E-SGRP-5 - Transcription profiling of Dictyostelium discoides mutant cell type aspidocyte induced by heavy meatals and antibiotics
Released on 6 February 2007, last updated on 2 May 2014
We describe the serendipitous discovery and first characterization of a new resistant cell type from Dictyostelium, which we propose to call the aspidocyte (aspida: Greek for shield). These cells are induced from amoebae by a range of toxins including heavy metals and antibiotics, and were first detected by their striking resistance to detergent lysis. Aspidocytes are separate, rounded or irregular shaped cells that are immotile but remain fully viable; once the toxic stress is removed, they revert to amoeboid cells within an hour. Induction takes a few hours and is completely blocked by the protein synthesis inhibitor cycloheximide. Aspidocytes lack a cell wall and their resistance to detergent lysis is active, requiring continued energy metabolism, and may be assisted by a complete cessation of endocytosis, as measured by uptake of the dye FM1-43. Microarray analysis shows that aspidocytes have a distinct pattern of gene expression with a number of genes up-regulated that are predicted to be involved in lipid metabolism. Aspidocytes were initially detected in a hypersensitive mutant, in which the AMP deaminase gene is disrupted, suggesting that the inductive pathway involves AMP levels or metabolism. Since aspidocytes can also be induced from wild-type cells and are much more resistant than amoebae to a membrane disrupting antibiotic, it is possible that they are an adaptation allowing Dictyostelium cells to survive a sudden onslaught of toxins in the wild.
transcription profiling by array, development or differentiation, growth condition
A new environmentally resistant cell type from Dictyostelium. Ioannis Serafimidis, Gareth Bloomfield, Jason Skelton, Al Ivens and Robert R. Kay.