A non-standard trait (e.g. natural competence) is assessed qualitatively (e.g. presence/absence) and used as a natural reporter. The observed phenotype should be described in the experimental notes.

Reporter assay using the beta-galactosidase (lacZ) gene. The lacZ gene is typically fused to the promoter of interest. Differential regulation of the promoter mediated by the TF is assessed by induction of the system and evaluation of lacZ expression. Bacteria expressing lacZ appear blue when grown on a X-gal medium. The assay is often performed using a plasmid borne construction on a lacZ(def) strain.

A technique used to locate and isolate Fur sites via cloning. The genome of a target organism is digested with restriction enzymes, and ligated into high copy plasmids to create a plasmid library, which is then cloned into a cell line with a fur-repressed reporter. In cells where the introduced high copy plasmid contains a fur site, fur will be titrated away from it's binding site on the reporter (and throughout the genome), marking the colony. The cell can then be isolated, the plasmid extracted and sequenced for further study.

Primer Extension Assay is a simple method of assessing expression levels. The total RNA produced by the culture is isolated. A short synthetic oligonucleotide primer (complementary to a short sequence on the target RNA) is radiolabelled (usually with 32P) and the primer anneals to the RNA. Reverse transcriptase then extends the RNA producing cDNA. The cDNA is analyzed on a polyacrylamide gel. The amount of cDNA in a band on the gel is proportional to the amount of initial RNA, thus providing expression levels of RNA from the culture.