Open AccessLacI(Ts)-Regulated Expression as an In Situ Intracellular Biomolecular Thermometer
Author(s) -
Kevin M. McCabe,
E. J. Lacherndo,
I. Albino-Flores,
Elwyn Sheehan,
Mark Hernandez
Publication year - 2011
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.01915-10
Subject(s) - intracellular , thermometer , escherichia coli , in situ , biophysics , chemistry , fluorescence , biochemistry , biology , biological system , physics , thermodynamics , gene , organic chemistry , quantum mechanics
In response to needs forin situ thermometry, a temperature-sensitive vector was adapted to report changes in the intracellular heat content ofEscherichia coli in near-real time. This model system utilized vectors expressing increasing quantities of β-galactosidase in response to stepwise temperature increases through a biologically relevant range (22 to 45°C). As judged by calibrated fluorometric and colorimetric reporters, both wholeE. coli cells and lysates expressed significant repeatable changes in β-galactosidase activity that were sensitive to temperature changes of less than 1°C (35 to 45°C). This model system suggests that changes in cellular heat content can be detected independently of the medium in which cells are maintained, a feature of particular importance where the medium is heterogeneous or nonaqueous, or otherwise has a low heat transfer capacity. We report here that the intracellular temperature can be reliably obtained in near-real time using reliable fluorescent reporting systems from cellular scales, with a 20°C range of detection and at least 0.7°C sensitivity between 35 and 45°C.