OPEN READING FRAME-3 OF THE BAROTOLERANT BACTERIUM STRAIN DSS12 IS COMPLEMENTARY WITH CYDD IN ESCHERICHIA-COLI - CYDD FUNCTIONS ARE REQUIRED FOR CELL STABILITY AT HIGH-PRESSURE

Escherichia coli strain JD518, a cydD-deficient mutant, displayed temp erature-sensitive and pressure-sensitive growth, The defective cydD ge ne in this strain was complemented by open reading frame 3 (ORF3), pre viously identified in DNA from a barotolerant bacterium, strain DSS12, allowing growth of the cydD mutant under high temperature and high pr essure conditions, Spectrophotometrical analysis indicated that the cy tochrome bd complex which is assembled by the CydD protein was express ed in E. coli strain JD518 carrying the ORF3 gene at the same level as occurred in the wild-type strain, Our results indicate that the cydD gene functions are required for cell stability under the condition of high pressure stress in bacteria.