The locus of heat resistance (LHR) confers heat resistance to E.coli.Several of the genes encoded by the LHR relate to protein folding or degradation and may thus also relate to pressure resistance.This study aimed to determine whether the LHR also confers pressure resistance,and whether LHR-mediated pressure resistance relates to pressure-induced protein aggregation.The effect of the LHR on pressure resistance was determined by cloning pRK767 and derivatives of this vector carrying the LHR,or fragments of the LHR,in E.coli MG 1655.Plasmids were also cloned in E.coli MG1655 ibpA-yfp,which expresses a fusion of the inclusion body protein IbpA and the yellow fluorescent protein,to allow visualization of protein aggregates.Protein aggregation in untreated and heat or pressure treated cells was determined by fluorescence microscopy.