화학공학소재연구정보센터
Applied Microbiology and Biotechnology, Vol.105, No.19, 7367-7378, 2021
Evoglow-Pp1 and mCherry proteins: a dual fluorescent labeling system for lactic acid bacteria
Fluorescent proteins are widely used for cell and protein tracking. Most of these proteins show a high signal and need the presence of oxygen to emit fluorescence. Among them, the fluorescent protein mCherry stands up because of its bright signal and fast maturation. Furthermore, the anaerobic cyan-green fluorescent protein Evoglow-Ppl allows fluorescent detection under anaerobic conditions. In this work, we modified the pNZ:TuR.aFP plasmid, which harbors the gene encoding Evoglow-Pp1 and the promoter of elongation factor Tu from Limosilactobacillus reuteri CECT925, to obtain a plasmid containing the mrfp gene encoding the monomeric mCherry (pNZ:TuR.mCherry). Moreover, both genes were cloned together (pNZ:TuR. aFP.mCherry) developing a chimeric protein; and with a stop codon between them (pNZ:TuR.aFP.STOP.mCherry) resulting in the expression of both Evoglow-Ppl and mCherry proteins separately under the influence of the same promoter. Lactococcus lactic, Lacticaseibacillus casei, Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Lacticaseibacillus rhamnosus, and L. reuteri strains were transformed with the previously mentioned plasmids, showing an excellent red (pNZ:TuR.mCherry), green (pNZ:TuR.aFP), and red combined with green (pNZ:TuR.aFP.mCherry and pNZ:TuR.aFP. STOP.mCherry) fluorescence signal. Both fluorescence emissions were stable in strains transformed with pNZ:TuR.aFP. STOP.mCherry, while differences in the red or green fluorescence emission were observed in some of the strains harboring pNZ:TuR.aFP.mCherry. Moreover, these plasmids allowed strains differentiation in a complex environment, such as fecal microbiota. Hence, we present the plasmid pNZ:TuR.aFP.STOP.mCherry as a useful tool for the labeling of lactobacilli strains, which would be functional under anoxic conditions, thanks to Evoglow-Ppl, while having the high brightness and good photostability of mCherry.