|
|
|
|
|
|
|
|
|||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | |||||
|
Fig. 2. The cytoplasm viscosity in E. histolytica is modified by affecting the F-actin dynamics. (A) Adherent wild-type amoeba cells were incubated in the absence or the presence of latrunculin A (Lat A) or jasplakinolide (Jas), and the cytoplasm viscosity was measured. The graphs depict the distribution of the viscosity values obtained for N phagosome pair measurements, performed in different cells and for three independent experiments. The mean value calculated (
) is indicated together with its standard deviation (s.d.). Lat-A treatment of the cells leads to a 50% decrease in cytoplasm viscosity compared with the untreated amoeba, whereas stabilizing actin filaments with Jas leads to a 40% increase. (B) F-actin distribution in drug-treated E. histolytica. Adherent wild-type amoeba incubated in the absence or the presence of Lat A or Jas were stained for F-actin after fixation, using rhodaminephalloidin. In wild-type strain, F-actin is enriched at the plasma membrane and in pseudopodia when the amoeba is polarized. By contrast, after treatment with Lat A, amoebae became round and actin filaments remained as aggregates inside the cell. In the presence of Jas, cells were flattened and exhibited a diffuse increase in the actin staining intensity throughout the cytoplasm. Scale bar, 5 µm. (C) Effect of Jas or Lat A on the amount of Triton-X-100-insoluble extractable actin. Wild-type parasites were incubated in the absence or the presence of Lat A or Jas before performing the fractionation procedure and examining the Triton-X-100-insoluble fraction. The amount of F-actin in untreated amoebae was arbitrarily set to 1. Lat-A incubation resulted in an effective fourfold decrease in the F-actin content, whereas Jas led to fourfold increase
|
