ULTIMATE COMPUTING - Quantum Consciousness Studies

Models of Cytoskeletal Computing 165
MT which comprise the axopod are explained by inter MT bridges of two
different lengths. The authors considered that these two types of linkages can not
only account for the complex structure of the axopod, but also indicate two
different conformational states of the tubulin dimers to which the bridges attach.
Along the lengths of the axopod, microtubule linkages are found at intervals that
reflect binding at approximately every fourth dimer. These precise linkage sites
represented a code of some sort to Roth, Pihlaja, and Shigenaka who proposed in
1970 that recurrent patterns, or “gradients” existed in microtubules to localize
these precise binding patterns. They defined these patterns as “gradions”:
repeating conformational sequences or fields in which multiple varying patterns
can exist in the same molecular architecture simultaneously.
Figure 8.3: “Gradions” within microtubule lattice. Dark shaded dimers are MAP
attachment patterns; numbered dimers are determined by proximity to MAP
attachment sites. MAP binding and other “gradionators” are thought to induce
coded patterns representing information. From Roth, Pihlaja and Shigenaka
(1970) by Paul Jablonka.
Conformational states of individual tubulin subunits were thought to be
controlled by factors Roth, Pihlaja, and Shigenaka termed “gradionators.” These
could include ligand induced conformation, tubulin isozyme, detyrosination, or
binding of MAPs including inter-microtubule bridges. They defined discrete