Evidencing microbial communication through Quorum Sensing systems in the environment: a practical approach for undergraduate students

TORRES MARIELA ANALÍA; LACOSEGLIAZ, MARIANO J.; VIOLA, C.M.; PAJOT, HIPÓLITO M.; CARLOS G. NIETO PEÑALVER

JOURNAL OF BIOLOGICAL EDUCATION

INST BIOLOGY

Año: 2021 vol. 55

0021-9266

In the environment, communication among microorganisms is a keyaspect of their lives. Through communication, single cells of a microbialpopulation can coordinate their gene expression and, in consequence,their physiology. Quorum sensing systems (QS) are one of these mechanismsthat allow this communication through the production and detectionof signal molecules whose concentration is related to the density ofthe signaling cells. In several Gram-negative bacteria, these QS signalsbelongs to the N-acyl homoserine lactone (AHL) family, which can bedetected in the laboratory by means of simple bioassays. In this report,we present for undergraduate students a detailed protocol that allows usto evidence QS activity in environmental samples. First, with a selectiveculture medium, Gram-negative bacteria are isolated from samples providedby the students. Then, isolates are screened with two biosensorstrains for the detection of AHL production. Positive results are visualizedby the induction of violacein production in the biosensors. These experimentsevidence the presence of communicating microorganisms in theanalyzed samples. This simple protocol allows the students to analyzea particular microbial activity in samples provided by them, whichenhance their learning experiences.