Biomaterial Database

High-efficiency transformation of Streptococcus thermophilus using electroporation. 2021

Ling-Hui Kong, and Zhi-Qiang Xiong, and Yong-Jun Xia, and Lian-Zhong Ai

Shanghai Engineering Research Center of Food Microbiology, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China.

BACKGROUND Streptococcus thermophilus, one of the most important lactic acid bacteria, is widely used in food fermentation, which is beneficial to improve food quality. However, the current genetic transformation systems are inefficient for S. thermophilus S-3, which hinders its further study. RESULTS We developed three electroporation transformation methods for S. thermophilus S-3, and optimized various parameters to enhance the transformation efficiency up to 1.3 × 106 CFU/μg DNA, which was 32-fold higher than that of unoptimized. Additionally, transcriptional analysis showed that a series of competence genes in S. thermophilus S-3 were remarkedly up-regulated after optimization, indicating that improvement of transformation efficiency was attributed to the expression level of competence genes. Furthermore, to prove their potential, expression of competence genes (comEA, cbpD and comX) were employed to increase transformation efficiency. The maximum transformation efficiency was obtained by overexpression of comEA, which was 14-fold higher than that of control. CONCLUSIONS This is the first report of competence gene expression for enhancing transformability in S. thermophilus, which exerts a positive effect on the development of desirable characteristics strains. © 2021 Society of Chemical Industry.

UI	MeSH Term	Description	Entries
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D014169	Transformation, Bacterial	The heritable modification of the properties of a competent bacterium by naked DNA from another source. The uptake of naked DNA is a naturally occuring phenomenon in some bacteria. It is often used as a GENE TRANSFER TECHNIQUE.	Bacterial Transformation
D015964	Gene Expression Regulation, Bacterial	Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.	Bacterial Gene Expression Regulation,Regulation of Gene Expression, Bacterial,Regulation, Gene Expression, Bacterial
D048249	Streptococcus thermophilus	A species of thermophilic, gram-positive bacteria found in MILK and milk products.
D018274	Electroporation	A technique in which electric pulses, in kilovolts per centimeter and of microsecond-to-millisecond duration, cause a loss of the semipermeability of CELL MEMBRANES, thus leading to ion leakage, escape of metabolites, and increased uptake by cells of drugs, molecular probes, and DNA. Depending on the dosage, the formation of openings in the cell membranes caused by the electric pulses may or may not be reversible.	Electric Field-Mediated Cell Permeabilization,Irreversible Electroporation,Reversible Electroporation,Electropermeabilisation,Electric Field Mediated Cell Permeabilization,Electroporation, Irreversible,Electroporation, Reversible