Phenotypic Analysis of Mutant Strains

The ultimate goal in constructing a systematic collection of mutant strains is to shed light on gene functions through sensitive, yet high throughput, phenotypic analyses of each mutant strain. In addition to the gene expression profiling information also available on this site, we also determine the growth curve properties and metabolic capabilities of each mutant.

View phenotypic analysis data
(Biolog data for 586 mutants, updated 10/13/2003; select Escherichia coli K-12 MG1655 from the genome drop-down menu)

Growth curves

A primary phenotype we assay is simply the ability of a mutant strain to grow in either minimal media or Luria Broth. Mutant strains are diluted into appropriate media contained in a 96-well microtiter plate, grown at 37 with shaking using a plate reader (SpectroMax). OD600 measurements are taken every 15 minutes over a 15 hour period, and used to construct the growth curve and maximum doubling time of each strain.

Biolog Phenotypic Microarrays (PMs)

To obtain more specific information about the nutritional requirements of each mutant, strains are assessed for their ability to grow on 480 different nutrient sources using the Phenotypic Microarrays (PM1-5) available from Biolog. Each well of these microarrays contains a single compound testing for either carbon, nitrogen, sulfur or phosphate utilization. Growth is measured using a colorometric indictor present in the plates and tabulated both qualitatively by visual inspection and quantatively by taking OD595 readings with the plate reader. An example of this assay is shown below. In this case, a himA^Am mutant was shown to be defective in alpha-hydroxy acid utilization.

Comparison of MG1655 and a himA amber mutant grown on one of the Biolog Phenotypic Microarrays. Wells where wild type grew and the mutant did not are marked with yellow circles