Location of the cellular 'eye'

[See ref 16 ]

Cells cannot reach out to a light source if their center is illuminated with the same light (center-irradiation).

According to our hypothesis the centrioles mediate the extension of surface extension towards infrared light sources. Therefore, it should be possible to 'blind' cells temporarily by shining the same light into their center that illuminates the scattering particle nearby with a second beam of the same intensity and wavelength. Such treatment does not cause any detectable damage to the cells as indicated by their normal motile behavior once the light to their center is turned off. The experiments showed, indeed, that cellular extensions towards nearby light sources are inhibited as long as its center is irradiated by a second beam of the same wavelength, intensity and pulse frequency.

Cells remain able to reach out to a light source if a spot next to their center is illuminated with the same light (peripheral irradiation).

In contrast, cells remained capable of reaching out to the light source nearby if the second light beam hit them a few micrometers away from the cell center. Both results together suggest that the cellular infrared 'eye' is located in the cell center and must be one of the cellular components that are located in the cell center but nowhere else. The obvious candidates for such structures are the nucleus, the Golgi-apparatus and the centrosome. The following experiments exclude all candidates except the centrosome.

Centrosomal location of the cellular 'eye' (exclusion of nucleus as 'eye'): Cells can still reach out to a light source after enucleation.

In order to test whether the nucleus was required for cellular infrared 'vision' cytoplasts were produced by incubation in cytochalasin B followed by centrifugation. Among 20 experiments with enucleated cells 4 picked up the light scattering particle. Since only one was needed to disprove the assumption that the nucleus was the infrared sensing mechanism, we did not carry out a larger number of experiments. Therefore, only the Golgi-apparatus and the centrosome are left as candidates for the infrared 'eye'.

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Centrosomal location of the cellular 'eye' (exclusion of the Golgi apparatus as 'eye'): Cells can still to reach out to a light source after destruction of their Golgi-apparatus.

In order to test whether a functional Golgi-apparatus was required for cellular infrared 'vision' we incubated 3T3 cells overnight in 0.15 µM monensin. This treatment vesiculates their Golgi-apparatus and inhibit their Golgi functions. Yet, among 9 monensin-treated cells we found 4 that reached over to the particle. The results suggest that the ability of 3T3 cells to detect and extend surface projections to infrared light scattering particles nearby does not require the presence of a functional nucleus or Golgi-apparatus. Therefore, only the centrosome remains as an exclusively central cell organelle that may contain the infrared sensing component(s) of the cell center.

Significance for cell intelligence:

The centrosome may be the 'brain' of a cell.
Finding the cellular 'eyes' is not the ultimate goal of this project; Finding the cellular data integration system is. In organism the two are always physically connected. Perhaps that is also true for cells. The most obvious cellular compartent to which the centrioles are physically connected is the centrosome. There are other reasons to suspect that the centrosome may be the cellular data integration system. For example, it forms the center of an array of microtubules that terminate in the cellular cortex which projects the cellular extensions that reach out to the infrared light sources.