Intelligence in the Cytoskeleton

Cytoskeletal gel networks have complex repertoires. Motile events within non-repetitive muscle cells are dynamic, often transient and variable and not strictly analogous to muscle contraction. Cells contain from two to five different types of actin and these may combine up to ten different ways depending on the presence of binding proteins and other factors. Certain actins polymerize in the presence of calcium or magnesium ions whereas other actins polymerize only in their absence. Non-muscle cells possess control mechanisms that dynamically switch between monomeric actin, actin in a filamentous bundle form, and actin in a geodesic gel meshwork form. Some cytoplasmic motility is the result of actin myosin crawling, whereas examples depend on explosive polymerization of actin, rapid disaggregation of actin filaments, or interconversion of filament bundles into a meshwork (Satir, 1984). Microtubules, filaments, and centrioles are also involved in these same aspects of cell movement and are particularly important to orientation and directional guidance.

How can these diverse modes be coordinated? Guenter Albrecht-Buehler (1985) cites two basic requirements for cytoplasmic intelligence. These are compartmentalization, which separates components engaged in various functions to prevent chaos, and the information content. According to Shannon (1948) information is not concerned with the meaning of the message but only with its formal structure. As Marshal MacLuhan said: "the medium is the message"; the cytoplasm is both!

Information can have spatial and temporal content: spatially a message can be in the form of a letter or magnetic tape, and/or can have a temporal structure such as a radio signal or movie. It is the very coupling of spatial and temporal components in a dynamic sense that provides the medium of information. Shannon suggested that intended signals be "unpredictable." For example, a meaningful text is a sequence of words and letters that the reader cannot anticipate. In contrast, text consisting of an uninterrupted string of a single letter doesn't carry much information. Similarly in temporal messages such as radio signals, the strictly periodic and therefore predictable carrier wave of a transmitter carries no information. Only after the periodic oscillations of the carrier wave have been modulated with unpredictable changes of frequency (FM), or amplitude (AM) can speech or music be heard. At the opposite end of the spectrum, random stochastic noise is equally devoid of information.

Albrecht-Buehler observes that cytoplasm is neither totally regular, like a periodic crystal, nor totally random like a boiling liquid, but is an organized piece of matter. Complex, intricate activities occur "in the midst of drowning thermal noise all around and within." The cytoplasm not only keeps its cool against the thermal background, it routinely couples spatial and temporal components to manifest information. One example of cytoplsamic information which is independent of DNA/genetic control is the pattern of ciliary orientation in paramecium (Figure 5.27). Extrinsically altered, "nongenetic" patterns are maintained through one hundred mitotic generations (Aufderheide, Frankel and Williams, 1977).

Albrecht-Buehler describes three possible and progressively enlightened approximations to account for the intelligent actions of cytoplasm. 1) "The secret of cytoplasmic complexity is sought in the very randomness of thermal chaos combined with the observed specificity of biochemical reactions." This view is doubtful since the cytoskeleton and other structures take on elaborate, nonrandom forms. 2) Cytoplasmic intelligence stems from "supramolecular topology, architecture and dynamics rather than freely swarming inhibitors and promoters with their competing binding constants." The complex spatial arrangements of protein subunits and other molecules in macromolecular assemblies strongly suggests cooperativity between biochemical events over large intracellular distances. This leads to consideration of cytoplasm as a "giant multienzyme complex" based on cooperative actions of actin, IF, and MT. This implies an automatic, robot-like machine function of the cytoplasm, presumably set in motion and directed by the genetic apparatus. This view is embraced by many biologists who deify DNA as the prime mover in all biological activities and neglect the "real time" cytoplasmic activities of organisms. 3) Albrecht-Buehler suggests an inherent intelligence within cytoplasm. Intelligence implies the ability to collect and process data and make decisions on the basis of these data. Also important are intrinsic criteria that distinguish between desirable and nondesirable outcomes. Intelligence implies the ability to assess global situations, not merely reacting to local stimuli whenever and wherever they occur, and it implies communication of data with other intelligent objects and appropriate adjustment of actions. Albrecht-Buehler suspects that computers were discovered, rather than invented, and that cytoplasm is a "chemistry based gel or even liquid data processing system."

Cytoplasmic intelligence may depend on collective dynamics of cytoskeletal subunits. Parallel arrays of MT and neurofilaments provide a framework around which microtrabecular lattice structures could form with varying durations of existence as correlates of learning, information, memory, and consciousness. Mechanical contractility of actin-myosin and other proteins within the cytomusculature/cytomatrix could impart mechanical vibrations and cooperative resonances, solitons, or interference wave patterns. Geodesic tensegrity nets of MT, actin and their ordered water may be pulsating in the nanoscale at this very moment within all living cells. Polymerization patterns of actin and other proteins may also be regulated by calcium induced sol-gel state phase differences or harmonic coupling with other microtrabecular and cytoskeletal structures. Coherent nanosecond excitations and propagating solitons are additional mechanisms which have been proposed to occur within the cytoskeleton. In the brain, reinforcement from higher levels of parallel processing (neuron level, neural net, brain) could fortify specific substructures such as wave patterns of calcium coupled sol-gel states in neural cytoplasm.

The "genetic code" was decrypted by Marshal Nirenberg and colleagues (1961, 1964) who were able to equate DNA base pair patterns with specific amino .acid sequences in synthesized proteins. The "real time" information codes in the cytoskeleton may be understood when cytoskeletal nanoscale events just beyond our current capabilities become approachable with the advent of nanotechnology in the next decades.

Figure 5.27: Paramecium mitosis and cytoskeletal "heredity." Top: a single Paramecium elongates and divides into two daughter cells. The surface of Paramecium are covered with hair-like cilia, each of which is a collective assembly of microtubule doublets or triplets. Cilia bend cooperatively to propel the Paramecium, and to propel liquid environment past the organisms. All the cilia are oriented in the same direction, to the left. Second row: Experiments done by Aufderheide, Frankel and Williams (1977) are illustrated. A segment of cell membrane and underlying cytoskeleton which anchors cilia is transplanted in reverse orientation to a sister paramecium. The abnormal cilia orientation persists in the next generation, and for 100 generations to follow! By Paul Jablonka.

Figure 5.27: Paramecium mitosis and cytoskeletal "heredity." Top: a single Paramecium elongates and divides into two daughter cells. The surface of Paramecium are covered with hair-like cilia, each of which is a collective assembly of microtubule doublets or triplets. Cilia bend cooperatively to propel the Paramecium, and to propel liquid environment past the organisms. All the cilia are oriented in the same direction, to the left. Second row: Experiments done by Aufderheide, Frankel and Williams (1977) are illustrated. A segment of cell membrane and underlying cytoskeleton which anchors cilia is transplanted in reverse orientation to a sister paramecium. The abnormal cilia orientation persists in the next generation, and for 100 generations to follow! By Paul Jablonka.

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