Ref ID : 7555
Andrzej Grebecki; Behaviour of Amoeba proteus Exposed to Light-shade Difference. Protistologica XVI(1):103-113, 1980
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Different body regions of moving amoebae were exposed to localized action of light or shade, produced by focusing the image of pieces of neutral filter upon the plane of cell migration, with help of the substage condenser. Amoebae manifest very clear negative photophobic responses. Light inhibition of the motory activity in the anterior advancing cell region has no influence on the motion of their body parts remaining in shade, what disproves the frontal zone contraction theory of amoeboid movement. Local application of shade to different cell regions may serve to modify the motory polarity and to model the shape of amoeba. It is concluded that an increase of illumination stimulates the contractile activity of cell cortex which forces the endoplasm to flow toward the shaded body regions where the contractile activity is lower or absent.