Virulence factor - a bacterial product or strategy that contributes to the ability of the bacterium to survive in the host and/or cause infection

Operon - a genetic unit of expression in bacteria consisting of a transcriptional start site; one or more genes, usually with related functions; and a transcriptional terminator

Regulon - genes located at dif­ferent locations that have promoter/operator or promoter/activator binding regions that all recognize the same regulatory protein(s)

Complementation -  Restores gene Expression in Mutant Bacteria. This method has been used for decades to study protein function, inactivating mutations, and protein-protein relationships

Transposon - a segment of DNA containing insertion sequences flanking one or more genes encoding a transposase and virulence genes or antibiotic resistance genes

Knockout - A knockout refers to a genetic modification in which a specific gene is deliberately inactivated or "knocked out." This technique is used to study the function of the gene by observing the phenotypic consequences of its absence

RNAi - RNA interference; the posttranscriptional silencing of specific genes by double-stranded RNA; involves two types of small RNA, micro-RNA (miRNA) and short-interfering RNA (siRNA), that bind to mRNA and induce the Dicer complex that degrades double-stranded RNA and prevents expression of proteins

CRISPR - (clustered regularly interspaced short palindromic repeats) direct repeats scattered throughout the chromosomes of many bacteria; function as a quasi-immune system against exogenous genetic elements