New convenient defined media for [(35)S]methionine labelling and proteomic analyses of probiotic lactobacilli.

AIMS

To develop experimental conditions for efficient protein radiolabelling and two-dimensional (2D) polyacrylamide gel electrophoresis for investigation of stress proteomes of probiotic Lactobacillus spp.

METHODS AND RESULTS

Three chemically defined media (CDM) optimized from a commercial medium supported rapid growth of the probiotic Lactobacillus rhamnosus E97800, Lactobacillus brevis ATCC 8287 and Lactobacillus reuteri E97849, and a broad range of other lactic acid bacteria. These CDM allowed efficient protein radiolabelling, requiring as little as 200 mul of logarithmic culture and pulse-chase labelling of 20 min to detect c. 300 distinct protein spots in a mini-scale 2D-gel. Proteins including DnaK, GroEL and ClpATPases were identified from the 2D-gels by immunoblotting.

CONCLUSIONS

Radiolabelling coupled with 2D gel electrophoresis provides a sensitive means to monitor changes in protein synthesis rates in probistic lactobacilli.

SIGNIFICANCE AND IMPACT OF THE STUDY

Efficient tools for proteomic analyses of probiotic Lactobacillus were developed and applied for stress-response studies.