title: Optimization of the green fluorescent protein (GFP) expression from a lactose-inducible promoter in Lactobacillus casei.
abstract: An expression vector for Lactobacillus casei has been constructed containing the inducible lac promoter and the gene encoding ultraviolet visible green fluorescent protein (GFP(UV)) as reporter. Different conditions to grow L. casei were assayed and fluorescence as well as total protein synthesized were quantified. The maintenance of neutral pH had the greatest incidence on GFP(UV) expression, followed by aeration and a temperature of 30 degrees C. Environmental factors favoring GFP(UV) accumulation did not exactly correlate with those enhancing fluorescence. Therefore, oxygenation, by stirring the culture, had the greatest influence on the proportion of fluorescent protein, which is in accordance with the structural requirements of this protein. The highest yield obtained was 1.3 microg of GFP per mg of total protein, from which 55% was fluorescent.
authors.affiliation: Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos, Ap Correos 73, 46100 Burjassot, Valencia, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Pérez-Arellano
authors.forename: Gaspar
authors.initials: G
authors.lastname: Pérez-Martínez
mesh_terms: D005453:Fluorescence; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D017930:Genes, Reporter / Q000235:genetics; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents / Q000378:metabolism*; D007780:Lacticaseibacillus casei / Q000235:genetics* / Q000254:growth & development; D007785:Lactose / Q000494:pharmacology*; D008164:Luminescent Proteins / Q000235:genetics*; D010100:Oxygen / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics
chemical_list: D007202:Indicators and Reagents; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D007785:Lactose; D010100:Oxygen