3T3 cells Fibroblasts from a Swiss mouse embryo isolated more than 30 years ago by Howard Green and George Todaro and ever since kept growing in tissue culture as a permanent cell line.
centrioles Centrioles are a pair of small cylinders (0.5 µm x 0.2 µm) oriented perpendicular to each other and located inside the centrosphere adjacent to the nucleus. During mitosis cells place them at the spindle poles. Therefore, only eukaryotic cells may have centrioles. They are found predominantly in animal cells, while most plant cells do not have centrioles. However, both plant and animal cells can make them de novo if they differentiate into migrating cells. For example, human cells have no centrioles during early embryonic development. The fertilized human egg has no centrioles and continues to divide until gastrulation begins and with it the massive migration of cells from the mesoderm. At that point every cell equips itself with a pair of centrioles. Therefore, the frequently copied statement from textbooks that centrioles organize mitotic spindles is wrong: Plant cells and early human cells have perfect mitotic spindles, but no centrioles. We believe that centrioles are the 'eyes' of cells [See ref 9,ref 14,ref 16]
centrosome Discovered and named by early cytologists as an organelle-free spherical area near the nucleus of a cell. It is associated with the Golgi apparatus and contains the pair of centrioles in animal cells. In interphase cells the microtubules radiate unbranchingly from the centrosome to the cell cortex. In dividing cells the centrosome organizes the spindle poles from which the spindle microtubules radiate unbranchingly to the chromosomes. Fertilization requires the passing on of centrioles to the zygote. It is one of the most mysterious parts of the cell. Daniel Mazia considers centrosomes "the bearer of information about the cell morphology". We would like to go further and consider the centrosome as the 'brain' of the cell.
centrosphere(see centrosome)
cortex A dense layer of contractile proteins (actin, myosin, etc.) right underneath the plasma membrane. It executes changes of cell shape and generates the major types of motile surface projections (pseudopodia) such as filopodia, lamellipoia, and blebs.
cytoskeleton A network of 3 types of protein polymers, namely the microtubules, the intermediate filaments and the microfilaments. It also contains numerous proteins that are associated with the fibrous polymers. They nucleate, bundle, cap and link the fibers with each other, with cell organelles and the plasma membrane. It is the mechanical and functional framework for every known cellular function.
cytoplasmic asters The radial array of microtubules of interphase cells with the centrosome at its center. The cytoplasmic asters are distinct from the mitotic asters that radiate from the spindle poles of a dividing cell. In the context of our research we mean specifically radial arrays of microtubules that were regenerated after an anti-microtubular drug had disassembled the original array of microtubules.
emergence The phenomenon that the whole may be more than the sum of its parts ('1+1>2'). For example, flight is an emergent property of all the mechanical parts of an airplane: None of the parts can fly, but the whole of the parts can. Applying this concept to 'intelligence' one may claim that intelligence is an emergent property: ....the level of cell intelligence emerges from the intelligence of cell compartments.The level of organism intelligence emerges from intelligent cells. The level of intelligence displayed by entire populations emerges from intelligent organisms. The level of intelligence of an ecology emerges from the intelligence of its populations... and so forth.
fractal The structural property of an object that consists of self-similar parts. In other words, the parts are smaller copies of the object. So are the parts of the parts, and so forth ad infinitum.
intermediate filaments One of the 3 cytoskeletal fiber types. They have a diameter of 10 nm and are composed of a large family of proteins. A subset of intermediate filaments are also known a keratin fibers which give skin and hair their mechanical strength.
lysosomes Organelles that contain lytic enzymes. They represent the 'digestive' system of cells.
microplast Microplasts are fragments of cells that remain alive for many hours.They come in various sizes. The smallest contain about 2% of a cell volume and consist mostly of cortex surrounded by a plasma membrane. Their movements are autonomous, but restricted to the universally observed shape changes such as spreading, attaching, ruffling, blebbing, waving of filopodia etc. Unlike whole cells they cannot move their entire body to another location after they were forced to round up and respread. This procedure destroys all directional properties that might have been left in their bodies from their parental cell. Microplasts cannot restore or create directionality of movement.
microtubules One of the 3 cytoskeletal fibers. They have a diameter of 24 nm and appear to be hollow tubes, although there are cases where they are filled with an unknown substance.They are composed of two proteins and appear prominently in mitotic spindles. In interphase, they form cytoplasmic asters. The blades of centrioles are composed of microtubules. Our research suggests that they are the 'nerves' of the cells.
mitochondria The 'power supplies' of cells. In phase contrast microscopy they appear as squiggly lines. They 'swim' in a snake-like fashion autonomously through the cytoplasm. They divide autonomously because they are the only cellular compartment with its own DNA that, however, that DNA is not a complete genome. Another part of their genome is contained in the cell's nucleus requiring a remarkable level of co-operation between the two.
nucleus From the point of view of the 'intelligent cell' the nucleus is the main library. It contains the blueprints and instructions that have evolved over one billion years of evolution, which tell the cell how to operate, how to rebuild itself (including its 'nerves' and 'brain') after every cell division, and how to act and interact with other cells as they build and maintain an organism. Topologically speaking, the nucleus is located outside the cell because there is a closed surface between it and the cytoplasm. This surface is not entirely closed, though, because it is pierced by so-called nuclear pore complexes.
But there is more. Its gene control systems handles huge numbers of signals that arise from within the nucleus and from its outside word, the cytoplasm. It seems to be structured as a hierarchy of levels of genomic instructions. Starting with genes which constitute the most basic level, transposons may belong to a meta-level in the sense that they represent instructions for genes. There may be a meta-meta-level of 'itinerons' that determine the destinations of transposons, and so forth.
In short, the nucleus, far from being a 'dumb' library of the intelligent cell, is clearly an intelligent system in its own rights. We may be seeing here the first glimpse that intelligence is a fractal property: Intelligent ecologies contain intelligent populations,which contain intelligent organisms, which contain intelligent cells, which contain intelligent compartments, which contain...and so forth.
plasma membrane The 'skin' of the cell that transmits materials and sensory signals beween the inside of the cell and its outside world.
phagokinetic tracks A biological 'cloud chamber' that allows cells to record their own movements in the form of tracks that they leave in a carpet of tiny gold particles on the substrate. [See examples and ref 1, ref 2, ref 4 ]
pseudopodium A motile and ephemeral surface projection out of the cortex of a cell. Examples are filopodia, lamellipodia and blebs.
ruffle A lamellipodium in the process of folding back onto the cell body from which it extended earlier. Seen from the side, ruffles are straight like pencils that swivel around one end near the substrate.
tail The rear part of a migrating cell which usually has a pointed shape that retracts to the body every so often during locomotion [See example]. Both front and tail of a migrating cell are expressions of its so-called polarity. Polarity, in turn, is the expression of the remarkable ability of a cell to turn its initially undirectional body into a directional (vectorial) shape in and out of itself. Mathematicians would call this turning of a scalar into a vector a violation of the Curie principle which is presumably another hint that cells have information-processing abilities.