CONSTRUCTION AND DETECTION OF BIOLUMINESCENT STRAINS OF BACILLUS-SUBTILIS

Bioluminescence (lux) genes from Vibrio fischeri and V. harveyi were i ntroduced into Bacillus subtilis on a plasmid vector and by chromosoma l integration. The plasmid-bearing strain was highly luminescent and s table under antibiotic selection, but luminescence was lost in the abs ence of selection and following sporulation and germination. The chrom osomally marked strains emitted less light but were found to be stable without the requirement for antibiotic selection and following sporul ation and germination. Individual luminescing colonies of both B. subt ilis strains could be detected against a high background of non-biolum inescent indigenous soil microbial colonies on agar plates using a cha rge-coupled device camera. These bioluminescent Gram-positive strains could be of value in studies concerning the survival and spread of gen etically-modified micro-organisms in soil environments.