Shelby is an assistant editor for The Scientist. She earned her PhD from West Virginia University in immunology and microbiology and completed an AAAS Mass Media fellowship.

Mutations that disrupt the trpR gene lead to elevated production ... lactose in the environment, the lac operon is transcribed at very low levels (Figure 2). However, when lactose appears in ...

The operon is regulated by Lac repressor, the product of the lacI gene, which is transcribed from its own promoter (PI). The repressor inhibits transcription by binding to the lac operator (O).

Microbial genes, including cntA/B, the cai operon, and the gbu gene cluster, have been implicated in converting L-carnitine into TMA(O). However, the key genes and microbes remain underexplored.