Cell-substrate interactions during amoeboid locomotion ofNaegleria gruberi with special reference to alterations in temperature and electrolyte concentration of the medium

Abstract

The effect of temperature variation on the speed of amoeboid movement ofNaegleria gruberi, a common soil protozoon, across a planar glass substrate under different electrolyte conditions (deionized water and 10 mM NaCl) has been measured. Cellsubstratum interactions of this amoeba were already known to differ at 20°C in these two media. While motility was evident at 8°C in these two media, speed of locomotion increased with temperature in both media, doubling between 20°C and 30°C, only to fall off sharply above 35°C. The rate of change of cell-substratum contact at both 20°C and 30°C was studied by reflexion interference microscopy. In the light of this data possible models for amoeboid locomotion involving associated contact and focal contacts were developed particularly in relation to a possible steering role played by the anterior region ofNaegleria.