Data/hora: 05/06/2024 16:02:30

Provedor de dados: 	Electronic Journal of Biotechnology	
País: 	Chile	
Título: 	An improved system for competent cell preparation and high efficiency plasmid transformation using different Escherichia coli strains	
Autores: 	Tu,Zhiming; He,Guangyuan; Li,Kexiu X.; Chen,Mingjie J.; Chang,Junli; Chen,Ling; Yao,Qing; Liu,Dongping P.; Ye,Huan; Shi,Jiantao; Wu,Xuqian .	
Data: 	2005-04-01	
Ano: 	2005	
Palavras-chave: 	Competent cells; E. coli; Plasmid; Storage; Transformation.	
Resumo: 	This paper describes an efficient bacterial transformation system that was established for the preparation of competent cells, plasmid preparation, and for the storage in bacterial stocks in our laboratory. Using this method, a number of different plasmids have been amplified for further experiments. Competent cells for bacterial transformation were prepared by the calcium chloride method with an optimum concentration of 75 mM. Three different strains of Escherichia coli that were tested are DH5&amp;#945;, TG1 and XL1 blue, and the most efficient strain being XL1 blue. The optimal optical density (OD600) range for competent cell preparation varied for each of the strains investigated, and for XL1 blue it was 0.15-0.45; for TG1 it was 0.2-0.5; and for DH5&amp;#945; it was 0.145-0.45. The storage time of competent cells and its correlation to transformation efficiency has been studied, and the result showed that competent cells can be stored at -20&amp;ordm;C for 7 days and at -70&amp;ordm;C for 15 days. Three critical alterations to previous methods have been made, which are the changing of the normal CaCl2 solution to TB solution, the changing of the medium from LB to S.O.C., and addition of DMSO or PEG8000 during transformation of competent cells with plasmids. Changing the medium from LB to S.O.C., resulted in much faster growth of transformants, and the transformation efficiency was increased. Addition of DMSO or PEG8000 raised transformation efficiencies by 100-300 fold. Our improved bacterial transformation system can raise the transformation efficiency about 10³ times, making it becoming a highly efficient bacterial transformation system.	
Tipo: 	Journal article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582005000100014	
Editor: 	Pontificia Universidad Católica de Valparaíso	
Formato: 	text/html	
Fonte: 	Electronic Journal of Biotechnology  v.8 n.1 2005