Role of bacterial ribosomes in barotolerance

Abstract

The effects of high hydrostatic pressures on protein synthesis by whole cells and cell free preparations of Escherichia coli, Pseudomonas fluorescens, and Pseudomonas bathycetes were determined. Actively growing cells of P. bathycetes and P. fluorescens were less sensitive than were E. coli cells. Protein synthesis by cell free preparations of E. coli and P. fluorescens showed the same extent of inhibition as their respective whole cell preparations, whereas cell free preparations of P. bathycetes showed a marked increase in pressure sensitivity over whole cells. Protein synthesis by hybrid protein synthesizing cell free preparations (the ribosomes from one organism and the S-100 supernatant fraction from another) demonstrated that response to high pressure is dependent on the source of the ribosome employed. A hybrid system containing E. coli ribosomes and P. fluorescens S-100 shows the same sensitivity to pressure as a homologous E. coli system, whereas a hybrid containing P. fluorescens ribosomes and E. coli S-100 shows the greater pressure tolerance characteristic of the P. fluorescens homologous system.

High hydrostatic pressure inhibits the biosynthesis of eukaryotic elongation factor‐2

“…Early studies in bacteria [Landau, 1966, 1967; Pope et al, 1975a,b] and eukaryotic cells [Scheck and Landau, 1982a,b] have shown that high hydrostatic pressure inhibits the protein synthesis. The activity of rat ribosomes decreased with the increase of the applied pressure, so that total inhibition was reached at 240 MPa [Lu et al, 1997].…”

Specific ion concentration as a factor in barotolerant protein synthesis in bacteria

“…The availability of both a barosensitive E. coli system and a barotolerant P. fluorescens system thus allowed for a series of experiments involving interchanges of ribosomes and supernatant factors in polyuridylate [poly(U)]-directed, polyphenylalaninesynthesizing preparations. Such experiments showed clearly that barotolerance in P. fluorescens was associated with the ribosomes rather than the soluble components of the system (13). Additional manipulation of the 50S and 30S ribosomal subunits in interchange experiments revealed that resistance to inhibition by pressure was associated with the 30S ribosomal subunit of P. fluorescens (18).…”

“…Growth conditions. Maintenance and growth conditions for each organism were essentially those which have been described in a previous publication (13).…”

“…Pressure apparatus. The apparatus and techniques used to measure protein synthesis at increased pressure have been described previously (13).…”

“…Cell-extract preparation. E. coli and P. fluorescens extracts were prepared by a modification of Modolell's method (11) which has been described in a previous report (13). P. bathycetes extracts were prepared identically with a slight modification for the experiments involving endogenous mRNA.…”