ULTIMATE COMPUTING - Quantum Consciousness Studies

96 Cytoskeleton/Cytocomputer
Figure 5.11: Microtubules in PtK2 cells illustrated by tubulin antibody at two
different magnifications. Nucleus (left) is devoid of MT, which densely emanate
from nearby MTOC. With permission from Geuens, Gundersen, Nuydens,
Cornellisen, Bulinski, and DeBrabander (1986).
As the chromosomes condense in prophase, the MT system changes its
display and turnover rate. Interphase MT are gradually shortened while new MT
start to grow from the centrosome. At this point, the system is extremely sensitive
to polymerization inhibitors. Drugs which are used against cancer are often
mitotic inhibitors which prevent the rapid polymerization of prophase MT from
MTOC. Kinetochores are mobile MTOC which attach chromosomes and bind MT
at their plus end (Figure 5.10). MT assemble between centrosomes (which bind
their minus end) and kinetochores (which bind their plus end) and separate the
genetic material towards the daughter cell poles in the mitotic cycle. The delicate
array of the two centrioles, connected MT spindles and “star-like astral
projections” (MT which “overshoot” the centrioles) have suggested to many
observers some type of electromagnetic field because of the resemblance to a
magnetic field pattern. The contractile ring formed perpendicular to the axis of
mitosis by the microtrabecular lattice establishes a cleavage furrow which
separates the daughter cells. The chromosome material decondenses while a new
nuclear membrane is zipped onto it, and cellular elements assume again an
organized aspect. Later, the cells flatten and gradually reassume their normal
interphase shape.