Diamagnetic levitation changes growth and gene expression of Saccharomyces cereviasiae

Abstract

Background Magnetic flux (MF) is used in magnetic traps to levitate biological specimens by exploiting the diamagnetism of virtually all materials. However, little is known of the effects of MF during magnetic levitation (ML). This report investigates how changes in MF and gravity (GR) affect the eukaryotic organism Saccharomyces cerevisiae during ML. Methods Wild type (WT) yeast was compared to strains with genetic modifications in transcription factors Msn4, Sfp1 or Rap1 as they have been implicated in stress and gravity responses. Yeasts were levitated at various fluxes, and subjected to various gravity levels. Cell growth was determined by OD measurements in WT vs. Msn4 and Sfp1 deletion strains. Gene expression changes were determined by fluorescent content of strains bearing GFP-tagged reporters for YIL52C (Sfp1-depedent) YST-2 (Sfp1/Rap1-dependent) or SSA4 (Msn4-dependent) by flow cytometry. Results MF had no effect on growth of WT (12% reduction, p >0.05 vs. control), but it reduced growth in Msn4 and Sfp1-deletion strains (26% and 15%, p <0.05 vs. control). GR reduced growth in the WT and Msn4-deletion strains (30% and 33%, 0 g vs. 2 g, p < 0.05) but had no effect on Sfp1-deletion strain (0% change). MF increased expression of YIL52C and YST-2 strains (57% and 46%, p > 0.05 vs. control). GR reduced expression of YIL52C and SSA4 strains (41% and 65%, 0 g vs. 2 g, p < 0.05). Conclusions MF and GR had independent effects on yeast cell growth and gene expression in a strain dependent manner during ML. Supported by NASA NRA NAG8-1344, NIH P20 RR017659 grants and N.O. VA.