in the cellular vision case described above, can they also isolate quantum coherence in microtubules? There are several possible scenarios: 1) a specific type of actin cross-linker gel may shield quantum coherence, whereas another may enable it, 2) actin gelation/water ordering may allow the entire cytoplasm to become quantum coherent (and linked to quantum coherence in other cells by gap junctions [e.g., 40].

3: Conclusion

Cytoplasmic water has unique characteristics related to being a major component of a living organism - the water is somehow alive. But how? Layers of ordered water coupled to cytoskeletal surfaces may enable quantum coherence in cytoplasm - a phenomenon closely related to life, and consciousness.

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