Recombinant plasmid retention and expression in bacterial biofilm cultures
Journal
Water Science and Technology
Journal Volume
31
Journal Issue
1
Pages
105-115
Date Issued
1995
Author(s)
Abstract
Any exposure of plasmid recombinant microorganisms to an open system environment, either inadvertently or intentionally, mandates research into those fundamental organism:plasmid processes that influence plasmid retention, transfer and expression. In open environmental systems a majority of the microbial activity occurs associated with an interface, within thin biological layers consisting of the cells and their insoluble extracellular polymer, layers known as biofilms. Thus any study regarding the fate of recombinant DNA sequences in an open system must consider processes that affect plasmid retention and expression in a biofilm culture. Biofilm cultures were cultivated in a parallel-plate flow cell reactor using E. coli DH5α which contained a recombinant plasmid with a plasmid stability factor, parB, (pTKW106) or without (pMJR1750). Using β-galactosidase as inducible reporter protein, plasmid retention and gene expression of pMJR1750 and pTKW 106, in suspended versus biofilm cultures, were studied under different carbon to nitrogen ratios and plasmid induction levels. Recombinant biofilm formation under these environmental conditions was also investigated. Biofilm net accumulation rate of E. coli DH5α (pTKW 106) decreases with increasing induction levels. The β-galactosidase production and ratios of β-galactosidase to total protein increase with increasing induction levels. Synthesis rates of total RNA, β-galactosidase mRNA and rRNA in biofilm cultures of E. coli DH5α (pTKW106) increase after induction by IPTG. © 1995, International Association on Water Quality. All rights reserved.
Type
journal article