Diferencia en la viabilidad y estabilidad genética de mutantes de Escherichia coli crioconservados mediante un mismo método

Abstract

The Microorganism Collection Union (VKM) from Russia uses a simple technique for the freezing of cells on silica gel. This method has been employed in VKM collection since 1991 for the conservation of bacteria, fungi and yeasts from different species. The aim of this work was to determine whether this method can be applied to different E. coli strains that are commonly used as hosts for plasmids or as expression strains in the molecular biology labs. For this purpose, the behaviour of indicators such as: the viability and the genetic stability of genetic markers from 21 E. coli strains after liofilization on silica gel at 30, 60 and 90 d of storage at -70 OEC was studied. The stability of the strain in study was different. The authors found that the strains containing the recA or recBC mutation are more sensitive to the damages that produce this type of conservation. A study of the HB101 strain transformed with different plasmids suggests that the viability but not the genetic stability depends on the genetic information contained on the plasmids. It was concluded that the election of the conservation form depends on the strain. In the case of recombinant
strains the method is not applicable without a previous study of stability in real time. The stability varies depending on the plasmid introduced as the results of the study with the HB101 strain suggest. It's a strain of common use in the works of cloning in many laboratories.