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Updated: May 30, 2026
04:40
The Cultivation, Growth, and Viability of Lactic Acid Bacteria: A Quality Control Perspective
Published on: June 16, 2022
Integrative food grade expression system for lactic acid bacteria.
Grace L Douglas1, Yong Jun Goh, Todd R Klaenhammer
1Department of Food, Bioprocessing & Nutrition Sciences, North Carolina State University, Raleigh, NC, USA.
Methods in Molecular Biology (Clifton, N.J.)
|August 5, 2011
Summary
Lactobacillus acidophilus NCFM can be engineered for vaccine delivery. Researchers successfully integrated and expressed a reporter gene on the bacterial chromosome, enabling stable, inducible gene expression for potential mucosal vaccine applications.
Area of Science:
- Microbiology
- Genetic Engineering
- Vaccinology
Background:
- Lactobacillus acidophilus NCFM is a probiotic with potential as a mucosal vaccine delivery vehicle.
- Plasmid-based antigen expression is limited by instability and antibiotic selection requirements.
- Chromosomal gene expression offers enhanced stability and eliminates the need for antibiotic selection.
Purpose of the Study:
- To demonstrate the feasibility of inducible gene expression in the L. acidophilus chromosome.
- To develop a stable method for antigen expression in L. acidophilus for vaccine applications.
- To evaluate the integration and expression of a reporter gene in the L. acidophilus genome.
Main Methods:
- Utilized a previously described upp-counterselectable gene replacement system for chromosomal integration.
- Inserted the gusA3 reporter gene into an intergenic region downstream of the lacZ gene.
- Assessed transcriptional activity using GUS activity assays with 4-methyl-umbelliferyl-β-D-glucuronide (MUG).
Main Results:
- Successfully integrated and achieved inducible expression of the gusA3 gene in the L. acidophilus chromosome.
- Transcriptional activity of the integrated gusA3 was significantly higher (one to two orders of magnitude) compared to the GusA3-negative parent strain.
- Demonstrated enhanced genetic stability through chromosomal integration, bypassing the need for antibiotic selection.
Conclusions:
- Chromosomal integration of gene cassettes is a viable strategy for stable, inducible gene expression in L. acidophilus.
- This method holds significant potential for developing L. acidophilus as an effective vaccine delivery vehicle for mucosal immunization.
- The successful integration and expression of gusA3 pave the way for expressing vaccine antigens in L. acidophilus.
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