Premium
Amoeboid Locomotion of Naegleria gruberi : the Effects of Cytochalasin B on Cell‐Substratum Interactions and Motile Behaviour
Author(s) -
PRESTON T. M.,
COOPER L. G.,
KING C. A.
Publication year - 1990
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1990.tb01139.x
Subject(s) - pseudopodia , microbiology and biotechnology , cytochalasin b , cytoplasm , actin , cytoplasmic streaming , biology , cytoskeleton , motility , biophysics , cell , biochemistry
The major manifestations of amoeboid locomotion in Naegleria —cytoplasmic streaming, pseudopod production, cell polarity and focal contact production—require that the actin‐based cytoskeleton be extremely dynamic. Whether these features are causally linked is unclear. In an attempt to answer this question we have used the fungal product cytochalasin B (cyt B) to dissect the motility process. This drug can perturb the organisation of actin filaments both in vivo and in vitro. Essentially cyt B acts as a molecule which can cap the barbed ends of actin filaments. Not surprisingly therefore cyt B has an effect on rates of actin polymerization and the dynamic state of actin in the cytoplasm. We have found that cyt B has a profound effect on focal contact production and breakdown. Within minutes of addition of cyt B focal contact production ceases, existing focal contacts are stabilised but cytoplasmic streaming and pseudopod production are not blocked. In conclusion it is now clear that the state of actin required for focal contact production is different from that required for pseudopod extension and cytoplasmic streaming.