GREEN FLUORESCENT PROTEIN AS A VISUAL MARKER IN A P-NITROPHENOL DEGRADING MORAXELLA SP

The green fluorescent protein gene (gfp) was introduced into a p-nitro phenol-metabolizing strain of Moraxella sp. by chromosomal integration . The gfp-marked transformants, designated Moraxella sp. strains G21 a nd G35, exhibited green fluorescence under UV light. Molecular charact erization by PCR and Southern hybridization showed the presence of gfp in both transformants. Both transformants and the parent strain degra ded 720 mu M of p-nitrophenol with nitrite release within 4 h after in oculation in minimal medium supplemented with yeast extract, Transform ants degraded up to 1440 mu M p-nitrophenol and mineralized about 60% of 720 mu M p-nitrophenol, both in broth and in soil, to the same exte nt as the parent strain. Insertion of gfp did nor adversely affect the expression of p-nitrophenol-degrading genes in the transformants. Sur vival studies indicated that individual green fluorescent colonies of transformants call be detected up to 2 weeks after inoculation in soil . These marked strains could be of value in studies on microbial survi val in the environment. (C) 1998 Federation of European Microbiologica l Societies, Published by Elsevier Science B.V. All rights reserved.