Patent ID: 6391549
Filing Date: 2002-05-21
Classification: C12Q

Abstract:
A method for detecting a parameter of a host cell, wherein the parameter is:a nutritional substance; a substance which regulates cell activity, growth or production of certain substances within the cell; an external toxic chemical; a pollutant, or a promoter inducible by external culture conditions, the method comprising: (a) transfecting said host cell with a plasmid comprising a B-galactosidase or alkaline phosphatase reporter gene under expression control of an inducible promoter sequence, said reporter gene being tolerant to said parameter, said promoter sequence being inducible in correlation with said parameter, said reporter gene encoding an enzymatically active product, said enzymatically active product catalyzing a reaction on p-aminophenyl-B-D-galactopyranoside as a substrate for B-galactosidase, or p-aminophenol-phosphate as a substrate for alkaline phosphatase, which gives rise to an electrical signal, said electrical signal being of sufficient intensity to be monitored by an electrochemical cell, said electrochemical cell comprising a vessel, a measurement electrode, a return electrode, and a reference electrode; (b) placing the transfected cells in an electrochemical cell; and (c) measuring the level of the electrical signal using the electrochemical cell, wherein a signal above a threshold level indicates the presence of said parameter.