Schizosaccharomyces pombe is More Sensitive to Pressure Stress than Saccharomyces cerevisiae.

Abstract

Key words: hydrostatic pressure/Schizosaccharomyces pombe/microtubn\Qs/microfila.mQnts/^uorQscQncQmicroscopy/ immunoelectron microscopy ABSTRACT. The effects of hydrostatic pressure on ultrastructure, microtubules and micro filaments of Schizosaccharomyces pombewere investigated by fluorescence microscopy, conventional electron microscopy and immunoelectron microscopy. Cells were treated with hydrostatic pressure from 0.1 to 400 MPafor 10 min at room temperature. The nuclear membranewas disrupted at above 100 MPa. At 150 MPathe matrixes of mitochondria had an electron dense area. At 250 MPathe cytoplasmic substances changed dramatically, the cellular organelles could hardly be detected and the fragmented nuclear membrane was barely visible. The fluorescence in a-tubulin was lost in most of the cells at 100 MPa. The gold particles for anti a-tubulin were not visible in the cells at the same level. Cell cycle specific actin distribution was lost even at 50 MPa, although actin dots localized at the central region remained unchanged. Thick actin cables appeared at 100 MPa. Complete depolymerization of F-actin was observed at 150 MPa. These results suggest that S. pombecells were more sensitive than Saccharomycescerevisiae cells. The damageto microtubules and nuclear membranecaused by hydrostatic pressure was thought to be followed by breakdown of nuclear division apparatus and the inhibition of nuclear division. This damage might contribute to the frequent formation of polyploidy in S. pombe.Our previous investigations by conventional electron microscopyrelated to hydrostatic pressure effects on the budding yeast Saccharomyces cerevisiae (16) and the dimorphic yeast Candida tropicalis (14, 15) revealed that the membranesystems, especially the nuclear membrane were most susceptible to pressure stress even at 100 MPa.An electron dense matrix appeared in the organelles and cytoplasm above 200 MPa. Under fluorescence microscopycell cycle specific organization of microfilaments and microtubules was altered whenS. cerevisiae and both yeast and hyphal form cells in C. tropicalis were exposed to hydrostatic pressure stress at 100-150 MPa. Hyphal cells were found to be more sensitive to pressure treatment than yeast form cells and microtubules to be more sensitive than micro filaments (14). It was also demonstrated that hydrostatic pressure of 200 to 250 MPa greatly inactivated S. cerevisiae cells while inducing polyploidy at a high frequency of 15% (6).Immunoelectron microscopy (immuno EM) using ultrathin frozen sectioning (9) in S. cerevisiae revealed deposits of gold particles for anti a-tubulin in the nucleus at 150 MPa, although no filamentous structure of microtubules was recognized. The damageto microtubules and nuclear membranecaused by such stress was thought to be followed by a breakdown of nuclear division apparatus and the inhibition of nuclear division. Onozato confirmed that the breakdown of the mitotic spindle after application of hydrostatic pressure induced the formation of polyploidy in salmonid eggs (13).W...

Cessation of Cytokinesis inSchizosaccharomyces pombeduring Growth after Release from High Hydrostatic Pressure Treatment

“…Specifically, the patches were visible at the ends of cells that had grown to twice the normal length. Cytoplasmic actin cables are known to exist in S. pombe 12,14,15) but were not easily detected in our staining system.…”

“…14) They report the disappearance of cell-cycle specific actin structures, as detected by fluorescence microscopy after HPT at 50 MPa for 10 min. As detected by immunoelectron microscopy, microtubules were lost after HPT at 100 MPa.…”

Exploration of the Effects of High Hydrostatic Pressure on Microbial Growth, Physiology and Survival: Perspectives from Piezophysiology

“…Pressures in a range of 100 to 200 MPa kill cells of S. cerevisiae by disrupting the ultrastructure of microtubules, actin filaments or nuclear membranes. [52][53][54] Pressures greater than 200 MPa cause leakage of internal substrates and ions from the cells. 55,56) High pressure also induces cytoplasmic petite mutations 57) and tetraploid or homozygous diploid forms.…”

“…53) Even at 50 MPa, cell cycle-specific actin distribution is lost in S. pombe, whereas distribution is not affected in S. cerevisiae by high-pressure treatments of up to 100 MPa for 10 min. 53) In higher eukaryotic cells, oligomerization of F-actin is a typical pressure-sensitive process that is accompanied by a large positive volume change. 59) Compressed gases have significant inhibitory effects on yeast growth depending on the type of gas.…”

Effects of pressure stress on the fission yeast Schizosaccharomyces pombe cold-sensitive mutant nda3

“…They were treated with hydrostatic pressure of 100^200 MPa for 10 min at room temperature [2,10]. The decompressed samples were immediately ¢xed to prepare specimens for £uorescence microscopy, immunoelectron microscopy and conventional electron microscopy as described below [6].…”