Related Experiment Video
Updated: Jan 21, 2026

Using Multi-fluorinated Bile Acids and In Vivo Magnetic Resonance Imaging to Measure Bile Acid Transport
Published on: November 27, 2016
Enhanced acid-stress tolerance in Lactococcus lactis NZ9000 by overexpression of ABC transporters
Zhengming Zhu1,2, Jinhua Yang1,2, Peishan Yang1,2
1Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
Background:
Microbial cell factories are widely used in the production of acidic products such as organic acids and amino acids. However, the metabolic activity of microbial cells and their production efficiency are severely inhibited with the accumulation of intracellular acidic metabolites. Therefore, it remains a key issue to enhance the acid tolerance of microbial cells. In this study, we investigated the effects of four ATP-binding cassette (ABC) transporters on acid stress tolerance in Lactococcus lactis.
Results:
Overexpressing the rbsA, rbsB, msmK, and dppA genes exhibited 5.8-, 12.2-, 213.7-, and 5.2-fold higher survival rates than the control strain, respectively, after acid shock for 3 h at pH 4.0. Subsequently, transcriptional profile alterations in recombinant strains were analyzed during acid stress. The differentially expressed genes associated with cold-shock proteins (csp), fatty acid biosynthesis (fabH), and coenzyme A biosynthesis (coaD) were up-regulated in the four recombinant strains during acid stress. Additionally, some genes were differentially expressed in specific recombinant strains. For example, in L. lactis (RbsB), genes involved in the pyrimidine biosynthetic pathway (pyrCBDEK) and glycine or betaine transport process (busAA and busAB) were up-regulated during acid stress, and the argG genes showed up-regulations in L. lactis (MsmK). Finally, we found that overexpression of the ABC transporters RbsB and MsmK increased intracellular ATP concentrations to protect cells against acidic damage in the initial stage of acid stress. Furthermore, L. lactis (MsmK) consistently maintained elevated ATP concentrations under acid stress.
Conclusions:
This study elucidates the common and specific mechanisms underlying improved acid tolerance by manipulating ABC transporters and provides a further understanding of the role of ABC transporters in acid-stress tolerance.
More Related Videos
09:39Determination of Tolerable Fatty Acids and Cholera Toxin Concentrations Using Human Intestinal Epithelial Cells and BALB/c Mouse Macrophages
Published on: May 30, 2013
07:06Investigating Long-Distance Transport of Perfluoroalkyl Acids in Wheat via a Split-Root Exposure Technique
Published on: September 28, 2022
Related Concept Videos
ABC Transporters: Importer
In bacteria, based on the number of transmembrane helices and the chemical nature of their substrates, the ABC importers can be divided into three types:
ABC Transporters: Exporter
Responses to Salt Stress
Responses to Heat and Cold Stress
Electron Transport Chains
The ETC is comprised of...
Phloem and Sugar Transport